height limited sport helicopter

[slowrotor]

I am seriously looking at the idea of a sport helicopter that flies within 10 feet or so of the ground (or water) at all times.
The thought being that it might be relatively safe staying low and slow in an experimental design. Maybe after years of testing, the envelope could be expanded. A crude design would be appropriate while testing and would be more likely to be completed than a fully airworthy craft.
It would have the capability of a hovercraft, maybe better, and would be fun for exploring the coast and deserts etc.
Any thoughts?

[ShyTorque]

Why not just buy an R-22 and cut three feet off each rotor blade?

[Bitmonx]

At 10 feet? How fast do you want to fly? Would not give you lots of time to react to an engine failure, wouldn't it?
It will be interesting to see what kind of ideas people will come up with.

[bugdevheli]

Slowrotor. You are not alone with this line of thought. Many might argue as they have in the past with me. Whats the point in a machine that is limited to little more height than a high jumper can clear, how is the height limit enforced etc,etc. I have heard all the arguments! However, when one considers what most people do when they fly helicopters for fun is:-
1. Want to take off and land often preferably in front of friends
2. Hover as much as possible because its good fun
3. Fly very low and slow, again because its fun
4. Give it a rub over and stand back and admire
5 Be able to say truthfully in the pub. Fish? not me mate, fly!

What they rarely mention is the arm and leg it costs to hire the machine. The financial risks if they bend something . The frustration of weather and availability or not, as the case may be.

Numbers one to four are hard to achieve unless you own five hundred acres and have unlimited funds. SO YES!! Light, reliable, affordable, machine capable of autorotation from its permitted height limit. It has got to come eventually. Do as I am doing. Make one, prove it, badger the rule makers till they give in. Lets face it, who would have thought years ago that two people of the same sex could get married!!

[HillerBee]

Gyrocopter?

[Graviman]

I am seriously looking at the idea of a sport helicopter that flies within 10 feet or so of the ground (or water) at all times.

My only thought is how could you be sure it always stayed within it's height restriction, since it sounds like it would be capable of leaving ground effect. The real risk is guy gets bored and decides to fly away. As a trainer it would be incredibly cost effective though.

Then again if you want to avoid collective:
http://www.youtube.com/watch?v=sl1CssG_7bg

From site:
http://www.rotaryforum.com/forum/showthread.php?t=10808

Mart

[Dave_Jackson]

Any thoughts? A thoughtless thought.
http://www.skyaid.org/images/Image27.gif
http://www.unicopter.com/Chairshot.gif

OK, It's not that good.


Dave

[Graviman]

Actually Bug's ring rotor idea will out perform that Moller thing, and stands a much better chance of achieving the affordable rotorcraft dream...

Mart

[bugdevheli]

http://img.photobucket.com/albums/v28/eboki/not%20sophs%20stuff/wingletbugring.jpg

HEIGHT LIMITED SPORTS HELICOPTER

[Graviman]

Bug,

Have you had to derate the BMW motorbike engine, or was does it have the required durability at full throttle/rpm? How much of the R22 swashplate system do you think you can adapt for the ring rotor?

Just a thought, design it to have full helicopter capabilities but fit my previously discussed idea.

The reason would be twofold:
1.A low hours pilot will not be caught out by an actual engine failure, so insurance can be nice and inexpensive.
2.The height the machine can obtain controlable, to keep CAA/FAA happy.

This leaves you free to develope the machine, in the full knowledge that in the future you can market a full helicopter. In the interim folks like myself can accumulate lots of inexpensive hours really getting to grips with helicopter handling near the ground. Either way you win. :ok:

Mart

[ShyTorque]

But to keep the CAA happy, this so-called "height limited" flight envelope must allow the pilot to comply with the 500 ft rule. Perhaps it should be optimised to fly best at 501 feet? :p

[slowrotor]

Thanks for the replies.... a windstorm knocked out my power yesterday.

Shytorque- I want low power and no more noise than an car. A low level machine would have to be quiet.

Bitmonx- I am not sure about a safe top speed at 10 feet, maybe 20-25mph, like the powered parachutes. Anything faster than 4mph would beat a kayak. 15mph would beat most boats.

Bugdevheli- I am glad world still has people with whacky ideas like you. (and me).

Hillerbee- gyrocopter? No! Must hover.

Graviman- I would limit the height by choice I think. Just like I don't fly at night by personal choice. Another idea would be to adjust the machine to only fly in ground effect.
I don't have any details yet. Just had the idea that I might be able to build a crude craft, where the idea of designing a fully operational helo would be almost impossible for one person like me. The human powered aircraft were similar in that they were crude and stayed low and slow.
I am thinking the basic design would be:
1) Rotor about 28ft and 200rpm for quiet and slow reaction at low rpm.
2) small low cost engine 25hp
3) use available gears, belts etc. from auto or tractor or whatever.
4) cost about $5000 for parts.

Thanks for your input everybody
slowrotor

[ShyTorque]

Slowrotor, in UK it's not only an issue with noise. The CAA insist (so it's a legal requirement, no argument) that aircraft fly no closer than 500 feet to any person, or anywhere a person might be. Unfortunately, in UK your low level only machine would therefore not be allowed to operate in many areas.

[slowrotor]

Shytorque-
In the U.S. ultralight flight machines are called vehicles. Ultralights are not considered to be an "Aircraft" and the 500ft rule does not apply to ultralight vehicles.

Also, I have no idea how a hovercraft is regulated and what height a hovercraft would be an aircraft.

[Dave_Jackson]

low power and no more noise than an car.
10 feet, maybe 20-25mph
"height limited" flight envelopehttp://www.unicopter.com/Think.gif

Electric motor.
Gen-set on casters with strong 10' long electric cable to craft.
Contact with ground, via cable, removes craft from aircraft category. :confused:

[Graviman]

Now Dave, y'ain't gonna have us awl hoverin' on hoovers agin is ya? :}

Slowrotor, the rotor spec sounds not disimilar to R22 with diam 25.16' and Nr 530 rpm. Why not just use twin R22 rotors and run them at say 375 rpm? I just mean stacking them before we get a symmetrical discussion. That way you get away with using R22 powertrain, with engine of your choice. Top speed may go down slightly, but needs calculating properly.

In truth, i am not sure why you are not just designing a hovercraft. As Shytorque comments, such a "flying" machine could only be used in UK on say an airfield for training purposes. I don't think "pilot limited height" would wash well with certification either. As far as i know hovercraft are only regulated in that they cannot be used on public roads.
Mart

[handysnaks]

You don't want a helicopter mate, you want one of these
http://images.encarta.msn.com/xrefmedia/sharemed/targets/images/pho/t041/T041616A.jpg:p :p

[Dave_Jackson]

slowrotor,

You may find this of interest. Dick DeGraw's Synchrocopter (http://www.youtube.com/watch?v=Q6mDK9XhklE&mode=related&search=Gyrocopter%20gyro)

I think he had 2 - 300 hrs of flying time on it.


Dave

[slowrotor]

I did some research on a category of craft called WIG (wing in ground effect).
They fly at about 10 feet usually over water. They have limited use, but also have certain some advantages. Google search WIG for info.

I think a rotor in ground effect (RIG) would be a new category of aircraft that I propose here. I am not sure if a RIG has ever been built.
A RIG would have the ability to VTOL, rather than the long takeoff of a WIG.
So a RIG would have many uses for scientific exploration, rescue, crop dusting etc.

New category to work on !

slowrotor

[Graviman]

Dave, I'm always amazed how compact intermeshers look without that tail rotor.

Slowrotor, what you describe still sounds to me like a hovercraft. The big problem is going to be protecting the rotor, this leads to a ducted fan. By the time you are finished i think you just find a way to take the hovercraft concept and push down machine weight and "disk" loading. Since the machine will have greater versatility (no skirt etc) call it the versacraft. ;)

Mart

[Mac the Knife]

Now, I know you guys are always worried about flying into wires...:\

Aren't there a lot more wires this low?

Sorry if it's a dim question :sad:

Mac

[slowrotor]

Mart,
Yes, a low helo is similar to a hovercraft, but a hovercraft has no cyclic for control in situations like hovering on a slope. Most hovercraft can't pass over a ten foot ditch either.
I have a book you might like Mart, the author worked on the Lockheed Cheyenne. The book is: Radio Control Model Helicopter Handbook by Don Lodge. Out of print but available at amazon.com for under $4. The book has some info that applies to full scale helos, especially the Lockheed gyro.

Mac,
Wires are sometimes pretty high. Its a problem. That is why low should go with very slow.

Check this out for low and slow. http://www.personalblimp.com

[Dave_Jackson]

Mart,I'm always amazed how compact intermeshers look without that tail rotor. I suspect that the short tail-boom on intermeshing helicopters, and on Benson style gyrocopters, may have been an overreaction to the elimination of the tail-rotor. The newer K-max (http://avia.russian.ee/foto/kaman_max_1.jpg) and fixed-wing craft have long tail-booms.


___________________________

Low and slow. (http://images.google.ca/imgres?imgurl=http://avia.russian.ee/foto/bo-102_2.jpg&imgrefurl=http://avia.russian.ee/helicopters_eng/bo-102-r.html&h=273&w=372&sz=40&hl=en&start=2&tbnid=_nwBGogjgMf0gM:&tbnh=90&tbnw=122&prev=/images%3Fq%3D%2522Heli-trainer%2522%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN) :ok:


Dave

[bugdevheli]

The CAA permit to fly for HLSH could maybe read

1 The pilot may only fly over private property with the consent of
the owner or landlord

2 The machine must be fitted with a ground proximity device

3 The helicopter must be capable of executing a full down autorotation
from its permitted operating height either from stationary hover or at
its maximum permitted speed

4 The pilot will be responsible for his own safety, and will not hold the
CAA liable for any injuries howsoever caused

Graviman thanks for your kind offer i will pm you

bug

[slowrotor]

Bugdevheli,
You might not need a permit.
Wing in ground effect vehicles have three regulation classes:
class A) unable to fly above ground effect
class B) able to jump above ground effect briefly.
class C) able to fly above ground effect continuous.

Class A and B are not considered aircraft by most aviation authority.

[IFMU]

I suspect that the short tail-boom on intermeshing helicopters, and on Benson style gyrocopters, may have been an overreaction to the elimination of the tail-rotor. The newer K-max and fixed-wing craft have long tail-booms.
Dave

The short-tailed Kamans grew a lot of vertical surfaces. I think like 4 on the huskie. If you read Prouty there are problems with intermeshers & coaxes, with respect to yaw authority, especially in autorotation. So, if you need a rudder, better make it a good one.

-- IFMU

[IFMU]

There was a thread, posted perhaps on rotorheads, about a rocket powered propeller. Some creative nutjob had carved a pine propeller, drilled a hole from the root to the tip for rocket power, and had the rocket spin the prop. It may have been a peroxide rocket. Tremendous power to weight, but they kept catching on fire. He ground ran a couple of them. This guy goes on to speculate the uses for this propeller, and he had a link to a small weight-shift powered helicopter, using a 2-stroke engine, counter rotating fixed pitch props (I think). The helicopter was of German origin. It seemed to have enough power to get light, but the 'pilot' got it airbone for seconds at a time with mighty hops (his legs are the landing gear. They retracted, but appeared to have little speed benefit). Here's your ground effect helicopter. Anybody save the links, or know what I'm talking about?

-- IFMU

[Graviman]

Graviman thanks for your kind offer i will pm you


Bug, Standing by. All unclosed thread refs deleted.

BTW you might like to see if you can find Commanche hub details for your rotor ring idea. Nick commented on this forum that it used elastomeric bushes to retain the blades to the spars in a "bearingless" design. I gather that the spars were clamped between two plates, which might give some ideas for your construction. I have been unable to find more detailed info, but the AHS search is a start:

AHS search on "Comanche" (http://www.vtol.org/cgi-bin/dbsearch/ahsdbsearch?session=634831493&task=search&q=%0D%0Acomanche)

----

Slowrotor, you got me! I am indeed a great fan of the AH-64, and also the X2 since it promises to reintroduce many concepts that fell by the wayside after Lockheed stopped that project. Technology like that belongs in the public sector where it will be of most benefit. I'll look the book up, thanks.

Agreed about cyclic control and improved versatility. I would be interested how the machine layout looks, since this will decide it's success. Most of the "air-jeep" concepts are based on 4 teetering rotors. The ground transport machines we design are more versatile than most, so probably prove the limitations of wheeled transport. Still i'd rather have been a helicopter design/analysis/test engineer. :sad:

Mart