Yes, I know - gimmicky title. But, found this on a google search, thought it might be useful for discussion.

http://www.aardvark.co.nz/pjet/cruise.shtml

Enjoy, and discuss plenty :)

I was listening to the radio this morning before I went to school and the little talk show people had their minute before they played another song and started talkin about a guy who was making a cruise missile. Here (http://stuff.co.nz/stuff/0,2106,2518801a10,00.html) is the page with the story that I got from the radio stations site. I have put some thought into making a remote control missile before but then ealized that it would be too expensive for SWIM to do as SWIM would end up going to prison for blowing something to shit. Wouldn't having a cruise missile be great though? "DAMN JOB! AAAAAAARRRRRRRRRRRGHHHHHHH! DIE!! " I personally wouldn't have any real idea of how to go about making the guidance system now that I think about it though. What do you think would be easier to use? The one that has to be programmed or a remote type? I know that some people like the idea of "use it and forget it" but I think it may be more fun and also more accurate if it was controlled via remote system. But there would be a problem when it comes to hooking a small wireless video cam to the nose as the longest range I have ever seen on one of the wireless cams is only a few hundred meters max.

The range issue with cameras and remote control can be largely overcome by using more transmission power. You're already going to be in deep shit for building a guided missile so who cares about the FCC?

Onboard guidance would be better for long range though. During WW2 there was a scientist (can't recall the name) who created a guidance system for V2 type missiles which relied on homing pidgeons pecking buttons to steer the missile. There were 3 pidgeons and the system steered on a majority vote, to try to avoid trouble when one pidgeon had a grudge against its trainer.

GPS modules are pretty cheap - about US$50, but they might not handle speed very well, so targeting accuracy would suffer.

Forget using cheap accelerometers for inertial guidance, the signal to noise ratio is not good enough for anything other than short term backup of GPS. ADI accelerometers (http://www.analog.com/Analog_Root/sitePage/mainSectionContent/0,2132,level4%253D%25252D1%2526ContentID%253D15266 %2526level1%253D212%2526level2%253D%25252D1%2526le vel3%253D%25252D1,00.html)

I looked at the cruise missle theory several months ago and it really does not need to be even $5000, heck if you were really cheap you probably could spread anthrax with weather balloons, but that its besides the point; a canadian group has managed to drop (launch?) a glider from extream altitude (60,000+ ft) and if they can do that, how hard would it be to drop a payload from that glider (or for that matter, cut the wings and drop the glider on to the target). -If your interested in their project, the link is http://members.shaw.ca/sonde/index.htm - So in effect, its all ready been done; the technology is there, all thats required is the will.

It was just on the news here in Australia. Its a ploy to get funding for his engine he designed.

Going to the news with this saying "look how easy it is" is really bad .. what will they ban next. What a wanker.

+ supposedly he has ripped off loads of people via his website, so dont even think about sending money and expecting something in return.

Lol, I love the pidgeon idea. Imagine what the other side would have thought if they found an unexploded missile, took it to their labs to steal the technology and found it to be pidgeon-based (it'd be something like "WTF? :confused:").

Too late, I already thought up the "poor man's cruise missile" idea, although a lot lighter duty; Remote controlled aircraft + remote detonated explosive.

If you had an efficient glider design, something like a 40-1 (40 horizontal for every foot vertical) then you could get some pretty awesome range with a ballon lifting it up for miles.

Plus, with a ballon, there's no lauch signature like flames/smoke to give it away, it's VASTLY more simple to make than an engine or rocket, plus there's NO restrictions on ballon technology like there is for missles. Oh, and it's VERY cheap, compared to the alternatives.

If the glider was made of styrofoam covered with carbon fiber cloth, then it would be very light, as well as virtually invisible to radar. The body could, in fact, be explosive, using a foamed explosive to provide sufficently light density for the glider to work properly.

And, if this is intended as a "terror" weapon, like the V-series were, then who needs fancy guidance systems? Let it go upwind of a major city, timer releases it, and operator in said city uses TV guidance to fly it into the first big building he sees on his screen.

Release several at once, with staggered delays, so the operator gets to guide them in one at a time, into various parts of the city.

This removes the need for GPS, though it will replace it with the need for video transmitters/RC controls, so you may just be swapping problems, though video guidance would be much more simple to implement.

Or you could KISS this by attaching bomblets (like SWIM posted ;)) to large plastic bags, and inflating them with anhydrous ammonia (super-cheap, lighter than air). Release a couple hundred of these in mass upwind of a mega-city like LA...balloons rupture at high altitude...hundreds of bomblets fall at random over city...terror ensues. :)

Too elaborate on the balloon weapon; you could do any one of several things to really cover your tracks. First off, you could (provided your good enough) design a balloon and ballast system capable of 1. Riding in the jetstream, and 2. While making use of Gps, drop off a glider at a certain point and fly it any number of miles to a specific point or target. This opens up a whole new terror opertunity for deranged groups: Strategic bombing. The only catch, youve got to wait for the right weather conditions, and even then its rather likely something would go wrong - but if you release enough, I suspect that youll exceed at least once. The best thing is that this has been done before by the Japanese (making use of cheap hydrogen and paper balloons mind you...) Of course this is all theoretical discussion :)

if you're going to use a balloon to release a glider why not just use a balloon to release a bomb? why waste a glider as a terror weapon when balloons are a hell of alot cheaper and easier.

using a glider to carry explosives is unlikely to work too well. it simply wouldn't be able to provide enough lift to keep a large mass of explosive in the air.

unless you weighted the thing full of explosive and launched it from a very large height (balloon?). not so much a glider, but a glide bomb. some little stubby wings but sufficiently large enough to provide enough lift to control decent and allow it to travel 6-7 miles or so from the launch site. this shouldn't be an unrealistic goal if it was launched from a mile high or so. i think a delta type design would work well. lots of lift and lots of speed, but still relatively stable at low speed such as launch. infact i built a remote control glider which would be ideal if double in size. would carry a reasonable amount of explosive.

somthing like this but with smaller slightly smaller wings. if its packed solid full of explosives then the wings should give enough lift if they are a similar size to what they are now since there will be alot more weight.

http://www.airbornemagazine.com.au/images/september00covdelstar.jpg

I'm pissed off, ive had my rocket Altimeters seized buy NZ customs ive got to got talk to them and beg for them both there like $90US each and i got 2 it because of this stupid wanker .

That's a very interesting reply, maybe for pigs too !

First try to formulate correct English; then you shouldn't tell us you know the guy, because you take some risks as pigs certainly watch for this forum.
When it's about making a few explosives it doesn't matter, they don't have our IPs etc, but when it comes to 'terrorism' and stupid guys that want to make 'anarchy' it's quite different.
Re-read the rules: you must formulate all as if you had only dreamt about...

ok, lesson learned, and thanks for telling me


ill shut up now
matt

If one were to launch a styrafoam glider from a balloon, even if the glider itself was invisible to radar, wouldn't the balloon show up (providing we're talking about one capable of lifting several ounds)? As for complexity, I think it really depends on one's need, budget, and desire for reliability. At a very basic level, one could use a balloon with a timer and no glider that would drop the bomb over a random area after ten minutes, or any other desired time. Next, a simple non-radio controlled propeller system on the ballon could take the device relatively straight, and with some calculation a timer could drop it roughly where one would want it (probably not over a desired building, but in the general vicinity of a large target). Third, one could put a long-range radio propeller and camera system to drop the bomb very close to the target. Finally, the last level of a (relatively) simple balloon system would have underneath a seperately powered and guided modified glider capable of being released early to sneak or rocket towards the the target before the balloon could be detected. Of course, all of these methods could be bettered by more modification, I'm just laying out some generalities. As I said, it depends really on need, budget, and reliability. The only one of these methods that I would use to drop a bomb would be the video camera and simple powered balloon bomb dropper thingymajig. If I wanted a guided-missile system I'd modify a glider with both propellers and rocket engines. I believe estes has a lot of information on these kind of designs http://www.estesrockets.com

-Ancalagon

I read about this too. The guy lives in New Zealand and imported all the parts while the government had no clue. Later, when a high ranking govt official was asked, he said, after stuttering for a while "Oh yes, we have had our eye on him all the time". THe missile can travel 60miles and can carry a 10kg warhead. It has its own GPS system. Once the guy finishes, he is posting step-by-step instructions on how he built it. Do you think the pentagon is shitting in its pants yet???

http://abcnews.go.com/sections/world/SciTech/missile030605_call.html
That is the "abc news" with information. Now watch some kewl print off the directions once the guy posts them, build 1 part of it, brag at school, mention the E&W forum, and add some more nitroglycerin to the already huge flame of media and public stupidity...

Boris, as I've warned others, do NOT use the reply with quotes to regurgitate an ENTIRE post by someone else. If you can't make it clear what your reply is referring to without having to quote the whole thing, then you'd better keep your mouth shut because you obviously lack the needed literary skills to make reading your reply worth the worthless electrons its using up.

Ok, sorry. I didn't know.

I've alvays wondered why is it necessary for a homebuilt "cruise missile" to have an actual jet engine? Why not use prop drive? Since there's no need for keeping its stall speed low, its wings can be kept extremely small, and also the missile body will have very little cross-section surface area. A pimped out motorcycle engine (150-200hp) could push it to a very serious speed. Also, it'd have less heat signature, be more quiet, harder to trace etc.
For launch, maybe a larger "carrier" airframe (with landing gear) could be attached to the missile. After reaching the necessary altitude, the missile (sans carrier) would dive till it reaches the missile's minimal safe airspeed, then the carrier airframe would be jettisoned and the missile would continue on it's own.

Or simpler still, use a giant bungy for launch, as they do for model gliders. Prop drive with small wings might require two counter rotating props to cancel prop torque. Bungy might just provide enough launch velocity to operate a ramjet, and thats really simple!

bungee will work. you can get it to about 100m height which is enough for a little drop, say 20m, to gain some speed and fire up the ramjet. prop drive is a bad move since thats designed for re use and is quite weighty. ramjet is not.....think of the buzz bombs in ww2...

the buzzbombs of world war 2 did not use ramjets, they used pulse jets

Ramjets have no moving parts, but, they have no static thrust. This means you have to get them up to a high speed before they will burn and produce thrust. A bungee cord will not do it! A rocket motor might, if it is big enough.

The V-1 used a pulsejet, and weighed up to 13 tonnes. It was called a buzzbomb because of the noise the pulsejet made, and a doodlebug because they looked like they could barely fly, 'doodling' along quite slowly. (like 'dawdling') like the summer bugs we get down south in the summer. Some were air-launched, too, reaching as far as Manchester!

The V-2 was a much faster beast, travelling supersonically, powered by a liquid fuelled rocket, using liquid oxygen and a 75%-25% ethyl alcohol-water mixture.

The best solution to this problem is almost certainly a hybrid rocket/ramjet design. This would allow high thrust for take-off, with a long cruise due to the efficiency of the ramet at M1+ (supercruise).

Sadly, no-one has made a succesful one yet. I have a few designs, though. I shall draw one up and post it later.

There is no way you will build a rocket/ramjet design by yourself. Rockets are complex, their burning chambers need to be designed very well, they eat alot of fuel.

Ramjets may be simple to build but not simple to design, you need it to have aerodynamically correct diffuser cone and burning chamber. And even if you can build a working one you still need to accelerate it near the sonic speed

Pulsejets would be the easiest as you can design, build and fire them up by yourself.

i agree...pulsejets are very simple to build and can be started from zero, you just need a leaf blower or something to inject when starting it...another advantage of pulse jets is that you dont need a fuel pump or anything complicated like that, you can just use a pressurized propane tank, just like barbeques.

Narker,

I strongly disagree. Look on-line and you will find a lot of people who are making not just empty tubes (ramjets) but pulsejets (empty tubes with a valve at one end) and small turbine jet engines (amazingly complex tubes with turbine wheels and compressor wheels, gearing, etc. macined to very close tolerances), as well as rockets (straight tubes stuffed with a fast burning propellant compound), as any search engine will tell you.

chemofun,

all small jet engines are started this way, with a leaf blower or even a small compressor. This just saves on the weight of an internal system. As for running off propane or methane, you will find that every single small jet engine runs off gas, as the internal pressure saves the mass and, more importantly, the complexity, of a fuel system. However, the low energy in the gas means that ranges are short, and you have to carry the heavy compressed gas cylinder onboard!

Ramjets are the simplest. Rockets are second, followed closely by pulsejets, then, some way up in the difficulty stakes, are the various types of jet turbine engines.

Ramjets are also the highest efficiency at high speeds, as the following shows:

Or it would show if I could find it... Basically, the ramjet doesn't work below about .6M but is far more efficient at higher speeds. Pulsejets are terrible above about .6M. I will go find the book, get the scanner set up, etc. and post the two promises pictures then.

If you would be building just a rocket or jet engine then yes, that hybrid could work. But the topic is about a cheap guided missile. So the engine needs to be pretty big to carry its "brain" and explosives.
"a straight tube stuffed with porpellant compound" will not work there. A tube filled with for example homemade blackpowder or something else like it will not accelerate all the weight of a big ramjet, fuel for it and explosives to the speed required for ramjet to kick in. You would need a rocket engine that works on liquid fuel and has a proper burning chamber. That's pretty complicated to design and build.

But pulsejet would be pretty easy to build if you can get it to work. You just need some tubes and sheet metal.

Build wings large enough and it can fly.

For "brain" i think a compass to stay on its intended path and an altimeter from barometer so it wouldnt fall down. Then make somekind of a beacon that you are going to put on the target. When the missile gets in range, the compass part of the autopilot is turned off and it will begin to fly toward the beacon. When the signal gets strong enough the altimeter part of the autopilot turns off and the elevators on the wing are turned down so the missile will crash immidiately.

Apparently this NZ guy (Bruce Simpson) got his little project shut down by the NZ government. It seems some US officials asked them to do something about this- saying it was "extremely unhelpful". It might have had something to do with this numb-nuts publicly stating that parties in Iran had offered to pay him for his research. Clever.
Here is a link to the story http://news.bbc.co.uk/1/hi/world/asia-pacific/3302763.stm

Yeah that guy Bruce Simpson (http://www.aardvark.co.nz/pjet/) was on television here in the UK on a programme called Scrapheap Challenge (http://www.channel4.com/science/microsites/S/scrapheap/)
in which two teams are challenged to build something (in this case a jet powered buggy) in ten hours they completed the challenge successfully. No doubt the pulsejet engine could be used to power a missile effectively. Maybe I'll build a pulsejet that would annoy the neighbours ;-)

You can still use the Hamas aproach to the problem.
They use imrovised missile using potasium nitrate and sugar propellant .
they use about 10kg of propellant to send about 4-5 kg of explosive at around 6-8 km of the launch site.They use a water pipe of 180cm lenght and 120mm diameter.is very cheap to construct a weapon like this.
http://www.hamasonline.com/Qassam/qassam2.gif
http://www.hamasonline.com/indexx.php?page=Qassam/abu_awad
if you use 10 rockets in a city area you would bring panic.And is very cheap
I think that the iraqi insurgency is using improvised missiles lauched by donkey carts!!!!
Sometimes hight tech solutions are not the best way to deal with a problem .
You can read this site for the preparation of the propellant
http://members.aol.com/nonillion/sucrose.html
let me know if you think that this is a better idea

A little bit ago i found a H2O2 rocket engine for sale on EBAY, 220$ is not cheap but it might be worth checking out.

I'm not sure a pulsejet would be the best engine for a guided missile. My understanding is that in general they slowly and stealthily cruise up to their target. Reading this guys site it would seem they use massive amounts of fuel and although I know jet engines aren't all that efficient anyway it might be that they just use too much fuel for this purpose.

A simple ballistic missile would be much simpler to make and to create terror some of those would be ideal but to make a lethal strike against a specific target they would be far from ideal.

knowledgehungry, was that rocket engine burning fuel in H2O2 or just decomposing H2O2? No real point using H2O2 as your oxidiser when you can use the air is there? I don't know much about using decomposing H2O2 as a source of thrust so can't really say much about that.

Stealthy? A pulse jet? Are you mad?

Radar-wise they are big, due to the demands of a metal valve at the front, so they have a shifting face to scatter the radar back.

Audio-wise, launches could be detected from London by blind people with sound horns! They were called "buzz bombs" by some, due to the 160dB + noise they made. A friend made one, and his nieghbours called to ask WTF was happening, since he was 1/4 of a mile away, and it shook thier house! He had to wear ear plugs AND ear defenders to be able to think...

IR-wise, the pipes glow white hot, and are visible even during the day!

So no, the one thing you can say with absolute certainty is that a pulse jet will not be stealthy!

However, they are cheap and simple to build.

Another problem with the pulsjets is that the valves in the engine head wear out after around 30mins of run time, quite a few V1 'Buzz Bombs' never made it to their intended destinations.

You don't necessarily need a valve. I know this guy has made valveless pulsejets. But still they are noisy and create a lot of heat.

Valveless pulsejets have an even bigger signature! They are big and curved, and generally heavier.

I suspect that with a suitably advanced material you could make a better valve. Stainless seems good, but how about tungsten, or carbon, or titanium, or even a ceramic/glass solution?

Failing that, perhaps water or gas (LPG) cooling? I wonder if V1s were more effective on damper colder days?

EDIT: Don't forget that you get a lot of forced air cooling when the missile is doing 350+ mph, unlike static or ground-based tests.

Might it not be possible to shield the valveless pulsejet better than a pulsejet with a valve? There doesn't need to be an inlet at the front of the engine so it should be possible to make it a bit more stealthy from that viewpoint.

I don't think the advantages in cooling would justify carrying water on the missile but using the fuel might work well. He uses propane in his engines so preheating the fuel while cooling the engine might be a good idea.

Since a Ramjet and a pulsejet are similar in design (except that the ramjet uses incoming air to propel itself and operates at high speed only) you can combine the two in one body. Simply design a cover that includes the valve for a pulsejet. This cover would need a small hydraulic arm to push it into a recess on the projectile's body - at that point the engine becomes a ramjet. So, start the missile off on pulesjet - at around 250 mph mark, activate the hydraulic arm and open up the tube to act as a ramjet. I read about this a long time ago and searched before posting, but could not find the original site.I don't think it's ever been done, but it sounds good in theory, right?
The major problem here is that the ramjet would only be able to operate at subsonic speeds without a proper diffuser or spike. If you can figure out a way to add those and still have the pulsejet option, call nasa and seel the plans to them - be sure to mention me, since my rent is due any day now.

Subsonic ramjets can oparate at faster than sonic speeds, although past mach 1.5 their drag goes beyond tollerable limits due to the detatched shock cone that forms over the diffuser inlet (which is why supersonic designs use the diffuser cone or ducting). The flame holder required for the ramjet portion would also I think cause the pulsejet to be a little less efficient as they do not require flame holders and it would only obstruct the gas flow. You would have to do a very good job at streamlining the inlet once you have retracted the valves as any tubulance would badly screw with the combustion eddies and you would likely develop case hotspots.

Very true - but then again, I'm no engineer, but this should be no problem for someone that has had time to work with rockets and other forms of motivation for aerial vehicles. You may have to move away from steel in such an application - to save weight and to get the heat tolerance of the materials in line with the massive heat build ups you might envounter - or would encounter, I should say. I know the South African Air Force funded development of a Ramjet powered air to air missile - through Denel, I beleive. As usual with South African armed forces the project fell through, but the missile was fired by a solid fuelled rocket and after it reached a certain speed, intakes on the side opened up to activate the ramjet. Sounds like a plan to me. The exact design is of course not available to the public.

maarten221,

some good ideas there. If you read around the subject of the ramjet, you will find hundreds of ideas for providing static thrust, and then converting over. The only one that I know of is one which uses a ramjet engine with a solid rocket engine cast inside it. Once fired, the motor core gets it up to speed, then the core burns off enough, and the ramjet can take over, at supersonic speeds. Some missiles do this, and get 100+ mile ranges, at very high speeds (low supersonic, but that is amazing considering the range!) They are also much simpler than using a turbine engine and flying subsonic all the way.

As for making the curved (valveless) pulsejet stealthy, or aerodynamic, have you seen a picture of one?? You will never, ever get one down to the cross-section of a valved one. If you could crack the valveless straight designs (Use a CFD tool?) you can call any aerospace company and name your price!

If you guys figure out how to build this , and it works, and your fluent enough with it, you could design and possibly build a IBM - no, not the computer.:p

If by IBM you mean an intercontinental ballistic missile then the demands of such a missile are significantly different to a cruise missile. In many ways they are easier to build if you can assemble sufficient propellent. It's also not the sort of thing you can do in your garage.

Im sure that Common Scientist does not mean an Intercontantental-ballistic-missile (ICBM) because these things are obviously out of the reach for many nations let alone amatures (the propellent is mesured in the dozens of tons and the guidence is incredibly sophisticated). Tactical Ballistic Missiles are more in line for amature production, infact ~90% of the technology allready exists in one form or another.
For example, amature rocketry has existed for some time now - and it is common for them to launch rockets in the range of 200-500lbs with home produced motors to at least 25000-30000ft. Horizontal range for these type of delivery systems would be well in excess of 8 miles - prehaps up to a maximum of 15 miles. Payload could be up to 50 or so pound of whatever you wish.
The only problems I see is guidence, and the launch set-up. I suspect guidence could be controlled by adding venir elements in the path of the rocket exhaust - like the german V-2. A basic stamp could provide attitude ajustment dependant on time and the desired angle of pitch at that time.
The other problem of launch set up is not particularly hard, you only need about 20-30 feet of supported tube, the difficulty is: how do you leave / packup all that stuff in a hurry? - The police are bound to get reports of large smoke trails and loud sounds eminating from the launch site, most likely with extra help from the local airport/military base.
These problems aside, a tatical ballistic missile is probably the most fear inspiring delivery system I can think of a certainly a worthy consideration as a delivery system.

Oh- Does anyone know if norad can track such low flying projectiles?

Actuallyi did mean that, but I was joking of course! You might be able to build a computer from scratch that could control the rocket. That would be kool.

Hate to say it but most amature rockets are either 500-600 pounds OR fly to 20000-30000ft, to do both would require some VERY large motors, and I think buying ~30Kg NH4ClO4 at a time may make people suspicious. Also you would need a good guidance system seeing as amature rockets are not very predictable in the angles they fly at, you would have problems with a guidance system acting fast enough to steer the rocket as it flys (to fly 20-30Kft horizontal you would want speeds close to mach if not over, which would make steering without breaking up difficult). A slow flying plane like cruise missile is the best bet I think for amatures, no difficult or suspicious chemicals, they can carry a lot more in terms of payload and it would be easier to guide. Perhaps of you had an amature rocket launch ~45 degrees, reach max altitude over the target and then angle itself down over it (using GPS to calc position, only steering as it is falling at lower speeds an stresses, like a javalin missile).

I have designed a laser guided tandem warhead(ERA Piercing)with a 4 inch main warhead laser guided RPG, it would just cost a lot to build. you need a welding machine, aluminum tubing and sheet, copper sheet for the shaped charges, a high sensitivity infrared photocell quadrant(might be expensive) for the tip of the rocket, some electronics like voltage comparators and solenoids for the fins, so you put it in a control loop with the fins always trying to make each of the four photocells take in the same ammount of light from the laser(therefore in center), an infared laser for guidance, an aluminum launch tube, youd have to use a night vision scope or something for the site. and for the rocket motor , ammonium nitrate and magnesium powder molded like on http://www.pyrotek.org and this rocket would have a range of 1000 yards if laser guided. you can find the supplies on the internet, except the quadrant may be hard to get a hold of, i forgot the site. If someone is really serious about having this weapon and taking out a tank or armored vehicles, this is the right direction to take. I have seen patents on this. This design comes from a russian rpg that i saw on the web.

The guidance system wouldnt be that hard to fabricate, a uni student who's done Computer Engineering 1 could knock one up without to much trouble. All you need is to know some basic relational and positional algebra(vectors and matrixes, first semester maths), and knbow a bit about boolean algebra. With the excedingly acurate positoning systems avalible today(GPS, +/- 3m) it would be feasible to build a guidance system with an acuracy of easily +/- 20m, if not half that.

As to the delivery system, whats stopping you simply lofting the payload(of propoganda pamphlets) on a balistic tragectory, using an unguided rocket system, then detatching a guided payload?

Cheaper, and faster delivery to. In addition, it would be nearly impossible to ?shoot down" due to the greater velocies involved, and the smaller size.

As to the delivery system, whats stopping you simply lofting the payload(of propoganda pamphlets) on a balistic tragectory, using an unguided rocket system, then detatching a guided payload?

Cheaper, and faster delivery to. In addition, it would be nearly impossible to ?shoot down" due to the greater velocies involved, and the smaller size.
Wrong! A ballistic trajectory is the *easyist* one to shoot down, as the maths is really simple for where it will be in ten seconds time. You can also see it coming, as a ballistic missile going any real distance has to go rather high, so your radar picks it up long before your eyes or ears. Heck, your radar will probably pick up the launch, and then fire a counter battery at it!

A low flying cruise missile, however, will have a few seconds of time for intercept, and since you didn't fly it straight from launch to target, even the direction of attack is impossible to tell.

This was covered earlier in the thread.

If ballistic missiles are the easiest to shoot down, than why can't we shoot down Minuteman III's or SS-20's? In the gulf war, Patriots did piss poor in shooting down SCUDS. Also, reentering ballistic missiles are moving at hypersonic speeds that makes it tricky to get a bead on them. Ballistic missiles can be produced in large numbers that can be launched at once, tangling up air defences. Cruse missiles on the other hand are moving at subsonic speeds (<600mph) and can be shot down by sea sparrows, seawolfs, aircraft, and the phalanx.. Cruse missiles do have the upper hand in acuracy, though.

I have created the following thread on pulse jets and many different types of jets without being aware of its content may fit here. (Sorry for that.) I think the link contained in the thread may be useful for you. But resorcinol link (which is covered in the said thread) is unfortunately off-topic for this thread.

Anyway here is the Home Made Jet Engines and Resorcinol synthesis thread (http://www.roguesci.org/theforum/showthread.php?t=3876) I mentioned.

I have designed a laser guided tandem warhead(ERA Piercing)with a 4 inch main If someone is really serious about having this weapon and taking out a tank or armored vehicles, this is the right direction to take. I have seen patents on this. This design comes from a russian rpg that i saw on the web.
www.rusarm.ru/exprod.htm (http://www.rusarm.ru/exprod.htm) Its in Army under Anti-tank Guided Missile Systems. Also there are many other great/infamous weapon designs here. Happy "experimenting!"

There are Mortar shells which act , after being fired as a intelligent warhead.
The shell is suspended on a parachute and a sensor/camera in the nose detects tanks and fires the payload towards the vehicle. It hits the tank were the armour is thinnest and no reactive armour is present... on top.

Perhaps your missiles can be launched throgh a mortar to give it the right velocity to fire the jet engine.

ninja42

Ok, bit by bit.
If ballistic missiles are the easiest to shoot down, than why can't we shoot down Minuteman III's or SS-20's? In the gulf war, Patriots did piss poor in shooting down SCUDS.
Well, just because you are doing it wrong isn't my fault. SCUDs are *not* ICBMs. There was little knowledge of the launch, so they only got a few minutes warning, and the targets were entire towns, not a well-hardened target like a battleship.


Also, reentering ballistic missiles are moving at hypersonic speeds that makes it tricky to get a bead on them.
This is so dumb I'm leaving well alone! Let us just say that they are not moving at an apriecable fraction of c, and the maths is very simple.

Ballistic missiles can be produced in large numbers that can be launched at once, tangling up air defences. By Iraq? By Germany? Heck, by anyone who isn't really rich and has a major government backer? North Korea has about 20, and they have been trying for years!


Cruse missiles on the other hand are moving at subsonic speeds (<600mph) and can be shot down by sea sparrows, seawolfs, aircraft, and the phalanx.. Cruse missiles do have the upper hand in acuracy, though.
You could shoot down an ICBM with a Phalanx gun. There are just two problems. 1) Where are you going to put the Phalanx gun? It needs the target to be flying towards it to be very effective. Not towards a chicken shack thirty miles away. 2) The normal trick with an ICBM is to detonate it at 20,000ft, so as to avoid a huge radioactive duststorm that contamiates the rest of the world. Phalanx guns don't go that far. If they did, it would be easy, hence MIRV designs.

That is most of the problem. The way that you can have a cruise missile roll down the streets below tree height means that your phalanx gun can only open up when it has line of sight, and what if it is pointing the wrong way? What if there are two or more targets? You can have a swarm of cruise missiles far easier than a swarm of ICBM launches!

By Iraq? By Germany? Heck, by anyone who isn't really rich and has a major government backer? North Korea has about 20, and they have been trying for years!


just to clarify - ICBMs are hard to come by - simple balistic missiles exist in the thousands - hell probably in the hundreds of thousands if not millions. many nations own IRBM and SRBMs many nations own lots of them.

I can't find the website now but they built a guidance system for a large glider and used a weatehr balloon to take it up to something like 20,000 feet and then release. It apparently worked fine and would be a lot less expensive than the guided missile. I would assume dropping from 20,000 feet would give it some range too.

whoops found the link.
http://members.shaw.ca/sonde/software.htm
I dont think im allowed to post a link being such a new user of the forum (and I suspect I have had posts disallowed) but the mod that reads this could post it under their name or edit this one or something.
It is definitely on topic.

In the gulf war, Patriots did piss poor in shooting down SCUDS.

The patriots at that stage would have needed to be rebooted three times a day as the software became inaccurate after eight hours (reboot anyone?). This was fixed but not until after 28 US servicemen had died in their barracks.
http://www.fas.org/spp/starwars/gao/im92026.htm
http://shelley.toich.net/projects/CS201/patriot.html

Apparently Patriot misiles cannot be used in many countries due to electromagentic inteference from such mundane things as mobile phones believe it or not.
http://catless.ncl.ac.uk/Risks/20.04.html#subj2.1

They were recently thinking of banning Playstation 2s and X-Boxes from Iraq because the graphical imaging system and computing capabilities in them is more than sufficient to guide a missile using low res web cams.

Imagine how light they could be made if you remove the outer casing, disk drives, etc.

Maybe more useful as a ground to air missile/line of sight missile, but who knows?

Any ideas folks?

Video games kill... ;)

I don't think your average Iraqi bomb builder would even know how to build a guided missile since they seem to use ANFO and AP for their bombs. However, I wouldn't doubt they'd be able to guide a missile. I'm not sure if a laptop would be a better choice, but since the Xbox 360 has come out and the playstation 3 is out pretty soon, cheap used ones would be pretty easy to come by.

Just a though about the valveless pulse-jets. Have any of you though about a coaxial design. Suspend a smaller tube open on both ends inside a larger tube with one end closed. Have it firing out of the middle or if not possible to have the miuddle as the orifice doing the firing, neck the outer tube down around the middle tube and form a make shift nozzel.

I'm pretty sure that the design you propose would screw with the wave propogation/action, and would cause it to not fire properly. I may be misinterpreting what you are trying to convey though. I know that a metal cone set at just the right distance outside of the outlet will boost power and efficiency by creating a second resonancy wave that helps pressurize the incoming charge, but the end is not closed off.

Why bother with a PS2?

I've done some research into this idea myself, and I came up with the idea of using a wireless-LAN bridge, connected to a computer on the craft and a control unit on the ground.
To be fair, I was thinking of an actual remote aircraft, not a missile, but the control principles are similar.

The control hardware that you'd need on the craft would be, at simplest:

High-resolution webcam (preferably several, depending on type of aircraft)
GPS system
Digital altimeter
Servos and physical controls for steering, fuel & ignition

All these could be connected to a central computer, which in turn could be connected to a wireless-LAN bridge. Some models can transmit around 50mb/s at around a 40 mile range if I remember rightly, which would be more than enough for passing video, status and control data to and from the controller on the ground.
Alternatively, there's the possibility of connecting the onboard computer to the internet, although getting a system capable of transmitting the needed volume of data could be slightly tricky.

I can't comment on missile structure as my original idea was for a winged drone, but the idea could be adapted.
Obviously, data would need to be encrypted...and using a computer gives more scope for secure transmission than sending raw video data.

Gerbil: You may want to consider using one of these http://gumstix.com as the computer for your craft. Prices are relatively inexpensive, starting an < $100, and they bundle common expansion boards with the computer.

For example the GPSstix ($130) contains GPS, audio in/out with LCD, USB client, 4 GPIO. The audio would not necessarily be needed, unless you wanted to scare the neighbors with an "Apocalypse Now" type R/C helicopter playing "The Ride of the Valkyries".;)

A Digital altimeter would not be needed, the GPS speaks NMEA, altitude is part of that standard.

The 4 GPIO's could be used to control your servo's for guidance, possibly based on a track laid down by the GPS.

They also have WiFi expansion boards that you could use for communication back to your control unit if one did not want to set this up as a "fire and forget" type craft.

Using a modern game console would be an optical fire and forget deal, but I like the wireless lan idea!

The optical fire and forget scenario would require target acquisition and tracking programming. Not too easy for even the average tachno geek, let alone the average pissed off upstart. I would imagine you could find some basic code online somewhere though.

You could set this up with a frigging Gen.1 Gameboy and an eyetoy camera cartridge. It would take a few days to get the coding down, then some poor sod would need to build the hardware to go with it, but it would be fairly easily done.

Using a wireless LAN would be nearly impossible with the standard gear, as it has a range of about 200 meters, whilst your missile will be doing at least 200m/s. Even with the latest range boosted stuff on the new standard whose name I forget, you only get 1000m LOS. Yes, you could use a tightbeam or gain aerial, but that means you will now have to track your missile, and it is still LOS only.

I'd just go with the GPS unit and a colour gameboy camera wired together with a radio controlled plane underneath. Just try to make sure it has payload enough to be worth it.

'http://www.wirelessnetworkproducts.com/index.asp?PageAction=Custom&ID=20'

The w-lan bridge with a 10 mile range is nice, but far too bulky and expensive for use. There are some more inexpensive 3-5 mile range ones, still impractical for a missile but potentially suitable for a larger drone aircraft.
Then again, I'm not particularly literate on wireless communications and this is really only educated guesswork.

ravn, thanks a lot for that link...I might look into getting one of their systems.
Interestingly, there's a wiki on their website that lists projects that people have done with the systems. It includes UAVs :D .

As for communications, perhaps a direct internet connection would be better then messing around with w-lan? Unless, of course, there's a relatively easy way to set up a transmission system that could transmit the required data.
That said, I'm also interested in the idea of a GPS based fire and forget system.

*edit* I've just come across this how-to guide based on the gumstick systems: 'http://perso.orange.fr/pascal.brisset/chromicro/doc/chromicro.html'

'http://www.technologie-entwicklung.de/Gasturbines/Monocopter/body_monocopter.html'

An impressive bit of homemade turbojet engine and manpack! :eek:

If I were to use a control system, I should opt for an embedded system instead of a ready-made laptop computer/game console etc. They are cheap, fully customizable (read programmable) and you can save a lot of weight.

Embedded systems use microcontrollers instead of full fledged computers. There are myriads of microcontrollers having various features (serial communication ports, etc.). I even remember there is a PIC chip with built-in USB facility.

As for the communication means, I would use a radio-modem. Radio-modems can be configured to have a range of 20 kms. They are used geo-scada applications.

However the (obvious) downside of embedded systems you need to know how to program that buggers. However there is plenty of information on the net about that. Once I even grabbed an entire remote control project from the net in past. Regards.

RF wLAN bridges use high powered directional gear, which is useless without LoS! With LoS, you can get 50 miles with home-made-in-a-day gear, and the record is something like 158 miles.

To show you the problems with it, get a laser pointer, and track your friend running around at 100 yards. Now tell me you could do that at 50 miles on an airplane!

Anyway, even 20 or 50 miles is useless without line of sight. To get LoS, we need higher ground, and for the tightbeam we need auto-tracking.

You get a second drone up, nearby. You can see that. It can see the target drone, at 20 miles. It has a microprocessor (PIC) that tracks the two targets with either a dish, or, preferably, a steered array. One issue solved, but at the price of reliability, cost and failure modes.

Like already mentioned, instead of using a video console or laptop it's much more practical to use microcontrollers.

Just use one with four PWM channels to control the servos, one for GPS data, one for sensor inputs like three PIRs with metallic cones to follow a heat source and the master controller to decide which direction to fly and when to do KABOOOM ;)
Put it into a cheap inpeller driven RC model and let it fly in circles.

Then all you need is a RC5 remote control with a laserdiode/-pointer instead of the IR-diode and a IR-sensor to mark your target.

After marking the target the cruiser will adopt the IR signature of the target itself and follow it.

I dont thing the laser pointer idea is what he had in mind, that would be better used for assassination style things, a plane fly in circles until your target came into view would be just asking to be caught IMHO

Personaly I like the idea of an programable system, more control options and what have you, Maybe with a small memmory to store topo information, I do not feel that this is beyond range of a none mil program

You can get the topo info for free, not that you really need it.

I think this is doable by any medium sized company, or a rich & technical guy. I saw a video earlier of a guy flying a jet powered radio controlled plane, awesome stuff. http://www.dump.com/vpzve/ in fact. The KE in that thing would kill a car!

Control the thing via GPS and away you go. Terminal guidance would be via some kind of beacon, or, perhaps, pattern recognition.

{Self-edit: I'm not going to say that in public}

Jack I was thinking along the lines of a fire anywhere type thing, you never know what/where you next target may be,

Its nice to know you can get the topo maps cheap/free

Early version of Tomahawk cruise missile used topo info AFAIR inside the memory of guidance control unit. Is it still the case I don't know. Sure as hell is that today they added GPS to it.

As for tagging target idea with laser pointer, cheap and effective system is the one Russians developed for their artillery units...laser guided rocket propelled granade :D...beautifull isn't it? It is hard to hit flying granade in just a few seconds till it hit the target (possible yes but I wouldn't put my life in the hand of such system...I would most likely seek to find the marksmen and hit it with a sniper before I'm locked as target).

Too late, I already thought up the "poor man's cruise missile" idea, although a lot lighter duty; Remote controlled aircraft + remote detonated explosive.

You got pretty much the same idea as me. A powered glider design would be good for this. The long wings would provide optimal lift with minimal power. Depending on the load to be carried, it may be necessary to strengthen the wings a little to take the loading, but non explosive weight tests could be preformed to see if this was necessary or not.

The idea of dropping from such a high altitude with a large balloon is interesting. While it may seem like a waste to use both a rc plane/glider and the balloon consider that the plane/glider will allow you to be far from the site of detonation and much easier to control than the balloon which is somewhat at the mercy of the wind. However dropping the plane/glider from such high altitude would allow it to glide much further in (or out depending on perspective) to the target, and also saving an immense amount of energy expended by the winged aircraft to get to the high altitudes needed to glide to the target.

One thing you could do quiet easily, provided that your aircraft had some sort of pusher prop arrangement and a normal nose with nothing to get in the way would be to use a impact triggered detonator to make it go kaboom. This would save a little weight and increase your range slightly. With 10-20 of these you could reek havoc on a city miles away from you.:D

Why destroy your plane at all?

Why not make a bomber out of it altogether? The whole point of a cruise missile is speed, accuracy and distance from target. If your going to use an RC plane you lose speed. To get accuracy you would need to be close to the target and if you are far away from your target you lose accuracy.

If you were to get a big RC plane and overpower it to enable it to carry extra weight you could fit your own custom made bombs underneath the fuselage. Just install a receiver with one extra channel and fit an extra servo in the plane to activate a latch underneath the fuselage which would release the bomb when desired. You would also need to have a camera to sight the bomb.

By reusing the plane you wouldnt need to worry about the cost so you could spend more money on it to get better range, power and altitude.

If you could get more range out of an electric powered plane it would be even better since you get near silent approaches!!:D

That wouldnt be a guided missle, that would be a RC bomber

I know that. Im just making the point that a disposable RC glider with an explosive in the nose isnt really a guided missile. You might as well use an RC bomber since you would still need to be fairly close to your target to be able to control it and at least it can be used again at minimal cost.

What you need is something where you can choose your target, launch a safe distance from your target - at least a mile - and walk away from it. Thats where GPS comes in handy.

If great accuracy wasnt a concern, you could always go for the V1 type guidance system. Have a compass on board to steer it in the right heading and a gyroscope to keep it flying level. Then have a small propeller in the nose turning a threaded bar with a nut on the bar which moves back along the bar as the missile flies. When the nut reaches the end of the bar it joins two contacts to complete a circuit and send the missile into a vertical dive. The distance would be preset by having the nut starting at different places along the bar. You would have to do a few tests beforehand to know how far down the bar the nut will travel for a set distance.

A bit cheaper and simpler than GPS but less accurate. It did work to hit London from France though! If you could get the right propulsion it would be fine for terrorising but not for anything super accurate.

A $100 computer, With $?? gps unit, less then 300 for the basic guidence system, 2000 times more accurate as a threaded bar.

The V1 type weapon was a terror weapon and a waste of resorces that could have gone to power there air force\bomber's but thats another story

V1 wasn't waste of resources IMHO. It costed about 500$ at that time. It was too simple, had sky-jump lauch system that was weak point since it was stationary and was too slow and low flying so figher planes could intercept it.

V2 was waste of resources at price of the 250000$ per unit but was superb weapon of that time, had mobile launch platform, balistic trajectory, supersonic velocity and even had radio controled guidance of some kind (not very accurate though it could hit anywhere in the 8 km radius from the target launched at from 400km distance).

You could also use that baloon you proposed as repeter (I hope that is the right word). You focus the beam for the conection with baloon to narrow region and track its movement so it is harder to jam it. On baloon you have a repeter/transponder that emits your signal downward to your launched probe/sonde/plane/missile. Just make it powerfull enough and that with combined with position of the baloon and your "missile" (which should have upward mounted antenna) could make a poor mans guided projectile that is hard to jam.

Vod, that's vaguely what I had in mind myself. However, you're not going to get enough power out of an electrical system, unless you're talking about carrying very small charges over a short distance.

Also, if you wanted to do some serious damage, other equipment such as GPS and several mounted cameras would be needed to effectively control it over a distance. Otherwise you're going to be stuck with the equivalent of shooting cans with an air pistol :( .

*edit* Missed Page 4 for some reason :rolleyes: .

A V1 system would be next to useless for modern conflict. However, it might be possible to use the original fuselage and pulse jet design (someone with the right tools could probably build the engine alone in an afternoon), and add modern guidance equipment to it.

V1 wasn't waste of resources IMHO. It costed about 500$ at that time. It was too simple, had sky-jump lauch system that was weak point since it was stationary and was too slow and low flying so figher planes could intercept it.


That makes it a waste of resources


V2 was waste of resources

yepper, but it was way better then the V1

repeter
Repeater, When you have problems with spelling of words type them into google, it will usally show you the correct spelling

( I know this because I use it all the time )

A $100 computer, With $?? gps unit, less then 300 for the basic guidence system, 2000 times more accurate as a threaded bar.

A compass and gyroscope system would be much easier for the average person to put together rather than fiddling with electronics. A GPS is fine for telling an intelligent human being where to go but you would have to have a little more than basic knowledge of electronics to be able to convert those signals to physical movement. So if it was only needed for terrorism a compass/gyroscope/threaded bar system would be easier to put together.

It was too simple, had sky-jump lauch system that was weak point since it was stationary and was too slow and low flying so figher planes could intercept it.

Sure it was too slow and could be intercepted by fighters but that turned out to be a positive trait. Regular V1 launches had the allies constantly trying to track them on radar, they had spotters on the ground to constantly give updates on sightings and then they had to use their newest and best fighters to be able to keep up with it. This meant a lot of their new fighters were off chasing V1s when those resources could have been used elsewhere.

Even if they didnt reach their target they still succeeded in using up allied resources at minimal cost.


However, you're not going to get enough power out of an electrical system, unless you're talking about carrying very small charges over a short distance.

Thats why IC engines would be much better for the job and you could give them better range but then you have a noise problem. You just wouldnt be able to stealthily get over a crowd or other target with an IC engine unless you had an extremely good muffler.

I think that in the end, it depends on what you hope to achieve. For example, look at the Israel/Palestine conflict. Hamas are using what practically amounts to science fair bottle rockets to bomb civilians- the problem is that they aren't very powerful and highly inaccurate.

If they copied V1 blueprints, the situation might just change. It may be low-tech, but it's far better than what they're using at the moment- greater range, greater power, greater accuracy. Plus, the Israelis aren't expecting to see Nazi memorabilia flying through the sky towards them.
The sound of the pulse jet would also terrify the targeted population, adding to the terror effect.

Of course, within a short space of time, Israeli defences would be able to take out almost all of the incoming V1s. But the initial effect would still be devastating.

Gerbil, that would definitely terrorise the isrealis. its not as if they arent scared stiff already. The children there are taught how to act in case of a terrorist attack from a very young age!

I heard from a friend who had been there that a balloon burst in an isreali shopping centre around christmas time and all the isrealis hit the ground, children and all!

Can you imagine what even two or three V1s would do to them?

Hi. I had another idea for propulsion.

As ramjet is together with pulsejet probably the simplest ideas for propulsion so far, and the pulse jet having many disadvantages for the ramjet, I was thinking a simpler launch system for the ramjet to get it up to sufficent speed.

What if we use that cheap simple weather-ballon to lift up the missile to a very high altitude, and then drop it straight down to achieve enough speed for the ramjet to work efficently?

As the atmosphere get very thin at very high altitudes, the terminal velocity would increase dramatically.

Once you got that ramjet up to efficently working speed, the ramjet is a much more desirable propulsion than the pulsejet. And its also very simple.

++++++++++++

Ramjets require Mach 3+ speeds to work. And the higher up you go, the faster you must go to achieve supersonic speed in the thinner atmosphere, thus freefalling to that velocity is impossible. NBK

Even at a low of say $10,000 per I dont think I would use that method, Would rather use railroad tracks and some type of booster rocket to get to take off speed ( ? 600 mph ? ) where the ramjet can be activated, And i'm sure with a little searching you can find a long ( 2 + miles ? ) straight set of tracks that have not been used for years

And i'm sure with a little searching you can find a long ( 2 + miles ? ) straight set of tracks that have not been used for years

Probably...but I think that you might get some undesirable attention from a nice police officer if you started launching missiles from it ;) .

Ramjet need AFAIK 1,5 Mach to start and can work until Mach 6 is achieved, so I guess Mach 3 NBK stated is optimum velocity for that kind of drive method. But even this number need to be checked again for your scenario...there was on Wiki I think some kind of table that explained influence of atmospheric pressure on various propulsion methods (ramjet, scramjet etc.). The higher you are up you need higher velocity to make the "breeding" kind of engine to work.

Anyway drag of air, no matter how well you designed your projectile, will make achieving that velocity impossible or unpractical. But there is a project of space launching system that is tested and it use baloon as launchpad. So I guess you are looking in the wrong direction....on to the stars son! ;)

Engine chambers/intakes/nozzles every-fu*king-thing must be changed from ussual sea-level design to optimise that propulsion for new pressure and flow parameters so this is not a job for one man but entire team of army experts.

Probably...but I think that you might get some undesirable attention from a nice police officer if you started launching missiles from it ;) .

How many are you planing on launching ?? 1 ? 13 , Having done more reading on the subject think you could if designed better use around 500 feet of straight track you get airborn, But now the missle looks more like a glider with larger wings to provide lift

Nasa has some interesting reading on the subject of ramjets, after playing with there "enginesim 1.7a" I think that a ramjet is not effecient enought, How many people have access to multi-tons of fuel for a long range missle using ramjet, And ramjet is not worth while short range

The ramjet is the most efficient engine design in it's speed range of 2 to 5 Mach, if only because it is the *only* efficient design in those speed ranges. The power-to-weight is unbeatable, as is the thrust per unit fuel.

Going back towards the topic, you are daft if you try to make a radio controlled bomber. You would need either a very neat system to aim the bombs correctly, or you would need a second set of radio controls to steer it! And since you are probably only after a single target, you would be carrying only one bomb, or perhaps two. After two bombs fall, they are going to have started looking for your plane and checking radio traffic. Then they follow the RC bomber back to your base.

Far better to use the simple idea to the max, and use a fairly large plane to carry a far higher ratio of explosive to the terminal target, and not worry about what to do next.

The V1 was a brilliant idea. With a few hundred thousand more of those, the Germans could have run out of planes all the faster. The warhead in a V1 was relatively small, and expensive, and all the non-explosive stuff was dead weight. In a war, that is wasteful, as you have a nice plane and cheap labour you can re-use x times, dropping n bombs (which are cheap) each time. With a V1 you get 1 use max. and 1 explosion.

The Allied forces couldn't follow the Axis planes back, as the Axis had it's own planes, and it was symetric warfare. A cruise missile is used for asymetric warfare - you either can't afford a pilot (or a pilot to be lost) or you don't want it to be traceable.

Yes Jack is right ramjet is very efficient, but whole story started with free fall "jump-start" of ramjet engine...which I think won't work. But ramjet is used even today on some AA rockets, and I think Russians had a design (tested on pilot scale) for ICBM which had one ramjet stage - project was named GNOM :D (now that is appropriate name). It was supposed to have 29t weight rocket which is great even by todays measures. Today Russia is developing booster rocket system named Baykal that should use ramjet engine to return back the rocket booster to cosmodrome and land it on the paveway on its own landing gear in autopilot mode...now that is neat and I guess they finaly become bored to chase remains out in tundra. USA also worked on similar ICBM concept before USSR but quit that before any projectile were made AFAIK. So to put the story short...yes it is very good propulsion method but also a complex engeneering problem for those who should design the engine and projectile.

As for the V1 I think we are on the same side, but you seem to exagerate the effort Germans put into their production. Most of the V1 bomb was wood (well it did cost 500$), except naturaly the engine which was so thick that fighters had problems to damage it by shooting, since machineguns bullets just bounced off, so they had to use cannons (at closer range)...and sometimes if you aim wrong and that projectile hits through the wooden bomb body...BOOM!..and here goes down the bomb and brave and unlucky (poorsighted) pilot with his plane. Much later they discovered that bomb was instable in flight and that their gyroscope could be offset by rapidly pushing V1 with planes wing off-route. Small warhead is tradeoff for the simplicity of the design and low power engine they used.

I don't think anyone thought about this thread along the armed UAV lines Jack though that is tempting idea. Cheap (one use only I guess) Guided (now this is open subject) Missile (well I guess this means explosive warhead although someone mentioned kinetic energy and I wasn't sure what he mean as the projectiles that I have in my mind linked to those words use exotic rocket propulsion systems with high velocity).

Much later they discovered that bomb was instable in flight and that their gyroscope could be offset by rapidly pushing V1 with planes wing off-route.

Which has got to be one of the coolest, ballsy-est maneuvers in all of WWII aerial warfare!

Where there's a will, there's a way...

If the Nazi's had known about it, it would have been easy to counter, by making the V1 instantly explode if knocked out of its normal vertical flight profile, taking any brave pilots out with it. :)

I'd have made it do that anyway! I believe the system only armed the warhead after it started to decelerate, which meant that a lot of the bombs failed to go off when they ploughed into soft mud in the estuaries. A better way would have been a simple timer set to, say, 5 minutes. This would ensure it didn't take out the launch crew. The Germans always love to over-engineer. The Tiger tank was worth between 4 and 10 Shermans. The US made 10 for every one Tiger, and nearly every part could be canabilised for spares for another. The Tigers couldn't even be swapped between the same design revisions! But that is by the by.

A cheap COTS GPS mapping system is well below £150 now, I suspect they are cheaper in the US. I've also seen GPS modules that are perfectly suitable for under $50 on the web, designed to be integrated into a system.

Digital compasses cost about $10 each, last I looked, and two or three of those at right angles would give a great way to measure location from the magnetic deflections as you pass by.

Last I heard, the UK's fighter planes had big brass and berylium gyroscopes in them, as well as compass, radar locators, visual cues, etc. and the pilots basically mash up the data set to ensure they are where the instruments say they are. More instruments means greater likelihood of being correct, as GPS often drops out for a short time (few seconds), which at 600mph is far too long, or SA might be turned on in your area, or you might lose lock, or whatever. Also, depending on the target value, GPS jamming might be in use.

Cheap silicon gyroscopes are also available (ok, comparatively cheap) which are used in R/C helicopters to keep them flying straight without constant adjustment of the tail rotor torque. 3 of those tied together (or a bought unit) would provide a poor man's inertial navigation system!

The thing about inertial units is they drift. The rate of drift is always different, and they are always drift in different directions and so you cannot trust them over long time periods. GPS cannot be trusted over short periods. Glue the two together with a basic compass, in software, and you can be pretty sure of where you are for anything you need to do. Lose GPS for the terminal phase? Use the inertial for the next 25 seconds, and it's not an issue. Gyros drift so you are 14 miles out at max range? Who cares! You can reset from a few GPS data points.

Going back for a moment to the ramjet issue, they aren't used for spaceflight becuase the time that a rocket spends in the lower atmosphere whilst going fast enough to be using a ramjet is under 60 seconds. It simply isn't worth the extra mass of an angine that is just drag for so much of the flight profile. For a high-speed missile, however, they are ideal. Use a hybrid rocket/ramjet design, and boost the missile to Mach 1.3+ before the rocket burns out, the empty tube of which is a ramjet and core. This carries on burning and boosts or maintains the speed for a far longer time than any rocket, as it takes its oxidiser from the air instead.

Sure it is difficult, but so is the whole project! I'd start with a design that used a solid rocket motor that was carefully packed around the central flame holder and had a solid fuel in the design. On ignition the bottom half, under the flame holder, burns as a rocket would. On burn-out, the final action is a small charge that shatters the rocket nozzle, and ignites the next stage, the fuel flame holder. You might also want a nose cone to pop off so the design starts off aerodynamic for a rocket, before becoming aerodynamic for a ramjet.

The whole idea of a ramjet missile sounds just like the article in this months Popular Mechanics, about the X-51 hypersonic cruise missile (AKA Prompt Global Strike) which is designed to hit Mach 5 — roughly 3600 mph, and destroy a target anywhere within 600 miles of its launch in under 10 minutes.

http://www.popularmechanics.com/technology/military_law/4203874.html

Jack my congratulations on your ideas and determination. You are again correct about ramjet and spaceflight, but GNOM was ICBM project (if your sentence has any relation with mine post). And if you look last Russian test they used lower balistic trajectory then usual and warheads had separate guidance system and autonomous propulsion in final phase...so maybe they dig up that project from the archive back again just a little upside down. I'm also prone to over-engineering things :) so I love German stuff although V1 wasn't over-engineered but oposite over-simplified IMHO. Jack if you need any help with your project I would like to help you...I had an idea about ramjet once but alas it isn't my field of work and I find it above my powers but I guess I could be usefull member of a team. I totally aprove your point in system redundancy needed for safe/reliable flight. I follow space programs very much and I'm unhappy about Soyuz last revisions since they cut some system out (as redundant and therefore not needed) and over-integrated things too much for my taste since I wouldn't like to sit upon hundreds of tonnes of rocket fuel and got "burned" because fu*king monitor on central console burn-out.

NBK mentioning of the Prompt Global Strike dig up an info from the back off my brain about old USSR GR-1 (and 2) project. That was practically space launch of warheads in LEO so that they could hit any target on Earth, but I think they didn't implement that anywhere except in space exploration (good for us lovers of space) - lots of good things has come up from projects that initialy started as military top secret weapons project. That is how I know a much about different rocket systems although I'm quite peacefull guy. Awesome article NBK thanks.