Nick,
Your comments about ultralight helicopter design are very,very interesting. I hope to hear more.
It's obvious to all that very few, if any, ultralight helicopters have been a success. Often unproven designs are sold to enthusiastic non-aviators that eventually discover they made a big mistake, if they survive.
My assessment of current ultralight designs is that they try to extract more power than the available engines were designed to deliver on a continuous basis. Until affordable high power to weight ratio engines are available wouldn't it make sense to design the helicopter to fly with less power?
Nick wrote "Most successful solutions use more engine
power, lower radius and higher disk loading because then the structural
problems are more easily met."
When the engine fails with a low time sport pilot at the controls, does your higher disc loading recomendation still apply?
I am still trying to comprehend your argument that higher power loading is an advantage. It seems to me that an airframe that can lift 25 lb/hp could include more structure and other safety features than an airframe that lifts 7 lb/hp.
I own a G109 motorglider that can lift 1830 lb with 80hp (23 lb/hp). The large span makes the aircraft heavier, but overall it is more efficient than other airplanes at slow speed and can be flown quietly at low power. It seems to me that a large helicopter rotor would be better for less skilled pilots.
Nick, maybe your point was that designing to meet the 254 lb ultralight weight limit is extremely difficult. I agree.
If a safe sport copter needs to weigh more than 254lb thats fine with me, it can go into the experimental category.
Someone said (I think it was Robborider) that my design goals were contradictory, he may be right.
Keep sending facts and opinions, only the laws of physics can slow my enthusiasm.
Last edited by slowrotor; 8th Aug 2003 at 00:38.