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Author Topic: Some basic questions  (Read 391 times)
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Johnpowers
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« on: May 15, 2018, 03:49:24 PM »

Hi everyone.
I’m new to gliders. I was flying ff rubber for awhile, but had to take a year off.
I wanted to get back to flying, but I don’t have the building time I had in the past, hence the attraction of gliders.
I built one called the Sandpiper that I found on you tube and flew it last week at our club field. I thought it might be fun, but it was much more than I expected: I was able to get dozens of flights and learned a little about trimming. I have a lot to learn.
I have read most of the posts here an I took lots of notes.
I have some basic questions so I’ll just start with one.
Can a designed hand launched glider function as a catapult launched glider as well?
I have seen in this forum that Flicka can be catapult launched and l bought a Campbell kit (Streaky) that can be either.
I’m not sure what modifications would need to be made. I’m not even sure about the launch slot or hook or where it should be located, etc.
I would appreciate any help on the subject.

Thanks,
john
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NormF
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« Reply #1 on: May 15, 2018, 04:22:23 PM »

Hi John
Most HLG's readily convert to CLG. The basic conversion is to add a hook on the fuselage at the leading edge of the wing. The fuselage needs to be extended about an inch so you have something to hold. A good reference is http://www.amaglider.com/ . A typical conversion is shown on the Vartanian plan, also a good plane to start with. Further down there are instructions on building and flying a CLG by Stan Buddenbohm. For a state of the art CLG, have a look at the StrayCat plan, but at this point I would stick with the simple models. At the top of the AMA Glider page is a reference to Stan's catalog. A Scout CLG is an excellent kit and flier. Buy several or use it as a pattern for making more because you will lose it!
Norm
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ffkiwi
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« Reply #2 on: May 15, 2018, 06:09:13 PM »

I have tried this in the past-and whilst a HLG can be fine as a catapult model-and vice versa-you can't combine the two-it simply doesn't work-the trim settings required are different enough between the two launch modes so that the necessary compromise to get the thing to fly as either results in an indifferent catapult model and an equally bad HLG. There is nothing wrong however in building two of the same design and setting one up as an HLG and the other as a CLG. There may be some aerodynamic layout that works both as a CLG and a HLG in the same airframe-but I don't think we've stumbled across it yet.....though the folding swept wing arrangement might offer an avenue for experimentation-but even there you'd probably have to use the wing folded mode for catapult and  the open wing mode for HLG....

 ChrisM
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OZPAF
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« Reply #3 on: May 15, 2018, 08:45:11 PM »

The basic geometry will work for both but as FFKIWI  mentions trim settings are different in extent if not in position. The higher the launch speed the finer the adjustments that will be required to trim for the climb

In fact when trimming it is best to standardise your pull on that particular catapult and trim the glider to match. The trim for a soft pull will need larger trim adjustments than a hard pull.

On adapting one of my old HLG's I added a hook at the nose - actually just another shaped piece of spruce, and it works well. It adds to the nose weight and is quite strong.

Add a hook and give it a go.

John
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Johnpowers
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« Reply #4 on: May 15, 2018, 09:13:01 PM »

Thanks for the information. The Streaky kit said to just add an inch to the fuselage. I have the glider book by John Kaufman and I thought I would build his glider and see if it works as a catapult.
I’m sure that there are lots of catapult glider plans from which to choose. I’m new to all of this so all this helps.
I think what appeals to me is the seeming simplicity of the glider and yet the complexity and challenge of construction, launching, and trimming.
When I flew rubber, I would fly, return to base, make adjustments, wind, and then return to the field to fly. When I flew my glider, I would just make a minor adjustment and fly again. There is something satisfying about that.
Thanks again for the advice

John
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