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Anything I need to knowabout large depron wings..??


Cyclicscooby
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Hi Guys..
 
I've built a couple of Depron models now, one 36" profile, one 32" full bodied Bipe, but both have flat sheet wings..
I've also made Petes Tailwind, so i'm ok with wing structure, in wood..
 
I'm planning a 1/5 STOLCH build, that will up with 800mm wings, which I want to create using wood spars, depron + ply ribs, and 3mm sheet covering, with a bit of CF thrown in..
The fuse will be mostly Depron, with a Ply sub-structure, but i'm not worried about that so much, its the wings..
 
Is there anything I need to know about, that I wouldn't have encountered so far..??
 
 
Luv
Chrisie.. xx
 
 
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Hi Chrisie, Mr Tom Wright of PL fame will give you all you need to know I am sure. You might have to wait a while ,as he is a very busy man, designing, bulding, test flying and up dating his fleet. I am sure there are many more on the forum (me included) who would like to have more knowledge of this sort of build. Cheers FB3
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There is also a guy going by the name of e-flite ray from Wales who has built a scale Sunderland (90inch) and a Dauntless (around 70 inch) mainly from Depron.
 
Just at the moment I don't have a link but a search will surely find him.#
 
stu k
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Hi Chrisie
A good place to start is an estimation of the AUW ,this should help to optimise the main spar dimensions and materials used.
Torsional stiffness should be no problem if the wing is to be sheeted top and bottom,ribs can also be depron with ply /balsa combination at the root .
A balsa l/e ant t/e makes a good anchor for the depron sheeting,and makes construction easy .
Good luck with the build.
Tom.
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Hi Tom..
 
I haven't a clue what it might be.. ?? I wouldn't know where to start, other than looking at existing models of a similar size, BUT, I haven't yet found a foamy floater, with a W/S of 1800mm...
 
I've scaled down a 3 dim view of a STOLCH750, to 1/5 and have got the following dimensions..
W/S - 1820mm
Chord - 300mm
Length - 1340
 
I've got an E-flite Power 32, 60A Esc, and 4s 3700 sat on the bench, which I fear may be too big for a 1/5 foamie, but it's wot I got..
If I have to make the plans bigger to fit the motor, I will..
 
 
Luv
Chrisie.. xx
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Chrisie.
If its any help I have five own design foam models that range from 5 ft span to 10 ft span .
 
The models that fall into to the 5ft-6 ft span range weigh around 4 lbs ,and as they are all moderate to slow flying the wing loadings are in the range 12 - 15 ozs per sq ft.with power loadings of 80 -100 W per lb .
 
Your project will have a wing area of approx 6 sq ft so a wing loading of 14 oz sq ft will result in a target AUW of 5.25 lbs ,so the wing should be designed to take at least a 4 g load which would be 4 x 5.24 = 21 lbs .If any significant aerobatic performance is anticipated the multiplication factor should be increased.
 
From the information you have provided a wing thickness of 1.5 ins should do and two 1/2x1/4 hard balsa spars with1/16 vertical grain 1/16 balsa sheet webbing in between the ribs.I would also add two 1/4 sq rear spars .All spar joints should be reinforced with 1/16 or 3/32 ply each side.
 
Do keep in mind that the scaling down process from full size can sometimes result in rather small tail and rudder / fin areas .
 
Don't know if that will be of any help ,experiance and the resultant intuition is often a good way to interpret a design, or just have a go but don't cover or paint as this makes mods and changes easy to do.
 
 
Tom.
 
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Wow.. !! Cheers Tom..
 
I was planning on using Ply ribs, with 6mm Depron on either One, or both sides, to give strength and surface, to stick the sheeting too..
 
The ply part will have the mounts for the Slats and Ailerons, as part of its shape, so no bits need glueing on..
The following pics are NOT mine, but show what I mean..
 
Rib layout. Foam-Ply-Foam sandwich rib

Like you said, use wood spars, top n bottom, plus, CF tubes for mounting..
I may also add a lower rear stip to stop any warping at the rear..
Like..

Shud look summut like this, but with the Slat/Aileron mounts sticking out..
 
I'm using this as my Rib template, blown up to 250mm chord.. Minus sheeting depth.
 

Hope to get pencil to paper, and draw the plan, later today..
 
Thanks Tom..
 
 
Luv
Chrisie.. xx
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