Is this new E75 prop gap right?

[Parsonsjb88]

I bought a new 155 e75 -5mm prop from impros pitched to 7/12 and I am a bit confused as to the huge gap to the stator veins. The trailing edge is bent up at a huge angle which leaves probably a 12mm tall triangular gap between the blades and the stator. This is the first 155 prop I’ve purchased but it seems extremely poorly designed, especially compared to the clearances I see on typical 144mm hookers. Just looking for some insight is this normal for these 155 props or if something is wrong.

 

[TheBuzzard]

Leading edge bent way down and trailing edge bent way up , should mean its a tiny prop. Bent the other way is a huge prop with huge power requirements to turn it. 155mm pump uses about a 5/10 prop if it's for freestyle and smaller motor. Surf prop is a bit bigger but not much. Prop sellers are usually full of crap on pitch and sometimes lie about even pitching it to what you ordered. Edges closer to the veins means less slippage so makes the prop seem even bigger

 

[kevbo]

The whole idea of having the impellers trailing edge right against the stator was something IMPROS was selling years ago. The impeller MFG may only cast one or two different pitches of a particular product. The blades are bent to get the correct load. My hardest pulling 144 Solas looks like the one pictured.

 

[Flash-FX]

The "business card" or really close space between the trailing edge of the impeller and the stator veins worked great in the 440 style and stock FX-1 122mm pumps. That significantly reduced cavitation. especially in the surf behind a bigger motor. The gap in that 155mm might actually help to get the motor up to speed from the very bottom end. Especially if it's slightly over propped for the motor setup/size/tune.

 

[Parsonsjb88]

All good knowledge. Thanks.

Problem I’m having is it feels underpropped right now paired to my ET967. I went to adjust the trailing edge to 14 deg from the current 12, but with the way impros bent the blades upwards, the radius now increases when increasing the pitch and prop won’t fit. Apprehensive to grind the radius down on a brand new $400 prop


Sent from my iPhone using Tapatalk

 

[fastgtfairlane]

Prop sellers are usually full of crap on pitch and sometimes lie about even pitching it to what you ordered. Edges closer to the veins means less slippage so makes the prop seem even bigger

I have to agree. I ordered a 7/14 skat impeller for a 148 pump and after checking it with a torrent pitch gauge, it was off almost 2 degrees. So I'm curious how someone like impros measures the pitch on the impeller and where on the blade its measured. I figured they measured a different method than I did and that's how it came up 2 degrees different.

 

[TheBuzzard]

All good knowledge. Thanks.

Problem I’m having is it feels underpropped right now paired to my ET967. I went to adjust the trailing edge to 14 deg from the current 12, but with the way impros bent the blades upwards, the radius now increases when increasing the pitch and prop won’t fit. Apprehensive to grind the radius down on a brand new $400 prop


Sent from my iPhone using Tapatalk

If the nozzle is bored, change it to an unbored stock size one and if it has a stubby pump cone in there, change that to a long one. That'll make the prop seem bigger. The previous owner of my dasa 1000 freak bored the nozzle. When I put a stock nozzle on there, it made a huge difference

 

[Christian_83]

All good knowledge. Thanks.

Problem I’m having is it feels underpropped right now paired to my ET967. I went to adjust the trailing edge to 14 deg from the current 12, but with the way impros bent the blades upwards, the radius now increases when increasing the pitch and prop won’t fit. Apprehensive to grind the radius down on a brand new $400 prop


Sent from my iPhone using Tapatalk

Dont stress it. Bend it up (pitch up) and when then blades increase diameter, you can file/sand the blades to get the correct blade to wearring clearance.
Thats how i pitch my impellers, works very well

 

[Parsonsjb88]

Dont stress it. Bend it up (pitch up) and when then blades increase diameter, you can file/sand the blades to get the correct blade to wearring clearance.
Thats how i pitch my impellers, works very well

Agreed and coincidentally just did this last night. Ready to reassemble and test this weekend.

Also I would love to try a stock nozzle but I don’t have access to one and don’t really want to buy one. I believe I have a long cone though so I’ll take that out with me when I test the changes to the prop pitch soon.


Sent from my iPhone using Tapatalk