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Old 08-14-2008, 05:08 AM
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CARS II
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Default Sig Lt 40 CG

Does any one knows the CG point for a Sig LT 40.

Thank you.
Old 08-14-2008, 05:26 AM
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UH60 Crewdog
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Default RE: Sig Lt 40 CG

Should be able to find it here... Sorry I just didnt have time to look through all the pages

http://www.rcuniverse.com/forum/m_34..._1/key_/tm.htm
Old 08-14-2008, 06:02 AM
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jetmech05
 
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Default RE: Sig Lt 40 CG

with an empty fuel tank the CG will be right at the main spar on the wing.....
are you planning on flying with an instructor at a local field?
Old 08-14-2008, 06:59 AM
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RCKen
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Default RE: Sig Lt 40 CG

The CG should be set 3-1/2" back from the leading edge of the wing.

Ken
Old 08-14-2008, 07:31 AM
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Default RE: Sig Lt 40 CG

Just finished mine. 3 1/2 to 4 1/4 is the stated range.

PEACE
Old 08-14-2008, 01:25 PM
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CARS II
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Default RE: Sig Lt 40 CG

HU 60
Jetmech
RCken
Harphunt

Thank you all for your replies. This is one of my club's trainers that was given to me to fix and get ready to fly, it has been some time since I work on one of this, at the moment the CG is at 4 and 1/4 but I'm missing the spinner so, once I get the spinner the CG should move foward a tad.

UH60, yes I also didn't have time to go throug all the pages, I did look on the Sig and Tower H. pages for the CG bu no luck there.
Jetmech, Thank you for your concerns, I happen to be one of the instructors at our club, thank you again. (this is the why I like to come to RCU to get help, you guys are always willing and able to give a helping hand [8D] ).

Here is a pic of my lates rebuild, 4 flights last Friday, that's my friend's Bob Boomerang. [8D]
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Old 08-15-2008, 08:35 AM
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MikeL@Sig
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Default RE: Sig Lt 40 CG

Just to be on the safe side here are the factory specs for you.

Set Up Specifications English Metric Directions
Elevator 9/16 inch 14 mm Up and Down
Rudder 1 inch 25 mm Right and Left
Ailerons Up 3/8 inch 10 mm
Ailerons Down 3/8 inch 10 mm
Center of Gravity 4 inch 102 mm From the leading edge
Dihedral 3 degrees 3 degrees Per Wing Panel
Incidence + 1-1/2 degree wing, 0 degree stabilizer
Engine Offset 6 degree down, 6 degree right
Old 08-15-2008, 08:56 AM
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Rcpilot
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Default RE: Sig Lt 40 CG

ANY trainer should always be balanced right on the main spar. That will give stable performance.

I still fly my old LT-40 for giggles now and then. It's highly modified, so can't be used as a trainer anymore. I have my CG set about 1/2" behind the main spar. It's quite............ nimble. (tail heavy as hell) I wouldn't recommend that for inexperienced pilots or on any plane you are using to train new students.

Mine has 2.25" cord barndoor ailerons and flaps. TH .75 engine. Taildragger gear. Elevator is about 1/2" longer cord than stock. I'm planning to add a rudder counterbalance soon. It still won't hold a knife edge very well, but I'm hoping a counterbalance on the rudder will add that little extra umph I need for a decent knife edge. I think some of the guys at the field probably laugh at me for flying a trainer even though I've been in the hobby 10yrs and mostly fly gasser giants now. Who cares? It's a blast to wring out a trainer and show those guys that I can do rolling circles and outside snaps with a trainer. I fly it low and fast.......... 40' off the deck at full throttle.........cut the throttle and toss all the sticks to the right and full down elevator. It's hilarious to see a Kadet doing outside snaps 40' off the deck. As soon as it rotates back to level flight I hammer the throttle again.

It's so funny to watch, I got to laughing with one of my buddies and almost fell down while flying.

It's ESPECIALLY fun to take that plane out on Thursday night (Student Training night) and show those guys what a "trainer" can really do. Soooooooooooooo many modelers rush to jump into that 2nd plane without ever flying their trainer to it's full potential. A shame really. Basic recovery and aerobatic skills can be learned on a trainer. They really WILL do all the aerobatic maneuvers, just not that pretty. But they will do it. Snaps, both inside and outside. Hammerheads. Harriers. Rolling circles. Flat Spins. Slow and dirty. Fast and furious. The LT-40 will do it all if you just give it a chance.

Having too much HP and larger control surfaces helps. But the stock LT-40 will do it all. Just slower.


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