U2 Glider Conversion Scratch Build Questions - RC Groups
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Feb 06, 2002, 12:16 AM
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U2 Glider Conversion Scratch Build Questions

After reading the Ezone article on the conversion of the Lanier U2 free-flight glider to RC the wheels started turning in my head....

I have been wanting to try sailplanes simply because of the relax factor of soaring around several hundred feet up for 30 mins or more. As a big fan of the Lockheed U2 and the photo missions it under took, I would like to build a low-cost air-born photo or video sailplane modeled after this plane.

The ezone article conversion came out with a 6.4 Sq In wing load using what appeared to be a Zagi 400 power system with standard size (2 servos) radio gear.

The specs are:
Span: 74"
Length: 56"
Wing Area: 4.37 Sq Ft (629 Sq In)
Weight: 16 to 24 Oz (From Lanier)

What would be an acceptable AUW (with camera/wireless payload) and wing loading to produce glider like performance and possibly soar if conditions are right?

What wing loading makes a good floater?

What is the formula to detrumine how much torque from a servo you need to move a control surface? I would like to go as light and as cheap as I can, so would HS-81's be ok?

I just want it to be able to climb to altitude and be able to SLOWLY cruise around and take pictures. No loops, no rolls, just RELAX!

I have only flown aileron and delta mixing type aircraft. Should I bother to put a single servo on the wings to control banking better? I use a JR 8103. Will soom kind of mixing be required if I use only rudder/elevator/throttle?

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Feb 07, 2002, 04:51 PM
Lifes 2 short, go sloping
If you put in 3 HS 81's and standard gear the wing load would be right at 7oz per sq ft. That is pretty good for a glider, but I have a scratch built 8ft fox with a 10 oz wing load and it floats like a dream.
You calculate wing load by dividing weight by sq ft wing area. I would put in 2 degrees of dihaderal in the wing and if the CG is back to far I would cut the fuselage behind the wing it help balance it.

I mainly slope but this looks like a great plane to convert and if I didn't already have 10 planes I would buy it (I might anyway?). the 4.5ft planes they also sell might be fun for 5 bucks.
Feb 07, 2002, 05:20 PM
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Thanks Vinnya42, I thought the HS-81's would work out ok. I prob will use a single servo to add aileron control for those banked aerial shots

I am going to set up everything in MotorCalc and explore my options on power and batteries to try and get 15 min runs at altitude.

When you talk about adding 2 degrees of dihaderal, I assume you mean put an angled shim in-between the wing halfs when I join them? Sounds pretty basic. I should be able to dial in the CG considering I will prob have the camera pod near the front of the plane. I am thinking that I will come in under the review weight, if I use HS-81's and my Jr 610M rx, not including aerial sensor gear.

I was thinking of using a speed 400 motor and an esc with a brake along with a folding cam prop. Would I benifit greatly by using a brake and folding prop?

To Keep the weight down, I prob will not cover it with UltraCoat Plus this time like I have done on my past foam planes. Prob will just do some simple trim work to increase my sense of it's orientation at altitude. Maybe a NASA logo and a few stripes

Feb 11, 2002, 04:07 PM
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Visit www.eam.net look in their "skunkworks" section for the Dragon Lady. I think you'll like it!
Feb 11, 2002, 09:14 PM
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Roger_One, I looked at EAM Dragonlady last fall, but it seems they are still months away from shipping even the eval kits. It sure looks sweet though. I'm not sure I want that much speed....

Feb 11, 2002, 09:25 PM
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Thanks for all of the input, but I think I am going to scratch the idea of this plane for practicality reasons.... It will be to light to fly in most of the windy days we have here and will require a large field to really enjoy, which means I will prob only fly it twice a month...not worth it for me.

Feb 14, 2002, 08:10 AM
Registered User
Where did you find that article on the u2 modification?
Do you have the Link?