Back Up Next

Snubber Cable
and
Crosswind landings

Disclaimer: We have no professional or expert qualifications of any kind.
It's fully up to you to check any information you find here with
standard aviation industry sources such as aircraft maintenance
manuals, flying instruction books and, above all, FAA regulations!

By Ed Burkhead

I'm inclined to go with the designer.  Fred Weick thought the snubber cable should not be used. 

With NO snubber cable:

The mains touch first.  As the main gear shock absorbers compress, the nose gear touches no matter whether you hold the nose off moderately or radically.

When the nose wheel does touch, the nose wheel TURNS instantly to line up with the direction of motion (as long as the pilot does not inhibit this turn by a firm grip on the yoke (or rudder pedals).  This means there's no side load on the nose gear other than an instant surge that has been shown, though bunches of Ercoupe crosswind landings, to not damage the gear.

As soon as the nose wheel finishes its instant turn, nose wheel steering becomes available.  The weight of the aircraft on the mains will cause the aircraft to pitch downward, dumping lift and bringing full (or nearly full) weight onto the nose gear, thus insuring full nose wheel steering.

With a snubber cable

All these same things happen though, if you manage nearly zero the vertical speed at touchdown, the aircraft might do much of its turn to line up with the direction of travel over the ground BEFORE the nose wheel touches.

Finally, WITH NO SNUBBER CABLE, the nose gear can extend fully.  In flight, with the nose gear fairing reinstalled, the aircraft gains very close to one (1) mph as carefully measured, according to Fred Weick. 

Upon landing, the nose gear has its full shock absorbing ability with increased ability to resist damage to the nose gear and engine mount.

Summary:

If you can reliably land with near zero vertical speed, then having a snubber cable has an advantage in lowering side stress on the nose gear and, due to your skill, you have no risk from the degraded shock absorber.

If your landing skill is not in the expert range, your nose gear may benefit more from the additional shock absorber effectiveness than from the fraction of a second to couple seconds delay in nose gear touchdown.

If you want the extra one mile per hour, remove the snubber cable and ensure the nose gear fairing is properly installed.

JMHO

 ____________________________________________

 

From a maintenance point of view

by Hartmut Beil

Fairing or not, I found the snubber cable something to be worried about.
 
It was introduced with the Mooney M1 to give the aircraft some trainer qualities.
 
Mooney found the perfect landing and immediate steering qualities of an Ercoupe not adequate for a trainer aircraft.  Wanted to make it a bit harder. Also, the M1 has a bigger rudder that allows to steer the aircraft with the rudders down the runway. That is something most Ercoupes don't have. With decreasing speeds , rudder authority diminishes and the steerable nose wheel comes in handy.
 
Introduced in the sixties, at times where everyone was embracing anything new as something better and even better, the snubber cable came out as the latest greatest thing. A retrofit seemed the best thing to do.
 
Remember, the cable does not secure parts of the noses gear, even if it looks that way, it just merely reduces the length of the exposed nose gear inner strut. And with that it reduces the dampening qualities of the nose gear.
 
This can lead to some shocking results. As I collected here:
http://www.ercoupe.info/?n=Main.BrokenTaxiSpring
 
With a snubber cable you are removing the dampening qualities of the nose strut. Upon landing all of the forces are only held up by the taxi spring. That spring is not designed to withstand landings and will break. Also the shocks have to be absorbed somewhere. And the next thing that will break is the engine mount. It might develop  cracks or just bend.
 
 
But why not on the Mooney M1 you might ask?  There too I'll answer. Mooney probably did not redesign the strut, Mooney added the snubber cable to make the plane more behave like a training aircraft.
 
They probably calculated that it is cheap and easy enough to either exchange or rebuild the strut when it starts failing, but I even think that nobody really understood the consequences of their design change.
 
Now half the Ercoupe fleet has this dangerous strap on their nose gears . Nobody dares to remove them and everyone who has one puts his plane in danger.  It is like taking the shocks out in the front of your car and substitute them with metal rods.
 
Some say "mine is still moving an inch or so up ad down".  I say that is not enough to be even felt.  The strut needs the whole length of movement to develop its dampening action. The struts on our Ercoupes are not like car shocks.  Car shocks are basically always on taxi mode and are design to reduce oscillations of the car body. For that an inch or so movement is plenty.
 
The Ercoupe has struts that are designed for landing and taxiing.  Landing is one big hit. To absorb that, the struts need to hang down as designed. After the landing hit, the plane sinks onto the struts taxi positions. The snubber cable keeps the nose strut always in the taxi position.
 
If you like that, why not keep the main gears in that position too?