Re: Power for R/C models

Douglas R. Jones (
Tue, 06 Jun 1995 12:37:48 -0500

>Perhaps you might be kind enough to also post to the list information about
your choice of motive power for each and how the model performed.
Inexperienced WW1 modellers like myself would be interested to know:
>1. Choice of engine (electric motor)
>2. Was the power available, adequate for safe flight, comfortable without
too much risk of non-scale speeds or too much for the model.
>3. Any other problems.

Be happy to!

>Questions like these are always a problem for new starters before investing
in a new project. The listed engine sizes that come with published plans are
not always reliable because you are not aware of the preferences of the
designer and whether or not the publisher got it right anyway. I have
noticed a number of anomolies (spelling?) when looking at the catalogues of
various plans services.

This is a problem when dealing with plans and kits. And I have never been
able to come up with a decent means of resolving this. Certainly any
published reviews can help. Or do as you have done and solicit public opinion!

>PS. I have sent a similar letter to Guy Fawcett. Perhaps there are others
who could contribute.

Guy is an excellent resource. Bob Spear ( would be
another. I am not sure if he is still on this list or not. Another would be
Jeff Friedrichs ( might be another.

As with any aircraft the quality of flight is directly dependent on the wing
loading and flying style. Certainly you can put adequate power on a brick
and make it fly. But it won't be scale. My Bristol falls into this catagory.
Currently I am flying 2 WWI models. They are:

Flair 1/6th Sopwith Pup, 60" WS, 7.5 lbs, 14 oz wing loading, ancient OS 61FS
Balsa USA 1/6th Bristol M-1C, ~48" WS, 7.5 lbs, 23+ oz wing loading, Saito 65

The Pup is a dream to fly. Th wind makes her a bit touchy sometimes. I am
comfortable up to 15 mph steady and slightly less if it is gusty. The 61
pulls her along just fine at 1/2 throttle. Too fast almost. I am using a
12x7 now and plan on trying a 13x6 as the summer wears on. I throttle up
some for aerobatics. In the hands of a good pilot (I don't qualify) she will
do several consecutive barrel rolls. She can be flown very scale with no
real effort. (Can you tell I REALLY like this plane)

The Bristol is a pig. The 65 provides adequate power to fly her at full
throttle. She will do some aerobatics. You have to "mind the store" as she
has a nasty tendency to snap out of a loop. I have some balance issue I
think still. So as I get CG straightened out she may get a bit nicer to fly.
At least I hope, since the wing loading tells me she will never be anything
but a crash waiting to happen!

The 17 that's one the board will get a Surpass 48. I hope to keep her to
about 5 - 5.5 lbs flying weight. Haven't run the numbers on wing loading
yet. I hope no more than 18 or so. I have seen this same kit, built stock,
(mine is bashed) fly on a Surpass 40. Very scale. Nice combo!

I have a Sport Scale SE5a and Dr1, both 1/6th, that I will put Saito 50's in
if I ever get them built!

The bottom line is build them *LIGHT*! Light does not necessarily mean weak,
either. Watch out for plans/kits as they are often overbuilt. Especially if
they are done here in the US. The plans from Europe, and specifically
England, do about the best job of maximizing size with minimizing weight.
This not only gives you a model that will be a gentle flyer but allows you
to keep the costs down for servos and engines etc.

Hope this helps!

'I am a traveler of | Douglas R. Jones
both Time and Space' | IEX Corporation
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