Van's Air Force
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RV-4 sample weight and balance
- Thread starter Xkuzme1
- Start date
n82rb
Well Known Member
I could post mine but it won't do much good unless it matches the equipment in the plane you are looking at.a o-320 fixed pitch wood prop is totally different than a o-360 c/s model. A fixed pitch will go out aft with a heavy person and a 360 c/s will be nose heavy solo. Also, empty weight is all over the charts depending on equipment .
Bob burns n82rb
Bob burns n82rb
Mark Albery
Well Known Member
Here's mine
I've changed mass units to kg for my preference, but it would be easy to switch if you prefer Roman units (as still used in Liberia, Myanmar and USA I believe
)
I did have a copy of the RV mass and balance database that Dan Checkoway compiled, but can't find it at present.
Be wary of the different datum used depending on the age of the plans. I believe it was changed from 50" to 60" when the cowls changed and prop extensions put the forward-most station below zero.
I've changed mass units to kg for my preference, but it would be easy to switch if you prefer Roman units (as still used in Liberia, Myanmar and USA I believe
)I did have a copy of the RV mass and balance database that Dan Checkoway compiled, but can't find it at present.
Be wary of the different datum used depending on the age of the plans. I believe it was changed from 50" to 60" when the cowls changed and prop extensions put the forward-most station below zero.
USE THIS AT YOUR OWN RISK
The link below will bring you to google drive, then from there you need to click the download arrow to get the excel file.
To make it simple, only change the data in blue. the arm value in yellow is calculated from the scale weights, but you can simply type in a new arm value. NOTE: the arms in this are based on a datum of 50 inches. Most RV4s seem to have used 60 inches, but the plane I made this for used 50. This is a fairly all inclusive spreadsheet that you can start with the scale measurements, enter oil quarts, change the remaining fuel after flight, change the cg chart envelope, etc.
https://drive.google.com/file/d/0Bx3YpAZ5ckLIaTNuVmk2dTFRY0hEdU91V21aUzlPdXhwLXdr/view?usp=sharing
I'm showing 68.7 - 77.4 for the acceptable CG limits according to the build manual for the RV-4. Looks like your numbers are about 10 inches off. I remember being in a similar situation years ago before reading the builder manual. What gives? Can anyone chime in to confirm the RV-4 CG limits fwd and aft?
Thanks.
keijidosha
Member
Plans call for the 60" Datum and the 68.7 - 77.4" CG. The 50" Datum would produce a 58.7 to 67.4" CG. Confusing compared to original plan examples.
That's it, perfect! Very confusing, thanks for the help. The new Dynon w&b module is awesome.
