Weight and Balance exercise

[Robert Lees]

Re: Weight and Balance exercise

Oops...syntax error...I have corrected it, but will post to you, Wayne.

Rob

[mhorowit]

Re: Weight and Balance exercise

If this is related to an insurance claim, then I suggest you delete the thread.

Nothing to do with a claim; just an upcoming discussion with the FSDO - MIke

[VictorBravo]

Re: Weight and Balance exercise

One more thing... make sure that when you weigh the airplane it is in the level flight position. If it is three-pointed, your empty weight CG would likely be off.

The reason for that passage in the book is because I believe the seat is on the CG.

Bill

[mhorowit]

Re: Weight and Balance exercise

One more thing... make sure that when you weigh the airplane it is in the level flight position. If it is three-pointed, your empty weight CG would likely be off.

The reason for that passage in the book is because I believe the seat is on the CG.

Bill

Thanks VB; don't know if the a/c has ever been actually put on scales - Mike

[mhorowit]

Re: Weight and Balance exercise

Mike, divide the moment by the weight. 24311/1250=19.4 And use big people if you want to, it's your world

Yep, that was my problem; not dividing total moment by total weight; thanks, MIke

[Hank Jarrett]

Re: Weight and Balance exercise

Mike,
I thought we had a discussion on weighing your plane when you were down here. When I got my plane it was very sensitive on the controls (mostly in pitch) but not so bad as to be hard to fly, actually nice and spirited. I thought it was just because it was pre-war and a very light ship.
Being an engineer who can't EVER leave anything alone I weighed my plane to see where the CG really was (got suspicious when I saw the W&B was from the 40s). What I found was the W&B was WAAAAAAY WRONG! I was flying her a little aft of the max aft CG! If I had put anything in the baggage sling and gotten slow and nose high I could have ended up in an unrecoverable spin.
I ended up ripping about 30# of excess wiring out of the tail and removing an unused VOR ant from the tail. The wire didn't GO to anything. It was like every time anyone wanted something in the tail they ran another wire and never took anything out.
With the junk out of the tail (as well as a bunch of trash added to the back of the panel and in the wings) I found I really DID have a light bird ands she flies MUCH better (not as sensitive but still light and loads of fun).
The interesting thing is, not one entry was in the logs for any of the junk I took out. I literally FILLED a paper box with things people had added over the years with no log entries and no weight and balance confirmation. I plan to re-weigh my plane on reassembly after the repaint and make sure everything is within limits. If you don't weight her yourself, you really DON'T KNOW where the CG is!
If your passenger lies about their weight you don't know either. Ever take a woman you don't know for a ride at a fly in? Think she told you her real weight?
Hank

[mhorowit]

Re: Weight and Balance exercise

Hello Hank - as a matter of fact, my A&P did suggest we weigh the beast, but we never got around to it. But I think I'll do it on the new plane.

I'd be tempted to start by borrowing three bathroom scales; alternatively, lifting the beast at the engine with an in-line scale. Is there a better way? How would I figure the real CG? - Mike

[lktiller]

Re: Weight and Balance exercise

Mechanical bathroom scales only go to 300 lbs. One main weighs more.
use two scales with a board across them. set the wheel on the board. Add the two scales & subtract the weight of the board.
Add the three wheel measurements for total afct weight.
problem with mechanical bathroom scales is repeatability. Use the electronic ones. Calibrate against a standard weight for accuracy.

A metal prop should be figured into the w&b calculations. McCauley 1a90 +21lbs @ -46 moment for a bc12d

Check the type certificate for moments..

[Robert Lees]

Re: Weight and Balance exercise

I have an friend who has to flly holding the stick forward with full down trim

Ron, get your friend to check the trim tab angles (25 deg up, 30 deg down). It is possible the trim cable has slipped.

Rob