While a mate was flying his Pico cub at the field, I was wondering if we could make the equivalent thing for autogiros. Something cheap, easy to build, and made of foam.
I thought we could make a "Pico Cub" or "Cessna EP trainer" fuselage and attach with rubbers a rotor system made of lightened plywood, but then comes the problem: how do you make the blades?
Do you think all-balsa blades would work (I just dont want to spend hours making them)? 10:1, 4mm thick Clark Y should work fine IMHO. Please, suggestions and comments are very welcome.
I just can't wait the summer to come and the final exams to go
If I get my hands on a flight pack I'll maybe make a parkflyer/gyro combo.

Here's a couple of pix of an indoor D.C. gyro I found somewhere on the web...I think it was done in France. I kept them because of the blade construction and the clever D.C. control linkage. Hope it helps you "get the juices going."

ps: Make your blade airfoil as close as possible to the SG6042. It autorotates easier and creates more lift than a Clark Y, IMO.

Next pic:

Thanks for the pics, Dickeybird - they helped a lot on giving ideas onthe control system

Anyway, I wasn't thinking "that" small. Let me explain it a bit...
I thought a good way of letting people start with autogiros would be making them more user-friendly. This means you must make an autogiro that could easily be flown and built by everyone, yet a wingless, real autorrotating machine.

Following this thought, I found the Pξco Cub to be the perfect choice for many reasons: it is easy to transport, it is a slow flying airplane (fewer crashes, more reaction time), it's very cheap, and easy to build.

I planned to design a a pylon the SPAD's style, and then post some plans in case it worked fine, or at least a wood pylon that you could build with a few common tools.

My problem? I have no Pico cubs.... However, I found someone who has, although he has only been once flying in my "club". I think I'll make a foam "Coyote" the same fuselage size as the Pico Cub, and try what happens. The problem is what has already been said, how do you do to design an efficient (fast, simple, easy) method of building blades? I've seen a post regarding the use of coro.... Its a pity it doesn't apply to small machines!

Hi,

In answer to your all balsa blades. Yes, they will work good. I have flown several gyros with just balsa and no covering or paint. However, I did add some lead shot in the tip of the blade. Adds a lot of stability and keeps the blades from flexing. I also agree, use the SG6042 blades profile. Make your Clark Y blades and use something like a dremel router or a small power hand planer to cut the under camber.

Phil

Further to the comments on the SG6042 vs the Clark Y: The SG6042 is a bit thinner (memory says something like 11% vs 12+% for the Clark Y). Since autorotation is dependent on having minimum drag, the thinner profile helps.

However the profiles of the front half of the Clark Y and the 6042 are almost superimposable. (Except the greater thinness of the 6042.) The slight undercamber of the 6042 toward the trailing edge is clearly apparent.

Bill

Well if you want an easy to fly gyro for the newcomer then i think its best to have a dual rotor "windmilling" rotor setup

they seem like the easiest to fly

I'm sorry, vtol, but I just can't see why you think its better a dual rotor setup.
In fact, I had not any doubt about whether using a dual or single rotor, for these reasons:
- Dual rotors require twice the number of blades of a single rotor. However, the time and the efforts it takes to make them are not reduced to the half, but the opposite thing.
- They are more difficult to build.
-They are difficult to set up and control using a DC system.
The plan was keeping the plane's controls (throttle, elevator, rudder) and add two extra servos on the pilon for DC control on the rotor.
I wonder could you make it decent glider. I haven't seen many ideas in the "autogyro glider" thread .

JCaste, I think what vtol was referring to was the fixed pitch, sheet balsa bladed side-by-side rotor style 'gyro. The blades are easily built of flat sheet balsa, have no camber to carve and there is no direct control of the rotor head tilt or pitch. The aircraft are controlled by standard rudder and elevator control. I've built a couple, a friend of mine has built numerous versions of them and yes, they are easier to fly, simply because of the orientation issue. I.M.O. they look and fly more like a conventional aircraft in flight than a single rotor D.C. 'gyro does.

I like my new single rotor D.C. 'gyro very, very much but there have been times when I've had trouble with visual orientation and have almost lost it a couple of times when I was talking to a spectator and temporarily lost concentration. Never had that problem with a twin rotor 'gyro.

My 2 centavos worth anyway!

OK, I have to throw my 2 cents in on dual rotor vs. single rotor. The ultimate easiest gyro to fly is a dual rotor with the flat stock blades and a small wing like the DB Sport. I had two of them and they fly great. The rotors just provide more balance than lift. I removed the wings and added aluminum/wood booms to hold new lifting blades. Now it's a real gyro but requires more skill to fly. The best and easy pure dual rotor to fly was a converted SIG Seniorita. I played with a helicopter rate gyro on the rudder and that provided a lot of stability. The FMA Co-Pilot does not work well on dual rotors. If the gain of the Co-Pilot is set high enough to be affective it wags the tail. For a single rotor, a converted SIG Senior Kadet is probably the overall best for performance and easy to fly. Add the FMA Co-Pilot and anybody can fly it.

For a beginner, if I were to compare the best dual vs. the best single overall, I would choose the single rotor for one reason. If the dual rotor has lifting blades without any wing, it must point directly into the wind on takeoff or it will flip over due to one rotor coming up to speed before the other. A single rotor will tolerate some cross wind. Once in the air, I would rate them equal

Another opinion.

Phil

Ok Dickeybird, now I see the reason for dual rotors, but again... I want to make a real autogiro!
I've seen many models named "autogiros" just because they have something spinning over a fixed wing (which provides all the lift), while others use a fixed rotor as a wing and use surface control. I agree that many gyrocraft started with this setup, but time and experience proved that they were most effective at high speeds, and thus abandoned soon, using DC instead. I find great to be under control even when you're below stall speed! But I have to agree also with you that they can be more difficult to see. I almost crashed once a brand new model because of this. And I also kept piloting the DC giro like a plane : ailerons work the same, rudder works the same BUT the engine adds both airspeed and altitude, while the pitch only adds more or less lift = more or less speed. Now imagine me pushing the right stick down like crazy to make it climb, till I remembered it had to be the gas stick!
By the way Phil, I don't know what the "FMA Co-Pilot" is and why "anybody can fly it". Is it one of those stabilizer sysems that keep your plane leveled within certain limits?
Hey, another good plane to work with has come to my mind, the TT MK II!
One more thing.... I planned to make the girocraft with some good theorical base apart from that knowledge experience brings. Do you know of any source over the internet where I can buy books about autogiros? I asked the only aircraft book shop here in Spain and I was lucky enough to find a small book about construction and flying

Hi guys,

Finally, I could draw some lines, according to these principles:

- Easy and fast construction. This is a foam-plywood hybrid, and it uses a fiber glass boom, and possibly depron or Coroplast tail surfaces.
- Good-looking, I'm tired of box-shaped gyros!
- Rotorspan, about 88cm. That's because blasa comes in 1m planks, and my DC giro uses just 0.54m of that plank, so this is the perfect excuse to make something with the many 40cm long blades I have lying around.
- Lenght, 72cm (28").
- Height, 17-18cm including rotor system (the fuselage itself is in the 14-16 range).
- Max width, 7cm (2.8").
- Hang angle, 5ΒΊ.
- Rotor mast angle, 10ΒΊ.
- DC control (5-6ΒΊ sideways, 8ΒΊ front-aft), throttle, maybe rudder.
- Tricile landing gear. This made me draw a small winglet, whose main purpose is just hoolding the landing gear.
- CG falls just before the winglet. I've drawn things so that most important forces are algined with the CG; however, servo and batt location may fool this a bit.
- Generous side area. Oh, before someone points it out, yes, I have to increase the blade clearance in the tail...
- Norvel 0.074 for power, HS-55 servos.
- This project's name is "As de Picas", the spanish for "Ace of Spades". I prefer to use my imagination for the drawing thing

A side view...


Please feel free to make any suggestions or comments!

Juan

That looks good. You are true that there is a need for nicer looking autogyros. You also right that your model needs more blade clearance. A boom strike might occur during hard landing. It would be interesting to see the dimensions on your drawing. Does it have elevator?

The tail boom has been moved lower, so that it is inline with engine thrust line. This gives about 1.6cm of clearance (measuring it always assuming the rotor is fully tilted back 8ΒΊ).
I'm thinking of lowering the winglet, as the main gear is 8cm long, and it should be 1.5 or 2mm thick piano wire (I fear it would bend too much), but I like where it is now.
Lizard, could you tell me which things would you like to know? I think it'll be easier this way!

Regards,

Juan

Hi again,

I've made some minor updates to the design.

Here's a view of it, along with some measurements (all units in mm)... If they're not clear enough I'll make several pics with higher detail.


My headaches now are caused by how could it be built, while being simple yet strong. So far, my ideas for the fuselage are the following:
- The main structure is similar to a profile. A plywood, lightened profile of the craft (the pic is the "fat" version ), with some balsa ribs (is this the right word?). This could be 2mm plywood, and 4,5mm thick balsa ribs.
- The tail boom has a 8mm diameter. To make it removable, I'd glue a 5cm long, 10mm diameter carbon tube to the rear side of this profile (you can see the hole at the end). This way, the boom would slip into this tube, and stay in place with 2xM2 screws.
- Now foam blocks would be glued between each rib, and then shaped. I think this could be quite straightforward to do with a hot wire; since you have the wood skeleton to use as a guide, you would only need to hand saw a few corners.
- Batts and servos have not been drawn... I'm not sure yet where should I make some space for the RC stuff, but I guess it could be done either in the "cockpit" (see doted line) or maybe between the main gear. I'm not sure how heavy this would all be or which way will I finally build this so, I'll get to this question later.
- After applying the foam, it could be possible to lay a very thin coat of fiberglass... or just some tape to make the foam last lnoger.



Now the pylon... Pretty straightforward as you see in the pic, quite more complex to explain...

- The pylon is mainly a CF tube. At a certain height, it has a plywood piece (it's like the base of the pylon) glue perendicullar to it; this is what fits into the fuselage, and could be secured either with a couple of bolts, some strong magnets, etc.
- There are also some side reiforcements to avoid the CF tube to tilt sideways.
- The CF tube has a slot under the plywood base. This slot fits in the pllywood profile, and should carry most stresses onto it.
- Servos are screw to a small balsa piece, which is glue to the CF tube.



I'm not much convinced with this kind of structure. It looks light because it's mostly a reinforced profile, but for some reason I don't fully enjoy it.
BTW, it seems my engine could get on time for January or so... (they must be making it with a nail file or something). I'm afraid it'll take a little longer than I wanted to build and try this thing.[]

Well, have fun![sm=RAINFRO.gif]

In re "Simple rotor blades", has anyone tried hot-wire cutting Blue foam?? then add a strip of CF ribbon to the bottom, from leading outboard edge to trailing inboard???
Per Phil's suggestion, I am going to make some of the SG airfoil planer blades, but in the meantime, I'll test the blue foam/CF idea..
Robobart