Hi, Mathys, I own an H-36 and also maintain one belonging to a friend. Between the two of us, we have had some interesting tailwheel issues. My bird was the scariest tailwheel aircraft I had flown ( about 800 hours in various Super Cubs, Cessna 180's and 185's and DH Beavers, etc.). If you breathed on the rudder pedals during takeoff or landing when the tailwheel was on the ground, it would threaten to leave the runway, and on two or three occasions I suffered PIO (pilot-induced oscillations) that shook my teeth. What I finally discovered was a logbook reference to a tailwheel fork repair. The fork was rewelded at that time with absolutely no trailing rake. We rebuilt it with 7 degrees aft rake and that demon was tamed. It now actually reminds me of a normally operating aircraft.
In the case of my friend's Dimona, most landings resulted in scary tailwheel shimmy--I thought it would take off the tailboom. He mitigated this at first by making wheel landings and holding the tail off as long as he could. On the couple times I experienced it, I braked as much and as soon as possible to get slowed down. We tried various tailwheel tire pressures and checked balance, etc.. It has been a while, so my recollection is a bit vague, but what I did discover by looking at the tailwheel fork while installed, the shoulder of the weldment where the vertical shaft enters the lower flanged spacer was not parallel with the face of that spacer. Upon disassembly we were able to discern some bending of the shaft at that point (the shoulder of the weldment and the tailwheel vertical shaft). We had a whiz of a machinist fabricate a new shaft and other parts of the tailwheel fork. I test flew it afterwards and it was a different airplane. Rudder cables were also replaced at a later date. Hope some of that is of help to you. Michael Stockhill Polson, Montana, USA On Wed, Sep 30, 2015 at 3:40 AM, Mathys Kuhn <[email protected]> wrote: > Hi Everybody > > I operate a mid 80’s model Hoffma Dimona in South Africa. Lately I started > experiencing a significant tailwheel shimmy at low speed after landing on a > tar runway. Has anybody ever experienced something similar? ANY ADVICE? > > Many Thanks > > > > *Mathys Kuhn* > > *Training Captain* > > T: 0825685614 > C: 0825685614 > F: 016 9330248 > e: [email protected] <[email protected]> > > > > *From:* [email protected] [mailto:[email protected]] *On > Behalf Of *Ian Williams > *Sent:* 23 September 2015 10:56 AM > *To:* [email protected] > *Subject:* Re: [DOG mailing list] Morning Glory Cloud Documentary > > > > Apparently only able to be viewed in Australia. > > Sent from my iPhone > > > On 23/09/2015, at 13:05, Rob Thompson <[email protected]> wrote: > > G'day All, > > For those of you who missed it, the Morning Glory Cloud Documentary is on > SBS "Catch Up" > > > http://www.sbs.com.au/ondemand/video/521484355510/secrets-of-a-strange-cloud > > cheers > > Rob > > Rob Thompson > 0429 493828 > > P Please consider the environment before printing this e-mail. > > ------------------------------ > > *Attention: * > Please note: This email and its content are subject to the disclaimer as > displayed at the following link http://www.comair.co.za/disclaimer.html. > Should you not have Web access, send an email to [email protected] > and a copy will be sent to you. > > ------------------------------ > >
