"No, no, I will fly the way I fly, and you will fly the way you fly.
We will both enter LPP times in Jeff Hood's postal, if you agree."
I accept your challenge.
I was planning on doing further tests with the Dandiflyer to get the most
time I can get, then apply my motor design method to the AMA Cub, EZ Pennyplane,
Comet sheet Curtiss Robin and Peck Peanut Gipsy Moth. I wasn't planning on
entering any contests. Most of these use plastic props and I wasn't
planning on modifying them. I will make a LPP my next project. I expect to use a
pretty conventional, fixed helical prop. I will enter my best test flight
times in Jeff's Postal.
I have no idea what size rubber I will be using, I have not even seen the
specification for LPP. My method of sizing motors requires a level flight test
and an altitude flight test. If I am not using a standard plastic prop, I
will also need to test several props. Only then will I be able to select a
motor cross section and length. At that point I will be able to write the
equations for the optimum cross section and length of motor and duration for each
ceiling height.
I fly in the same Gym as Tim Chang. I see the ceiling he has in his postal
entries is 23 feet.
Another thing to consider is the specific energy of the rubber. Differences
here could make all the difference. For contest purposes, you get what you
pay for. For purposes of comparing methods, that must be taken into account.
"...and used on a non flaring prop, which obviously should be more
efficient than a highly flaring prop."
I never said not to use a flaring, or anti-flaring prop. I said the purpose
of a twisting prop should not be to control RPM, but to control efficiency.
I expect I will use a fixed blade prop of fairly conventional design (am I
actually capable of building a prop without several points of innovation? I
doubt it.), but if I decide I can get better efficiency with a twisting prop,
I will do so. I will not accept any limitations that are not equally
applicable to all entering the contest.
"Some of us don't speak "Dandiflyer" whatever that is."
The Dandiflyer is a 16" beginner's ROG designed by Erv Rodemsky, kitted by
Lee Kirakofe (Lee's Hobbies) and sold by Tim Goldstein. There is a small
perspective drawing on Tim's site. You all know where that is. We use the
Dandiflyer as the second model after the AMA Cub in out kids classes.
Looking in my model box for a good LPP kit, or a good plan and some light
balsa,
Gary Hinze
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Received on Thu Mar 22 2007 - 20:21:37 CET