2010 Stock Outboard Class: Mini Formula 1

[SEASTALKER]

As you no doubt know the 25hp and 30hp Tohatsu 2-strokes are really the same motor with a capacity of 429cc.

The lower unit reduction ratio is 1.9166:1 which gives a propeller speed of 3600rpm and a theoretical maximum speed for 18" pitch of 61.36mph.

You only have around 2.2% slip and you are achieving the ultimate speed!

Are you going to circuit race the boat?

Peter

[voodoo]

we did race the boat with great sucsess it also set the australian 25hp kilo or speed record with an average speed of 92.36kph over 2 1km runs we could have done better but i was to windy on the day,that was the day it did 96.6k but i could not hold that speed without going 4 a kite ride the wind was blowing across the coarse at 25 to 30 knots as you can see in the two photos of that day ,the new class mini f1 sounds like alot of fun good luck !

[Infoless Racer]

how can one come so close to the theoretical speed? Must be VOO DOO

[voodoo]

i don't care much for theory,96.6k slip or no slip thats what the G P S said and im sticking with it ! theres i guy in queensland that did 97 plus around the same time pulling roughly the same revs with some sort of 4 bladed 17p cleaver so whats his theory ?

[Ron Hill]

In THEORY all NASCAR cars should be even, but Jimmy Johnsons seems to have an edge.

Speed theories are usually just that. Many times our props run faster than theory. Why? Whoever measures them doesn't include the cup or doesn't measure them correctly. Or a tachometer being off a few hundred RPM's...

If props worked as "THEORY" would have it, you'd probably only need one prop to fit all.

Sean McKean went 130 MPH in the kilo last fall. I'll be it is hard to figure his speed within 10 MPH.

I once broke two World Records in one day, both 1:1 gears, one motor was a 30 HP, one was a 55 HP. (66 MPH in the 30 and 74 MPH with the 55. Explain that theory.

In the spring of 1967 and Modesto, I broke three World Records with the same prop, 550 cc, 750, cc and 1100 cc. That same year I won the 500 CC championship on a hydro, and then the 750 CC National Championship on a runabout same prop.


We had a prop JUST LIKE THE GOOD one.......except 5 MPH slower!

[voodoo]

what type of props are u doing at the moment ron,in regards to 25/30hp toey/merc/mariner/nissan.i think these guys with there mini f1 class will have loads of fun,but they need better props.

[david bryan]

what type of props are u doing at the moment ron,in regards to 25/30hp toey/merc/mariner/nissan.i think these guys with there mini f1 class will have loads of fun,but they need better props.

what hight is the prop shaft in relation to the lowest point on the bottom

[voodoo]

it was about 20mm below the floor and 110mm above the bottom roughly

[david bryan]

it was about 20mm below the floor and 110mm above the bottom roughly

is there any rules on motor hight

[voodoo]

no that was 550cc super sport ,its only restricted by engine capacity 25hp open hull class had no motor height limits,you were aloud to put a nose cone on the gearcase this helped with engine cooling.