Tie Down Trouble

On Wed, 17 May 2006 20:25:30 -0400, Morgans wrote:

"A Lieberman" wrote
On my IFR checkride, I had to show my numbers for weight and balance.

470 pounds of meat in the front seats *required* 100 pounds in the baggage
department with full tanks. I elected to put in 75 pounds (yes, I brought
barbell weights) and account for fuel burn off to keep me in CG.

So, you had to take off out of CG, right? Fuel burn on the taxi and run-up
could not account for that much, right?

Is the landing CG range different from the take-off CG?

Just curious. :-)

Hmmm, never did a comp landing vs takeoff. Knowing the flight was going to
be 2 to 2 1/2 hours long, figured a forward CG of 25 pounds, that would be
lost rather quickly on taxi, runup and takeoff.

DE had no problem with my rational, so I don't think I was "unsafe" in
doing what I did. I weigh 190, and he was 280, and this is by far the most
meat I had in the front row, so I knew W&B would be critical.

With just me in the front seat and full tanks, I would need some ballast in
the back, that's how narrow the envelope is. While I have 30 pounds in the
back with oil, 25 pound barbell and the like, I felt like adding 100 pounds
seemed almost wacko, but the book said to do so.

My thoughts were that I would be burning off 120 pounds of fuel, so the CG
would shift gradually back. I didn't want to be far aft CG if my flight
went much longer, and as it turned out, it was 2 1/4 hours.

I guess my thoughts were that after the fuel burn off from the test, that I
would be aft CG had I stuck with 100 pounds, so I kinda compromised with
the "known" slight forward CG on take off rather then end up with an
unknown aft CG after 2 hour flight.

Bottom line is you are correct, in that flight, I should have figured both
the take off CG and landing CG to ensure that the W&B truly balanced.

That envelop for W&B in my Sundowner is a very narrow window.

Allen