Home built collective pitch autogyro

[Bimbo]

Hi all,

I wasn't sure where to put a thread like this, but here goes

(more pics below)


I've been intruiged by autogyros for a while, and I've bought and built the Cierva C30 from HK. It has a 'regular' rudder (like a plane has), and aileron and elevator are controlled by tilting the entire rotor head assembly. I must admit I never really got it to fly though... Now HK has the new Durafly Auto-G(2), I just ordered it, hopefully it'll come soon. It only has aileron on the rotor head, elevator is controlled by a horizontal stabilizer like a plane has.

So, I used a 450 helicopter frame, and mounted a motor for a propellor in front. I used a 4-blade rotor head to have enough blades for lift. Removed the tail case and glued a balsa tail boom in (and used some parts from the Cierva that never flyed...). I haven't added rudder control yet.

As you can see there is still a main gear and autorotation tail drive gear, this is to keep the main shaft in place. Later on I'd like to add a pre-rotator to it, using the motor mount from the 450.

Installing the motor mount for the propeller was easier than I thought. I used some balsa wood, reinforced it with fibreglass (FG) and used medium CA to glue it in place. Rock solid! Actually didn't expect that to be so strong but it's good! I use 2 long screws to the motor, which also allows to change the downward angle of the prop a little if needed.

The landing gear is kind of interesting, I used the wheels from the Cierva, and an old 450 tail boom which will simply skid on the ground when landed. I intend to take off by hand-launching.

Electronic setup: I do not use a gyro or FBL system. I'm hoping 4 blades will give enough inertia for stability, and I'm afraid the FBL unit would work against me, since the swash is in semi-heading-hold mode (at least in a BeastX). So cyclic mixing is done in the radio. Now here's the key in pitch- and throttle curves, as obviously now the throttle works on the prop, and not the main blades:

Throttle hold: throttle zero, full collective pitch control (+12 to -12 deg). Can also be used to land like you would land a regular heli in throttle hold.
Normal mode: fixed pitch (flat pitch curve) around -3 deg (what 'normal' autogyros have), throttle curve from 0-100%
Idle-1: flat 70% throttle, full CP control
Idle-2: flat 100% throttle, full CP control

I have two more modes available on my TX, but this will do for now.

Last sunday I took it to the field with 325mm asymmetrical main blades, and there was strong wind. It was amazing how much speed the rotor gained! And I could feel the lift in my hand. Unfortunately, one of the blades hit the vertical stabilizer so I didn't get to try to see if it would actually fly... Hopefully next weekend









This last pic is after the rotor whacked the vertical stabilizer...

Comments/ideas/support welcome

[BladeScraper]