Are you keeping it CL, or going to RC?
Without seeing how it's designed it's hard to say, but I suspect you'll
do more work modifying the design for ailerons and rudder (if you're
converting to RC) than you will putting an electric motor in there.
There's a ton of guidance out there for sizing the electric motor -- get
back to us if you can't figure out what to use (hint: tell us what the
original motor was, and the size of the plane). Most of the older
planes used beam motor mounts, and most of the current electric motors
are firewall mounted, so you'll have to redesign the nose. How
difficult this is will depend on how central those motor bearers are the
If you're keeping it CL check the forum on Stunthanger.com -- there's
some nifty timers for running electrics out there these days. I don't
know if anyone's done a throttle yet for an electric from a 3-wire
system, but I sure hope it's out there!
On Tue, 27 Apr 2010 20:08:26 -0400, ted_w email@example.com (Ted W Lee) wrote in
A fellow in our club has had surprising success (surprising to
me anyway) in doing conversions like this.
I imagine you might need to be careful about the CG.
With some scale models, it helps to enlarge the vertical
fin to get a better-flying model. I don't think that
would be as important an issue for the CL models as it
is for RC.
Check the Stunthanger group -- I want to see the answers!
A .19 to .49 engine from 1946 may make sense in a 31 inch wingspan
Stinson, but today you wouldn't want to put in more than a .21, and a
hot .09 would probably work if you built light.
An e-flight 15 would probably work, but I don't know where to go for the
I got a reply today to my 1st post on the Stunthanger "AMP'ed" forum
Tim. The reply concerned mainly info on which elec. motor system to use.
I hope to get future info on changes to the fuse on installing elec.
You suggested that I post replys here. I see that you are a member of
Stunthanger. Would you want read them there (Stunthanger), or have me
post them here. BTW, the man who answered my post lives in Marshall,Mi.
which is about 30 miles from where I live in Spring Arbor, Mi.
If you would want to make a copy of my Stinson plan , I could mail it to
you. The plan is one sheet 31"X42".
Did I? I'll see your thread on Stunthanger -- I check it pretty often.
How to modify things to accept the electric always depends heavily on
how the fuselage is built, so it varies widely.
Basically, though, you need a firewall that's much farther forward than
the original or you need to build a box to mount the motor onto that
puts the propeller where it needs to be. Then you need a home for the
batteries, preferably one that gives you a convenient and good looking
hatch for removal, because you really want to charge LiPo batteries
outside of the airplane.
The Reliant has a radial engine, which means a short nose moment, which
complicates things even further as you (probably) want the battery as
far forward as possible. You may even want to make the cowl to be
easily removable and to be the hatch, and you may even need to have the
batteries extend forward into the cowl area -- this all depends on how
the plane is built, of course.