Backpack Gyro

[Bruno]

How about giving the pilot some off-road rollerblades (yes, they exist), and turn his/her legs into the landing gear? He or she would still have to be a daredevil/suicidal to try it, but I know I'd consider it...

Pilot's legs are a much better landing gear than wheels for rough terrain -- provided he flares properly. A good flare meand landing within 2-3 steps. The support legs help here, exerting drag. If the pilot has to run on landing, he has botched it. Landing a powered hang glider is generally considered easier than landing an ordinary hang-glider.

 

[Bruno]

Two illustrative clips of foot-launched powered hang-glider take off.

You can see the 'trailer' with the engine and the prop clearly, and the way it is supported by skid legs (which retract in flight).

http://www.youtube.com/watch?v=uiFkJf6IKLg
http://www.youtube.com/watch?v=r03g2ZDs0lY&NR=1

 

[gyroguy]

The backpack gyro is an interesting concept. It may even be possible.

A few years ago, a Japanese company brought out a backpack helicopter, the GEN H-4. It had contra-rotating rotorblades for torque cancellation and four (4) two-stroke engines. Total horsepower, as I recollect, was 40 horsepower. I have photos of it being demonstrated, in hover mode, at Oshkosh. It was not truly "backpack" as it had a tripod with a small seat, and the engines/reduction drive/rotorblade unit above the pilot's head. The demo pilot had learned to fly it w/o helicopter flight instruction in a very short period of time. It was light enough to qualify as an ultralight, as I remember. It was an impressive engineering achievement.

In the early 80s, when what we call "ultralights" today were called powered hang gliders, there was an FAA requirement to demonstrate foot-launching capability. I've done this... with a good headwind... and less good sense than I would have admitted at the time. The takeoffs and landings were stressful but possible. What is possible for a fixed-wing powered hang glider might also be possible for a gyroplane.

FYI, there are currently foot-launched powered parachutes that I've seen fly. The ones I saw had cute little backpack 20-horse engines.

So far we have back-pack and/or foot-launched fixed-wing hang gliders, helicopters, and powered parachutes. Why NOT gyros? Instead of making the assumption that a backpack, foot-launched gyro is impossible, let's consider what would have to be done to make this a reality.

It's easy to tear down the idea, but much harder to look at it and say that maybe this idea could be made to work. Even if you would not want to pilot a backpack gyro with foot-launch capability, are there things we could learn from the exercise of designing one that might have a chance to work?

 

[Bruno]

In the early 80s, when what we call "ultralights" today were called powered hang gliders, there was an FAA requirement to demonstrate foot-launching capability. I've done this... with a good headwind... and less good sense than I would have admitted at the time. The takeoffs and landings were stressful but possible.

The modern foot-launched powered hang-glider is a much more practical machine. The British Doodlebug, in which you sit in supine position, rather than lying prone, is even a fairly practical fly-and-camp proposition if your camping is totally basic. It has a (very small) baggage space.

Instead of making the assumption that a backpack, foot-launched gyro is impossible, let's consider what would have to be done to make this a reality.

It's easy to tear down the idea, but much harder to look at it and say that maybe this idea could be made to work. Even if you would not want to pilot a backpack gyro with foot-launch capability, are there things we could learn from the exercise of designing one that might have a chance to work?

Agreed. Nothing practical may come out of the exercise in the end, but we'll be a bit wiser.

 

[Ralph]

If you have ever seen the mast of a conventional gyro that has experienced a major rotor strike or high-speed flap, you would see the problem. The amount of energy stored in a set of spinning gyro blades is awesome. If it would bend a mast, your back would be broken like a rotten stick. I am very high on light-weight gyros, but something other than your body has to absorb all that energy when something goes wrong.

Ralph

 

[Bruno]

If you have ever seen the mast of a conventional gyro that has experienced a major rotor strike or high-speed flap, you would see the problem. The amount of energy stored in a set of spinning gyro blades is awesome. If it would bend a mast, your back would be broken like a rotten stick. I am very high on light-weight gyros, but something other than your body has to absorb all that energy when something goes wrong.

Ralph

Please note the setup I am proposing as food for thought -- that of the foot-launched powered hang glider. The wing has no fixed, solid connection to the pilot.

What the pilot is directly connected to is a harness containing the engine and the prop. The pilot and the harness hang suspended by special belts from the apex of the control triangle.

The forces you are talking about would not be transferred directly to the pilot's body.

Imagine the hang glider control triangle as playing the role of the gyro mast, with the rotor head at the apex instead of the wing and you get the rough idea.

 

[Sita]

The pictures shown by SamL are from the Danish engineer Vincent Seremet.
For Bob Simmon's info,Mr. Seremet never applied for a patent and he did test fly them.

The first two pictures are from a rocket (!!) powered version and the last picture was test flown towed by a car.

It probably all boils down to what one expect from a back-pack gyro.
If you like to fly with 60 mph for a couple of hours than the back-pack gyro is probably not a good idea.
If it's used for slow flying for short duration,I don't see why it would not be possible.
Most people seem to think that a 20 ft+ rotor is needed for ANY gyro.
The WW II Haffner Rotachute,from which Bensen took his idea for his line of gyrocopters,was succesfuly flying on a lot less than a 20 ft rotor.
There is a video of one of the Russian members showing a back-pack gyroglider towed behind a car flying just fine.

 

[Rotor Rooter]

Here is another backpack helicopter, which might not have been mentioned.

 

[Jens]

Here is another backpack helicopter....[/IMG]

It is not a backpack helicopter.... it's a sidepack helicopter

But it looks quite good.

 

[Bruno]

It is not a backpack helicopter.... it's a sidepack helicopter

But it looks quite good.

Looks like an inverted outboard boat engine. Maybe that's how a backpack helicopter assembly should look...

 

[Jens]

Looks like an inverted outboard boat engine. Maybe that's how a backpack helicopter assembly should look...

You might be quite right.

A single fixed rotor is uncontrolable - almost.
We need counter rotating rotors.

2 x 20hp aircooled outboard engines might be a way to go.
But 20hp aircooled outboard engines... does they excist?

With 1 engine on each side we get the COG correct - right under center of rotor - and then ad a simple 3 legs landing gear..... :first:

 

[Rotor Rooter]

Jens,

Two engines might provide a level of safety, due to redundancy.
~ alternatively ~
perhaps the disk loading would be too great for one engine and the craft might enter and remain in a vortex ring state.
:noidea:


Dave

 

[karlbamforth]

And if one engine stops it doubles up as a pilot blender, cool, 2 uses in one.

 

[Jens]

Safest rotor craft?

Safest rotor craft?

And if one engine stops it doubles up as a pilot blender, cool, 2 uses in one.

Make no sense to me.

There are already build workable rotor crafts of this type with 1 as well as 4 engines.
If used as Franz Schoefman does, it is the most safe rotor craft in the world - I think.

 

[brett s]

Any rotorcraft that uses your legs as landing gear & has spinning blades right over your head has a long ways to go before being labeled as the "most safe rotor craft in the world".

One slip on uneven ground or wet grass can mean death depending on how lucky you are.

Or for that matter, even a power loss if you drop enough to collapse your legs & tip over - which might not be very far with the weight of it on your back.

 

[Jens]

Agree

Agree

I totally agree, brett.
But I have NEVER labelled that type of rotor craft the "most safe rotor craft in the world". Read last line in my post #51.

If you build from the following rules and use it that way, you can have the most safe rotor craft in the world - I think:

1. Coaxial is almost the only way to go.
2. COG of machine and COG of body has to be in line with rotor C/L.
3. A landing gear on machine combined with using ones legs.
4. Fly low and slow – as Franz Schoefman.
________________________________________________________

I know very well how much back machine it is funny to have on your back.
I have had hundreds of starts and landings with a ‘backpack machine’, and I just test flew my new machine this Sunday in Denmark.
Dry weight of my old homebuilt machine was 30 kg. The new kit build machine 24 kg, and with fuel 30 kg, and that’s enough.
I totally agree that twice the weight on your back and 2 spinning props/rotors on top is very dangerous and a HUGE design flop.

Here is a picture taken yesterday here in Norway, of my new machine and my not so new body :

(More pictures: http://www.flyvglider.dk/forum/forum_posts.asp?TID=256&PN=1&TPN=1 )

 

[Rotor Rooter]

Jens, nice pictures.


I wonder what the weight and safety situation might be if the back-pack consisted of a couple of side-by-side rotors (large light propellers) c/w electric motors?

The 'rotors' could be guarded and the battery-pack might be hanging from the back-pack, so that it landed first and behind the pilot.


Dave

 

[Jens]

Dave,

Only the Franz Schoefman and the Gen-4 are realy working!
So stay very close to their design - I suggest.

Schoefman with 28 hp, is doing it MUCH better than the Solo Trek with 100 hp - from what I know and have seen.

 

[Rotor Rooter]

Jens, Your point are good ones.

However, the Solo Trek is not a good example of the side-by-side configuration.

Is is generally believed that the side-by-side has the greatest thrust to power ratio of all configurations. Of course, the additional structural members etc. will reduce this advantage.


The following drawing may be of interest.

Dave

 

[DrKev]

backpack gyro

backpack gyro

Don't know if this thread is vstill active, but found this on youtube.

Backpack gyro in action:

‪Exlusive Demo‬‏ - YouTube