Cierva style homebuilt

[Zack]

Some time ago I ran across a partial Spanish or Portuguese language forum thread via a Google search that was about a Cierva style homebuilt tractor gyro that someone had built, possibly in South America(?). Is anyone familiar with that aircraft, and if so is there anywhere to find out more about it?

Thanks in advance for any info!

Zack

[gyroplanes]

They built one and flew it in Spain. It may have been a restoration.

[HobbyCAD]

Hi There Zack,

What are you referring to, when you say "Cierva Style" Tractor Gyro. The open cockpit front engine, and the 3 or 4 blade rotor system.

If you are referring to tractor homebuilt gyro's, there is the Pitbull kit.

Regards,

Francois

[Arnie Madsen]

Zack

Are you thinking about the 1932 Pitcairn Autogyro which was recently restored ?
I think the Pitcairn was the Cierva machine that was built in America around 1930's.

Rick Whittridge has a good thread with lots of pictures from his airport.
http://www.rotaryforum.com/forum/showthread.php?t=5883&highlight=pitcairn

Nicolas Karaolides has an article on the unfortunate rotor damage during testing.
http://www.rotaryforum.com/forum/showthread.php?t=17505&highlight=pitcairn

Arnie

[helipaddy]

I remember this, It was a wooden fuselage with a Rotax 2 stroke, single seat,tailwheel, with a 2 blade rotor system, I think they rolled it over at some stage. I think there were a few photographs of the gyro in the British Rotorcraft Association magazine a few years ago. It looked really nice.

[Zack]

AH HA!!!! Took a lot of searching, but I managed to track down the original thread where I saw this.

http://www.foroswebgratis.com/tema-autogiro_tractor-35586-206322.htm

I cannot read a word of it, but if you scroll all the way down you'll see some photos of the homebuilt tractor gyro that I am referring to. Looks like the thread is dated 2006, and I'm curious to know what became of the aircraft.

Thanks!

Zack

[helipaddy]

Yep, thats the one I was thinking of

[Zack]

I'll try and post a couple of the photos directly...let's see if this works.

http://i730.photobucket.com/albums/ww307/ZacharyBaughman/100089fuselaje4x.jpg

http://i730.photobucket.com/albums/ww307/ZacharyBaughman/100297R2_001.jpg

Now you fellas (and ladies) are a pretty knowledgeable bunch - from the limited detail in the photos here, is there anything strikingly wrong with the design that you can see? I'd love to build a tractor gyro, and it looks like this one is fairly basic in overall design. While I'd love to build a Little Wing, I do not have the time or money to become proficient enough with welding to take on a project like that. This however looks do-able. Any thoughts? Thanks!

Zack

[Alan_Cheatham]

There is an article about that gyro including several color pictures in the April 2000 issue of Rotorcraft magazine.

[Zack]

There is an article about that gyro including several color pictures in the April 2000 issue of Rotorcraft magazine.

THANK YOU Alan - very much appreciated!

Zack

[karlbamforth]

There is an article about that gyro including several color pictures in the April 2000 issue of Rotorcraft magazine.

Anybody with a copy willing to scan and post for us?

[WHY]

Hi Zack

You asked about anything wrong with the design, well it looks like they really did their homework on this model, with maybe one exception, one of the post here stated that they thought it had a two stroke engine, well from the photos it looks like some kind of a Vee twin???? Well if this is true they may have there GROUND weight and balance near OK but if this is a two stroke engine then it looks like they will be quite tail heavy ON THE GROUND AND THIS WOUD MAKE GROUND HABDLING VERY DIFFICULT.

If you got a look at the side profile of the real full size gyro of this model you would see that it is very close to the same lay out as the full size model, "BUT" the full size model used a radial engine.

Maybe some of the other posters here can clear this up. Personally I love the tractor and this one is a beauty.

Tony

[Arco]

This a desing done by Victor Merino. It is spanish guy member of the AAE http://www.asociacionaviacionexperimental.com
this is the spanish version of the EAA. The drawings of that autogiro has been published in the magazine of the AEE.

[C. Beaty]

If limited to a seesaw rotor, a better model would be a Kellett KD-1 with its single steel tube rotor mast. Rigid rotor pylons and teetering rotors don’t get on too well.

And as is the case with any tail dragger, the main wheels should be no farther forward of the CG than just enough to keep the machine from nosing over when the pilot exits. That reduces the inherent tendency to swap ends when the tail wheel lifts.

[Minnesota_Mike]

Here Ya' go guys...all translated thanks to google!

http://translate.google.com/translate?prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.foroswebgratis.com%2Ftema-autogiro_tractor-35586-206322.htm&sl=es&tl=en&history_state0=

Hope that helps Ya' out.
M

[Alan_Cheatham]

Anybody with a copy willing to scan and post for us?

Well, I have a copy and would be willing to post it here IF I knew it was OK as it is copyrighted by the PRA.

[Alan_Cheatham]

Here's one more picture of this machine as well as two of another similar machine.
.

[Alan_Cheatham]

If limited to a seesaw rotor, a better model would be a Kellett KD-1 with its single steel tube rotor mast. Rigid rotor pylons and teetering rotors don’t get on too well.

Kellett eventually added triangulation to their mast tube after a failure (I don't know if it was in flight or not). What effect this triangulation had on mast rigidity is uncertain as I haven't been able to find any details of how it was implemented.
The downside to tractor gyros with a centrally mounted rotor mast is it's right in you line of sight, not something I would tolerate. I've always wondered if Pitbull pilots end up temporally cross-eyed after spending some time in the cockpit.
.

[C. Beaty]

Flexible rotor masts most likely exacerbate ground resonance problems.

Control of ground resonance in drag hinged rotors requires damping not only of the drag hinges but also about any spring between rotor and ground.

[John Stahl]

Chuck Beaty

Why do the tractors like the C-30 have winglets on the horizontal stabilizer?
What I am thinking is there is not enough vertical stabilizer and the gyro would ground loop on take off. By adding the winglets it helped to prevent ground looping.

Is there any other reason for the winglets?

[C. Beaty]

Rotor clearance considerations limit the space available for vertical tail surfaces; therefore the dorsal fins above and below the fuselage as well as the winglets.

[John Stahl]

Chuck
Would that help prevent ground looping?
I have a pitbull and ground looping is an issue

[C. Beaty]

A tail wheel airplane, John, once the tail wheel is off the runway is like a tail heavy automobile. If you’ve ever driven a Corvair or an overloaded pickup truck, you know the feel. Once started on a curved path, centrifugal force acting on the CG that is behind the main wheels tends to tighten the curve, the beginning of a ground loop.

Certainly, the more vertical tail surface that can be placed in the propeller slipstream, the more power you have to resist ground looping.

[John Stahl]

Thanks Chuck
With the information you have given me in post # 14 and #23 you have given me the information I needed to help tame my Pitbull.
Dang I will have a hard time sleeping tonight because I will be thinking how to improve the ground handling of my bull.

[WHY]

While these gyro's are beautiful examples of the style of the thirties, a much more simple "airframe" could easily be adapted from a modified VP-1 Vollksplane fuselage or a KR-1 fuselage. I know we in the gyro community do not have the membership base that one would find in a organization like EAA but it sure would be nice if we could come up with a top notch "wood worker" ( does Stan Foster have any twin brothers?) that could take one of the fixed wing fuselages, of which there are many, and do a simple conversion so as to give the community a idea of what can be done. I realize that the number one draw back to this idea is that a lot more work is involved in a tractor than the basic Bensen style frame but just look at the end results. There would however need to be a whole new understanding of weights and balances for this design or style as you have a more critical balance on the ground than with a tri gear, but as always this takes a lot of motivation to takle a project like this.

Tony

[Alan_Cheatham]

Any "adaptation" of an existing airplane airframe, especially a wood frame that is glued together, must be approached with extreme caution and with the proper application of structural engineering. The load intensity, direction of forces, and vibration a rotor and mast imposes on an airframe can and probably will be significantly different than what a wing attachment would be. It's likely better to start from scratch with a purpose designed airframe than adapting one.

[Jean Claude]

In my opinion the tractor is better because
1) it will install a larger propeller: better thrust at low speed flight.
2) it allows you to easily pick up flow behind: lowest drag
3) It is easy to put the thrustline on the Center of Gravity
4) much less propeller noise in the air smooth from front.
5) the engine give an protection to le pilot in the event of an impact against an obstacle.
6) the propeller no cut all that bad luck falls

Disadvantages?
1) Visibility: ROTAX 503 reversed and instrument panel narrow is no more annoying than other "cut wind". The big mast in front of the eyes can be replaced by two small side masts.
2) tendency to looping ground. Should not be copy the tail wheel aircrafts: They were designed for little authority because the rudder, large and far behind, is efficient. Here, on the contrary, there must be a very great authority and very little movement. A system Flight / ground could facilitate taxiing.

[brett s]

I've always thought one of Graham Lee's 7/8 scale Nieuport 11's might make an interesting tractor gyro conversion.

[WHY]

Hi Brett

I agree about the Nieuport 11 fuselageas being a good candidate for a conversion, but I do have to agree to some extent with Alan's comment about the necessity of doing a thourgh research of stress and load points for the mast/pylon and for the new location of the main gear whether tail dragger or tri gear, with that said I think the remaining features of the fixed wing fuselage would be usable with very little mods.

But as Chuck has pointed out that a whole bunch of tail surface and rudder surface are a good idea on the tail dragger, I think the Pitt Bull would do much better if it were to have a tail structure like the Kellett with the inverted rudders providing much more control with a low profile.

There is one thing that must be taken into consideration for sure, if one is considering a conversion and that is there is no way a gyro is going to perform well on the same horsepower that the fixed wing craft did, they just do not have the efficiency, it's going to take a lot more power.

Tony

[TracyHansen]

Greetings to the group. I am a new member from Portland, Oregon. I have a lot of hours in open frame gyros and I am a private pilot rated for single engine land, Seaplane, and Helicopters. I am the owner of a 450 HP Stearman Biplane and a Cessna Turbo 182.

I have had a dream for many years to build a Pitcairn-style autogyro based on a biplane frame. I have the capability in my business to fabricate, weld, and powder coat but I would like to collaborate with other like-minded folks on such a project.

The biggest obstacles, as I see it, is the design and engineering of the rotor head and rotor blade systems.

Anybody else out there have the same burning desire?

Tracy C. Hansen
Hansen Architectural Systems, Inc.
503-356-0959

[Doug Riley]

Hey, Tracy, nice to see a post from you.

[Alan_Cheatham]

I have had a dream for many years to build a Pitcairn-style autogyro based on a biplane frame.

Tracy, what scale are you talking about here, full scale as in Stearman size with a large radial engine, or something smaller?
.