Funny as it may sound i bought a biplane from a hobby shop 22 years ago.
i build the kit but never got an engine or radio equipment for this as i had to move etc .It was sold to me as a bistormer but that is all i can remember.

the plane:
weight is 8pd 4 oz without tank, motor,radio gear.
wing top 72"x12"
bottom 70"x12"
all balsa covered with silk & dope.

i would like to know which engine would be the size to go? the old big 61 glow fit like a glove in the cowling but i am afraid it might be to little power.i see the new os fx 91 is the same size and weight as the 61 and the 120 ax is about the same size as the 91 but 4 oz heavier .which` one will be the one to choose??

can anybody be so kind as to advise me on this.

thanks

riaan

My old Tequila was about that size. I flew it with a .90 2-stroke, but just barely. I'd think you'd be better off with at least a 1.08, or one of the big Super Tigers.

If it was designed back then, it might not have been designed to blaze around the sky, whipping through fast snap rolls, and cranking along at much more than a leisurely pace. Take a long hard look at the structure and keep that in mind when you decide on the engine for it.

Nowadays the .46 size engines pull like the old 60's did. etc etc....

got a picture of the thing? Identifying it might be the safest way to discover what engine would suit it best.

That's a little less than 12 sq. feet of wing area; at ten pounds that comes out to less than 15 oz/sq. feet wing loading, Even if you stick enough stuff in it to get the weight to 12 or 13 pounds, the loading will still make this plane a floater. I'd say a .90 - 1.00 4-stroke would be a great engine. Turn a nice big prop with 5-6 pitch, it should fly like it was intended to. It still would be nice to know what it is.

At over 8 pounds, without engine, I’d go with a .91.

The 1.20 is about ¼” wider, longer, and taller than the .61 or .91 so it could present mounting issues depending on the design of the plane.

You might consider the MVVS .91, same size and weight as the OS.61. This link is to a seller in the UK:
http://www.justengines.unseen.org/mvvs.htm
They are made on the Czech Republic and, like many European engines, are designed for fuel with little or no nitro. If fuel with nitro is difficult to get in Africa this might be important to you.

Please post a pic if you can. But I would tend to say that a 91 4 stroke will fly it quite well. A YS 110, or OS or Saito 120 would be even better.

I wouldn't insult that airframe with a 2-stroke.

A 4-stroke might be nice these days, but I highly doubt the model's designer had anything but a 2-stroke in mind.