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General control line discussion => Open Forum => Topic started by: Pat Johnston on January 22, 2025, 04:42:24 PM

Title: New QED 502
Post by: Pat Johnston on January 22, 2025, 04:42:24 PM
I got kind of excited and made up a QED 502.  This is relatively similar to my QED design article published in the October 1998 MA edition. I made all the current updates including the "+P" airfoil, and new construction techniques.  I flew the heck out of my original QED.  It was a great flying plane and really fun to see the reaction of its presence.  This one is no "lawn dart".  The fuselage is 6" deep just in front of the canopy so has some serious side area.  With a Badass 2814-870kv, swinging an 11-5.5" prop, the results are potent.  I'll attach the PDF's for your viewing pleasure.  Feel free to ask about details.
Pat Johnston
502 Design Studio
Idaho Skunk Works
P.S. I also just designed a Gee Bee R2-502
Title: Re: New QED 502
Post by: Shorts,David on January 22, 2025, 06:11:57 PM
Hi Pat, have any photos of your finished model? I assume you are cutting this as a kit or short kit?
Title: Re: New QED 502
Post by: Pat Johnston on January 22, 2025, 06:30:39 PM
I can find a photo of the old QED if you like. Kit price should be $225.
Pat
Title: Re: New QED 502
Post by: Gerald Arana on January 22, 2025, 07:42:50 PM
I got kind of excited and made up a QED 502.  This is relatively similar to my QED design article published in the October 1998 MA edition. I made all the current updates including the "+P" airfoil, and new construction techniques.  I flew the heck out of my original QED.  It was a great flying plane and really fun to see the reaction of its presence.  This one is no "lawn dart".  The fuselage is 6" deep just in front of the canopy so has some serious side area.  With a Badass 2814-870kv, swinging an 11-5.5" prop, the results are potent.  I'll attach the PDF's for your viewing pleasure.  Feel free to ask about details.
Pat Johnston
502 Design Studio
Idaho Skunk Works
P.S. I also just designed a Gee Bee R2-502


Hi Pat

I didn't see any dihedral on the plan. Did you give it some diehedral?

Thank you, Jerry

PS: This is one of the planes that i was interested in when I got back into CL back in the '90's and the one that I was looking at has diehedral. Cheers
Title: Re: New QED 502
Post by: Crist Rigotti on January 22, 2025, 09:37:32 PM
Very nice Pat!
Title: Re: New QED 502
Post by: Dave Hull on January 22, 2025, 11:47:53 PM
Jerry,

The plan has a note that says "1 Inch dihedral per panel."

Dave
Title: Re: New QED 502
Post by: Gerald Arana on January 23, 2025, 06:43:41 AM
Jerry,

The plan has a note that says "1 Inch dihedral per panel."

Dave

Perfect! Thanks Dave.

Jerry
Title: Re: New QED 502
Post by: Pat Johnston on January 27, 2025, 08:01:05 PM
One inch of dihedral for sure. With the wing in close to the correct position, the dihedral makes both wingtips fly level. I really liked the way the original flew, and it had an impressive presence.
Pat
Title: Re: New QED 502
Post by: Dennis Moritz on February 11, 2025, 05:26:30 AM
What foam do you use? How thick? Where do you buy? Home Depot? Does the foam core create vibration issues when used with IC? Is the sandwich more rigid then balsa?
Title: Re: New QED 502
Post by: Pat Johnston on February 14, 2025, 08:47:57 PM
The foam comes from Home Depot or Lowe’s. The overall result seems to be a relatively stiff and very light fuselage.  Haven’t noticed any vibration issues.
Pat
Title: Re: New QED 502
Post by: Ken Culbertson on February 15, 2025, 08:23:58 AM
Pat, is there a thread where your airfoil is discussed?  I used that airfoil in the 60's through the late 70's on my most successful planes but I had no idea why.  It was just easier to cut the ribs and sheet the wings.  I have been watching Crist Rigotti's Agenda series using your airfoil and noticing how they flew like my earlier designs.  I am more interested in the "why" now then I was then.

Ken