40 Outrigger Props

[ClayGlover]

OK. I see you guys recommend 16 series for 40 hydro heat racing. What is the trick to get a stock Mac 45 to turn a 1655. My fastest prop so far is a cut down pitched up 1460, and can't get the AB1655 on pipe. 1457 is all acceleration and no top end, but very driveable. This is testing with various pipe lengths between 9.75" and 11". 3 year old version on motor and the p/s & bearings are fine with about 3-4 gallons through them. Brown parabolic at 10.25". Have not tried any other pipes on this boat so various pipe recommendations would be great. It's the older style pipe with the smaller diameter stinger at 3/8" I.D. and baffle is drilled out to the same I.D.. If I go shorter on the pipe, I don't have enough bottom for racing. Strut depths I've tried make little difference with the 1655 being able to pipe. There is about 1-2 degrees negative angle at the strut. Have not tried level strut yet, but that will be done next trip out. I'm thinking it's the pipe.

It's a 4.75 lb 45 SG with 3 rears running 60%. Oh, and the old style flat-backed strut (speedmaster type), not the extended strut they now run.

 

[Don Ferrette]

Almost sounds like the boat is too "tight" on the water. How does the boat run with less negative in the strut?? :unsure:

 

[ClayGlover]

I know there are lots of factors it could be.

I do feel the boat has to much lift in the rear setup this way with strut angle. That will be the first thing I do is try a level strut setting. The boat has a tough time in race condition water or "medium chop". When it comes loose in a straight, it flies nice and level when airborne, no blow overs. No hopping either. The problem is when it gets loose in rough water, it likes to submarine the front. I believe it's getting loose, then when the prop comes down on a wave crest, the prop is popping the back end up and "seesaws" the sponson tips into the water ahead. I have no problems on smooth water other than not being able to swing the 1655. If you will, take a look at the picture I attached below.

The strut on the boat is a round bottom tidewater strut that extends into the ski. Because of this, it makes angle adjustment difficult because the ski's interior has klegecell surrounding the stuffing tube and the front taper of the strut is hitting the bottom of the ski. The solution is removing some foam and allowing room for bending the tube, and possibly trying a different strut. That's why I have not been easily able to test a zero strut angle yet because it's not cooperating with me that way. That's easy enough to do and if strut angle is the problem, I'll be very happy and hopefully gain speed to boot.

Front sponson AOA seems to be fine and interestingly this SG has no enlongated boom tube holes in the tub for AOA adjustment with shims :blink: . Maybe that's standard from cmd? That can be changed, but I've seen no need at this point.

OK, so I'll level the strut. If that don't work, I'll try different pipes. If that don't work, I'll try a new motor I guess....

Any clues regarding the submarining?

Woops, here's the picture-

 

[Preston_Hall]

I believe it's getting loose, then when the prop comes down on a wave crest, the prop is popping the back end up and "seesaws" the sponson tips into the water ahead.

Front could be too tight or too much negative in the strut or both. Try zero strut angle, 1 degree neg. max. Also, see if you can get the flat bottom strut.

Front sponson AOA seems to be fine and interestingly this SG has no enlongated boom tube holes in the tub for AOA adjustment with shims . Maybe that's standard from cmd?

That is standard, but not to mean you shouldn't do it if necessary. Andy had me slot the rear boom hole on the 21 SGX.

OK, so I'll level the strut. If that don't work, I'll try different pipes. If that don't work, I'll try a new motor I guess....

John Finch brought his new MAC/SGX 40 out and it runs well (high 70's, low 80's). I wouldn't get too hurried with the motor just yet.

 

[Chris Attebery]

Clay,

Here's the setup for that hull:

3 or 4 .025" shims under the front boom.

Strut should be as deep as it will go and 0-1 degree negitive. 1 degree is the same angle as the center shoe. You can lay a straight edge on the bottom of the shoe and the strut should be flush with the straightedge or a slight gap at the rear.

A round bottom strut is what Andy sells with the boat, they work fine.

In my experience most SGs are too tight on the water at the stock settings. With these sponson settings a flat strut will make the boat slightly flighty at the end of the straightaway. The 1 degree strut setting should be a good all around heat racer. Note that with a 2" long strut there is a .035" difference per degree. Slight changes will make a big difference.

Give it a shot, let us know what you think.

Chris

 

[Chris Wood]

one other thing i noticed on your strut. you have the short strut. i would reccommend a extended strut. you prop is probably in front of the rudder and that is no good.. causes crazy things and it will make it harder to launch because you are spraying directly on the rudder

where a extended strut is behind the rudder and out of the rudder path.

hope i helped

chris

 

[Don Ferrette]

"A round bottom strut is what Andy sells with the boat, they work fine."

True, but the new strut with the longer trailing length seems to work better. We found that out on John's 40. He had a strut like yours & switched to the new one, much better! I'd have Andy send you just the strut blade then set it like Chris says.

"3 or 4 .025" shims under the front boom. "

Not necessarily in all cases. I've got 4 SGX's & every one is a little different as to shim amount (and placement). Put the boat on your set up board & get tub level with board (measuring at engine well) then set the top of the sponsons level with board. This will get you very, very close. A digital level is the shiznit here but if you take your time with a small torpedo bubble level you can get it. Obviously you want your set up board dead on level before you start if you use the bubble level method. Then once you get to the pond you can tweak it a little. Go easy on adding shims as you do since these hulls are more sensitive to AOA changes than most (1/2 degree AOA change was worth 5 mph on my 20). You will find a 1/2 to 1 degree max is all you'll need on the strut & the straight edge method Chris mentions will put you where it should be. With the longer CMD strut all mine are 1/2 degree or less. Hope this helps! B)

 

[ClayGlover]

OK, I've got a digital level here. So you say set the sponson tops at zero degrees relative to the level tub bottom. Thanks, I'll check it right now and we'll see where I'm at.

I've been looking at the new style strut, I've been delaying the switch due to having to replace the shaft and dog as well due to the added length. I'll give it a shot as I haven't liked the current strut setup from the get go. The tidewater stuff is great, just the combination of the way it's put on this particular boat makes adjustment difficult without some changes. Gotta place a long overdue order with him anyway.

Thanks guys for the advice, and I'll get back with a follow-up in a couple of weeks. B)

 

[Don Ferrette]

" OK, I've got a digital level here. So you say set the sponson tops at zero degrees relative to the level tub bottom."

Not quite. Zero out your set up board. Then set tub to zero (measuring top of tub along side engine). Then set sponsons to zero, all relative to the zero board.

 

[Mike Larson]

hey don! while youre in the rigger helpin mode wondering if you could help me too... 1st rigger for me, 21 roadrunner , cmb tt power only gettin 30s from it its on the pipe screamin, hops in the corners alot. have strut adjusted all ways from sunday, no better, worse or forget it... how, do you make a set up board? if it sets in my stand (the tub) level on a level surface, can i use it? is it a general rule of thumb to have the tops of the sponsons level, with all else level too? when you shim the booms, install them under where the bolt in the tub? christ, i dont know what the angle of attack of my boat is, must be close it rides well in the straights, will take rough water well, dont know...... the rear sponsons are not adjustable, or i think they need lowered? mark shound helped me with props to get where im at (speed) would like to tame this thing a little, i got tunnels beat it! this may be an old school boat, im thinkin, i know sgs rock! any input? thanks mike

 

[TomMoorehouse]

have you read this article mike?

http://rcboat.com/setup.htm

 

[Terry Keeley]

Ooops, wrong thread...

 

[Don Ferrette]

Tom beat me to it. The set up shown in the link works rather well except on the R/R's I ran the strut down flat on the set up board & the rear sponsons 1/8" up as shown. Also I will drop the front tips of the rear sponsons to about 3/16" above the tub bottom. This softens the rear sponson AOA & makes the boat easy to launch. Another big improvement to the R/R boats is to get one of Dick Tyndal's turn fins, really helps the boat speed in the corners. The Roadrunners are still good heat race boats.

 

[ClayGlover]

one other thing i noticed on your strut.  you have the short strut.  i would reccommend a extended strut.  you prop is probably in front of the rudder and that is no good.. causes crazy things and it will make it harder to launch because you are spraying directly on the rudder
where a extended strut is behind the rudder and out of the rudder path.

hope i helped

chris

Well, I thought about what you mentioned. The trailing edge of the rudder is even with the middle of the prop's hub. At speed I'm sure the rudder is past the thrust cone. Do you feel it's an issue this way?

 

[Stein Tumert]

I used that strut on my old Pinckert Daytonas. They worked OK there. I agree with Don that you should get a new strut from Andy that is made for the SG and then set up as advised. Should improve things.

 

[shoboat]

Clay,

New strut from CMDI, less than .7 degrees of strut angle. And then try to

level your strut as much as possible. Try a 2216 or 2116 and you will be

happy,I think the new ABC Props will be much faster than the 1600 series.

On a 21 boat over the weekend we were able to pull almost twice the cup

on the 1718 prop than anything else. We picked up about 5 to 10 MPH in

heat race trim alone. The 45's should be just as easy too.

Just A Suggestion,

Mark Sholund

 

[ClayGlover]

Mark,

Is there a chart online for the NEW abc props? [never mind, I found it] How much for a s&b 2116? Any thoughts or feedback on the 2414 cut down? Thanks

 

[AndyBrown]

Clay,

Not 100% sure, but from what I can see, looks like you have an original (1996) SG. From the short view of the rears I can see a very high AOA. 5 degrees is what the 1996 SG had.

This boat will run well, but the strut must be nearly level. I can see the center rear has been added later. That may be having an adverse effect.

There is an original SG 67 racing and leading the points race in NAMBA dist. 9 using the same High AOA rears, but without the center. So the boat is still original and it runs well.

Anyway, my suggestions are: #1 Make the Strut flat. If the boat continues to stuff you have two choices. A. remove the center rear. or B. replace the high AOA rears with the new low AOA rears and maintian the center rear.

A. would be the no cost choice. B. will cost a set of new rears.

Either way I would recommend our Anti-walk strut. And yes it does reduce prop walk when running the big high pitched props.

Andy

 

[Mike Larson]

thanks to tom, don and all for the info, great forum... may have to post more often! mike

 

[AndyBrown]

Clay,
New strut from CMDI, less than .7 degrees of strut angle. And then try to

level your strut as much as possible. Try a 2216 or 2116 and you will be

happy,I think the new ABC Props will be much faster than the 1600 series.

On a 21 boat over the weekend we were able to pull almost twice the cup

on the 1718 prop than anything else. We picked up about 5 to 10 MPH in

heat race trim alone. The 45's should be just as easy too.

Just A Suggestion,

Mark Sholund

Mark,

When you say the new ABC props will be much faster than the 1600 props, how much is "much"?

"almost twice the cup" ? Normal cup for a 21 is 3.2" to 3.6". So I assume that means you are pulling 6.0" to 7.0" ??

5 to 10 mph?? H-7's, 1445's, 1450's. and few other props have been set up on heat race boats to run in the mid 70's. Does this mean we can now expect to run mid 80's with our 21 riggers. Or mid 70's for the average guy who was running 65.

I'm not knocking the new ABC props, we are testing them too. Just wondering about all these BIG numbers you are talking here.