Subject: 2 place VTOL / Ducted Fan
From: rotaryeng
Date: 4/6/2014, 6:13 PM
To: AAA-rotaryeng



Hi Paul,

Thanks, I didn’t expect an answer so quickly. Aren’t you wrapping it up at SUN & FUN today?..

I am interested in building an up-dated 1/2 scale flying model, or a proof of concept single place engineering test vehicle.

Possibly an ultralight or another aircraft that could prove out some concepts and configurations.

I expect that you have a lot of thoughts on which configurations are really efficient. Can we advance the design or designs ?.

In 2001 Roy Lopresti (my former partner) in LOGO, introduced me to one of the Navy test pilots that test flew the VTOL’s

In the 50’s. Roy was the Air Force Test engineer at Wright field at the time those tests took place. He really shared some

wonderful and interesting insights into flying a VTOL.

After 12 yrs. off the project. I’m ready to dust it back off and revalidate the concepts and designs

What would you like to see done. And where are you located.

The video’s and patent references are 10 yrs. old but they demo principals that did work.

Larry

That is all well and good for hover but ducts are bad for high speed forward motion. The drag of the duct far outweighs the advantages.
Perry Mick tried for years and finally gave up and put a gear box and prop on it and went 30 or 40 MPH faster on the same fuel burn.

Paul Lamar

Yes, There is a speed penalty to pay. I should have better defined the prime considerations of the design concept.
It must be a VSOL or a ESTOL as defined by NASA. My other design goals were and still are, as follows.

Produce a  SIMPLE, SAFE, AFFORDABLE,  LSA 1320 lbs. gross vehicle that preforms most of the functions of a
HELICOPTER and a FIXED WING 2 place aircraft, trying as hard as possible to use only the primary elements
of a Piper Cub. A single direct drive prop rotor, (might require a planetary reduction). No cyclic blades,  No complex
transmissions, No major rotating structures, No tail rotor, No exposed blades ,(duct is required) to allow harmlessly
bumping into trees, structures, and to protect people, as well as descending into and thru urban areas. as well as an
increase in static thrust of up to 30%. About the same % of speed loss on the top end. Since we need more HP to
hover (or near hover), some of that excess HP helps overcome the extra drag. All controls are push-rod or cable.

The above requirements would produce the all elusive Jetsons flying car, or NASA PAV (personal air vehicle).

Since, the 1/4 scale flights adhered to all of the above. Without having to use contra rotating props.(less complex
and weight) I wanted to further improve the design and increase the size of the test vehicles, using as many in-
expensive off the shelf components as possible. The model had both duct and standard flight controls and flew well
with either, it also flew well with out the rudder. A V-wing Delta shape might also work but at a lower AOA.

I am quite familiar with Dr. Paul Moller's efforts to have the perfect vehicle with the perfect Rotron engines. After
40 yrs. and $400 million dollars, I wish him every success in his efforts. I don't have the time or the money.

NOTE: Roy LoPresti did design a military version of this concept for us that used the same P&W Canada engine
out of the V-22 with a smaller 7f.t dia. ducted prop-rotor, flat rated to around 1550 hp. that had a top speed of 500
mph..  Costs would have exceeded $5 to $10 mil. plus engine and prop. which is a bargain for the military.

That’s the short version of the civilian concept of the design. I may be too simplistic in trying to keep it simple.

Your comments please,

Larry


What HP do you need?
What engine weight FWF?

Paul Lamar


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