The first production aircraft with wingtip tanks?

[Conslaw]

It seems like as soon as WWII was over, wingtip tanks were the rage, I have been trying to find out what was the first production aircraft with wingtip fuel tanks. I found a picture of the second prototype of the F4U-4 Corsair fitted with wingtip tanks in March 1945, but no data on the test, and of course, this did not go into production. Was the first production aircraft with wingtip tanks

The P-80A?

 

[Tkdog]

Was just wondering this myself. Looking forward to the discussion.

 

[Capt. Vick]

I'm gonna say P-80, with no backing evidence

 

[Conslaw]

Here is a patent applied for in May 1944 by Clarence "Kelly" Johnson of Lockheed for an wingtip tank (underwing type), clearly like the P-80. The P-80's tip tank was different from most others as it was actually attached under the wing near the tip rather than bolted onto the far end of the wing. Multiple sources say the purpose for attachment in this location is to allow a 1,000 lb. bomb to be attached there instead of a fuel tank if necessary.

 

[PAT303]

What is the advantage of wing tip tanks?, seems weird to put fuel tanks as far away from the engine as possible.

 

[glennasher]

https://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=86

According to this, wingtip tanks supposedly added to the laminar flow of the wing and eliminated some drag. Kelly Johnson applied for a patent for those reasons, anyway,

 

[fastmongrel]

Don't have any information but wouldn't all the extra weight of wing tip tanks do horrible things to the roll rate.

 

[muskeg13]

If it wasn't the P-80, other possible candidates are the McDonnell F2H Banshee, Lockheed Constellation and the Lockheed P-2 Neptune

 

[Admiral Beez]

Don't have any information but wouldn't all the extra weight of wing tip tanks do horrible things to the roll rate.

Only if both were equalized. I imagine one full tank would do wonders for the roll rate, until you crashed.

 

[R Leonard]

Early F4Us had outer wing tanks of 63 gallons each without benefit of a wingtip tank system. These were later phased out of the design in favor of two 150 gallon drop tanks and increasing the capacity of the main tank.

 

[MIflyer]

I would say the P-80, although the TF-80C/T-33A probably was the first with integral wingtip fuel tanks. It did improve the aerodynamics for the same reason that winglets do.

The F-80 pilot's manual says it can be landed with one tip tank full and one empty - but it is not easy. This was a long standing problem with the T-33A. I recall that around 1977 our office at OC-ALC got into an argument with SM-AlC. SM-ALC said we needed to tighten the tolerances on the external tank pressure regulator to prevent that condition. Our response was that the tip tanks had built-in "sniffle" valves that worked exactly like the valve built into an automobile radiator cap. If the pressure exceeded a certain value the valve would open and bleed some off. To prevent one tank from remaining full and one going empty you needed to select a sniffle valve that was set for a similar value for each tip tank on an airplane - match them, which made it an airplane system problem. SM-ALC said the problem was the pressure going into the tanks, not what the sniffle valves bled it down to, which made it a pressure regulator component problem. So, over 30 years after the problem was identified, the USAF was still trying to figure out what to do about it.

 

[Conslaw]

What is the advantage of wing tip tanks?, seems weird to put fuel tanks as far away from the engine as possible.

Most of the aircraft coming out from about 1947 through the 50s had the wing tanks centered at the end of the wing. This gave the designer some options for managing airflow coming off the wings. they weren't necessarily lower drag, but might be in certain designs. In other aircraft, having permanently placed fuel tanks at the end of the wings simply was the only good place to put the fuel needed. The F9F did not have space in the fuselage for the fuel needed. The permanently attached wingtip tanks fit the bill. The Super Constellation needed the extra fuel to meet its range requirements, I suppose adding the tanks to the end of the wing solved the problem without a more involved redesign of the fuselage.

 

[SaparotRob]

I would say the P-80, although the TF-80C/T-33A probably was the first with integral wingtip fuel tanks. It did improve the aerodynamics for the same reason that winglets do.

The F-80 pilot's manual says it can be landed with one tip tank full and one empty - but it is not easy. This was a long standing problem with the T-33A. I recall that around 1977 our office at OC-ALC got into an argument with SM-AlC. SM-ALC said we needed to tighten the tolerances on the external tnak pressure regulator to prevent that condition. Our response was that the tip tanks had built-in "sniffle" valves that worked exactly like the valve built into an automobile radiator cap. If the pressure exceeded a certain value the valve would open and bleed some off. To prevent one tank from remaining full and one going empty you needed to select a sniffle valve that was set for a similar value for each tip tank on an airplane - match them, which made it an airplane system problem. SM-ALC said the problem was the pressure going into the tanks, not what the sniffle valves bled it down to, which made it a pressure regulator component problem. So, over 30 years after the problem was identified, the USAF was still trying to figure out what to do about it.

I have never heard of a sniffle valve. You have made my day.

 

[fastmongrel]

I have never heard of a sniffle valve. You have made my day.

Me neither I have heard of a Snifter or Snifting valve which is used on some steam locomotives to prevent a vacuum forming in the superheater circuit when the loco is coasting along with the regulator (throttle) closed.

 

[AMCKen]

https://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=86

According to this, wingtip tanks supposedly added to the laminar flow of the wing and eliminated some drag. Kelly Johnson applied for a patent for those reasons, anyway,

Similar to the endplates and other fences on wings to help direct the airflow? Keeps the underwing area free for disposable items.
Endplates on this one.

 

[glennasher]

Similar to the endplates and other fences on wings to help direct the airflow? Keeps the underwing area free for disposable items.
Endplates on this one.

You probably know a lot more about it than I do. I had literally just read that when I was looking into the P-80, and it came up here. You will note that I took no editorial position on the subject, because I just don't know.

 

[chipieal]

Only if both were equalized. I imagine one full tank would do wonders for the roll rate, until you crashed.

Was there a way to jettison the wingtip tanks on The P - 80? I only ask because as already mentioned, unless there was a system which allowed each tank to empty at a similar rate eventually the plane would become so destabilized as to be nearly impossible to control in a dogfight. And isn't agility the whole reason for a pursuit?

 

[GreenKnight121]

Was there a way to jettison the wingtip tanks on The P - 80? I only ask because as already mentioned, unless there was a system which allowed each tank to empty at a similar rate eventually the plane would become so destabilized as to be nearly impossible to control in a dogfight. And isn't agility the whole reason for a pursuit?

Here is a patent applied for in May 1944 by Clarence "Kelly" Johnson of Lockheed for an wingtip tank (underwing type), clearly like the P-80. The P-80's tip tank was different from most others as it was actually attached under the wing near the tip rather than bolted onto the far end of the wing. Multiple sources say the purpose for attachment in this location is to allow a 1,000 lb. bomb to be attached there instead of a fuel tank if necessary.

I would expect that, since the station was designed to carry a bomb, that it would have "stores jettison" capability. After all, one does not plan to load a bomb onto a station where it cannot be dropped.

 

[PStickney]

Was there a way to jettison the wingtip tanks on The P - 80? I only ask because as already mentioned, unless there was a system which allowed each tank to empty at a similar rate eventually the plane would become so destabilized as to be nearly impossible to control in a dogfight. And isn't agility the whole reason for a pursuit?

Yes, there was. And the tip shackles were used for bombs as well, but required some extra work from the Gun Plumbers - the wingtip vortices could cause the box fin assemblies on WW2 AN/ series bombs to unscrew themselves and fall off, which did not improve accuracy. The fins had to be pinned in place.
The 230 gallon centerline tanks can be jettisoned - there were 3 methods - a bunch of switchology and coordination to drop using the bomb release circuits, a Jettison Button on the Instrument Panel, and a couple of manual release levers on the front cockpit floor on the left side. The limit speed for dropping the tanks was 390 KIAS, with a recommended speed between 360 KIAS and 390.

 

[XBe02Drvr]

What is the advantage of wing tip tanks?, seems weird to put fuel tanks as far away from the engine as possible.

According to this, wingtip tanks supposedly added to the laminar flow of the wing and eliminated some drag

Similar to the endplates and other fences on wings to help direct the airflow?

Anything on the wingtip that impedes vortex generation; endplate, (good) tip tank, (better) or winglet (best) reduces drag significantly, (more than the parasite drag it adds). It reduces the energy that goes into vortices, and by reducing spanwise flow, thus improves laminarity and reduces skin drag, all of which improves the L/D of the wing as a whole.
Adding weight to the outer end of the wing, while reducing initial roll rate, actually reduces stress on the wing structure during high G maneuvers, as it reduces the concentration of weight in the fuselage and distributes it outward, reducing the bending moment.
Cheers,
Wes