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Anyone can build a model plane.

44" Tomboy

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Michael Richardson 410/05/2018 12:23:53
14 forum posts
1 photos

Anyone can build a model plane! This is a record of my progress as I share how I build the classic Tomboy for electric. It is a simple pleasure for anyone wanting to learn how to scratch build from plans.

Michael Richardson 410/05/2018 12:49:07
14 forum posts
1 photos

The Tomboy is a great project and has been for many years for builders all over the world. The first thing required is a plan. You can easily obtain one here for free: https://outerzone.co.uk/plan_details.asp?ID=285. This is a PDF document and was easily printed at my local Office Works for cheap. For those interested, I am located in Melbourne, Australia. Once I have the plan I then spend some time looking over it seeing where the RC can be placed. This will be an ongoing thing as the model comes together. It is also important to note that the Tomboy was not intended for RC but it can be easily be converted and makes a fantastic 3 channel model. I will redraw the fin and alter the tailplane to suit RC. For tonight I have spent some time tracing components onto grease proof in preparation for cutting, This includes tracing the rib templates, formers, side cheeks, fin outline, sub rudder, dihedral brace and the cabin top. Overall there isn't alot of components and the remainder is simple framework. win_20180510_21_17_55_pro.jpg

kc10/05/2018 22:06:51
5570 forum posts
163 photos

it is worth noting that a set of laser cut ribs and parts are available for 15 pounds inc postage ( in UK ) from  iGull   for anyone who wants to speed up the build.

Edited By kc on 10/05/2018 22:08:18

Chris Freeman 311/05/2018 05:26:20
89 forum posts
91 photos

The Tomboy is a great model. I am part of a Vintage Model aircraft group, that has mostly vintage moddellers as well, and it was suggested that we use the Tomboy as a one design climb and glide aircraft as used by many clubs overseas. I looked at the design with my mate who has a lazer cutter and we decided to modify the airframe to suit the skills and pockets of the club members. We enlarged the airframe 10% so standard 9 gram servos and electric motors could be used without having to use smaller equipment. We also changed the spar design to a 2 spar with shear webs as the single spar can be weak. we also added turbulator spars to increase strength and lift. Standard covering is also not a problem at this size and most airframes are built with the longer span wings and tailplane.

A local hobby shop stocked all the equipment needed as postage in South Africa is very unreliable and courier is expensive and also the older members do not like internet. We first thought we mike have to make around 24 kits as they were made in batches of 8 for cost. We have now made over 160 semi kits with most being built by first time builders. The longest glide we have had is 28 minutes from a 1 minute motor run.

Michael Richardson 411/05/2018 12:05:18
14 forum posts
1 photos


Hi Chris, a 28 minute glide is brilliant! Thanks for the share smiley. For anyone starting out with model building, if you can get some laser cut parts that is a great way to go as it makes the building a bit more relaxed. I have seen a few Tomboy short kits advertised on Ebay for good value.

Carrying on from last nights work, today I managed to cut out the ribs from the tracings I made. To do this I laid down the tracing over some 1/16th ply and pin pricked the pattern. Then I just draw the pattern on the wood and cut it out to make a template. This is my preferred method however it is good to note that there is more than one way to do this. Another way I transfer patterns on to wood is to trace on white tissue then spray a light coat of spray adhesive and stick to the wood then simply cut it out then remove the tissue, this is good for more detailed parts.

20180511_094214.jpg

Michael Richardson 411/05/2018 12:13:01
14 forum posts
1 photos

Here are all the wing and tail ribs ready for the glue up. Next I'll cut my spar, trailing and leading edge. As i'm going for the 44" version I'm going to use spruce for the spar and hard balsa for the leading edge. As for the trailing edge this will be medium balsa that I will pre-shape with my razor plane and notch prior to construction. It's a pretty simple wing and has a constant chord making it great for beginners. As Chris has pointed out you can also add a top spar if you wish for added strength; you can just add an extra notch to the template.20180511_204502.jpg

Cuban811/05/2018 13:08:08
2069 forum posts
3 photos

Three bob for the plan!

Percy Verance11/05/2018 14:04:29
avatar
6833 forum posts
138 photos

 

I've said it before I know, but I'd avoid spruce. I'd go for cyparis, which is lighter and stronger than spruce for any given section. Cyparis also has the advantage of being free from the natural oils which spruce has within it which can, over time, debond a glue joint....

Cyparis can be had from Solutions or Blackburn Model Supplies a.k.a. Balsamart (who get it from Solutions).

Edited By Percy Verance on 11/05/2018 14:06:11

Michael Richardson 412/05/2018 11:22:57
14 forum posts
1 photos

Hi Percy, cyparis sounds good but it's a bit tricky to source here in Australia as most hobby material is so spruce will have to do. I have also some Tomboy's with a carbon rod spar which looks effective.Today I started cutting out some of the spars and leading and trailing edges. This is simple enough to do, I just make sure I use sharp blade and take multiple passes. I am going to build each wing panel separately and then join them to the centre section when I add the dihedral brace so in preparation I have made an angle gauge for the two centre ribs and used this to mark and cut an angle for the ends of the main spars where they meet in the middle. I hope to get some of the tailplane constructed soon.

win_20180512_20_05_34_pro.jpg

Percy Verance12/05/2018 14:01:19
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6833 forum posts
138 photos

Ah, sorry Michael, I had no idea you were in Oz........

Now that I've re-read your first two posts, I see it.....

Michael Richardson 413/05/2018 13:28:20
14 forum posts
1 photos

The tail plane is easy construction and comes together nicely. Firstly I lay down my spar, leading then trailing edge using the rib as a distance marker. A good tip I find helpful is to use the metal ruler and hold it against the edge of the wood while pinning to ensure it's straight. I use Selleys' white glue and thin it down with about 10% water which makes a good bond and is a lot cheaper than using CA. I have shorted the width of the leading edge to allow for the addition of an elevator which I'll make from hard balsa as it will be a long strip. 32456140_1280983342036689_8081100715407179776_n.jpg

Andrew76713/05/2018 16:23:57
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755 forum posts
4 photos

Michael

I'm watching this with interest. I have the plan but have never got around to building it. What do you intend to cover it with?.

Andrew

P.s....Nice work by the way...

eflightray13/05/2018 18:30:55
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454 forum posts
100 photos

Michael, I don't know if you have managed to glue your build to the plan yet, (not the right way to 'cover' a model, but clear polythene sheet is good stuff to cover a plan with, even cyno and most adhesives shouldn't stick to it. There are other clear films you can use, just do a quick 'will glue stick to it' test first.

Plus, always remember to add lightness, build to survive flying, not to survive crashing, (unless you're into concrete and steel structures, and IC power wink ).

Ray.

 

Edited By eflightray on 13/05/2018 18:31:29

Martin Dance 113/05/2018 18:37:09
162 forum posts
33 photos

My Tomboy is covered in Litespan, and fuel proofed, can't remember what I used. Its powered with an Irvine Mills 75, more than adequate. It only has the Mills integral tank and flying carefully gets to around 500'. If I built it again I would only put an elevator on one side, after all it's basically a trimming control with a bit extra to slow the touchdown.

Michael Richardson 413/05/2018 23:55:16
14 forum posts
1 photos

Hi Ray yes this is good to note. I have been scratch building for many years and know not to glue the model to the plan. I usually use grease proof paper as it is cheap and works well, you may not see it well in the photo. You can also use the backing of covering film.

Hi Andrew, welcome to the forum, as for covering my Tomboy, I am limited in my choices as in Australia as we just don't have some of the nice lightweight iron on films that are available in the UK. So for a bit of nostalgia I am going to simply cover the model with tissue and dope. Fuel proofing isn't an issue as it's electric. I'll be interested to know if any of the Australian modellers have any links to lightweight covering material.

Michael Richardson 414/05/2018 14:42:37
14 forum posts
1 photos

Work on the wing started today. This was pretty straight forward much like the tailplane with a few extra considerations. The centre ribs were altered to allow for the top sheeting and dihedral brace and a dry fit was done. Everything gets dry fitted, very important . The trailing edge notches were then marked and cut out, I use a simple shaving razor blade for this, works great! All that there was to do was to lay down the spar and trailing edge and glue in the ribs. I always take my time ensuring that the fits are good and that everything is square. I used some scrap balsa to hold the spar straight and plenty of pins. When pinning I try not to pin through the wood too much but more so use the pins as hold downs. Using the exact same method I aim to get the second wing panel and centre section completed in the next few days.32389212_1281702365298120_8440839793071357952_n.jpg

32464403_1281702371964786_163180174240645120_n.jpg

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Michael Richardson 417/05/2018 12:21:38
14 forum posts
1 photos

A few days since my last posting and have made a little bit more progress on the Tomboy. Both wings have now been constructed and joined with the required amount of dihedral. Prior to gluing I use my trusty razor plane to shape the leading edge and wingtips. The trailing edge is already pre-shaped prior to the glue up, I find this method easier as planning and sanding the trailing edge when glued to the framework results in broken ribs face 7.

I always use a truly flat and longish sanding block to sand down the wing and if everything is glued well not much sanding is required smiley.

To add the dihedral I pinned the centre section trailing edge and lower spar onto the plan. It's good to mention to that I cut a 1.5mm rabbet in the trailing edge to allow the top sheeting to sit comfortably and also did the same for the top spar. Using some scrap pieces of foam board I cut out some basic uprights for each wing to sit on as the dihedral brace and two wing halves glue. I decided to keep to the original dihedral as per plan which is 3 1/2" (89mm) on the 10th outer rib.

32805045_1283553348446355_8418430564981276672_n.jpg

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Once all dry I added my top sheeting while still having the dihedral uprights in place. This was a fiddly job that took a bit of fitting but with some trial and error I got a good result. Once this is all glued I can carefully remove the wing from the plan, give the centre section a sand and put the wing away until I'm ready for covering smiley.32787704_1283553221779701_4566940422072434688_n.jpg

In my next posting I hope to have cut the formers out in preparation for the fuselage construction.

PatMc17/05/2018 21:46:52
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3798 forum posts
479 photos

Nice job your making of the Tomboy, Michael. thumbs up

Have you considered covering tissue over "Doculam" ? It would be a natural for the Tomboy, give it a genuine vintage tissue appearance but tougher than any film or Litespan. Involves a bit more work but IMO well worth the effort.

There's a guy, danny mz, in this RCG thread posted yesterday offering to sell doculam. He even lives near you - well nearer than me - he's in Vic & only about 350k from Melbourne. wink 2
Just realised in the same thread there's also a guy, Humphry1957, in NSW selling it. Humphry reckons quote "I can get a 44" tomboy wing covered with less than 1/2 metre Work that out $2.50 per model."

Keep posting progress on your Tomboy. thumbs up

Cheers
Pat.

Michael Richardson 418/05/2018 04:36:37
14 forum posts
1 photos
Hi Pat, thanks for the post. This intrigues me i do have some questions. Its iron on? Do u need covergrip or balsaloc to seal it? And the big question is how do u apply and seal the tissue? I dont have an RCG account but might look into it.

Cheers,

Michael
Michael Richardson 418/05/2018 04:36:38
14 forum posts
1 photos
Hi Pat, thanks for the post. This intrigues me i do have some questions. Its iron on? Do u need covergrip or balsaloc to seal it? And the big question is how do u apply and seal the tissue? I dont have an RCG account but might look into it.

Cheers,

Michael

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