A popular (and safe) design is the GyroBee by Ralph Taggart. The prototype was a true 103 ultralight with a Rotax 447 which, IIRC, clocks in at ~39 HP. I'm curious about the 200 lb. empty weight. It's very difficult to build under the 254 lb. legal limit with conventional materials and components. How was the 200 lbs. estimated?430lb I indicated is total weight including fuel and payload. Empty weight is about 200lb. I am just asking the power required for such a gyroplane.
If you have a max weight budget value in mind for the powerplant choice, you could state that, and people could tell you what powerplant installed weights for various combinations they know about from their experience.430lb I indicated is total weight including fuel and payload. Empty weight is about 200lb. I am just asking the power required for such a gyroplane.
Interesting...It depends on the diameter of the rotor and the diameter of the propeller.
With a 23 'x 7 "rotor and a 63" diameter propeller, more than 35 hp are required for a total weight of 430 lbs
No simple formulas, Xavier. Just my many simulations with the best ratio power/weight of engine, the best ratio load/ weight of airframe and the best ratio weight / diameter of rotor.
I have never obtained a result lower than 35 hp to takeoff with a nose-up rotor of 18 degrees.
This angle gives a takeoff in a reasonably short distance. Takeoff with less angle is obviously possible but does not seem to me to be practical enough.
Here, I'm talking about the traditional layout, but of course more complex and expensive layouts could be better (bi-rotors side by side for example)
No, I don't. It's Jean Claude who has designed his spreadsheet...To answer the question above about my ultralight. I was hoping an engine of 35hp to 40hp for a basic flying machine. I want to build it as light as possible. Other than the rotor head and the engine, the rest will be built with CF (I do have composite experience). So it is not inconceivable for it to be about 200lb.
Do you have a spreadsheet to do the power estimate?
I thought so. 40+ hp is better. It all comes from the huge drag of the rotor. Does lamina blades help?Minimum required power to make it fly decently on warm days at your all-up weight might be a bigger practical concern than having too much power and busting the speed limit (as you asked in the first post). The 35hp mentioned by Jean Claude is a number I have seen mentioned many times as a floor value for a practical ultralight.
That's why I was thinking if a very light gyro can be powered by an engine like the Thor 250. Power is a bit low, but the weight can be reduced so much.The Pollini Thor 250 has been used successfully on lightweight gyros. still low power but the engine is very light.