Did PA-14s originally have header tanks? Should they with a 0-320?

My best friend just bought a "project" PA-14 with a 0-320 up front.
I noticed that it does not have any header tanks and it still has the old original fuel tanks with only one line on one of the tanks and the right or left fuel valve.
Did they originally have header tanks ? Should it have header tanks with the 0-320 ?

look in the parts book, on a -12 it was optional

All I have is a 18 parts book which shows two header tanks. Heck even my C-90 converted J3 /PA-11 had a header tank for the single wing fuel tank.
I was thinking that the extra fuel required by the 0-320 as compared to the original 0-235 might make headers a good idea.
I know there are some larger tank STCs with more fuel outlets from the tanks and vented caps that supposedly do-away with the need for header tanks in a modified PA-14.

Alex, where ya been? My 150 HP -12 with Atlee Dodge 30 gal tanks does not have a header. There is an outlet port at the front of the left-hand tank, IAW the tank STC. All 3/8" lines. Never any fuel flow problems.

Another thing to think about----my 1954 Cessna 180 just has one outlet per tank towards the rear and no header tank.

I do not think my -14 had header tanks with an O-320. I had the original fuel system with two ports on one tank and one port on the other (I can't remember which was which). I did a lot of maneuvering on the one port tank and I never had a fuel flow issue or a hiccup.

Gordon,
The local hospital & clinic tried to kill me via mus-diagnosis this last summer.
Finally when up the hwy to see a real doctor and was wheeled into surgery. So I lost the whole summer.
All is fine now.
180 Marty I was reading some STCs and there are a few that use a Cessna fuel valve with the BOTH setting instead of the old Piper right or left. The STC notes that the BOTH setting cuts out the need for a header tank.

This all makes me wonder why they decided that the Super Cub needed headers???

Welcome back Alex. In my opinion, unless the header tank is really needed for some reason, it's best to leave it out. A couple of reasons - not the least of which is a gallon or so of gas in one's lap. Also, if running a tank dry, whether deliberately or not, a header tank will increase the amount of time required to get gas to the carb. If at low altitude (I know, that shouldn't happen), that could matter.

My old Cubs with headers had two h- tanks both fore and aft. So when you flipped to the other tank, you had instant fuel from the other H-tank up the line.

Alex Clark said:

My old Cubs with headers had two h- tanks both fore and aft. So when you flipped to the other tank, you had instant fuel from the other H-tank up the line.

Click to expand...

Interesting - I'd be curious to know how that is plumbed for "instant" fuel. Thanks - -

Alex Clark said:

My old Cubs with headers had two h- tanks both fore and aft. So when you flipped to the other tank, you had instant fuel from the other H-tank up the line.

Click to expand...

No, no they just allow SOME (extra)time before you relise you are doing something dumb, and the noisy thing up front quits being noisy

think out loud....

isn't a header tank, kinda like a high interest credit card... allowing you to do something NOW, BUT at a HIGER cost in the long term/time???

(good thing if you only use 1/3 of capacity.. but bad if you expect to use it ALL... and get more)

Also, if running a tank dry, whether deliberately or not, a header tank will increase the amount of time required to get gas to the carb

Click to expand...

Interesting - I'd be curious to know how that is plumbed for "instant" fuel. Thanks -

Click to expand...

Nope and Yeap.

http://www.supercubproject.com/downloads/PA-18_Information_Manual.pdf (diagram PAGE 9)

My point being that when you run dry from one side and then switch to the other tank, there is no extra lag time waiting for something to fill-up. The headers on both sides are upstream from the fuel selector valve. So usually there is fuel in the two lines right up to the valve. If you run one system dry,,, the valve is moved over to the other tank setting, then fuel only needs to flow through the two feet of fuel line to the gasolator and carb. I have run tanks dry on a few occasions in Super Cubs, A PA-12 and even my old J5-125 which had a 18 fuel system. The engine just dies while in flight and then starts right back up when I flipped over to the other tank setting. NOT THAT IT IS A GOOD IDEA, but circumstances dictated that I do that on 4 or 5 occasions.

As for the original idea of their installation, it was to act as a sort of 2 quart fuel slush-fund in case the tank being used became un-ported during maneuvers. Maybe because they thought of the PA-18 as a utility type aircraft likely to be doing things like crop-dusting and cattle herding. On the other hand maybe they figured the family cruiser and other planes as more of a point A to B transport.

I was thinking of the header as being plumbed between fuel valve and carburetor. But looking at the drawing I see what you mean. Thank you!

Alex Clark said:

Nope and....

Click to expand...

Yes...

ONLY X amount of 'head'(source height ~= pressure) & per volume deliverable for line size...

if ONLY a direct line, then all HEAD pressure is ~instantly available at the destination...

but if EMPTY header tank needs refilling at SAME time, it WILL require more TIME, UNtill header tank is full, and only then, will full head pressure(& flow volume) be available again at destination...

Yes, except......

The schematic that Alex posted is such that if there is fuel in a tank, it's respective header tank would be full. There is no valve between each main tank and its respective header, and the headers are vented back to their respective main tanks so that airlock would not occur.

That said, I still would not want to add header tanks without a compelling reason. Added weight and complexity for no gain. In the 40+ years I've had this same -12, it has never had a header tank and I have never once had an unporting problem.

Gordon Misch said:

Yes, except......

The schematic that Alex posted is such that if there is fuel in a tank, it's respective header tank would be full. There is no valve between each main tank and its respective header, and the headers are vented back to their respective main tanks so that airlock would not occur.

That said, I still would not want to add header tanks without a compelling reason. Added weight and complexity for no gain. In the 40+ years I've had this same -12, it has never had a header tank and I have never once had an unporting problem.

Click to expand...

most header tanks are not vented properly, -18 is "vented" to lower front fitting... making it a poor vent, and a poor 1/4" fuel line...

I didn't bother to look at what alex posted.... just in general it not true..

Yes..

Click to expand...

Mike:
I respectfully disagree.

They are basically two separate fuel systems from the valve going upstream. So the empty header, or upstream fuel lines for that matter, are not being re-filled at all when you switch tank settings. they only thing being refilled is the fuel line from the valve to the gasolator and carb, since the new tank setting is basically a direct line at least to the valve.

However, IF there was a BOTH setting on the valve and I run one side dry while on a right or left only setting, and IF there were two headers in that type of system with one now being empty, Then I could see a problem because the BOTH setting would suddenly allow a cross feed and the empty header tank would be filling up via back-flow. That would (could) indeed cause a reduction in head pressure.

I cannot figure out why they only used the little 1/4 inch line for the front corner of the tank and not just have a 3/8th inch line coming off the front and back of both tanks and then have a both setting on the fuel valve.

I post a copy of a page from a PDF diagram and post it like a photo. It lets me highlight it, but not save as a photo or image.

Anyway, it looks like the answer to my question is that they probably did not have headers in the original system for the PA-14 Family Cruiser.

The forward or left header is positioned to always be above the carb. Long extended steep climbs or landings on steep hillsides make it a good option. Most people never fly to those extremes. Piper designed it so you could. Saying you've never had a problem with your headerless system doesn't mean you won't. What was the engine originally installed on the 14? By changing the fuel feed requirements with a bigger engine, the original fuel system may be inadequate.

What is the purpose of the 1/4" vent line? Remember that the headers should always be full unless you are running out of fuel. IF you run the tank dry or if somehow air gets introduced into the header tank, it must be allowed to escape. The 1/4" line from the top of the header to it's respective main tank is there only to bleed the air from the header.

nanook is the only person here who has approached the reason for the header tanks.

The following is from CAR 3, the certification basis of the PA-14. http://specialcollection.dotlibrary.dot.gov/Document?db=DOT-CARS&query=(select+72)

03.422 Fuel system operation.
03,4220 Fuel flow rate.
The ability of the fuel system to provide the required fuel flow rate and pressure shall be demonstrated when the airplane is in the attitude which represents the most adverse condition from the standpoint of fuel feed and quantity of unusable fuel in the tank.During this test fuel shall be delivered to the engine at the applicable flow rate (see §§ 03.42200,03.42201, and 03.42202) and at a pressure not less than the minimum required for proper carburetor operation. A suitable mock-up of the system, in which the most adverse conditions are simulated, may be used for this purpose. The quantity of fuel in the tank being tested shall not exceed the amount established as the unusable fuel supply for that tank as determined by demonstration of compliance with the provisions of § 03.4221 (see also §§ 03.423 and 03.5222), plus whatever minimum quantity of fuel it may be necessary to add for the purpose of conducting the flow test. If a fuel flow meter is provided, the meter shall be blocked during the flow test and the fuel shall flow through the meter by-pass,

03.42200 Fuel flow rate for gravity feed systems.
The fuel flow rate for gravity feed systems(main and reserve supply) shall be 1.2 lbs. per hour for each take-off horsepower or 150% of the actual take-off fuel consumption of the engine, whichever is greater.

To answer Alex's question of "should there be header tanks in a 150 hp PA-14?" we must look at the STC which approved the installation of the engine, since the original PA-14 engine was an 0-235. OR is there a subsequent STC which allows the removal (if they were originally installed) of the headers.

This note is part of the TC: (This would only be applicable to the 0-235 engine installation) The 0-320 must be addressed separately.
NOTE 2.
The following placards must be displayed on the instrument panel in full view of the pilot:
(a)*
(b)*
(c) "Right tank should be used in level flight only."

With this note I suspect that there is NO header tank connected to the right tank. Perhaps there is one for the left tank? OR there is sufficient fuel flow so that one is not needed.

I will add that if anyone has access to Piper's original fuel flow testing results, it may be possible to determine that there was adequate fuel flow on the original tests to cover the flow requirements of the 0-320. I suspect that FAA engineering in Anchorage has access to this data.

There is a common caution via word of mouth that the right tank in a PA-18 should only be used in level flight.

Yet I cannot find this caution, or any other restriction on use of the right tank, in the Super Cub POH.

Eddie,
This is from the TC: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/ab203ab0e89895af862572090071f7cd/$FILE/1A2.pdf

102. Fuel tank, 18 gallons (optional) right wing +16 lb. (+25) Net weight change for installation. Installed in accordance with Piper Dwg. 12458, 12544 and 12778. Header Tank, Piper Part No. 12837 also required.

There are no notes which indicate that what you have heard is correct. It would appear that when the second optional fuel tank is installed with it's header tank that there is no requirement for it's use in level flight only. There are some airplanes where this is a requirement. Your PA-18 came with two tanks installed so unless there is a placard saying otherwise (not indicated in the TC) either tank is usable for TO.

Pete,
Yet the belief exists with many to the contrary. My IA cautioned me about use of the right tank. I never take off or land on right tank only, however, to err on the side of caution.

I think all this stems from the fact that the right tank, unlike the left, does not have a forward outlet.

I wonder if anyone here has experienced problems with right tank feed during descent or landing.

I think all this stems from the fact that the right tank, unlike the left, does not have a forward outlet

Click to expand...

Correct, at least in the PA-12.

The first PA-18s(95hp) only had a left side tank like a PA-11 and the right tank was optional.

The PA-14 in question is also placarded with the level flight only for the right tank. Of course it is currently headerless and only has one fuel line from that tank. Although there are a LOT of odd things on this plane that are not as they should be.

Piper only made something like 232 of the originally underpowered PA-14s. Piper was basically competing with itself and the PA-20 Pacer took the 4 seat market.

Long extended steep climbs or landings on steep hillsides make it a good option.

Click to expand...

I've never been able to unport in a steep climb, but can do so in a deliberate steep descent if right tank only is selected. But in that case a little bit of nose-up makes it noisy again. I should try a steep climb with low fuel level. Steep beaches - well, just be sure the uphill tank is selected.

Has anyone unported from the right tank in a PA-18 during a normal descent and approach to landing?

My PA-18 is not typical in that it has two fuel valves and two aux tanks. I can select off-main-aux on each valve. Thus I have a both option.

Eddie, your airplane appears to be different in it's fuel system. Without knowing the details of your system, it might be good to know if your extra tanks are auxiliary tanks or supplemental tanks. There is a difference which has to do with the certification requirements. An auxiliary can be used for take off and a supplemental can not. An auxiliary has fuel flow requirements.

Originally pa11 didn't have a front header tank. But after a couple of mysterious flame outs on long decents they figured out that under a half tank that all the fuel was forward of the only tank outlet in the rear. Cub Club story of one 11 in the bottom of the Gulf of Mexico that pilot never know why it quit till he read years later about the 11 needing a front header tank

Glenn

I only feed from the auxs in cruise. They only have one outlet each and no header.

skywagon8a said:

Eddie, your airplane appears to be different in it's fuel system. Without knowing the details of your system, it might be good to know if your extra tanks are auxiliary tanks or supplemental tanks. There is a difference which has to do with the certification requirements. An auxiliary can be used for take off and a supplemental can not. An auxiliary has fuel flow requirements.

Click to expand...