Author Topic: c.g. of camrian fun fighter 109  (Read 7810 times)

luke

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c.g. of camrian fun fighter 109
« on: August 03, 2008, 22:01:54 PM »
i have two me 109 cambrian fun fighters , the first one flies beutifully,
but......i came across a half built one and decided to take it on , i finished it in the desert camo detail..... on the different plans the two cg`s were different  the first 109`s c.g on the plan was 55mm from the leading edge......but the second one was 75mm from the leading edge ,i have put strips of lead as far forward as possible but it still climbs like a homesick angel, but whats worse the stall speed is an awfull lot higher in the second one??? i actually did a kind of a snap roll one day doing a tight fighter type turn but luckilly enough i was high enough to get out of it
ANY IDEAS FOLKS ?????  :!:
dodgy tip stalling plane

[/img]
nice flier

Fred

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c.g. of camrian fun fighter 109
« Reply #1 on: August 05, 2008, 09:33:27 AM »
Hi Luke,

To me, it looks like an Incidence issue  :?:
Have you checked that ?
The CG mostly depend of the incidence.

Have you tried to check the CG in flight too ? (45 degrees descent, release the sticks and see what happen..). What are the results ?

Hope this help.

Fred
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luke

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c.g. of camrian fun fighter 109
« Reply #2 on: August 05, 2008, 22:36:25 PM »
hi fred , thanks for the info, when you say incidence is that the tail plane incidence?? i think there might be an awful lot of rippin to do to remedy that, ill have to see if its worth doing, but when i picked up the half built kit the tail was broken off at the  the slot for the stab,i had to cut a brand new tail from hard balsa and propably got the angle wrong,would some down thrust be a better option????
luke

Fred

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c.g. of camrian fun fighter 109
« Reply #3 on: August 06, 2008, 07:38:20 AM »
Hi Luke,

Yeah, tail, or even wing incidence  :?:

Compare the angle between the tail and the wing to see...
But next flight, do a CG test and see the results  :?: Sometimes is easier to move the wing incidence a little when it's too late to do it at the stabilizer.

Down thrust can also be an option, but that will work only at a certain speed and will not fix your triming problem.
More "complicated", if your radio do it, is to mix the elevator with the throttle... Not sure that worth the effort though
Education is important, but flying RC planes and gliders is importanter!

luke

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c.g. of camrian fun fighter 109
« Reply #4 on: August 07, 2008, 18:44:01 PM »
thanks fred i might try that