Autogyro Rotor Tip Rockets
An autogyro - also called gyroplane - looks very much like a helicopter, but the rotor is not driven. It rotates freely. The autogyro is instead driven forward with the help of a propeller, like an airplane.
An autogyro needs to roll faster and faster on the field before the rotor spins fast enough in the wind for the autogyro to lift off. 100 meters or so of runway is needed for take-off. Many autogyros have a link shaft from the propeller engine and a cogwheel drive so the rotor can be pre-rotated before take-off. The take-off distance required is then shorter.
If the rotor is pre-rotated with tip rockets it can take-off vertically like a helicopter! So far, tip rockets have been tested on very few autogyros. The best known project is Fairey Rotodyne. Fairey Rotodyne could carry about 50 passangers and the first flight took place in 1957. Vertical helicopter style take-offs and landings were made, using the tip rockets. Rotodyne was cruising at 310 km/h (!) with help of the thrust from propellers and with the rotor spinning free. As the tip rockets do not give a torque force that want to twist the autogyro in the opposite direction, there was no need of a tail rotor as is the case for a helicopter. Despite the project was a tremendous technical success it was still finally cancelled, because the noise was said to be too high when starting and landing in heavily populated city centers.
A movie presentation of the Fairey Rotodyne project
PEROXIDE PROPULSION ROTOR TIP ROCKET PROJECT
DEVELOPMENT Year 2003 -2004
I presented the idea to install and test hydrogen peroxide tip rockets on an autogyro, at the Swedish Rotorcraft Flyingclub's annual meeting at Gävle-Sandvikens Airport on May 30, 2003. The members found it very interesting. In September 2003 we started the project. The first prototype system was installed on a gyro glider during the summer of 2004.
The system was a great success! We COULD really make vertical take offs!
When pulling the glider forward, right after it started to lift we could make very nice and stable 0-roll take-offs, as shown on this movie:
DEVELOPMENT 2005 -2008
This first system was damaged and had to be scrapped, later in the summer of 2004, after a demonstration when the rotor struck the long grass at take-off and the glider fell over on the side. Goodbye, rotor!
We continued the development of rotor tip rocket systems though. The work is reported in the application archive found on the right side of this page.
NEW ROTOR TIP ROCKET SYSTEM (June 2010)
We have built a new rotor tip rocket system.
This time we have chosen to have an an atmospheric peroxide tank (no pressure!) and a fuel pump, instead of a pressurized tank.
Peroxide tank and pump (driven with a battery screw driver!)
The tip rockets are embedded in the rotor blades. Only the nozzles are sticking out outside the blade tips.
The rockets have double parallel catalyst chambers to reduce pressure drop.
Rocket drawing
Rockets before installation
Bolting the rockets to the blades
Covering the rockets with a Al plate skin
Rocket installation ready!
The design of the rotor head with peroxide transfer lines can be seen on the below drawing
Rotor head. Standard type and with fuel transfer lines.
Testing of the Tip Rockets on a Powered (!) Gyroplane
We are now testing the the tip rockets on a propeller powered gyrocopter for the first time! Up to now all test have been on a glider gyroplane.
It is a Ken BrockII gyrocopter owned by Clark Cogan, Franklin, Indiana. Thank you for testing the rockets, Clark!
Clark Cogan (Gyro Owner and Test Pilot), Gary Goldsberry (well known PRA President during many years) and myself in front of Clarks KB II.
The propeller motor is a MacCullough. Unfortunatelly Clark has a problem with his "Mac" at this time. Of some reason it is developing far less than the 70 hp it is rated for, so it will be difficult to take off until the motor is running at full power.
Clark is spinning up the rotor with H2O2 for the first time. June 13, 2010.
Clark is now drilling the rockets to a bigger diameter to be able to pre-rotate the rotor up to around 300 rpm (=lift-off speed!). He is also doing other fine tuning jobs and is upgrading his MAC. We will be back as soon as we can show a nice take-off!
This article was updated on June 21st, 2010