Flight Question Just achieving a fuel-efficient orbit

[unknown_orbiter]

Hello Orbiter community, me == back . I have a question. What is the absolute BEST and most FUEL EFFICIENT way to achieve orbit in a delta glider? Every time I end up with around 35% fuel remaining when all is said and done. Even when I am able to achieve a circular orbit at my initial MECO I am still looking bleak in my tank. I have tried ascending at 30 degrees AoA then leveling off at 10 to extend my orbit. I have also tried going 70 degrees A0A and then gradually leveling off. I always takeoff heading east (090 degrees). Any help? Thank you!

 

[iam_inorbit]

For Fuel, why don't you use the Fuel Mfd you can get it from orbithangar, or you can get fuel anytime in scenerio editor. mine too burns a lot of fuel when going in orbit tblaxland advised me which i am forwarding it to you.

Happy orbiting
iam_inorbit

 

[Zatnikitelman]

What I typically do is start off ascending at 70 degrees horizon relative. Then gradually bring it down to about 30 degrees at 100km. At that point, I burn till I establish an ApA, then I try to maintain 0 vertical velocity.
However, even the DG is limited. Use Tsiolkovsky's equation in reverse to figure out the minimum fuel needed to reach orbit in the DG:

total_mass/e^(dv/ve)=mass_remaining
total_mass= maximum propellant and dry mass of DG
e=Euler's number
dv=deltav (9-10km/s good value for Earth Orbit)
ve=Exhaust velocity (ISP in seconds * 9.80665)
mass_remaining is dry mass plus remaining fuel mass

 

[RisingFury]

9 - 10 km/s delta-v will get you into a quite eliptical orbit.

 

[unknown_orbiter]

thanks!

 

[Zatnikitelman]

9 - 10 km/s delta-v will get you into a quite eliptical orbit.

If you're going strictly from a gained velocity standpoint. However, don't forget the atmosphere hampers acceleration as well as any acceleration pointing away from the velocity vector. This is known as gravity drag. So when designing a launch vehicle to get x payload of y mass into orbit, you have to compensate for atmospheric, and gravity drag which adds between 1.2 and 2.2 km/s needed dv to your vehicle.

 

[Sky Captain]

It is possible to put default Delta glider in 200 km high circular orbit with 58 % fuel still left. To do that climb steeply to ~25 km then pitch down and use elevator trim to maintain roughly 100 m/s vertical speed while accelerating to orbital velocity. That way you will use atmosphere to provide lift and main engines only to gain speed.

 

[EtherDragon]

It is possible to put default Delta glider in 200 km high circular orbit with 58 % fuel still left. To do that climb steeply to ~25 km then pitch down and use elevator trim to maintain roughly 100 m/s vertical speed while accelerating to orbital velocity. That way you will use atmosphere to provide lift and main engines only to gain speed.

Generally, the most efficient way to orbit in winged air-craft is to use the atmosphere to gain life/altitude, and rely on the engines for tangential velocity.

 

[RisingFury]

Generally, the most efficient way to orbit in winged air-craft is to use the atmosphere to gain life/altitude, and rely on the engines for tangential velocity.

Yes, but you have to penetrate the thick part of the atmosphere first or else the drag is gonna spend a lot of your fuel.