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Sipa S-200 In Depron


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I suppose that either of these ideas will work Steve, you could make one of each and see which you prefer. Because I've been mixing balsa and Depron, I'd probably laminate 1/32" balsa between two sheets of 2mm Depron and form a tab on each end to insert into the fins, that would be very stiff and light. Use your own judgement though, you don't seem to get it wrong so far!

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I was rather hoping that some of the guys that have experience in building from Depron would chip in and offer there input .

But i tell you what Colin that has given me a excellent idea .

I hadn't given it much thought on how i should hinge the elevator but your suggestion seems to solve two problems in one.

So if i make both the tail plane and elevator from two sheets of thin depron and sandwich both together with a single sheet of thin plastic that will stiffen both parts also providing the hinge .

Cheers Steve thumbs up Top Answer

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I would be careful using the same plastic as a hinge and a stiffener, the qualities you need for a hinge is flexibility, which is exactly what you dont want in a stiffener.....

Personally I would go for some a balsa depron /sandwich and mylar type hinges embedded into the balsa

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Good points from Dave. I've found thar even using 1/32" balsa, with the grain running longitudinally, laminated to 2mm Depron makes a very stiff, warp free structure for a minute amount of weight. 1/16"/1.5mm would do it as well, depending on what finished section thickness you are looking for. Using Mylar or furry hinges, rather than cut and insert after laminating, you could put them in first, i.e. Cut out the shapes for the hinges from the balsa, or plastic, and glue the laminate to one piece of Depron, glue the hinges in place, then glue the other piece of Depron on top. Might try that myself the next time! Composite structures are the future((!) (I've got a special talent for waffling).

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Hi ,

I wanted to have ago at building a all Depron model ,

I know i have used wood spars and have realized i could of done it without them in indecision.

I used plastic in the booms / Fins as i felt they might get damage so a little added strength but no loss in flexibility .

The tail plane i could build out of 3/32 Balsa as i already know that will be fine, but it kinda goes against the idea of a depron model .

Dilemma , Foam or wood or both indecision.

I may end up going for wood as the other foreseeable problem is that the control horn is at one end of the elevator and so foam might not give as good a control authority .

Steve

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Hi Steve

Traditional builds use Balsa and Ply - Depron Builds use Depron and Balsa - same difference! if you want to be hi-tech you can always use some carbon rods/strips

As for control surface stiffness - a little carbon rod works wonders (or you could be really rebellious and sneak in a bit of balsa )

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That is coming along very nicely.

"Simon will probable disapprove of this sad"

Not at all.

My only concern using carbon with Depron is the huge difference if their structural characteristics.

Carbon is so much stiffer (and heavier!) that it ends up doing most, if not all, of the work and a small diameter rod or tube in a bigger structure is a very inefficient use of material! smile o

I have found a balsa leading edge to the control surface works well as it acts as a torque rod.

And the control loads are less if the whole plane is built light ............wink 2

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Ok ,

I was going to put this motor in 2826-05 , but i now fear it may well be over kill even if i put a small prop on.

The spec for this motor reports it as a 350 watt motor .

motor1.jpg

motor2.jpg

 

motor4.jpg

A nice snug fit .

motor5.jpg

as you can see the motor is tight up against the formers , but when i have finished to build of the body i will hollow that area out . If it was made from wood it would be self supporting by now , but being foam i will have to glass the outside of it .

Steve

 

Edited By Stephen Jones on 27/06/2015 00:46:49

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Thank`s Gents,

I have re weighted it , and it`s expected AuW will be just over 1 Lbs .

So i have gone through my spare motors and decided to use a 2808/08 on a 5x5 prop i am pulling just over 200w with this one .

So i think this will be a better match for the foam version.

I have made a load of 5mm rings to make up the nose and glued in the motor mount now that i am happy with my motor selection.

Will post some pictures tonight.

I have ordered a canopy so hopefully that will arrive soon as i will be ready for that part soon .

Also i need to put a order in for some servos as that part is also next .

Steve

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The motor mount has now been fitted.

mount1.jpg

I lined up the centers of the body with a line draw on the building board using a set square.

mount2.jpg

And use a battery which was lined up with a perpendicular line to ensure all is square.

mount3.jpg

mount4.jpg

Added some foam packing to transfer the forces evenly onto the lower body.

mount5.jpg

mount6.jpg

Fitting the new motor needed the motor mount reversing so that the wires would pass through the hole , luckily the mounting holes match .

Steve

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Hi ,

Work has stopped me working on this model ,

But i managed to sneak some time on this today.

 

After weighing different Tail plane to help me decide which to go for .

tailplane2.jpg

I tried 5mm Depron found it ok , but needed a little stiffening so added plastic to the leading edge.

I then tried two layers of 3mm Depron and carbon rod.

tailplane1.jpg

And i also weighed a balsa Tail plane .

tailplane.jpg

And as there was only 0.2g of difference between the lightest Depron and the Balsa .

I went for the Balsa as it was the stronger of the three.

Steve

 

 

Edited By Stephen Jones on 05/07/2015 19:46:17

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I have also added foam to the Leading edge of the wings also to the wing tips .

wingtips.jpg

Then it was time to move onto the Speed controller.

esc.jpg

I glued the Esc to the underside of the Air ducting.

esc2.jpg

Withe the wires coming out at the top.

esc3.jpg

This was the glued on top of the sides of the ducting.

esc4.jpg

Steve

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