(It still has the O-300 engine.) Would appreciate your thoughts and inputs. Thanks!
Matt
Auxiliary Fuel Pump?
Auxiliary Fuel Pump?
Am I making a mistake, if I don't install an auxiliary, electric fuel pump into a Sedan being rebuilt? (It still has the O-300 engine.)
Would appreciate your thoughts and inputs. Thanks!
Matt
(It still has the O-300 engine.) Would appreciate your thoughts and inputs. Thanks!
Matt
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Nathan K. Hammond
- Posts: 2371
- Joined: Wed Nov 17, 2004 00:22
- Location: Danville, KY (DVK)
- Contact:
Thank you guys!
My worries began to develop, when a friend recently totalled his biplane (fuel tank in fuselage), during an off-airport emergency landing caused by a failing mechanical pump. (It is assumed that the electric auxiliary pump was not switched on.) Many pilots have since expressed the opinion that you should always use the booster pump for take off and approach, no matter which airplane, high or low wing.
Then I remembered that even the little Cessna 150s have that pump, in spite of being high-wing airplanes. So, why should the Sedan be safe without one....? Is there a physical reason (different fuel system layout) why a pump is not needed? Or was that safety net sacrificed in favor of simplicity and low cost, back then?
Still hoping for more votes, opinions and background information.
Matt
My worries began to develop, when a friend recently totalled his biplane (fuel tank in fuselage), during an off-airport emergency landing caused by a failing mechanical pump. (It is assumed that the electric auxiliary pump was not switched on.) Many pilots have since expressed the opinion that you should always use the booster pump for take off and approach, no matter which airplane, high or low wing.
Then I remembered that even the little Cessna 150s have that pump, in spite of being high-wing airplanes. So, why should the Sedan be safe without one....? Is there a physical reason (different fuel system layout) why a pump is not needed? Or was that safety net sacrificed in favor of simplicity and low cost, back then?
Still hoping for more votes, opinions and background information.
Matt
Matt,
The airplane was certified without one, so none needed.
In fact, if you decided to add one, you or your mechanic would have to get special certification (here in the US its a 337 form) to install a boost pump.
Major thing if you are worried is to check the hose going to the carb and do a "flow check" making sure that you have good fuel flow. Believe there is a measurement of how much pressure there should be at the carb and that could be checked as well.
Joe A
The airplane was certified without one, so none needed.
In fact, if you decided to add one, you or your mechanic would have to get special certification (here in the US its a 337 form) to install a boost pump.
Major thing if you are worried is to check the hose going to the carb and do a "flow check" making sure that you have good fuel flow. Believe there is a measurement of how much pressure there should be at the carb and that could be checked as well.
Joe A
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sedanpilot
- Posts: 113
- Joined: Fri Nov 19, 2004 03:12
- Location: Alaska
- Contact:
Aux Pump
Matt: In the Sedan, an Aux pump is not necessary or approved because the wing is quite high relative to the carburetor even in a climb attitude. Some airplanes do need a pump because of the way they are laid out, even high wing airplanes.
Burl does do a header tank mod for the Sedan and because if you slip for a while at the end of a flight and don't have much fuel, it can run outboard if the uphill tank doesn't have much fuel either. I like the Aux tank idea myself, but I think a fuel pump just adds weight and another thing to fail and cost money.
Burl does do a header tank mod for the Sedan and because if you slip for a while at the end of a flight and don't have much fuel, it can run outboard if the uphill tank doesn't have much fuel either. I like the Aux tank idea myself, but I think a fuel pump just adds weight and another thing to fail and cost money.
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Nathan K. Hammond
- Posts: 2371
- Joined: Wed Nov 17, 2004 00:22
- Location: Danville, KY (DVK)
- Contact:
Carburetors are set for around .5psi head pressure; adding a fuel pump can create 45psi and physically push the needle off the seat, flooding the venturi. Like Joe and Dave have said; adding an boost pump will create more problems than it could ever help.
Using a boost pump on takeoff and landing are good practice, as long as the POH calls for it. In a Bonanza you don't use the boost pump on takeoff. Then others you use it for everything; T/O, landing, switching tanks, above 8,000msl, below 12psi fuel pressure etc... No need to worry, just educate yourself.
A scary realization I had, is a boost pump won't always bring the engine back online if you run a tank dry. Fly smart!
nkh
Using a boost pump on takeoff and landing are good practice, as long as the POH calls for it. In a Bonanza you don't use the boost pump on takeoff. Then others you use it for everything; T/O, landing, switching tanks, above 8,000msl, below 12psi fuel pressure etc... No need to worry, just educate yourself.
A scary realization I had, is a boost pump won't always bring the engine back online if you run a tank dry. Fly smart!
nkh
7AC-5691
Super 85-12F @ DVK
Super 85-12F @ DVK
Interesting and convincing info. I will stick to the proven design. And I'll talk to Burl regarding the header tank. At the moment, would like to change as little as necessary, though, in order to finally get our plane in the air, again, soon.
Thank you very much, Joe, Dave and Nathan! I appreciate your help and send best regards,
Matt
Thank you very much, Joe, Dave and Nathan! I appreciate your help and send best regards,
Matt
Fuel pump/header tank
The header tank is usually only necessary with Burl's Cessna 170 fuel valve mod where each tank can feed the engine independently. There are at least two reasons for this 170 fuel valve mod, one being the use of a modern fuel valve that can be serviced and/or replaced. This reason is somewhat less valid with the use of Burl's replacement original fuel valve. Another reason would be the ability to draw from each tank independently as well as both tanks. This can be a real plus with the 180 lycoming conversion where fuel management is critical with the increased fuel burn. This is the main reason that I am going with the 170 fuel valve/header tank mod. If you are trying to stick with the original configuration and/or dont feel the need to draw independently from each tank, I would stick to the original system, with the use of burl's replacement fuel valve and possibly a new STC/PMA gascolator from steve's aircraft. If Burl gets his AUX fuel system approved in the future it will most likely require the use of the header tank and 170 fuel valve. If one is looking for more fuel, I believe there is a factory drawing that provides for an approved aux fuel system that uses a tank underneath the rear seat along with an electric transfer pump. I am not sure of the capacity, but I think it is somewhere in the neighborhood of 20-30 US gallons.
Thats my thoughts on the subject
Tom
Thats my thoughts on the subject
Tom
Thanks for more good info, Tom!
Your post reminded me of a Sedan in our gallery that does have an additional 19 gal under-seat fuel tank: http://www.n1331h.com/sedan_gallery/15ac-338_n1308h_20
I have just emailed the owner and hope, he will post his thoughts and experiences with the modification here on the forum.
Matt
Your post reminded me of a Sedan in our gallery that does have an additional 19 gal under-seat fuel tank: http://www.n1331h.com/sedan_gallery/15ac-338_n1308h_20
I have just emailed the owner and hope, he will post his thoughts and experiences with the modification here on the forum.
Matt
Tom and Matt,
Even more important is that with the "N" number of the airplane, now anyone can go to the FAA and get the CD with the STC and 337 data on this airplane and see the approval method. If its a factory tank and system then it very well may have the drawing number which would be a big help!
Joe A
Even more important is that with the "N" number of the airplane, now anyone can go to the FAA and get the CD with the STC and 337 data on this airplane and see the approval method. If its a factory tank and system then it very well may have the drawing number which would be a big help!
Joe A
Aux Tank
Joe
Since the aux tank is a factory drawing no STC or 337 is required, just a log book entry. The factory did all of the testing and engineering and the FAA approved it as part of the aircraft type certificate data. As far as getting a copy of these factory drawings, I would start by calling the factory in Alaska @ (907)688-3715. Burl would have or could print you a copy of these drawings. Going to the STC/337 data would give you no information on this, you could go to the log book to get the drawing number.
Tom
Since the aux tank is a factory drawing no STC or 337 is required, just a log book entry. The factory did all of the testing and engineering and the FAA approved it as part of the aircraft type certificate data. As far as getting a copy of these factory drawings, I would start by calling the factory in Alaska @ (907)688-3715. Burl would have or could print you a copy of these drawings. Going to the STC/337 data would give you no information on this, you could go to the log book to get the drawing number.
Tom
Re: Aux Tank
Hi Tom,49_sedan wrote:Joe
Since the aux tank is a factory drawing no STC or 337 is required, just a log book entry. The factory did all of the testing and engineering and the FAA approved it as part of the aircraft type certificate data. As far as getting a copy of these factory drawings, I would start by calling the factory in Alaska @ (907)688-3715. Burl would have or could print you a copy of these drawings. Going to the STC/337 data would give you no information on this, you could go to the log book to get the drawing number.
Tom
Somebody in the group here might jump up to correct me, but I'm fairly confident that just because the factory made a drawing for something doesn't mean it's automatically approved for a given model aircraft.
I am certain that in AS A-802 for the Sedan, there are two examples of what you might be referring to: Miscellaneous 601 (Levens Bro's left-side door) and 602 (Sevdy crop sprayer). Those are on the Aircraft Specification and so don't require a 337 because neither is an alteration. An airframe logbook entry would be professional bookkeeping, but even that's probably not strictly required. To reiterate: a 337 is not required for the Levens Bros door or the crop sprayer because neither is an alteration to A-802. For example: you buy a Sedan with no door on the left. You install Levens Brother's door according to Dwg 11A, cutting steel, removing the window, adding framework, etc, etc...this is not an alteration.
I don't see anywhere in A-802 that says anything about a third fuel tank, though, or allowance for a capacity other than 36 gallons. A factory drawing for a 'rear' tank in 15AC would be very intriguing, but I can speak from direct professional experience that a given assembly can go out the door with 500 parts, yet there are 700 drawings for it in the filing cabinet for all sorts of reasons. There are likely other 15AC factory drawings out there that never shipped in the final product, but unless they're in the Specification, they're probably only good for greasing a field approval.
Along those lines, though, I'd enthusiastically encourage anyone with approved or acceptable data that could make the Sedan more flexible and sought-after to step up with anything that could facilitate a field approval or fast-track an STC.
And Joe's absolutely right, we should simply look at how N1331H got its field approval for the rear tank and model a similar FSDO request through your friendly IA.