I assisted two builders to do Weight & Balance on their newly completed
aircraft: a Zenith 750 Cruzer and a RV-9A.
The Zenith builder had previously built a Sonex. I asked how he did the W&B
for the Sonex. He said he just copied the data from the factory data sheets.
He was having trouble with the Zenith because he could not find any data in
his literature and the factory assist personnel would not provide that data.
After some discussion we found the one item in the builder instructions that
had not been checked off: "Perform a Weight and Balance measurement." That
page had a detailed work sheet with drawings to put all the measurement
numbers and calculations. He said "See. The page is blank and they would
not give me the numbers on the phone." After some "creative" work with my
scales, a ruler and a plumb bob, we had the W&B sheet filled in for all
loading conditions. He was somewhat skeptical about limiting the baggage to
less than the advertised 80 pounds when all other loads were onboard.
The RV-9A builder had the W&B procedures down cold. He just needed my
scales and a little help getting the airplane up the little ramps and onto
the scales. We tried differing locations for ballast weights on the tail to
compensate for the full IFR equipment in the cockpit and stay within the CG
envelopment.
Sid Wood
Tri-gear KR-2 N6242
California, MD, USA
---------------------------------------------------------
If you're buying a used homebuilt, be sure that the weight and balance
are accurate.
One problem is that planes tend to gain weight over time, but a more
serious problem is that some builders just copy other's builder's weight
and balance. Needless to say, that can be dangerous.
I mentioned that I knew of one builder that had done that (not a KR) on
a reply to a post that WW made, and he replied that when he did a mass
weight and balance on Pietenpols, that he found two of them that had the
W&B simply copied from another plane.
Sometimes, the person who did the W&B simply has made a mistake, such as
weighing a taildragger with the tailwheel on the ground, but sometimes
the person is just lazy or dishonest.
Dan Branstrom
----------------------------------------------
_______________________________________________
Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/.
Please see LIST RULES and KRnet info at http://www.krnet.org/info.html.
see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change
options.
To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
