4 engine V/STOL

A rough sketch of the aileron section of the compound flap wing for the 4 brushless set up.


At just 24" span the wing is going to be quite crowded inside as apart from the 4 motors and ESCs there will be 5 servos as well.
The fixed part of the wing with its unusual inclined spar and triangular balsa flanges.

The wing skin is 2mm Depron.

I have feeling this is going to be even harder to fly that the much simpler 2 motor version!

Actually its the other way round. Flaps bottom hinged, ailerons top.

Progress so far.

Note the flaps are in one piece right across the wing.

The first flap section driven by 2 servos will drop to a maximum of 45 degrees, taking the ailerons and their servos with it.
The second flap section with its own servo can drop another 45 (so up to 90) but not the ailerons. The 3 flap servos will move simultaneously.

I am hoping the fully shrouded first section flap hinge will ensure the prop wash remains more or less attached to the surface so the ailerons remain effective even when full flap is deployed.

If it proves to have adequate roll control some aileron droop could always be mixed in but I doubt it will be necessary.

very clever stuff, i watch with great interest

Thank you gentlemen for compliments - I think!

As with my usual lightweight stuff everything will be 'built in' so you have work forwards from the trailing edge.
So 2nd flap and ailerons complete & servos (3.7g) mounted in the 1st flap (& tested!) so its ready for the top skin to go on.

The hardest bit will be the front part as all the heavy bits have to be added before the top skin makes a rigid box.

As of now I have only the vaguest idea of what the rest of the plane will look like!

First section flap complete with 3 servos buried in it.

Two 5g servo to move the first section flap mounted and tested.
All the surfaces are now joined and hinged.
Next to add the motor mounts and ESCs.

I suppose I had better start thinking about the fuselage and tail!

Motor mounts with the flaps resting in the full down position.

The mounts are made of 3mm particle board (the sort of thing IKEA use for the back of kitchen cabinets!) as it glues well and takes a miniature self tapping screw better than ply.
Each is supported by a short nacelle of 2mm Depron sheet.

Like this the wing with 5 servos weighs 69g. With the motors and ESCs 170g. I am aiming for 380g (13.5oz) all up with a 2200mAh 2s.

The motors installation.

The 10A ESC mounted.

This is repeated 3 more times and all wired up.
Left

Centre

Right

To save weight and space all the connections are soldered. There are 46 in total in the wing.
The only 'connectors' will be in the fuselage to the battery and radio.
It has all been tested so I have to hope it all keeps going as any sort of repair will be virtually impossible!

Might sound like a daft idea but how about getting two pusher prop's and running 2 of the motors backwards?
Just thinking about cancelling out the torque.
Have I been hitting the loopy juice too much?

Pol.

Pol
It does have handed props, in fact everything was determined by the availability of a set of 4 L&R 5x3 3 blade props.
Literally buy the props and then design a plane to use them!

The fuselage complete with the elevator servo stuck on the end of the boom.

It weighs 23g
or put another way the wing weighs 10 times more than the fuselage!

Quorneng wrote: Pol
It does have handed props, in fact everything was determined by the availability of a set of 4 L&R 5x3 3 blade props.
Literally buy the props and then design a plane to use them!

I don't know about VSTOL .... you're building a bloody helicopter.
God help us! ... this forum attracts its fair share of nutters.
Classic fun though!

Pol.

Only just 'balanced' together to see what it looks like....er.....rather bizarre?

When (or if!) the flaps go right down its anybodies guess as to whether the tail plane will have any effect at all!

Have to wait for the radio to arrive before it can go any further.

That looks like it'll flip straight over onto its back ... I can't wait to see this.

The final task before it is fixed together permanently - fix the servo links.
To save weight there is no adjustment just made exactly the right size, fortunately not so difficult with soft steel wire from a paper clip.

Having two servo driving the same control surface is not ideal as any variation in the linkage geometry and the servos fight each other. A bit of linkage slop should cure it.