Mike,

Be careful, one has heard that the resonance on the cub at
Booker was quite exciting, but this story may have been
elongated through time.

Mike Barnett (UK Hoffman dealer) would have been involved and
should be able to give you the definitive answers:

Skycraft Services Ltd.
Albany House
GB-Litlington,
Cambridgeshire SG8 0QE
Fon: 01763 852150
Fax: 01763 852593
www.skycraft.co.uk


The prop sits further forward as the 4 blader requires a spacer
between it and the crank hub.

For what its worth 4 blades can shift the noise into a more
annoying band for some people (I'm at CGC and we know a
thing or two about keeping peace with the neighbours)

GG


At 22:25 13 July 2012, Mike Millar wrote:

We have a PA18-180 towplane with 2 blade metal prop at East
Sussex
Gliding Club, UK and we have a noise problem with the local
residents.
We'd like to fit a 4 blade prop, but another club fitted one to a
PA18-180 and the pilots reported severe vibration - they
thought the
tail would fall off! So word has got around that it's impossible
to do.
That is obviously nonsense as Bert TW's club operate one and
there are
two in Switzerland operated by the Groupe des Pilots de
Montagne at
Aeroclub Geneve for a long time. These ones seem to have a
crankshaft
extension- the prop stands much further forward than the
standard 2
blade. Is that of significance? Any views on this? And will it
make it
quieter? We have a large muffler already.

MIke Millar




--
Mike Millar