GGDT/HGDT Request Thread

[topelitemarine]

what value does GGDT use? Cm or inches?

[jackssmirkingrevenge]

It can use both, go on file -> configuration to change the units

[topelitemarine]

It can use both, go on file -> configuration to change the units

Got it thanks

[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).

[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.

[matti]

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)

[Cthulhu]

Thanks guys, I feel like an idiot for not noticing such a small unit error

[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

[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:

[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.

[jackssmirkingrevenge]

Not loading for me either.

[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!

[jackssmirkingrevenge]

voila

[Sear]

You are my hero, Jack! Thank you

[jackssmirkingrevenge]

au plaisir!