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Old Nov 26, 2012, 08:04 AM
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bubbleman's Avatar
Joined Jan 2007
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Originally Posted by Rickflaguy View Post
You can use 65 but you can have problems with the CG to far forward. I would start at 70 and move either way.
I was test pilot on a FC that the builder had setup for the 80MM cg. It was a b**ch to get it back on the ground in one piece. When trimmed out for level flight at 60% power, a reduction in power would cause the tail to drop. The resultant increase in the angle of attack of the wing would result in rapid speed loss and a tip stall. With the cg at 70mm a reduction in power from 60% cruse will cause the plane to gradually loose altitude while keeping close to the same speed.

When trimmed this way it is possible to fly the FC with just the rudder and speed control channels. Amaze your friends by flying around with your right hand in your pocket.
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Old Nov 26, 2012, 09:01 AM
Will it ever Fly?
Flybynight2's Avatar
United States, SD, Platte
Joined Nov 2011
422 Posts
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Originally Posted by DIG2fly View Post
Must be over. Now $119
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Old Nov 26, 2012, 10:07 AM
ltc
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United States, MA, Mendon
Joined Mar 2010
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Originally Posted by bubbleman View Post
....
When trimmed this way it is possible to fly the FC with just the rudder and speed control channels. Amaze your friends by flying around with your right hand in your pocket.
I tried that with my single stick transmitter ... didn't work out exactly as you described
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Old Nov 26, 2012, 10:39 AM
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United States, IL, Joliet
Joined Jul 2011
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I've done left stick flying a few times. good to know should an aileron channel go bad....^^ not so easy on my Thunderbolt tho...
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Old Nov 26, 2012, 03:31 PM
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Joined Jun 2011
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Originally Posted by Boreel View Post
Thank you Ramblin,
great picture! I feel a whole lot more comfortable now. Funny though, the weight difference between our FC's. With a Turnigy 2650 20C mine would weigh about 1295 grams...while the only thing I added is the Turnigy light set (35 grams)....
I see you're still on a 2 blade prop? I think I'll use my 10x7x3 or 11x7x3 (wich I bought later anyaway since the 10x7x3 with the 2650 batt, only gave 274.2Wp with my amp meter). Also better clearance when ski's are mounted iso wheels or floats.
Another question if I may: do you also think that when changing back to wheels, the tail wheel doesn't fit too well?...I think it wiggles way too much. Do you have the same?
Thanks again
The inside diameter of the coupler for the water rudder or tail wheel is too large for the wire. I made up a thin shim the length of the coupler to take up the space and the set screws bear against the shim. It's not perfect but it does improve it significantly.
Flying with floats I don't have to worry about ground strikes so I'm using a 13x4 prop. It has lots of thrust and enough speed for me. I may switch to a smaller prop for flying from the lake after it freezes. However I noticed that the HK skis weigh 91 grams each so I made up a pair from foam that only weigh about 4 grams each and built them so the mounting height is the same as the floats. Have to wait a few weeks to try them.
.
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Old Nov 26, 2012, 03:33 PM
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Joined Jun 2011
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Speaking of flying in cold weather, I narrowly escaped from a bad situation yesterday. The lake is still open with a fringe of thin ice around the edges. It was sunny and calm so I decided this might be my last day to fly. I did a couple of landings and take offs and then discovered that I had lost rudder control. Then I started to lose more control, started to spiral down and made a quick, hard landing on the lake. I could see that the airplane was not sitting as high as it should so did not attempt to taxi back. I paddled out with my kayak and was relieved to find that the front of one float had pulled off the landing gear and there was no structural damage. However I found that the cause of my problem was ice on rudder shaft and on the aileron and flap hinges. The sunny day masked the fact that the air temperature was still below freezing and with each landing a little more water had splashed up and frozen on the airplane.
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Old Nov 26, 2012, 04:03 PM
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United States, MI, Royal Oak
Joined Nov 2005
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Ramblin, mine almost went down last weekend due to the same thing....my whole underside was covered in ice lol
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Old Nov 26, 2012, 04:10 PM
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United States, FL, West Melbourne
Joined May 2011
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I'll check the temp next time I take off here in Florida (heh heh).
I never would have considered that issue. Lucky you got her back.
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Old Nov 27, 2012, 11:18 AM
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The Netherlands, UT, Amersfoort
Joined Oct 2012
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Quote:
Originally Posted by Ramblin View Post
The inside diameter of the coupler for the water rudder or tail wheel is too large for the wire. I made up a thin shim the length of the coupler to take up the space and the set screws bear against the shim. It's not perfect but it does improve it significantly.
Flying with floats I don't have to worry about ground strikes so I'm using a 13x4 prop. It has lots of thrust and enough speed for me. I may switch to a smaller prop for flying from the lake after it freezes. However I noticed that the HK skis weigh 91 grams each so I made up a pair from foam that only weigh about 4 grams each and built them so the mounting height is the same as the floats. Have to wait a few weeks to try them.
.
Thanks Ramblin,
well clear and helpfull! I'll do the same regarding tail wheel. 13x4... so I assume a 1100 kV engine? I would think that with that set up the HK ski's would never be an issue. Mine 910kv with 11x5.5 already does about 0.89 to weight static when weight set at 1400grams! So even this set up shouldn't be an issue to fly it (no acrobatics though, that's why I'll go for the 10x73 or even 11x7x3)
Anyway, when the time's right (weather/water/ snow) I'll will post the outcome for sure.
Good luck and thanks again
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Old Nov 27, 2012, 12:21 PM
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United States, IL, Joliet
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I did a check in mine and found the nut securing the rudder horn mount was off. I wonder how long that's been missing?
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Old Nov 27, 2012, 05:44 PM
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Originally Posted by Boreel View Post
Thanks Ramblin,
well clear and helpfull! I'll do the same regarding tail wheel. 13x4... so I assume a 1100 kV engine? I would think that with that set up the HK ski's would never be an issue. Mine 910kv with 11x5.5 already does about 0.89 to weight static when weight set at 1400grams! So even this set up shouldn't be an issue to fly it (no acrobatics though, that's why I'll go for the 10x73 or even 11x7x3)
Anyway, when the time's right (weather/water/ snow) I'll will post the outcome for sure.
Good luck and thanks again
Boreel,
I am using the 910kv with the 13x4 prop. Although I mostly fly scale and try to improve my landings, I also enjoy a few aerobatics - loops, rolls, Cuban 8's, inverted flying and spins from high altitude. Watching the plane spiral toward the water usually gets a gasp from a new audience.
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Old Nov 27, 2012, 08:50 PM
JOHN 3:16
Sammy70's Avatar
Central Ohio
Joined Feb 2008
6,259 Posts
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Originally Posted by Rickflaguy View Post
You can use 65 but you can have problems with the CG to far forward. I would start at 70 and move either way.

We have 3 FunCubs in service and have flown them all with CGs anywhere from 55-75mm with no problems at all...
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Old Nov 27, 2012, 09:45 PM
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Japan, Miyagi Prefecture
Joined Aug 2012
154 Posts
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Originally Posted by Sammy70 View Post
We have 3 FunCubs in service and have flown them all with CGs anywhere from 55-75mm with no problems at all...
Excellent! That jibes nicely with the theoretical optimum CG range we calculated on the previous page (56.25 ~ 74.25mm).

Right, I'm convinced.
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Old Nov 27, 2012, 10:32 PM
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United States, FL, West Melbourne
Joined May 2011
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Originally Posted by Sammy70 View Post
We have 3 FunCubs in service and have flown them all with CGs anywhere from 55-75mm with no problems at all...
OK I'll go a bit forward and see.
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Old Nov 27, 2012, 11:17 PM
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Australia, VIC, Coburg
Joined Oct 2007
619 Posts
Damn it.. bent another prop... i think the landing gear is getting weaker lol Time to do the landing gear mod!
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