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Permalink Reply by Del Clowes on May 12, 2017 at 5:03pm

placed  mine in the tailcone  w/ small door, works great.

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Permalink Reply by Bob Pustell on May 12, 2017 at 7:05pm

I helped a friend with his 601XLB and we pretty much built the airplane (including installing the O-235 with prop and accessories) and then weighed it to figure the battery location. We suspected the battery would need to be aft so we waited until the plane was mostly built before locating the battery. We put any parts that were not yet installed into the spot in the plane where they would be (to make the weight distribution realistic) even to the point of using tape to hold a few bits in position. Then we weighed the plane and figured a CG without the battery. Once we knew where the empty CG was without the battery (too far forward, of course) we calculated where a chunk of "ballast" (the weight of the battery and battery mount) would need to go to get the CG right. We placed the battery and some weight to equal the mount in that spot and also layed a section of battery cable from there to the engine compartment) and weighed again. That second weighing gave us enough data to exactly locate the final location for the battery. It ended up just aft of the opening of the service access door into the belly of the plane. We built a mount that was attached to structure in the belly and the left side wall.

We knew that the XL tends to have overly sensitive pitch feel so we located the CG as far forward in the CG envelope as we could. An aft CG creates lighter pitch feel so we went as far forward as we could with the CG and ended up with reasonable pitch feel - light but not as light as some XL's that I have flown. Plus, leaving the CG legal but forward required a shorter battery cable than putting the battery further aft and the battery cable weighs a fair amount also.

The other thing we did is mount anything that could be mounted in the back of the plane as far aft as we could get it -- the ELT, a couple of remote electronic boxes, antenna, whatever. Those are all things you need to install anyhow and putting them as far aft as possible helped move the CG aft to compensate for that big lump of an engine. We also used a wood prop rather than a metal prop - wood props are much lighter so putting less weight on the nose also helps push the CG aft. For the same reason we went with a lightweight starter and alternator and did not put a vacuum pump on the engine. The lighter you can make the firewall forward the better off you are.

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Permalink Reply by Gil DeVault on July 16, 2017 at 5:41am

I will be using a wood prop, light weight starter and alternator. The starter and alternator are installed and my prop is being carved now by Ed Sterba. Guess I will wait until I can do a wt/bal before I install the Battery

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Permalink Reply by Charles L Smith on May 15, 2017 at 6:38am

Great advice.

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Permalink Reply by Chris M. Brammer, Jr. on May 19, 2017 at 3:45pm

Placed my battery, 23 lbs, as far back in the rear fuselage as I could reach from the bottom hatch. C.g. was at 11.5" empty and about 15.75 loaded. Takeoff was about 50 feet with 1800fpm indicated climb. This with a 74-2x58 prop. Top in was about 98mph.

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Permalink Reply by Richard Carson on May 22, 2017 at 7:04am

Thanks for all the advice I certainly appreciate it and I would like to speak with everyone that's gotta 235 in their aircraft to get more advice about some of the things I'll be running into with installing the cowling etc. My phone number is area code 937-266-3360 if you should have a spare moment please call me I have several questions I would like to ask.

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