Karl and all,
IMHO the steel springs or the bungee on a trike nose gear are all meant
to purely accommodate severe shock on a bad landing which otherwise
would have a drastic effect on the nose leg, that is it permits the leg
to move upon receiving a sudden load which otherwise would take it in to
yield stress regions. The so called suspension of the nose wheel depends
entirely on the leg itself flexing. ( That's not to say I like the idea
so don't shoot the messenger!) In any case too much suspension you need
a new propeller ! I had a bad experience with the bungee ( well one or
two really !) when the bump stop had passed through the lays of reeved
bungee cutting through the bungee letting the nose leg extend to the
wire safety strap. Francis Donaldson gave me dispensation to put the
bump stop the other way up fixed to the upper tube and bumping on the
leg between the lays of bungee. This worked OK and so it didn't need to
pass between any bungee reeving. ( I also managed on a wheel barrow
landing to bend the leg downwards prompting Neville Eyre to quip "had I
landed wrong way up ?" Andy Draper was present and so realized there and
then that due to the geometry of the castering pivot any load from
forward of the wheel centre line actually will result in the leg being
bent downwards!
Since my nose wheel departed on a "greaser" landing event (now with the
leg replaced and springs employed) I have an extended pivot spindle with
two roll pins as keepers in place of the single one all has been well.
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Karl Heindl
Sent: 15 April 2009 02:43
Subject: RE: Europa-List: Mod 70
My own experience confirms this. A spring suspension on the mono would
cause some very interesting landings. It's bad enough on a trike. Very
similar to : removing the shock absorbers from the front suspension of
your car, and driving it at 80 90 km/h along a bumpy grass field.
Karl
> Date: Wed, 15 Apr 2009 00:51:44 +0100
> From: grahamsingleton@btinternet.com
> To: europa-list@matronics.com
> Subject: Re: Europa-List: Mod 70
>
<grahamsingleton@btinternet.com>
>
> Robert Borger wrote:
> > Raimo,
> >
> > My understanding from discussions with Nev is that the spring
reaction
> > of a metal spring is incorrect for this application.
> >
> > Bob B
> The important point is that rubber has a damping effect but steel does
> not. This is why rubber, (elastic) is better than steel (springs) for
> undercarriages.
> Think about it, a spring goes "boingyoingoing" but a rubber band goes
> "thwack"
> Graham
&g===========
>
>
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