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Old Aug 26, 2006, 05:45 PM
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Ann Arbor, Michigan, United States
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great pic H-J. wow! $3000... i wish i coulda gotten one.
'you've got mail!'
enjoy
-beanie
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Old Aug 26, 2006, 05:50 PM
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ok, next step was to glue the formers into place. this goes pretty quick as well. i just marched down the fuse from BH#1 down to BH#7.
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Old Aug 26, 2006, 05:59 PM
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i was being cheap, so i used 6mm FFF for the entire build, including the sheeting. using 3mm may have saved some weight, but right now the plans are set up for 6mm sheets. to keep scale, if someone uses 3mm sheets, then the bulkheads should be enlarged by the appropriate amount.
-beanie
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Old Aug 26, 2006, 06:43 PM
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New Bern, NC
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Did the FFF work well for sheeting? Is that the new stuff or the dwindling stock of good FFF?

Im anxious to try the Green Guard as sheeting on a future build.

Paul
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Old Aug 26, 2006, 06:49 PM
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I must be different because I got some of the new "bad" fanfold and like it. It only has plastic on one side and is very pliable. Since I strip the foam and glass anyway it saves some trouble.

J
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Old Aug 26, 2006, 06:56 PM
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New Bern, NC
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So you're liking the new foam as long as you glass it?

The Green Guard is pretty pliable as well, for me it will come down to cost per bundle when I run out of my current stock of FFF and (FREE!)Green Guard.

Paul
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Old Aug 26, 2006, 07:05 PM
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i like the new FFF for the sheeting. like J said, its a little more flexible, so its great for sheeting curves without breaking. i try and save the good old stuff for the pieces that need to be a little more firm... like wings, stabilators and fins.
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Old Aug 26, 2006, 07:14 PM
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next is installing the motor mount support. it is tucked under BH#7. then the hard stick motor mount is glued in. i designed this section so that there is quite a bit of support from the motor mount support, BH#7, aft planform and the fin. it gets sandwiched in there nicely and tightly. i had no problems mounting it straight on for my mig-25, so i did the same here. i keep everything to scale... so no cheating on the fin, wings, stabilators. this is important because of the degree of sweep the mig-21 has in the stabilators. you'll need to lay the stabilators and fin in place. then put the motor in with its appropriate prop to make sure you cut the motor mount long enough such that the prop doesn't hit the swept fin or stabilators.
now on to the ailerons...
-beanie
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Old Aug 26, 2006, 08:57 PM
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ok, before the skinning is placed, i decided to install the aileron linkages. for this bird, i opted to keep her looking a little more sleek and placed the servo inside the fuse. i just used 1 servo for the ailerons... gettin' poor, need to conserve $ and resources
i used 0.055" piano wire. 90 degree bend into the aileron. then run it along the edge of the LE of the aileron. then through a plastic tube and finally another 90 degree bend upwards.
a trench is cut out for the plastic tube. the aileron LE is sanded to a wedge to allow easy movement. i drilled a hole into the aileron for the control rod to insert into. then the plastic tube is glued to the fuse planform.
-beanie
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Last edited by beanie; Aug 27, 2006 at 06:41 AM.
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Old Aug 26, 2006, 11:14 PM
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Ann Arbor, Michigan, United States
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aileron hook up. i used some commercial aileron linkages from the LHS on my first build. but, on the second version, i borrowed AC's idea of simply using heat shrink as the junction. i used a couple layers to strengthen it. i had problems with the original commercial linkages because the 0.055" piano wire was too thin for it to grip to. we'll have to see how she holds up. the second version has control surfaces with much less slop.
i used the same plastic tubing as guide rails to help prevent flexing of the control rod.
a servo holder was made from FFF as well.
-beanie
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Old Aug 26, 2006, 11:19 PM
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New Bern, NC
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What was the brand of those linkages Ben? I've needed similar stuff and had to cobble it together...I like those setups, even with the heatshrink.

Paul
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Old Aug 26, 2006, 11:24 PM
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hey paul, i think i got dubro linkages. i don't have a part number cuz i tossed it quite a while ago. the problem with the heat shrink is that it still slides around a bit. i would recommend a tiny dab of epoxy or CA to fix it in place. i still had a little slop despite that (all of my planes are kinda sloppy). but when i used AC's method on the second build, there is WAY less slop. i'm sold on his aileron linkage method as well as finishing method. i did have some concerns that over time, the metal pushrods would cut into the heat shrink and lead to failure at some point... but i'm sure, my plane won't survive that many flights for this to happen (i've got way too dumb thumbs). ie, the 25 missions needed for the b-17 crews in WWII is a statistical impossibility for me
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Old Aug 27, 2006, 12:54 AM
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Lol Ben...just keep her 3 mistakes high and you'll do fine!

The majority of my crashes come when I'm down playing in the dirt, or yanking and banking too hard.

If I could make myself fly in lazy circles, I'd have 25 flights easily. Take that approach and you'll be amazed at how long your planes will last.

Thanks for the heads up on the Dubro linkages.


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Old Aug 27, 2006, 06:46 AM
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before the sheeting is applied, i installed all the electronics. we've got the ailerons done. next is the esc and motor wiring. i fall into the group of people that lengthen the motor-esc wires as opposed to lengthening the esc-batt group. this has worked for me so far. i know others swear by the other method. despite the debate, doesn't seem like it makes all that much difference at the short extension lengths we are using.
anyway, i twist the wires, wrap them in aluminum foil and then thread them through their own holes in the bulkheads. i didn't want them rubbing up against the metal control rods running down the middle.
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Old Aug 27, 2006, 07:23 AM
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Quote:
Originally Posted by DCobra

The majority of my crashes come when I'm down playing in the dirt, or yanking and banking too hard.

Paul
EXACTLY! Just about the time you think you're Maverick, it brings you down to Earth!

J
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