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working on VTOL STOL delta canard twin prop puller.

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Working on full size plans . I have a spec, scale plans, source and spec of all components.

Wondering if prop pull-through air is enough to get STOL front lift from a standstill. I have set more than 50% of the front canard as elevator.

Front is about 1/3 wing area.

Props 9x5 sit about 40mm behind the front wing.

Thrust-weight ratio about 4:1

Wing loading 52 oz/sq ft.

Span = 34 inches

Weight est to be 1 kg

Electric, 4S, 4000 mAh, 108 amps at launch.

As a STOL, this is possibly prone to initial pitch-down.

If the huge elevators don't work, I can add a extra set of elevators behind the props, in line with the front wing,which is raised

90 mm wrt the wing.


I am 65 years old, retired,just restarted flying models hobby, my first RC.

It is to have a flight controller running Ardupilot, so well nannied-up.

There is a further revision not shown on the plan view, to the front wing.

plan 2-12-20.jpg

profile 2-12-20.jpg

Edited by OwenN
extra detail
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further thoughts on mounting an elevator over the wing leading edge.

1) the neutral position of of the new elevator will be affected by the flow over the wing, so it will not be in sync with the front elevator. This causes control problems.

could this elevator replace the front elevator?

2) an elevator over the wing gives a slot effect, and squeezes flow over the wing.

What effect does this have on lift and rear control surface loading? The rear elevons are powered and gyro stabilised as part of the pitch/roll system.

It wouldn't be good if this was a real plane with cable operated surfaces.


Is there a better way of moving the instantaneous AC forward?

The main wing AC is 50mm back from the combined AC

I am planning to put the COG right on the main AC, and rely on gyro stabilisation to smooth out any pitchyness.

The main AC is 100 mm back from the props.

I want the aircraft to blow up and back under static elevator, chopping elevator as it comes past 45 degrees, then gyro stabilise and launch.

Actually the rear will be off the ground unless full up-elevon pins it down.

Once up to 40 mph, which should take about 5 seconds, and 50 meters, full front wing authority should be established.

In fact, turnover can be initiated at much slower speeds due to elevons and elevators adjusting trim.

A plane that would normally stall, will fly really tail down at a very low speed, with enough thrust, then flatten out as it gains speed.

Horizontally this should only take about 2-3  meters.

Any more ideas or comments?

I have seen a model flying boat take off on grass in about a 1 metre slide, with one high mounted motor, so it doesn't take vast amounts of thrust.

mind you, that had half my wing loading.

I just don't want the rear to lift off, and the front skid to drag.

It may not run straight.


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Thinking about getting partial blow-over from a standing start: holding the rear down with the elevons, and setting the COG right back, plus the enlarged front elevator, should be enough to

get the effective AC in front of the COG. I shall try it. It would be neat if I could get a fairly conventional aircraft to act sort-of quadcopter-like on launch, without

being a full tailsitter.

Also landable in a breeze-sideways movement does not make for good tailsit landings. Mind you, ardupilot probably "has an app" for that! (station-holding).

Edited by OwenN
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