Quantcast

Metal skin for ultralight wing

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

stanislavz

Well-Known Member
HBA Supporter
Joined
Aug 21, 2016
Messages
643
Location
Lt
Just read this article :


WICHITA – The Chipper STOL, a two-place experimental amateur-built aircraft kit from Belite Enterprises, now has a metal wing option for $1,320 and 15 extra pounds.

According to company officials, the metal wing option reduces build time and drag and improves performance.


Wings have 113 square feet area or 10.5 m2 Minus 1.5 of fuselage area - 9m2 pf wing area or 18m2 total for cowering, or 18 x 0.8 14.4 m2 of metal skin, excluding control surfaces ?

And - 6.8 kg / 18m2 = 0.3777 kg/m2 or 0.14mm of aluminimum foil ?
Or 6.8/14.4 = 0.472 kg/m2 = 0.172mm of aluminium foil.

But - original fabric also weight, according to my math - no more than 0.4 kg/m2 / or 0.15 mm of aluminium foil..

So - adding this will yield ~ 0.3-0.32mm of skin..

Do my numbers looks right ?
 

stanislavz

Well-Known Member
HBA Supporter
Joined
Aug 21, 2016
Messages
643
Location
Lt
A metal skin can be load bearing, allowing less structure elsewhere.
I know, done this in theory in composite. But i do it by molding Front tube in D tube shape, loading skin with some stringgers etc.. But here it is totally dead weight. But still looks more like foil, but not sheet of 016" / 0.4 mm as minimal gauge.
 

proppastie

Well-Known Member
Log Member
Joined
Feb 19, 2012
Messages
4,703
Location
NJ
That is not an ultralight. .....ELSA......too heavy for Part 103
 

proppastie

Well-Known Member
Log Member
Joined
Feb 19, 2012
Messages
4,703
Location
NJ
You make the assumption that the weights reported are correct.
Perhaps there were changes to the second plane and that accounts for some of the weight discrepancy as regards skin thickness.
 

BBerson

Light Plane Philosopher
HBA Supporter
Joined
Dec 16, 2007
Messages
13,764
Location
Port Townsend WA
It was likely foil stuck over foam. Check to see if that Chipper had foam skinned wings. It said only fours hours to apply the foil. He probably had automotive wrap originally, from some of his designs I inspected at Oshkosh.
 

stanislavz

Well-Known Member
HBA Supporter
Joined
Aug 21, 2016
Messages
643
Location
Lt
Just another example. This is souricette wing. It looks like half covered with plywood already, for 10m2 wings. And for 1.2mm plywood you could cover whole wings with plywood for extra 10kg minus fabric weight for original one. Like 3kg.

So why it was not done in this way from start ?
 

Attachments

BBerson

Light Plane Philosopher
HBA Supporter
Joined
Dec 16, 2007
Messages
13,764
Location
Port Townsend WA
Usually plywood wings are covered with fabric anyway for protection and preventing cracked paint. The weight in front of the CG is desirable. Every pound counts. (10kg is 22 POUNDS)
 
Top