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Guest

Jeeze Slide I was looking for a little more definitive and concise answer to what has got to be an easier explanation without getting into forcing cones, hull thickness etc. etc. Something like as volume increases pressure decreases.

Going back a number of year (actually a whole lot of numbers of years) I studied all of the nuances of rotary wing (helicopter) aerodynamics form the application of Bruneili's theory, gyroscopic progression, leading and lagging blade angles and flipping and flapping and a whole bunch of other "stuff" and came to the learned conclusion that the reasons helicopters flew is because of magic. So can we limit the discussion to really elementary "stuff".

Oh and SPR have you heard of the term "hypothetical".

Member Joined: 02 Oct 2007 Posts: 1975

Back in 1982, I was assigned the job of installing a 5 meter satellite dish on top of a hotel in downtown St. Louis, MO. The building was too tall for a crane. We hired a helicopter to lift the assembled dish up into position to be bolted to the support frame instead. Dispite my objections, the pilot insisted we strap the dish to his winch in a horizontal position to "avoid turbulance." Think of the dish as a drag chute deployed directly under the main rotor. The result was that particular helicopter did not fly very well once it hit the end of the cable. It kinda reminded me of a very big U-control model airplane. Boy was that pilot a surprized cowboy. I wonder if he had to go change his shorts after we unhooked him. Cool

Guest

*Last edited by 16gaugeguy on Fri May 22, 2009 12:34 pm; edited 1 time in total*

"What we have here is a failure to communicate."

Well TB, actually...no. I guess you have not grasped the gist of my little story. Stay with me now. I promise to type slower for you.

The satellite dish I'm referring to was 5 meters by 8 meters and was a quasi-spherical unit shaped kinda like a big oblong shaped salad bowl...dish side up on it's back. The support lines were attached at each corner and the chopper was tethered to the whole mess directly above it. The prop wash was blowing directly down into this big, oversized salad bowl. Got the picture. Pressure. Air pressure. Downward air pressure. It's still about pressure. The poor helicolopter just could not cope with the resistance to its own prop wash. We reslung the dish from the two top corners and she went right up like old Jack in the bean stalk...after the pilot went and changed his skivvies. Wink

However, I find the image of some poor chopper pilot trying to cope with what amounts to an out of control giant bunged up u-control model wired to his ass amusing as all hell. The things we humans do to each other just makes me scratch my head sometimes.

Well, anyway, I think we've managed to highjack another otherwise useful thread. I'm gone. See you all in the next one. Very Happy

Guest

Slide,

You hit the nail on the head, and explained it better than I did.

Every shotshell load has its own set of dynamics. You can't take any one variable and make blanket statements. Whether it be a certain hull or primer or wad or powder you can not predict what they are going to do all the time and be right.

The only thing that is constant with shotshell ballistics is that there are no constants.

Now pissing around with these little light loads seems to be easy and in general it is. Start using some heavier payloads and things start flipping around. You dont always get what you want, and blanket statements and ideas will get you a very large bill for labor without many loads to show for it.

A real interesting topic here - as usual - all over the place.

I would like to point out my post was about an easier way to measure case volume than using water, as 16GG was saying. In no way was the post asserting that similar volumes yield similar results - something that DC37 failed to note.

So, I suppose now I will be the target of one of the flame wars that perpetually clutter up this site.

Guest

Nah Topcat,

You aren't a condesending know-it all, that constantly insinuates that others aren't very smart or have common sense. That's the kind of thing that starts the flame throwing.

Guest

deleted

Member Joined: 19 Jan 2008 Posts: 680 Location: MAINE

Could this be another pissing match brewing ? And what's this about ....... Helicopters . And who's involved ..... Let's see , the expert with a background and ............ Will it ever stop ?

Member Joined: 07 Jan 2008 Posts: 348 Location: Missouri

Anybody have testing results back and willing to share?

Joined: 12 Jul 2004 Posts: 118 Location: N.Y.

Guest

mtjim

I have 2 loads out for testing now and 4 more to go once I find out where I am with the first 2.

I will make the data sheets available to everyone.

Joined: 23 Jan 2008 Posts: 224

mtjim,

I have 3 loads for the DR16 at testing right now as well. I plan on posting my results here and in the LPG whenever I get them back.