Item 0475
OTHER:
Helicopter - Outside - Intermeshing - DeGraw - HummingbirdHomebuilt Helicopter by Mr. Dick DeGraw in the mid 80's
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Summary of Remarks from Conversations with Mr. DeGraw about the Hummingbird:
February 5, 1999
His synchropter;
2 feet between rotors
He has 600 hours of flying on it.
He has not flown it for 2 years.
Blades are Rotorhawk asymmetrical.
Rotor RPM is 425.
Disk diameter is 25'-6"
Blade chord is 8"
On warm summer day with engines producing 110 to 115 hp at 3500 rpm lift was 1700#.
The blades between the 2 rotors get along very. In other words he did not experience any problems from blades passing through the downwash of another blade.
His blades rotate forward on the inside. He said that this has the advantage of keeping the blades apart.
His V is 26 degrees.
He could not comment too much on lead-lag. His was built before the K-Max with its delta3 by flap hinge geometry.
He said that the helicopter needs a lot of tail surface.
He was very happy with its performance.
It was the first of 6 projects over the past 15 years.
I mentioned that the horsepower I am hoping for is 28 * 2 and he said that is plenty.
December 21, 1999
Phoned and spoke with Dick DeGraw.
I told him about my web site.
Said that I was following in his footstep but did not want to step on his toes.
He said he would look at web site and get back to me if he saw any glaring problems.
Additional Information:
Locations of specific Information:
This Web Site:
Use search engine, located on initial page, to find all locations in this web site.
Other Web Sites:
http://delta.wtr.ru/files/Hummingbird.pdf
Miscellaneous Information:
Note
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Last Revised: February 21, 2008
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