Hi Justin,
So sorry to hear your unhappy news, but if it is of any consolation, there
are many of us that have had similar misfortunes.
I would just like to add one thing to all the other advice and that is to
have an aft C of G. When I changed to a VP prop I placed 4.5 lbs of lead in
the tail. This brought the C of G to the aft limit of the envelope, when I
was alone in the aircraft, with a full tank of fuel and 80 lbs in the
luggage bay, which is the worst configuration of loading. This maximises
the load on the tail wheel and therefore reduces the tendency to nose over
and ground loop in a strong cross wind. It also reduces drag in the cruise,
because the tail plane is not having to work so hard. The only disadvantage
is that it is more difficult to trim in pitch as it tends to wander between
nose up and nose down if there is any turbulence about.
Best wishes,
William
----- Original Message -----
From: "Justin Kennedy" <Justin@systemwise.co.uk>
Subject: Europa-List: Europa G-ZTED Prop Strike
> <Justin@systemwise.co.uk>
>
>
> Prop Strike!
>
>
> Our aircraft G-ZTED is a Europa Classic Monowheel Rotax 912S with an
> Airmaster A332 Propeller.
>
> Our lovely Europa, our pride and joy, was only 17 hours old when we went
> to our first fly-in. I was taxiing on rough grass and slightly out of
> wind, the tail lifted and, o woe and thrice woe, the propeller dug into
> the soft turf breaking three blades off and damaging the variable pitch
> mechanism of the prop.
>
> Lots of thought and soul searching not to mention upset later we have come
> up with a set of rules for taxiing our Classic Monowheel which will
> hopefully avoid this happening again. The Rules are on the back door of
> our trailer stuck to the broken blades to remind us. I would like to have
> seen these and thought about them before it happened to me. I offer the
> story here in spite of the embarrassment, knowing that if it saves just
> one propeller that it is worthwhile.
>
>
> The elevator of the Europa is powerful, it's brakes are good and the
> Centre of Gravity is not that far behind the mainwheel. Coupled with this
> we have the Rotax 912S with an Airmaster A332 constant speed prop which,
> when set to fine, can produce a thrust of over 500 lbs on the ground. Each
> one of these things can lead to the tail becoming light and in a number of
> circumstances they can add together to cause a certain propeller strike.
> All these forces act in the same way conspiring to wreck your propeller,
> your day, your self esteem and your bank balance.
>
> So, to counter this, we have devised a set of Rules which I am going to
> adhere to.
>
> It should be food for thought for new Monowheel owners.
>
>
> Rule 1: DO NOT Use more than 3000 rpm to taxi.
>
> This puts a limit on the amount of thrust which tends to tip the nose
> forward. If the ground is so rough that more than 3000 rpm is required
> then you should not be there. Shut Down and pull her out. It is a lot
> cheaper than a propeller.
>
>
> Rule 2: DO NOT Taxi with Power against the Brakes
>
> This is much the same as number one. Taxiing against the brakes produces a
> tendency to tip the nose forward. I can think of no occasion when it is a
> sensible thing to do so it is now off limits.
>
> Rule 3: ALWAYS Do the run up check directly into wind
>
> This may seem obvious but given the situation where you were say 40
> degrees out of wind in a blustery 25kt wind. The power goes on for the run
> up against the brakes. This makes the tail lighter but you pull the stick
> right back. Due to the strong side wind the prop wash is not operating on
> the upwind side of the elevator and the aircraft is very tail light. The
> blustery wind gusts under the windward elevator and the equation is
> suddenly not in your favour. Obey rule three and this won't happen.
>
>
> Rule 4: ALWAYS Centralise Control Stick when taxiing out of wind
>
> Again this is obvious. The all flying elevator is so powerful that if
> pulled back it is enough to lift the tail all on it's own without any of
> the other factors helping it. Due to the taxiing attitude of the monowheel
> the ailerons are best centralised out of wind.
>
> Centralised controls make the Europa Monowheel quite stable when taxiing
> downwind.
>
>
> Rule 5: NEVER Taxi on Rough Grass
>
> This is a bit extreme but after our experience we are going to stick to
> this. The Europa Monwheel's big wheel makes landing on rough fields
> possible but taxiing on rough grass is risky. If 3000 rpm won't take you
> then Shut Down and get out and pull it out. Believe me it is cheaper to do
> that.
>
>
> Rule 6: NEVER Use Power to overcome obstacles. When you get stuck.
> SHUT ENGINE DOWN and get out and pull it out.
>
> OK this is Rule five again but it is the most dodgy thing to do. Directly
> into wind it may be possible to get away with more thrust but our
> Airmaster Propeller is a wonderful piece of kit and makes our aeroplane
> very good cruising machine. It can pull the nose over with very little
> help. Why risk it.
>
>
> The above instructions are now incorporated into our Pilot Notes.
>
> We are just getting to know what a fantastic aeroplane we have made.
>
> See you around.
>
>
> Justin Kennedy
>
> G-ZTED
>
>
> --
>
>
|