P-51A from TF red box kit - Page 5 - RC Groups
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Feb 09, 2013, 10:20 PM
Cohen the Barbarian

Made a start on the turtledeck

Put the first 4 formers in place. I am not using the supplied 1/4" material for the top, so all the formers have to be recut. Also the rear section will be built separately, initially as a hatch giving access to the controls, I will probably close it permanently when glassing.

I have cut out the windows for the counterbalances on the rudder and elevators and will be making these parts up over the next few days in parallel with the turtledeck.

I have also done some calculations. As designed, the wingspan has been increased by 2.5" from the correct proportions. I am pondering whether I should shorten the wings outboard of the dogleg to get the correct planform, but at the cost of about 26 square inches of wing area. I will have a better idea when the fuse is complete and I can sees how much it weighs...
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Feb 09, 2013, 11:09 PM
Registered User
Ldm's Avatar
Looking good buddy
Feb 11, 2013, 06:39 AM
Cohen the Barbarian
Got one side of the first layer of the turtledeck in place. It's at the limit of making the balsa take a compound curve. Second layer will be in 3 pieces, centre and 2 sides, putting the joins in different places.

I have also grafted the counterbalances onto the rudder and elevator cores. These parts will wind up with 5 layers of balsa with grain running in alternating directions. Elevator is actuated with a torque rod, elevator halves will have a tube embedded for it to work against.

To those who make encouraging comments, thank you. To those who look and wonder if you could do something similar - Have a go. It really feels special to see a project taking shape.
Feb 11, 2013, 08:41 AM
Registered User

Great suggestion

Great suggestion
I will be soon trying to convert an Old "Sterling" P-51D to a "B"The Fuse and wings have allready been started(By someone else?). I have the Cowl and the Canopy for a "B" and Must build up the Fuse to make a "B". The Foam idea will save me a lot of work on fixin the The area behind the canopy.Have also Completed a rather Crude conversion of an old early(80s) ARF P-51d into a P-40 (Sorta) see pictures attached (I hope)
Feb 12, 2013, 06:52 AM
Cohen the Barbarian

Plugging away

P-51D to P40 - Yikes , sounds interesting though...

The second side of the turtledeck has its' first layer of balsa, I will start on the second layer tomorrow.

The elevator halves now have 3 laminations, 2 more to go. The rudder has 2 laminations in place. The counterbalance tabs are no longer at imminent risk of snapping off.

Once the laminating is done I have a sure fire way of sanding them accurately to profile. (watch it go wrong after a claim like that )
Feb 14, 2013, 03:20 AM
Cohen the Barbarian
Progress is being made, but nothing that looks good in a picture.

The laminations of the elevator and rudder are done, the last layers are curing under a pile of weight. Just looks like 40 odd pounds of lead shot sitting on a board, which is actually distributing the load onto the parts underneath.

The second layer is going on the turtledeck, closing the gaps and holding everything together.

With a little luck all these parts will be completed at the weekend, or early next week. I still need to make jigs for shaping the rudder and elevator surfaces accurately.

Hope everyone else's projects are coming along smoothly as well.
Feb 15, 2013, 06:06 AM
Cohen the Barbarian
Latest update:

The main turtledeck panels have been cut to shape, then moulded to shape after soaking in methylated spirits (denatured alcohol).Once fully dry I will glue them in place, then there will be a couple of small strips required to finish the deck.

The blanks for the control surface shaping jigs have been cut. it will take about an hour of time, 6 alloy strips and 12 screws to finish them, then another hour or so to shape the surfaces... pictures will be forthcoming and will (hopefully) show how this works with a minimum of words
Feb 18, 2013, 04:34 AM
Cohen the Barbarian

The rudder is done!

Had a chaotic weekend, but finally got to the workshop and made some progress.

The rudder has been shaped... sounds easy, and really it is not hard, but there are a lot of steps with a definite order if you are to get a good result.

1: Shape the counterbalance to fit accurately in the cutout in the fin.
2: Hinge the rudder - it will be more accurate done now than later.
3: Measure the thickness of the trailing edge of the fin (Le) and the thickness of the rudder blank (Th). Decide on the thickness of the trailing edge you want on the rudder (Te).
4: Set the heights of the guide rails on the jig - Leading edge at Th-(Th-Le)/2, Trailing edge at Th-(Th-Te)/2
5: Check the calculations and height of the rails
6: Repeat steps 4 and 5 as necessary to get it right.
7: Place the blank in the jig, sand sand sand until the sander is running on the guide rail on both sides.
8: Reassemble the jig to give leading edge thickness Le and trailing edge thickness Te. Note that this will require using the other side of the jig...
9: repeat the check and correct process.
10: Sand some more.....

This took a total of about an hour or so, and resulted in about 1/3 of the original blank being reduced to a fine powder. On the plus side, the rudder is straight, strong, light as a feather and just about perfectly shaped

The front section of the turtledeck is also finished... as I look at the profile I am awestruck by the sleekness of this birds lines .
Feb 18, 2013, 08:16 AM
Registered User
Ldm's Avatar
Nice work , looks great
Feb 19, 2013, 06:21 AM
Cohen the Barbarian
Thanks LDM, the support means a lot to me.

Lots of other stuff came up today, got the stab halves hinged, but that was it. Hope to get them profiled tomorrow.

I dummy up the canopy, tail feathers etc. regularly to encourage myself.

Another thought for those contemplating building - it's a great way to relax after a tough day at work , just go to the man-cave (or woman-cave, don't want to seem biased ) and focus on doing something creative for an hour or so.
Feb 20, 2013, 06:35 AM
Cohen the Barbarian

Did it all again...

twice. The 2 elevator halves have been profiled, no problems encountered. It only took about 20 minutes longer to do the two than it did to do the rudder, most of the time is taken in the setup.

Having weighed the 2 sets of parts as shown, the new parts are about 35 grams heavier, but most of that is accounted for by the hinges and torque rod mechanism in the production parts, which would have been needed for the others.

On the down side, the replacement parts are about a quarter ounce heavier. The pluses include - Stronger and straighter, better looking profile and the counterbalances are cool. Also it helps to remember that the fuselage sides lost about 5 1/2 ounces from the tail area.

It was time consuming, but the results are very satisfying .

Next step is to finish the turtledeck and work on the belly scoop.
Feb 20, 2013, 11:43 AM
Scale Builder
It's shaping up nicely Genghiz, great work.
Feb 20, 2013, 04:26 PM
Registered User
Gree's Avatar
You are doing some good work here. I am following along and enjoying each post. It is also good to see you experiment with some different building techniques. I can't believe how fast it is coming together...

I'm looking forward to the next instalment.
Feb 20, 2013, 07:24 PM
Registered User
Ldm's Avatar
Looks great really motivating me to start my P40
Feb 22, 2013, 06:18 AM
Cohen the Barbarian

Starting on he rear of the turtledeck...

After a couple of days full of other stuff , I have made a start. This section may be a bit fiddly, small parts and awkward areas for sanding, particularly the fin to stab fillet.

The section currently underway will be made as a hatch, it may be closed off when I do the glassing, I haven't decided yet.

As an aside, all formers need to be cut from scratch due to changed construction methods, for example the factory version of the turtledeck has a 1/4" top panel, where mine is sheeted to a thickness of 3/32". On the other hand it means I have a full set of templates to make another...

Once again thanks for the positive comments and suggestions, and know I enjoy reading your logs as well.

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