Where Is Correct Balance Point
Can't believe that after all these years I'm asking this question. Possibly it's because I've always balanced my airplanes the old "put finger here" way and things sort of worked out. Now that I have a fancy tool to balance my airplanes I'm a bit confused.
If the plans/manual gives the balance location as 3 3/4" to 4 3/4", do you just pick the middle of the two locations? Only the GP Big Stik 40 that I have actually gives a "start here" location (3 3/4") and then a range of 3 1/4" to 4".
Would appreciate some advice before I start adding weight to my airplanes.
From what the plans on my at-6 said, and other planes, the more forward the CG, the easier it will be to fly. The most rear CG, it will perform quicker manuevers such as rolls ect. On my At-6, I have the CG in the more forward area, and it flew fantastic.
Good Luck.
Gray Beard has it right. I thought it was backwards myself for a minute until I visualized what he was saying. LS88 is also right in that a more forward CG will generally provide more stability where a rearward CG provides more responsive flight. In the past where no starting point was given I would generally start 1/3 back from the forward limit shown on the plans and adjust from there. This is just a personal habit, and not something recommended to be done. If possible I would seek info from someone who owns and flies the particular aircraft you're building to see what their experience is.
The plan or with an ARF the C.O.G given in the manual is just a starting point. Unless you built exactly as the designer did and installed identical components in the same locations your results will vary. Start with the suggested balance point and then fly it to determine if it's balanced well. If you trim it for hands-off level flight and then pull up to 45º at crusing speed and half-roll inverted then release the sticks does it hold the line? If the nose falls it's nose heavy. If it climbs steeper on it's own it's tail heavy. Knife-edge will tell you about tail-heavy also. When in doubt, start out nose heavy.
A very nose heavy airplane flies poorly. A very tail heavy airplane flies once.
Hi all. I was hoping to get some CG advice regarding a new Pulse 60. The plane is super nose heavy. It's so nose heavy it can't even be held at or near the CG point using fingers. I built it as per instructions, stock, but using a 75AX engine. Moving the battery back doesn't help. I'd really prefer not to add a lot of weight to the tail if possible. Any suggestions as to what could be wrong or what I could do to fix it? Many thanks!
Bruce
Graybeard,
Would you please read - Lipo's for a flight battery.
and tell me what you think.
Teddy
Sorry but it is really out of my realm. I had to go to the WF forum myself just to figure out how little I really know, they set me straight. Also, if you have a question for someone you may want to hit them with a PM, I don't subscribe to any threads, you get a hit on your email every time someone posts something. Really can clog up your mail!!
Hey Greybeard,
It kinda scary when you start being considered a Guru, isn't it?
If you balance toward the rear location, expect the airplane to be quick to respond to the recommended elevator deflection. Matter of fact, expect to re-rig the elevator connection to get less deflection, as you probably won't need or want the over sensitive pitch response that comes with a more efficient elevator.