Ron Marstons Pterodactyl build

20. Complete

19. Fuselage
The fuselage was covered in glass cloth and PolyC. The green is the gaudiest I could find off the shelf at Halford. Hard to believe that some cars are this colour!
The head is not yet covered as this is where any nose weight will go, so I'll wait and see where she balances before this will be the last job to be done.

18. Wing Covering
Wing and surfaces covered in Profilm. The middle shows the motor fitted, and the last shows the Ashlok connector. There are 3 channels in each wing.

17. Wing COvering
Unfortunately the wood on the wings is of differing colour, and I have transparent film for covering, to try and hide the difference I've sprayed the bare wood with a mist of white spray paint. You can still see the wood, but the effect works quite well.

16. Tail Servos
Wasn't sure how best to drive the elevators, there isn't much room in the fuselge with the batteries, and the link runs would look untidy. As luck would have it I have 2 Satrun550 digital micro servos, so these are what I'm going to use, positioned local to the control surfaces.

15. Assembly
With the wing centre section sanded to shape, here is my fix for the earlier mistake of not allowing for the wing shape. I mixed epoxy and micro balloons into a thick paste an seated the wing onto the fuselage. Oh and I couldn't resist putting it all together.

14. Wing sheeting Cont.
With the electrics installed (and tested) I added the bottom sheeting. Then with 3 laminations of 1/16 I made up the LE, followed by all the capping.

13. Wing servos & electrics
The speed controller motor side wires were extended (as per best practice) and as there is a mix of power and signal in such a small area, I separated them out and wrapped them in foil. Not sure if it will make any difference, but it makes me feel like I've done something.

12. Wing servos & electrics
With the top sheeting done it was time to fit the servos and speed controlers.

11. Wing sheeting
This was the hard bit, and took several goes to get it right plus a gadget nicked from the kitchen that was so useful hasn't found its way back yet.

This has 2 curves, the foil shape and the font profile my first attempt was with sheet glued together (with waterproof PVA) and soaked, but as soon as I put pressure on the joint it gave way, so soaking wasn't going to work.

I needed a way to locally relieve the balsa as it went round the various curves. For those trad builders out there you will already know that steam locally applied will give this result, and to help with this I stole the hand held steam cleaner from the kitchen, fitted with its small nozzle is worked a treat, and I was able to steam and bend and glue this awkward piece into place.

With this done I completed the top sheeting.

10 Neck & Head
The neck and head  were assembled over the plan to get the shapes and angles. Spot the mistake - I sanded straight across the place were the wing LE fits, this should be the same shape as the LE. Not to worry, I'll fill with epoxy and filler when the wing is fully sheeted.

9. Fuselage
The tails  and elevators were glued together and sanded to shape, then they were glued to the carbon spars. The first photo shows the tail and rods jigged to the fuselage formers, I then re-inforced the joins with glass and epoxy before fitting the fuselage sides. 

8. Wings ready for sheeting
The next big job for the wings is the sheeting, this is frightening me so while I build up the courage, I'll make a start on the fuselage.

7. Servo and motor mounts.
I'm using Hitech MG125's for the flaps and HS5085 MG for the ailerons, this decision was base on having the 125's and fitting the 5085 outboard for the ailerons as they have more torque and are lighter

I've purchased 2 2217/6 and 2 25A speed controllers from Giantcod the photo on the right shows the mount, its a sandwich of 1/64 ply - balsa -  ply.

6. Wing Build - Doublers, webbing and wing tube
Here we have the ply doubler on the spar join and the shear webs, can you spot my mistake? The middle photo shows the web either side of the carbon wing tube.

5. Wing top spars added
With the spars pre shaped they just slotted straight into the top slots. You may not appreciate this but the top wing has just as much curve as the rest of the model. This will also make problems for sheeting.

4. Wing spars
Using the template files form thethe RCGroups build blog I cut the templates and soaked the spruce spars in hot water for a couple of hours, then clampped both spars into the jig. They dried out  in the jig for about 3 days then into the airing cupboard for about a week, (I wasn't in a hurry).

I had my fingers crossed when I took them out and hey presto they held their shape.

In my opinion this is the only way to do this, clamping and gluing a straight spruce spar to the required shape will put too much stress into the wing.

3. Wing build
Each wing is built over the plan

2. Its Official - I've started.
The rib doublers and leading edge components, drying. A point to note here, taking inspiration from the RC Groups build, I've opted for a carbon fibre tailplane joiner supplied by Probuild-UK in place of the brass tube as shown on the plan. I mention this besause I had to open ou the holes in the inboard ribs and doublers.

1. A look at the bits.
You get a beautifully drawn & printed plan and all the components supurbly laser cut, just like the 3D Fish some of the best I've seen.

Finished model curtosy of

I intend to take inspiration from the RCGroups build blog.