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Old Jan 20, 2013, 03:31 AM
ulpilotrmh
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USA, FL, Tavares
Joined Sep 2010
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After all the anxiety over doing the covering of the underchambered airfoil, it turned out to be a piece 0' cake. It was just tedious. The 1/32" capstrips I added to the bottom of the ribs managed to hold the polyspan off the spars so I should have a nice smooth wing surface when it's done.
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Old Jan 22, 2013, 09:55 PM
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United States, NM, Albuquerque
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I'm enjoying your build thread. Question: would the Thermic's fuse accommodate placing the motor in the nose instead of a power pod?
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Old Jan 24, 2013, 09:38 AM
ulpilotrmh
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USA, FL, Tavares
Joined Sep 2010
315 Posts
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Originally Posted by TScott1118 View Post
I'm enjoying your build thread. Question: would the Thermic's fuse accommodate placing the motor in the nose instead of a power pod?
I started out with the intention of modifing the design so the motor would be in the nose. Long story short, that didn't work out as well as I thought. I've decided to try a different route. I have a copy of the Thermic 70 plan that is designed with a "Built Up" stick type fuselage that should be lots easier to adapt to electric power. The power pod set up was never an option for me. My intention is to alter the width of the fuse just enough to accomodate the motor and alter the T 70vertical tail to utilize the T 72 horizontal stab I have. my T 72 wing will work on the T 70 fuse as is.

Stay tuned for further developements.

Russ
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Old Jan 24, 2013, 09:48 AM
ulpilotrmh
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USA, FL, Tavares
Joined Sep 2010
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New self inflicted problem.

I covered the wing and tail surfaces with Polyspan using established practices. The wing is fine as is, but the horizontal stab is a mess. the stab is the first part I covered and I screwed up by doping it on the frame with the wrong side up. How do I get the Polyspan off without destroying the frame work? there is no problem stripping it off the ribs but how do I get it off the solid and sheeted areas? This stuff is really stuck down. I tryed soaking with dope thinner but this doesn't seem to help much.

Russ
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Old Jan 24, 2013, 06:42 PM
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Huntsville, AL
Joined Apr 2004
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Quote:
Originally Posted by ulpilotrmh View Post
New self inflicted problem.

I covered the wing and tail surfaces with Polyspan using established practices. The wing is fine as is, but the horizontal stab is a mess. the stab is the first part I covered and I screwed up by doping it on the frame with the wrong side up. How do I get the Polyspan off without destroying the frame work? there is no problem stripping it off the ribs but how do I get it off the solid and sheeted areas? This stuff is really stuck down. I tryed soaking with dope thinner but this doesn't seem to help much.

Russ
Russ,
I have REALLY enjoyed your build thread. As for the Polyspan, did you use Butyrate or Nitrate to adhere the material to the structure? I've used a lot of Polyspan on OTers and FF gliders and absolutely love it. I use Nitrate to adhere, and straight nitrate thinner has worked for me, just had to take my time. On one of my Lil' Dip towliners, I had the same problem, and ended up removing the Polyspan from the open bay areas, leaving it on the sheeted areas, and re-applying fresh PS to the whole thing. That time, slick side out. On a different model, I just used more Nitrate to fill the weave. (I didn't recognize my error until I had put 3 coats of Nitrate on the covering.) It still had some fuzzies, and was aesthetically unsatisfying, but didn't seem to affect flight.

Jim Howell
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Old Jan 31, 2013, 02:17 PM
ulpilotrmh
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USA, FL, Tavares
Joined Sep 2010
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Originally Posted by JoHowell View Post
Russ,
I have REALLY enjoyed your build thread. As for the Polyspan, did you use Butyrate or Nitrate to adhere the material to the structure? I've used a lot of Polyspan on OTers and FF gliders and absolutely love it. I use Nitrate to adhere, and straight nitrate thinner has worked for me, just had to take my time. On one of my Lil' Dip towliners, I had the same problem, and ended up removing the Polyspan from the open bay areas, leaving it on the sheeted areas, and re-applying fresh PS to the whole thing. That time, slick side out. On a different model, I just used more Nitrate to fill the weave. (I didn't recognize my error until I had put 3 coats of Nitrate on the covering.) It still had some fuzzies, and was aesthetically unsatisfying, but didn't seem to affect flight.

Jim Howell
Hey Jim,

I used Nitrate Dope. I managed to get most of the covering off and reapplied it. I put on 3 0r 4 coats of Nitrate again. I couldn't find Polycrylic in a spray can and went ahead and sprayed Krylon red over the Nitrate Dope. Huge mistake! The Krylon is heavily crazed and I'll be building a new horizontal stab if I can't get this Polyspan off without destroying the framework.

Last Friday my computer caught a virus and I just got it back from the repair shop. In the meantime I had started building the built up style fuselage for the T 72. The original plans build an extremely light weight/fragile air frame. I have added diagonal bracing and some light ply to stiffen the core structure.

Russ
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Old Feb 02, 2013, 11:46 AM
ulpilotrmh
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USA, FL, Tavares
Joined Sep 2010
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I now have all the formers and stringers installed. Next is the forward hatch. I intend to build the hatch as a solid balsa form that I will hollow to some extent. The hatch will be held in place by a couple of rare earth magnets at the front and by the wing seat at the rear. After the hatch comes the nose block and then the vertical stabilizer will be finished.
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Old Feb 03, 2013, 03:01 PM
ulpilotrmh
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USA, FL, Tavares
Joined Sep 2010
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What a PIA getting the covering off the horizontal stab. I know, I know I did it to myself by being in too much of a hurry and mixing incompatable finishes. I worked most of the morning and got all the covering off the right hand half of the stab and have started recovering, for the 3rd time.

I also discovered the T-72 horizontal stab has a wider chord than the T-70, but it's too late to correct it now. I think it'll work okay, just won't fit right. Woulda been an easy fix if I had noticed the problem sooner.

Russ
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Old Feb 04, 2013, 07:33 AM
ulpilotrmh
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Last night before I fell asleep, I had a brainstorm. I can move the horizontal stab far enough aft so that it won't protude past the leading edge of the vertical stab. I relocated the hole and slot, and sliced off the inboard trailing edge of the horizontal stab halves at 45 degrees to clear the rudder. If I'm careful, I can still use the drillpress to accurately drill the hole for the brass bushing.
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Old Feb 07, 2013, 02:38 AM
ulpilotrmh
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USA, FL, Tavares
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Don't know how this happened, but the the rudder ended up a little short and I had to make another.
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Old Feb 11, 2013, 07:18 PM
ulpilotrmh
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USA, FL, Tavares
Joined Sep 2010
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Okay, one more time with the rudder. For some reason, one of the hinge slots got itself off center in the 1/4" square leading edge and I didn't like that. I have a couple of slotting fixtures that usually put the slots on center without much trouble. For the third, and hopefully last time, I built the rudder with a laminated leading edge as well as the trailing edge. I sandwiched 1/32" x 1/4" balsa between two 1/8" x 1/4" pieces, leaving out the 1/32" sheet where the hinges will go. This worked out perfectly and I think I will do this from now on.

Speaking of hinges, how do you guys glue them in without getting glue in the hinges?
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Old Feb 11, 2013, 09:39 PM
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Speaking of hinges, how do you guys glue them in without getting glue in the hinges?

What kind of hinges are you using?
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Old Feb 12, 2013, 12:33 PM
ulpilotrmh
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USA, FL, Tavares
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Originally Posted by TScott1118 View Post
Speaking of hinges, how do you guys glue them in without getting glue in the hinges?

What kind of hinges are you using?
I'm using Robart hinges, the ones with the non removable pins.

I have some Sig hinges but think they're too stiff.

Russ
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Old Feb 12, 2013, 05:01 PM
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Originally Posted by ulpilotrmh View Post
I'm using Robart hinges, the ones with the non removable pins.

I have some Sig hinges but think they're too stiff.

Russ
Well then I can't help you. I use the CA hinges.
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Old Feb 12, 2013, 06:52 PM
ulpilotrmh
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USA, FL, Tavares
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Originally Posted by TScott1118 View Post
Well then I can't help you. I use the CA hinges.
That's okay. I know there are guys out there who do use them, or at least used to use them. Maybe someone will answer the question.

Actually I'm thinking of removing the hinge pins and assembling the hinge halves in the fin and rudder, then connecting all the hinge halves with one long pin thru all the hinges. This is what I'll do unless someone can indicate how I can use the hinges as is.

Russ
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