Ken Welter wrote:

  The coot and any pylon pusher plane has a very narrow CG range,
the wing has a wider margin that it can be operated in but with
this type of plane in the event of a engine failure the prop drag
will pull the nose up and with the engine mounted high it will
shift the weight aft when the nose comes up. For this reason you
need to operate on the forward edge of the CG window of the wings
specs. To complicate this the passenger weight is forward and
changes the CG drastically and for this I have a 2.5 gallon fuel
tank in the nose and a one gallon tank in the tail cone to shift
the weight and keep the CG dead on 25 percent of the cord. Jim did
not build his coot he just installed the rotary on a coot that he
bought and there was two seven gallon tanks in the forward floor
boards that I told him needed to be full to fly solo to keep it in
CG and he did not believe me but I don't know if they were full at
the time. The lake also has this problem and they have weights

that

they slide in and out of compartments in the front and rear.
  Ken Welter

Very interesting Ken. Awhile ago I thought a configuration like

this might

lower the position of the CG.  Given what you are saying above a

pitch up

would not move the CG aft as it does now with a high mounted

engine. Since

you are already using a belt drive all you would need is a longer

belt.

BTW how is Don Moncrieff coming along?

Paul Lamar

   From Ken Welter
    When I went from the Ross gearbox to the cog belt redrive it

made

a big difference in aft CG shifting, the redrive that I am now
running has a 11 inch offset and I can make a redrive with up to a

18

inch offset but to go any farther you would have to have a jack

shaft

and run two belts. I did consider running a longer belt but it
brought up a host of other problems so I felt that the 11 inch

offset

was the best compromise. As for Don Moncrieff is he still on the

list

as I do not remember hearing the name in the coot world and would
like to get in contact with him.
  Ken

Yes he is still listed but I have not heard from him for a long time.

Paul Lamar

Don Moncrieff wrote:

Hi Paul and Ken,  I'm still plugging away at trying to get my 13B to run
well. I've not made much progress through the winter. Hopefully Spring
will give me more time suitable for outdoor testing. Thanks for your
interest. Don Moncrieff-- 

What seems to be the problem Don. Perhaps we can help.

Paul Lamar
 
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