Fw 190 partly exposed tailwheel and lack of (mostly) outer landing gear doors

[paradoxguy]

Perhaps I have too much time on my hands or am too feng shui-oriented, but I am curious that the Fw 190 line had a mostly, but not completely, retractable tailwheel and most of them, with the notable exception of Fw 190A-6, did not have outer covering doors for the main landing gear. Similarly the Bf 109 line did not incorporate outer landing gear doors and completely retractable tailwheels until the Bf 109K-4, the last model, and even then many of the K's had their landing gear doors removed and their tailwheels locked in down position in the field. Similarly to the Fw 190, the Bf 109F-series, and I understand some of the early Bf 109G-series, incorporated a partly retractable uncovered tailwheel. In comparison, almost all American fighters, and most post-1943 British and Japanese fighters (including the A6M Zero which was flying since 1940), and the latter-day Italian fighters had completely retractable enclosed tailwheels and outer covering landing gear doors.

I am thus curious why did Kurt Tank not incorporate a fully-retractable and enclosed tailwheel at some point for the Fw 190 line, even the Fw 190D-series and the Ta 152, the evolutionary pinnacles of the Fw 190. Did Tank believe the advantages (less drag, protection from the elements) of a fully retractable, enclosed tailwheel did not warrant the additional complexity of the mechanism? Would a completely retractable tailwheel have caused unacceptable re-design of the tail unit? Was the tailwheel sufficient for support of the Fw 190/Ta 152 simply too large for complete retraction? Noting that many of the Bf 109K-4's had their tailwheels locked in down position in the field, was the mechanism for a completely retractable tailwheel considered unreliable in daily operations?

Similarly, did Kurt Tank and Wilhelm Messerschmitt believe for most of WWII that the benefits of outer cover doors for the main landing gear in their fighters did not warrant the additional complexity of mechanism, or did they simply lack reliably-operating outer doors until near war's end (noting that the Bf109K-4 had outer doors removed in the field)?

Thanks,
PG

[Catch22]

I cannot comment on the tail wheel, but the early Fw 190s DID have main gear covers, but they were removed and deleted from future versions because of maintenance issues. I believe they collected a lot of dirt and grime and were just generally inconvenient. The Ta-152 did have main gear covers.

[A4K]

With Cory... purely a matter of practical maintainance (IMO). Have a few photos of Fw 190F-8's operating in the snow with even the main wheel covers removed for this reason, only the upper portion covering the leg being retained.

Interesting that the Ta 152 series reverted back to having full main gear doors. The open tail wheel arrangement could possibly be explained by a lack of practical operating space (just my guess)

[Milosh]

On late model 190s the ETC rack interfered with the operation of the doors and so were not fitted. The rack had to be moved forward to help with the CG.

I would say you are correct A4K on the lack of space.

Can be seen in this Bentley drawing, http://www.albentley-drawings.com/images/FW190A5F.jpg

[A4K]

Originally Posted by Milosh

On late model 190s the ETC rack interfered with the operation of the doors and so were not fitted. The rack had to be moved forward to help with the CG.

Good point mate, and you're exactly right... (I'd forgotten about that! - DOH! )

[paradoxguy]

Originally Posted by Milosh

On late model 190s the ETC rack interfered with the operation of the doors and so were not fitted. The rack had to be moved forward to help with the CG.

I would say you are correct A4K on the lack of space.

Can be seen in this Bentley drawing, http://www.albentley-drawings.com/images/FW190A5F.jpg

Thanks for the responses so far, which made me realize that the Germans were operating from crude airfields in many instances, which probably made the doors a hindrance for maintenance.

I understand that lack of space likely initially resulted in the partly retractable tailwheel, but I am curious why the tail unit could not be enlarged eventually as the Fw 190/Ta 152 line evolved over 4-5 years to accomodate a fully-retractable tailwheel, as the Bf 109 did with the K-4.

[Milosh]

Originally Posted by paradoxguy

Thanks for the responses so far, which made me realize that the Germans were operating from crude airfields in many instances, which probably made the doors a hindrance for maintenance.

I understand that lack of space likely initially resulted in the partly retractable tailwheel, but I am curious why the tail unit could not be enlarged eventually as the Fw 190/Ta 152 line evolved over 4-5 years to accomodate a fully-retractable tailwheel, as the Bf 109 did with the K-4.

The 109 had troubles with its tail wheel retraction and was locked in the down position very often. There was also late model 109s with extended tail wheel struts, which did not retract.

The 190 got an increase in vertical tail width which is very easy to do. An increase in height to accommodate the extra distance for a fully retractable tail wheel is harder to do. The semi exposed tail wheel could act as a bumper in a wheels up landing.

Don't forget about the KISS factor.

[paradoxguy]

Originally Posted by Milosh

The 109 had troubles with its tail wheel retraction and was locked in the down position very often. There was also late model 109s with extended tail wheel struts, which did not retract.

The 190 got an increase in vertical tail width which is very easy to do. An increase in height to accommodate the extra distance for a fully retractable tail wheel is harder to do. The semi exposed tail wheel could act as a bumper in a wheels up landing.

Don't forget about the KISS factor.

Thanks for the additional explanation, I understand the situation better about the Fw 190 tailwheel. I knew that the Bf 109K-4 had problems with tailwheel retraction and thus many had their tailwheel locked in down position. I'm now curious if other fighters with fully-retractable tailwheels, such as the P-51, P-47, late Mk Spitfires, Ki-84 Hayate, K-61 Hien, and Macchi MC-205 had similar problems; I don't recall the references I've read indicating as such. Regardless, I know I may seem awfully focused on a small issue, but the situation just captured my curiosity and I had to try to satisfy it.

I searched on Google but could not discern the contextual meaning of KISS factor, so I'll bite--I'd be appreciative if you could edify me on the term.

Thanks to all again who chimed in.

[vikingBerserker]

Keep It Simple Stupid

[MikeGazdik]

Regardless of the weight and design changes, I still don't understand why it wasnt incorporated into the designs of these two planes. Im sure fully covering the main gear and retracting the tail wheel would have to add up to 10mph additional speed at the least.

I will say I am sure it was easier on the American aircraft. They all are generally larger airframes than the European fighters.

[farmersboy]

In the FW190 A8 aircraft handbook it states "when it is retracted, approximately one half of the tailwheel remains exposed and so can serve as an emergency tail skid".

When you look at the construction of the tail unit and how much of it is taken up with the mechanism for the tail wheel you can see why it was never intended for it to be fully retracting, and to be honest the drag imposed by half a tailwheel would be so minor as to not be worth worrying about.

[A4K]

Originally Posted by farmersboy

In the FW190 A8 aircraft handbook it states "when it is retracted, approximately one half of the tailwheel remains exposed and so can serve as an emergency tail skid".

Wow! I've never heard that before! Thanks FB!

Welcome to the forum too!

[paradoxguy]

Originally Posted by farmersboy

In the FW190 A8 aircraft handbook it states "when it is retracted, approximately one half of the tailwheel remains exposed and so can serve as an emergency tail skid".

When you look at the construction of the tail unit and how much of it is taken up with the mechanism for the tail wheel you can see why it was never intended for it to be fully retracting, and to be honest the drag imposed by half a tailwheel would be so minor as to not be worth worrying about.

That's a great find! It explains in one sentence why the Fw 190/Ta 152 likely did not have completely retractable tailwheels. Thanks so much and yes, welcome!

[Graeme]

Originally Posted by farmersboy

and to be honest the drag imposed by half a tailwheel would be so minor as to not be worth worrying about.

Interesting point. In fact looking at these drawings I'm surprised that they bothered at all. It seems to be a lot of effort with elaborate pulleys and cables connected to the main gears for what, 260mm of retraction?

[Milosh]

Originally Posted by farmersboy

In the FW190 A8 aircraft handbook it states "when it is retracted, approximately one half of the tailwheel remains exposed and so can serve as an emergency tail skid".

Thanks for the confirmation that the tail wheel acted as an emergency tail skid.

The semi exposed tail wheel could act as a bumper in a wheels up landing.