weights and balance schedules and new add-ons

bencmaster · Post by **bencmaster** » Mon May 19, 2008 6:39 pm

If a Permit aircraft is on its MAUW with full fuel and two 189kg occupants, and a slightly heavier prop is added, what leeway does one have in massaging the figures back into place:

eg carry less fuel?
smaller passengers?

Ben

bencmaster · Post by **bencmaster** » Mon May 19, 2008 6:41 pm

Note to above:

C of G's within limits

steveneale · Post by **steveneale** » Mon May 19, 2008 8:02 pm

189kg each is two big bubas!!

Seriously, You don't say what engine but for Lycs you can you get a lighter starting motor for example. Replace one mag for EI?

bencmaster · Post by **bencmaster** » Mon May 19, 2008 8:55 pm

Big bubbas indeed. Sorry that should read Lbs.

steveneale · Post by **steveneale** » Mon May 19, 2008 9:16 pm

What battery do you have? We have an Odyssey PC680 that weighs just 15lbs and will spin our 0-320 with very little effort. It's AGM so doesn't lose its charge like a standard lead acid.

bencmaster · Post by **bencmaster** » Tue May 20, 2008 7:18 am

I have thought at length about these kind of things and there will be some I could do. What i was driving at was what the LAA allow in terms of passenger weight and possibly self imposed restrictions at MAUW in the fuel department.

J.C. · Post by **J.C.** » Tue May 20, 2008 7:31 am

The A.U.W. is the decider,how you achieve it is up to you.Lots of 4 seaters will not carry 4 pax and full tanks.
Simple answer is fly with less fuel to stay within limits,shed weight(aircraft equipment not needed,or diet!) .
Or difficult way, apply to the LAA for weight upgrade.
This would involve stress calculations and performance tests and maybe even upgrading of any highly stressed parts of the airframe.

Rod1 · Post by **Rod1** » Tue May 20, 2008 8:58 am

If the aircraft is a Microlight (ie under section S) then it will have a max empty weight which you must not exceed. If the aircraft is “group A” then you should have no problem unless engineering think it too heavy for the engine or the engine mounts.

Rod1

Mark A · Post by **Mark A** » Wed May 21, 2008 2:55 pm

It really depends on where you're starting from.

Possible weight saving that comes to mind include:
Lightweight starter or alternator (do you really need an electrical system?)
Replace one magneto with electronic system.
Interior trim - is it all necessary?.
EFIS instead of vacuum system or ditch gyros completely.
Extinguisher/1st aid kit - more than needed?

Carrying less fuel and going on a diet, of course, are both very simple solutions.