REFLECTOR: towbar

[Bob Jackson (Jax Tech)]

I think having the CG forward of the pivot point will tend to make the nose
wheel unstable and want to flip around 180 -- didn't you say that backwards,
Brian?  Having it aft of the CG would make it more stable and less likely to
shimmy, correct?  What am I missing?

 

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Brian Michalk
Sent: Saturday, November 06, 2010 11:51 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: towbar

 

Nice design, but normally, you want CG as far forward of the pivot as
possible, not aft.

Also, there was an analysis here ... I think by Ulmann, who concluded that
our shimmy problems are not caused by the CG/pivot arrangement.

On 11/05/2010 11:46 PM, Bob Jackson wrote: 

Dave,

 

Our gear is retractable, so I'm not sure exactly how you might apply what we
did.  However, I can tell you that although many Velocity's don't make any
provision for it, we have found that adding a standard tow bar male 'tang'
arrangement to our nose gear leg has been an invaluable feature.  

 

Moving the plane around in a crowded hangar at home, or when you're
traveling, it has been 'priceless' for us to be able to use a standard small
Cessna type 'manually' controlled tow bar, or one of the big orange ones
(common at most FBOs) to move our plane around.

 

It might be more essential because our Velocity is so heavy, but when we
have a full load of fuel (93 gals), it is very difficult to move our plane
around -- either trying to push up small inclines, or for tight maneuvering
because with full fuel it is essentially impossible to pick up our nose to
make tight turns (unless you enjoy hernias!).

 

My aircraft partner designed (with some ME help) and had fabricated the tow
bar adapter shown below, as it is attached to the top of our nose gear fork.
This is the front view.  It is also important (as I'm sure you would
appreciate) that the extra weight of the 'tangs' is on the back side of the
fork -- for anti-shimmy reasons.