It Appears to be Powered by Witchcraft

[Sauron]

But seriously, this plane is absolutely ridiculous. It has a glide ratio of I don't even know (this may be the result of KSP's aerodynamics--not sure. Enlighten?). It took me almost 20 minutes to bring it from 3000m to landing--it just insisted on going forward at about 150 m/s and not stopping (I added the air-brakes after that). With that kind of lift, I reckon this thing could get a respectable way around the planet. For an (almost) first try at planes, that's not half bad, IMO. Also, at only 13.5 tons (and it could really be a lot lighter. Most of that fuel is unnecessary, and I could easily ditch one, or maybe even 2 of the engines) it'd probably work fairly well on Laythe as well.

That said, it is a first try, and some pointers to make it a bit more controllable or efficient (or turn it into an SSTO ) would be very much appreciated. I'm fairly pleased with the aesthetics--keeping them as similar to the current design as possible would be a plus.

Mods used:

-Reaction Wheel Mod (beats tacking on random probe cores)

-Taverio's Aerospace and Pizza

-B9 (a little bit)

If there's any interest, I can make the .craft file available.

Edit: It appears that the revised version has a less enormous glide ration. On the other hand, it also seems to be hugely more controllable. Ditching the diagonal tailfin seems to have been what did it. I might be able to lose all those compressed air thrusters.

Edited June 28, 2013 by Sauron

[Sauron]

Actually, I've got a request to add as well. How the heck do you get something like this into orbit (WITHOUT making it an SSTO)? It's too unbalanced to launch even on significantly overporwered rockets. Any thoughts here, guys?

[deker13]

add struts to be balancing out the mass. you know, like sticking out a stick? that might work. just sayin.

[Bioman222]

Ah.... the inifinite glide phenomona... good times, good times.

[deker13]

thought it was only in 0.13. guess not.

[Rune]

Actually, I've got a request to add as well. How the heck do you get something like this into orbit (WITHOUT making it an SSTO)? It's too unbalanced to launch even on significantly overporwered rockets. Any thoughts here, guys?

Put the rocket on top of the payload. The reason everybody finds so difficult to launch winged vehicles with rockets is that you want the center of lift behind the center of mass, not the other way around. So instead, it usually happens that you are trying to fly an arrow going backwards, with the fins on the front, and of course it then wants to tip over.

You could also add more lifting surfaces to the rocket, but if you say this has a lot of lift, it will end up being a lot of parts to do so. I'd go with a "T" design, with the payload hanging from a big core tank, the engines on pods on the sides of it, and side boosters attached to the top. It will also be more structurally sound if it's a tractor system (stuff works better at tension regarding structural strengths).

Rune. Basically, a rocket also has to be able to fly straight by being aerodynamically stable, even in KSP's physics.

[Sauron]

I solved the orbiting problem. Because the wings are so big, and because plane and rocket controls don't always agree when mixed together, launching two planes at the same time so the flaps cancel each other out in the first 30km of the launch has been the easiest solution to the problem so far. I was going to bring two of them to Laythe anyway, so better to do two launches in one. It's not as if 13 tons (or less--I trimmed the design further to around 10-11 tons) x2 is challenging mass-wise

I've been measuring the glide ratio it gets, and have mostly found that Kerbal engineer tends to lie about your vertical speed every now and then. I have an absolute lower bound of 20:1 (probably closer to 40-50), but that's without repeatedly pulling up and diving. If I had an effective way to measure the distance between landmarks on Kerbin I'd have a better idea. Also, this is one *very* stable plane. Completely idiot-proof, and I'm a dreadful pilot (I think I'm going to run with flying wings at this point. It seems to be working well for me.) It doesn't freak out at the slightest tap of a key, it's well balanced (not perfectly--it rolls a little bit when I'm yawing on account of the slightly angled stabilizers at the end of the wings, and it's very slightly rear-heavy. Neither of these things have much impact on the actual flying). Also, it can land backwards. Don't ask.

However, my experiments at making it into an SSTO seem to be running headfirst into the mass death-spiral. What's the best way to approach this. Also, how should I configure my jets and fuel? What kinds of ratios work?

Edited June 30, 2013 by Sauron

[Rune]

However, my experiments at making it into an SSTO seem to be running headfirst into the mass death-spiral. What's the best way to approach this. Also, how should I configure my jets and fuel? What kinds of ratios work?

If it is because of flameouts, it's nice to know that the last engine you place while building will flame out first. So go for uneven number of jet engines, and place the center one last so you have a warning when you are courting disaster. I usually use less than 150l of fuel for each jet on planes, and less on VTOL's. Also, T/W on jets of about 0,5 for winged stuff, and on rockets it really depends on how much you airhog: you can circularize on ions if you spam intakes to fly on jets until 2,200 m/s, but you want over 1 T/W is your cutoff speed is under 1,500 m/s.

For beginners, that's two LV-909's for each jet engine or thereabouts. And it is recommended to start with single-jet small SSTOs.

Rune. Now go run some numbers!