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Bird of Timekit build

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Old 01-05-2016, 01:56 PM
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JMCHASE
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Default Bird of Timekit build

I've built many airplanes, but I'm finding the B of T very confusing. the instructions are not up to what I am accustomed to. Looking to correspond with anyone who has built the kit. just need a few tips on the wing.
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Old 01-05-2016, 09:06 PM
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Sure, no problem. Where are you getting behind the 8-ball?

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Old 01-06-2016, 08:27 AM
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First i would say you have a beautiful sailplane...... Next i will be sending an email later in the day when i have more time to write.
John
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Old 01-06-2016, 08:37 AM
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Yes, what difficulties are you having. Please remember that the model was designed when "good" instructions consisted of a printed sheet that mostly said things like:

1: Pin spars to plan
2: Glue ribs to spars where the plans show you
3: Add top sheeting. Pay attention to sizing per the plans.
4: Remove wing from building board and add bottom sheeting
5: Glue doublers to fuselage sides. Make sure you make a left and right side.
6: Install fuselage formers in locations shown on plans. Make sure the fuselage is straight.
7: Install top and bottom sheeting.
8: Construct stabilizer, elevators, fin and rudder according to the plans. Cut the parts from the stock provided.
9: Cover with covering of your choice.
10: Install receiver, battery, and servos as shown on the plans.
11: Add weight where needed to balance at the point shown
12: Go fly and enjoy!

The plans back in the day were such that you could build from them with little need for step-by-step instructions. Since the BOT was considered an advanced design, it was assumed by all that you knew what you were doing when it came time to build one.
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Old 01-06-2016, 09:36 AM
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Been building since 67, but since Thornburg is a member of the same club as i am , i decided i would try to follow the instructions. I can build it without them but i am trying to be true to the original. I will get back with a few questions thanks
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Old 01-06-2016, 01:12 PM
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first I have the Dynaflite instruction booklet. referring to the instillation of the steel shaft in the inboard wings. the instructions call for the inner wings to have a 3.5 degree dihedral...so the metal rod needs the same. how did you approach this did you build both wings first then build in the shaft angle. seems to me if you follow the instructions and build one wing at a time you run the risk of the shaft not fitting perfectly due to the angle in the wing. and how did you build the support for the shaft between the spars.

on page 7 it shows a picture of a rib where you cut out a center section instructions 14 are a bit confusing it says to cut this piece out and glue it to the end of the innermost shear web? that makes no sense.
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Old 01-07-2016, 08:59 AM
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Originally Posted by JMCHASE View Post
first I have the Dynaflite instruction booklet. referring to the instillation of the steel shaft in the inboard wings. the instructions call for the inner wings to have a 3.5 degree dihedral...so the metal rod needs the same. how did you approach this did you build both wings first then build in the shaft angle. seems to me if you follow the instructions and build one wing at a time you run the risk of the shaft not fitting perfectly due to the angle in the wing. and how did you build the support for the shaft between the spars.
Ahhhh, understood. Actually, it's no problem, just a bit confusing with the way they described it - and a bit cumbersome. They want you to build the wing and then drill through the ribs to install the joiner tube - there's a much easier way (which is what I do with most of my "big wings": build the wing - LE, TE, top & bottom spars, ribs, bottom sheeting. Install FRONT sheer webs for ribs 1-5 and then simply dig out the area between the spars with a drill or exacto (my method). It doesn't have to be perfect. I actually remove about 95% of the wood in this section. As long as you leave rib-wood connected to the top and bottom spars you're OK. I DO drill out at the joiner rib (where the 2 wings come together) so it's a stable (and decent looking) support for the tube but nowhere else. Then just place the tube in the wing and epoxy in place. I did a quickie drawing:


Rib #1 is the joiner rib, and it's actually angled slightly (forgot to draw that in) - it actually gets drilled. #2-4 get dug out. Kinda like this - the red area below:
The green is the front sheer web. You're digging out ribs 2-4. #5 is untouched. Going back to the top pic, once the tube is in place I filled the entire green area with balsa & epoxy. It's 100% solid.

on page 7 it shows a picture of a rib where you cut out a center section instructions 14 are a bit confusing it says to cut this piece out and glue it to the end of the innermost shear web? that makes no sense.
Yeah, you're looking at step 13 - understood. The rib is cut out to fit it outside those polyhedral braces - you're actually cutting the rib in half, removing that center section entirely. I'm one of those "build it like a tank and it'll never fail" guys. I actually went one better than the instructions. What I did there was NOT install the polyhedral rib until after the inner and outer wings were joined by the braces that fits between the spars, making a single wing (left or right). Then I added an outer ply brace to that, like a sheer web, front and back. THEN I cut and fitted polyhedral rib in place, using epoxy to join them to the structure (spars-webbing, LE, TE). I remember that it took me quite awhile to think this one out too. They could definitely make their thinking a bit clearer in that section.

Gotta tell you, it's kinda fun, going back and re-thinking my thinking back then. There was a lot of "geez, how am I ever going to do this" kind of thinking with this bird. Sure is worth it though.
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Last edited by skylark-flier; 01-07-2016 at 09:07 AM.
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Old 01-08-2016, 03:19 PM
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Sorry i didnt get back to you sooner been fighting computer problems. You did an excellent job gave me a good plan on how to proceed. Another question the kit gave me a plywood rid. Much too large said to glue it to the inboard rib even the hole that was drilled in it was off? An idea what to do?
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Old 01-09-2016, 05:04 AM
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Hey, not a problem with getting back to me - ever. I'm retired, got all the time in the world.

Yeah, that's that first rib, my #1 on the first graphic. You should actually have 2 of them, one for each side.


I'm not 100% sure on this but I seem to remember that you've got a balsa #1 rib and the ply rib is glued over the balsa rib once the wing is assembled, including top sheeting. Then you just sand it all smooth and even.
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