Radially Attaching Aircraft to Spacecraft

[GreeningGalaxy]

Hey everyone-

I've been wanting to explore Eve a little better than is possible with rovers or kerbals, so I got out my standard long-range ship and added a couple of Aerospike-powered planes to either side, ending up with this.

The mission went reasonably well at first- the tanker was able to get a nice circular orbit despite the extra mass of the planes, docking of the regular lander went as smoothly as could be expected, and I pulled off some pretty sweet fiery aerobraking upon arriving at Eve with a speed of about 5 kilometers per second. Unfortunately, when I tried to use the planes, I hit trouble- the hydraulic ejection manifolds I used to detach the planes from the main ship eject from the main vehicle, but stay attached to the planes, which provides just enough extra mass and drag to make them really want to nose-dive unless the engine is throttled up very high and the control surfaces turned all the way upwards. I've been messing around with different decouplers, but nothing seems to work- I can't hold it from the rear because you can't attach anything to aerospikes, and there don't seem to be any radial decouplers out there that let go of both sides when fired.

So, does anyone have any tricks out there for this kind of thing? I can think of a few solutions already, but they all involve bigger planes or less efficient engines and I just want to know if anyone has a better system of getting aerospike-powered planes to Eve.

Thanks!

Edited June 3, 2013 by GreeningGalaxy

[CalculusWarrior]

The problem is that there is no radial equivalent of the decouplers that attach to both sides. Maybe you could use a Cubic Octagonal Strut, and use one of those, or even just a standard decoupler. I'll experiment with designs and post pictures as soon as I've got something working.

EDIT:

I made a test craft to showcase the different decouplers; I thought maybe the small decoupler would work, but as you can see, it didn't.

All the fuel tanks decoupled from the central tank, leaving nothing behind but some debris. However, when I tried the second method:

It decoupled cleanly, leaving only a Cubic Octagonal Strut on both sides. Since it has a mass of 0.005, I don't think that it should affect flight performance very much.

I hope this helps!

Edited June 2, 2013 by CalculusWarrior

[Snooze]

Have you considered docking the planes and ferrying them that way? Nothing stuck to the plane, smooth release, and you can bring them home or fling them at Laythe.

[M5000]

Yeah, the best way I'd suggest is to just use a docking port..

It will allow for re-use later, though, those planes don't look like they want to go to land and come back, but who knows?

[GreeningGalaxy]

Thanks for all the suggestions, everyone. I did think of docking, but docking ports don't want to go together face-to-face in the editor, and I'm somewhat unexcited about flying both planes up individually. Plus, the docking port still has mass.

However, I was noticing that the mass value for the small gear bay is actually a bit higher than that of the hydraulic detachment manifold, and gear has never given me trouble. Maybe I've got some other issue with the planes that makes them want to flip out? I'm not sure. I guess I need to run some more Kerbin tests.

If all else fails, I can re-engineer the ship to carry more payload and use bigger planes with spots on the back available for stack decouplers.

[bsalis]

The indicated mass value on the landing gear is wrong. They are much lighter.

My suggestion is to put a docking port on the tanker, then attach plane to it in VAB with an octagonal strut.

[Leyvin]

Thanks for all the suggestions, everyone. I did think of docking, but docking ports don't want to go together face-to-face in the editor, and I'm somewhat unexcited about flying both planes up individually. Plus, the docking port still has mass.

However, I was noticing that the mass value for the small gear bay is actually a bit higher than that of the hydraulic detachment manifold, and gear has never given me trouble. Maybe I've got some other issue with the planes that makes them want to flip out? I'm not sure. I guess I need to run some more Kerbin tests.

If all else fails, I can re-engineer the ship to carry more payload and use bigger planes with spots on the back available for stack decouplers.

What you will want to do is:

• Setup A Radial Port

• Attach The Docking Port

• Between the Space Plane and Craft Docking Ports, place the Blue (Non-Explosion Pin) Separator

• Make sure that the Space Plane is Kept Stable with the Structural Connectors

---

Now an alternative to this is actually to create an Interplanetary Shuttle Craft that you attach the Interplanetary Engine to the back with a Large Docking Port as they are incredibly secure.

[GreeningGalaxy]

What you will want to do is:

• Setup A Radial Port

• Attach The Docking Port

• Between the Space Plane and Craft Docking Ports, place the Blue (Non-Explosion Pin) Separator

• Make sure that the Space Plane is Kept Stable with the Structural Connectors

---

Now an alternative to this is actually to create an Interplanetary Shuttle Craft that you attach the Interplanetary Engine to the back with a Large Docking Port as they are incredibly secure.

Thanks!

Now that I see that it seems pretty obvious, I guess I just never thought of trying to use stack decouplers as radial decouplers before, just assumed it wouldn't let me attach the planes that way I guess.

I'll try that as soon as I can and tell you how it goes.

[CalculusWarrior]

Thanks for all the suggestions, everyone. I did think of docking, but docking ports don't want to go together face-to-face in the editor, and I'm somewhat unexcited about flying both planes up individually. Plus, the docking port still has mass.

However, I was noticing that the mass value for the small gear bay is actually a bit higher than that of the hydraulic detachment manifold, and gear has never given me trouble. Maybe I've got some other issue with the planes that makes them want to flip out? I'm not sure. I guess I need to run some more Kerbin tests.

If all else fails, I can re-engineer the ship to carry more payload and use bigger planes with spots on the back available for stack decouplers.

I have heard elsewhere that landing gear either has a much smaller mass or else is massless while folded up, but has the full .5 t when deployed. That might explain why it doesn't make planes flip out in flight.

However, it is entirely possible that your plane is inherently unstable in flight. Have you tried building a replica in the SPH and flying it? And are the centre of mass/lift markers lined up properly? I suppose it is hard to do that when the plane is attached sideways to a rocket, though

[GreeningGalaxy]

I did do extensive Kerbin tests of the plane (its mass and lift centers are in the right spots) with the only difference from the real thing being that I didn't test it with the decoupler attached to it. It should fly pretty well (and in all honesty it was doing fine on Eve, it just had to be throttled up way too high). I'll try a few things this Friday when I get a chance to play the game again.

Edited June 5, 2013 by GreeningGalaxy