Restored Mosquito Tail Shake, Common? Dangerous?

[over/out]

I recalled the time way back when, at Breck. TX. I was lucky enough to see Kermit Weeks Mosquito fly. I did notice that EVERY time his Mosquito landed, that when the tail touched down, I would see the WHOLE Tailsection SHAKE! After the second time, I made my way around the hanger to try and catch Kermit and let him know what I saw. I felt bad watching him step/climb down with a big grin on his face, only to see him concerned after I told him. Kermit was first class to let a warbird lookie-loo take his time I still think about the outcome of that and if it was corrected or just something common on the Mosquito. If this IS a serious problem, and might be look at in Jerry Yagen's Mosquito, I trust/hope my fellow wixers will pass this along to Jerry/MAM and Aspecs. In the meantime I will try to e-mail MAM & Aspecs.Thanks again, Anthony Neira P.S: Lets see more Hanger Mascots!

[peter]

Without seeing video of it it would be hard to diagnose.. modern day airliners wings shake alot when in turbulence and touchdown etc etc.

[over/out]

Thanks Peter, I hope wixers will come up with any views of Kermits Mosquito's last flights/landings. Thanks again, Anthony

[over/out]

Thanks TriangleP, It was the area just in front of the Horz. and Vert. If you were to take your hand out, fingers spread, and gave a RAPID "So-So" twist . I'll try the contact you gave. Thanks again, Anthony

[Dave Hadfield]

Are you talking about tailwheel shimmy?

That's an extremely common condition in any taildragger, usually caused by excessive play in the various components that support the tailwheel. It happens in all of them once too much wear takes place.

Everyone's probably encountered it on a shopping cart, by way of illustration.

I had to solve the issue on my Fairchild last winter -- see my thread in Vintage Aircraft.

Dave

[over/out]

Thanks Dave, If thats tailwheel shimmy, I'd say; "that's GREAT!" My main concern was watching a "Wooden" structure shake rapid like that. I know that Aluminum and Wood have thier strong and weak points. Thanks , A.

[AvroAvian]

All aircraft structures are flexible to some extent. Next time you are traveling in an airliner, especially if you are down the back with all the plebs, screaming kids, etc, watch the overhead bins sway, especially on landing.
One of my favorite party tricks if I was in the tail dock of a B767 and spotted some sucker trying to change a wing tip nav light, was to grab the fin tip and give it a good shake. The whole airframe would quiver and the wingtips would flap a good foot or so either way, causing much swearing and cursing from the intended victim.
If you really want to give yourself a good fright, go and do a good session of stalls in a Piper Tomahawk and look back over your shoulder...
The tail wheel shimmy theory on the Mosquito is plausible, but should be largely prevented by the anti shimmy channel tread tyre the Poms so love.

[Dave Hadfield]

I've never heard of a tire tread designed to stop t/w shimmy.

How does that work, AA? What's it look like?

Dave

[Ollie]

Dave, look at the tail wheel tyre on the Beaver.

[N3Njeff]

Also it should be noted that tail wheel shimmy is not as noticed on airplanes that operate on grass runways.. Don't watch the tail of most t tail airliners while taxing. You will never want to fly again.

[AvroAvian]

G'Day Dave,

Check this photo gratuitously flogged from the mossie.org site.....

[dxlyj]

G'Day Dave,

Check this photo gratuitously flogged from the mossie.org site.....

Rather interesting how similar the Mossie tailsection is to the Chipmunk (I guess that would be the other way round given the generations). The tailwheel yoke on the Chipmunk bolts to fittings on the rear bulkhead below the vertical fin spar. The tailwheel shock bolts to a fitting on the bottom of the horizontal stab which has the front spar bolted to the "ears" at about the 10:30 and 2:30 position on the rear bulkhead. Horizontal rear spar is supported by the brown tubes. And Super Chipmunks w/big rudders and "occasional" over redline flights have had issues with that whole area..
Dave (former Super Chipmunk owner)

[dxlyj]

G'Day Dave,

Check this photo gratuitously flogged from the mossie.org site.....

Rather interesting how similar the Mossie tailsection is to the Chipmunk (I guess that would be the other way round given the generations). The tailwheel yoke on the Chipmunk bolts to fittings on the rear bulkhead below the vertical fin spar. The tailwheel shock bolts to a fitting on the bottom of the horizontal stab which has the front spar bolted to the "ears" at about the 10:30 and 2:30 position on the rear bulkhead. Horizontal rear spar is supported by the brown tubes. And Super Chipmunks w/big rudders and "occasional" over redline flights have had issues with that whole area..
Dave (former Super Chipmunk owner)

Best picture I can find (look under/behind Luscombe left wing)..

[Dave Hadfield]

Oh, right, I have seen those tires, but I didn't equate them with a design-intent to counter shimmy.

Thanks,

Dave

[Baldeagle]

I had several rides in the Mosquito in 1990 when I was working for Kermit, that was the last year it flew, the last time at Oshkosh that summer. I don't ever remember any tailwheel shimmy, and there certainly weren't any issues with the fuselage or tail structure. He flew it a lot that year, to Sun 'N' Fun, to Canada, and to Oshkosh. Since the tailwheel is non steering or locking, always full swivel, I wouldn't think it would transfer much side load to the fuselage.



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