E-4 Electric (oz15473)

About this Plan

E-4 Electric. Radio control sport aerobatic model, for electric power with Speed 400 motor. Wingspan 37.5 in.

Quote: "A neat 38 in span, light sport aerobatic model for S400 motors by Peter Holland.

Those little Speed 400 motors are so popular now that smaller, cheaper and more sprightly models are becoming increasingly interest-ing. Peter has always been one to 'add lightness', and the weight saving features of his latest electric design also add action. See for yourself with our FREE plan this month.

This model is a far cry from the rather more kinetic flight style of ray earlier 'Flapdoodle'. which has a 540 motor and eight Sub C cells. The wing loading is much higher than this little E-4- Electric, and I learned that bags of speed helped the more complicated series of manoeuvres.

However speed and weight combine to add wear and tear to an airframe, particularly on less resilient landing grounds. I know, over twenty years ago I test flew the prototype of that worthy machine on Chobhem Common, and although it now has a new, more streamlined fuselage. I feel like re-naming it 'Apache!'

So now, R/C gear is lighter, seven or even 6 cells of 600mA, AE type are a far cry from the Sub C eight pack, and the motor is about half that of a 540. Use a BEC switcher instead of a servo and out goes the 225mA R/C supply too.

With all that payload change, I cut down on wing area of this completely new, low wing design, so that I could restore some kinetics via a fairly good airspeed. All of this results in a responsive model that is small enough to bounce if you are late on the flare-out. There is another plus - there is not much wood to buy. So lets build!

WING: Although the wing plan is tapered, and the lead-ing edge is swept. all but the pair of tip ribs are the same chord (the ailerons taper). This results in plenty of thickness at the tips to delay stall. Use light quarter grain for the ribs, and note the recess at the top on the centre section.

Select hard, springy strip for the spars; 1/8 square for the bottom, and 1/8 x 3/32 for the top. The 1 mm leading edge sheet helps to beef this up to the same strength as the bottom one. The LE and TE are light but firm 3/16 square and a strip of 1/16 x 3/16 forms a false LE to add strength, because the bottom has no sheet out-board of the centre section..."

E-4 Electric from Silent Flight June 1997.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction