The Airmaster hub design is now over six years old and is currently its third
generation. The highest number of hours flown by an Airmaster hub to date is
620 on a 914 powered Pelican with no issues observed to date. The Europa
Aircraft demonstrators have also been flying with Airmaster hubs for two years
and have ammased several hundred hours of operation on each aircraft.
The blade retention system and design of the Airmaster hub is very different to
that used by NSI and was designed from the outset to handle engines up to 120hp.
Tony
Quoting jean-philippe_neel@mail.schneider.fr:
> Bonjour Nigel
> Do you know that Airmaster prop uses also Wrap Drive blades?Is there
> any
> risk to find a similar problem ?
> It's probably difficult to get a good answer as the total hour flying
> of
> Airmaster prop is very low at the moment
>
> JPN N 273 F-PSLH
>
>
>
>
>
> Nigel Charles <72016.3721@compuserve.com>@europaclub.org.uk le
> 13/04/2002
> 10:41:01
>
> Veuillez rpondre forum@europaclub.org.uk
>
> Envoy par : forum-owner@europaclub.org.uk
>
>
> Pour : unknown <forum@europaclub.org.uk>
> cc :
> Objet : NSI CAP140 prop/Rotax 912S
>
>
> All UK operators of the NSI CAP140 prop/Rotax 912S combination should
> already be aware that there is a potential problem with this
> prop/engine
> combination. One UK operator has had a crack appear at the root of one
> of
> the blades after 250hrs operation. The prop had already accumulated
> 500hrs
> with a Rotax 912 without problems. A possible cause for this is
> described
> below and other prop operators may like to take note as the loads on
> any
> prop are increased by the 912S over the 912. NSI now provide blade
> cuffs
> with thicker aluminium to compensate. These stronger cuffs have been
> standard since 1998 but are only likely to be essential in conjunction
> with
> the 912S. As a precaution in the UK the PFA strongly recommend that no
> Europa with this prop/engine combination flies more than 25hrs until
> the
> upgraded cuffs are fitted.
>
> The higher compression ratio of the 912S is placing greater loads on
> the
> blades during shutdown and on kickback on an unsuccessful start attempt.
> I
> understand that Rotax is considering offering a more powerful starter
> motor
> to reduce the chances of kickback. The PFA is recommending that, on a
> cold
> start, the choke is only pulled out when full cranking speed is
> achieved. I
> would also suggest that it makes things easier for the starter if the
> prop
> is positioned just after a compression point during the walkround
> before
> start. The motor then has more chance to up to cranking speed before
> having
> to overcome the high compression.
>
> I am one of those affected by this and, as my aircraft is approaching
> the
> 25hr limit, I will shortly be grounded. My prop has had no problems and
> rather than going to the expense ($650 plus international shipping
> costs)
> to upgrade the cuffs for 912S use I am considering changing to the
> Airmaster. This is not cheap (current UK price 2840 +VAT). As a result
> my
> very low hours prop could be available for use with a 912 (or Jabiru,
> Subaru etc) to get a little more performance. The NSI is electric
> variable
> pitch (but without constant speeding) enabling max rpm on take-off and
> more
> economic and quieter cruising. I am looking to get 1200 for my prop
> which
> is less than half its original price so this may be an economic way for
> someone to upgrade from a standard ground adjustable prop.
>
> As it will take 30 days for Airmaster to make and deliver the new prop
> to
> me I am looking for help in keeping my Europa flying in the meantime.
> To
> this end, is there anyone in the UK who has a fixed pitch prop they
> can
> lend me until my new prop is ready?
>
> Nigel Charles
>
> Tel 01380 860620
>
>
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