Burn time calculation

[george7378]

Hi all,

I am having trouble with the equation:

(ISP x fuel remaining (KG)) / thrust (N)

I have the following values:

ISP: 4.697 kN*s/kg
Fuel: 75.58MG
Thrust: 1.052MN

I get 337.4S burn time, but this brings me short (in the IMFD BV/AB screen)

Thanks.

 

[Urwumpe]

It is remaining burn time, for calculating how much burn time you have left in your tanks.

For a maneuver, you need to calculate over the rocket equation:

Initial mass*(1-e^(-DV{Maneuver}/ISP)) * ISP/ Thrust

 

[Nemoricus]

My only advice is two-fold.

First, fiddle with IMFD's values and see if you can't come up with a plan that you can burn.

Second, if that doesn't work, and even if it does, just plan to include a number of midcourse corrections.

EDIT: Urwumpe, IMFD calculates the length of the burn in seconds in addition to giving the total delta-v. Calculating the burn time available is therefore a quicker to see if you can use the plan.

 

[Urwumpe]

EDIT: Urwumpe, IMFD calculates the length of the burn in seconds in addition to giving the total delta-v. Calculating the burn time available is therefore a quicker to see if you can use the plan.

Yes, but I meant my post as general mathematical solution.