Tail Wheels

[05564]

Hello everyone! After viewing this fine web-site for several years , I have finally decided to register. First I would like to thank Scott for his great devotion to a subject we all seem to love, B-17's and B-25's. Second after visiting many other warbird web-sites, seeing how some of them are run , it's no contest. Scott you have a winner here. Third , I have a question? After perusing my new edition of Final Cut for the umpteenth time , I noticed something. Could the tail wheel on a B-17 be locked in differant postions. Some photos show the wheel almost perpendicular with the ground , while other photos show the wheel at differant degree angles, all of the same plane. At times the tail of the plane almost touches the ground , while other times it's quite off the deck. Thanks in advance for any help to this question.

[aerovin2]

Thanks much for the words of encouragement....that means a lot as I'm just now trying to find a good reason to work up a B-25 update.

As for the B-17 tailwheel...I believe it only locks straight aft (similar to the DC-3) and when it is unlocked it is free swiveling. What you are seeing with a cocked tailwheel is the result of the airplane turning and the wheel never straightened after the turn. Normally the airplanes would be parked with the tailwheel unlocked in case the airplane is towed.

[DryMartini]

Scott, I took the question differently.

First, you are correct in that the tail wheel
castering can be locked in one position - straight.

Next, the question sounds like whether the tail gear
can be stopped at various points in the retraction cycle.
The answer is "No", the gear is either full up
or full down. The variances you are seeing may be related
to weight loading and perspective. (Since the retraction
is electrical, and I suppose you can pull a fuse or something
during the cycle - there is no indicator in the cockpit for
"Tail wheel 1/2 down" - Just "Up/Down").
There is an oleo strut which gets compressed under the
weight of the aircraft, so a heavily loaded B-17 may look
like its tail is just off the ground. Maybe that is what
you are seeing 05564? (great name, BTW)

[Second Air Force]

Also, sometimes the oleo strut is under- or over-serviced and this would cause a different ground clearance at the back end of the airplane.

Scott

[05564]

Thanks all for clearing that up . I just knew I would find the answer on here with all the knowledge you guys have. Yes the name comes from my favorite movie , that started it all for me , my love for anything B-17.

[pokryshkin]

Dear Sirs and Ms.,

The answers so far are in line with everything I've seen about B-17s:
The tailwheel is free-swivelling, only locks straight back (mainly for takeoff), and would compress at different levels with different loads at different locations, depending on how far aft the load was, of the center of gravity and/or center of balance.
If some equipment or supplies have or had been loaded in the rear, this would naturally compress the tailwheel oleo strut further and the tail would sit lower to the ground.
The angles of turn would come from where and how the airplane had turned while taxying and/or turning into revetment or turning to park.

Please excuse my adding my 2 cents to this discussion but the distinguished researchers and or webmaster have covered it all, in thorough loving detail, for you!

Warmest regards and best wishes,
Dan Katz
(I'd never even KNOWN there was such a B-17 Flying Fortress version as the "sharktail" until, at about age 13, living in North Hollywood, California, I saw "Air Force" on either KHJ(Channel 9, Los Angeles), KTTV(Channel 11, Los Angeles), or KTLA(Channel 5, Los Angeles) {all 3 independents, NOT NBC, CBS, or ABC!}(and they showed a LOT of movies: I first finally got to see "Dambusters" on KHJ's "Million Dollar Movie", then shown every night, Monday through Friday, at 8PM, and also Saturday and Sunday afternoons, during a given week[guess how many times this 16-year-old saw the movie made from a book he'd first read at age 9! What is that line Cary Grant tells Trevor Howard about finding the locations of those RAAN-hidden-all-over-the-island whiskey bottles of Grant's, when Trevor Howard (the RAAN commander who knows Grant all too well!) wants him to rescue another coast watcher in "Father Goose"? -"ALL OF THEM, FRANK!"} - just like every time "Air Force" or "Flying Fortress" is on and I find out about it far enough ahead in time!
I've always been a little slow: My dad, carrying me on his shoulders or holding me by the hand, showed me - at age 4 or 5 - what HE said was a Spitfire: bubble canopy, 5 blade propellor, clipped wingtips; I KNEW better, right up until, at age 13, William Green published "Famous Fighters of the Second World War," when I found out I'd seen a Spit XIV or later, with a Griffon engine!

[05564]

Your quite welcome to join in on any discussions we have here as I've said before that's why I enjoy this web-site so much!!! From what I've seen and heard , your 2 cents worth is worth so much more.

[pokryshkin]

That was VERY kind!

-as usual, I am both humbled and honored!

Gratefully,

"Dan" Katz

PS - this online "Posse comitatus" when assembled inb search of just about ANY information re the Boeing B-17 Fortress is clearly unbeatable!!!

-Talk about an information resource!!!!

[Second Air Force]

I finally got a photo of the tailwheel assembly to help make some sense of our descriptions.



The retraction actuator is the black motor and gearbox near the top of the photo with the retraction jackscrew and link to the right. The oleo portion of the strut is the chrome and grey cylinder. The port where we add nitrogen to charge the oleo is the little yellow cap at the top of the unit. The lower truss upper "A" frame can be seen where it attaches to the lower part of the oleo. The cable and pulley that's visible is the control for the tailwheel lock pin. This cable runs all the way to the cockpit tailwheel lock handle between the pilots.

Scott

[05564]

Thank you all very much for the great details to my question, especially this photo. I am assuming this is the down postition for the tailwheel. This clear's up all my confusion. Thanks again.

[Second Air Force]

Yep, down and locked.

The retraction jackscrew moves the grey link and oleo combination forward (to the right in this photo) to retract the assembly. We're going to be doing a gear swing/inspection on Chuckie in a couple of weeks and I will try to remember to shoot photos of the sequence of events.

Another little detail in my previous photo I didn't mention is the manual extension drive. Just behind the motor/gearbox is a green tube running aft. This is the driveshaft for the emergency manual system. There is a socket just in front of the tail gunner compartment that you insert a crank into and wind the gear down manually in case of loss of electrical power.

[Second Air Force]

I nearly forgot to post this excerpt from the Field Service Manual. It shows both retracted and extended better than my photos could:



Scott

[aerovin2]

Interesting stuff, here. Any idea why some B-17 operators have made their tail wheel retraction inoperative? It seems to be a fairly straightforward system.

[Second Air Force]

Scott,

The rigging of the up and down stop switches is a bit of a pain to accomplish, especially if a failure happens to occur on the road. Heck, there are a few photos of wartime Forts (The Swoose II comes to mind) with the tailwheel down in cruise also.

Another possibility for disabling the tailwheel retraction system would be when flying the airplane with reduced crew (not that anyone does that nowadays). Our procedure is to have a crewmember in the aft portion of the airplane to visually verify that the tail wheel is down-and-locked when prepping to land. If a failure occurred with reduced crew someone would have to go back there from the flight deck to crank the gear down.

Scott

[Second Air Force]

We did a gear retraction/extension check on Chuckie yesterday, so here are a couple of photos of the tailwheel retracted to go along with the extended image.

First, the down-and-locked configuration once again:


And retracted:


The actual linkage and jackscrew, first, gear extended:


Gear retracted--notice the threaded jackscrew just above the chrome portion of the strut and that more chrome is showing, reflecting the fact that no weight is on the gear.


Scott