asking cuz i dont know. with same pitch why does it matter? is it more slip when up?
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2 aerate or not?????
- Thread starter Wrinkleface
- Start date
asking cuz i dont know. with same pitch why does it matter? is it more slip when up?
MOBILEMERCMAN
Founding Member / Competitor
The slip is a measure of efficiency on plane. When talking about coming on to plane slip isn't really applicable. Aerating does however allow the props to slip or more accurately stated ventilate. When the prop ventilates it allows the engine to rev up. Years ago many boats would ventilate on their own while coming on and at times had a negative effect but, now days with modern propellers and ultra high speed set ups a controlled ventilating is a must. Many thru the hub exhaust propellers have holes[ some with adjustable sizes ] to allow you to adjust the ventilation to improve a hole shot. Speed master drives are obviously different and aerating tubes are the way to get air in behind the leading edge of the prop to get it to ventilate.
For example a 525 and #6 boat like Amsoil can swing { not sure exactly } like 34 inch propellers and can go 130 some miles an hour. Say 3000 rpm's is 75 mph and 5300 is 130 { just guessing }. The bottom half of the propeller is doing all the work. The boat is running on plane and has little drag. Now to get it there with the available power, gear ratio, prop selection, entire bottom and drive dragging, entire prop biting, in a rpm range well under the power curve you need to slip the props to allow the engine to gain rpm's and get into its significant power range.
Wrinkleface
Founding Member
Teague said the rubber tubes helps cut down on vibration/harmonics compared 2 a solid tube! hey, if it's good enough 4 Bob!!
Wrinkleface
Founding Member
That bad boy sits on a hoist in Bay Harbor!! heard another 38 Fastech w/ Ilmors may B show'n up on Lake Char!!
Bobcat
Founding Member
I just got off of my pretend phone with Bob.....He doesn't even know who you are......name droppin fool!:leaving:
Wrinkleface
Founding Member
Punk!
Wrinkleface
Founding Member
Go'n down 2 Ilmor tomorrow 2 C my engines!!!:cheers2:
Perlmudder
New member
There were pics on the other site of a small cat, maybe a 26 nordic, or dcb that had a single number 6 running big power, and it had a sick carbon cover on the back of the drive that covered the aerator tube.
Ratickle
Founding Member / Super Moderator
If you take a look in post 16, that is the sister to Wrink's new boat. It will be hard to see the aerator tubes at all. From what Bob Teague was saying, surface drives have so much vibration that things loosen fall apart and crack pretty badly anyway. The tube sets up harmonics on top of that which make it worse. That's why nothing but rubber hose has worked so far in the long term.
Wrinkleface
Founding Member
engines were go'n on the dyno today! have not heard how things have turned out yet!!!
sy goldberg
Sponsor / Charter Member
HEY WRINK ! How do you aerate oars ?
rschap1
Active member
I am wondering why the harmonics and vibrations...
Props surely must be balanced.
Drive shafts need better concentricity and balance?
Should CV style joints be incorporated rather than universals?
Or is it just 1/2 the prop bing in the water and 1/2 above?
entering and exitting the water creating a "shock" at each event?
Just wondering if much investigation into this has taken place already?
In advance
THANKS
Props surely must be balanced.
Drive shafts need better concentricity and balance?
Should CV style joints be incorporated rather than universals?
Or is it just 1/2 the prop bing in the water and 1/2 above?
entering and exitting the water creating a "shock" at each event?
Just wondering if much investigation into this has taken place already?
In advance
THANKS
Wrinkleface
Founding Member
by shove'n up your wrinkly old butt!!!!!!:sifone:
Ratickle
Founding Member / Super Moderator
Wrinkleface
Founding Member
was gunna post up my starboard engine installed but cuz I'm puter stupid, I can't!!!! Rat said he would help but he never answers his phone!!!:smash:
