Michael what you wrote was very interesting. I will carefully look at our tailwheel when it returns from. North Australia.
Ian Mc Phee Australia On 2 Oct 2015 8:56 am, "Rob Thompson" <[email protected]> wrote: > The early H36 models had a straight un-damped tail wheel fork which, due > the wheels being forward of the centre of gravity and the heavy tail weight > can induce some quite nasty oscillations. > > As a result of this Hoffman later introduced a new tail wheel which has > shock absorbing rubbers. This reduces dramatically the oscillations but is > more prone to shimmy. > > If the tail wheel cables are too tight the steering becomes VERY > responsive to the slightest pedal movement. If the cables are too loose you > get shimmy. Takes a bit of experience to know when it is just right. Real > pain when you have to take the tank out each time to get it right! > > > > Rob Thompson > 0429 493828 > *Please note that my new email address is [email protected] > <[email protected]>* > > > ------------------------------ > From: [email protected] > To: [email protected] > Date: Thu, 1 Oct 2015 21:09:03 +0200 > Subject: Re: [DOG mailing list] Morning Glory Cloud Documentary > > Most interesting and helpful thanks Michael. My Dimona is also a bit of a > beast on the ground compared to other taildragger aircraft I have flown. I > will keep you pisted. Thanks for taking the time to write the detail. > Regards. > Thys > > > > Sent from my Samsung Galaxy smartphone. > > > -------- Original message -------- > From: Michael Stockhill <[email protected]> > Date: 01/10/2015 20:57 (GMT+02:00) > To: [email protected] > Subject: Re: [DOG mailing list] Morning Glory Cloud Documentary > > 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. > > > ------------------------------ > > > > > >
