Spaceplane designed to take off and land in vertical position?

[Kidneythump]

I had an idea of making a spaceplane that takes of and lands like a regular rocket but with the added capability of regular flight, does anyone got any experience with this? So far the liftoff works like a charm, it's the landing bit that's troubling me, the plane starts to flip over and I end up having to resort to RSC to keep it vertical but even then some forward or backwards motion makes it nearly impossible to land, I'm guessing the wings have something to do with this? Sadly im about to go to sleep and cant be bothered with starting the game again and taking a picture so that will have to wait for tomorrow but in the meantime any help would be appreciated

[Shrike42]

This should only be a problem in-atmosphere, so I suggest using parachutes. Make it so they deploy from an action group so you can reuse them.

Kerbals in EVA can repack the parachutes if they're close enough, so this would let you land your craft like a rocket on worlds without an atmosphere, and drift gently down on worlds with an atmosphere.

[Spaceisbeautifulul]

Whoops, misread your question, forget this post.

[Van Disaster]

I presume "land vertically" doesn't necessarily mean it has to land on it's tail - in which case you could just use some small down-facing engines ( or specialist rotating VTOL engines, there's a few in the spaceport ) enough to control your final descent point. Wings don't work too well in reverse, no, nor does the fact you have to deliberately stall the plane if you're attempting to descend backwards in atmosphere.

[Phenom Anon X]

**Edit: Gah!! I may have misread your post topic, sorry!

Yep, it can be done!

I'm not sure if I've prepared enough documentation notes with my personal experiences in this, but while designing my stock shuttle, I performed numerous tests on the hull before working on the engine design.

First, it sounds like you have a Center of Mass and Center of Lift issue. ( Referred to as CoM and CoL here on the forums and abroad ).

Typically, I've tried to align the two to be as close together as possible. This can be tricky and is purely based on individual design of each craft you make, so take that under consideration. Don't even think about thrust until you make your plane a glider. I had to do this with my shuttle because when I come in for re-entry, I'm unpowered and have a 17 ton glider. It just has to work in order for me to continue on with my goals.

For CoL, Look very closely at your wings and design them with symmetry snap turned off to fine tune your wing surfaces. I have found this to be helpful for me, so your milage may vary. I'd say give it a try. Also, use the intended parts around their intended design, or at least try as much as you can with the limited parts available in stock.Less pretty designs, but for practicality, it just works. The same principle can be applied to mod parts as well.

Use the CoL tool to make sure the lift is generated at the wings and not the tail or nose. What's worked for me so far, is lift generated at or near center of my current wing design or at the very least, as near as possible to the greatest surface area that lift is applied. You just have to visualise it.

For CoM, it's again, craft design dependant.Certain parts will change certain attributes, so you may or may not need to adjust your part location a bit to get the desired CoM your looking for. Too much to the rear, and no matter how perfect your CoL is, the mass at the rear will cause you pitch up, putting you into a backflip on the slightest maneuver. Too far to the front of your plane, and your fighting the controls to keep the nose up, despite your thrust vector and lift profile.

I suggest experimentation with with your engines attached, but powered off for full testing purposes. Send your plane up with a standard rocket launcher, get a good altitude, pitch your rocket with plane attached to a heading of of 90⁰, get to vertical flight and decouple the rocket in such a way that it doesn't interfere with your plane what-so-ever. Coast, as far you can while keeping the plane level. Conduct simple pitch, yaw and roll maneuvers to examine it's flight characteristics.

When you land your glider properly in controlled flight, your ready for engine design.

The trick with engine design is to make sure your thrust is firing right through your center of mass. Toggle both in the SPH or VAB accordingly. Now you need to decide how many engines. !, 2, 3, 4? Every engine you add will change the way your plane handles in flight. Start with one in the middle, fly it for a while, then try 2 and so on.

I'm not an expert in Spaceplanes, but I've learned this information through trial and error with my stock shuttle design in various configurations with jets on or off, counter weights simulating engines for glide tests and with a full on external tank, decoupling and landing the shuttle on the runway. Orbit is a ways off yet for me. (65km altitude so far though).

I'm sure the more experienced players here will have far more valuable feedback than I could ever possibly dream of but I hope my small contribution puts you on the right path to success.

Good Luck!

*Edit: I forgot mention that if you'd like to see me conduct some tests on my redesigned shuttle, send me a PM so we can arrange a good time for broadcast on Twitch. I'll see what I can do. I swapped out the tailfin for a large delta wing and have to conduct glide tests again.

Edited June 11, 2013 by Phenom Anon X
Addendum: Twitch

[Markus Reese]

I did it, and quite enjoyed it. The pics are from way back a few versions ago, but the principles still work and is more effective with the increase in radial engines and control toggles. They are fun to fly and fun to land. I have a design that I am working on, but with another project to go it isn't finished.

Anyways, the pic is landed on the moon, but it is tested on kerbal first for function. Here are main concepts to remember.

1. Balance engines

Build main components in SPH. Just adjust your vertical engine positions until it can maintain balance so thrust prevents pitching beyond what command module can handle. With some forward motion, the wings can help with low-speed landing. Much like a harrier or helicopter. They can land perfectly vertical, but do best with some forward motion.

2. Plan for fuel usage

Make sure that your front and rear engine share the same single fuel tank, each have their own tank the same, etc. Make sure that as fuel burns out, it won't shift weight. Best test is to use a structure pylon to hold it down and test after doing original balance test. Burn down fuel to mostly empty and then release the clamp, see if still balanced.

3. Make use of the new control hotkeys

Toggle them engines on and off. In the old days, I would have no horizontal engines until I jettisoned the verticals. This way, you can lift off, and use a key to toggle now. In landing, have main flight engines that turn completely off at centre of your vertical lift. This way as fuel drains down, weight doesn't shift. Have a secondary engine to offer horizontal thrust or use pitch to control. I prefer using pitch, but in atmo, you will want the horizontal thrusting to make it easier.

Anyways, VTOL are really fun and must be built in SPH, but you can transfer them to VAB if you need to launch them for other planets. To do so, open your save file location and copy your ship file from SPH to VAB. Then open the file, change the = SPH to an = VAB

Edit: With mods, you can have engines with different thrust profiles. That way, you can control balance and pitch with throttle. Have some without ramp up, then a second to counter imbalance.

Edited June 11, 2013 by Markus Reese

[bsalis]

I had an idea of making a spaceplane that takes of and lands like a regular rocket but with the added capability of regular flight, does anyone got any experience with this?

Yep - plenty. For a tailsitter like this, all you need is legs on the back, which is the obvious bit.

If you are having trouble landing, put some parachutes at the front (near the cockpit for easy re-pack), then pull them when you are travelling slow and over the spot you want to land. They will keep you upright, then apply jet or rocket thrust as appropriate and needed to touchdown softly.

Works a treat!

[Markus Reese]

Oh, a tailsitter XD! Yeah, that is a bit more of a can of worms.

Problem is planes only like to fly one direction, so when stable flying in atmo, it wants to flip around when landing. Your key here is the drogue shoots and cut your velocity before going in for the landing. Do so as follows.

1. be sure you can maneuver at lower speeds.

2. Come in on a normal glide path

3. Pitch nose up into a stall

4. When you start to tail stall, engage your drogue shoots to control decent and land like a rocket.

Now in space, a tailsitter is easy with no atmosphere to spin you out.

[DeathAdder01]

a spaceSHIP?

[Kidneythump]

Ok update!

I am currently testing out my design with different shoots but im having trouble with the plane tumbling out of control even on the way down, this is how it looks:

I'm totally unable to control the tumbling for some reason

The parts are from the B9 Aerospace pack

Oh and just for the record, it works really well otherwise, i can do a orbital hop and land at ksp again when it got wheels instead

Edited June 12, 2013 by Kidneythump

[Markus Reese]

Hmm... not familiar with the parts you are using, but not sure why it wont work for the parachute landing. Only thought is if the drag and lift from your wings are more than the parachutes. Once at stall and deploy parachute speeds, it should stop spinning. Main thing is just needing to keep the speed low. However the 7.9m/s I think I see in your screenshot it should be perfectly vertical... Sorry I cannot help more.

[Kidneythump]

Hmm... not familiar with the parts you are using, but not sure why it wont work for the parachute landing. Only thought is if the drag and lift from your wings are more than the parachutes. Once at stall and deploy parachute speeds, it should stop spinning. Main thing is just needing to keep the speed low. However the 7.9m/s I think I see in your screenshot it should be perfectly vertical... Sorry I cannot help more.

Well thanks anyway, the funny thing is it's stable when the drogues initially deploy, then the nose starts to dip ever so slightly and then rights itself using RCS thrusters, this movement increases the closer to ground it gets until it starts flipping uncontrollably

[bsalis]

Ok update!

I am currently testing out my design with different shoots but im having trouble with the plane tumbling out of control even on the way down, -snip-

Hmm, not sure...

On Kerbin at least, try going into a vertical ascent, then throttle down. Now hit the chutes just after you stop and start falling backwards.

When i used chutes, i also didn't use RCS ... i was mostly hands-off controls, just using ASUS a to dampen out swinging as the back crossed the green retro marker.

Also, are you using FAR? Since that reduces drag which i don't think will help.