Floats on a gyro?

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

Floats

Floats

rtfm said:

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

Click to expand...

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.

re: Floats

re: Floats

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

Actually, prerotating becomes a problem also, I believe.

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 )


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!!

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

barnstorm2 said:

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!!

Click to expand...

Go for it, buddy!

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.

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.

Gyros on floats

Gyros on floats

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.

Hydro Copter

Hydro Copter

Another shot

Coming up to speed

Coming up to speed

Another shot

Last hydrocopter picture

Last hydrocopter picture

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"

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

Those pictures bring back memories, Tom.!!

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.

rehler said:

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.

Click to expand...

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=-

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.



Cheers,

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

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.

Skywheels Guy

Skywheels Guy

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.