Tail wheel size?

I noticed that the tail wheels of German fighters were quite large compared to other nation's fighters, adding drag and weight.
Anybody knows why?

spicmart said:

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I noticed that the tail wheels of German fighters were quite large compared to other nation's fighters, adding drag and weight.
Anybody knows why?

Click to expand...

For land planes, it depended on the runway surface: grass and soft surface - bigger wheel; hard runways - smaller wheel. Carrier based airplanes - "runway" very hard and the tail wheel was needed for only a few seconds during landing, and for a few minutes for taxiing and maneuvering on the carrier's deck (even on take off without catapult, the tail and tail wheel would come up after a very short run). That's why most carrier planes' tail wheels were very small and made of hard rubber (see the F8F above). The Brits and German widely operated from grass fields and thus needed bigger tail wheels. The Americans rarely operated from grass fields and thus had smaller tail wheels.

Hi,
I have heard similar reasoning. Specifically, when Brewster designed the F2A for the USN it had a small diameter hard wheel for operating off carriers, but when these planes were sold to Finland the tail wheel was replaced by a larger diameter inflatable tire, which was fixed in the down position since it was too big to retract in the space allotted for the smaller tire.

Pat


Finnish B-239


USN F2A-2

PS. I believe that the later derivatives of this plane designed for the RAF, Commonwealth, and Dutch East Indies also were fitted with the larger fixed, inflatable tires since they would be operated from various land base fields.

One reason for the solid rubber "deck tires" was blowouts. Hard deck landings could cause them and muck up timely deck movements. That's why when hooks were removed for land ops they would typically install pneumatics at the same time to help handling on coral gravel and Marston Mat airfields. (I've heard pilots complain about the rough ride of solid deck tires ... I know of several F6F/F4U solids floating about no one is saying they want to use ... as well as a short F4U tailwheel fork.)

The Germans tended to use larger tailwheels than others both because it helped "off-road" performance (yay bush planes) and some of their planes (like the 109 and 88) carried a larger percentage of aircraft weight on the tailwheel. This aft weight bias went a long way to prevent nose-overs on unimproved fields (which largely couldn't be prevented by pilot skill) but did make groundloops much more likely (relying on pilot skill to prevent). By comparison, the Spitfire carried more weight on the mains (thereby not requiring much of a tailwheel) and so was directionally very easy to control on the ground but would nose over if the pilot sneezed. (The Mosquito, on the other hand, carried more weight on the tail, German style.)

((( Now that I think about it, the weight bias was probably not so much a national design convention as much as an individual designer preference. Oh, well. )))

Thanks, gentlemen.

spicmart said:

I noticed that the tail wheels of German fighters were quite large compared to other nation's fighters, adding drag and weight.
Anybody knows why?

Click to expand...

Hello Spicmart,

The photographs you have there are a bit misleading. The FW 190 was physically small, but it was fairly heavy.
It was quite a bit heavier than the Spitfire or the Raiden that are also in your photographs.
The drag probably wasn't as bad as one would expect because the wheels tended to be partially retracted.
The FW 190 usually had more of the tire retracted than your photograph of a modern reproduction aircraft shows.
The tail wheel on the Me 109 is a bit of a longer story.
The Me 109 up through the Me 109E had a fixed tail wheel.
The Me 109F and early Me 109G had a partially retractable tail wheel with about half showing below the fuselage underside.
The later 109G gained some weight and needed a bigger tire in the back and the bigger tire would not fit into the same space so it became fixed down.
The photograph you have is the equivalent of a late G model and the tail wheel strut was extended to improve the ground angle at take off and landing.
The Me 109K had a tail wheel strut of about the same length but it was fully retractable behind a pair of doors.
Unfortunately they sometimes had mechanical problems so were fixed down despite the retract mechanism.

- Ivan.

Tis a big wheel though - 380 mm in diameter...