adjust the CG or trim
 

I have a Fliton extra 330s freestyle and I can get it to balance a little nose heavy on a CG machine but I have to be right dead on the angle where the plane will balance or else the tail or nose will drop in a second. When I'm flying the plane and let go of the controls the plane will dive fast!, so should I trim this out or move my battery back and forget what the CG machine is telling me and adjust the CG to what the plane is telling me?. I'm balancing the plane with the fuel tank empty , plane upside down and the fuel tank is maybe 3-4 inches behind my saito.

Thanks

Greg

RE: adjust the CG or trim
 

Trim first. One way to check your CG in flight is to trim for level flight, then put it in a dive, at maybe 30 degrees, then let go of the controls. If it climbs sharply, it's nose heavy; if it dives much more steeply, it's tail-heavy. If nothing exciting happens, you're OK.

RE: adjust the CG or trim
 

Yes, Check the CG on the ground, then trim in the air. ALLairplanes need to be trimmed in air, even if the CG was perfect. Do both, and check the "hands off flying" and make sure it goes straight, then do what top gunn said, put it into a dive, and climb, to make sure it stays climbing, and stays diving.

RE: adjust the CG or trim
 

After I flight trim I do the dive test but drop it straight down, not at any set degrees or angles, just straight down. I watch the plane to see if it tucks in any direction then I land it and look at the controls with the plane and radio still turned on. If I have up trim in the elevator then I know it is nose heavy and if I have down trim in the elevator I know I am tail heavy. Most people are happy with the plane slightly nose heavy but the only way you will know what you like is by moving the CG around a LITTLE bit. I like my Extras CGed neutral but I have others I like a bit tail or nose heavy. One of those pilots choice thing.

RE: adjust the CG or trim
 

I've always been taught to trim for level flight......put the airplane into a 45 deg climb...roll inverted...now let go of the sticks......if the airplane's nose falls you're nose heavy...if the airplane climbs your tail heavy.....

RE: adjust the CG or trim
 

Yeah, I don't mean to repeat what has already said, but no matter what you do, do not set the CG for tail heavy. You should START out with at least a nose heavy plane that is easy to land no matter what you do with it after that. So, set it up as mentioned, then fly it. Trim it for hands off straight and level flight. That way you can land it when you are ready to land it.

There is a saying that I've seen here on RCU. Nose heavy planes fly ok, tail heavy planes fly once.

All the adjustments should be tweaked in after your initial CG setting so that you get what you want, but the first flight should always be with a nose heavy plane. Now, after saying that, I don't mean that as soon as you lift the plane at the CG point, it immediately drops the nose to the point where it falls to the ground and bury's the nose about 5 inches deep.. no, it should be set so that it will slightly drop the nose with your fingers or the CG tool set at the CG point.

CGr.

RE: adjust the CG or trim
 

Greg,

Check this thread out, which explains a similar problem:
http://www.rcuniverse.com/forum/m_95...tm.htm#9527315

RE: adjust the CG or trim
 

Just what jtmech said, if the airplane goes into a 45 degree angle up, roll, and it goes one way up or down, and its trimmed out level flight, you are nose/tail heavy.

RE: adjust the CG or trim
 

Greg,

Check this method of trimming:
http://www.hebertcompetitiondesigns....ngulation.aspx

http://74.125.47.132/search?q=cache:...&ct=clnk&gl=us

RE: adjust the CG or trim
 

This being a beginner site I think it is important to add that checking th cg this way only works on symmetrical airfoils. If you try this with a semi or flat bottom you will be chasing the cg issue until you finally make it to unstable to fly. Most trainer and sport planes (not stunt or 3D) work best at the factory settings.

RE: adjust the CG or trim
 

Define factory settings.

Do you mean set it where the book says to set it?

This is good advice because a beginner would have no real idea what to do with the CG. Saying nose heavy means what? As I said, if the thing falls off of the balance point and digs the nose about three inches into the ground, it's to nose heavy.

But, one would hope that beginners follow what we've been trying to drill into them for years now.. do this with the help of an instructor or someone with a good solid RC background so that it's done right the first time. Doing it alone, as a beginner, is simply the blind leading the blind.

CGr.

RE: adjust the CG or trim
 

Are you balancing the plane upside down or right side up? Which ever you are doing it sounds like you need to flip the plane over and balance that way. By fliping I think you will find the plane more stable on the CG machine.

Bruce

RE: adjust the CG or trim
 

Well, not exactly. If he IS already balancing it inverted, then he's ok. If he is not, then you are probably correct.

CGr.

RE: adjust the CG or trim
 

There is this third situation that may happen to models with thick airfoils:

RE: adjust the CG or trim
 

Thanks everyone for your replies.

Landeck, I’m balancing the plane upside down with the CG machine and I can get it to balance slightly nose heavy, but if the nose is one degree lower or if the tail is one degree lower ether end will drop like I’m 20 degrees from the point where I can balance the plane. I was making a huge mistake by assuming that a balance plane on the ground is almost a balance plane in the sky – lesson learned after reading everyone’s helpful replies. I also was wondering if this was due to having a full tank of fuel, but even when I was low on fuel the plane will still have the same flight characteristics. My first plane was a NexStar and second was a Pulse 60, both the ARFs were easy planes to balance and flew like they were balanced planes with very little trim needed when they were in the air. But this Fliton extra 330 is my first mid/symmetrical wing and my first plane that is a hybrid kit / ARF. After ready everyone replies I’m going to have one of the experience guys at my field perform some dives and have the plane tell us wear to adjust the CG.

Thanks again everyone,

-Greg

RE: adjust the CG or trim
 

If you trim for straight and level flight hands off then you can just land and see where the elevator is sitting to get an idea of how your CG is set. I use the dive test on my pattern planes but the reason for the tucking is how the trim is on the elevator so it tells you the same thing. There are several ways to come up with the same answer. I still use my old trim chart I have had for years, I see new ones come up all the time and try using the new improved ways but they all seem to work out in the end. Like CG mentioned, just watch out for tail heavy, it's a real thrill!! I was always taught to trim at full throttle but I started to trim at half throttle and my planes fly a lot better FOR ME these days. In time you will find the method you like best for yourself.;)

RE: adjust the CG or trim
 

My apologies I meant factory, or design, specifications. AKA CG range

RE: adjust the CG or trim
 

Hi just got a fliton 330s freestyle from a friend can anyone give me the cg range for this plane thank"s Charles.

RE: adjust the CG or trim
 

http://www.rcuniverse.com/forum/m_2524947/tm.htm

Over 80 pages of info on this plane, I think every one is starting at 127mm but go thru the forums to verify. The manual that comes with the plane says 88mm which is wrong but they may have updated the manual since then.