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Old Jan 21, 2008, 10:10 AM
Checking CG is for NERDS!
Smokescreen38's Avatar
Joined Jun 2005
5,347 Posts
Quote:
Originally Posted by AIR SALLY
if you don't balance the stab and you get flutter ..... the stab will snap off....and you'll crash .you did 'nt say that you reinforced the tail fairings ? that MUST be done also . just regluing the bushing was a start ..now you need to glass the fairing or apply 1/64 ply to the fairings.as show in the up grade thread..or the way i showed in the pic's .but now that you glued the bushings in you'll have to do it another way as decribed above.good luck
Yeah... definitely going to reinforce the fairings too... I didn't forget but I do appreciate the advice!!

So does balance them reduce the liklihood of flutter or just reduce the chance that it will be fatal? They'll flutter even with stock powered planes on 3s??
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Old Jan 21, 2008, 01:50 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
21,272 Posts
yes stock set ups will flutter ...what is the fear ...put the stab in the bushing ,and you will see the back drop.put a penny or 2 washers in a slit that you cut into the stabslip in the weight and glue with 5 min epoxy. done it does'nt have to be perfect ,a penny will help a bunch. flutter will/can strip gears in servos and the twisting momentjust snaps off the fairings.
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Old Jan 21, 2008, 02:18 PM
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Formerly Denver. Now West Bend, WI
Joined Dec 2005
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I'm running the stock power system and did the taileron strenthening mods. I didn't balance the tailerons though. I haven't noticed any flutter at all with mine (6 flights so far). I'm using HS-65MGs though... they're pretty tough servos.
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Old Jan 21, 2008, 02:38 PM
Checking CG is for NERDS!
Smokescreen38's Avatar
Joined Jun 2005
5,347 Posts
Quote:
Originally Posted by AIR SALLY
yes stock set ups will flutter ...what is the fear ...put the stab in the bushing ,and you will see the back drop.put a penny or 2 washers in a slit that you cut into the stabslip in the weight and glue with 5 min epoxy. done it does'nt have to be perfect ,a penny will help a bunch. flutter will/can strip gears in servos and the twisting momentjust snaps off the fairings.
Oh... that's easy enough.

Thanks!

BTW, I am using HS-55s...they fit the pre-moulded slots in the fuselage perfectly. Assuming that the stabs don't flutter, they're up to the task, right?
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Old Jan 21, 2008, 02:51 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
21,272 Posts
well they should ...i'm using $3.00 servo's from Hobby City and i have over 500 watts ...110-115 mph no proplems yet i would like to up grade to stronger linkage like C/N did on his.but i have already ground flat spots on the axles for the stab so the linkage wont slip.the mod he did requires the flats to be on the other side of axle ...i did not want to grind both sides
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Old Jan 21, 2008, 11:40 PM
CARL T
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United States, OR, Grants Pass
Joined Dec 2005
395 Posts
If anyone is looking for the right size wire to fit the tail bushings, I searched and searched. Finally I found a wire coat hanger that is .090 diameter. Cut a piece,straightened it, cleaned it with 400 sand paper, cut it to length and used it till "ALL" tail work was done. You can install AirSally's extra bearings on the wire and get perfect alignment when gluing them in.
I cut a V where the brass bushings are then filled the V with Epoxy/micro balloons. That locks them in solid. See drawing.
When adding weight to balance the stabs, keep it as far foward (ahead of the pivot rod) as possible. The further foward the less weight you have to put in. Mine took 4-1/2 grams each to balance. I cut down those 1/4 ounce tire weights from the tire shop. The ones that come in a strip that is cut at 1/4 ounce points.
Carl
PS: having trouble attaching drawing.
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Last edited by Carl T; Jan 21, 2008 at 11:45 PM.
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Old Jan 22, 2008, 12:06 AM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
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the drawing looks good Carl ...but that mod in it self wont strenghen the fairing. still need glass or ply wood. but yes that method is great for securing the bushing s adding the extra bushings. keep going Carl
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Old Jan 22, 2008, 12:20 AM
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Formerly Denver. Now West Bend, WI
Joined Dec 2005
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Nice sketch Carl.

I'm amazed that you guys don't use sturdier servos. Seems like you're willing to spend big $$ on power, but don't invest appropriately in servo control.

Maybe it's just the heli guy coming out in me
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Old Jan 22, 2008, 12:29 AM
Registered User
Joined Sep 2004
764 Posts
One more thing...

Make sure the servo wires are glued SECURELY to the sides of the fuselage or you get this:

Phase 3 EF-16 Maiden and CRASH! (2 min 6 sec)
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Old Jan 22, 2008, 12:54 AM
Extreme CNC Alloy EDF
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Australia
Joined Mar 2006
11,756 Posts
I havent balanced my tailerons and I have noticed no flutter at 100+, but I used lite ply right at the very beginning on both F16's and boxed up the rear pylons, the brass bush is held firmly in the ply panels and epoxied in place. There is no play in the controls.

I understand the theory of balanced control surfaces, but dont get why being unbalanced would be the cause of flutter. When I visualise the controls I see the majority of weight hanging off behind the pivot point, which says to me more stability in the fin when travelling in that one direction.

I would have thought that slop and poor strength in the mounting points for the fins would be the real cause of flutter that people have experienced.
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Old Jan 22, 2008, 07:14 AM
Hangar queen hoarder
tailslide5_0's Avatar
Denver, CO
Joined Jul 2006
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Quote:
Originally Posted by LuckyDuc
I'm amazed that you guys don't use sturdier servos. Seems like you're willing to spend big $$ on power, but don't invest appropriately in servo control.
Not me. I'm using HS-65HB's in mine. I hope those aren't considered too 'cheap'.

I don't trust flimsy servo's in this thing, nor do I trust the stock taileron bushing setup that it came with. I've already yanked the paper and the bushing out, I'm doing it my old favorite way instead.
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Old Jan 22, 2008, 08:41 AM
Checking CG is for NERDS!
Smokescreen38's Avatar
Joined Jun 2005
5,347 Posts
So I inserted two pennies as far forward as I could into each taileron and they're still unbalanced (heavier aft of the pivot point). Obvioulsy, its better than it was before...but is that good enough? I hate adding weight like this!

What a great looking plane this is shaping up to be. I am going with the stock decal scheme and its really sharp (IMO). If this one goes well, I'll buy another to paint up with an authentic paint job... but I love the stripes.
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Old Jan 22, 2008, 09:15 AM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
21,272 Posts
smoke .02 cents should be way better than nothing.i believe balancing the stabs also takes some load off of the servo's ....and as far as big money on power......i did'nt spend any there either
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Old Jan 22, 2008, 12:15 PM
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USA, TN, Murfreesboro
Joined Sep 2006
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Hmmm, I wish I'd thought to glue down the servo wires with a couple of dabs of hot glue before I glued the fuse in place last night. I ran clear packing tape all along the side to hold them down, but glue would have been better, especially since low-temp hot glue can come off easily if things ever need to be replaced, too.

I also made some bushings to go in the fuse to hold the control rods in place, and guess what - I got so into building it that I forgot to put them in before I glued on the fuse, too! Argh! I already inserted flat carbon fiber rods into the top of the tail fairings, and I glued a 10mm long piece of 1/32 plywood to the bottom of each of them (along with taking out the stock bushings and regluing them), so I think the fairings should still be plenty strong enough since I'm just flying on stock power. Just stinks that I took the time to make the bushings and then forgot all about them. I ended up cutting off the tips of the brass sleeves that go in the fairings, and then gluing them inside the end-caps of a couple little yellow rubber-band holders for the ParkZone J-3 Cub. Fit pretty well! Just forgot to install them. lol.

I installed a cabon fiber rod through the body and into both of the wings as was suggested, too. Having that there makes me feel so much better about the wings ... they fit very nice and snug before gluing, so they ought to do great once they're epoxied down. I could just envision pulling out of a dive too hard and them snapping off otherwise, knowing my luck.
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Last edited by PerlAddict; Jan 22, 2008 at 01:42 PM.
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Old Jan 22, 2008, 02:04 PM
Checking CG is for NERDS!
Smokescreen38's Avatar
Joined Jun 2005
5,347 Posts
For such a well loved airplane, it seems that building one stock is asking for trouble!

Do you think they know about the shortcomings of the design??
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