Drive line vibration

[WikiWiki1]

Hi, I am setting up my first 1/8 scale boat. I'm not happy with the harmonic vibration that occurs

when running on the stand. My question is how much vibration should there be? at low to mid rpm it seems pretty smooth, but when it spins up to high rpm the prop becomes a blur and it buzzes pretty good.I have a 1/4 square flex cable and a 3/16 stub shaft. The stuffing box has an S bend and uses a teflon liner. It's 1/4 inch from the motor collet and 1/4 inch from the ferrule. The ferrule appears to be on straight. I have read some threads on here about soldering on the ferrule and have tried to follow along but it's trickier than it seems. Any suggestions would be great.

Thanks, Brent

 

[Mark Bullard]

Hi, I am setting up my first 1/8 scale boat. I'm not happy with the harmonic vibration that occurs

when running on the stand. My question is how much vibration should there be? at low to mid rpm it seems pretty smooth, but when it spins up to high rpm the prop becomes a blur and it buzzes pretty good.I have a 1/4 square flex cable and a 3/16 stub shaft. The stuffing box has an S bend and uses a teflon liner. It's 1/4 inch from the motor collet and 1/4 inch from the ferrule. The ferrule appears to be on straight. I have read some threads on here about soldering on the ferrule and have tried to follow along but it's trickier than it seems. Any suggestions would be great.

Thanks, Brent

Well I may be fixing to get beat up on this but here goes. I have not used a teflon liner or a ferrule shaft in over twenty years. They sort of went to the way side along with hard shafts. When the flex shafts that we run today came around it end that era. The gas guys sort of brought this back and I do not know for what reason. Is the tube running thru the hull a 11/32" brass tube? If is is your home free just remove the liner and the strut. Now drill out strut to 5/16". Insert a 5/16" brass tube into the strut and then insert the 5/16" tube into the 11/32" brass tube alway to the motor stopping about 3/8" from the motor. Bent the tube where it leaves the hull so that it will be the right angle for the strut. Now with the strut in place cut the 5/16" tube flush with the rear of the strut. Now buy a 1/4" x 3/16" shaft and shaft bushing from Bill McGraw at SpeedMaster Products or anyone else that sells boating supplies. mount your drive dog insert the shaft into the strut and then measure the amount that need to be cut out the shaft. You will neet about 1/4" of distance from the drive dog to the strut. Balance the prop grease the shaft with a good bearing grease and run the boat. The grease will run for about 5 rounds after you get a good build up grease in the tube and in the shaft but on a new shaft you need to grease it about every two rounds.

 

[WikiWiki1]

Thanks for the info Mark. I have a local boater that's going to help me solder up a new shaft properly. I'll give it a try before I change to another setup. I do have one question about the flex shaft setup. How do you keep the whole works from backing out of the tube and sinking to the bottom. is there some sort of retainer or does the collet hold it in?

Brent

 

[shoboat]

Brent,

Mark gave you solid advice, that is way to go. Now if you need any "Speed Lube" we will have it

here for sale in a few days.

Good Luck Testing,

Mark Sholund

 

[Mark Bullard]

Thanks for the info Mark. I have a local boater that's going to help me solder up a new shaft properly. I'll give it a try before I change to another setup. I do have one question about the flex shaft setup. How do you keep the whole works from backing out of the tube and sinking to the bottom. is there some sort of retainer or does the collet hold it in?

Brent

The collet holds it in place. Now yes you will lose a prop every now and then but it will be due to shaft breakage and no more that shaft breakage in what you are going to run.

Now the important thing to remember when setting up any flex shaft is to not solder the end of the shaft that goes into the collet. Early on when I first started using flex shafts we thought that we need to do that. After the first couple of years of breaking shafts about every couple of races I decided to go into the shaft bussiness. I did for awhile and one day when I was welding the stub on a cable it sort of hit me. If the cable is welded in the stub and when you solder the end that goes into the motor collet and then put the bends in the shaft log tube, what do you have? You have a flex that is trying to be a straight shaft. The different wires in the shaft cannot move so the shaft will break. I have shafts that are over 20 years old and still work just fine. Ask around and find out how many shafts that a racer has laying around that has been solder on the end that goes into the collet. I bet you will find that he does not have many.

Mark

 

[missbudpilot55]

Thanks for the info Mark. I have a local boater that's going to help me solder up a new shaft properly. I'll give it a try before I change to another setup. I do have one question about the flex shaft setup. How do you keep the whole works from backing out of the tube and sinking to the bottom. is there some sort of retainer or does the collet hold it in?

Brent

The collet holds it in place. Now yes you will lose a prop every now and then but it will be due to shaft breakage and no more that shaft breakage in what you are going to run.

Now the important thing to remember when setting up any flex shaft is to not solder the end of the shaft that goes into the collet. Early on when I first started using flex shafts we thought that we need to do that. After the first couple of years of breaking shafts about every couple of races I decided to go into the shaft bussiness. I did for awhile and one day when I was welding the stub on a cable it sort of hit me. If the cable is welded in the stub and when you solder the end that goes into the motor collet and then put the bends in the shaft log tube, what do you have? You have a flex that is trying to be a straight shaft. The different wires in the shaft cannot move so the shaft will break. I have shafts that are over 20 years old and still work just fine. Ask around and find out how many shafts that a racer has laying around that has been solder on the end that goes into the collet. I bet you will find that he does not have many.

Mark

After you loose a couple of those one off or expensive props you figure that one out in a hurry. But it is a very good point that Mark is making here, it is a classic mistake a lot of beginners make when they start out.

One that hasn't been mentioned in a long time and us older guys seem to forget to pass on to the rookies.

That's why this board ROCKS.................

 

[Mark Bullard]

Thanks for the info Mark. I have a local boater that's going to help me solder up a new shaft properly. I'll give it a try before I change to another setup. I do have one question about the flex shaft setup. How do you keep the whole works from backing out of the tube and sinking to the bottom. is there some sort of retainer or does the collet hold it in?

Brent

The collet holds it in place. Now yes you will lose a prop every now and then but it will be due to shaft breakage and no more that shaft breakage in what you are going to run.

Now the important thing to remember when setting up any flex shaft is to not solder the end of the shaft that goes into the collet. Early on when I first started using flex shafts we thought that we need to do that. After the first couple of years of breaking shafts about every couple of races I decided to go into the shaft bussiness. I did for awhile and one day when I was welding the stub on a cable it sort of hit me. If the cable is welded in the stub and when you solder the end that goes into the motor collet and then put the bends in the shaft log tube, what do you have? You have a flex that is trying to be a straight shaft. The different wires in the shaft cannot move so the shaft will break. I have shafts that are over 20 years old and still work just fine. Ask around and find out how many shafts that a racer has laying around that has been solder on the end that goes into the collet. I bet you will find that he does not have many.

Mark

After you loose a couple of those one off or expensive props you figure that one out in a hurry. But it is a very good point that Mark is making here, it is a classic mistake a lot of beginners make when they start out.

One that hasn't been mentioned in a long time and us older guys seem to forget to pass on to the rookies.

That's why this board ROCKS.................

Thanks Bill.

My tent is always open for anyone that need a little help with something. I have help a lot of racers that have came over to my tent and ask over the years. And Bill you are very right that sometimes us older racers forget to pass it on to the rookies. But there again I am not going to go into a persons pit and tell him he is doing it wrong. The main thing is all he has to do is walk into my pit and ask and I will tell him any thing he wants to know.

Mark

 

[missbudpilot55]

Thanks Bill.

My tent is always open for anyone that need a little help with something. I have help a lot of racers that have came over to my tent and ask over the years. And Bill you are very right that sometimes us older racers forget to pass it on to the rookies. But there again I am not going to go into a persons pit and tell him he is doing it wrong. The main thing is all he has to do is walk into my pit and ask and I will tell him any thing he wants to know.

Mark

Right on Mark, if you were looking over everyones shoulder you wouldn't have time for "Racin"

 

[david cox]

Hi Mark:

Are you saying that the end of the flexshaft will not "unravel" if you don't solder the end that goes in the collet? I have never tried your method but it does sounds interesting. I find that the solder will sometimes get caught in the collet and this will prevent the collet from tightening properly, and will cause the flexshaft to slip, or even worse fall out the back of the boat. I am just concerned that the flexshaft will unravel if not soldered at the collet.

Thanks, David

 

[Mark Bullard]

Hi Mark:

Are you saying that the end of the flexshaft will not "unravel" if you don't solder the end that goes in the collet? I have never tried your method but it does sounds interesting. I find that the solder will sometimes get caught in the collet and this will prevent the collet from tightening properly, and will cause the flexshaft to slip, or even worse fall out the back of the boat. I am just concerned that the flexshaft will unravel if not soldered at the collet.

Thanks, David

No it will not unravel. The collet will compress the conductors on the cable and will hold very well. I have never had a shaft slip or unravel this way. Now I have had the inter-core try to come out of the shaft and this is where the cable is not welded good at the stubshaft. I will pull those shafts and send them back to who every I get them from and there is never any question asked.

Mark

 

[Josh Stollfuss]

I set up the drive line in my sport 40 in the method described without the teflon tube liner. I added a flex shaft oiler and the whole system seems to be bullet proof! I was really pleased this weekend when I ranthe boat for the 1st time, thanks to all for the advice!

Josh-

 

[[email protected]]

I never use the teflon liner, I go just enough clearence for the flex cable and keep it will lubed w/my own personel lended lube. And since I've gone away from teflon I no longer wrap cables into knots!

As for losing a flex cable, I've used a small o-collars so if it backs out it simply can't get through the brass shaft. I've never had any problems with balance or wrecking bearings or speed. Plus I don't lose $50 to $60 props. I might get beat up over that because I've heard pro's/con's about doing it.

 

[dannyual767]

Rodney, can you describe and explain how you use the O-collars that you mentioned? Maybe a picture? These props are too expensive and/or time consuming to lose !