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Old Jul 12, 2012, 07:22 AM
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epoxyearl's Avatar
United States, MD, Elkton
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Per BMatthews,I built a 5 " square balsa framework,and stretched his suggested silkspan covering across it.
I'll sand and give it a coat of dope occasionally today,then double it up tomorrow.

Since I don't intend to land in the corn,and if I do,the covering will be moot,I just want to go for the "look".

It's gonna be displayed in the Museum,withdrawn each October,to be flown in the Vintage R/C meet here in the East.-and what the heck-patches are authentic anyway,right ?
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Old Jul 12, 2012, 08:18 AM
AndyKunz's Avatar
Illinois
Joined Sep 2001
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I think silk or silkspan would be the ticket, with a traditional dope finish.

I can't wait to hear how you like the cable drive on the prop.

Andy
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Old Jul 12, 2012, 08:43 AM
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United States, PA, Beaver
Joined Sep 2001
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Quote:
Originally Posted by RCROBBY View Post
I see you are in Coraopolis, not too far from me. Where do you fly?
I fly at the ARCS (gparcs.com) We're having a fly-in in Sept (the 15th). Plenty of Prizes. Come on out.

Where do you fly? I used to go to an electric Fun Fly in Rosrtaver ( I think that's where it was) The guy hosting it lived in Greensburg.
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Old Jul 12, 2012, 09:50 AM
pd1
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United States, MA, Haverhill
Joined Jun 2006
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Earl, Just my .02. The free flight guys have been using tissue over mylar for quite a while.The mylar adds a lot of strength.

I had a silly idea a while back, I covered a plane with doculam ( the only mylar I had) then scuffed it up and covered it with light weight silk.
I wanted the doculam to reduce the need for dope both for filling the balsa and the weave of the silk.

So far I have only covered the rudder with the silk but the weave of the silk filled with only a couple of coats of dope.
The doculam also added a lot of strength.

I do plan on finishing the test plane soon, but maybe you might want to try a test to see if that might work for you.
This is where I got the silk:
http://www.dharmatrading.com/html/eng/3374-AA.shtml

It's still priced well.

Paul
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Old Jul 12, 2012, 10:28 AM
Laser Cutter Guy
United States, PA, Greensburg
Joined Oct 2009
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Quote:
Originally Posted by rcav8r2 View Post
I fly at the ARCS (gparcs.com) We're having a fly-in in Sept (the 15th). Plenty of Prizes. Come on out.

Where do you fly? I used to go to an electric Fun Fly in Rosrtaver ( I think that's where it was) The guy hosting it lived in Greensburg.
I'll have to check it out. The fly-in you are talking about I believe was at Cedar Creek park. that's about 10 mins from where I live. I have been to that fly-in before. I fly out of Laurel Highlands MAC (lhmac.org)

Sorry for the de-rail Earl
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Old Jul 12, 2012, 02:29 PM
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Apology noted-not necessary....Earl.

...I'm at Warbirds over Delaware-my spirits are high.!
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Old Nov 02, 2012, 10:00 AM
Laser Cutter Guy
United States, PA, Greensburg
Joined Oct 2009
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Earl,
Ant new progress on the Sparky?
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Old Nov 02, 2012, 10:12 AM
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I've been framing the stab and rudder,in the background,while I try to decide what to do on the drive system......cable or shaft...I have a cable in hand..

It's new territory for me,so just hanging the .91 4 stroke on the nose and balancing it is attractive at present...

I don't lock in on one thing-I could use different power trains...I REALLY want to use a belt reduction with scaled size prop.

The wheels are finished-brass bushings,and 10 coats of clear poly-u.
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Old Nov 02, 2012, 10:37 AM
Laser Cutter Guy
United States, PA, Greensburg
Joined Oct 2009
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IMO, for a belt reduction, using a shaft is the only way to go. I don't see any problem hanging the engine out front either. That would make operation and adjustment very easy.
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Old Nov 02, 2012, 11:57 AM
B for Bruce
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The 'Wack, BC, Canada
Joined Oct 2002
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A "scale size" prop would most certainly be a big eye widener.... The original rubber model used a 12 inch freewheeler on a 32 inch wing span. So your 114" monster would need to use a 43 inch prop. And the chord at the max width point a little over half way out from the shaft would be around 4 inches wide....

Then you'd want to figure out how to do the folding hinges....

Of course all that would be a little more than silly. I just thought I'd toss it in for fun.

Earl, how's the weight of the model coming out? And what about the need for nose weight for balance so far?

I'm wondering if a slightly smaller and lighter engine would work out mounted up in the nose with or without a reduction and extension for at least a prop size which would sort of look like a rubber model.
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Old Nov 02, 2012, 12:09 PM
Laser Cutter Guy
United States, PA, Greensburg
Joined Oct 2009
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Quote:
Originally Posted by BMatthews View Post
A "scale size" prop would most certainly be a big eye widener.... The original rubber model used a 12 inch freewheeler on a 32 inch wing span. So your 114" monster would need to use a 43 inch prop. And the chord at the max width point a little over half way out from the shaft would be around 4 inches wide....

Then you'd want to figure out how to do the folding hinges....

Of course all that would be a little more than silly. I just thought I'd toss it in for fun.

Earl, how's the weight of the model coming out? And what about the need for nose weight for balance so far?

I'm wondering if a slightly smaller and lighter engine would work out mounted up in the nose with or without a reduction and extension for at least a prop size which would sort of look like a rubber model.
LOL, I never thought of what size a "scale" prop would be. I forgot this was a rubber plane originally. I wonder if the .91 would even fly the plane, but the AUW will give a better idea on that.
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Old Nov 02, 2012, 12:18 PM
B for Bruce
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The 'Wack, BC, Canada
Joined Oct 2002
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Oh, it'll MORE than just fly it provided Earl hasn't gone with cast lead wheels for it...

A model of this sort is largely a powered glider thanks to all that wing and relatively light structure. To give you a feel for this I've got a Roger Hammer Flamingo. A rather bulky and big model with an 84 inch span. Weight on this ready to fly is 5.5 lbs. I fly it with an old loop scavenged OS .35 and if set up for max power with the proper 10x6 prop it climbs up with a good solid 35 to 40 degree climb.

Where I'm going with my question about the weight and all is that Earl's version might just do fine with a .60 to .65 size four stroke up in the nose. Especially if it would only take an ounce or three in the tail to balance it out. The assumption here being that the weight comes in at around 7'ish to 8'ish lbs.
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Old Nov 02, 2012, 04:45 PM
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United States, MD, Elkton
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re: report#85

Wow ! I got nailed on that one!
I didn't do my multiplication on the 'scale' prop...Even with MY imagination,I don't think that'll work..

I'm not even trying to get it under 10lbs....I have a .91 in a 1/4 scale 105" Cub,and at 17lbs,it's powerful,and a floater. I'll use the same engine in Sparky,either direct drive,or with the shaft or cable.

I do,however have visions of a free-wheeling prop of a larger diameter,just to give it that 'feel'...This isn't a contest model,just a nostalgic reminder of the past..
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Old Nov 02, 2012, 06:15 PM
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Illinois
Joined Sep 2001
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We have 24 guys in our club building Sparky's for a one-design contest over the winter.

You need to post more pix!

Andy
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Old Nov 02, 2012, 06:41 PM
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United States, MD, Elkton
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...Wait-I ain't ready fer Sparky I won't start on her till late this month...Nothing has changed since the last pictures...But as soon as I get back,I'll post pix.
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