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Old Jun 02, 2011, 02:45 PM
prop wash
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North of Toronto in Ontario
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Originally Posted by Ant View Post
Do you know why this has started to split? Have you had some fluttering, or is it just from normal wear tear?


.
My guess is a few to many mode one rough landings





Glen
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Old Jun 03, 2011, 04:01 AM
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Australia, VIC, Rosebud
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Originally Posted by biggy boy View Post
I still need to get my CG set up correctly, I'm having to dial in up elevator to keep it from coming down to fast. It is effecting my glide ratio for sure.
Still need to move the CG back some, maybe to 47-48mm!?!?!?

I'm guessing your Fox is a bit heavier from the glue!
I have extra weight from gluing my wing tips back on after several tip stalls on "mode one" crashes during launching.

Now that I have the new mode two spektrum transmitter may launches are successful.


Glen
Yeah, she does fly a bit on the fast side.
Are we checking that the tailplane is perfectly parallel to the wing base?

This is what I do. First pic is a cf rod lined up on the wing root base.
This rod extends to the tailplane. There you can see if the tailplane is parallel to the wing. Mine wasn't, it was deflected down relatrive to the wing base, so was forcing the nose down. So I loosened off both screws, lifted the back of the tailplane up a few mm and ran in a bit of hot melt.

Result? Much better but still needs a little more.

Kev
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Old Jun 03, 2011, 04:17 AM
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Are we test gliding?

I'm sure most of us are but for our newer members.......

Always do a series of test glides before launching a new or repaired/modded model.

This tells you a lot before you risk the skies. Give the glider a good strong straight ahead throw. A well balanced and trimmed glider should come out of your hand going level then gently start to nose down landing about 10 metres ahead after you have given it a little bit of nose up to flare out. That says she's all OK for trim & balance.

If she's not - then don't fly it. Re-trim/rebalance or do whatever you have to, and this might take as many as a dozen test glides to get it floating nicely.

THEN it's ready for the air!

This is much better & safer than finding out up there that she is flying too fast, too slow or not straight

Kev
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Old Jun 03, 2011, 07:01 AM
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Originally Posted by Berkie View Post
Yeah, she does fly a bit on the fast side.
Are we checking that the tailplane is perfectly parallel to the wing base?

This is what I do. First pic is a cf rod lined up on the wing root base.
This rod extends to the tailplane. There you can see if the tailplane is parallel to the wing. Mine wasn't, it was deflected down relatrive to the wing base, so was forcing the nose down. So I loosened off both screws, lifted the back of the tailplane up a few mm and ran in a bit of hot melt.

Result? Much better but still needs a little more.

Kev

Kev, I would be leary to measure incidence that way. It should be measured by location of leading and trailing edges of the wing. An easy way to do it is mark the points on the fuse with a pencil (with the wing in). Then a straightedge can be used to determine the tailplane incidence as you have shown (with the wing out).

Mine is fine stock. Shimming the stab for "Up" trim is ok as a last resort, but should not be used to compensate for a to far forward CG. It just creates a lot of drag and inefficiencies that are bad for a sailplane. Just my 2 cents....dont mean to step on anyones toes...
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Old Jun 03, 2011, 07:13 AM
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Originally Posted by rhawk1967 View Post
Kev, I would be leary to measure incidence that way. It should be measured by location of leading and trailing edges of the wing. An easy way to do it is mark the points on the fuse with a pencil (with the wing in). Then a straightedge can be used to determine the tailplane incidence as you have shown (with the wing out).

Mine is fine stock. Shimming the stab for "Up" trim is ok as a last resort, but should not be used to compensate for a to far forward CG. It just creates a lot of drag and inefficiencies that are bad for a sailplane. Just my 2 cents....dont mean to step on anyones toes...
Oops.....I should have been using the term "decalage" when referring to the angle of the Stab in relationship to the wing. I am awake now...need caffeine.
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Old Jun 03, 2011, 07:43 AM
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Because of the forward sweep of the Fox's wings the Cg will be farther back than one would normally think. I have flown at 55mm with no problem. The further back CG eliminates up trim and makes for a flat glide.
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Old Jun 03, 2011, 12:58 PM
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anybody have a programming guide for the stock 30A ESC? Mine does not brake....

Thanks,

Wim
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Old Jun 03, 2011, 03:04 PM
Ant
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Originally Posted by WimH View Post
anybody have a programming guide for the stock 30A ESC? Mine does not brake....

Thanks,

Wim
I would say "Try the first beep" but with my luck today it would set the ESC to self destruct.
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Old Jun 03, 2011, 03:39 PM
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Hey Guys, looking at my elevator, it suddenly dawned on me that it is counterbalanced. I am new to sailplanes, but looking at most other designs I have found hardly any that are like the Fox's.

Those end pieces are awful bendy out there on the tips....I can picture at speed the tips bending in the wind and giving more elevator than we are actually applying. Plus, drag is a big negative on a sailplane.

So,...what do you think....should I be the first and cut em' off? and see what happens?
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Old Jun 03, 2011, 05:31 PM
Ant
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rhawk1967

I'm not going to modify my Fox that much until HK comes out with replacement parts.

Speaking of which, anyone hear anything on HK starting to carry replacement parts for the Fox?
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Old Jun 03, 2011, 08:45 PM
prop wash
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North of Toronto in Ontario
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Quote:
Originally Posted by rhawk1967 View Post
Hey Guys, looking at my elevator, it suddenly dawned on me that it is counterbalanced. I am new to sailplanes, but looking at most other designs I have found hardly any that are like the Fox's.

Those end pieces are awful bendy out there on the tips....I can picture at speed the tips bending in the wind and giving more elevator than we are actually applying. Plus, drag is a big negative on a sailplane.

So,...what do you think....should I be the first and cut em' off? and see what happens?
I've been debating that too.

Glen
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Old Jun 03, 2011, 10:32 PM
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Originally Posted by rhawk1967 View Post
Kev, I would be leary to measure incidence that way. It should be measured by location of leading and trailing edges of the wing. An easy way to do it is mark the points on the fuse with a pencil (with the wing in). Then a straightedge can be used to determine the tailplane incidence as you have shown (with the wing out).

Mine is fine stock. Shimming the stab for "Up" trim is ok as a last resort, but should not be used to compensate for a to far forward CG. It just creates a lot of drag and inefficiencies that are bad for a sailplane. Just my 2 cents....dont mean to step on anyones toes...
Thanks rhawk. I have done as you suggest and that does confirm that there was no need to up-shim, so I'll take out the hot melt.
So, since I was flying with CG at factory figure of 40mm, it seems the factory is being conservative. It is starting to look like at least 50mm is the go. So I'll do that now & re-test

Kev
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Old Jun 03, 2011, 10:47 PM
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Thanks rhawk.

So, since I was flying with CG at factory figure of 40mm, it seems the factory is being conservative. It is starting to look like at least 50mm is the go. So I'll do that now & re-test

Kev
I did 50mm per rhawk and found it waaaaay better.
Before it just screamed around, now it glides and will still scream around if you want. I still don't have enough down thrust so for now I just fly the throttle to altitude and glide
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Old Jun 04, 2011, 02:35 AM
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Originally Posted by Ant View Post
I would say "Try the first beep" but with my luck today it would set the ESC to self destruct.
I somehow managed to get the brake on, but I'm not sure i did not change some other setting in the process, so I would really like to find out what esc it is... The range of beeps it produces is impressive, a bit, but not quite like the FM30A mystery esc....

Wim
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Old Jun 04, 2011, 02:48 AM
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Originally Posted by Helitime View Post
I did 50mm per rhawk and found it waaaaay better.
Before it just screamed around, now it glides and will still scream around if you want. I still don't have enough down thrust so for now I just fly the throttle to altitude and glide
Say Kerry, at 50mm that would mean a long way back to get CG for a 3S right?
Or did you add weight to the tail?

Kev
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