Creating a Weight and Balance Envelope

[rockitdoc]

I rooted around a bit here and on the net and came up pretty empty. Anybody have a good source for setting up a weight and balance envelope? I've weighed my bird empty and have the arms and weights of the gear and location of the firewall. All arms measured 72" from the leading edge of the wing.

 

[RV7A Flyer]

Isn't this defined by the engineers, and given in the Van's documentation for your model?

 

[rockitdoc]

Isn't this defined by the engineers, and given in the Van's documentation for your model?

I'll look, but won't it vary depending on empty weight?

 

[BobTurner]

I'll look, but won't it vary depending on empty weight?

What he meant was, the method of measuring, and the various moment arm lengths, and the allowed limits, are all in the documentation.
Many people enter the measurements, and then that day’s conditions (pilot weight, passenger weight, bag weight, fuel on board, etc., into a spreadsheet, which then does the required calculations to show total weight plus cg location. My personal Excel based spreadsheet even calculates cg at zero fuel (landing), as the cg moves on most RVs as you burn gas.

 

[Kyle Boatright]

There are sample weight and balance forms for download towards the bottom of this page. You should be able to download one, update the empty weight and CG numbers to match your airplane, and go forward from there. If you need help creating a spreadsheet from the .pdf, you're free to reach out to me...

Downloads - Van's Aircraft Total Performance RV Kit Planes

Van’s provides a variety of downloadable items in support of kits and flying aircraft. Choose from the type of downloads you need below. RV-12/12iS avionics software downloads Dynon Skyview Garmin G3X Dynon D180 RV-12 and RV-12iS Electrical System Diagrams RV-12 misc. documents Canopy Warning...

www.vansaircraft.com

 

[RV7A Flyer]

For the OP, the envelope data is here https://www.vansaircraft.com/wp-content/uploads/2019/01/RV14Awb.pdf .

 

[rockyfatcat]

Design C.G. Range.............................18%-29% of wing chord OR 82.08 - 88.24 inches aft of datum.

As the aircraft manufacturer, did you change the positioning of any of the big flat bits? Wings and tail-feathers? If not you would be well advised to stay within the design CG range.


When an aircraft's center of gravity (CG) is at or beyond the extreme limits, it can drastically alter flight characteristics, making the aircraft difficult or impossible to control. Forward CGs can lead to increased stability but may hinder maneuverability and control authority for takeoff or landing.Conversely, aft CGs can cause instability, potentially leading to violent stalls or uncontrollable spins

 

[RV7A Flyer]

Design C.G. Range.............................18%-29% of wing chord OR 82.08 - 88.24 inches aft of datum.

...for Normal category (I believe...might be Utility category). Aft limit is 86" for *aerobatic* category (and a lower MGW). That's for the 14A, per the documentl.