Weight & Balance Imminent

[Skippydiesel]

Hi All,

With luck I will be doing my W&B next weekend .

I have some pre show nerves because my Sonex Legacy (A) is just a "tad" out of the ordinary:

[list=]Rotax 912 ULS mounted on Sonex Mk 2 adapter
Airmaster CS propeller
Leading edge wing tanks 30L x 2
Fuselage header tank, in approximate position of standard Sonex - 35L on ground 40l in air[/list]

I would like any constructive advise that may be forthcoming

[sonex1566]

I wouldn't worry too much, I went from an AeroVee to Jab3300. My empty weight went from 301kg to 308kg on an 'A' model, all of the weight gain was firewall forward. My empty CofG works out at 22% MAC, which works better than the VW with me sitting in it ( I'm built like a brick outdoor dunny ). I'm certainly interested in how yours works out....lighter engine, but more weight in fuel tanks but closer to the CofG. Now as I like to put my money where my mouth is I reckon that your aircraft will be at most 3/4" rearward CofG than mine and similar weight provided you haven't put too many shiny toys in the dash. Good luck!

[Skippydiesel]

Hi Richard,

Thanks for the reassuring words.

I am located about an hour west of Sydney, where might you reside?

[sonex1566]

I fly out of Gawler, about an hour North of Adelaide. If it wasn't for low clouds, mountains and a flood it would be good to catch up. Just maybe the rain will stop before Christmas!

[Murray Parr]

I'm interested in your results as I am almost ready to do a W&B on WXB0015 with the Rotax up front. I am hoping but not real confident that the balance won't be too far aft. I tried to put everything forward of the spar and managed to only have 3 additional items aft of the spar, the ELT is under the seat and its antenna is on top of the turtle deck not far behind the canopy and the VHF antenna is underneath and between the rear wing spar and the seat. I have a lighter weight tail wheel (from Peter Anson) which weighs around 400 grams lighter than the light weight Sonex one so that should help too. The only other thing behind the CG is the baggage compartment which weighed 1800 grams so I will take that back out if it's an issue.

I put a spring scale on the tail wheel in the level attitude and it weighed just shy of 41lbs. I read some time ago that 36lbs was more common. Anybody else have any data on this? I am hoping the spring scale method isn't accurate as I would be surprised if it came out tail heavy given that I put most things as far forward as possible.

[Bryan Cotton]

There is a post with a link to W&B info. This came up recently.

On this page:
viewtopic.php?f=21&t=1760&start=50

My W&B shows 40.5 on the tailwheel when empty.

[Murray Parr]

My W&B shows 40.5 on the tailwheel when empty.

That's a relief, maybe I am in the ball park. I wont worry about it then until I get an accurate weight and balance.

[Bryan Cotton]

I found the old thread - check it out.
viewtopic.php?f=21&t=2933

[Murray Parr]

Thanks Bryan,

I will add my W&B info to the list once complete