Can this get to an stable orbit?

[offstyler]

Hello,

I just started playing KSP and tried to build a plane, which can make it to an LKO, but my flight skills aren't that good, so if someone feels like trying out my plane and test it...just do it.

Action Keys:

1 - Toggle Jet Engines

2 - Toogle Aerospike

3 - Decouple Fueltanks

Yes, actually it isn't a SSTO, because it has two tanks, which can be decoupled.

Download

Some Pictures: http://imgur.com/a/YXksO

Thanks

Edited April 26, 2013 by offstyler

[astropapi1]

could you post some pictures?

[offstyler]

Added imgur link

[Zephram Kerman]

Well that's purdy! It looks a bit heavy for the number of engines. So I think with skillful piloting, you could get pretty close to orbit, but not quite. But if you remove some of the extra parts (lights, RCS fuel) it could get even closer.

I like how it has only one intake per jet engine. Lots of folks will tell you to add more intakes to radically increase performance, but I feel that's unrealistic (or perhaps even a bug exploit). SSTO spaceplanes can work without "airhogging", but it's difficult.

Heck, in my opinion, any Kerbal plane that is stable enough to get off the runway and can go suborbital is an achievement. So congratulations! You've learned a lot to get this far.

[offstyler]

Well that's purdy! It looks a bit heavy for the number of engines. So I think with skillful piloting, you could get pretty close to orbit, but not quite. But if you remove some of the extra parts (lights, RCS fuel) it could get even closer.

I like how it has only one intake per jet engine. Lots of folks will tell you to add more intakes to radically increase performance, but I feel that's unrealistic (or perhaps even a bug exploit). SSTO spaceplanes can work without "airhogging", but it's difficult.

Heck, in my opinion, any Kerbal plane that is stable enough to get off the runway and can go suborbital is an achievement. So congratulations! You've learned a lot to get this far.

Thanks, that means a lot to me

I think i'm going to tweak this now with this additional knowledge.

[Jason Patterson]

I'd be surprised if that couldn't make orbit. It's probably got excess jet fuel, but otherwise it looks perfectly fine to me.

I'll give it a whirl.

ETA: As it stands it has a balance problem. Even if I set the fuel to only drain from the rear tanks, the center of mass shifts toward the back and the plan becomes unstable, eventually nosing up and flipping out of control. I moved the wings back significantly and it was much more stable as a result. I also replaced the ASAS with avionics (because I'm not a great pilot and avionics is basically piloting for dummies.) I only had time to give it one good go to get into orbit, and I came up about 500 m/s short. I suspect that if you cut some jet fuel mass and/or added another pair of intakes you could get it into orbit. If I have a chance I'll try again tonight to see if I can make orbit only by moving the wings.

Edited April 26, 2013 by Jason Patterson

[K^2]

The Good:

1) Decent stability. I had to transfer fuel from the rear jet tanks to front tanks in flight to make sure it keeps flying stable, but there were no catastrophic control problems.

2) The aircraft was able to land after a failed attempt to reach orbit.

3) Bill survived. He asked me to thank you personally.

The Bad:

1) You generally want to have two intakes per jet engine. Consider using a structural bi-coupler in the front to have two intakes where you have one.

2) Too much jet fuel and too little rocket fuel. One jet tank per engine is all you need. The best way to fix this is to leave one jet fuel tank where you have two sandwitched between two FL-T200 tanks. It will give you the same overall length and trade the weight of jet fuel for rocket fuel you need to make orbit, while keeping the entire thing way more balanced. You will need extra fuel lines to connect these. I'd just feed them to central tank. That will result in them getting drained before your drop tanks, but it's better than loss of stability you'll get from any other configuration.

The Ugly:

Drop tanks. I have nothing against them in principle, but this particular configuration shifts CoM up until they are dropped. As craft uses up jet fuel, that becomes more significant. At 16k and 600m/s I had to do a lot of fighting with controls. If you must use drop tanks, make sure they are in-line with the rest of the craft. In this case, I'd shift them to wing-tips. You might need to add struts to make sure they stay put there.

[Jason Patterson]

Still coming up short getting to orbit. I suspect that losing a couple of tons of jet fuel would do the job, and certainly if you add another pair of intakes and drop jet fuel. I was topping out at around 850-900 m/s near 18km altitude before starting the rocket. It's almost surely possible to go significantly higher and faster by throttling down and burning off most of the jet fuel.