Ground Flying Gyro

[Jens]

Ground Flying Gyro?

By GFG I mean:

"A gyrocopter with performances best comparable with a paramotor - except the Ground Flying Gyro only fly on ground effect at 25-40 km/h, 15-25 mph."
_______________________________________________

I have very litle practical experience with the gyros, (only been passenger once, and have made a bensen rotorhead) so your opionen are welcome in order to determine wether this category or concept should have any future for me or others.
_____________________________________________

I admit much inspiration come from the paramotor:

_____________________________________________

I have:

1 body. 56 years of age and 85 kg - 190 pounds.

2 rotorheads
1 paramotor. 15 hp (will be changed to 20 hp) 25kg - 50 pounds, thrust now 50-60 kg - 110-130 pounds

1 bensen frame


The complete paramotor - except harnes - should be attached to the gyro.
And easily deattached and used with the paraglider
____________________________________________

I only need:

Something to put on top!
(Don't tell me I should just use the paraglider )

I want a ROTOR!

A rotor that is simpel, cheap, can be homemade, fly slow, simple rotorhead and give good lift in ground effect.
___________________________________________

I think of:

4 blade rotor.
Dia. 5.5 m - 18 ft. (or less?)
"Hubbar" 500 mm - 20 inch.
Blade of wood (or plastic?) 2500x250x25 mm - 100x10x1 inch
Angel(s) ?
Rotorhead?
No tetering?
Coned up with wire? (2 blades only?)

Or counter rotating rotors? Advantages & disadvantages?
____________________________________________

I hope you have some comments, and I would like very much to here them:

1. Will it fly?
2. How is flying in ground effect? Turn left and right 360 dg.? ?
3. What kind of rotor for a Ground Flying Gyro?

 

[Ga6riel]

sorta takes the mind back to the old rogolo wing

 

[scottessex]

????????????????????

 

[PRuffin]

Scott, I think (maybe) he is asking if he can put a 20 hp motor on a gyro frame with an 18ft 4 blade rotor system and be able to fly in ground effect.

 

[chuter]

only fly on ground effect at 25-40 km/h, 15-25 mph."

Why would you want to do that?

If you've got a paramotor, why not really go flying?

Some would say skimming along the ground is more dangerous; more opportunity to touch down at the wrong angle and tip/tumble over.

in order to determine wether this category or concept should have any future for me or others.

Not for me, thanks.

 

[PRuffin]

Ditto, what Chuter said.

 

[scottessex]

I guess a hovercraft would be the closest thing, and probably alot safer and cheaper too.

 

[Jens]

Sorry.

Sorry.

Scott, I think (maybe) he is asking if he can put a 20 hp motor on a gyro frame with an 18ft 4 blade rotor system and be able to fly in ground effect.

Yes, that's the way I maybe should have put it
_____________________________________________

Never the less, I think I know too litle about ground effect.
I don't know at what height you are "in ground effect", and how many hp's you save by that.

My idea is or was: saved 3 hp in 10 feet above ground(from wheels).

If these figures are much less, my talk about flying at ground make no sense

In that case - sorry, if I have spread some confusion here.
_____________________________________________

Anyway - in or out of ground effect - the only thing I need in order to be into rotorcraft flying is a ROTOR.
Or rather: Can a rotor be designed that will do the job, and preferably fly very slow and be rather easy to homebuild?

 

[PW_Plack]

Jens,

You cannot fly a rotor without somehow accommodating teetering, unless you limit the machine to zero airspeed. As the blades rotate, at any moment the blade moving forward relative to the machine's direction will create more left than the blade moving backward, or retreating. Teetering allows the blades to change angle-of-attack to compensate. Without it, you'd simply roll toward the side of the retreating blade.

A two-blade rotor allows the use of a simple teetering joint at the hub, since the advancing blade's move up is coordinated with the retreating blade's need to move down, and their tip speeds always match. In any rotor with more than two blades, the rotorhead becomes much more complicated. The head must provide individual hinges for each blade in both the teetering and fore-aft directions.

As for ground effect, that is normally observed at an altitude above ground which is approximately equal to the rotor diameter (or equal to the wingspan, on a fixed-wing.) I'm afraid these guys are right...a machine flying in ground effect would be in a dangerous situation in all phases of its operation, and not very practical. It would need lots of smooth ground near its hangar, and could not be used for cross-country travel, except perhaps over roads or water.

 

[birdy]

Paul, i think he's thinkn of a 4bl setup with indervidual hinges.[ Coned up with wire?]

Jens, i dout a 20, or 40 hp motor is even going to get your gadget off the ground, not enough power to override the rotor drag.
It may hop, but it wont fly.

 

[mceagle]

I think he is asking if he can put a 20 hp motor on a gyro frame with an 18ft 4 blade rotor system and be able to fly in ground effect.

A common misunderstanding here. Going shorter and adding extra blades does not necessarily improve efficiency, especially in a small diameter.
If you wish to fly with minimum horsepower, you need longer blades, not shorter and only two blades for efficiency. It would be hard to home manufacture the blades to the required efficiency level without considerable airfoil and autorotational knowledge.
It is no fun and takes considerable expertise and experience to fly a marginal gyroplane.

 

[Jens]

Low performing gyro's.

Low performing gyro's.

sorta takes the mind back to the old rogolo wing

Well - I think it is a good idea to revive or strengten the spirit from that time,
and revive the category of low performing (homebuild) gyro's.

It is an additional category to what we have today -not a substitute.

Maybe development of even lower performing gyro's is possible

In Denmark the weight limit for an UL-gyro is 180 kg - 265 pds.
That can mean - almost - that a gyro with 100 hp and 100 mph is called an Ultra Light Gyroplane!

After that, it is hard to find words for a category of 20 hp and 20 mph.

 

[Jens]

Low speed and height....

Low speed and height....

!!

Jens,

You cannot fly a rotor without somehow accommodating teetering, unless you limit the machine to zero airspeed.
Jens: I understand.
That was one of the reasons I thought of 4 blades and app. 3 ft. shorter, and then cone them up with a wire.
This coning should help, but of course limited - thats why we have the teetering system - right.
I thought this coning might be good enough for 20-25 mph?

Remember I accept, even prefer, lower speed, which again mean I accept weather conditions as for the paramotor - almost 0 wind.
Does this help my idea?

As for ground effect, that is normally observed at an altitude above ground which is approximately equal to the rotor diameter (or equal to the wingspan, on a fixed-wing.) I'm afraid these guys are right...a machine flying in ground effect would be in a dangerous situation in all phases of its operation, and not very practical. It would need lots of smooth ground near its hangar, and could not be used for cross-country travel, except perhaps over roads or water.
Jens: Thanks, that is clear and usefull talk about ground effect.
I fully agree about the flying - but compared to NO rotor flying, this is great, if it just would do that
And maybe with a bit smaller dia. on rotor, the speed and height I wish, and 0 wind it might not be that dangerous?
My guess - therefore this debate.

I know I am asking quite a few quistions - and I could get some answers by reading books about this - but I enjoy learning and communicating with live people.

 

[Jens]

A super floater....

A super floater....

Thanks for your answer.

After first reading, I thought: "Jens, forget this project - if it can be done, somebody would have done it long time ago !"
But I still have some hope left:

A common misunderstanding here. Going shorter and adding extra blades does not necessarily improve efficiency, especially in a small diameter.
If you wish to fly with minimum horsepower, you need longer blades, not shorter and only two blades for efficiency.
Jens: Yes, but IS it efficiency I am asking for?
I have low horse power, but I want "to pay for" the lacking hp's with less speed and weight, stay in ground effect, weather conditions as for paramotors and a flat flying area.
This are different conditions than usual - to say the least - I think?
But have I "payed" enough - because that's my original idear that this is enough?

It would be hard to home manufacture the blades to the required efficiency level without considerable airfoil and autorotational knowledge.
Jens: Yes, so far I have considered that home manufacturing of rotorblades are too much.
The major reason I came up with 4 blades is, that I only would have 1/2 load on each blade and include about 3 feet shorter it now might be a home manufacturing job?


It is no fun and takes considerable expertise and experience to fly a marginal gyroplane.
Jens: Such a super floater or rather extreme floater I am asking for - maybe no one have been flying that before so it can be hard to tell - but sure it would be hard to fly - as it is hard to drive a 50 or 100 years old car.
If you compare it to NO rotor flying at all - it might be a lot of fun - only doing it would really tell, but I like to have a high possibility for succes before going ahead.

 

[Bob]

Geez Jens... sounds like one of my Posts ! hehehehehhe
the idea Sounds good at first, but when you realise the craft will self distruct at 20mph as easily as it would at 50mph you have to atart thinking over again... Smaller and Lighter is a Fantastic idea.... but not at the loss of safty ... staying in ground effect is what I have been doing for 3 years.... I can't seam to get out of it (heheheh) its DANGEROUS in ground effect!
its like Hypnotizeing a Cobra... it can be done but its risky as hell !
Go small if you want ! that is a great idea but Plan on leaving ground effect , being close to the ground is dangerous in an aircraft.... I believe you could get your gyro and glider power pack off the ground well enough useing a conventional rotor ,(tetering head is a must)and conserve weight as much as possable
...you will have a piece of flying lawn furniture when done... flemzy but very light ! ... but you will have to use a larger rotor... probly 28 to 30 ftin diam....
now weather or not your 20hp motor can push that rotor is unknown to me ... once the wheels leave the ground the craft should speed up enough to leave ground effect in any case.
Granted a 20hp motor can put out a hudge amount of thrust, it is very impressive indeed ... but a 30 ft rotor puts out alot of drag as well... I do not know the answer !
... Do not try rotors without a tetering head !... make a modle
and throw it a bunch of times and you will see a rotor will turn on its side when moveing foward ! adding a dehidril to the blades
will help but it does not cure the problem. one gust of wind and over she goes... the tennancy is still there .
thats why the tetering rotor head is so unique ! its a simple easy cure to the age old problem of a spinning rotor.
...when in doubt I say build it STRONG! not lighter and weaker!
I'ed rather tumble down the runway in a strong gyro than one that is a weak flemzy thing ...but the choice is yours...
these things react so extreamily fast that it will take a few crashes to get the haing of it.... what a way to design a craft eh ? but thats the truth !
thats why they all scream INSTRUCTIONS ! it is a very good idea !
haing in there
good idea there .... make it work !
Bob.......

 

[Jens]

Extreme floater rotor.

Extreme floater rotor.

I am not sure anymore, that I should have started this thread

Efficiency for a rotor must be very comparable with the propeller or a fan.
That you move the rotor after spinning is something else

So best efficiency = Few blades, big diameter.

More blades can give same pressure/thrust/lift on a smaller dia./area, but is a (bit?) less efficient.

THIS IS VERY MUCH DONE - and if you don't go to extremes in this, your loss in efficiency don't go out the buttom.

In order to get somewhere you move the rotor and (soon?) tetering becomes needed.
As it is mechaniclly complicated to teter many blades you alway (almost) see only 2 rotor blades on a gyro.

I want 4 blade because of:
1. less dia. - more safe in ground effekt.
2. 1/2 load on each blade
3. 1. and 2. together make them a lot easier to homebuild.


1 or 2 options maybe?

1.No tetering. High up coning with a wire.
Speed less than 25 mph.

2. With tetering and a rotor like this:


Make the angle 1/2 of what you see on the picture and 5 inch apart.

 

[Jens]

Stay in ground effect...

Stay in ground effect...

Hi Bob,

What do you mean:
"staying in ground effect is what I have been doing for 3 years...." ?

Geez Jens... sounds like one of my Posts ! hehehehehhe
the idea Sounds good at first, but when you realise the craft will self distruct at 20mph as easily as it would at 50mph you have to atart thinking over again... Smaller and Lighter is a Fantastic idea.... but not at the loss of safty ... staying in ground effect is what I have been doing for 3 years.... I can't seam to get out of it (heheheh) its DANGEROUS in ground effect!
.........................
.................

haing in there
good idea there .... make it work !
Bob.......

You might be right, that it is TOO dangerous to stay in ground effect - I have no practical or hands on with gyro's - but that's one of the things I could get out of this project
- if not all of you "are shooting it down"

I expected it hard for most of you, and imporsible for some,
to understand the low requirements I set for this category - and be happy with it!

What is this category all about:

1. Design an extreme floater rotor - max dia. 20 ft.
Speed 25-40 km/h, 15-25 mph. App. 25 kg/55 lb. ?
2. Stay in ground effect.
3. Use an old Bensen frame or similar. 25 kg/55 lb.?
4. Use a complete paramotor 20-30 hp's, or a gocart engine 20-30 hp, or any other small engine less than 40 hp. Weight app. 20-30 kg./44-66 lb.
5. Total weight machine app. 75 kg/165 lb + body = 160 kg/350 lb.
6. Home made project.

Flying conditions:
A. Easy air and almost 0 wind.
B. Flat flying area.
C. Not advisable for everybody.

What you get:
- Hands ON experience with rotorcraft.
- Learn to fly it.
- LOT OF FUN !

This you do in a short periode after the finishing of it - after that you only, or mainly, talk about the good old day's when you where flying the
Ground Flying Gyro

If it ever will fly

 

[Ga6riel]

machines designed and intended to fly in ground effect are really quite safe, for the mostpart they will operate anywhere a hovercraft can go and then some, and without the hassle of skirt wear.

The little ESKA 1, of 992 lbs flew on a mere 30hp, with a power loading of 33lbs per HP. Maximum altitude was 90 metres, and about 3 metres IGE.

There is little saving in flying in ground effect unless you can make use of the significantly different power to weight loading,
Edit: the usual route is to extend range, for while cruising IGE the fuel burn is considerably less, range can therefore be increased perhaps 200%. To consume more power equals more height, untill you reach the point were you begin to ascend out of ground effect. This is analogous to how a gyro operates all the time, and thats a plus. Another plus, and you heard it here first, the AC typicaly moves aft for an aircraft IGE, for reasons more obscure than are imediately apparent, this does not happen on a gyro, or at least to anything near the same extent, and thats a BIG plus. For the geometry of a FW AC in this situation requires much manipulation and burning of midnight oil, and even then stability is marginal. The most successful types are reversed delta wings with considerable anhedral, coupled with 'S' curved wing sections that are designed to suck the aft part of the mainplane down. Beyond that, a huge tail usually exceeding 30 odd % of the mainplane are required to maintain an AoA of around 6 degrees ~
having said that, you need to take off first.

pictured Ekranolyetny Spasatyelny Kater Amphibya (ESKA -1) Janes 1980

 

[Jens]

Hi Rob,

Excellent - a much better way to tell what I want.
Can we design a rotor for that?

 

[Ga6riel]

As this would be groundbreaking design (I hope not litteraly) my personal inclination would be to change very little on a conventional gyro, hire the best godam test pilot you can get your hands on, and see what happens. Then make incremental changes appropriate to what has been learned. A strong crash survivable structure is mandatory, for protection of the pilot is vital to the cause.

To that end, I would require a fuselage with a straight keel on the bottom, a foam floor below the pilot, a nose that can handle an impact, a canopy that will keep limbs inside, and fires and debris outside, and a rollover structure for obvious reasons.

I would favour a tractor type with taildragger gear with trailing arm suspension.