NEAR spaceplane - not working?

[KITTYONFYRE]

There she is in all her glory. Never really built spaceplanes much with NEAR, as I haven't had it long. I have a problem with this thing though. When I take off (which is just flying off the end of the runway and pulling up so I don't hit engines - that's fine with me) I start my 45 degree climb and around 1,000 meters up, I slide to the right a little. I try to correct, and if I do get it back on track, it just slides to the other side. Using SAS does not help. After maybe a minute, I totally lose control and fall into the ocean. Why? I have flown SSTOs to minmus in stock, but never made one in stock or NEAR and flown it (even to orbit, I think).

Could it be drag from the shock cones? I have 6 per engine (which seems really high now that I mention it) and I placed them engine, intakes, engine, intakes.

[The_Rocketeer]

Can you post a pic of CoL and CoM also showing?

My first guess is your CoM is moving backwards rapidly as the nose tank drains first.

Also, I may be wrong but I believe you should add an engine after its intakes and not the other way around. This may also be the problem.

[KITTYONFYRE]

Can you post a pic of CoL and CoM also showing?

My first guess is your CoM is moving backwards rapidly as the nose tank drains first.

Also, I may be wrong but I believe you should add an engine after its intakes and not the other way around. This may also be the problem.

1. Uhhhhhhh.... Look again. Lol.

2. Hmm I thought it could be that, but I'm burning less than 10 untis of fuel in the time it takes to crash.

3. Maybe.

[GoSlash27]

I don't use NEAR, but sounds to me like your vertical tailfin is too small and not far enough back.

Best,

-Slashy

[DeMatt]

You do not appear to have ANY control surfaces that can act as a rudder. I do see RCS blocks, but I assume you're not using those in atmosphere. So you're totally dependent on your torque for yaw control - and you don't appear to have very much of that.

Try adding some vertical control surfaces, both on your tail and partway down your wings.

[Alshain]

Vertical tail fin is too small.

Your CoL needs to be a tad bit back more, your going to have trouble with it flipping end over end.

Not your problem, but you don't need 6 shock cones for each engine. You need 1 per engine. In NEAR/FAR aerodynamics you will reach the maximum speed of the engines velocity curve before you run out of air, unless your not piloting right.

[LaytheAerospace]

Tail fin is way too small, and you need a rudder. Also looks like you're also going to have CoM issues as your tanks drain. Keep in mind that they drain front to back, so your CoM is going to move steadily back. Make sure you've got a healthy distance between the CoM and CoL at all fuel levels, or you're going to have a bad time.

[The_Rocketeer]

1. Uhhhhhhh.... Look again. Lol.

2. Hmm I thought it could be that, but I'm burning less than 10 untis of fuel in the time it takes to crash.

3. Maybe.

LOL @ myself, ok but that's some serious camouflage.

Are you using the LV-Ns during takeoff? If so the rocket tanks will be draining too (unless you've hosed them - I looked but I don't see), probably more of the problem.

Vertical stabiliser's never been an issue for me, but I fly stock. Some of my aircraft have very small stabilisers.

[MarvinKitFox]

Your drag is ahead of your CoM, so any lateral instability will rapidly amplify itself. This is your biggest problem.

Your tailfin is a bit small, but should be ok.

Your rudder is ***WAY*** too small. (As in rudder, what rudder? we don't need to stinkin' rudder!)

[LaytheAerospace]

Vertical stabiliser's never been an issue for me, but I fly stock. Some of my aircraft have very small stabilisers.

It's a much bigger issue with FAR and NEAR (I presume, I've never used NEAR). With stock aerodynamics you could bolt wings on the SPH and fly it to orbit with enough thrust and air.

Your drag is ahead of your CoM, so any lateral instability will rapidly amplify itself.

Looks like it's behind it to me, but not by much, and it won't stay that way very long.

Also, the OP should probably scale back his ambitions a bit, and try a smaller plane to get the hang of how things work first. A quad engine plane hauling a pair of LV-Ns to orbit isn't the hardest thing in the world to build, but it's not all that easy, either. A 10t plane with a pair of rapiers mounted behind tandem FL-T800s is dead simple to build and fly, and is easy to balance the CoM so it doesn't shift as the tanks drain.

[Van Disaster]

Fin is way too small ( no rudder either? ), avoid adding things which are wider than they're long ( like the intakes not really attached to anything - stick those on the front of one of the long tailpieces if you have to ) because that is a way of making a high drag item in FAR, and also with a span like that the ailerons are probably going to cause a fair bit of yaw coupling. Jets are nerfed hard enough in FAR that adding too many intakes is pretty pointless - I was playing with stock parts yesterday & going over two per engine really didn't do anything useful, so you could just remove all the ones on the wings and add a couple of thin straight ones on the fuselage again if you find you can use a bit more air, and you've got a cleaner shape out of it too.

You really need to go over the craft in general and think "streamlined" too, the blunt nose is also not a great idea. FAR isn't as hard as people think, but it does pay to keep general aircraft concepts like smooth shapes in mind even when you're making something really odd.

[Voculus]

Ditch all the extra intakes. One shock cone intake per engine will suffice, and remove a ton of drag from the leading edges of your wings.