T-Hydro 135.9mph pass at Legg Lake SAW's Jan 25th

[martin]

The ic motors like the Picco 60 is certainly running well below 30000rpm, but its the amount of pitch that's being used + the blades are very narrow at the root. Hence having to use high tensile steels now, the propshop stainless props are very old design props & will simply bend the blades back. The result then is the rear of the boat starts hopping which then in turn snaps the blades or worst still destroys the boat.

[RaceMechaniX]

Thanks Martin,

For me I cannot spend the time hand shaping propellers, more importantly I am not skilled at it. I am much more skilled at learning what shapes work from running existing props and designing them to have them made my modern techniques. One such way is CNC'ing from barstock, the other is printing a 3D model in polymer and using this as a master to cast off of.

I would still like to browse some tether sites if you could provide them for ideas.

BR,

TG

[martin]

Anyone involved with tethered boats has always had to make everything themselves as their is nothing commercially available. You can go to www.onthewire.co.uk but theirs not much info on modern boats apart from a few pics & records etc, a lot of the site is older boats like vintage hydros

[martin]

http://youtu.be/jirDGL6vL1A This is a 10cc A3 class boat with Picco 60 tether car motor running around 138mph (no nitro allowed 80% methanol / 20% castor ), note the duration of the run time compared to SAW runs.

[RaceMechaniX]

Thanks for posting Martin,

I have visited on the wire, but like you said it's mostly vintage material. Still interesting to look through.

TG

[Kris Flynn]

Out of interest, why not CoCr? Have you spoken to Peter at CoCr racing in Aus? He does great work and isnvery knowledgeable. I have not heard of anyone having issues, having said that not many running them over 50k rpm if any.

[RaceMechaniX]

Kris,

Nothing against CoCr as a material. It has more to do with keeping the prop secrets in a tight knit group. Several friends with much better prop knowledge than me have offered to help out in this area so my preference is to work with them.

TG

[TristanJones]

Awesome, awesome run. Congrats!!
Awesome thread!! Thanks for the read.

[Kris Flynn]

I get you now mate, I fully understand where you are coming from!