ScratchBuild

Hi there,

Do you balance the plane to C.G. with the petrol tank full or empty. Does this mean the charactersitics of the plane will change as the tank gets emptied while flying?

Any tips on balancing to C.G.?

vinnie

My Feedback: (1)

Balance the plane with an empty tank. Filling the tank will make the plane marginally noseheavy assuming the tank is forward of the CG. As the tank empties during flight the CG moves rearward slightly and the plane becomes more sensitive...but not much. Many Pattern and 3D planes have the tank mounted right on the CG thus rendering fuel quantity irrelevant.

MinnFlyer

My Feedback: (4)

Here are a few tips:

http://www.rcuniverse.com/reviews.ph...ew&reviewid=84

Spaceclam

Planes are balanced with the fuel tank heavy for several reasons, but only one i can remember offhand. When you take off, you have the power to compensate, whreas with a dead stick, you don't

ScratchBuild

Hi this makes a lot of sense I would rather like to get my plane back in one piece but on the other side the plane is going to be tail heavy at the end and for me as a trainee would most probably mean a crash!!

MinnFlyer

My Feedback: (4)

Why would anyone WANT to land a tailheavy airplane????

I repeat, a tank in the nose should be EMPTY when balancing.

ScratchBuild

Well,

I presume if you balance it with a full tank and the tank is empty at the end of your rounds it is going to be tail heavy, isn't it.

ScratchBuild

I was just replying on the quote above from spaceman, I truely read the article in your message and printed it to be used

Spaceclam

no no no. it is balanced correctly with the fuel tank empty so you don't have to land a tailheavy plane. that is why when you take off it is a bit noseheavy

ScratchBuild

Ok, spaceclam I then misunderstood your post. Thanks a lot.

Backwing

My Feedback: (3)

As far as balancing... The newest(June) issue of RCM has a good little article on building a balancer. I built one in about an hour, but then added a couple things to it.

Spaceclam

sory. in my post i accidentally wrote heavy instead of empty. i did not mean to be misleading

ScratchBuild

Thanks spaceclam, I gathered so much in the posts

I am going to get the RCM now for that balancer.

hookedonrc

I tried something in my Ultra Stick 60 that was recommended by a club member. I put the rear of the tank right at the CG, so that when the tank does empty during flight little change in balance is seen. The only question that I had during construction was if the tank would be to far from the engine to pump the fuel without help. I have flown the plane approx. 10 times now and I can say it works great. However, in probably other planes the fuse may not allow it. I just had the room

rogerswin

My Feedback: (2)

Now I'm going to throw in a little confusion,...

If your tank location is aft of the center of gravity point, - balance the plane with a FULL tank. In my Skymaster I'll have a separate tank for the aft engine which will be located behind the center of gravity.

Roger

rogwabbit

Ok,
I'd like to ask a simular question... I have a plane that I'd like to balance latterally.... The engine is off set (the line of thrust).. So the shaft is not actually the CENTER of the planes fuse' . Should I use the engine ANYWAYS as a referance or devise a way to balance the EXACT center line on the fuse?

Thanks in advance.

Spaceclam

no. not at least from my experiance. here's what i recomend.this will put a bit of stress on your plane, but screw in an eyehook in the ceiling. run a piece of strong string through it. tie one end to the front of the plane, just tie it around the fuselage because your engine is ofset. now tie the other end of it to itself, but with a big enough loop that you can put your rudder through.it is very sensitice, but if you are flying a trainer, it is not necessary. while you are at it, you may as well crosshair your cg and hang a plumbob from the eyehook. obviously, if the plane falls to the right, put some weight on to see how much is needed. if the plane is level, (nose to tail) the plumbob will point right to the cg. i have a happy face sticker right on that spot

murphy

My Feedback: (19)

Once again I'll digress to the my early "mentors" of R/C, who beat this saying into me as a lad:

"A nose heavy plane flys poorly,,,,,,,,,,,,but

A tail Heavy plane flys only once"

John
aka "Murphy"