Anyone out there up on C-340's? Interested in wt and bal. Looking at the books, seems like if you fill the seats up, you want to have some (alot) of wt in the nose compartment. Am I missing something? If so, is anyone using ballast on a regular basis to overcome this? Just curious about it. Long time Bonanza, Baron, King Air. Got those CG's down pretty well. This appears to be a new world. Thoughts? Thanks

Here is 6 people and 80 lbs of bags, and 140 gallons of fuel.
If you take out the baggage and add that back in fuel, you will be at the rear limit of CG.
( I assumed two 180 lb people in the front and four 125 lb people in the back.)

What app is that?

I owned a 340 for 7 years. A few points to keep in mind...

- They are all a little different, so you need to use the specific W&B for the specific aircraft of course. (Hopefully this is a given.)

- They tend to be a little tail heavy, but mine was not ridiculous. I regularly flew with me in the pilot's seat and my wife and 2 kids in the back, with baggage in both the nacelle baggage and rear shelf area. If you have a lot of stuff in the rear shelf area you need to watch the rear CG. But just put some in the nose. 4 adults in back with no one in the co-pilot seat is definitely a scenario you'd have to watch. But if you have 5+ adults on board, you probably have to watch the ZFW and gross weight as well - they are not tremendous load haulers (they do OK but not fabulous).

- When I was shopping for mine, I found a number with fairly egregious problems in calculating the W&B over time. So the CG, in particular, was often way off in the paperwork compared to what I'd expect of reality. But not only the CG, I saw planes weighed with full fuel and then subtract the weight of 203 gals of fuel - except they were configured with only 163 gal tankage. And so on.... Main point being that if you find one that seems dramatically out of whack, it probably is. It is worth spending a few hundred bucks to weigh it. Weigh it empty, make the effort to drain the fuel, you'll get a more accurate result.

What app is that?

Thanks Guys. I'll grab that app. Your reality matched what I was seeing when I was running scenarios. I won't be grossing out usually, but may have weight in the back. I am going to play with some ballast in the nose. Should work fine. Thanks again.

So what happens when folks move around in a light cc plane during various phases of a flight? Can you get into a fatal out-of-CG state?

On the 340, gross and ZFW are limiters. But once you fit inside those parameters, and assuming reasonable loading (bags in the nose first), the CG envelope is generally wide enough that you don't need to worry about people moving from one seat to another.

If my wife goes from the right seat to the third row, the trim needs to change, but I can't construct a reasonable scenario where she'll take us out of the envelope.

In any case, I think where aft or forward CG could become fatal is at low speeds. At cruise speed, you should have much more elevator control authority. As long as everyone is back to their assigned seats before the approach, I doubt you'd ever notice if you went out of CG.

Had a 340 a few years back and flew it for about 700 hours. Great airplane for the right mission. Built a W&B spreadsheet for it. (Attached below) Hope it helps!

Thanks!!

I have found that with our family of 5 (kids are 13, 12, 6) most configurations are well within the envelope, using 163 up to 203 gal fuel. Because we nearly always have bags that go in the nose.

Only once did I have a guy try to sit in the aft seat, and we had no baggage, that we were slightly aft CG (no factor if he was in the middle aft-facing row). He weighs about 260.

I’ll run some 4-adult scenarios:

2 guys, 2 gals (170#, 180#, 120#, 120#): allows 181# baggage, and 4.75 hours endurance (190 TAS in teens, 200 above FL200).

4 guys (170#, 3 guys at 180#): allows only 61# baggage with 4.75 hours endurance. 15# each is not a lot, but we've done it to go fishing in the Bahamas.

My 340 has the ability to carry 203 gal, so if it's just me and the wife, the airplane's endurance is more than our own (5.75 hours).

Or, weigh it full and subtract the well-known fuel weight.

my family swaps seats all the time. short of everyone cramming to the back luggage shelf, I doubt it would ever be a problem.

Do you have a GWI STC? Is there another version (340B) that risingup doesn't show?
http://www.risingup.com/planespecs/info ... e163.shtml

Or, weigh it full and subtract the well-known fuel weight.