I did a little test a while ago with two polumnas on a metal toy truck. The one on the left was filled with HMTD and one on the right was filled with AP.

Here is the <a href="http://members.shaw.ca/exim/clips/polumnas.avi" target="_blank">clip.</a>

The polumnas were both the same size (standard 1" inch polumna), but they were taped differently. The HMTD one made the huge dent in the metal truck and sent it flying, but the AP one didn't launch it as far as the HMTD one.

But, They were made differently (HMTD had hockey tape, and the AP one had duct tape), so that could of affected the performance.

here is the dent to the metal, on the side of the HMTD polumna.
The AP one didn't do much.
<img src="http://members.shaw.ca/raydawg/pics/truck1.jpg" alt="" />
<img src="http://members.shaw.ca/raydawg/pics/truck2.jpg" alt="" />

Both those pictures look almost the same. Although I've found AP to always have a little more power.

If you watch that clip closly you'll notice that after the fist explosion that the truck is tipped on it's side whitch is what I think blew it across the screen. I'd try and explane this further but it's late and I'm going to bed.

Well they are actually the same side of the truck, aren't they?

I agree that the truck was knocked onto it's side after the first blast, so it occurred to me also that there was a degree of added confinement at play. Having said that, the first explosion produced a lot more sparks, and a lot less smoke, whilst the second was clearly more powerful. I think that's more to do with the nature of the explosives than the truck being on it's side.

it most definately is the same side as no amount of twisting and turnng could get the front of the truck ending on the right for different sides. hope that makes sense. also... there are the smae features on both pics......think hes posted the wrong pic accidently.

the second one did seem more powerful but the gas had much fewer excape routes. it can't excape thrugh the ground so had to puch the truck out the way. the first blast had a large area to expand into and nothing to push against. the second blast, the pressure under the truck would be more and remain for longer due to the ground limiting expansion. does that make sense?

...or call it just simply tamping. The second charge was tamped by the ground which reflected the explosion's power towards the truck.

<small>[ June 08, 2002, 05:29 AM: Message edited by: PYREX ]</small>

If you move through the clip frame by frame you will also notice that just before the second explosion the truck starts tipping to the right of the screen, which does two things:

1) The tipping would give it a bit of motion to the right, aiding in the explosion moving it so far (but very little effect)
2) On the first explosion, the polumna pushes the truck parallel to the ground because the truck is flat with the polumna on the side, giving it force straight across the ground. In the second, because the truck is on about a 45* angle, the explosion forces it into the air on a 45 degree angle, making it fly a lot further, because its going into the air, not scraping along the ground, i hope that made sense.

And yes if you examine the two photos closely, they are both the same side from different angles.

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">here is the dent to the metal, on the side of the HMTD polumna.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">I think Rat Bastard meant to post the same side of the truck for both pictures.He just wanted to show different angles of the truck and the damage done.