is it possible to build an SSTO with J-33 weesley?

[scavenger]

I guess it is obvious for most of you but I need to be 100% sure

thanks

Edited June 24, 2015 by scavenger

[Empiro]

Yes, but possibly merely because of the fact that you can build an SSTO with no jet engines at all. The problem is that with the basic engine, you don't get more than 300 m/s speed, and can't climb more than 10km or so. That barely lowers your delta-V requirements (and probably won't even offset the mass of the jet engine).

[rofltehcat]

You'd probably have to figure out what energy/work is larger: Dragging the jet engine, wings and intake to orbit and beyond. Or climbing to 10k/300m/s. Probably isn't worth it.

[selfish_meme]

I guess it is obvious for most of you but I need to be 100% sure

thanks

I tried building a rocket only ssto the other night. I used half my fuel getting to 10km, so it might be worth it.

[scavenger]

yep then i need more science to unlock the rappier and all

thanks folks

[Wanderfound]

Yes, but it usually isn't worth the trouble.

OTOH, a rocket-boosted Weasley makes a good early-game suborbital tourist ship.

[ajburges]

Also is an easier way to hit high altitude survey sites.

Ignoreing drag, 300 m/s at 10 km gives you 474 of the 2462 m/s needed for a hohmann transfer orbit to 70 km. That leaves you with a dV requirement of 1987 m/s minus losses.

Compare to a hohmann transfer from surface: 0 m/s at 0 m gives you 174 of the 2492 m/s needed for a hohmann transfer orbit to 70 km. That leaves you with a dV requirement of 2318 m/s minus losses.

Finally for reference, 1 km/s at 20 km is 1174 m/s of the required 2432 m/s; a 1258 m/s deficit.

Basically, for a hybrid SSTO, you need to craft a scenario where (wings,) aerobic engines, and jet fuel costs less than the extra rocket fuel (plus tanks and engines) needed to reach the edge of the aerobic flight envelope. For basic jets, that's about 400-500 dV. Not a lot of margin to work with. Other jets work because that margin is about 1100-1400 dV. That's a solid third of orbital dV requirements!

Altitude saves you tens of dV, horizontal velocity is direct payment of dV costs.

[KarateF22]

Yes, but it usually isn't worth the trouble.

OTOH, a rocket-boosted Weasley makes a good early-game suborbital tourist ship.

If you only need to get suborbital a single Kickback with thrust limited should do the job, and be cheaper.

[Streetwind]

If you only need to get suborbital a single Kickback with thrust limited should do the job, and be cheaper.

The Kickback isn't exactly "early-game", though. By the time you have enough science to unlock that, you're not doing suborbital tourist missions anymore. Besides, the plane will recover for 100% minus fuel costs, while the kickback is either lost or, if recovered via chutes, will recover for less than 100% (as is the capsule(s)).

[cantab]

Probably possible but not easy. Back in 0.90 FAR I did a Basic Jet spaceplane. FAR then gave the Basic Jet a similar top speed, but I was able to climb to a rather better 16 km on it before lighting the rockets. Whether it's *useful* is another matter mind you, it could easily have an inferior payload fraction and cost-per-kilo-to-LKO when compared to a good regular launcher.