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Old Oct 10, 2008, 05:13 AM
gpw
“There’s no place like Foam”
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United States, LA, New Orleans
Joined Jul 2002
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A gentle S shaped airfoil 4% seems to be the best airfoil for these planes ...
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Old Oct 10, 2008, 09:57 AM
SILENCE!!
Pathfinder834's Avatar
Costa Mesa, CA
Joined May 2006
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Forgive me guys. I have not built this plane yet and wanted a nice set of plans for myself. So I drew it up per the French plans dimensions. I will remove the plans that I have posted. There was no mention of mods in the previous posts, so I thought it was good to go. It's kind of hard to see your profile Goldguy. Do you have more detail on your airfoil?

Rick
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Old Oct 10, 2008, 01:39 PM
flyin' fool
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Vancouver Island, Canada
Joined Jul 2003
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The plan from the French site will work OK for indoor, but it tucked badly at high speed. I guess they don't have decent French Curves in France. There are some good pictures of the airfoil and plans at..... http://www.flyelectric.ukgateway.net...r.htm#drenalyn , all in English too.

Check out all the other great design to be found there, plus lots of very good info on 'E' flight.
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Old Oct 10, 2008, 02:34 PM
Out the Window
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United States, FL, Alachua
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Quote:
Originally Posted by goldguy
I guess they don't have decent French Curves in France.
Now that is funny!
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Old Oct 10, 2008, 03:07 PM
SILENCE!!
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Costa Mesa, CA
Joined May 2006
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I much prefer American curves. On that note, the airfoil on that site is almost exactly the same as the one I drew/copied. The only difference that I see is the incidence of the wing related to the thrust line. Is that what it comes down to? Is that the "line" you were referring to? What else am I missing?

Rick
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Old Oct 10, 2008, 03:59 PM
a little kid at heart
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Poulsbo, Wa
Joined Sep 2004
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I believe the GWS bug has that same undercambered airfoil. http://www.gws.com.tw/english/product/airfly/eb.htm

I had one and the flight characteristics were ok. I always thought that a flat plate would fly better as the cambered part didnt allow airflow over the elevons evenly. ie the "down" elevons got more air and the "up" elevons got less (as the prop wash is deflected by the camber)...does this fly different?

Bill
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Old Oct 10, 2008, 04:01 PM
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United Kingdom, Bracknell
Joined Nov 2000
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Quote:
Originally Posted by goldguy
There are some good pictures of the airfoil and plans at..... http://www.flyelectric.ukgateway.net...r.htm#drenalyn , all in English too.

Check out all the other great design to be found there, plus lots of very good info on 'E' flight.
I just mentioned that site a few posts back. I used to fly with the owner.
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Old Oct 10, 2008, 08:45 PM
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Eugene, OR
Joined Dec 2006
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thanks for that link again, I didn't see the tiled plan at first. I think the 400mm (15inch) wingspan version will be about right for the park 250?
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Old Oct 10, 2008, 08:58 PM
flyin' fool
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Vancouver Island, Canada
Joined Jul 2003
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Quote:
Originally Posted by Pathfinder834
I much prefer American curves. On that note, the airfoil on that site is almost exactly the same as the one I drew/copied. The only difference that I see is the incidence of the wing related to the thrust line. Is that what it comes down to? Is that the "line" you were referring to? What else am I missing?

Rick

Yup, that's the line I'm talking about.

As concerns how effective the elevons are when using an undercambered wing, I've never experience that problem with about a dozen Drenalyns I have build, in fact, the Drenalyn has the edge on the flattie Pizza Box Flyer and I've build lots of those too. You have to consider the boundary layer, as the air sticks to the surface, the CG placement and the amount of throw, differential preferable. Many high performance gliders use undercambered airfoils with reflex and those designers know more about aerodynamics than I do.

Maybe the GWS pizza thingie just need fine tuning.
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Old Oct 10, 2008, 10:29 PM
SILENCE!!
Pathfinder834's Avatar
Costa Mesa, CA
Joined May 2006
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Quote:
Originally Posted by goldguy
Yup, that's the line I'm talking about.
Super! Thanks for that, Goldguy. It makes a ton of sense. Once I clear the LF Bug and other projects of my bench I'll have to attack this one.

Rick
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Old Oct 11, 2008, 02:24 AM
Registered User
USA, CA, San Carlos
Joined Nov 2007
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Here's me flying my Drenalyn in my garage

http://abolfazl.me/Jeff/100_2332.MOV

- Jeff
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Old Oct 12, 2008, 03:24 PM
Curiouser and curiouser
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Rochester, NY, USA
Joined Oct 2005
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Jeff:
I like that tail touch on the table, you did near the end and I ESPECIALLY like the SPLAT sound on landing.
What size is it?
What weight?
What parts?
Etc?
It seems to have a rudder - is that correnct?

Walt
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Old Oct 12, 2008, 09:18 PM
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Eugene, OR
Joined Dec 2006
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mines done

Finished mine today, fun plane. My thanks to whomever designed it. Just what I was looking for, flies very very slow, good for my cul de sac flying. I like my micro sumo for that as well, but this is good for something less frantic. Just under 4oz with park 250 and 2s 250 14gm lipo. 400mm wingspan. Custom bug style landing gear, great ground handling and shooting touch goes is great.

I wish it had a little more control authority in the elevons, it hesitates to roll. Helps to use a bit of rudder to roll it over. I think the cheap hobbycity 3.5gm servos don't look like they have much travel, nor do they center very well. Get it trimmed and it flies very well hands off, but keeps going out of trim and I just gave up, they seem to find a new center every now and then. Its not a big deal but you always have to fly it this way. May look into different servos. Hopefully get some pics or video up soon...
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Old Oct 12, 2008, 09:40 PM
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USA, CA, San Carlos
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wjbite,

It's a 20" WS out of PBIII. Blue wonder 12t 24g, 12 amp esc, gws 8x4 DD prop, hextronik 5g servos, ar6000 RX, 2 cell 500/800 or 3 cell 610 for outdoor flying. It's about 6.5 oz AUW. I just scrapped that one and used the same equipment to put on a 20" WS 5mm EPP version, and this one weighs in at 5.5 oz with a 2 cell 500. It flies even better in the garage now . Yep, it has a rudder. It's essential to indoor flying and maneuverability.

- Jeff
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Old Oct 13, 2008, 06:55 AM
flyin' fool
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Vancouver Island, Canada
Joined Jul 2003
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Nice to see this thread pickin' up some steam. It's a great design and is deserving of more attention.

I'm not too sure where the design came from, but the very first version of this wing platform I saw fly was the 'lil' Moe' and that goes way back when.

doser: Try moving the CG back and go with more throws. All mine rolled instantly without rudder input.
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Last edited by goldguy; Dec 15, 2008 at 02:41 PM.
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