rudder notch for proper water cooling

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brett english

Well-Known Member
Joined
Aug 13, 2010
Messages
845
I need some advice here on the rudder inlet hole(water pickup)..do you guys file a notch in the leading edge to get more water flow?? or leave it stock? what about in the turns or if you need to turn left..will water still cool the motors?? and also what does it do to the attitude of a rigger as far as kicking the rudder blade back or pushing in..

thanks
 
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Hello Brett, as far as I know, I was the first to run the water pickup in the rudder, on the west coast I was anyway.

I put the water pickup hole on the right side of the blade for several reasons. First was to push the maximum amount of water thru the engine when it needed it the most, when it was heavily loaded in the turns. Second, I trim my boats to pull slightly to the left with the rudder dead straight when going down the straight-a-way. To me, this makes the boat more stable and easier to drive and also makes sure that the engine is getting plenty of water all of the time.

Once Mr. Bill McGraw and I were talking about the placement of the water pickup on the left and the right of the water blade and he told me that the reason that he changed the pickup hole on his SpeedMaster rudder blades from the right side to the left side of the rudder blade was that some of the boaters were experiencing the engine not getting enough water and running hot. This was caused by the boaters using the rudder, with a lot of left trim, to make the boat go straight, and this uncovered the water pickup hole when it was on the right side.

Just different ways of setting up the boat with different results.

Charles
 
I need some advice here on the rudder inlet hole(water pickup)..do you guys file a notch in the leading edge to get more water flow?? or leave it stock? what about in the turns or if you need to turn left..will water still cool the motors?? and also what does it do to the attitude of a rigger as far as kicking the rudder blade back or pushing in..

thanks
My Twin gets plenty of water thru a Speedmaster blade. If your running Hot with a Big Engine? Things to consider. Pipe & Stinger Size, Fuel delivery, Are you running Large Water lines? if all of this checks out Increase the water outlet holes in the cooling head. I have 2 sets in most of my engines. small & large, I plug what I`am not using for that season. Consider the ID of the water fittings what the Mfger had specked for the engine that orginally came with the engine. Normally it would allow for MAX cooling. You will need to let MORE WATER OUT to Flow More water. I guess the water in FL Have finally warmed up?????
 
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I run speedmaster rudders on all my boats and i notch the rudder leading edge at the pickup and never had a problem anywhere on the course.some old nitro guys told me about this and i never looked back.
 
I need some advice here on the rudder inlet hole(water pickup)..do you guys file a notch in the leading edge to get more water flow?? or leave it stock? what about in the turns or if you need to turn left..will water still cool the motors?? and also what does it do to the attitude of a rigger as far as kicking the rudder blade back or pushing in..

thanks
My Twin gets plenty of water thru a Speedmaster blade. If your running Hot with a Big Engine? Things to consider. Pipe & Stinger Size, Fuel delivery, Are you running Large Water lines? if all of this checks out Increase the water outlet holes in the cooling head. I have 2 sets in most of my engines. small & large, I plug what I`am not using for that season. Consider the ID of the water fittings what the Mfger had specked for the engine that orginally came with the engine. Normally it would allow for MAX cooling. You will need to let MORE WATER OUT to Flow More water. I guess the water in FL Have finally warmed up?????
thanks for that info guys... Joe also what about rudder blade angle?? by pushing the blade in what will that do to the boat? or pulling the blade back? what makes a rigger run tighter on the water as far as position of the blade..
 
Brett are we talking Single engine or Twin? The Turn Fin wets up the Sponson so the boat can turn hard. You Must keep the Turn Fin HOOKED UP in the corners for this to happen. Also We have went to a 6/32 steer rod & 5755 digital 1/4 scale servo on all Twin Engine boats.. Tucking the rudder under works on a mono But it dont have a turn fin like a rigger.
 
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Brett are we talking Single engine or Twin? The Turn Fin wets up the Sponson so the boat can turn hard. You Must keep the Turn Fin HOOKED UP in the corners for this to happen. Also We have went to a 6/32 steer rod & 5755 digital 1/4 scale servo on all Twin Engine boats.. Tucking the rudder under works on a mono But it dont have a turn fin like a rigger.
i agree 100% that a 4-40 rod will not be enough to turn a twin without it flexing..i solder a brass sleeve over the 4-40 rod for strength, but a 6-32 rod would be perfect, and yes ralph insisted on me using a hitech 5755..great servo!!

so i guess its best to leave the rudder perfectly vertical on my twin??
 
Brett are we talking Single engine or Twin? The Turn Fin wets up the Sponson so the boat can turn hard. You Must keep the Turn Fin HOOKED UP in the corners for this to happen. Also We have went to a 6/32 steer rod & 5755 digital 1/4 scale servo on all Twin Engine boats.. Tucking the rudder under works on a mono But it dont have a turn fin like a rigger.
i agree 100% that a 4-40 rod will not be enough to turn a twin without it flexing..i solder a brass sleeve over the 4-40 rod for strength, but a 6-32 rod would be perfect, and yes ralph insisted on me using a hitech 5755..great servo!!

so i guess its best to leave the rudder perfectly vertical on my twin??
yes vertical, The length of the rudder is about all you can make a improvement on. (Dont cut too short) WE run 60/90 speedmaster blades & about 4 1/2 length under the tub. The 5755 & the 6/32 rudder turn rod & a Sub - C 2000mah battery 6 volt ( made by batteries plus) has corrected any turning problem I ever had with the twin. Also works very good on a F mono...... WE set the twin up to run in the RACE CHOP.... seldom ever see any smooth water.
 
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I had a boat that always ran hot when the rudder diection changed with either left or right hole. I ended up making a water entrance point on the opposite side of the inlet and the engine cooled no matter what. Almost all my rudders now have a pickup on both sides of the blade. Just what I did to solve the problem. I make the second hole with a dremel 1/8 inch carbide bit and make it a bit higher or lower that the original that is on the opposite side. It leads to the same end point at the rear of the blade as the original. I have also filled the intake hole and drilled a new one higher up on the blade for record trial runs with the rudder just behind and to the right of the prop so that the pickup is above water level, but the propwash fills the hole. Not recommended for heat racing.
 
Why not just run a prop blast pick up and on a twin just run 2 theres no drag and if you run the boat into shore and its still running it won't burn the motor up as long as the prop is still in the water , if its not well you have more problems , i have always used this set up with no issues .

Good luck
 
I would think that would add quite a bit more drag when compared to a rudder pickup. Isn't that pickup "dragging" in a water stream that is going the other way (to the rear) ?
 
I would think that would add quite a bit more drag when compared to a rudder pickup. Isn't that pickup "dragging" in a water stream that is going the other way (to the rear) ?

ive never had a problem with propblasts on my boats. The drag it may cause, is quite offset by the drag lost from going from a .250" wide blade in the water to one @ .060-.080".

I reprofile the pickup and notch the LE on all my rudders. No cooling problems and always gets water no matter which way its turned.

R42 036.jpg
 
Why not just run a prop blast pick up and on a twin just run 2 theres no drag and if you run the boat into shore and its still running it won't burn the motor up as long as the prop is still in the water , if its not well you have more problems , i have always used this set up with no issues .

Good luck
First off, if you worry about running into the shore you need to ask yourself what is causing you to think that way. Waterflow is the least of your worries. LOL!
 
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I would think that would add quite a bit more drag when compared to a rudder pickup. Isn't that pickup "dragging" in a water stream that is going the other way (to the rear) ?

ive never had a problem with propblasts on my boats. The drag it may cause, is quite offset by the drag lost from going from a .250" wide blade in the water to one @ .060-.080".

I reprofile the pickup and notch the LE on all my rudders. No cooling problems and always gets water no matter which way its turned.
Different strokes for different folks.......I also have rudder blades that are less than .060 thick.....with water pickups in them. They furnish plenty of cooling. :huh:
 
I would think that would add quite a bit more drag when compared to a rudder pickup. Isn't that pickup "dragging" in a water stream that is going the other way (to the rear) ?

ive never had a problem with propblasts on my boats. The drag it may cause, is quite offset by the drag lost from going from a .250" wide blade in the water to one @ .060-.080".

I reprofile the pickup and notch the LE on all my rudders. No cooling problems and always gets water no matter which way its turned.
Different strokes for different folks.......I also have rudder blades that are less than .060 thick.....with water pickups in them. They furnish plenty of cooling. :huh:
Right on. If your boat is heavily loaded you will need more water flow, but if things are purring lightly on top of the water it doesn't take much to cool off the engine.
 
Why not just run a prop blast pick up and on a twin just run 2 theres no drag and if you run the boat into shore and its still running it won't burn the motor up as long as the prop is still in the water , if its not well you have more problems , i have always used this set up with no issues .

Good luck
First off, if you worry about running into the shore you need to ask yourself what is causing you to think that way. Waterflow is the least of your worries. LOL!



I've seen this happen and the guy's motor didn't burn up on him , thats all im sayin

A what drag do you get from a prop blast when its no where near the water it's near the top of the prop , there is no where near the drag as a rudder pick up and it pull's the boat to the side the rudder is on , if i'm wrong i'm sorry but there's some really fast guy's out there that run prop blast exspecially on SAW boats.

PS. John i don't worry about running my boats on shore , sometime's it just happen's :eek: :( :D :D don't tell me its never happened to you before B)

In my oppinion i like the prop blast over the rudder water pick up , thaz all :p
 
I was at the hobby shop today and saw a rudder with a slot on both sides and thy met at the intake hole.
 
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Why not just run a prop blast pick up and on a twin just run 2 theres no drag and if you run the boat into shore and its still running it won't burn the motor up as long as the prop is still in the water , if its not well you have more problems , i have always used this set up with no issues .

Good luck
First off, if you worry about running into the shore you need to ask yourself what is causing you to think that way. Waterflow is the least of your worries. LOL!



I've seen this happen and the guy's motor didn't burn up on him , thats all im sayin

A what drag do you get from a prop blast when its no where near the water it's near the top of the prop , there is no where near the drag as a rudder pick up and it pull's the boat to the side the rudder is on , if i'm wrong i'm sorry but there's some really fast guy's out there that run prop blast exspecially on SAW boats.

PS. John i don't worry about running my boats on shore , sometime's it just happen's :eek: :( :D :D don't tell me its never happened to you before B)

In my oppinion i like the prop blast over the rudder water pick up , thaz all :p
You are so right on the boat in the bank thing. I was just remembering back when we had someone at the local pond who did hit the bank every year and would not buy a new radio. You know who you are. No names. Sorry, but was in a mood. To make up for it I will take the time to share some of my findings on pickups. Note....this is not gospel, but just what I have found from over 4 decades of constant testing. I learned a lot of things........Back in the 1980's I ran Octura rudders with the brass pickup running down the rear of the blade and sticking past the bottom of the rudder to pick up water because they were cheap, easy, and the pickup was below water level. I say below water level because I also tried pickups on the sponsons of hydros and on the transoms of mono hulls and found that pickups on the water surface likes to pick up leaves and other floating things. Not so good a thing because I burned up a few engines where the water pickup was blocked by sticks, leafs and other floating things. You would be surprised what floats! I couldn't afford the wedge rudder machined with a nice water slot that is below the water surface. So, I used the prop blast pickups and had one some of them break, which also led to engine overheating. Finally, I ended up with the slot in the rudder which Don Pinckert had been using since the beginning of model boating. Mr. Muck, and others made these rudders with the pickup in the rudder, but they were expensive and I was poor back then, so it took me a while to come over from the DARK SIDE. That's the reality side of pickups. The speed side goes like this. Not GPS, but a radar gun and official timing equipment from IMPBA substantiates these findings. In the 1980's I was at a record trial event in Maryland with a deep vee hull. The boat ran consistent passes at the same speed. The water pickup broke off the boat (was mounted to the transom) and the boat gained 3 mph. Ok..........did it run 3 mph faster because the drag was gone or the engine heated up to a better operating temperature? Never did figure it out. I ran a knife blade and a water blast two years ago at a SAW event. Gained two mph over my previous runs with a pickup in the rudder. Was it temp or drag? I went back to the rudder pickup but narrowed the width of the blade. It was thicker than the knife blade, but the boat went just as fast. I don't think the prop blast pickup is as consistent as the pickup in the rudder. Note how your roostertail is not consistent at all times. I could go on and on but the thing is.......not much difference. So.......either way.....use what flips your switch and look for speed elsewhere.
 
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