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Sep 15, 2018, 02:59 PM
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Not much to report as the maiden did not go too well as it crashed!
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the right wing spar was broken in two places.
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And the U.C seriously deranged!
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It did actually fly quite well until a prop came off and of course it had to be an outboard one! The full size Albatross only had marginal 'engine out' capability so definitely not on a high powered model - it simply spun in. If I had realised what had happened I might have done better to simple cut the power but not that easy to do when you are in a tight well developed spin at low level.

It appears its 'quad' ESC's have their brake set by default so a momentary loss of power in the flight caused the motors to stop almost instantly with the result that one of the props simply spun off. Note to self - do them up a bit tighter next time!
With its super light weight construction it is not the easiest thing to repair. I might have to adopt some 'innovative' rebuild solutions.
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Sep 15, 2018, 07:45 PM
Registered User
Too bad. It might be easier to rebuild the wing from scratch.

About a third of my maiden flights result in some repairs and sometimes more or less complete rebuilds. The joys of scratch building.
Oct 03, 2018, 08:08 AM
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Thread OP
The Albatross wing is basically a stressed Depron skin monocoque that provides all the torsional rigidity with a relatively wide full depth "I" beam to resist the bending forces.
As a Depron skin break glued together is virtually as strong as the original material in shear the first step is to simply glue the wing back together using POR for the Depron and balsa cement for the spar flanges.
By the same token a balsa glue repair can resist virtually the same compression force as the original so that just leaves the need to restore its tensile capabilities.
My solution is to use a thin layer of carbon fibre tow 'flood' glued with PVA to the bare spar flange top and bottom surface.
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With just a small amount of lightweight filler the spar repair is almost invisible and it did indeed restore the wing to something like its original strength so a start could be made to rebuild the damaged U/C mountings.
Last edited by Quorneng; Oct 03, 2018 at 06:14 PM.
Oct 03, 2018, 11:18 AM
Ken Stuhr
While that does provide enuf strength (!!!), I worry that the stresscons at each end of the CFT will be the sources of any new fracture. Easy to coach from the sidelines of course.......When I do something like this, I put a VERY long taper in the CFT to a fine point at each end to reduce this concentration, especially when the foam is so weak inherently.

Great model, best of luck going fwd!!
Oct 03, 2018, 04:47 PM
Registered User
I think I would add another strip of CF tow across the corner of the aileron cut out (and another near the LE) that always seems to be a place where breaks either start or end.

Good job on the repair!


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