REFLECTOR:Nose Gear Shimmy

[Chuck Jensen]

The 75 kts is WITH the VGs!!  Big wings but the XL body and I don't imagine
that 540 hanging out back helps any.  I have no complaint with the handling
at low speeds.  Some comments have been made about the rudders not being too
effective at low speed but I'm certainly comfortable with the handling.
And, I'm more comfortable now that I did the Cleveland for Matco change out.

Then again....maybe its pilot shortcoming rather than design shortcoming.

I made a day trip to Cornelius Fort (kind of downtown Nashville).  While I
didn't mind the gaa-gaa staring by the FBO guy, I told him if he was going
to drool like that, he needed to get a towel or wash the whole darn plane.

Chuck




-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of Ronnie Brown
Sent: Tuesday, August 19, 2003 8:31 PM
To: reflector@tvbf.org
Subject: Re: REFLECTOR:Nose Gear Shimmy


Chuck,
On the 70 kts, have you tried the VG's?  Mine touches down at 70, stalls at
65.  But I have the big wings on the small fuselage. Handles good at low
speeds too.

See ya,
Ronnie

----- Original Message -----
From: "Chuck Jensen" <cjensen@dts9000.com>
To: <reflector@tvbf.org>
Sent: Tuesday, August 19, 2003 5:16 PM
Subject: RE: REFLECTOR:Nose Gear Shimmy


| John,
|
| Glad it made a difference.  You may want to progressively loosen the fork
| nut a little at a time.  I'm running 20 psig right now and a tap on the
| brake will turn the nose.  When I get a chance, I'm going to take again
| measure the force required to turn the nose. I can say for certain it is a
| "bunch less" than it was before but that's a just a qualitative
observation
| and means nothing.  Will post a good number when I have it.
|
| Congrats on the 70kn.  The only time I see 70kn is with all three planted.
|
| chuck
|
| -----Original Message-----
| From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On Behalf
Of
| John Dibble
| Sent: Tuesday, August 19, 2003 9:58 AM
| To: reflector@tvbf.org
| Subject: Re: REFLECTOR:Nose Gear Shimmy
|
|
| Well, Chuck, it works like a charm!  I reduced the nose pressure from 40
to
| 18 psig
| and no shimmy at high speeds.  Of course, as life goes, my test flight was
a
| perfect
| landing, touching down on the numbers at 70 kn, so I didn't give it the
acid
| test.
| However the following day after 6 hours in the air, it seemed that the
| Franklin was
| not running smoothly at any prop pitch setting (it was probably just that
I
| was
| fatigued, or does the engine get fatigued too?), so I had an unplanned,
and
| less-than-perfect landing at 80+kn at Punxsutawney (3000 ft, and, no, I
| didn't see the
| woodchuck).  Again, no shimmy at the maximum braking a Matco can offer.  I
| do get some
| shimmy at ~ 15 kn, so ultimately I will balance the wheel, but the higher
| speed is
| most important.  I haven't loosened the nut yet, but will do that soon for
| better
| steering.
| BTW, my flying club is having a fly-in breakfast on 9/1 (Labor Day).  We
| have a 3000
| ft grass strip in the middle of the Finger Lakes (NY).  Dundee - D48.  If
| anyone is
| interested I will provide more info.
|
| John
|
| Chuck Jensen wrote:
|
| > Well, in answer to John's query about the pressure I carry in the nose
| tire,
| > and contrary to Steve's experience, I found the softer-the-better, at
| least
| > to the point that the tire is "squishy" when pilot/copilot is loaded.
On
| my
| > first post, I was going to put in the pressures, then I thought that I
| might
| > just be showing/confirming my ignorance.
| >
| > At that risk, the initial pressure was 16.5#, which was a shock when I
| took
| > the reading because usually a smaller tire will have a higher pressure
and
| I
| > run my mains at 40#.  So, I pressured the nose to 35#, which resulted in
| the
| > shimmy.  When I reduced it back to 15.0#, the shimmy was gone.  I then
| > tightened the washers 1/3 turn to cinch them up a bit.  I haven't tried
| > increasing the air pressure since tightening the washers.  I'm going to
| > locate a good grass strip by my home base before I do that!
| >
| > Previously, I had the washers really tightened down and got tired of
| having
| > to "punch" the brakes to get the nose to break loose for steering.  I
| > disassembled the nose gear (it was pretty dry and grabby), cleaned,
buffed
| > and regreased everything.  When I put it back together, I tightened it
to
| be
| > somewhat less (though not measured) than the 15-20# recommended
break-away
| > force.  This worked great, easy to steer, until I increased the tire
| > pressure and made the tire hard.  My theory is the slightly softer tire
| may
| > incur greater friction and less bounce which reduces shimmy tendency,
| though
| > Scott's experience is directly contrary.
| >
| > A possible side benefit of the soft tire is less stress on the nose gear
| > during landing, particularly a hard one.  (I've never done one, you
| > understand, but I hear stories about others with lesser piloting
skills.)
| > The slight compression of the front tire would seem likely to reduce the
| > impact-shock if your nose drops on the runway instead of greasing it on
| like
| > I always do.
| >
| > Chuck
| > With ocean property in Arizona.
|
| _______________________________________________
| To change your email address, visit
| http://www.tvbf.org/mailman/listinfo/reflector
|
| Visit the gallery!  tvbf:jamaicangoose
| _______________________________________________
| To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector
|
| Visit the gallery!  tvbf:jamaicangoose




_______________________________________________
To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector

Visit the gallery!  tvbf:jamaicangoose