Prop / Turn fin

[DeanJohnson]

Hi Guys,

Looking for some insight regarding the proper set up for prop and turn fin on a 21 Hawk.

1) What's the best depth to set the turn fin and what degree of angle would give the best results? How far back should the turn fin be set in comparison to the length of the hull.

2) What's the best prop to run?

The boat will be running with a CMB 21LS motor, MAC pipe set at 7.5" from center of the head to the weld, and 40% nitro.

Your comments are appreciated!

Dean

 

[norm j]

dean your best bet would be to talk to gary prusse or steve ball,they have real good running hawks and have the correct set up instructions on that hull

norm j

fmbc

 

[LH7018]

Try going here for set up info also.

 

[DeanJohnson]

Thanks guys,

I've tried the 1450 prop that the website listed above recoments, however, the motor doesn't like the load. I bought a 1445 today and will give that a try this weekend.

Does anyone know about the H4 prop?

Thanks again!

Dean

 

[John Knight]

Dean,

The H-4 and H-5 props are both excellent. The 5 is slightly larger than the 4 (tad smaller in size than the 1445) and can potentially give you more speed if your engine can take it. The H-7 is even faster but takes a well set up boat and fast engine to pull it for good speed.

John

 

[shoboat]

Dean,

The 1450 needs to be reduced to 46mm or just run a: H-4,5,6,or a reduced H-7,

they all will work well. Stock cup varies with each propeller, and that is most

likely your problem. I have them all either Raw or Finished. Keep the cup low

and you should be able to pull them all with good RPM. 2.81" to 3.46" is enough.

I know Steve runs an H-4 on his boat depending on water conditions.

Good Luck Testing,

Mark Sholund

 

[AndyBrown]

dean your best bet would be to talk to gary prusse or steve ball,they have real good running hawks and have the correct set up instructions on that hullnorm j

fmbc

DITTO!

 

[rctinman]

Hi Guys, Looking for some insight regarding the proper set up for prop and turn fin on a 21 Hawk.

1) What's the best depth to set the turn fin and what degree of angle would give the best results? How far back should the turn fin be set in comparison to the length of the hull.

2) What's the best prop to run?

The boat will be running with a CMB 21LS motor, MAC pipe set at 7.5" from center of the head to the weld, and 40% nitro.

Your comments are appreciated!

Dean

Hi Dean..

The turn fin to use is from David Preusse. You can get it from Gary. The leading edge of the turn fin is about 1/8th. of an inch from the back of the sponson. does your sponson have a carbon fiber turn fin spar, or is it the stock spar? I don't measure the angle of the turn fin. I look at the bend of the turn fin in relation to the bottom of the tub. As you sight across the bottom of the tub, your bend in the turn fin should be slightly lower in the back.

As far as props go, I would start out with a stock ABC H4, then move up to an ABC H5. I heat race with a H5, and a H7.

Hope this helps!

Steve Ball

 

[DeanJohnson]

Hi Steve,

I do have the carbon fiber turn fin spar. I also bought the additional "modified" set up sheet Gary supplies and will set the boat based on that.

I went out yesterday and got the H4 and H5, and will try those along with the 1445 this evening.

Are you aware of the pitch difference with the H4-5 compared to the 1445? Is there a tool one can buy that measures the pitch of props and how is the pitch of stock props altered?

Thanks to all for the assistance!

Dean Johnson

 

[rctinman]

Hi Steve, I do have the carbon fiber turn fin spar. I also bought the additional "modified" set up sheet Gary supplies and will set the boat based on that.

I went out yesterday and got the H4 and H5, and will try those along with the 1445 this evening.

Are you aware of the pitch difference with the H4-5 compared to the 1445? Is there a tool one can buy that measures the pitch of props and how is the pitch of stock props altered?

Thanks to all for the assistance!

Dean Johnson

Dean, the set -up sheet from Gary is very good information!

I don't know the pitch difference between these props yet, but I can say that the h-4 prop will have the least amount of load on your engine, but will get your Hawk moving so you can get your set-up refined. Then you can move up in prop size to get the most speed. The best prop pitch guage out there is from Woods racing. It's a bit pricey, but you'll never need an other one, ever.

Steve