Build a VTOL

[Twinky827]

... Ok, I\'ve been trying to do this for awhile, but whenever I put my engine somewhere, it flips the jet over on takeoff. Same for landing. I ALWAYS put it at the center of gravity, yet, it still does it..

[GROOV3ST3R]

Maybe you should try 2 small engines on the sides or back and front?

[vexx32]

Aye. Use multiple engines (ideally at the very extremes of the aircraft) to keep it balanced during takeoff.

[RavingManiac]

RCS or thrust-vectoring is definitely needed to keep the craft stable during vertical takeoff, plus ASAS or Mechjeb.

Also, unless your center of lift is in the exact same horizontal position as your center of mass, moving upwards fast enough will cause the craft to tilt in the direction of the movement.

[SasquatchM]

Thrust vectoring in a must.. increase the throttle slowly untli the plane is bouncing a bit, then go just a bit more. It is pretty trick to get on to work without any RCS as well.

[GROOV3ST3R]

Well using stock parts its night on impossible although I would look into the RCS thrusters for providing the main lift force - it is only needed for a short amount of time either way. There have been people using those little things to propel themselves at extraordinary speeds, it could work provided you can activate them all at the same time and get enough fuel.

However, it is MUCH easier making a proper VTOL or at least a plane that is able to hover in one spot with the Damned Robotics pack. Using only the rotating mounts (and mechjeb\'s unmanned cockpit for crew safety, not actual flight ) I was able to build a successful hovering plane. It cannot VTOL due to overhang engines but it can hover and automatically too.

The trick was to find a good balancing spot on the plane. I could tweak it slightly but it worked for me.

Then you need to mount a standard Advanced SAS module on, preferably in the middle of the plane in order not to offset weight and to have some sort of COG reference. Then you need to take off in a conventional manner, turn the plane around to maneuver over land and level the plane. Then just wind engines down, activate SAS to keep the plane level and turn them around. Once they are in vertical plane, I found that keeping around 35-40% throttle for advanced jets keeps them nice and steady at the desired height. Should the plane start tilting forwards/backwards, just turn the engines in the direction of the tilt to cancel it out. For slowing the plane down, wind the engines down and angle them about 5-10 degrees in the opposite direction to travel at less than 30% throttle to avoid spinning wildly out of control. Thats a little guide to my contraption, rest is self explanatory. No RCS, only small amount of thrust vectoring and SAS to keep it level makes for an easy flight.

Controlling the engine mounts is surprisingly easy, just push the buttons in the pop-up menu or select hotkeys while in the hangar and use that.

Here are some screens:

In the hangar:

Turning using only angled engines:

Beginning to hover:

Hovering nearly dead over a fixed point:

I know that some of the challenge in that is missing what with going the easy way of modifications but it is a sure fire way to make a working prototype to test the behaviour of hovering planes untill you can come up with a stock-parts one.

If you want the craft file, here it is:

[kerbalgamer]

I have built a very good hybrid vtol it is good and all you need to do is have stable gear and avionics on I have made 3 sucessful vtols so far I will post the .craft in the space exchange some time

[Twinky827]

Thanks, but I still have trouble, even with 4 engines...

[GROOV3ST3R]

Did you try mine out? It does work, its a bit tricky at first but fairly straightforward once you get the hang of it.

And problem with 4 engines is that you MUST get them equally spaced out from the center of gravity. If you fail to do so, one side of the plane will bear more weight than the other yet you cannot moderate thrust to compensate for that. The simple throttle control of 1-for-all-engines means you are best off with a 2-motor contraption with motors either at the sides in the center or making a helicopter with modded parts. Eitherway, the thrust must be provided from either THE CoG or the point directly above it/either side of it. Any offset makes vertical take off a pain in the kerbal butt....

Just exactly how does your plane behave during take off? Which way does it pull?

You can always try putting advanced SAS on it, putting balancing wings on, activating it and then trying to take off slowly.

[Twinky827]

Yours is nice, but it cant take off or land.

[GROOV3ST3R]

Well... yeah but it can hover without tipping Ill build you one that can VTOL if you want.