What props to run on a .21 hydro?

[jaxracer]

Hey guys, I've never run a .21 hydro before and I was wondering what props you guys run on them? I'm looking at all aspects from heat racing, to time trials, to straightaways.

I'm not looking for you guys to give out all your speed secrets, just something so you can put me in the ballpark with a list of propellers that I should look at trying that you know are fast and that work.

Thanks,

-Mitch

 

[John Knight]

Mitch,

Short answer as I do not know specifics about hull, engine, pipe, etc., are as follows for heat racing:

H-4

H-5

H-6

H-7 (preferred)

1445 pitched up

1450 reduced to 46mm (preferred)

These are my preferences but they widely shared among many 21 rigger pilots.

John

 

[shoboat]

Mitch,

It will depend on what boat, motor, and pipe that you are running.

They all work well with the right cup, pitch, and diameter for your

Set up. Don't forget about the ABC 50 x 69 also.

Have Fun Testing,

Mark Sholund

 

[LarryConrad]

Mitch,

Like Mark already mentioned a lot depends on the hull and engine choice. Novarossi's will pull a larger diameter prop than a Mac or CMB Valvola will. I run ABC H7's 50x69's, and Octura 1450's on my Nova powered Blackbird. When I get my Mac powered SGX One wet next spring it will have a smaller wheel on it, most likely an H4 to start out with.

 

[TimothyJones]

Mitch,

Mark will Help you if given all the info above and guess what>>>>>

He will respond quickly,answer and you don't have to track him down and send 20 e-mails for a response.

Tim

PS I use a cut down. pitched up 1450

 

[Ron Jefferson]

ABC 50X69 with 3.3-3.6 depending on hull/motor and how well it launches.

Ron

 

[happybradboating]

I know everyone suggests lifting props but I have not had much luck at 4,500 above sea level. I have used 437/3 & 440/3 with different cupping & with or without relief notches when running a 3.5 Roadrunner & 3.5 JAE.

Brad

 

[jaxracer]

This is some good info. Thanks guys for all the responses. I think you've given me a pretty good idea of what direction I should go in.

Appreciate it,

-Mitch

 

[Daniel Richard]

I've never had an issue with my MAC or Valvola wanting to pull a prop. I ran an H-10 on my MAC powered Jag 2 and I am running a 1450 on my Valvola powered Blackbird. I've gotten really good speeds out of both setups. So far the 1450 has been the fastest on the Blackbird but it seems like I could use a little more load at times. Get a prop from Mark and he will get you really close to where you need to be . After that all you need is a little fine tuning to get it perfect.

 

[DeanJohnson]

Does anyone know the true stock diameter and cup of a 1450?

Thanks,

Dean

 

[anthony_marquart]

I think they probably vary about .75mm... raw cast,.. poor tolerance!!!

 

[shoboat]

Dean,

I just measured 4 -1450's straight out of the bag. They were all very close

to these measurements raw:

49.06mm to 49.03mm in diameter

2.90"- 2.73" of T.E. cup @ .7 radi

2.73"- 2.65" of C.O.B. pitch on 3/16 step on the gauge

Some varied just a little bit, and you will lose about .3mm

in diameter when you true them up on a lathe and finish the

balancing on a Frank Orlic jewel balancer like I do.

These are with a Steve Wood pitch gauge.

Mark Sholund

 

[DeanJohnson]

Thanks Mark,

Much appreciated.

Dean