Sig 300SX CG
#1
Member
Thread Starter
Join Date: Jul 2002
Location: Pioneer,
CA
Posts: 84
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.rcuniverse.com/forum/images/icons/icon1.gif)
I've done a search in this forum to find out where the CG is on a Sig 300SX. I see one thread that mentions 4 3/4 and 4 3/8, but it's not conclusive for me. Does anyone know where this CG should be?
I just acquired this plane and it has close to 1 1/2 POUNDS of nose weight. That seems incredible to me, especially since the plane seems to have been build according to spec. Before I go pulling the lead off I hope some folks here can share the benefit of their exerience.
Thanks.
I just acquired this plane and it has close to 1 1/2 POUNDS of nose weight. That seems incredible to me, especially since the plane seems to have been build according to spec. Before I go pulling the lead off I hope some folks here can share the benefit of their exerience.
Thanks.
![Confused](https://www.rcuniverse.com/forum/images/smilies/confused.gif)
#2
Senior Member
Join Date: Apr 2003
Location: Gainesville,
FL
Posts: 252
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.rcuniverse.com/forum/images/icons/icon1.gif)
I used to fly one of those planes with an OS 160 FX, a fairly light motor. I had to add 6 oz of lead on the firewall to balance where I wanted. Now, I can't remember what that balance point was, but I know I started with the book spec. It changed slightly as I flight trimmed it.
This ARF was designed and built to accomodate the Sig line of FPE engines, specifically the 2.4. I believe this is why most folks mounting a lighter glow engine end up tail heavy. You didn't mention what engine you are using.
Erich
This ARF was designed and built to accomodate the Sig line of FPE engines, specifically the 2.4. I believe this is why most folks mounting a lighter glow engine end up tail heavy. You didn't mention what engine you are using.
Erich
#3
Member
Thread Starter
Join Date: Jul 2002
Location: Pioneer,
CA
Posts: 84
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.rcuniverse.com/forum/images/icons/icon1.gif)
For the sake of anyone else 'searching' to find info on Sig 300 XS CG, here's what I discovered. The 'range' is between 4 3/8 and 4 3/4. After rebalancing the acquired Sig 300 XS and testing the CG, I had to remove ALL the lead in the nose (which was actually only 13 1/4 ounces) to get the CG at 4 5/8 -- mid range. I also had to move the battery back behind the fuel tank. I have no idea why this airplane had so much nose weight, but my calcs show the airplane balances ok with a Saito 150 up front, and only moderate amounts of added weight may be necessary for individual flying preferences.
#4
Junior Member
Join Date: Nov 2002
Location: Forrest City, AR
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.rcuniverse.com/forum/images/icons/icon1.gif)
My dad is flying the Sig Extra and after about 30 flights we're still trimming. So far the CG came out within range. He's using an old Quadra 35 that he converted to alcohol. It's a really light engine compared to mine that I'm still running on gas in a Laser 200. That Quadra pulls the Extra vertically out of sight. His total weight came out near 15 lbs. which we thought was kind of heavy, but with an ARF, you get what you get.
#5
Member
Thread Starter
Join Date: Jul 2002
Location: Pioneer,
CA
Posts: 84
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://www.rcuniverse.com/forum/images/icons/icon1.gif)
Had the first flight today. As I said, with the CG at 4 5/8, I'm still slightly heavy on the nose. Going to move the battery back to the rear of the servo cavity, but that still may not be enough since the flight this morning was without the cowling. With the cowling, the battery move to the rear may leave me right where I am now (longer moment from CG to nose).
First flight characteristics: Very stable and straight. Except at the top of a tight loop, it snaps out to the left side. Verified the elevators are throwing the same (no misalignment between them.) Interested in your and your DAd's opinion about this behavior.
Thanks!
First flight characteristics: Very stable and straight. Except at the top of a tight loop, it snaps out to the left side. Verified the elevators are throwing the same (no misalignment between them.) Interested in your and your DAd's opinion about this behavior.
Thanks!