Gear,Prop help please!!
#1
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Joined: Oct 2005
Posts: 545
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From: Nashville,TN
I just recenty purchased a 24 ft HTM. It has 1.36 gears on a bravo 1 with a 19 pitch prop turning only 4100 rpm at 55 mph..motor is a 7.4 mpI 310hp. i was wondering about going to 1.50 and uping my prop any info would be greatly apperciated!!!
#2
The gear change would help your overall performance from low end to mid range throttle response and not compromise top speed.
Expect to up the pitch on your propeller by 2"s.
Expect to up the pitch on your propeller by 2"s.
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Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
#5
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Registered
Joined: Oct 2005
Posts: 545
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From: Nashville,TN
Hello again. i tested a bravo 1 with 1.5 and several different props. it is possible that tach is off but im using gps speedo. I still have a few more to test, so this is mainly an fyi for the experts. we tried a 21p 3 blade and a 23p 4 blade. 21=4900 rpm at 52mph. 23=4200rpm at 56 mph. will try a 22p 3 blade. THANKS!!!!!!
#6
here is a link to a prop calculator, you can input different props and rpms and see the differnece, I still think you need to check your tach,
http://www.rbbi.com/folders/prop/propcalc.htm
http://www.rbbi.com/folders/prop/propcalc.htm
#7
23 4 blade slip numbers come to 8.17%. Very good depending on the casting used.
__________________
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
#10
1.36 gears can be easier on the drive life. However, if the HP is within the drives capacity, 1.5:1 gears can produce better throttle response and still maintain longevity.
bajabob, your slip is under 8%. That's great for any boat including a Baja!
bajabob, your slip is under 8%. That's great for any boat including a Baja!
__________________
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]




