Props for .12/.15 hydros

[Jerry Dunlap]

Greetings,

I'm working on a Sport .15 hydro project and have been playing around with props. The motor is a pull start 15 with a tune pipe - the same engine/pipe as in the Nitro Hammer - guess who's Nitro Hammer is missing a motor and pipe? The boat has a flex drive system and the strut mounts to the transom so the prop is in back of the transom.

Two props that seem to work o.k. are a X438 that has been reduced to 36 mm diameter and back cut and a Y536 that has also been reworked.

The motor is pretty mild and I haven't been able to swing a full X438.

Jerry D.

 

[Chester]

I started with a Y536 for a OS12CV with MACS .15 quiet pipe, 20% nitro

Now running with a X637 and tested with a X1445.

X637 seems to be "WILDER" while X1445 shows MILD.

 

[Eric Perez]

I thought the Nitro Hammer had a .18 engine. Not that it really matters -but the oversized small-blocks tend to have better torque than their sport .12 conterparts.

As far as what props work for a "sport" pull-start small-block?

It depends on the design of the rear-end. With rear-sponsons or a single ski you will be able to swing S215, S220 and X438.

On my .12 pull-start catameran I was only able to go up to a Y535 and the engine boggs-down a bit. It ran best with an X432 or X435 performance with inexpensive plastic Y534 was also good.

That's just my experience.

 

[Don Templeton]

Hammer is running an OS .12 TR-(P) " TURBO", rear exhaust, non pull start.

 

[Eric Perez]

I think Jerry is making reference to the Hobbico Nitro Hammer mono. This is a pull-start sport model w/ a glass hull.

 

[_laxmasta2039]

The OS .12 TR has got to have some pretty impressive stats to be worth it's price...tower is the cheapest place for small engines i know of and it is 200 bucks there!! My FF .12 rigger with a KB .18 in it will start with a standard, nothing-but-B/S p215 when the ponds thaw, though that seems a little big for the engine [it's what KB recommends] odd that my .21 and .18 will be pushing the same prop.....

Joe

 

[Don Templeton]

Joe,

I think the TR's are the first OS car .12's to come out with the seperate head button and then the newer Turbo version added a deeper head button to accept the turbo plugs as well as a 5 port sleeve. Also I think Hammers engine might have been blue printed. I really think this engine is a very good value for the price and avialibility of parts and service. That Siro (or however you spell it ) from Trinity/Rossi looks like a super engine for the price but I don't know much about it other than the specs look great!

Sorry guys! I didn't know there was a boat named the Nitro Hammer! :-[

 

[Jerry Dunlap]

FYI,

The boat I'm working on is 28" long with a wood frame center section and WOF(what a surprise!!) sponsons and non trip sides, and a balsa wood cowling. Don't know what it weighs, not really light.

With a cut down Y536 it hit 35 mph on 30% fuel. Infact, I even blew it off the water. Might need to increase the prop thrust angle. Not running rear sponsons - but might try them.

Jerry D.

 

[waterbug]

Just thought I would throw this out . There are some Black Pixi's brand new on ebay in the 180.00 range, straight out sale!!! ;D & some Black Pixi Outlaws too !!!