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May 12, 2015, 08:01 AM
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Build Log

Another pulsar (3.6m FH V-Tail)


I liked my original 3.6 m REF for its size.
I love 3.2 m FH for its handling and been flying it all the time.
This time it will be 3.6m FH V-Tail.
Well not quite a V-Tail. In name only. Plus it will be full flying tail.
Got parts for the plane from various RCG members. Some are totaled, some need work. Some will be donors of organs.
I finished making the gimball which will hold both feathers at same plane at all times and rotate whole assembly in yaw and pitch.
Tail feathers are made out of wing tips. Here is first issue. They are parts of the wing so they're profiled and even got some camber. I might have an issue with tail which wants to lift. And how is it going to behave when speed changes? They will have to be recovered, but i didn't pick the color yet.
Boom is out of older pulsar. It has a mounting plate at the end, which actually will help me to attach gimball. Stabilizer v-mount had to be removed. It wasn't easy. Original owner had carbon tow wrapped around it and epoxied and ca'd to boom.
Last edited by robusp; May 12, 2015 at 02:19 PM.
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May 12, 2015, 08:14 AM
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Tail feathers next to original stabilizer.
May 13, 2015, 12:12 AM
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That's what I was working on for last few days.
Boom modified to accept standard or my tail.
All parts for gimbal are ready.
May 13, 2015, 12:14 AM
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All done with exception of blind nuts to hold feathers .
May 13, 2015, 12:18 AM
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Doesn't look bad at all.
It might be awhile before I try it.
Jun 03, 2015, 08:23 PM
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Well, this design didn't make the cut.
It might of work on a plane with max speed of 5mph and no wind.
All this force from feather against pivot point on bottom could spell disaster.

I went through few more ideas and changes before I settled on this one.
Similar to original yaw base with exit for pitch cable trough center hub.
Everything made out of carbon fiber, but thinner than first model.
Feather have thin brass tubing epoxied inside carbon spar. Bottoms of feathers finished with thin carbon plate (0.3mm)
Both feather move simultaneously for pitch. I wish I had better idea how to do the linkage. I don't like it exposed as it is, but I would like to prove the concept first.
I might even try it on cheap plane before any more work.

Rob
Last edited by robusp; Jun 29, 2015 at 09:38 PM.
Jun 14, 2015, 11:54 AM
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I have little progress. Work travel and nice weather when I'm home don't help.
Tail and boom are ready. Servos are installed. they're shown in post #5.
Wing tips needed little work to line up correctly with center section. Got that.
Center section starts to look like, well center section. Still missing ribs and part of d-box. Got them made, but they need little tlc before I glue them in.
Spar was drilled for two 5mm cf tubing about 7 inches long and epoxied in.
There is also carbon strip 1.5x7x10mm in front of spar.
Later when it got all set I wrapped kevlar thread around the whole exposed area.
Bottom of wing had some balsa missing and carbon back spar was broken.
I made strips of balsa to match original thickness and I spliced carbon spar with 2 in overlap on each end.
Because it a sandwich of balsa, hinge, carbon and balsa its really hard to tell this was broken.
Last edited by robusp; Jun 20, 2015 at 12:32 PM. Reason: spar connection, back spar
Jun 14, 2015, 08:49 PM
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Here are ribs.
One extra of each.
Next step is to cap them with carbon strips.
Jun 14, 2015, 10:30 PM
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That's it for tonight.
Ribs are in.
Jun 19, 2015, 09:09 AM
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D-Box is done. I used piece from the wing tip. It fits right in between existing cloth.
It does look little darker, that's because there is layer of carbon cloth under it.
Ribs right at the joint are made out of 15mm balsa.
Last edited by robusp; Jun 19, 2015 at 09:18 AM.
Jun 20, 2015, 12:24 AM
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New servo boxes made. Old covering removed and cleaned up. (ailerons later)
Wiper on left side made out of thinner cf than original.(0.13mm - 0.26) Have to save weight anywhere I can.
Also found out left side is 2mm longer than right. Wish it was the other way around.
Jun 20, 2015, 11:23 AM
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Started covering.
Not bad for a rookie. This is my first covering job.
I also checked how bad is my center section out of balance. Needed 13g on right side.
I thought it will be more.
Jun 21, 2015, 08:35 PM
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Both ailerons are stripped, wiring harness done, linkages done.
Deans 6-pin from center section to the fuse. 3-pin epoxied in ends of center section and wing tips. Light drinking straws to cover wiring which is made out of 32ga wire.
Linkages are z bend wire soldered to threaded insert for Hayes plastic clevises.
Have to make horns out of carbon stock.
Servos on slow boat from Japan.
I might just start working on wing tips while waiting.
Covering is Ultracote light transparent white.
Always wanted to try it.
Jun 22, 2015, 02:19 AM
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Center section is covered.
Second pic shows fixed d box.

I didn't realize how close I got to running out of covering.
If I cut a quarter of an inch more material for top I would not have enough for bottom and ailerons.

Hope there is enough left to do tail.
Wing tips are staying red.
Jun 22, 2015, 08:33 PM
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Oh boy, more work.
Got another 3.6m coming.
Damaged, but not as bad as the one I'm already working on.
It'll need covering more than anything.
Tomorrow I start making horns for all ailerons, flaps and ruder.


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