Weight and Balance

Paul Jorgenson KE7HR

For weight and balance calculations for your BG, check out the calculators on my web page:


There are also spreadsheets out there (not mine) to help determine what should go where to keep the center of gravity in the proper range.

Paul Jorgenson KE7HR

On April 20, 2020 at 3:54 PM derry <dbelcher07@...> wrote:

It is important to watch weight, especially at the tail end furthest from the c of g.

As yours is built of the same ply as mine it will be more tail heavy than others built from Douglas Fir, Mahogany, or the Australian Gaboon, but will also depend on what instruments, radio, and transponder(?) is fitted, along with what battery you are going to use and where that is fitted.

I use two Sealed Lead Acid 12V-7aH Yuasa deep cycle batteries epoxied together end to end and wired in parallel and located on the keel member forward of the seat – It fits nicely between the console.  I will send you some pics.

This location was close to the avionics and helps bring the c of g forward.

My average total current drain in flight is just under 1 amp with radio, txpndr, and a supply to my cell phone that runs XC Soar.  The deep cycle batteries I am using are best for our purpose although in the past I have always just used the Yuasa standby batteries and they seemed to work ok and are less expensive 😊.  I recently set up a 12 watt trailer side-light as a 1 amp load and started doing proper capacity testing of the batteries after the previous one dropped a cell in flight a few years back.  I record the time to drop to 11.5 volts as my useful capacity for flight rather than using a lower figure that manufacturers charts use.  The thing to understand is that the deeper you cycle a battery, the shorter it’s life.




From: soloflight@...
Sent: Tuesday, 21 April 2020 9:44 AM
To: BGsailplanes@groups.io
Subject: Re: [BGsailplanes] Lockdown :(


I just dug out the original letter from caa approving the use of kauri ply for construction noting that birch plywood was required for spar shear webs. My main concern is reducing weight in the tail were possible to avoid 10x more weight in the nose. I'm sure it will climb well given the large wing area regardless 🙂





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