Saucer shaped vtol coanda effect multicopter

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karoliina.t.salminen

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I have been thinking about vtol concepts out of the box since they would have their place in aviation, a gap currently unfilled.

If we forget issues of combustion engines and consider an electric vtol. With today's batteries outcome will not be that useful, batteries are too heavy, but there are promising battery technologies coming within a decade or so if they are successful.

I have been thinking about stol plane stol takeoff and landing where the plane stays in the air with the lift augmented by the prop stream. Then I was looking at coanda effect. It is about the same thing as what happens on top surface of a wing and the boundary layer is attempted to be attached to the bending surface. The problems with coanda effect demonstrators seem to be related to detaching boundary layer.
And one boundary layer control method is suction. What it you would combine the propulsion, blowing and suction in circular shaped body:

I was at first thinking about blades outboard of circular body like this blog post:
DESIGN|A|PLANE: Idea: Helicopter with the blades extendeding from the outer edge of a lens shaped lifting body

Then I figured it might not be the optimal solution. What if you would have ring of ducted props around the circular body providing suction to the upper side and bent inwards on underside so it would be effectively blowing on the bottom surface. In other words simulate condition of forward movement of half airfoil without foward movement. The lift would not rely on the propellers like in quadro copters, but instead would take advantage of the lifting body.

Since the props on the outer rim of the aircraft would have small inertia and the response speed of a small brushless electric motor is fast, it would be quite possible to make software stabilization in hover for this kind of vtol aircraft.

To get forwards, there would need to be possibly separate drive motors & fans on upper surface so the circular lifting body could travel at positive angle of attact and would behave like a very low aspect ratio wing on cruise (not ideal airfoil though because leading edge and trailing edge has to be sharp for symmetry). Not the best for cruise efficiency, but at least cruise would not depend on vertical lift from the multiprops. And also the whole idea of this kind of vtol would not be to travel long distances, but instead take off and land where aircraft can't. Ideally lifting off directly from one's frontyard and landing on airport to get to a non-vtol airplane to cross long distances. So even as small as 60 km range would be already quite useful.
 

topspeed100

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I sorta like saucer shapes...I have been throwing a lot of different kinda frisbees this year and once managed to get it really soaring at 126 meters...world record at MOJAVE this year is 255 meters in strong winds. Normally a 100-110 meters is a long throw. The shape and weight and material all have an effect on the flight...and of course initial velocity, spin and direction ( tilt, angle and bearing ). I once stood really close on the path when a friend threw the disc at the basket...and the enermous pressure wave underneath the disc was a great sensation. I never had tought about it..but a 175 gramm disc actually has quite a huge cushion underneath as they fly...especially in approach discs...F=ma.

I have a feeling VTOL systems always need more force...or am I wrong ?
 
F

fly scared!

I've been discussing something vaguely similar with Tervamaki as a jump gyroplane development, and we agreed it was more like pulling oneself up by the boot straps...
But your idea is very interesting, as usual.
 

Himat

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I have been thinking about vtol concepts out of the box since they would have their place in aviation, a gap currently unfilled.

...
A rehearsal of the Avro Canada project Y with ducted fans along the rim instead of on central fan?
Or maybe just poded props along the upper rim?

ProjectY-Flying-NoseOnA.jpg
 

Aircar

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The concept of blades extending out from a central body is quite old (patent search will disclose many ) -the Z fold used on the Stemme motor glider is one type of extension that has appeared -- pulling the blades in for cruise like a tortoise pulling in it's legs .

Your description though brought back a memory of a quite intriguing model VTOL I saw at an inventor's fair about 15 years ago --the man who designed and built it was a dentist or chiropractor and had no previous aeronautical know how which probably helped . The configuration was like a frisbee being a hollow mushroom type with three support legs and an electric motor and prop 'lifting' DOWNWARDS mounted in the centre . The centre part of the 'frisbee' had a slightly elevated cap with a circumferential slot and the propwash going UPWARDS both impinged on the underside of the frisbee and also blew through the gap and exitted radially over the outside surface --the **** thing hovered and moved around under precise RC control just using little flaps on the periphery of the disc . The prop was of course pulling DOWN but it must have been that the momentum reaction from the expanding flow underneath and the entrained flow outside exceeded the downforce --it certainly worked very well and seemed to defy the 'lifting by the bootstraps' way of thinking . There was a company called Split cycle engine that set up in Queensland and he appeared on their website some years ago in some sort of technology park set up --his first name was Terry but I cannot remember any more other than the basics of the VTOL model . I think that the Split Cycle engine company folded up (after suckering Sir Jack Brabham to spruik for them ) owing a lot of money and he might have returned to Darwin. The model was very impressive though.
 

autoreply

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At least one UAV @ TUD was designed and they predicted spectacular results.

Nevertheless, why not switch to something more conventional? Something like the OV10 Bronco for example with 2 big props (or many smaller, blowing at the nose) and slotted flaps might be capable of VTOL with the nose jacked up 45 degrees or so.
 

Aircar

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The split cycle engine was mentioned @ Split cycle engine - Wikipedia, the free encyclopedia --the VTOL model used a multiblade propeller called "jetfan' which was used for the engine's cooling fan as well and is also mentioned in the Gold coast company directory of the firm .

The "Mach 20 Flying saucer" thread concerns German chemist Peter Plichta's design of a VTOL disc aircraft using contra rotating peripheral fan blades and fairs them over with sliding covers for cruise --maybe an easier method than trying to retract the blades (and end plating the blades themselves to reduce tip losses --recirculation could be a problem ,the 'vortex ring state' in descent .
 

karoliina.t.salminen

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autoreply:

This is just speculation about an idea, not necessarily (necessarily, never say never) any concrete actual implementation goal, but:

- The VSTOL with slotted flaps and tractor props that would blow the wing would be good as an airplane and I have been considering that. It would have similar use case than today's STOL planes do.

- However, it still would require airport or airfield, even a small one, or at least open space of some sort (like bushplanes that land on river bend). It is still an airplane, and not as flexible as helicopter. Vertical landing and takeoff is a completely different thing. Land to your frontyard.

This kind of helicopter-like versatility could be useful in UAV-applications as well (today's camera copters are rather small, to replace all cinema-cranes, the copter would need to be able to carry stereo-RED-Epic -system with a pair of heavy Cine-lenses with gimball and gyro stabilization). That would be fun to implement to show to the World that autonomous flying robots shooting the movies is the way of the future. DP would just select with iPad the tracks that where the cameras would move. That could be even cheaper than a large staff operating cranes etc. manually.

Aircar:

- I think the problem with any combustion engine is the response time it has for throttle input.
Computer controlled stabilization requires the latency of the props to be very low, otherwise the stabilization will be extremely difficult. Electric motor can be throttled up and down very quickly. Of course in the idea I wrote to the blog about blades sticking out of the body, the stabilization would have to be done by turning the blade rather than controlling the speed. But if it was a ring shaped multicopter with central body instead, each prop could be throttled up or down algorithmically similarly than the stabilization happens on today's (RC scale) quadrocopters.
 
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