Floats on a gyro?

[rtfm]

Hi,
I've seen gyros fitted with floats mentioned on the Web from time to time. What's the story about floats? Can they be fitted to any gyro? I would have thought a RAF2000 (or similar) gyro might be top-heavy? The idea is intrieguing, since I live in Auckland, NZ, and there are a zillion bays, inlets, beaches and coves up and down the coast. I'd live to be able to drop in...

Duncan

[rehler]

I would have thought a RAF2000 (or similar) gyro might be top-heavy?

The RAF (and similar) gyros are actually "bottom heavy" - CG below the prop thrust line. Floats would make them even more bottom heavy and add drag down low. This would make them more unsafe as the prop will be trying to push the gyro over into a forward tumble if the rotor ever looses drag (zero G).

I think the reason there are few floats on gyro is: (1) additional cost (2) added drag - difficult for the engine to have enough thrust to make it fly (3) unsafe due to low weight and drag.

[KenSandyEggo]

Actually, I heard that floats are extremely useful on a gyro. They mark the spot where you're hanging upside down in the water. :rolleyes:

Actually, prerotating becomes a problem also, I believe.

[barnstorm2]

Duncan,

I would LOVE to have floats on a gyro. The problems I have heard reported are just as stated here:

1. Lowers the thustline

2. Pre-Rotation.

I wish one of these experienced gyro designers around here would get a bug to design and build one for me ( to buy cheap ) :D


It seems to me ( only 2 years experience with gyros ) that the problem could be solved/lessened with:

1. Dropping a temporary Keel that would reduce the problem of spinning around during pre-rotation.

2. Using modern composite floats ( lightweight, low profile ) and a centerline thust design ( or lower than centerline thust, so with floats becomes CLT ).


There is an abandoned barge near where I boat on the Ohio River. The thought crossed my mind.... Hey what If I cover it with a wood deck and make the worlds' first gyro aircraft carrier!! :eek:

[rtfm]

G'day barnstorm2,
Mmmm... If these are the only major objections, at least one of them is a non-issue: that of the torque-related problems of prerotation. The only reason for prerotation is to shorten the takeoff roll. But if you're trying to take off from a river, your runway is MILES long... who needs prerotation at all? Just crank up the prop, sit back and taxi across the water into the distance until you reach sufficient RRPM. What's the problem?

The second problem - that of lowering the CG - is not quite so easily disposed of, but it, too, doesn't seem to me to be insurmountable. While floats may lower the CG, this is not necessarily as big a problem as it might first appear. Carbon fibre floats could be built weighing next to nothing.

I'm not an expert, and my ideas are those of the inexperienced, but the problems just don't seem that big...

Regards,
Duncan

[rtfm]

There is an abandoned barge near where I boat on the Ohio River. The thought crossed my mind.... Hey what If I cover it with a wood deck and make the worlds' first gyro aircraft carrier!! :eek:
Go for it, buddy! :D

[Doug Riley]

At the time I first started flying gyros, a friend of mine got his machine going on floats. I had planned to do the same. He had a serious crash into Long Island Sound, however. He survived with a punctured lung and other injuries. He told me that the machine dove into the water without command from him, and that back stick did no good. I stuck to wheels for the gyro and later bought a boat for watery adventures.

Floats present two different flight stability problems. First, they lower the CG appreciably, as has been noted. Second, they lower the aerodynamic center of the fuselage (to over-simplify a little, they add a lot of drag down low; at high speeds, this drag tends to pull the nose down; the end result is the same as engine thrust PUSHING the nose down).

I would imagine (though I haven't tried it) that prerotation torque would be manageable, at least up to modest rotor RPM. The air rudder would help, as would some strakes, keel and water rudder area on the floats.

The nose-over effects of low CG and low aerodynamic center are tougher to solve. There's only so high you can raise the seat before the either the gyro is unduly top-heavy or the rotor blades give the pilot a haircut.

The easiest answer is more HS power. It's difficult to build large amounts of HS power into a pusher gyro; there's a limited amount of room back there. It would be easier to fit a tractor gyro on floats. Cierva gyros were flown on floats, for example. Interestingly, even one of these (float-equipped tractor gyros with large HS) flipped forward and inverted on one famous occasion. The Cierva design was such that the machine recovered from the inverted position more or less on its own and the pilot was unhurt (although shaken).

A modern gyro probably wouldn't come out so well.

[Harry_S.]

Many years ago, one of our chapter members built a float equiped glider. At that time we had a land glider that we put hundreds and hundreds of hours on. The gliders were towed by car(truck) and by water boat. I was the test pilot for both.

There was a mite bit difference between flying the two models. No diff. in pre-rotation. Bear in mind , these were gliders, not powered gyros. My only complaint between the two models was getting *wet.* You definately will get wet. Not good on a cool day.

In addition, that water spray will hit everything; engine, prop, rotors. Damage and corrosion.

[gyroplanes]

The early issue of PRA's Popular Rotorcraft Flying magazine seemed to feature more gyros on floats than on wheels.
I sold an Air Command to a guy in Wisconsin who mounted it atop a Hobie Cat ! I heard it flew.
Here is a picture of a fellow club member who thought the water would be a softer place to learn to fly.
He was successful towing the gyro until he took up the offer of a tow from a faster boat. The new boat driver was enjoying the flying gyro so much he almost ran aground, leaving the gyro aloft without thrust for a while. When the thrust resumed it was over 90 degrees away and pulled him sideways and down. Splash, the gyro was rebuilt with wheels.

[gyroplanes]

Another shot

[gyroplanes]

Another shot

[gyroplanes]

Here is the last one.
Brings to mind a quote from Ken Brock.
I once asked Ken if he ever tried float flying. His reply was "In California we hardly have enough water to drink, let alone fly off of"

[Curran3]

I've got an old set of floats that came off an Avid Flyer sitting in my hangar that I'd been trying to figure out what to do with. They're foam with fiberglass skins. They're not very heavy. Even with the mounts and rudders two of us old guys pick them up and flip them over without working up a sweat. If any of you guys gets crazy enough to try and make a gyro safe on floats I'd be happy to swap them for something or other.
Curran In Jacksonville, FL

[Harry_S.]

Those pictures bring back memories, Tom.!!

[PW_Plack]

Jim Vanek's video has footage of one of his dad's old Vancraft models taking off and landing on floats. It appears to have been flown very carefully and slowly, and from Jim's comments I gathered that the aerodynamic issues were a bigger problem than the CG-related ones. If these problems could be solved, gyros should offer some significant advantages over fixed-wing seaplanes.

I've been for only one ride in a seaplane, a Cessna 182 on floats. By the time we reached takeoff speed, I was amazed that the airframe was still holding together. Seaplane pilots actually prefer a light chop for takeoff, but man...what a pounding! A gyro that could take off at 15 knots would be worth considering.

What about floats on semi-retractable arms, so they could be raised to a point near the vertical CG after takeoff, then dropped back down for landing? Could be heavy and a little complicated, but would solve both the aerodynamic and CG problems.

[Hognose]

I think the reason there are few floats on gyro is: (1) additional cost (2) added drag - difficult for the engine to have enough thrust to make it fly (3) unsafe due to low weight and drag.

Makes sense. Now, you could design it so that the floats were structural. They could actually replace the keel, serving kind of like the booms on your custom gyro. I think with that arrangement you might get the vertical CG inline with (or close to, at any rate) the vertical CP.

There is an irreducible problem here, in that you want to keep the thrustline up and away from the water (water is hostile to propellers), but you want to keep it on the centre of gravity and centre of pressure for the greatest stability.

A tractor gyro might work better on floats.

cheers

-=K=-

[twistair]

35 years ago some guys in Riga played with floats. There are some photos and comments at my website at http://twistairclub.narod.ru/ussr/rigaengl.htm
See "Riga AS-2" link.
I also have a short old video of their gyro towed on floats but I failed to reach Tim's ftp://www.prachapter34.com/ website today to upload this video.

http://twistairclub.narod.ru/ussr/images/overkeel.jpg

Cheers,

[Blll]

Hi guys

If you want REALLY lightweight floats the way to go is to use inflatable tubes...ie tubes with diameters on the order of 2 to 3 feet and lengths somewhere in the 6 to 8 foot range..

Think of the material they use for those inflatable dingies/boats...

Now, you to keep then from flexing too much you might want something along the lines of carbon fiber tube(s) running along the top...commerically made carbon fiber tubes are amazing strong and light (much more than you can even probably achieve in even your best effortand not horribly expensive when your just talking a few dozen feet of it rather than hundred of feet...

Imagine your typical helicopter skid except its made with carbon fiber tubes and has and inflated cylinder underneath it....

take care

Blll

[Gordon Gibson]

Yes I reckon the inflatable type would be the first option for floats on a gyro. I have 3.5 years experience flying a helo on floats (500C) and they do effect the Vne, down from approx 115 kt to 80 kt (or we're supposed to stick to that).

Having said that I have never started up the machine while sitting on the water but I'm told I need to allow for 2 - 2.5 full rotations before the tail rotor bites enough to stop it spinning. This problem might be worse under powerful prerotation becuase with a gyro there will be no tail rotor effect at any time. Would be a lot of fun trying though!

Lotus inflatables are good quality floats with different sizes made for various weights of aircraft.
The lower drag thing would be a concern I'm sure, need some system of 'retracting' the floats up to a higher position after take off?
Thanks, Gordon Gibson.

[automan1223]

About 3 weeks ago I spoke with the new owner who bought the skywheels operation. His name escapes me but according to our hour long phone conversation he took a year off and successfully worked out a gyro on floats, equipped with scuba equipment and all sorts of neat stuff for working off of the water. He mentioned that the positioning of the gyro was key. He said the you had to mount the gyro way way forward of where you would normally put an aircraft on a set of floats. He said once he got all the stuff worked out the gyro not only flew good but great. I mentioned Jim Vanek story and the other Ken Brock stories I have heard over the years, he knew them all, and then went in a new direction.

He also mentioned that he was no longer in production of the skywheels as other movie related production millwork required all of his available workshop. This is killing me he has an unusual last name, I will dig it up somewhere. Anyway I expressed surprise that he got it all to work out and did his homework he said it was not impossible and that he might come out of hiding and write an article about it. I am not making any of this up but he did get me excited because we have more open water and places to land than airports. He lives in California and is associated with Dan Donley and chapter 1. Someone jump in here and finish this off.

[rtfm]

Hi,
It would be really neat to be able to equip a gyro with floats, and your conversation sounds as though it might actually be the start of something useful. I have no burning desire to prove the doom and gloom prognostications of those who consider this an ill-advised move - but on the other hand, I'd really like the utility that a safe gyro+floats would provide.

I, for one, and very eager to find out more...

Keep up the good work
Duncan

[Gordon Gibson]

Duncan

One of NZ's 'doyens' of gyro flight, one Ray Fuszard, flew a lot around Coromandel in the 70's with his Bensen with plans-built Bensen floats thereon.

He told me once the only problem he encountered was the extra weight reduced performance to the extent that it could only do anything sensible on colder days. BUT, as he took off each time he got liberally splashed by water coming off the front of the floats...combine this with cold weather. He said this was the biggest problem.
He never mentioned anything about handling difficulties.

Thanks, Gordon Gibson.

[weka]

I've heard the Butterfly ultralight is suppose to have floats as one of the extras available?

[quadrirotor]

the best Butterfly on floats!
http://www.flyingflea.org/

[jucie]

rtfm:"The only reason for prerotation is to shorten the takeoff roll. But if you're trying to take off from a river, your runway is MILES long... who needs prerotation at all? Just crank up the prop, sit back and taxi across the water into the distance until you reach sufficient RRPM."

Not really, Duncan. Rotation is a requirement for auto-rotation (funny, it isn't?). Auto-rotation effect is to accelerate a rotor that is already spinning. If you don't spin the rotor to begin with (using a mechanical device or your hands) you can taxi all day long and will never reach sufficient RRPM. You can damage your blades if they flap, however (they will, sooner or later).

[GeorgeHedinger]

Food for thought from a newbie. Weight? Drag? Why two pontoons? Why not
just one ponton under the keel with a couple of small outriggers where the
main gear used to be? Should be considerably less weight and less drag too.
AND, less drag in the water on takeoff since the outriggers would come up
out of the water almost immediately.
Just an idea.

[Doug Riley]

Monofloats with sponsons ("outriggers") have been done on gyros before. Full Lotus makes an inflatable system of this sort.

The key to flight safety in a float project is the same as with any other major airframe mod: identify the change in airframe moments caused by the new items. Then make sure that these new moments are fully opposed ("cancelled out") by other moments in the opposite direction. The opposing moments must be reliable. They must NOT be generated by the rotor, since its thrust comes and goes and moves about in flight. H-stabs, as well as high pilot seats and other adjustments of ballast position are appropriate sources of opposing moments.

[Greg Mitchell]

Weka,

Larry Neal has not, as far as I know, tested out the floats for Butterfly/Monarchs but intends to do so.

Regards,

Mitch.

[Greg Mitchell]

G'Day Doug,

Your posts are a wonderfull source of technical information. Doug do you have any pics of the Monofloats with out riggers? Thanks.

Mitch

[thirdy8special]

Curran3,
If you want to get rid of those floats, let me know.

[Doug Riley]

Mitch: I saw one at Oshkosh 1972. I took a picture of it, but the print is probably pretty well buried in some drawer. It was a fiberglass monofloat of a rather sophisticated shape -- all compound curves and nicely tapered. It looked like one float taken from a larger aircraft. The sponsons were of similar construction on round-tube outriggers.

Again, any float system (mono-, dual- or boat-hull) will cause potentially very dangerous nose-down pitching tendencies in a standard pusher gyro. You need to get a handle on these tendencies and re-design the whole ship to eliminate them. Failing to do this can, and likely will, cause a serious crash. It has for several people.

[Greg Mitchell]

Doug, Thanks, I'm sure you are correct in that a full re-design would be required. Alex from Russia posted a web link on Oz Forum, you Guys may have it already, interesting tractor gyro with sprayer set-up. There is also a Pic of Gyro glider with dual floats.
http://twistairclub.narod.ru/adel/index.htm.
Cheers.
Mitch.

[jucie]

Alex from Russia posted a web link on Oz Forum, you Guys may have it already

I don't. Do you have the link, Mitch? Thanks.

[gyrodes]

I remember that there was a bloke in North Queensland in ozz that had a set of floats on his gyro but the mag is about 250 miles away at the moment so I will find the info when I return to work there next week somtime. On second thoughts aussie Paul may have that info when he gets back to his home base. Paul Bergan-Abbot has some pics in his book about Benson so have a look there. gyro des

[Greg Mitchell]

Jucie, Sorry Mate must have typed it wrong, go to General Discussion and look for Gyros on Ag Spraying, Twistair...Alex has posted the link there.
Mitch.

[gyrodes]

Sorry ppls the book is titled "A Dream of Flight" by Dr. Igor B. Bensen, P.E. published by The Abbott Company , USofA. gyrodes

[skypuppy]

Tom, how is the construction of your Barnett coming along? Which model are you working on?

[automan1223]

Doug,

I spoke with Jim Lezile a few months ago, (excuse spelling ?) I actually found the pra mag article this weekend, an issue about 2 years ago that did a prelim on his amphib setup. He says he has worked it out and one secret was to move the gyro way forward on the floats. I am guessing that the drag on the front becomes minimum when nose down and the rear of the floats acts like a hs and rights the fuselage pivoting it back. I had been drawing out some ideas, because I am surrounded by water and it could be cool to operate off of the river.

Jonathan

[Doug Riley]

Remember that pitchover can be caused EITHER by a low center of drag or a low CG. Moving the gyro forward on the floats doesn't change the HEIGHT of either one.

[JohnEvans]

I confess! I'm building a float gyro. I live on a salt water lake, and since getting a float endorsement a few years ago I've wanted to fly off it. We've looked at various configurations, including retracting the floats. Recently I saw a video of a French attempt using a Magni, the prop obviously copped a dreadfull beating from the spray, they didn't show any pictures of it afterwards.
Quite a few years ago an ASRA member, Bill Lockridge had one he flew around up at Thursday Island, another member, Bert Larkin showed me the remains of one he flew many years ago. Both of these were pushers, in the years before the obsession with CLT began. I gather they were flown with considerable caution so far as speed is concerned!
There appears to be a long history of Gyro gliders on floats, we even had one in South Australia which had the towing boat go under a bridge.
My project is a tractor, built in wood to avoid corrosion, obviously it will have qiute a powerfull HS.
It's going to be an interesting project!

[GyroRon]

I don't understand why someone that wants to fly off water would try to re invent the wheel so to speak, when there is many successful Trikes and fixed wing ultralights that are easy and cheap to buy and fly.

Most gyros are already just barely powered, in other words just have enough power to fly with only wheels. Add the simplest float system and you have added another 60-70 pounds and alot more stuff to drag through the air.

It is a cool dream, but not a practical one by any means.

[Skysailor]

Looking to buy strong and simple gyro for the beginner without engine. Gyro must to be good for engine Honda 105 h.p., 95 kg., prop. 3 bl., 68 inch. Thank you for any advace.!!!

[Aussie_Paul]

....this is a pic from 1982. An Air Command fitted with floats. Somewhere I have a better pic but at the moment I cannot find it!!!!

This pilot stopped by to see me for a BFR back in the early 90's, and gave me a couple of pics of his float gyro. The area he was flying is up the North of Oz around Thurday Island.

Aussie Paul. :)

[Canadian Rhino]

Ron, up where I live there is nothing but trees and water. If you lived here wouldn't you want to be able to land on water? By the way you would not even dream what the fishing up here is like Sorry your wheels just wont cut it up here!. Just my .15 cents worth :D

[GyroRon]

Rhinoman, me thinks you are building the wrong kind of aircraft if al you got is trees and lakes. Me thinks you should have been building a Murphy Rebel on Floats, or something like a Rans S-6 on floats.

On a different subject, I got a copy of the newest Sportcopter video and there is a segment of Jim flying off a lake with his Sportcopter. Looked quite doable, but I still think the added weight is too much for many gyros and the added drag down now can make a thrustline offset much much worse if that kind of thing matter to you. There is aerodynamic issues I believe a set of floats places on a gyro that are not favorable.

[KenSandyEggo]

Someone once said: "Floats on a gyro are good for marking the spot where the pilot is hanging upside down underwater."

[Paul_in_Ohio]

I was just thinging the same thought, Ken.

[davreich]

Hi,
I thought I remembered something in the forum about a pitbull on floats jout of Seattle. I did a search and found in under general discussion - gyro flipps.

[Canadian Rhino]

I did not choose the Sparrow Hawk with intent to add floats mind you that would be a nice option if they ever do engineer that as an add on. The reason I chose this aircraft is very simple. An engine failure up here is fatal in a fixed wing or helicopter where as a gyro can always find a small spot somewhere to set in even if it is a cut line or small bit of swamp. One time I experienced a failure on the prop pitch mechanism on a 185 on floats over bush country and will never forget how fast them trees are going by as the cheeks of your ass are holding you to the seat. The pitch is controlled by oil pressure through an extra gallery on the end of the crank shaft and through time can clog up due to centrifical forces. 1950s technology--no thanks! no more!