A-sized low-wing sunday flier
 

Hi all,

I've been drooling over this wee little .20 sized OS 4-stroke, but I've no idea what plane I would/could/should put it in... If I can find a plane I'd like to build for it, then I might buy the little guy and put it on the shelf while I build my trainer (gotta plan ahead!)

I'm assuming that an airplane designed for a .10-.15 2-stroke would work well with a .20 4-stroke? What I've got in mind is something low-winged, but still relatively tame... something that might make a good first low-wing, or good second plane. Some moderate aerobatic capabilities would be nice, but it needn't be cutting edge.

I saw the House of Balsa .10 Skywalker, but i'm afraid the .20 4-stroke might be a bit on the large side.

Any suggestions?

thanks!

-Rick

A-sized low-wing sunday flier
 

It great place to start is the Randy Randolph designs - very easy to build and actually decently looking models.

Off the top of my head I can think of the Dime (high wing though). You can find these online at the AMA site (www.modelaircraft.org) under the digital archives. Do a search on "Randy Randolph" and you will find probably 4-5 designs that would be perfect. Added bonus = relatively cheap plans from Model Aviation.

Brian (Av8rsodt)

A-sized low-wing sunday flier
 

I have a WM Aircombat Arf with an FP20 up front that flies very well. No bad habits and will not stall - just mushes straight forward. WS is 48" and takes off easily fro grass at half throttle. You might give one a try.
2alpha

Going to purchase....
 

one of the world models kits. I am very excited about the possibilities.

A-sized low-wing sunday flier
 

Ive got one of these engines that I've never run yet. It's truly a real cutie.

One of the English mags had a couple of designs for them a few years back. The big thing is to keep the model light and larger so that it flies on the wing and not the prop. Old timer cabin or shoulder wing designs in the 50 to 60 inch size range would be perfect trainers but may be a little lazy for you depending on what you want.

For something moderatley aerobatic I agree that many of Randy Randolph's designs would be just right. Pick the wood to keep them light and consider shortening the nose by about 1/2 inch to compensate for the greater weight compared to the usual 15 sized 2 strokes that he liked to use.

In any event don't plan on going over about 2 1/2 lbs if you want to have any sort of climb ability. 2 lbs would be lovely but it'll take some serious wood selection and the right design to do that.

I'd suggest a 3D type construction but that would be so far out of the character for this engine that it would be silly.

I'm planning on using mine in something WW1'ish with about 500 to 550 sq inches and built up like an old timer stick and tissue model. There's been a lot of Speed 400 electric biplanes offered in the English mags in the past couple of years. They all have around a 36 inch span and run through a photocopier to enlarge them up to about a 44 inch span would make them perfect for the FS20. Just resist the urge to beef them up. Stick with the wood sizes of the smaller version with just enough adaptation around the firewall for the engine and it would build up to about that magic 2 or 2 1/4 lb mark with small radio gear.

A-sized low-wing sunday flier
 

I built the HOB spacewalker and I think you may be ok with the OS .20. I had a Norvel AME .15 in mine and it was pleanty fast. In fact, I'm not the best builder and don't remember the weight but I had pleanty of power.

ZB

A-sized low-wing sunday flier
 

Maybe ace super-pacer would fit the bill it's designed for a 19-25 engine. the size and shape sound about what you are looking for.


Randy (Digger) Birt

A-sized low-wing sunday flier
 

Hey Digger and 2alpha. The 20 sized 4 stroke doesn't have anywhere near the power of the 19 2 strokes. In fact it probably only really has the power of an OS 10FP. But of course it swings a larger prop at lower rpms. But thanks to all that any sort of pattern type model is probably not the best choice IMHO.

Even the later 26 4c has much more power for it's displacement than the earlier 20 4c.