I like this video too darn much….it's Pete's fault…..

[RotoPlane]

Pete posted this video some time ago and I'm still watching it….both for the gyro and the music (Shakira - "I have a feeling inside"). Perhaps some didn't have a chance to see it, so I thought I'd put it up again. The gyro (in Spain) performs so well, but that may be due to its light-weight pilot. I'm hoping mine rotates that fast and lands that slowly.....

http://www.youtube.com/watch?v=6vPnaCJyyhc

[Earthboundmisft]

Hey Ed, I would love to see more photos of the Girabet. Also material details, etc.
Thanks, Mike.

[RotoPlane]

Michael - If you place "Girabet" in YouTube's search....a bunch of videos will come up with this type of gyro in them. Unfortunately, I can't speak Spanish....sorry, that's all I know.

[Earthboundmisft]

Thanks Ed, I found more info after I posted. I like that frame design, very clean.

[RotoPlane]

I like that frame design, very clean.

Yes...so do I. There's something about curved tubing.....

[aerialvisitor]

Here is a website where you can look at several video's about this particular gyroplane.
http://www.videonico.com/?q=+girabet&select=youtube

Here is a more informative page:
http://www.airbet.net/girabet/i/girabet.htm

Their website is:
www.airbet.net/

Dave

[Earthboundmisft]

Thanks Dave. Mike.

[C. Beaty]

Low speed performance of a gyro is determined primarily by power to weight ratio. The arrangement of the airframe tubes isn’t particularly relevant so long as the designer understands the basics.

Here’s a 1994 clip of a 150 lb. pilot flying a 240 lb. gyro propelled by a Rotax 503.

This was Pier Luigi’s first flight in this gyro; he started out slowly but got the feel pretty fast. We had to duct tape a pillow to the seat back so he could reach the pedals.

http://www.youtube.com/watch?v=NqogAadBzKw

[Terry]

I sure admire your gyro Chuck.

It has little Vstab and adequate rudder working below the torque axes, offsetting mast and rotor mass; and it's greater mass and aerodynamic drag is collected tight to the rotor while using tall gear for ground clearance.

It is a Beatty to me . . . I mean beauty.

Nice video!

But, what do I know. I'm new, never flown or built a gyroplane; but hope to some day.

[aerialvisitor]

Hi Chuck:

I enjoyed the video. The dog and pony show was good too. :)

Dave

[RotoPlane]

I have studied Chuck's excellent performing gyro in several videos and concluded that it would take someone like him to come-up with that design. I think of his gyro as "Sophisticated Simplicity"…..

[RotoPlane]

I just remembered a thought I had some months ago. Pete didn't get all of his gyro knowhow by sitting on a chair swigging a beer….so I've wondered why haven't I seen at least one picture of his gyro(s)? Do you have some pictures Pete, or anyone? I'm nosily-interested, to learn ;).

[Passin' Thru]

I just remembered a thought I had some months ago. Pete didn't get all of his gyro knowhow by sitting on a chair swigging a beer….so I've wondered why haven't I seen at least one picture of his gyro(s)? Do you have some pictures Pete, or anyone? I'm nosily-interested, to learn ;).
Ed, I never owned a camera in my whole life until just this year! I'm just not a picture sort of guy. (If you ever saw a picture of me you'd know why I'm camara-shy!):eek: ,Some of my friends and relatives have photos going back many years, but I don't have a one!
Someone here in PR made some photos of my most recient gyro, I don't remember if they were film or digital. I'll try to find them.

[RotoPlane]

I don't have a clue what most people here look like, nor is it important….only the brain, personally and character matter. Hmmm….I may be saying that because I'm no looker either, well……not now ;). Actually when I am reading one of your posts, I see in my mind "Passin' Thru"'s photo talking. He's one cool dude!

It's not vital, imperative, essential, or terribly, terribly important to see your gyro, but it would no doubt be very interesting and educational for all of us…..even if it looks "normal". Yes, I would like to see it!

[Earthboundmisft]

Without having to search for an hour, can someone refresh my memory regarding the
qualities of a round tube, 4130 mast, like used on the girabet single place?
Interesting frame design. Wonder why you couldnt bend the mast tube rearward to
attach the tailfeathers, with the forward tube added as a weldment?:noidea:

[RotoPlane]

Michael - Looking at one fairly clear video, the main tube looks like S.S., but it may be 4130, nickel plated. The fwd and mast tube appears to be one piece with the smaller diameter aft tube joining the main tube in perhaps a weldment. The top of the main mast tube receives an aluminum head block or bushing. This would be a joint to expect galvanic corrosion, so it would need a good protection barrier.

4130 - Aircraft Grade, Condition N
.035 to .188 Wall = 95,000 psi tensile, 75,000 psi Yield

[Earthboundmisft]

Thanks Ed. I was wondering how a round 4130 mast behaves, versus typical 2x2 T6.

[RotoPlane]

If I understand you correctly Michael….for comparison:

An aluminum 6061-T6, 2" square .125" wall tube would have a .937 sq.in. area (1.12 lb/ft)
So .937 X 45,000 psi = 42,165 psi tensile strength

A steel 4130, 2" round .125" wall tube would have a .737 sq.in. area (2.503 lb/ft)
So .737 X 95,000 psi = 70,015 psi tensile strength
[With AL. .737 X 45,000 psi = 33,165 psi tensile strength (.887 lb/ft)]

A steel 4130, 2" round .065" wall tube would have a .396 sq.in. area (1.34 lb/ft)
So .396 X 95,000 psi = 37,620 psi tensile strength
I think the next step in wall thickness is .083 (14ga)

[Earthboundmisft]

Once again, Thanks Ed! Looks like the 4130 round tube design may have some merit. I like the welded construction. Just wonder if the mast would be TOO stiff, and have poor damping qualities.

[helipaddy]

I think the airframe and mast is 316L stainless, It looks like the forward keel and the mast is of a greater diameter than 2". Looks like a dia of 60mm or 75mm

[RotoPlane]

Yes Padraic, for me it also looks like stainless and close to 3".

Michael - Chuck Beaty's gyro mast tube is 3" dia. with a .065 wall and is 6061-T6. This tube has .600 sq.in. cross-sectional area with 27,000 psi tensile, but remember that without a slider-head, this tube is too stiff. Makes me wonder about the Spain gyro.....

[helipaddy]

I wonder Ed, if the fixing of the tail feathers on Chucks machine at the top of the mast had any effect on mast resonanace which required the slider to fix them? It attaches a lot of mass at the top of the mast. Maybe Chuck could answer.
Maybe the 3" Stainless tube is just the right length to be out of frequency with the rotors?

[RotoPlane]

Well Padraic.....resonance tends to make my head vibrate and I lose data…..

[Earthboundmisft]

AHHH, NOW we are getting somewhere. All that resonance stuff is rocket science.
My design is classic monkey see - monkey doo. Ya gotta wonder about materials other
than 1x2, and 2x2 T6 square. THATS why I was diggin that Girabet design.

Somebody educate me.:noidea:

[C. Beaty]

The most forgiving gyro I’ve ever owned with respect to rotor shake was one built mostly to Bensen B-8 dimensions but with a round 2½ inch 2024 mast tube. No braces and with a wall thickness of 0.120”.

Didn’t know why at the time; 1970s. Didn’t know that a keel mounted horizontal stabilizer is the wrong place either.

Shown here with Hughes OH-6 blades and my $10 Sears prerotator (the flex cable was a Sears extension shaft).

[Earthboundmisft]

Chuck, how about a 2.500in. 4130 mast? What thickness? TOO stiff?
By the way, did Davie kill all the grass around your house?!!
Thanks, Mike.

[C. Beaty]

Way too stiff. Steel has about 3x the stiffness of aluminum for a given size. 2” x 0.065” steel tube has about the same stiffness as 2½” x 0.120” aluminum.

[Earthboundmisft]

Chuck, thank you sir.:hail: