Prop failure at high speed

[grsboats]

Well It happens when you try to push hard your boat.After lot of good tests I lost one blade in a fast pass,fortunetely far away from the shore with minor issues to the boat,only have to put a new flexshaft.All props hardened and holding well those mega pressures but this one NOT.Enjoy Gill

http://youtu.be/mxYFCLUbWOI

[Alexgar]

Gil like that Mercedes SUV in the background. Cool that that was is what was the rpm ? Last time I lost a prop blade at much lower rpm it unbalanced my cable and made spaghetti out of my flex. What speeds were you running there?

[T.S.Davis]

Beautiful boats Gil.

[Alexgar]

Fyi tberes not a car or.boat I.own that pumps less than 35000 rpms. Go for broke or lose that my moto

[Fella1340]

Nice boat Gil, you guys look like running real fast out there. I need to learn a lot about props, really interested in the high precision balancing required and how the props are hardened. Is us anything like tool steels where you harden to a desired (is it measured in Rockwell?) hardness and then temper the material back a bit so it's not brittle from hardening? Sorry, those questions leave a lot to answer to. I haven't seen or heard of much of it being done, which means little but if you could share a little it would be well appreciated. How fast are you guys going?!

[grsboats]

Thanks guys for the nice words.Alexgar this a Defender 110 Land Rover customized by myself for a different looking.Prop was precisely profiled,sharpened,balanced and hardened but at those rpm's it happens to break after hammering so hard water....I'm sending this one and other props that also failed in this area for a close inspection to figured out what can be done .This boat is equipped with a Tp 4060(2040kv) plus Castle 240 and datalogging is nice:watts 4982,temp 46C,amp 243,2A,rpm 47753.gps'd with Garmin at 152km awesome for a heatrace boat that obviusly will not run that fast at the course but it is always nice to see how fast a model can go.Fella take a look at this link about hardening props..btw this is what I do to my wheels:

http://www.modelgasboats.com/resources/propeller-related/heat-treating/

Cheers] Gill

[Fella1340]

Cool Gil, thanks for sharing your setup and data logging numbers, that's one fast boat! Racing with other boars at those kind of speeds must get the heart rate going. Little room for error I would imagine! Good luck with the boat. Can you post a picture of the inside? Can't imagine where e everything goes, if it's a secret layout I understand

[grsboats]

Fella you're welcome and yes it's a heart beating hobby.lol.Actually heat race speeds rarely are up to high 70's in the straights but even slower there's no room for misdriving.No secrets here so take a look to my page and enjoy!
link:http://www.grsboats.com.br/?p=6707 saw version
link: heat race:http://www.grsboats.com.br/?p=7703
Thanks for reading
Gill

[grsboats]

Take a look to the roostertail...the black hole behind the boat is the right moment I lost the blade!

[urbs00007]

Well It happens when you try to push hard your boat.After lot of good tests I lost one blade in a fast pass,fortunetely far away from the shore with minor issues to the boat,only have to put a new flexshaft.All props hardened and holding well those mega pressures but this one NOT.Enjoy Gill

http://youtu.be/mxYFCLUbWOI

hi gil, could you post picture of how you mount video camera to video the boats? I use headband from welding helmet and mount off to the side.

[grsboats]

This what I use:http://www.dx.com/p/convenient-outdo...6#.U3ywv2cU-Uk
Cheers
Gill

[HydroMike]

Nice riggers there gill

[grsboats]

Thanks HydroMIke.We are working in a twin rigger so soon more vídeos.Gill

[twissted]

I just had a new prop break this last sunday. I just ordered some 1448/2 cnc props to try.

[grsboats]

Twissted I have tried few Alu CNC props and they don't survive too much in my riggers.Thanks Gill