Pitcairn v. Kellett

[jehicks87]

Hey guys, it's me again! Trust me, yall may eventually get suck of me. :rant:

Anywho, in my quest for the "one" to shrink and build, I have found a design I love love love: The Kellet KD-1. Beautiful, flowing, graceful lines. Goregeous.

However, I have noticed ALOT more information on Pitcairn and his models. Could this simply be owed to the fact that pitcairns were basically re-badged Cierva's (I mean, how to you better an original?) or to the fact that Pitcairn were simply better? One thing that strikes me as funny, not funny ha-ha but just funny, is that the quintecential FW Airmail craft is a Pitcairn, while the main "claim to fame" kelletts have is the Airmail KD-1.

I'm kind of tired, not used to being up this early and certainly not being online this early, but I was just wondering what you guys thought... more of actual first- or second-hand experiences with either manufacturer or stories told from people you personally know or viable historical-isms (sorry, brain is not working right now). NOT just speculation.

As much as I'm afraid this is going to turn into a Ford VS Chevy type debate, I'm hoping for some solid information that can help me decide... what was "America's" tandem-seat, open cockpit Autogyro? Pitcairn, or Kellett?

[WHY]

I think you will find the Kellet KD-1 to be the top of the line in autogyro technology for it's time period and in a production model. there were some proto type models of Pitcaiirn produced that were quite advanced but not in production.

The KD-1 is a good enough design that it is among the top choice of RC modelers

Tony

[Vance]

I would recommend the book “Autogiro, The Story of the Windmill Plane” by George Townsend

You will find lots of food for thought.

Thank you, Vance

[barnstorm2]

I would recommend the book “Autogiro, The Story of the Windmill Plane” by George Townsend

You will find lots of food for thought.

Thank you, Vance

and From Autogyro to Gyroplane by Bruce Charnov.

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[Zack]

Just to set the record straight, Pitcairn Autogiros were certainly not "rebadged" Cierva designs. The rotorhead may have been copied, but the aircraft themselves were completely new designs. I think you are able to find more information on the Pitcairns for two reasons: more were built than the Kelletts, and they were used in more commercial situations, particularly the PCA-2. I really don't have an opinion on which manufacturer made the better Autogiro (I like them all), but I'd wager that the PCA-2 was built in higher numbers than any other type at the time and flown by more famous pilots than any other - Amelia Earhart, Lindbergh, Johnny Miller, Blanche Noyes just to name a few.

Zack

[Vance]

My personal favorite is the Pitcairn PA-34 built for the Navy as the XOP-2.

They had a full NACA cowl over the 420 horsepower Wright R-975 and were very streamlined.

They were big and brawny and looked purposeful.

I also like the Pitcairn Pa-33, very similar, but with a more streamlined landing gear.

Both the PA-33 and the PA-34 had a direct control 50 foot 3 blade rotor without supporting wires.

The disk loading was low for the times at 1.3.

They were both supposed to have a cruse speed of 115 and a top speed of 140.

They both had a 1,000 pound useful load and had a dry weight of 2300 pounds.

Thank you, Vance

[Alan_Cheatham]

Anywho, in my quest for the "one" to shrink and build........................

Do as you have been doing, the research as there are many good ideas from past efforts, but if you plan on "shrinking" one of these old tractors down you will be building a completely new gyro design with it's own unique qualities, and many times will not replicate the full size ships traits.
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[magilla]

Look at the airframes that they use for the 3/4 scale WWI fighters, use the fuselage, and attach an Air Command rotor system with DW blades and Wunderlich pre-rotator.

It would look almost exactly like the gyro you have on your avatar.

[jehicks87]

Hey, LTC! Thanks for dropping by! I sent you a pm on here, I don't know if you got it or not... I'm SPC Hicks, 15T, now with the 1/185th. I worked under you and CSM Bluford at the AASF the past few summers, when you were the commander out there. I talked to you once or twice, and even remember you showing me your prop. How's the gyro coming?

Alan, thanks for the food for thought. I'd already considered that, as the CG and drag profile would change. I guess there's more to it than that, though.

The thing I'm not crazy about with the ueber-popular Pitcairns is the fact that you need moving air over the control surfaces. If I were to use these designs as my base and then put a fully-articulated rotorhead on top, the wings would have to go and then it wouldn't be as close to the original as I would like; though I do think the Pitcairns are beautiful in design, and really enjoyed the restoration of the pitcairn one of the members here started a thread about (I've been a creeper for a while... lol)

Another thing I must consider before diving head-first into the Autogyro pool is construction. My dad agreed to help me with a Pietenpol Aircamper by St. Croix that I really want to build, mostly to get construction principals down in regards to wooden aircraft.

And thank you all for the suggested reading. I appreciate it all... I think this is a good "get'cha thinkin" thread.

[Vance]

The PA-33 and PA 34 don’t have wings.

They gave those up when they went to a fully articulated head.

Good luck on your adventure, Vance

[Jim]

You can purchase plans for the Kellett on microfilm for $ 100 from the Smithsonian, but have to sign a waiver that you will not reproduce it.

Jim

[Alan_Cheatham]

I see no reason to build a gyro with wings unless you just like looking at wings, and if that is the case just build an airplane.

And a word of caution. Rotorcraft can subject their airframes to considerable and constant vibration and in ways that airplanes don't so that needs be considered when evaluating airframe materials and methods of joining them. For me, I have chosen to go with a welded steel tube structure in my tractor.
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[Alan_Cheatham]

You can purchase plans for the Kellett on microfilm for $ 100 from the Smithsonian, but have to sign a waiver that you will not reproduce it.

Jim

You may want to look up the patent drawings for the various old tractors too, free off the internet and contain some interesting design details, one that I noticed was rubber dampers in the end of the control rods.
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[jehicks87]

I see no reason to build a gyro with wings unless you just like looking at wings, and if that is the case just build an airplane..

The reason they did that was because the control was actually derived from air moving over the control surfaces, much like an airplane. That is no longer the case, so long as you have a fully articulated head, such as the Cierva C.4 and later models, or the kellett KD-1.

You can purchase plans for the Kellett on microfilm for $ 100 from the Smithsonian, but have to sign a waiver that you will not reproduce it.

Jim

I wonder if a scaled-down version would be considered a "reproduction"...

[karlbamforth]

I doubt a scaled down version could be considered a reproduction.

Besides if you modernised the structure a little it would be a different aircraft.

I know you are thinking of a fully articulated head but you might be better off starting with a modern 2 blade gyro head rather than all the R &D of a new design.

Another way may be to start with Littlewing drawings. Its already a 2 seat tail dragger gyro. A few plywood formers will change the fuselage shape. Remove the cockpit roof, a little modification to change the looks of gear and cowlings and we almost there.

I am genuinely interested in building a replica of an old style design so keep in touch.

[jehicks87]

I certainly will, though this project may be a little ways off... my dad and I have always talked about building/owning an airplane since I was a little kid. My interests have pushed me towards rotorcraft; he distrusts them. He had a close call monday night, we ran him to the ER, and the doctors were pretty stunned: a 95% blockage in his heart.

After this reminder of how precious little time we have, I finally talked him into committing to a project. His one stipulation: Fixed Wing! lol. I even had to talk him INTO an open-cockpit design!!! Can you believe that? The pietenpol design is almost exactly what I like in a FW design, so I nailed him down to that one... hopefully.

And, if it doesn't violate forum rules, I'll be posting our progress on here when we actually begin construction, and all the while using my experience with this project to better facilitate my ultimate goal: a Golden Age Autogyro. The kellett is the forerunner in my thoughts, so that's the one I think will be on the plate. I remember the first time I ever saw an autogyro EVER; it was the newsreel about the world's then-first (and now, only) autogyro airmail route. Lately I have discovered the gyro in the reel was a modified KD-1. Cool, huh?

But, onto a point you raised in your post, what is the difference between the rotor design most gyros use now, and those used in Fully Articulated systems back then? Don't modern gyros have heads that tilt fore-aft and left-right?

I may be misusing the term "fully articulated" so to clear that up I do not mean the type used by helos and the like; I was more referring to what I thought modern gyros used. If I'm wrong, I would like to learn the difference.

[Alan_Cheatham]

The reason they did that was because the control was actually derived from air moving over the control surfaces, much like an airplane. That is no longer the case, so long as you have a fully articulated head, such as the Cierva C.4 and later models, or the kellett KD-1.

Correct, once they figured out how to use the rotor to control attitude then the wings came off, or actually the ailerons and elevator.

Something of interest here is that Ron Herron used a combination of controls in his LW-2 Littlewing tractor taildragger where roll was controlled by tilting the rotor/head from side to side but pitch was controlled by oversized elevators. His comments indicated the elevator control for pitch was "instantaneous and absolute" and in his promotional video he does a power off landing to demonstrate how the elevator was still effective at low air speed. The downside to elevator control was not being able to tilt the rotor flat and that caused ground handling problems, especially in windy conditions. If one studies the patents for the winged Cierva gyros they show a foot pedal linked to the rotor that would tilt the head flat, I assume to fix the above problem and give greater rotor to tail clearance for prerotation.

Another way may be to start with Littlewing drawings. Its already a 2 seat tail dragger gyro. A few plywood formers will change the fuselage shape. Remove the cockpit roof, a little modification to change the looks of gear and cowlings and we almost there.

That's basically what I have done with my tractor, eliminated the cockpit roof and gone with a tripod mast, it now looks like a gyro version of the Rans S-9. Although certain aspects of it's design are based on the Littlewing plans such radical alteration to the fuselage structure has necessitated a structural analysis.
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[karlbamforth]

Alan,

That sounds like a very interesting project.
Would it be possible to post some pictures of the build

[Alan_Cheatham]

Alan,

That sounds like a very interesting project.
Would it be possible to post some pictures of the build

Sorry, not until she's finished, then I will post lots of detailed pictures. I do plan on posting soon about some tools I have built to make her, just waiting on another "bun in the oven" to be delivered first. Mystery intended.
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[karlbamforth]

Ok thanks Alan,

Time for me to dig out the Solidworks CAD program again. :D

[jehicks87]

Something of interest here is that Ron Herron used a combination of controls in his LW-2 Littlewing tractor taildragger where roll was controlled by tilting the rotor/head from side to side but pitch was controlled by oversized elevators. His comments indicated the elevator control for pitch was "instantaneous and absolute" and in his promotional video he does a power off landing to demonstrate how the elevator was still effective at low air speed. The downside to elevator control was not being able to tilt the rotor flat and that caused ground handling problems, especially in windy conditions. If one studies the patents for the winged Cierva gyros they show a foot pedal linked to the rotor that would tilt the head flat, I assume to fix the above problem and give greater rotor to tail clearance for prerotation..

yes, but didn't the LW-3 move to a fully articulated system, like the one for on the later model ciervas and kelletts?

[WHY]

Hi Alan

Sounds like you have done with the basic Rans S-9 style fuselage somewhat the same as I have done with the 'TEXAS PARASOL " fixed wing fuselage.

Bought a "Texas Parasol'" project and paid a bundle for it only to decide the workmanship was such that I would not even taxi it let alone try to fly it, so now I have a almost brand new fuselage with the mods made as I re-made the fuselage (have about 4 pieces of aluminum form the old fuselage in the new one.

The Texas Parasol is constructed from 1/8 by 3/4 angle aluminum and riveted, I have added larger angle at stress points like firewall and mast attach points and landing gear points. The aluminum has turned out to be much heavier than I expected, your welded 4130 steel will be much lighter but I cannot weld worth a darn to went with the rivet aluminum.

Have had this on paper and in mind for about 18 years and this fuselage under construction for about 2 or 3 years so there is no big rush. Last year because of health problems had to nearly stop the building so am now only able to get about a hour or two a month in which reallys slows things down. Am working on the motor mount for a re-drive 2180 VW for a power plant right now, what are you thinking about for a power plant.

Have not posted any pictures on the forum since I was afraid some one might think I knew what I was doing and try to follow it, have already made some expensive mistakes but keep on going and yes the conversions sure do require some stress analysis and changes especially in transfering stress and load from the mast to the total airframe.

Tony

[Alan_Cheatham]

yes, but didn't the LW-3 move to a fully articulated system, like the one for on the later model ciervas and kelletts?

Yes, he went to a fully tilting head design but mainly to solve the ground handling problems in wind, not because the elevator caused any problems. In one post Mr. Herron did say it would be possible to have a mixed control system, both elevator and rotor tilt, for pitch attitude control but said it wouldn't be worth the mechanical complexity for the added benefit.

One plus for the elevator only control for pitch on the Littlewings was less risk of a tail strike with the rotor at low rotor rpm because the head doesn't tilt back. With the conventional tilting head control on LW-3 and later models rotor management at low rpm is very critical because it will chop the tail if allowed to. Andy Keech warned of this in an email to my friend when we were building an LW-5.
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[Alan_Cheatham]

Hi Alan

Sounds like you have done with the basic Rans S-9 style fuselage somewhat the same as I have done with the 'TEXAS PARASOL " fixed wing fuselage.

Tony

Tony,

A few years ago I was browsing Barnstormers and cam across a Texas Parasol project for sale and wondered if it could be converted into a gyro, I even saved the pictures from the listing. A short time later you posted on the forum about having purchased that same aircraft to convert to a gyro, small world.

Although I've certainly used design ideas from the Littlewing and Rans S-9 my ship is structurally an all new design, and designed from ground up to be a gyro. The hardest part of the design is my own unflinching requirement of not having any rotor mast or prerotator shafts blocking my view. This has required me to design a tri-pod mast and unique prerotator as nothing off-the-shelf was useable.

Welded steel is my preferred choice for a fuselage core and I have the skills and equipment to do so, but after spending 350 hrs working an LW-5 several years back I had to build some special tools to make the tube notching and welding easier and less stressful. Although I'm a skinny guy and more flexible than most, TIG welding the LW-5 fuselage turned me into a human pretzel, both physically and mentally. :wacko:

Oh, here is my engine being "bench run".
http://www.rotaryforum.com/forum/attachment.php?attachmentid=49132&d=1220671133
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[jehicks87]

Tony,
Welded steel is my preferred choice for a fuselage core and I have the skills and equipment to do so, but after spending 350 hrs working an LW-5 several years back I had to build some special tools to make the tube notching and welding easier and less stressful. Although I'm a skinny guy and more flexible than most, TIG welding the LW-5 fuselage turned me into a human pretzel, both physically and mentally. :wacko:
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You TIG'd the whole thing? :hail:

I can't even butt weld two flat panels of Alum with TIG... give me stick or mig and I'm a god, though... and humble, too :lol:

Is your new design based on any historical design, even just appearance-wise, or is it something COMPLETELY completely new?

I'd be more interested in hearing about the complexities and detriment/benifit of fore-aft fixed v. tilt heads, if you could spare the insight.