Page 7 of 8

Re: GGDT/HGDT Request Thread

Posted: Tue Sep 22, 2015 5:10 am
by topelitemarine
what value does GGDT use? Cm or inches?

Re: GGDT/HGDT Request Thread

Posted: Tue Sep 22, 2015 6:17 am
by jackssmirkingrevenge
It can use both, go on file -> configuration to change the units

Re: GGDT/HGDT Request Thread

Posted: Tue Sep 22, 2015 7:39 pm
by topelitemarine
jackssmirkingrevenge wrote:It can use both, go on file -> configuration to change the units
Got it thanks

Re: GGDT/HGDT Request Thread

Posted: Sun Apr 22, 2018 9:18 pm
by Cthulhu
Does this look right for a modified 1 inch sprinkler valve?
I'm getting very odd results using the optimization tool (such as a 1 inch chamber to 100 inch barrel).

Re: GGDT/HGDT Request Thread

Posted: Mon Apr 23, 2018 10:07 pm
by Ragnarok
I'm going to hazard a guess that the diaphragm in a sprinkler valve doesn't weigh nearly a pound and a half...

Personally, I don't think GGDT's optimiser is fantastically useful, except in fixed overall length mode (maybe). It's perhaps an interesting lesson in efficiency, but trying to eke every last joule of muzzle energy out of the compressed air leads to launchers that are highly size inefficient.

It's like vehicles from the Shell Eco-marathon, where they try to do thousands of miles on a gallon of fuel. Technically interesting, but wildly impractical for every day use.

Re: GGDT/HGDT Request Thread

Posted: Tue Apr 24, 2018 12:27 pm
by matti
Cthulhu wrote:Does this look right for a modified 1 inch sprinkler valve?
I'm getting very odd results using the optimization tool (such as a 1 inch chamber to 100 inch barrel).
That should be 22g (grams) not 22oz (= 620 grams) :wink:

Re: GGDT/HGDT Request Thread

Posted: Tue Apr 24, 2018 10:11 pm
by Cthulhu
Thanks guys, I feel like an idiot for not noticing such a small unit error :oops:

Re: GGDT/HGDT Request Thread

Posted: Wed May 09, 2018 8:52 am
by Sear
Hi guys,

I finally tried GGDT and it is really useful tool. If nothing else I was able to calculate the drag coefficient of my shots based on that :)

Is there a way to calculate the velocity at a distance? Like I would like to calculate a velocity drop after 50 meters, can I do that inside the tool? Or is there any online calculator capable of doing that universally? So far I have found only a simple ones or those suitable for rifles and bullets only.

Thanks

Re: GGDT/HGDT Request Thread

Posted: Wed Jun 13, 2018 4:26 am
by jackssmirkingrevenge
Is there a way to calculate the velocity at a distance? Like I would like to calculate a velocity drop after 50 meters, can I do that inside the tool?
Download Chairgun, it's very good once you understand how to navigate it.

https://us.hawkeoptics.com/chairgun.html

Here's an example of data generated to compare two different pellet shapes with all other criteria being equal:

Image

Re: GGDT/HGDT Request Thread

Posted: Fri Apr 26, 2019 11:41 pm
by lordBenio
I have notice that D-hall's website is down. Only reason I know, I would like to download the most recent HGDT program.

Re: GGDT/HGDT Request Thread

Posted: Sat Apr 27, 2019 6:28 am
by jackssmirkingrevenge
Not loading for me either.

Re: GGDT/HGDT Request Thread

Posted: Mon Aug 19, 2019 11:06 am
by Sear
Does anyone have a GGDT installler/exe file? I lost it on the old PC and now I would like to make some compressed-air mortar calculations. This tool was so handy!

Re: GGDT/HGDT Request Thread

Posted: Mon Aug 19, 2019 1:23 pm
by jackssmirkingrevenge

Re: GGDT/HGDT Request Thread

Posted: Tue Aug 20, 2019 2:52 am
by Sear
You are my hero, Jack! Thank you

Re: GGDT/HGDT Request Thread

Posted: Tue Aug 20, 2019 7:29 am
by jackssmirkingrevenge
au plaisir!