Kit FF59 Royal
Aircraft Factory SE5: Gasoline Conversion
Using a O.S. .20 Four-Stroke Engine.
Written by Sam in Arizona, June 24, 1996
Sirs:
I have just returned from the test flight of my latest Easy Built kit a 50"
wingspan R.A.F. SE-5 (kit FF59). This is my second kit from your company. My
first was a Jodel D-9, 50” wingspan originally designed for electric flight. I
powered it with an O.S. .20 four-stroke engine, cut ailerons into wing and used
standard servos. It flew well, but was grossly overpowered. A low-speed,
low-altitude accident ended it’s career early. Only later did I learn an
incorrect wing incidence setting was to blame for its vicious stall
characteristics, not the kit design. Recently, I happened upon an advertisement
in one of the model magazines advertising a 50" wingspan, jumbo free flight
SE-5. Out of curiosity, I ordered one, knowing full well that this aircraft was
close in size to a Sopwith Camel F-1 I had built about 10 years ago. The Camel
was powered by a .91 four-stroke, covered with silk and dope, and flew quite
realistically.
After receiving my Easy Built kit FF59 of the SE-5, I sat down at my computer
and fed in some numbers. The weight, wing area, power, and construction looked
like it should fly with the same O.S. .20 four-stroke engine that overpowered
the Jodel D-9.
I started off with a light-ply box that tied the engine, landing gear, wing, and
Cabane struts together. Then I built the plane around the box, exactly as the
plans show. Of course, I had to add some spars to the wings that also serve as
anchors for the ailerons. The leading edges of the wings are 3/16" hardwood
dowels, and the main spars are spruce. Cabane struts are streamlined aluminum
tubing, and the wing struts and landing gear are also spruce, the same size as
shown on the plans. This proved to be quite strong and for safety, I added
aramid-kevlar cables for bracing, these are also adjustable for rigging.
The plane was rigged with all surfaces and the engine at 0° to the datum line of
the fuselage. I later rigged the upper wing at 2 ½°+ to improve the stall
characteristics. After my first test flight, I have found it necessary to add 4°
downthrust to the engine.
The plane was covered with the silkspan tissue that came with the kit, it
appears to be a very high quality covering. Three coats of clear nitrate dope
and two coats of colored butyrate dope gave the structure surprising structural
and torsional strength. I am presently hand-painting the various roundels,
numbers, and insignia. The instrument panel was used as a model to fabricate one
on my computer using photographs of the instruments, gages, and controls. Then
they were printed on glossy paper and fuel-proofed. The control system was made
up of aramid-kevlar cables routed over pulleys and fairheads duplicating that of
the original aircraft. The aircraft flies quite smoothly and realistically with
the O.S. .20 four-stroke turning an APC 11x4 propeller with no tendency to
tip-stall or any other nasty traits associated with biplanes.
The only thing that put me off at first was the lack of die-cutting. But, I've
seen some really good kits that were all but ruined with bad die-crushing. I
have three models partly built because the die-cut parts were unusable. Cutting
printwood is not difficult if one takes his time. Laser cutting would be ideal,
but costly. I think maybe printwood was actually an advantage in a kit-bash
since many parts were modified before they were cut out saving wood in the
process.
I will always have something good to say about Easy Built Models and I will
heartily recommend them to anyone wanting a challenging, well designed model
kit.
Thanks again for a very good kit design. I will keep in touch.
Sincerely,
Sam
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