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F/F Tomboy converted to S/C

Posted: 29 Apr 2019, 07:20
by Wayne_H
Following on from my original post viewtopic.php?f=53&t=432

It's taken longer than I'd anticipated to get such a relatively simple conversion completed!?! :oops: I typically have several projects "on the go" concurrently - that way, if I start to lose enthusiasm or its impractical to undertake a particular task such as sanding or painting when I have the time, I can utilise the available time working on something else.

The Tutor wing has been repaired, sanded to a more aerodynamic profile and made ready for covering with laminating film & tissue, using the same methodology I employed on the (new build) tail-plane. I didn't sand off every last bit of the silver enamel or re-straighten the crooked ribs, to leave a visible connection to the origins & history of this 50+ year old wing. The fact that the Tutor flew so well in it's original "as built"(?) condition says great things about the original design. :ugeek:

I'm still undecided on which radio functionality to install - GG, 1+1 or compound action - my current leaning is towards an Adams magnetic actuator and a 1+1 Tx. The Mills .75 is to be replaced with an electric system.

Re: F/F Tomboy converted to S/C

Posted: 10 May 2019, 05:40
by Wayne_H
More progress...........

The Tutor wing having been repaired & sanded to a more aerodynamic profile, has been covered with laminating film. I was going to then tissue it, but I decided to forgo that as eventually this wing will have a Tutor fuse & tail-feathers built for it and I have a different colour scheme in mind for that machine.
surprising how much the rounded wing tips change the Tomboy look!
surprising how much the rounded wing tips change the Tomboy look!

Consequently, coloured trim tape was applied to the laminating film covering, to give some contrast & colour consistency with the rest of the Tomboy. A genuine Tomboy wing will be constructed (eventually 8-) ), so it will be finished the same as the existing (new Tomboy) tailplane.
finished_3_s.jpg
finished_1_s.jpg

The Mills .75 has been removed & replaced with a 2212 2200kv outrunner mounted on a new firewall after the old engine bearers were shortened. The nose of the Tomboy fuselage was painted red - mainly to hide previous wear & tear while sealing off the new motor former and maintaining the overall colour scheme.
nose job.jpg

Radio wise, I opted for a rudder servo - easier & quicker :P . It's surprising how much additional time & effort goes into a retro-fit/conversion, time that is not required in a new build when the necessary features are included in the new structure as you build. e.g. servo rails, pushrod & radio installation, rudder (not a trim tab), battery box, cutouts in formers for motor wiring, etc., etc.
original trim tab incorporated into the new rudder
original trim tab incorporated into the new rudder

Make the rudder push rod, complete the radio installation, balance and then test fly :D :D

Re: F/F Tomboy converted to S/C

Posted: 26 May 2019, 13:44
by Wayne_H
Test flight time (finally... :oops: )

Very pleased to report that the Tomboy Tutor is a resounding success. I was prepared for it to be slightly under powered, but the power was just right, cruising around maintaining altitude at mid-throttle & climbing nicely at full power. The only changes needed are a little more down thrust & moving the rudder clevis in one hole on the rudder horn for a more immediate rudder response.
It was a good test flying session. The Sigma also got it's first air under its wings.
It was a good test flying session. The Sigma also got it's first air under its wings.

TOMBOY Vital stats:
  • Motor 2212 1400kV
  • Prop 8" x 4.5"
  • ESC HK 20A
  • Battery Zippy 1300 Mah 2S
  • Power 50W static measured
  • Mass 450g
  • Radio 1+1 Tx (using Phil's code on an ATTiny85 )
Before the first flight
Before the first flight

I had 4 or 5 flights all up. On the last flight, late in the day, the Tomboy wouldn't come down, just floating around with the motor off in the buoyant air for over 10 minutes. :D Yes, I'm chuffed :lol:


Re: F/F Tomboy converted to S/C

Posted: 26 May 2019, 14:50
by MaxZ
Congrats Wayne!

Max.

Re: F/F Tomboy converted to S/C

Posted: 26 May 2019, 21:25
by Sunbird
Well done Wayne and thanks for posting.
Regards
Ian