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Anyone else for a Depron Ballerina?


Dave Hopkin
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My initial thoughts

Fuselage - use the plan side views to create the outer walls in Depron, forming the rear part of the Fus in two "boxes" for structural strength, a oblong box forming the main lower part of the fus and a planked turtle deck "box" on top - all using 6mm white Depron for rigity

Forward part of the fus (from F6 Forwards) 6mm Depron Outer with a 3mm Lite ply doubler inside forming the wing saddle, the battery compartment and extending forwards so the end of the battery box forms the motor mounting - with lots of pierced holes and some 6mm square uprights...

Wing would be a simple 6mm flat plate with the ribs split fore to arf either side of the plate to give the correct section

Spars - 6mm Depron sheathed on all 4 sides with balsa - 3mm Hard on the top and 1/16 on the sides as webbing (Depron inside the spar at the root will be dug out to fit a 6mm Hard Balsa brace between the two wing sections

Under Carriage....

Hmm still contemplating this one! perhaps a 1/16 Torque plate from wing root to the outer R2a bonded to the wing plate and braced to the wing spar - then a hardwood beam as per the plan.....

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It's an interesting idea. I don't quite understand the Depron spar. If you're cladding it with 3mm and 1.5mm balsa anyway, will it be any lighter (or stronger?) than a balsa one? I would have thought a better way to lighten the spar would be to use balsa tapered to wards the tips.

Never the less, I look forward to watching and learning from your build.

Geoff

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The idea behind the Depron cored spar is for accuracy, in a traditional build the ribs ensure the spars are in the correct position - when you are using a Depron wing core plate, the plate defines the shape, the spars (more accurately half spars) are glued above and below the wing plate and each rib gets added in 4 pieces around the spar.

Will it be lighter? No it will be heavier than a simple balsa spar, but being a box structure it will be a great deal stronger and it would be the only timber spar in the wing

It would probably be perfectly fine with just the 3mm strips on the Depron spar, the problem is I dont KNOW it would be ok and apart from building different wings and testing them to destruction have no way of estimating so for the primary load bearing member in the wing I tend to over-engineer it

The weight gain in the spar will be more than offset by the weight savings in the rest of the airframe - Peter estimates 4.5lb (for the Balsa) build, I would be hoping to bring the whole thing in at about 3-3.5lb (famous last words!!)

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Posted by Simon Chaddock on 14/12/2015 12:54:03:

Dave

And don't forget Depron is much cheaper too!

It will make an interesting comparison. Watching with interest.

Just an aside but does a Depron spar with balsa flanges actually need balsa webbing as well?

In my experience Depron the full width of the spar flange provides all the shear strength required.

I wont argue with one of the Depron Gurus Simon, the only question in my mind is do I have the cahones to omit the balsa webbing!!!!! - I may compromise and just put the webbing on the spar as far out as the wheel undercarriage mounting ribs and taper it down from there

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Posted by Peter Miller on 14/12/2015 13:53:19:

This should be interesting!!

And the word that you want is Cojones. Oh I don't know, you mentioned boxes, a big box is a cajon, pronounced cahon.

Hahaha, it's nice to read my mother tongue in a British forum, even if the word relates to specific parts of the male anatomy... laugh

BTW, if anyone fancy some free Spanish lessons, I'm more than happy to help wink

Edited By AVC on 14/12/2015 14:26:26

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Mr Hopkin, Dear Dave,

I'm subscribing anyway to this build (sooo much to learn).

But if you're going the Depron way & projecting to have a 'full' build blog, I'm intended to follow you by trying to build a foamie Ballerina.

As it would be my first ever build, I would need quite a bit of support... even knowing that it should be 'cheaper' to crash.

The only point is I cannot obtain the RCME December magazine in Belgium (no distribution agent here), so does anyone could mail me the plans as .pdf, allowing me to print them at a local print store?

Thank you in advance for your assistance

Chris

Brussels, Belgium

 

ps: ... Y espero que esto no  tiene mala pinta...

Edited By McG 6969 on 14/12/2015 19:00:21

Edited By McG 6969 on 14/12/2015 19:01:25

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Hi Chris

I'll do a build blog (for what its worth) of my approach the Depron Builds if it will help you, and I have no doubt there will be better builders around than me to answer any questions and help you along (so Messers Chadwick, Electriflyer, Young Mr Bennet et al take note!) but be aware that like most things in this hobby there are many other ways of using Depron in models....

I will see if I can pick up a copy of Decembers RCME for you and if I can I'll post it

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Hello Dave,

Thank you for your reply.

I've been following this forum & some build blogs since more than a year now.

So, I know a little about the Depron gurus around here (been recently following Mr Electriflier's Mosquito from the genesis).

If would be great if you can get a December issue & have it posted to Belgium (.pdf is ok also though).

Thanks again

Chris

Brussels, Belgium

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Posted by McG 6969 on 14/12/2015 18:51:51:

M

The only point is I cannot obtain the RCME December magazine in Belgium (no distribution agent here), so does anyone could mail me the plans as .pdf, allowing me to print them at a local print store?

Thank you in advance for your assistance

Chris

Brussels, Belgium

ps: ... Y espero que esto no tiene mala pinta...

Edited By McG 6969 on 14/12/2015 19:00:21

Edited By McG 6969 on 14/12/2015 19:01:25

I couldn't get a copy either and I live in the UK! I got mine sent direct from RCME so I guess you could, too. I can't remember the link now but it you message Beth Ashby I'm sure she'll help.

Geoff

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My Spanish only extends to buying bread and beer but I'm a dab hand at Google Translate, so, as some predicted, a few posts have been binned, including those who compounded the felony by quoting the offending lines....face 5

Just a reminder that the C of C makes it very clear: Use English only please. Posts made in any other language will be deleted. There are no exceptions here.

Back to Deproning, folks....smile

Pete

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@ Peter > Thank you again for mailing me your .pdf's.

@ Dave > Thank you for your proposal to send me a RCME magazine but as Peter sent me the plan drawings, I don't think I still need it (except maybe if there is also a build article included? - but then just a scan of those pages would do, I guess).

@ Geoff > Thanks also for your help, but I hope I won't need Ms Ashby's assistance for this now.

Up to the copy shop & the material list next then.

... and of course, trying to understand the plans. smile o disgust

Chris

Brussels, Belgium

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There is a build article but it's not as useful as Peter's build thread here which is far more detailed. Though it doesn't mention Peter's trousers falling down as the magazine article does It shows that you not only need trouser clips for test flights but a pair of braces too.

Geoff

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