RCU Forums - View Single Post - 2 fuel tanks?
View Single Post
Old 02-19-2010 | 06:28 PM
  #15  
Lnewqban's Avatar
Lnewqban
 
Joined: Apr 2007
Posts: 4,057
Received 0 Likes on 0 Posts
From: South Florida
Default RE: 2 fuel tanks?

ORIGINAL: opjose


ORIGINAL: LNEWQBAN

I believe the problem with this set up is greater changes in the pressure that the carburetor sees for nose up and nose down attitudes.
For level flight, there is no problem beyond the added weight.
That would be true if fuel were compressable. Most liquids are not. It is the air ( or lack of it ) in the tanks which does this.

A properly plumbed system would incur no additional problems. e.g. plumb it like a Heli's header tank.

A header type plumbing arrangement, which is what should be used, only pressurizes or vents the very last tank in the chain.
So it is not much different from a pressure standpoint, from running a single tank.

That is true regardless the compressibility of the liquids or gases inside the tanks and hoses.

That is the only reason for which the fuel tank is located right behind the firewall, instead of at the CG.
The change in trim during flight is a compromise for good functioning of any carburetor.

A common form of Bernoulli's equation, for any fluid at rest (velocity = 0), is:

H + (P/Density) = constant

Where:
H is the height of the column of fluid above a point
P is the static pressure at a point

http://en.wikipedia.org/wiki/Bernoulli%27s_principle
Attached Thumbnails Click image for larger version

Name:	Ql35103.jpg
Views:	20
Size:	57.1 KB
ID:	1382598   Click image for larger version

Name:	Rp43178.jpg
Views:	24
Size:	50.1 KB
ID:	1382599