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Old Apr 15, 2011, 07:54 AM
I like real wooden aeroplanes!
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South-west France
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Not ANOTHER Tomboy!

Yes, I'm sorry it is. My excuses are:

1. Despite building lots of Smeed designs - Paageboy, Mam'selle, Pushy Cat etc., I never built a Tomboy first time around.

2. We have lots of accessible little lakes around here, and I have never had a float plane - what better than the Tomboy

3. I fancied a nice simple airframe for a change.

So, although it is just another Tomboy, it is on floats and it is electric - and I won't be able to resist("improvements??) bits of modification en route, no doubt.

Hopefully this will be a fairly quick build.

Started with the wings. After cutting out the ribs using a 1/16" ply template, the first job is to assemble the spar with the 1/16" ply brace. Then pin this down and build the centre section on top of the bottom sheeting. First deviation is evident here, the original has sheeting on top only. Also, it has but one spar, on the bottom. This model is to be covered in mylar and jap tissue, with no top spars it WILL warp upwards, so I have added two 1/8" square top spars to balance the structure.

Once the centre section is dry, tip it over and build the left wing. BTW, as this is a radio model, dihedral is reduced to 2.1/2" per side from the 3.1/2" of the FF model. That'll do for tonight, leave everything to dry

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Old Apr 15, 2011, 10:48 AM
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Juat can't have too many Tomboys
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Old Apr 15, 2011, 12:57 PM
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oh yes you can.

little blighters everywhere!!!
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Old Apr 15, 2011, 01:29 PM
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Sorry Adam - didn't mean to upset you (again)!
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Old Apr 15, 2011, 04:18 PM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
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Hey Adam, I'll be in Southampton for a week in early May. Anywhere to fly a Tomboy there??
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Old Apr 15, 2011, 05:58 PM
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Tomboy's could be taking over the world....and why not. Have fun.
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Old Apr 16, 2011, 12:22 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
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Well, why not. There are a lot of worse things that could be taking over!

We now have wings. I sneaked down early and built the right half, so by breakfast time the wing was ready for centre sheeting. Another mod has crept in, the sheeting extends over the first two half bays outside of the flat centre section, top and bottom. I also added corner gussets each side of the spar, LE and TE joints at the centre and in the corners at the tips. As designed for F/F the wing is fine, but easy to over stress when flying R/C, so this is a bit of insurance for trivial extra weight.

I am still very weight concious, mind you, lighter aeroplanes always fly better, and the wood has been very carefully chosen. I was lucky to have some really nice quarter grain 6 lbs/cubic foot 1/16 for the ribs, the lower spar is rock hard, the LE medium/hard and the TE and sub spars medium. Oh yes, one other thing; if the TE looks wider than on the plan - well it is. I didn't have any 1/2" trailing edge, and out here in the sticks of rural France you can't just nip out to the model shop (I order my balsa in decent quantities from the excellent Balsa Cabin in the UK). I did have some nice 3/4" TE and rather than cut this down I shortened the ribs.

So, cyano some light 1/4" tips on, then half an hour on the terrace with the sanding block and we have a completed wing. Finished uncovered weight 34 grams/1.1/8 ounces, quite satisfactory despite the wider TE, extra spars, sheeting and gussets.



BTW, the plan you can see in the photo of the completed wing is obviously not the Tomboy, it is a print of one of my own designs, the Diet Sundancer E400 electric soarer - I drew up the Tomboy plan on the back from the reduced scan in the excellent and indispensible Vintage Plans thread.

Tailplane next!
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Old Apr 16, 2011, 02:31 AM
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Looks good - the extra strength is a good idea - I learned the hard way
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Old Apr 16, 2011, 05:03 AM
Scott R/C Time Pilot
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NorthBend/Coos Bay,Oregon USA
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Very nice work on your Tomboy. Let me know how the floats work and fly, I want to retro fit a set to my 40" Tomboy.

Scott
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Old Apr 16, 2011, 05:10 AM
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Tomboy

Yep, lookin' good Sundancer. And I concur, strengthening the wing for the RC version a good idea. I speak from personal experience - the start of a new wing is on my building bench! I might add with strengthened spar and extended dihedral braces. You must be one of the few modellers that hasn't built a Tomboy sometime in their early modelling career Mine is my third. Enjoy the build. Allen
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Old Apr 16, 2011, 06:09 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
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Hi Allen

Yes, I don't quite know how I missed the Tomboy first time around. I am really enjoying the build - a sort of "getting back to basics" experience.

Scott; yes, I'll be posting the full story when it comes to flying. Plan is to fly it first with the interchangeable wheel u/c just to get everything sorted out, then try it with the floats over the very long, soft grass of my flying field to make sure there are no unexpected trim changes, then on to the lake in our friends garden, which is when the fun should really start.

Been busy since posting and I now have a tailplane. This is normal size, but I have cut back the ribs and used a 1 inch TE, which will be cut off to form a 3/4" elevator, joined with wire. I want to be able to still strap the tailplane on, as I would like the model to be as portable as possible. Of course it will need keying so it can't move, but that is the system I have used on the bigger Spartan and it works fine.

Mods on the tailplane was to use twin centre ribs spaced 3/16" apart ready to accept the fin/rudder and to add two 1/8" x 1/16" top spars to balance the spar structure and discourage warping upwards under the pull of the covering.



I shall need to add some 1/16" sheet either side of the centre ribs for covering attachment.
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Old Apr 16, 2011, 06:33 AM
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It is a pleasant plane to build - you could also go wih 1 long elevator, and just have a slight angle on the back of the rudder, its a bit simpler? This plane pretty much goes up and down with just the throttle - I only use the elevator to slow her down a bit?

Looking really good!
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Old Apr 16, 2011, 07:23 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
Joined Sep 2007
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Hi Owl

Reason for the split elevator is that I do want the tailplane removeable and am going to strap it on with rubber bands - can't do this with a one piece elevator. Also, doing it this way the wire-in-tube centre joiner provides one ready to go hinge, just a couple of mylar ones further out then needed.

Just finished the fin/rudder. Hinge line is along the original upright spar which is now made double width so the rudder can be created by cutting down the middle. This is a big rudder and will only need a small angular deflection. Here it is plugged into the tailplane (but not glued yet of course until after covering) Total weight of tailplane, elevator, fin and rudder is 20 grams/5/8 ounce.



Fiddly bits still to do on the tailplane and rudder - surface sheeting at centre for covering attachment, 1 mm ply inserts for control horns and TE reinforcement to take rubber bands, carbon fibre LE reinforcement for the same reason.

I try very hard to anticipate all the probable "wear and tear" points on models when building and build-in the necessary reinforcement - I like (and expect) my models to last a long time!

Fuselage later today I hope.
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Old Apr 16, 2011, 02:53 PM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
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Bit more progress.

The basic fuselage sides are built; I found it helped greatly in producing them accurately if the (fairly hard) front bottom and rear top longerons were steamed into approximately the required curves before starting. If you don't do this there is always a chance that the springiness of the bottom longerons in particular will distort the shape of the sides once they are unpinned from the plan. I always build the second side directly over the first, with polythene sheet in between, to ensure that the two are identical.



While the sides were drying I cut out the six float sides from 1/8" balsa and joined them with the leading and trailing edges. The centre 1/16" ply formers with the wire legs sewn to them for the front floats, and the ply box to take the sub fin for the rear float (1/16" sides and 1 mm bottom) were added when the basic assemblies were dry, taking great care to get the angles right. I deviated with the sub fin construction, using a 1 mm ply core and 1/16" balsa each side, as, rather than fixing this with rubber bands as on the plan I decided that I will insert aluminium tubes and fix it with a 20 swg pin through the sub fin.



The fuselage cross braces are all ready, cut to size and the formers F3 and F4, rather than being solid as on the plan, are built up "rubber model fashion"from strips of 3/8" x 1/8" hard, the reasoning being that this will be better than making lots of holes in the solid ones for wiring, elevator snake and rudder closed loop wires. So fuselage joining next, using a jig to make sure it stays straight.

Bed time!
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Old Apr 17, 2011, 01:50 AM
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Sundancer,

Come on over! Beaulieu Airfield is a public site and in the New Forest. 5 permit to fly all year.

I dont HATE tomboys per se, its a nice simple design . My bug is with the Tomboy competitions that have taken over the local vintage meets. They need there own flightline.
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