Hello all,
Another question regarding balancing of plane. I have my plane (Extra 300) sitting on the CG machine (inverted) and on the CG marks. I was being very fussy and when the plane balanced out I placed a level across the underside of the fuse to see if it was sitting perfectly straight. I thought that was perfect, then I realized that the underside had a taper and not level like if I took the canopy off and used the level there. So as the plane now sits on the machine and looking at a side view, the leading edge is slightly facing down and and trailing edge of the wing is facing up. This to me seems like it would be a little tail heavy, because if I make the leading edge and the trailing edge level it would fall back on it's tail. So my question would be when balancing a plane do you look to see if the wing sits level or do you look at the fuse etc. I ask because I thought as long as the plane doesn't want to aggressively lean one way or another and kinds of balances/ sits in place it's good. Any advise would be appreciated.
Thanks,
Pat

From the side the nose of the aircraft should be slightly nose down or level - NEVER nose higher!

Thank you

What are you going to with your level, when you add fuel and it goes out of balance ? Confusing huh ..........

There should be a datum line on the plans, that's what should be level. If none is given, I'd keep the horizontal stab/elevator level if the stab is flat. If airfoiled, the leading &amp; trailing edge of the stab should be level. With most aircraft, the wing will then be at a positive incidence. Slightly nose-heavy is desired for the first few flights. <div>
</div><div>We were at the field when a member showed up with a new 1/4 Aeroworks Extra. He asked the club hotshoe to do the first flight. Mr. Hotshoe does a preflight, finds a couple linkages need adjusting, then turns on the transmitter and finds a low battery. The owner hadn't charged th enough, so we put it on a field charger. We asked about the CG, owner wasn't sure it was checked. I pulled up the manual on my phone, found the CG and we measured and marked it with tape and a marker. With a guy on each wingtip, we picked it up and found it was very close, just a bit tail heavy. Plane was level when lifted 1/4" behind the marks. Finished charging, took off and it flew near-perfect. </div><div>With 2 people, you can check it easily. </div>

The 'worse' case situation when flying is when you run out of fuel and by then the CG has shifted rearward....hopefully to the correct location. When you take off w/ a full load of fuel, yes you are slightly nose heavy but not that much. Remember a nose heavy plane may fly poorly, but a tail heavy plane usually flies only once!

Not if your good at repairs and balance it properly the second time around.

LOL!!!!!

This is the ARF forum? How many ARFs have plans showing the datum line?

Tom

How many plans period, show the datum line ?

Good point on the ARFs, but many of my plans have datum depiction, as well as build notes. Then again, they're older plans...,   <div>
</div><div>Forgot I was on the ARF forum. Will type slower.   </div>

"Forgot I was on the ARF forum. Will type slower. "

Now THAT's Funny!!!!

typing slower....


[&:][&:][&:]

DUH ! I don't get it.

You must be reading too fast

Is it really that critical? A few mm back and forth, better forth than back, shouldnt make much of a difference. For example my Phoenix Extra 330S 60-90 with the Dle20 is an inch (I think) nose heavy. Flies just fine for sports flying

Ameyam

Well it depends on the model size and type....for example a 36" wingspan an inch is a lot, whereas on my 50 cc Cap, not so much. Also the plane's design may have a lot to do with the CG...some models it is critical to put the CG right where they say it is supposed to be.

if its anywhere near level on the CG marks its safe to fly, if they supplied the correct CG location

Probably right, trying to cram a some extra years into the few that I have left. Trying to do everything faster.

I agree that it is not that critical. My Revolver 70 with a DLE-20 has just a little aft CG. But once I fuel it, I know that it will go to the forward CG. And once in the air with the fuel burning off, it should be just at a perfect CG for flight.

Only my personal thoughts.

Going back to the original question I always go by the fuse ..And I just go by eyeballing it...I stand back and when it looks level it usually is awufully close .. Very often the wing has positive incidence and very often the horizontal stabilizer has positive incidence too so going by the datum line is the best way to go ..I have just started using the Vanrssa Rig and am finding it fantastic...I was sceptical at first but I am converted now..If anything I go for a tiny bit nose heavy just to be on the safe side . When the plane is in the sling and looking level I will look to see where the plumb bob is pointing..I will adjust my weight accordingly ..