My crazy STOL idea ...

[bexrbetter]

First watch these 2 videos, they are worth watching just for themselves ...

 

If you're bored easy, jump to 3.40 minutes when the action starts..

 

 

.

 

 

[bexrbetter]

Now some of you are saying gyrocopters, so?

 

Well yes and no, they are decent sized tractor gyroplanes actually, not small pusher gyrocopters that there are a number of around.

 

I have no idea why these were so popular back in those days but don't seem to have maintained a following, and that is a question btw. It's amazing when you see their capabilities and their safety margins. Who wouldn't want a plane you can take off and land in 100 meters?

 

I kind of figure that their 'wing'less' appearances don't do them any favour, and maybe a fear of needing to learn a new skillset.

 

So I had it in mind that my second model would definately be a STOL, so why not a hybrid of the craft I am building with a gyroplane. Retaining short wings, like the one in the first video where you can clearly see him operating the ailerons and HS, would enable 'normal' plane controls without regard to the rotor, i.e. and easy changeover for a rec fly pilot.

 

Then there's the no stall and no spin safety for newcomers.

 

Also with short wings that have real functionality, that will reduce the size of the rotor as well, so you would have (at a guess) lightweight 2.5 meter long wings that were easy to handle and storage after removal, and a shorter rotor (twin blade) under 6 meters (again guessing) that would sit longitudinal over the plane without removal making the craft easy to trailer and store at home.

 

Might look something like this ...

 

 

 

This is quite easy for me to do based on my current build, literally trimming the wings back to the Flaps, that would then become the Ailerons, and I already have a strong roll bar to base the rotor from.

 

But possibly the best reason of all, I want to hit the burgeoning Chinese rec fly market, guess what, they have no airfields, one reason helicopters are the main crafts displayed at shows here, with plenty of open pusher gyrocopters for the same reason, but not so many light planes because where do you fly them? - so a craft like this could be exactly what is needed.

 

Further reason, electric planes are very unlikely to ever happen in current configuration simply due to the weight. Using the full length wings and a rotor for the extra lift required might resolve this, and the rotor can be used as a regen charging medium to boost range when possible such as descent when the extra drag is a requirement. For those who don't know, the rotor is not powered, it spins freely.

 

So there you go, as soon as I finish the current plane, very likely I will do this, no negatives as far as I can see.

 

 

[geoffreywh]

There are a couple of Cierva type Gyroplanes in production (using a radial for originality).. Look great. But you have to to better than the video with regard to u/c design:laugh:

 

 

[Head in the clouds]

Good luck, but it's not a new idea. Carter Copter have been onto the hybrid plane/copter for more than fifteen years having spent several millions so far, and still haven't reached market yet. And theirs incorporates vertical take-off and landing without having a powered rotor, instead having a massive amount of stored energy in the rotor due to using depleted uranium weights in the rotor tips. Consequently the centrifugal loads on the blades and hub are immense, years ago someone quoted something like 300 tonnes a side ...

 

 

 

[Jaba-who]

Bex, The problem is your idea has been tried before ( ok in helicopters rather than autogyros) and not resulted in workable aircraft. So despite the seeming practicalness of it it doesn't seem to work. The nearest "big wing" area gyro I am aware of is the Cartercopter although it's a pusher type prop. But it seems to have gone quiet now for a few years.

 

There are a number of negative interactions that happen between the wings and the rotors ( at least in helicopters - not sure about autogyros) and as best I recall the effect induces lots of bad effects when the wings are much more than stubs. The wings cause Interference with air flows off the rotors.

 

Rotors can't maintain safe lift patterns at speeds above that at which receding blade stall starts so you have to include mechanisms to slow or stop the blades as the wings take over the lift as speed increases. Apparently that becomes increasingly complex - Sikorsky and others have spent billions trying to develop slow rotors or stopped rotors in various positions and seem to have given away the idea.

 

Despite protestations about safety I did some reasearch a few years back and when you look at the stats of hours flown to crashes and deaths in crashes and gyros are actually bad compared to helicopters and disasterously bad compared to fixed wings. Lots of things contributing to this. Low hours, amateur pilots, limited experience are big contributors but the other is that flying in autorotation actually has very narrow limits to the safe envelope. All the margins are contracted and risk of straying outside them is high especially in some parts of the flight.

 

Gyros were popular in 1930s because helicopters weren't invented ( essentially) then. Once they came along the benefits of the gyro disappeared.

 

 

[Marty_d]

Interesting idea.

 

You could theoretically use many of the same bits - not sure what W&B is for a gyro, guessing the CG is under the rotor shaft?

 

However given that all the loads in flight would be at the rotor hub, you'd need to think carefully about the engineering and placement of the uprights which hold the rotor hub. For instance I don't think it'd be a good idea having a main support ending at the top of the canopy as per your pic (I know it's just an initial concept.)

 

I guess what would scare me off is that you're going from standard light aircraft building, which you understand very well, to incorporating rotors and all their differences (which you may understand, but I certainly don't!) - eg the design and construction of the blades, the loads on them, the calculations of lift, design of the hub, pitch, etc etc etc - and then there's all the unknown unknowns.

 

But if you've got all that under control... then go for it!

 

 

[rotax618]

I believe that the ideal sport aircraft would be a Gyrocopter with a semi-powered rotor, and short wings.

 

Supplying a small amount of power to the rotor system should accomplish several things.

 

1. It would compensate for the induced drag of the rotor system, lowering the disc angle and reduce the overall drag, increasing efficiency, overcoming the 1:2, Thrust:AUW requirement in conventional gyroplanes.

 

2. It would reduce the tendency of the rotors to slow down dangerously in negative G situations, giving a greater safety margin.

 

3. Supply power for short takeoff and providing a much lower minimum speed (hover in light breezes).

 

4. Prevent the rotor from slowing down when some of the lift is shared by a conventional wing.

 

Obviously the torque would have to be compensated, I envisiond the thrust engine could be moved laterall, off centre by varying amounts (pusher engine). A tractor engine could be pivoted sideways to offset the thrust by varying amounts.

 

The problem has always been the mechanical complexity, but maybe a hybrid thrust engine and a direct drive electric motor on the rotor would work.

 

Anyway food for thought.

 

 

[Deskpilot]

I'm no expert but the one time I flew in a gyro I was mightily impressed. So smooth compared with fixed wing aircraft.

 

R618, I tend to agree with you. Time for you to start designing.

 

Jab-who, how did your research re safety, take into account the 1000's to 1 differences in the numbers flying in order to come up with what-ever figures were quoted. I doubt that it was an accurate result.

 

Bex, stick with your current plan and on completion, do the mods on a different plane. I see where you're coming from with respect to flying in China and the idea may very well take off.

 

 

[bexrbetter]

Bex, The problem is your idea has been tried before ( ok in helicopters rather than autogyros) and not resulted in workable aircraft.

The only craft i can find similar in history is actually the early Pincain models with stb wings to enable aileron control.

 

No other craft since is that same as I am aiming for, it is a standard 'plane' with a 1 dimensional rotor operation, all the rest have 2 or 3 dimensional and are of rotorcraft foundation, including the Pincains and Kellets etc.

 

I find craft like the Carter to be somewhat of an overly complicated joke, far removed from what I envision.

 

when you look at the stats of hours flown to crashes and deaths in crashes and gyros are actually bad compared to helicopters and disasterously bad compared to fixed wings.

You are referring to short coupled, usually one seat, pusher gyrocopters, and I will always have the problem of getting it clear to people that isn't what I am doing and distancing myself from them

 

The issues of "PIO" pilot induced oscillation that have been the main killer, and are well understood for those craft. Being small pushers is part of the problem.

 

I would indeed be interested in any tractor plane based gyro that has had problems, but I have seen nothing, and they are out there, Pitbull, Little Wing and others.

 

While those vehicles are controlled by the rotor attitude, the controls of my craft will be standard plane Ailerons, HS, Rudder etc, the intention being that any rec fly pilot just gets in and drives without any concerns other than possible rotor speed up by an electric motor, set and forget.

 

.

 

 

[bexrbetter]

There are a couple of Cierva type Gyroplanes in production (using a radial for originality)..

The Bulldog never flew to my knowledge.

 

The Pitbull had 8 registered in the USA, uses a Subaru EA81 engine, how can you watch this and not want one! I think it's very strange they didn't sell better.

 

 

But again, they are both Rotorcraft, not what I am aiming at.

 

.

 

 

[bexrbetter]

eg the design and construction of the blades, the loads on them, the calculations of lift, design of the hub, pitch, etc etc etc - and then there's all the unknown unknowns.

Not my area, I would bring in the appropriate people.

 

There's an American mob who are a main supplier to the industry and they offer help and all relative product up to 600kg craft.

 

I don't think it'd be a good idea having a main support ending at the top of the canopy as per your pic (I know it's just an initial concept.)

I would use only the best quality tech screws into the persplex.

 

I believe that the ideal sport aircraft would be a Gyrocopter with a semi-powered rotor, and short wings.

Well it ain't that, it's a plane with short wings that has a rotor for additional lift.

 

I

The problem has always been the mechanical complexity,

Yes, to be avoided. Again, not building a rotorcraft per say.

 

.Bex, stick with your current plan and on completion, do the mods on a different plane. I see where you're coming from with respect to flying in China and the idea may very well take off.

The fit to China is perfect, will proceed AFTER I finish the current one.

 

No reason to choose a "different plane", what I have is fine to pursue it.

 

Thanks for all the replies.

 

 

[bexrbetter]

Despite protestations about safety I did some reasearch a few years back and when you look at the stats of hours flown to crashes and deaths in crashes and gyros are actually bad

Some first hand info on that from the Little Wing developer here ...

 

 

 

[eightyknots]

This is becoming a very interesting thread!

 

 

[bexrbetter]

This is becoming a very interesting thread!

Just wait till the girls and the grog arrive!

 

 

[rtfm]

The Bulldog never flew to my knowledge.The Pitbull had 8 registered in the USA, uses a Subaru EA81 engine, how can you watch this and not want one! I think it's very strange they didn't sell better.

 

Hi,

I have long had an on-again-off-again love affair with the gyro. Paul Bruty was going to teach me to fly one in exchange for my building and maintaining his website. Then he had his crash, and the deal was off. But the flame still flickers. And the most attractive of ALL they gyros has (for me) always been the Pitbull. It is so elegant - far more so than The LittleWing.

 

Does anyone know if plans for the Pitbull are available?

 

With regards the wings: I spent over a year working on a winged gyro design of my own. The designs are somewhere on my computer, but I have no idea where. I love your proposal. Go for it.

 

Duncan

 

 

[rgmwa]

Well it ain't that, it's a plane with short wings that has a rotor for additional lift.

... or maybe it's a plane with a rotor that has short wings for additional lift? Only way to find out is to build one Bex, but finish the other one first. We all want to see how she goes.

 

rgmwa

 

 

[Deskpilot]

Bex, by a 'different aircraft' I meant a second one of your design, not a different design. Sorry to confuse you.

 

 

[Marty_d]

How about short wings with a smaller rotor on the end of each one? Then you could have them spinning in opposite directions so you wouldn't need to offset your engine.

 

 

[Deskpilot]

How about short wings with a smaller rotor on the end of each one? Then you could have them spinning in opposite directions so you wouldn't need to offset your engine.

I dread to think about the gyroscopic effects of that idea, Marty. I'm no expert as I've said before but I doubt it's feasible. I wouldn't like to sit between 2 egg beaters a few inches from my head.

 

Bex, am I right in thinking you are thinking in terms of a fixed rotor head with only a spin-up device at the mast-head, and all control to be via conventional surfaces?

 

A general question to all, how about an electric set-up with the rotor also providing charge for the batteries?

 

 

[rotax618]

It would be extremely dangerous to have anything connected to the rotor system which could cause rotor speed decay. Even with the large kinetic energy stored in the rotor, it can rapidly slow when when it is subjected to negative G situations, so much so that the rotor has been known to strike the tail and propellor.

 

Maintaining rotor speed is essential to autogyro safety. The Groen autogyro was reported to use depleated uranium in the rotor tips to ensure conservation of rotor speed for jump takeoff anf flare on landing.

 

 

[red750]

I've watched a few of the videos that pop up at the end of the ones loaded on this site depicting futuristic designs. There are certainly some weird, wacky and wonderful concepts, linked to names like BAE, Airbus, NASA, Lockheed-Martin,etc.

 

 

[bexrbetter]

Deskpilot, yes, you "get it".

 

This is the closest craft i have seen so far ..

 

 

Helicop-Air L.50 "Girhel" helicopter - development history, photos, technical data

 

http://www.secretprojects.co.uk/foru...?topic=12871.0

 

 

[bexrbetter]

Does anyone know if plans for the Pitbull are available?

Probably around the net, may even be a kit available, certainly no reason you couldn't get a set of Little Wing plans and build a Bulldog from that foundation. Likely they use the same rotor components from the largest American rotorwing supplier, Rotor Flight Dynamics, Inc. - Home of the Dominator!

 

You just missed this one, I am shocked how cheap it is .. Pitbull gyro - maybe contact him to see if it's gone or not.

 

How about short wings with a smaller rotor on the end of each one? Then you could have them spinning in opposite directions so you wouldn't need to offset your engine.

Yes I considered that, but also considered the results if one side failed. Great idea but I just don't have the engineering resources to tackle it, the safety margins are at another level.

 

Deskpilot, I have seen a rotor come off an Autogyro, and not surprisingly the blades went instantly up like a rocket, so your head is in no danger. The Autogyro was building up speed just about to launch, luckily it was still on the ground.

 

It would be extremely dangerous to have anything connected to the rotor system which could cause rotor speed decay. .

My craft would still have the wing area and control systems of a fast sport plane, without the rotor it would still land as such.

 

it can rapidly slow when when it is subjected to negative G situations, so much so that the rotor has been known to strike the tail and propellor..

I believe this is more applicable to the flying lawn chairs, and not to what I am proposing.

 

I've got to figure a new name for it to dis-associate them from me.

 

 

[bexrbetter]

Been looking further at stuff for this, a set of rotor blades is either side of USD $4000.

 

There's nothing special about them, I can extrude multiple sets myself and have a holiday in Oz for that!

 

I also worked this arvo (Sunday) on the XPB, got to get that out the way now, so it's helping enthusiasm there too!

 

 

[geoffreywh]

don't give up on the autogyro, i like the short wing concept. would that reduce the need for a large rotor swept area? round body and radial engine, it would look and sound lovely...