Hello all,
I've done several scratch builds, mostly "bashed" versions of proven designs. I've acquired a Saito FA-30 Golden Knight four stroke that runs quite well. Thought I'd like to build a standoff scale Dalotel to put it in. I like to fly "Sunday aerobatics", the overall design is attractive, and no need to vacuform the canopy.

I've been told by the more experienced at our club that the FA-30 would be roughly equal to a 2-stoke 25. Also that E-Flite motors of 25 size are roughly equal to a .25 2-stroke. OK so far I guess.
Trying to "size" the build, I researched 25 size electrics and found that wing area for "sunday aerobats" is in the 480-490 sq in range with about a 50-53 inch wingspan.

I've located some 3-views and even a set of barely legible plans for a ? .46 ? size plane. My attempt to resize for the FA-30 result in a WS of 52" and area of 484 sq in. I've always built very light, both kits and scratch, but won't even attempt at a guess for overall weight.

So the question is, does this size seem reasonable for that engine?

TIA for any suggestions.

G42

I've two Saito .30 engines with both on light weight models having generous wing area. The first is a Sig LT-25 that called for a .25 two stroke. The other is a Das Box Fly Bipe that called for a .20 two stroke. Both have low wing loading of around 12-14 oz/ft and both fly well with the four stroke .30 with neither being fast but taking advantage of the 4 stroke torque and flying on their wings rather than requiring speed.

The LT-25 has 724 inches and the Das Box Fly Bipe having 620.

As can be appreciated, both the examples have considerable drag but are suited to fly slow because of generous lift. A friend had a Saito .30 in a Newbee and it flew well, though it was faster. The Newbee is 40" span at 3-3.5 lbs.

In general, I guess I'm saying that a saito .30 is a good trade for a 2 stroke .20-.25 but preferably that the extra weight is shouldered by adequate wing.

Thanks for the detailed reply AA5BY. From your comments I would guess that I'm in the right ballpark for the type of flying I prefer.....as long as I keep it light! Perhaps just a wee bit more wing.

David Boddington designed a 47 inch 1 /7 th scale Dalotel for RC Scale Aircraft Quarterly 1986 Summer issue. This was for a 30/40 size engine Plan is available from http://www.myhobbystore.co.uk/produc.../rc1515dalotel in England. Used foam wing. Cowl is available too. Magazine also had a profile of the full size and a 3 view if I remember correctly. Note its a Dalotel Viking. I built this model from the plan but it's still unflown - I may convert it to electric.

David Boddington also scaled this up to 74 inch for a 1.20 engine at a later date, plan& cowl are also still available from MyHobbySores.co.uk