Can a prop give bow lift???

[Infomaniac]

Yes Rake is The tip of the blade point aft. Hard to describe.
If you were to draw a line from the tip of the blade to the hub, the farther back it is angled, the more rake the prop has.

[Infomaniac]

Dave Rycroft worked that prop over for me. It was not even close to the same prop when he was finished with it. The blades were about half the original thickness and razor sharp on the leading edges. He left a ridge on the trailing edge. The water stops (slows) momentarily before it goes off the blade. Causes the prop to bite like crazy.
A B&M blown small block turned that 27 pitch prop 5,200 RPM with a 1.36 ratio Alpha SS.

[Havasu Hangin']

Infomaniac:
Yes Rake is The tip of the blade point aft. Hard to describe.
If you were to draw a line from the tip of the blade to the hub, the farther back it is angled, the more rake the prop has. Yeah...what he said.
Most 4 blades have smaller blades, so they do not extend past the end of the hub...
Infomaniac:
He left a ridge on the trailing edge."cupping" also creates lift...
[ January 15, 2003, 03:40 AM: Message edited by: Havasu Hangin' ]

[77charger]

Infomaniac:
A B&M blown small block turned that 27 pitch prop 5,200 RPM with a 1.36 ratio Alpha SS. out of curiousity how how long did the drive last?

[Trash]

I was waiting for someone to jump in with rake info. Blade shape and rake influence bow lift the most. RTJs, I've got a Mach Patriot you could try but unfortunately not enough pitch for your application unless you went with 1.36 gears. And that's not too economical....
You know, props are one of these half science/ half art things, and with all the boat tests, I'm wondering why there isn't a master database created to really pound out some emperical data. It would be a heck of a lot easier when it comes to prop selection time. It would need to consider more than just pitch and diameter too. Blade shape, rake, thickness, sweep, x-dimension, blade surface area etc. need to be included.

[rivercrazy]

Keep this info coming!

[gnarley]

It would be nice to see everyone post REAL MPH, HP, RPM, ratios, hull type, weight, Prop size, type prop, work done to them by whom, & what they did to the actual ride. This could start some collective type input for a database to share in helping everyone with prop selections based on real world testing!
Maybe Hot Boat would compile the list for all forum members who would share the info & make it available for us to see??? It would make life a bit easier sharing real info knowing what to expect from someone else’s hard earned knowledge.

[Infomaniac]

We'll have some good data in a month or 2. I am building a 10-71 blown 540 for "Well Done". It will go in his 23' Wyatt tunnel. Built here in Oklahoma. Going to see if it is possible to get this thing to 120.

[Infomaniac]

77charger:
Infomaniac:
A B&M blown small block turned that 27 pitch prop 5,200 RPM with a 1.36 ratio Alpha SS. out of curiousity how how long did the drive last? I ran it for 8 years and as far as I know it is still going. Not the same power inm front of it. An Alpha SS is fairly stout. No wide open starts helps.

[Hermosa]

gnarley:
It would be nice to see everyone post REAL MPH, HP, RPM, ratios, hull type, weight, Prop size, type prop, work done to them by whom, & what they did to the actual ride. This could start some collective type input for a database to share in helping everyone with prop selections based on real world testing!
Maybe Hot Boat would compile the list for all forum members who would share the info & make it available for us to see??? It would make life a bit easier sharing real info knowing what to expect from someone else’s hard earned knowledge. Stingray boats did something like that, they tested each boat, motor package and prop with real world test results, so you can get a good idea of how your boat will preform before you order the setup. I'm sure it took them some time and money for all tht extensive testing, I would love to see other manufacturers do that, especially the custom boat companies. You pay a lot for the boat, give us some good data and testing also. It wouldn't be that hard to call all their new boat owners a year after the get their boat and see what props have been working for them and in what application. A little R&D would be nice...