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Need advice on a Cleveland Senior Albatross

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Old 01-23-2018, 07:28 AM
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smperry
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Default Need advice on a Cleveland Senior Albatross

Always had a thing for gull wing sailplanes. I picked up a kit of a Cleveland Senior Albatross recently. I also bought a set of plans for the model. I'm old school enough that cutting parts by hand doesn't phase me, however the light weight structure of this old tow line glider is giving me some pause for thought.
I flew sailplanes for a few years several decades ago. I started with a Gentle Lady and then went to a Pierce Paragon. We would launch with either a Hi Start or a winch. Loads of fun, I even got as far as my LSF 1 hour flight.
There is no way that the Senior Albatross is going to survive either a Hi Start or a winch launch. The structure is primarily 1/16 balsa, far more delicate than what you find in a 3 meter sailplane today. As much as I'd like to build this model as a pure sailplane, the only option I see is to add an electric motor and folding prop. I was hoping for some good advice on a prop/motor/esc for this model. I'm looking for something that will fly it around in gentle climbing circles, anything more would likely rip the wings off. No idea the final weight other than it will be much lighter than
the 10' span might suggest. I'm sure there are many better modern designs, but the old style build is the attraction to me for this one, I just need a power system that will get it up a hundred feet or so.
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Old 02-14-2018, 09:43 AM
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To fly it in any manner with RC you will need to pretty well re-design the structure to beef things up. For starters you will need to modify the wings for a tried and true spar setup that will handle the flight loads that can be produced when we pull back on the elevator. And by the time you do that it will be able to tolerate a hi start. I'm thinking upper and lower caps of 1/8 x 3/8 spruce that are webbed together to form a proper I beam. You can also add either D tube sheeting to the leading edge or use a set of turbulator spars to aid with holding the covering to the airfoil shape more closely. And since free flight models did not need to fly upwind to return to their launch position you may want to consider a switch to an airfoil that has a little more speed potential. You don't need to turn it into a slope racer. But there's other options for an airfoil which will float well but can still kick up its tail and scoot a bit better.

The fuselage really does not need a whole lot of change other than materials and some additions. The stringers should be changed from the likely 1/16 square to 3/32 x 3/16 spruce or bass. And I'd likely re-cut the keel pieces that form the half shell keels from 1/16 plywood. And internally before I added all the stringers I'd look at if it's possible to add in an arrangement of diagonals to aid with reducing the ability of the fuselage to twist. Think of the diagonal lattice seen on lift cranes with the iron truss work and how to make a nose to tail arrangement of W's like this in the Albatross fuselage. It would increase the torsional stiffness by a lot if you can do this.

The wing mount will be the area that needs a lot of improvement. I assume that you'll want two piece plug on wings. I have not seen the original plans but it likely has a plywood tongue arrangement. You'll want to switch that to something like carbon rods in tubes that are in the wing roots. And the carbon rods will need to be installed in strong plywood boxes at the required dihedral angle.

There's a lot of other things that will become obvious as you work through adapting it to fly well as an RC model. But if you can start with some of these options the rest should suggest the changes that you'll need.
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Old 02-14-2018, 11:08 AM
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Thanks for the advice. Many of the issues you mentioned had occurred to me and I appreciate hearing solutions to them. I also bought a plan and parts layout from Cleveland. No way am I going to use the original kit as the wood is likely older than I am. Cutting my own parts will make it much easier to incorporate the mods you suggested. This will be a long term project and as much an exercise in nostalgia as it is an attempt to produce a model.
Thanks again
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Old 02-15-2018, 01:05 AM
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You might want to try a search on the Albatross name over at "that other model site" RC Groups. There's a really good build thread from a couple of years ago by someone that built one.

The big discovery was that the gull wing does not respond well to rudder control. He ended up fitting it with ailerons. Something you should plan on right up front. Plus by fitting ailerons you can reduce the center line dihedral angle so the outer panels have a slight droop like the full size classic gliders had and not lose anything.
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