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Old Nov 17, 2014, 01:55 PM
copertop
United States, MI, Niles
Joined Jan 2003
35 Posts
Freewing F9F Panther CG

I just received my new Freewing F9F Panther. Assembled stock as manual recommends. On page 7 of the manual it states that the CG should be 1-3/4" (45mm) back from the leading edge. However, on page 8, there are stickers pasted over the original CG which indicate that the CG should be 1-3/8" (36mm). I have a 11.1v, 3600mAh battery installed all the way forward and it balances where the wing servo wires pass through the fuselage which measures 1-1/2 (38mm). I have included some pdf's showing the two pages I mentioned earlier. Any idea what the correct CG is, or should be? Any help would be most appreciated.
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Old Nov 17, 2014, 02:12 PM
chuck
santa barbara, CA
Joined May 2009
4,319 Posts
some say its fine at 1 3/4............ but for me closer to 1 3/8 was the ticket , especially on hand launch. i would start w/ the forward and go from there .

are u really going to fly it stock on a 3600? sounds heavy.
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Old Nov 17, 2014, 07:09 PM
copertop
United States, MI, Niles
Joined Jan 2003
35 Posts
I have this model set up as recommended by the manufacturer including battery. I have some static landing gear that I might install. I agree with you that I prefer my planes a little nose heavy with lower rates and expo set up. Strange that the manual has two different CG's, but I have read that a lot of these planes are tail heavy with the 1-3/4. Thanks for the help and suggestion.
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Old Nov 18, 2014, 01:40 AM
Registered User
prepps's Avatar
Sweden, Halland County, Varberg
Joined May 2013
189 Posts
I think that one cg is with landinggear and the other without,I fly mine without and I have the cg right on the wires for the ailerons.
I have a DrMadThrust 64 mm,60amp esc and i fly on nano-techs 1600 to 1800.
Get around 4min of flighttime.
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Old Nov 18, 2014, 12:18 PM
chuck
santa barbara, CA
Joined May 2009
4,319 Posts
gear should have nothing to do w/ cg.
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Old Nov 18, 2014, 01:44 PM
Registered User
Vienna, Austria
Joined Apr 2007
2,136 Posts
CG, flying in poor visibilty, and exhaust diameter

As Chuck knows, I am one of those who fly with more rearward CG, and I find it's fine.
A 1600mA 3s lipo 25c forward balances the stock plane fine (for me). Here's how easily it hand launches - hope you don't mind that I re-post that "lost in the fog" video, this is the season we Northerners face now (not you in Southern California of course)

F9F Panther EDF lost in the winter fog (2 min 6 sec)


Here's a new video, with the 7-blader and reduced exhaust diameter (nip tuck). Due to heavier motor and rotor weight went up a bit, and static thrust is down, so launch is more tricky, CG a bit more aft, too. It helped that I squeezed the exhaust into an oval shape so that the upthrust is not so pronounced. And I launch it rather downward than up. Speed is good though for a low-power setup on this plane, but lack of thrust clearly shows in the uplines.

F9F Panther 64mm Freewing 7-blade nip tuck exhaust (2 min 14 sec)


maybe one might say that the recommended CG will work if you have a fairly light plane, and a good thrust-to-weight ratio?

cheers
Clemens
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Last edited by mopetista; Nov 18, 2014 at 01:52 PM.
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Old Nov 18, 2014, 08:33 PM
chuck
santa barbara, CA
Joined May 2009
4,319 Posts
agreed, my issues were mostly on launch, loved to stand on it's tail

w/ the forward cg this was all but eliminated . but i think u may be correct lighter wing loading overall may allow a more rearward cg . the other thing mine did as lots of f9f's do is wag the tail.......just kinda hunted in yaw . this was also helped by forward cg but as soon as i put the wemo in it the extra thrust / speed helped this also . as some of us have found in other size f9f's they just dont seem to do as well heavy as some other airframes. love mine now w/ the wemo evo and a 1800/3. launches easy, cruises very nice at 1/2 throttle and gets around better than ever at wfo.

chuck
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Old Nov 18, 2014, 08:34 PM
copertop
United States, MI, Niles
Joined Jan 2003
35 Posts
Freewing F9F Panther CG

Thanks for all the help guys. I will try the plane with the current CG (1-1/2" back). The plane's AUW is 18.7 oz or 532 grams. Viewing the videos helped a lot. I did not see any plane hand launched that went straight up and then straight down as some have described it.
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Old Nov 18, 2014, 11:05 PM
chuck
santa barbara, CA
Joined May 2009
4,319 Posts
mine never went straight down but be ready for for it to try to go up . a little down was needed a few times until it got on the step.

chuck.
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Old Nov 19, 2014, 01:48 AM
Registered User
Vienna, Austria
Joined Apr 2007
2,136 Posts
standing on its tail at launch

Quote:
Originally Posted by copertop View Post
Thanks for all the help guys. I will try the plane with the current CG (1-1/2" back). The plane's AUW is 18.7 oz or 532 grams. Viewing the videos helped a lot. I did not see any plane hand launched that went straight up and then straight down as some have described it.
don't have a video of a "straight up - straight down" launch either, but you might easily have that when you're sloppy at launch.

here (at the start and at the end of the video) you can see what Chuck described, the plane standing on it's tail, and in the first case I got it on step, in the second I didn't, but I was lucky it was just coming down slowly.
With more thrust you may easily go "straight up and down", so my advice: concentrate on a straight and level launch, not easy given the awkward grip one has on the plane's rear end...

F9F Panther 64mm 7-blade stall crash tree & high alpha starts (2 min 20 sec)


when a F9F Panther gets into too steep an angle of attack (high alpha), the tailplane is no more effective because it's in the "slipstream" of the main wing (blanking)
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