Surface Drive Prop Rule
 

Is there any rule for a surface drive in terms of 200 rpm per pitch change. I am running 16 1/2 X 24 4 blades. At 0 trim or neutral trim i am @5700. The motors stop making power at 4900. I am going to try 30 pitch 3 blades. i have talked to a couple people on this and everyone said u gotta try them to figure it out. BTW 311 Formula KAAMA drive 1.54 trans 1.1 drive with 409 HP

OK prop tested sunday.

17x30 3 blade 63 @5200 anybody have any suggestions?

The set up you got has 24% slip.
Something is wrong ?!

I think 3 blades are not good for ya. $ blades in the right size is what you need.

If your engines turn 5200 RPM ,with a 26 pitch prop and a 1:154 gear ratio the boat should run 73.2 MPH on GPS.

That would be the ideal slip # .
My guess is 18 X 26 4 blades ??????? Maybe 27's ???????

Thanks maybe that is something to look at. also i was just informed that these boats need alot of trim to free up. i have yet to run max trim.

daredevil, if you could, same basic deal but a little diff. 5400 rpm---1:54 trans gear ratio---18% overdrive/drive ratio and a 17x23 4-blade wheel, approx.speed ? thanks in advance ! ps: ya & 3-blades don't work well.



CORRECTION

67.20 BIG Daddy :ernaehrung004:

I've got an old Cigarette Flat Deck with Arneson Surface Drives, and the general rule of 200 rpms per inch of pitch applies but diameter, rake angle, and number of blades can't change also.

My boat tends to like bigger diameter, many blades, and high rake angles.

Kris Vogt

I forgot to post my new numbers but it seems still too much slip. 17 x 29 4 blades again at neutral trim.

67.9 @4800

if i trim up all the way i think i can turn them 5100 BUT i also think it will prolly slip more.

I am also thinking more diameter less pitch like a 18x 27 or 28 would be perfect!!!

I think thats with i questimated ?! LOL ( the prop size)

I would also think a 18X28 , and go from there .

But the slip # came down to 12% which is not bad at all !

slip
 

Bill, how are ya doin ? Thanks for the est. same set up as car-biz except kamma drive 18% over w/ 1:54 trans 17x23 prop 33-Sutphen seen 80+ what are u-fig. on the slip and @ say 5600 what is your est. mph daredevel jump in if u-wish thanks guys ! :drink: ps: ya ya it's a SKATER NATION :ernaehrung004:

Thanks for the help DD:ernaehrung004:

ICE i have my 16-1/2 x 24's i need to get rid of if you know someone look give me a shout!

There is now way you seen 80+ with that prop and ratio, if so you turned your engine at almost 7 K ?!

Around 69-70 Mph @ 5600 ,with that prop and ratio .

What engines do you have ? Your slip# is bretty good !
But you need a bigger prop ?!

I think its supposed to be 1.154 trans ratio.

my twin discs are stamped 1.54 right on the tranny. My drives are 1.1. With Kammas you can change gear sets in the drive for overdrive or underdrive.

In ICE's case i agree if he seen 80 + befor. LOL

then he would of seen them at around 5000 RPM with a 14-16 % slip.

Aren't high slip #'s the norm on Surface drives ????

They shouldnt be !?

dd
 

twin 548ci 645hp dyno and thanks 4-the responses :cool:

Surface drives give high slip numbers on most hulls other than extremely efficiant hulls. ie catamarans. People will argue that but I see it every other day. They do have their advantages though.

Keep the 17x29 4 blades and let us have a crack at them. I know we can improve the slip and speed numbers.

short or long style hubs ? I know a guy lookin for the early model short style hub props as far as "I am concerned" a set of 17x23 and 16.5x24 are prob very close, thanks :drink:

Bret,:cool: you want to mess around w/my 17x23's :cool:

Bret,, thats what i ment,,,, he runs 17 X 23 !!!!!!! To small .

But i need to actually have you take a look at my prop.

My slip # is up like 18-20 % ????????? And the hull is perfect straight.:eek:

Brett, or DD with a 1:54 ratio trans and an 18% over drive/drive "for round # sake" @ 6000 rpm engine speed, the out put of trans. would be 4000 that is to say: 3 rev. of engine speed produces 2 rev. of trans. out-put X 1.18 would produce a prop. shaft speed of approx:4720 with a 17x23 wheel and say a 10% min. slip what do you guys fig. for mph ? ps: just 4-kicks and giggles Ritchie Sutphen says that his boats, back in the day ran excellent w/Kaama surface drives ! Thanks again.

The # i figured out is around 82 MPH ??????????

But i could be wrong.:party-smiley-004:

long hub here is a pic of them.

Brett i talked to you about 3 weeks ago about this. Problem is the gent i borrowed the props from won't let me buy them these are his spares. Unless...........Maybe i'll try to ask him one more time:D

car biz, send me a PM w/price if u-wish on the 16.5x 24's, I might consider a spare set, thanks for the photo. so your look-in for a long style hub/19 spline shaft, same as a #3 uses around a 17x27 or so correct ? ps: u-puttin more hp in that hull ?

dd thank you very much I will chase u-down in KW

cb ask 4-charlie on 17x27 4-blades OSO add#26153 ph:410-463-9900 or 410-228-1435 good luck, catch ya later :cool: let me know what he says.

Dont chase me,,,,,,,,,i may be to fast .LOL

Just stop by .HAHA:drink:

:ernaehrung004: u-better win in your class I'll only b-shootin ya with a lens in KW lol :eek:

i really want a 18 x 27 or 28 i think i can get the slip down with the 18 compared to the 17.

I don't think i will be ading anymore power yet. I just had these motors done this year. I may add late but not right now:drink:

18x27/28
 

keep my ;) open 4 ya

I'CE sent ya a PM

got it
 

Thanks for the info. givin it some thought, not an emergency @ my end, did u-leave a # to reach ya ? u-goin to the Keys this wk. 4-the races ? :drink: ps: my buddy had the same basic set up as u-do. Koool.

got it
 

that PM was on the prop.$ correct ?

Yup i will PM ya my number! I am not in a real big hurry just want to be able to get some soon. I've got to get BOATMAN302's spares back to him.:drink:

Jer. Am In Mexico Now Till The 12th Will Call When I Get Back. Any News On Anything. Bruce

An original Kaama Formula has also inbuilt rocker in the hull which a stenrdrive sister doesn´t have so thats why the trim is needed.
A Surface drive doesn´t give hardly any bow or stern lift compared to a sterndrive.