Getting The Dihedral Right On A Vic Smeed Tomboy.

[David Davis]

I have told this story many times so apologies to those who already know this. It was my Uncle Geoff who taught me how to build model aircraft. He died young of cancer in 1961 but before he died he gave me all of his models including a Tomboy and the fuselage of a double size Tomboy. He had drawn up plans for a double size Tomboy, being a draftsman by trade, but over the years the wing plans have gone missing.

Thirty years later, after the sex 'n' drugs 'n' rock 'n' roll years, I completed his double size Tomboy, finished in the same colours as his 36" version. Picture of the model, barely powered by a PAW 19, with my much younger self below.

Unfortunately the years had not been kind to either to Geoff's balsa wood or to his glue joints so I built a second fuselage with all of the joints glued together with cyano and I fitted a Merco 35 in place of the PAW. This cured the lack of power but being a novice pilot in those days I somehow got the model into a spiral dive and when it hit the ground I was left with a big bag of balsa kindling!

I built a third fuselage but was hardly any better as a pilot when I crashed it into a tree and broke the fuselage.The wing and tailplane were not damaged so I put them in a big cardboard box and brought them with me when I retired to France. During the lockdown I built a fourth fuselage but given its very light construction, I decided to fit an electric motor. Pictures of the fuselage in the course of construction below. Note the immaculately tidy work bench!

I have examined the wings which I built in two halves joined together with steel rods to make transport easier and have found that the dihedral is lower on one wing than the other.

As I no longer have Geoff's wing plan, can anybody tell me what the dihedral measurement should be on a 36" Vic Smeed Tomboy? I will then adjust my wings accordingly.

Incidentally, while electric flight is not my major interest, I found that it was good fun to run up the motor on a variety of props to see what current it was drawing. Depending upon the propeller it drew between 30 and 40 amps on a 3S LiPo which should be enough for a model of this type and an anticipated weight of between five and six pounds. (2.5kgs - 2.7kgs.)

[EarlyBird]

Three and a half inches on each tip according to this

Tomboy plan

Hope this helps.

Steve

[David Davis]

Thanks Steve, I'll work on seven inches for my model then.

[brokenenglish]

And the dihedral brace from the original plan should obviously still give the correct angle.