[hpv-boats] Rigid Shaft

[v garza]

If that 71 degrees is off the horizontal, seems like a long, untethered flex 
shaft could be used to correct, since it always remain at the optimum. I 
don't know the configuration of your boat, so you may have already 
considered and rejected due to your arrangement. When Greg K set his 24 hour 
distance record with an untethered shaft, it only amounted to about a 2% 
improvement compared to a skeg and inclined rigid shaft, but I don't know if 
the angle of inclination was ever as great as 71 degrees...

Hope this helps.

Vic
----- Original Message ----- 
From: "Ian Cassell" <iancassell at optusnet.com.au>
To: "Human Powered Vehicles --Boats" <hpv-boats at bikelist.org>
Sent: Monday, January 17, 2011 4:16 AM
Subject: [hpv-boats] Rigid Shaft


> Rick
>       When I first used the 16mm rigid shaft it vibrated
> a bit but its something I don't notice now. Inside the 16mm
> aluminium tube I have a wooden rod glued into place.
> I kept coating the rod with an expanding glue as I
> pushed it into the tube. This makes the shaft more rigid
> as well as a bit stiffer torsionally.
>        With the 16mm shaft angle I am thinking of making
> another prop with a different pitch. For example the prop
> at one point is angled at 55 deg but with the 16 deg shaft
> angle the actual angle is 71 deg. The prop is only at
> optimum in the horizontal and looses in the vertical. If
> I made a 4 blade prop with a different pitch to suit the
> shaft angle there would be more prop at optimum thrust.
> I might be way out here but it would be interesting to see
> how such a prop would work.
>        Where I often go at the rowing course and the river
> weed is not a problem, just bump into a jellyfish now
> and then.
>         Had a lot of expenses of late so the GPS has
> been put on the backburner. Have to do timed runs at
> the rowing course.
>
> Ian
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