Spaceplane help

[TerrificToby]

Hello all,

I have been experimenting with spaceplanes and have come up with a few designs however i could use a little help. you see, when i'm doing the test flight of my aircraft, i manage to get aibourne but my take off speeds are way too high. speeds like 144m/s and 126m/s. none of my take off speeds so far have been under 100.

I want to make at least one work so i'd appreiciate all the help i can get.

cheers,

Toby

[M5000]

What do you mean they're too high? Speed is good...

If you mean they're taking too long to get off the ground and you end up running out of runway or something, then just add more wings, your lift isn't high enough..That's the only thing that could really cause it to take too long to take off...

Else if you've already spammed wings all over and it's still not acting right, add more control surfaces, or add some if you don't have any.

[Vanamonde]

If you can arrange to make the front landing gear taller so that the plane sits nose-high on the runway, that helps generate lift for takeoff. Control surfaces mounted at the front and/or back of the plane will also help with rotating the nose, but don't overdo it because that can make the plane unstable. What do your planes look like?

[RoboRay]

It's not just how many wings and control surfaces you have, it's how they are arranged. The position of your landing gear is also a big factor on takeoff speeds.

Post some pics of your craft?

[Nao]

As Vanamonde pointed out hose high landing gear helps, or you can try moving existing main gear closer to center of mass. That makes more cool looking planes but, the trade off would be that it's easier to get a tail strike, so the higher the gear the better.

[bsalis]

If you can arrange to make the front landing gear taller so that the plane sits nose-high on the runway

Yes that helps. Also...

- have a larger ratio of control surfaces to lifting surfaces

- move the CoM closer to the CoL

The plane pitches up when the control surfaces move the CoL in front of the CoM. CoD matters too.

[RoboRay]

Having your rear landing gear too far back can make it almost impossible to raise the nose. Put the wheels just behind the CoM, but not quite so close that the nose tips up and the plane sits back onto the tail.

This is my preferred landing gear configuration:

The rear wheels are the pivot-point when you try to raise the nose, so the further forward they are, the easier it becomes to take off (so long as they aren't so forward that you tail-strike the runway).

Edited April 25, 2013 by RoboRay

[dueyx99]

hey there RoboRay, anychance you can show some more details on this SSTO? i'd like to try and build something like this, I suck for coming up with ideas, thanks.