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Old 05-04-2012, 10:55 PM   #1
goaowonk
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Default Specific Impulse of DGIV

I've been looking for the Delta Glider IV's engines Isp, and I havn't found it anywhere, only for the default DG (410^4s). Well, I could estimate it by calculating delta-v and delta-mass, but I'm sure that's a very unprecise way.
So, does anyone have it?
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Old 05-05-2012, 01:53 AM   #2
PeterRoss
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As far as I know DGIV has the same ISP of 4000 s (40000 m/s). You can use
Burn Time Calculator 2.32
to determine engine's ISP.
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Old 05-05-2012, 04:38 AM   #3
sorindafabico
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Also, you can change the ISP in "...Orbiter/Sound/deltagliderIV/Dg4config.exe". There are four options in the "fuel reserve" menu.

Last edited by sorindafabico; 05-05-2012 at 04:40 AM.
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Old 05-05-2012, 08:55 AM   #4
SolarLiner
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Quote:
Originally Posted by PeterRoss View Post
 As far as I know DGIV has the same ISP of 4000 s (40000 m/s). You can use Burn Time Calculator 2.32 to determine engine's ISP.
Nope. The GD4 Config tool edits the ISP by changing the engine (Mark I to Mark V) So it depends from the player's choice.
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Old 05-05-2012, 09:25 AM   #5
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Quote:
Originally Posted by SolarLiner View Post
 Nope. The GD4 Config tool edits the ISP by changing the engine (Mark I to Mark V) So it depends from the player's choice.
Nope Config tool can change its trust, not ISP.
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Old 05-05-2012, 10:37 AM   #6
sorindafabico
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Config tool changes BOTH thrust and ISP.

When you set up fuel reserve as "just ISS", DGIV ISP is lower than "trip to Jupiter".

"Just ISS" is 36000 m/s, "ISS and The Moon" is 44000 m/s. I don't remember the values to Mars and Jupiter presets.

Mark I-V are presets for thrust.

Last edited by sorindafabico; 05-05-2012 at 10:39 AM.
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Old 05-05-2012, 10:59 AM   #7
N_Molson
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Quote:
Well, I could estimate it by calculating delta-v and delta-mass, but I'm sure that's a very unprecise way.
If you use the Tsiolkovsky equation, you'll get a very precise result...

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Old 05-05-2012, 05:51 PM   #8
goaowonk
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Quote:
Originally Posted by N_Molson View Post
 If you use the Tsiolkovsky equation, you'll get a very precise result...

{image}
I meant I could use that formula with Ispg0 instead of ve, but it means that I need to get the values for delta-v, initial mass and final mass (delta-mass=final mass - initial mass) several times and then get Isp for each case. So then I can get the regression value... but my problem is this:
If I do several big burns, and take note of the three values, delta-v changes its increasing rate. If I do shorter burns (I've tried with 10s burns), delta-mass is too near to 0... that makes errors increase a lot.

Anyway, thanks for the help.

P.S.: I'd prefer not to use too many add-on MFD's, because they use the program's core instead of sensors or something like that, and are unrealistically precise and economic when maneuvering. Even Orbit MFD makes everything much easier...
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Old 05-12-2012, 04:34 PM   #9
Scattykat
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Here might be of help: http://www.strout.net/info/science/delta-v/ along with: http://www.braeunig.us/space/propuls.htm and: http://www.answers.com/topic/specifi...rocket_engines
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