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Change arfoil or leave it as is?? (Read 731 times)
Reply #4 - Nov 1st, 2016 at 8:35am

staubkorb   Offline
Senior Member
Stick & Tissue
Germany

Posts: 1175
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Actually, at the scale you're talking about the 'foils shown might work just fine.  It's that love affair with air and Mr. Reynolds.  At the larger scales, the Reynolds numbers start to fall into a workable range.
 

WWWoFF
Wonderful Wacky World of Free Flight
(with a bit of rc thrown in for giggles)

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Reply #3 - Oct 28th, 2016 at 12:58pm

balsafliesbetter   Offline
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Ogden utah

Posts: 85
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I was thinking of a small blow up. About 118% for about 38", no more than 48". The fully sym. top wing was the main concern. I may also go up in the foil ratio to add just a bit more thickness. Or maybe change it to a shape that is Proven. Michael Selig did a lot of low velocity airfoils. I just wouldn't know where to start. I guess some reading is in order.
As for the the floats. I was thinking of doculam and med. silkspan on top of that, just for the bottoms. It won't be an everyday flier. Just a nice once in a while hart-stopper. Smiley
It will be a while. I need to learn some more techniques and understand ff more.

David
 

Life's Too Short.. Just Build it, and Damn The Critics!
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Reply #2 - Oct 26th, 2016 at 1:22pm

Sky9pilot   Offline
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Ditto what Pete said! Very interesting plan and model!
Tom
 

If God is your Co-pilot...switch seats...
Your attitude will determine your altitude!- John Maxwell
And ye shall know the truth, and the truth shall set you free. Jn 8:32
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Reply #1 - Oct 26th, 2016 at 8:07am

staubkorb   Offline
Senior Member
Stick & Tissue
Germany

Posts: 1175
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I had to download the plan from OZ to get a good look at what is there (photo is a bit too small for my eyes).  VERY "busy" plan, and a nice subject!

Are you planning to build it to the full size (32" span)?  If so it "should" be OK as it is, tho it WILL be a bit heavy due to the floats (careful wood selection paramount here) and the model was "designed" (and flown?) in 1993.  The airfoil of the top wing is nearly symmetrical and the lower one semi-symmetrical.  Thin airfoils are actually work better at "our" scales (much less drag).  I'd be tempted to change the upper wing 'foil to use the same as the bottom wing, but a spar re-positioning would be necessary.  The leading edge is a non-issue.

Weight can be saved in the floats by hollowing out the formers behind the step.  Will you be modifying them with clear acetate "wheels" for ROG/ landing?
 

WWWoFF
Wonderful Wacky World of Free Flight
(with a bit of rc thrown in for giggles)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
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Oct 25th, 2016 at 6:42pm

balsafliesbetter   Offline
Junior Member
Ogden utah

Posts: 85
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I'm just finishing up on my Parasol 25 incher, I got my next build sitting in the box on my work bench and I'm already planning out my 3rd.

I'm not new to building flying models, but I haven't touched FF since the 80s.. until my American Eaglet.
My question is if I should change the airfoil on the Gloster I plan to build soon. I really like the slow flying, ballet look of FF and I was looking at the thinner, more symmetrical shape of the Glosters wing. There is a lot of lift generated on the model from the fuse and 2 huge floats, but that sharp entry of the leading edge concerns me.. a little. I not that experienced in the FF designs, so I don't know how much it will effect something this light. Heck, I've had paper planes that flew unbelievable. I just wanted some opinions and what you guys think. Please don't be offended if I go in a different direction than what I'm suggested. After all, isn't that why we build our planes? To be out of the box, change from the design and see the results from our many mistakes, and once in great while, our improvements? Either way, I would love to hear from folks more experienced than I.

David

http://www.outerzone.co.uk/plan_details.asp?ID=4662
« Last Edit: Oct 25th, 2016 at 8:26pm by balsafliesbetter »  

4662_001.jpg (58 KB | 28 )
4662_001.jpg

Life's Too Short.. Just Build it, and Damn The Critics!
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