Posted: Fri Feb 27, 2004 6:50 pm
I guess I don't understand just what you meant by "dirivation of the C-120/140 fuel system". I assumed that you were referring to line size,as per your comment "...needs larger fuel lines...". I just checked a friend's A model IPC & it lists the same size fittings so I assume that it also has 3/8" OD lines. In my opinion,larger lines would not eliminate the potential for airlocking the lines due to the high point at the top of the front door post.gahorn wrote:My understanding is the ragwing fuel system is a derivative of the C-120/140 fuel system and has insufficient fuel flow for the C-145/O-300 engine. So a pump is required equipment for all stages of flight. (Just because a 337/field approval exists for another example of the airplane doesn't mean it was issued/approved knowlegeably.)
The ragwing needs larger fuel lines to provide adequate head pressure for a gravity system to comply with certification rules.
I'm curious if the 120/140 routes the lines down the front door post as does the ragwing 170. Maybe that's what you mean by "derived" and "descended"? That routing seems to me to be kinda foolish on Cessna's part--why design a high point in the system & then have to add a fuel pump because of it. If the line routing is the same in a 120/140,I don't feel line size is an issue--seems like the 120/140 would have the same potential for airlock as does the ragwing 170,regardless of lesser fuel flow. If that were the case it follows that cessna would have installed a fuel pump on the 120/140 as they did on the ragwing 170.
Eric