Rick Hi again! Nice to see you both at Henstridge
>At least until Paddy told me that, at 240 hours on my 912s, I am
> getting close to maybe having to spend the best part of 800 or 900 on a
> new sprag clutch and uprated starter sometime soon!
This situation was mentioned to make you and others aware that starting a
912S relies on efficient Sprag clutch and starter action and to be beware if
Engine 'fires back' fiercely and repeatedly that this might be the start of
stress on that Sprag clutch. The symptoms start with poor or delayed
starting which at first gives impression of poor cranking power from
Battery. In fact it's the Starter Sprag clutch slipping and not allowing
start to spin to firing speed. That condition only seems to take a few hours
to deteoriate and starts at about 200+ HOURS in some cases.
It may be possible to repair Sprag Clutch and I'm sure Paddy will respond in
his own right on this.
Whilst the Aircraft was unserviceable with this problem it seemed wisest to
replace clutch and probably a Rotax up rated Starter Motor isn't strictly
necessary. Paddy elected to fit the up rated Starter and the starting cycle
is awesome! It really does crank to the fastest start I've seen.
A friend with a Banbi (MCR001) experienced this problem first last year and
was the originator of the exhaustive investigation into the problem on his
912S by official Rotax UK Dealer taking a fair few weeks.
The 8.5:1 Compression of 912 and 914 are a reduced starter 'task' and should
be OK. 10:1 of 912S really exhibits it's compression 'kick' at shutdown or
aborted start cycle.
It will be interesting to see what trend develops as more and more 912S
Europa's gain hours. The Europa is a good 'benchmark' as everyone seems to
be always flying whenever they can! Let's hope Rotax are monitoring the
situation too.
All this is IMHO
Regards
Gerry
Europa 384 G-FIZY
Trigear with Rotax 912 and Arplast CS Prop.
Fuselage being Painted, Wings ready to paint, Flying surfaces painted
Airframe Wiring complete, Full Size Panel 60% done .
Includes Dynon EFIS, KMD 150, Icom A-200 and SL70 Transponder. AoA Fitted.
Activity on Panel, Designing Heater Unit, Shoulder Width Mod.
http://www.g-fizy.com
+44 7808 402404
gnholland@onetel.com
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