Weight and balance

LAMPSguy · #1 04-18-2012, 06:41 AM

I have searched and sent a few PM's but I was hoping to get a little more info.

I am researching 8 vs 7. Also, researching if my desired components will make sense from a CG standpoint. It seems that as the fuel is used CG shifts aft, enough to make the loading possibly an issue. This would seem to dictate planning the engine/prop weight, priming the inside of tail, etc so you can maintain that proper CG with the full 1800 Lbs.

The few W&B spreadsheets I have received seem to be C/S and heavier engines. I am looking to compare the useable envelope to that with maybe a Catto or other FP up front. When I ask about the various components, many people are telling me "it doesn't matter what is where, just put weight of people and baggage". Am I way off, or does it matter? Seems like it should. I am used to performing W&B for all weights/loadouts throughout the entire fuel usage range.

Long story short, I like the 8, but if realistically I can only pack 35 lbs of baggage (for aft CG limit on landing) and it all has to go in the front compartment, I will only get 5 lbs of that and my wife will get the rest! Would the 7 be better? Just want a few W&B spreadsheets to do the figuring myself!

LettersFromFlyoverCountry · #2 04-18-2012, 08:18 AM

Just did my weight and balance on the 7A the other day. right wheel: 431, Left wheel: 428. Nose 259.

FP prop, manual trim. .063 floors blah blah blah...came in around 1118.

I'm not a big guy -- 176 -- so i can only relay my calculations but the CG was only about an inch farther aft than the Van's sample.

Figuring a GW of 1800 pounds, full fuel and 90 pounds of baggage, the CG is 85.97 aft of datum (70 " forward of the leading edge)

The most aft CG (86.66) with minimum fuel (5 gals) allows 95# of baggage. Most forward is 80.36.

I don't see any significant problems with any of those, although the process did motivate me to go on a diet this week to lose 6 pounds and get down to the 'standard' 170.

I did all my calculations by hand so I don't have a spreadsheet to show you.