Sylph (oz14548)

About this Plan

Sylph. Radio control sport model, for electric power. Wingspan 44.5 in, wing area 360 sq in.

Direct submission to Outerzone.

Quote: "Mythologically, a sylph is an invisible spirit of the air. My Sylph, whilst not being invisible, is a delightful model to fly; stable, a gentle staller, and very trustworthy. She’s also an easy model to build, with about the only tricky part being making the canopy (explained in an attached article from our club newsletter).

Construction is all wood, with shrink film covering. The mock Hoerner wing tips may help low-speed stability, but even if they don’t, they look cool!

As you can see, I originally used niCAD batteries in the Sylph. I replaced them with a 2S lipo when lipos became available. After I gave the Sylph to a friend, he replaced the inrunner motor with an outrunner and a 3S lipo. That lasted for several years, until he gave the plane to another modeler, who promptly lost it.

Wing: Spruce spars (bass can be substituted) and balsa shear webbing make for a very strong wing. Please, do put the shear webbing, grain vertical, between the spars. A simple sanding tool to level the webbing top with the spars can be made by gluing sandpaper to a strip of spar stock. Please see the attached 'Drooped Tips' article for how to build the wing tips.

Tail Surfaces: Very straightforward, build these up from balsa strips. Sand the rudder and elevator to a taper, leaving them about 1/8 thick at the TE.

Fuselage: A simple balsa, ply and liteply structure, build the sides first, then join them over the completed tailplane (yes, just like an Ugly Stik - I only steal/adopt from the best!). Fit the wing, drilling through F3 for the wing dowel. Pin the wing in place, then flip it over, then drill and tap for the 1/4 x 20 wing bolt. I strongly suggest you use a wing bolt that has a hex (Allen) wrench center, so it’s easier to engage.

If you prefer a simpler setup, leave your Sylph with an open cockpit and tap the bolt plate in the fuselage, instead.

Insulate the wing with plastic sandwich wrap, then build the turtledeck and canopy.

I recommend mixing 10-20% rudder into the ailerons, to help with adverse yaw. For the first flights, balance the model on the front of the spar.

Sylph Stats:
Wing area: 360 in. sq.
Span: 44.5 in.
Weight (with NiCads): 40 oz."

Supplementary file notes

Article.
Article (drooped tips).
Article (pop bottle moulding).

CAD file

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