rudder notch for proper water cooling

[Terry Keeley]

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.

Thanks for sharing John, this is what I think too. Made some 0.075" thick blades from 7075 (0.040" hole) but they they didn't hold up (bent), gonna try using Ti next.

 

[Gerald Carijuton]

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 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

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.

Thanks John , you would know best , you have brought alot to this hobby , i remmeber reading your articales in the boat mags and i still have them put away , you are a legend and i wasen't trying to disrespect you in any way , i just like to share what has worked for me in the past.

 

[John Finch]

Thanks Gerald. You are top notch!

 

[Charles Perdue]

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.

Thanks for sharing John, this is what I think too. Made some 0.075" thick blades from 7075 (0.040" hole) but they they didn't hold up (bent), gonna try using Ti next.

Hello Terry, the Ti is VERY difficult to work with when using the small bits neccessary for the pickup.

I use a butcher knife blade (Old Hickory is a good one). I carefully shape the blade, makeing sure to keep it cool enough that it does not change color. I use a dremel and a cutoff disc to slot the rear of the blade about 1/8 deep. On the very bottom of the blade where the pickup hole is going, I anneal that area and drill the pickup hole starting from the rear, using a piece of aluminum for a backup to keep the drill from breaking when it comes out the side of the blade. I then make a water fitting with a slot in the bottom to sit down over the top of the blade at the rear. I then slide a peice of Ti wire (it is used in making cheap jewelry) in the slot and solder over it. Then remove the wire, the solder will not stick to it. I am sure there are other ways of making a thin blade with a water pickup but this is the easiest way that I have found. Weight is not much of an issue with the thin blade. If you need some Ti wire I can send you some.

Charles

 

[Terry Keeley]

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.

Thanks for sharing John, this is what I think too. Made some 0.075" thick blades from 7075 (0.040" hole) but they they didn't hold up (bent), gonna try using Ti next.

Hello Terry, the Ti is VERY difficult to work with when using the small bits neccessary for the pickup.

I use a butcher knife blade (Old Hickory is a good one). I carefully shape the blade, makeing sure to keep it cool enough that it does not change color. I use a dremel and a cutoff disc to slot the rear of the blade about 1/8 deep. On the very bottom of the blade where the pickup hole is going, I anneal that area and drill the pickup hole starting from the rear, using a piece of aluminum for a backup to keep the drill from breaking when it comes out the side of the blade. I then make a water fitting with a slot in the bottom to sit down over the top of the blade at the rear. I then slide a peice of Ti wire (it is used in making cheap jewelry) in the slot and solder over it. Then remove the wire, the solder will not stick to it. I am sure there are other ways of making a thin blade with a water pickup but this is the easiest way that I have found. Weight is not much of an issue with the thin blade. If you need some Ti wire I can send you some.

Charles

Sounds like a good way to go too, might have a closer look at that after I break a few carbide drills... :unsure:

Thanks for the offer, got a nice piece on fleeBay a while back.

Any tips for drilling 6Al4V? I'm reading that carbide works best with a split point drill. Cut it like stainless or it work hardens.

 

[Charles Perdue]

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.

Thanks for sharing John, this is what I think too. Made some 0.075" thick blades from 7075 (0.040" hole) but they they didn't hold up (bent), gonna try using Ti next.

Hello Terry, the Ti is VERY difficult to work with when using the small bits neccessary for the pickup.

I use a butcher knife blade (Old Hickory is a good one). I carefully shape the blade, makeing sure to keep it cool enough that it does not change color. I use a dremel and a cutoff disc to slot the rear of the blade about 1/8 deep. On the very bottom of the blade where the pickup hole is going, I anneal that area and drill the pickup hole starting from the rear, using a piece of aluminum for a backup to keep the drill from breaking when it comes out the side of the blade. I then make a water fitting with a slot in the bottom to sit down over the top of the blade at the rear. I then slide a peice of Ti wire (it is used in making cheap jewelry) in the slot and solder over it. Then remove the wire, the solder will not stick to it. I am sure there are other ways of making a thin blade with a water pickup but this is the easiest way that I have found. Weight is not much of an issue with the thin blade. If you need some Ti wire I can send you some.

Charles

Sounds like a good way to go too, might have a closer look at that after I break a few carbide drills... :unsure:

Thanks for the offer, got a nice piece on fleeBay a while back.

Any tips for drilling 6Al4V? I'm reading that carbide works best with a split point drill. Cut it like stainless or it work hardens.

The carbide split point drill is good for Ti. Plenty of lube. It work hardens much quicker than stainless.

Mr. Jim Allen could help you a lot more on working with the Ti than I can.

 

[Jim Allen]

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.

Thanks for sharing John, this is what I think too. Made some 0.075" thick blades from 7075 (0.040" hole) but they they didn't hold up (bent), gonna try using Ti next.

Hello Terry, the Ti is VERY difficult to work with when using the small bits neccessary for the pickup.

I use a butcher knife blade (Old Hickory is a good one). I carefully shape the blade, makeing sure to keep it cool enough that it does not change color. I use a dremel and a cutoff disc to slot the rear of the blade about 1/8 deep. On the very bottom of the blade where the pickup hole is going, I anneal that area and drill the pickup hole starting from the rear, using a piece of aluminum for a backup to keep the drill from breaking when it comes out the side of the blade. I then make a water fitting with a slot in the bottom to sit down over the top of the blade at the rear. I then slide a peice of Ti wire (it is used in making cheap jewelry) in the slot and solder over it. Then remove the wire, the solder will not stick to it. I am sure there are other ways of making a thin blade with a water pickup but this is the easiest way that I have found. Weight is not much of an issue with the thin blade. If you need some Ti wire I can send you some.

Charles

Sounds like a good way to go too, might have a closer look at that after I break a few carbide drills... :unsure:

Thanks for the offer, got a nice piece on fleeBay a while back.

Any tips for drilling 6Al4V? I'm reading that carbide works best with a split point drill. Cut it like stainless or it work hardens.

The carbide split point drill is good for Ti. Plenty of lube. It work hardens much quicker than stainless.

Mr. Jim Allen could help you a lot more on working with the Ti than I can.

Mr Charles Perdue has the right ideas for drilling Titanium alloys. Even though different grades require different machining techniques, all the grades are similar in that they have very low thermal conductivities & therefore do not dissipate any heat generated through the piece being machined or drilled. I prefer a faceted ground drill point with four facets rather than a split point drill. The faceted drill point has a much higher strength than the split point drill at the cutting point. It also cuts from the center. It can be re-sharpened by hand with some pratice after one recognizes how the point geometry is generated. Of course, only diamond abrasives should be used to sharpen carbide.

Continous maxium pressure must be maintained while the drill is cutting; frequent removal of chips is necessary; Large amounts of chlorinated sulfur based type oils need to be added to the cutting area; use only enough drill length to cut to a certain depth, lengthening the drill in steps to go deeper; "peck drilling" is the proper technique to use; stop drilling immediately when the drill stops cutting; use lower cutting speeds with higher feeds; rigidity between the work piece & the drill are essential; sometimes aluminum heat sinks can be used when drilling thin pieces.

Jim Allen

 

[Terry Keeley]

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.

Thanks for sharing John, this is what I think too. Made some 0.075" thick blades from 7075 (0.040" hole) but they they didn't hold up (bent), gonna try using Ti next.

Hello Terry, the Ti is VERY difficult to work with when using the small bits neccessary for the pickup.

I use a butcher knife blade (Old Hickory is a good one). I carefully shape the blade, makeing sure to keep it cool enough that it does not change color. I use a dremel and a cutoff disc to slot the rear of the blade about 1/8 deep. On the very bottom of the blade where the pickup hole is going, I anneal that area and drill the pickup hole starting from the rear, using a piece of aluminum for a backup to keep the drill from breaking when it comes out the side of the blade. I then make a water fitting with a slot in the bottom to sit down over the top of the blade at the rear. I then slide a peice of Ti wire (it is used in making cheap jewelry) in the slot and solder over it. Then remove the wire, the solder will not stick to it. I am sure there are other ways of making a thin blade with a water pickup but this is the easiest way that I have found. Weight is not much of an issue with the thin blade. If you need some Ti wire I can send you some.

Charles

Sounds like a good way to go too, might have a closer look at that after I break a few carbide drills... :unsure:

Thanks for the offer, got a nice piece on fleeBay a while back.

Any tips for drilling 6Al4V? I'm reading that carbide works best with a split point drill. Cut it like stainless or it work hardens.

The carbide split point drill is good for Ti. Plenty of lube. It work hardens much quicker than stainless.

Mr. Jim Allen could help you a lot more on working with the Ti than I can.

Mr Charles Perdue has the right ideas for drilling Titanium alloys. Even though different grades require different machining techniques, all the grades are similar in that they have very low thermal conductivities & therefore do not dissipate any heat generated through the piece being machined or drilled. I prefer a faceted ground drill point with four facets rather than a split point drill. The faceted drill point has a much higher strength than the split point drill at the cutting point. It also cuts from the center. It can be re-sharpened by hand with some pratice after one recognizes how the point geometry is generated. Of course, only diamond abrasives should be used to sharpen carbide.

Continous maxium pressure must be maintained while the drill is cutting; frequent removal of chips is necessary; Large amounts of chlorinated sulfur based type oils need to be added to the cutting area; use only enough drill length to cut to a certain depth, lengthening the drill in steps to go deeper; "peck drilling" is the proper technique to use; stop drilling immediately when the drill stops cutting; use lower cutting speeds with higher feeds; rigidity between the work piece & the drill are essential; sometimes aluminum heat sinks can be used when drilling thin pieces.

Jim Allen

Wow, thanks guys, what a wealth of information here!

I'll have to look into that "faceted" ground point Jim. I just picked up a Baldor 522 carbide grinder with 2 diamond wheels and a Black Diamond drill sharpener, both in great shape.

Not sure if the BD can do that point tho... :unsure: