A while back I posted a question about four stroke motors, as I was planning
to scratch build one. I'd no intention of flying the thing (see link)
http://www.youtube.com/watch?v=7X2pe7BrtT8
but simply to see if I could actually build something that runs. Lots of
learning along the way, but with new confidence started to plan the build
of a .60(ish) v-twin four stroke. The design is supposed to be able swing
a 12x6 prop at 8000 rpm, so not a screamer, but what sort of model?
Here is one of these engines I found on Youtube:
http://www.youtube.com/watch?v=OLg9hga-1IA
All I need now is workshop time (the last took nearly two years!), hopefully
get this done for next summer.
I'm thinking of something like an Eindekker or DVIII as a sport scale? I
haven't flown RC in many years, and would intend to find a local seasoned
flyer so model choice needn't be restricted by flying skill (I prefer
building...)
So you seasoned flyers what would you do with a .60 v-twin at the lower end
of the power output range?
TIA
Steve
Martin X. Moleski, SJ - 23 Aug 2009 15:00 GMT
> ... I'm thinking of something like an Eindekker or DVIII as a sport scale? ...
With low-power engines, you want to think "floater." Low wing loading,
high-aspect ratio.
The Eindecker probably has less drag than the D VIII--a lot less.
I've seen them putt-putt around our field with relatively little
power applied.
Alternatively, treat your engine as if it were a .40 two-stroke
and build that size biplane for it. WW I models are reported to
be good for heavy engines because they often need a lot of
ballast in the nose to get the CG right.
Marty

Signature
Big-8 newsgroups: humanities.*, misc.*, news.*, rec.*, sci.*, soc.*, talk.*
See http://www.big-8.org for info on how to add or remove newsgroups.
Tim Wescott - 24 Aug 2009 16:50 GMT
> A while back I posted a question about four stroke motors, as I was
> planning to scratch build one. I'd no intention of flying the thing
[quoted text clipped - 26 lines]
>
> Steve
I'd be inclined toward a 1/6 scale Cub* or similar sized Pietenpol. If
you don't want to spend the extra time on scale, consider an
appropriately sized Telemaster.
As Marty said, think "floater". I would add that you probably want to
think "clean"; putting all the trimmings on a biplane adds a _lot_ of
drag.
* A 1/6 scale Cub has a 6-foot wingspan and if built light will fly
adequately on a 0.25 two-stroke. Your 'V' would be seriously not scale,
but the thing would be glorious in a slow fly-by.

Signature
www.wescottdesign.com
Steve - 27 Aug 2009 07:36 GMT
>> A while back I posted a question about four stroke motors, as I was
>> planning to scratch build one. I'd no intention of flying the thing
[quoted text clipped - 38 lines]
> adequately on a 0.25 two-stroke. Your 'V' would be seriously not scale,
> but the thing would be glorious in a slow fly-by.
Thanks guys. I had thought Cub, but hadn't a clue how to relate the
engine power to size. So I'll put that into the planning.
I have successfully built an all built up balsa 6 foot glider, so a Cub
from a plan shouldn't be beyond me.
Steve