Optimizing CG with a Lycoming engine

[ykachuro]

Dan, thank you very much! This is exactly the info I needed!

This also incidentally reinforces my decision to go with a spring balanced elevators even though I already had the parts for the weight balance.

[danweseman]

Yuri
In short ,place everything as far fwd as you can. Many assume that with a 0-320 "class" engine you will need to put weight aft. This is not true. The Panther was designed for the 0-320 fixed pitch prop "class' of engines as the core engine. The Corvair and other smaller engines were a bit of a after thought in the design process. If you look over the sample CGs on our website you can see that the 0-320 aircraft have much more "useful" cg ranges if you want to use the aft baggage compartment. The only builders who would consider moving things aft is one who will fly only acro , and want to negate the use of the baggage area behind the seat. My own personal Panther is set up this way with a extremely aft cg because i do not do cross country in it anymore and i have optimized it to spin and snap roll.

Also if one were considering a "non approved" metal constant speed prop (very heavy and not recommended by SPA) they would want to look at this more closely. All others should mount everything possible as far forward as practical to create the most "all around usefull" aircraft.

Dan

[ykachuro]

I’d appreciate input on the following issue. I am approaching the stage where I need to start thinking about where to locate various electrical/avionics components, such as the battery, xponder, radio and alike. Although those don’t have much weight, but would still have some effect on the CG. The question I have is should I be trying to locate as much as sensibly possible aft or not.
My contemplated engine setup is Titan io340, light crankshaft, light cold induction sump, light flywheel, dual P mags, B&C SD8 alternator on the accessory case. This should be a fairly lightweight setup as far as lycoming engines go. 2 blade wooden prop. The airframe is long wings, spring balanced elevators, paint only on fiberglass parts, no lights, barebone interior. Minimal avionics (possibly a Garmin G5 and an MGL EMS (or GRT Sport 7” and their EIS), plus a Trig radio and a lightweight xponder and a some sort of ADSB setup, Probably a lithium battery. I am about 210-220 lbs.
thank know there is not much to play with in terms of optimizing the CG, but there are a couple of pounds and few feet to play with. Since we need to have the side skins in place for hanging the engine, I can’t really weigt the aircraft in configuration that would give me a more or less realistic W&B before I do the electrical system and avionics wiring — I’d like to have those completed before I rivet the skins on. In fact I’d much prefer to know if I’d be placing anything in the back/under the seat before my fuse bottom skin is rivetted on.

Please share your thoughts and experiences.

Thanks!