Proper Use of Sleeve Bushings

[properchopper]

Thanks. I guess what I am really concerned about now is the fact that the flange on the bushing can come completely out of the strut which eliminates the centering feature.

The boat I have where the bushing slides out to meet the drive dog doesn't have a flanged bushing, the "bushing" actually runs inside the strut stuffing tube all the way up to the coupler - crazy setup but it was that way when the boat came to me used. If and when this wears out, rather than replace the whole "bushing/tube, I'll go wire drive. My UL-1 has that flanged bushing , does slide out some but not past the end of the flange, which I agree can't be good.

Where did you get the ball bearing strut? Thanks.

Jeff Wohlt at rcraceboat.com

[Jeff Wohlt]

I make them.

http://www.geocities.com/jwohlt5362/Storestrut.html

I will begin offering ceramic bearings but cost will be up slightly. Maybe an option for the bearings.

I should note. Noses are also availble for 150 cables and 1/4" nose for the 1/4" factry stuffing tube. Most rip out the teflon and can go to a smaller KS stuffing tube.

The stuffing tube does not go all the way thru but just about 1/4" in the nose. Octura shafts works the best in these...perfect fit.

[longballlumber]

Thanks. I guess what I am really concerned about now is the fact that the flange on the bushing can come completely out of the strut which eliminates the centering feature. I think I just need to head up to the hobby shop and take a look at a new one. I'm not even sure if the flange should be into the strut or not. Anyways, when the flange slips out, the bushing is cocked slightly in the strut. This can't be any good?? huh??

Where did you get the ball bearing strut? Thanks.

Shooter,

I have ran my UL-1 with the strut bushing as is for HOURS AND HOURS without any problems. This is a solid design, that has been used for years. The "floating" action of the bushing is fine.

Mike

[tiqueman]

Interesting topic. Hmm, well, Im not going to say what I think is right or wrong. Because I dont have enough experience with FE to have an answer.. or an opinion for that matter. I come from a gas boat background, for pleasure, never raced them, no records, titles or anything like that. Just a man who loves boats. All my gassers have the pressed in lead bushings and I do replace them often as they do develop slop. I grease and lube the drive hrdwr at every run to delay the wear process, but my parts box will tell you, I do replace them.

As for my FEs, Im glad to see some folks with my same question about the strut bearing sliding back to the drive dog. I put a new strut on my cat. I used the Aquacraft Miss Vegas strut. I installed a 1/4" stuffing tube that goes into and through the strut until about 3/16 to the back end of it. I made my own strut bushing, using a piece of 7/32 brass, I drilled 5 sets of holes (10 holes) through it and soldered a piece of the 1/4 inch, cut at about 1/8 inch long, at the end of it to keep it from traveling into the stuffing tube. Im running Octura .150 on a 3/16 shaft. It wanders around, but as long as it makes it around the pond and back to me, it works for me And if I have to replace it next week or in 2 years, one piece of each tube that I already purchased and 15 minutes of fabricating and that strut is set for a looong time, as I can make several bushings.
In the pic, you can see that the strut bushing is against the drive dog. It is still plenty in the 1/4" stuffing tube as well. Ive only got less than 10 runs on it so far, and Im not seeing any wierd markings or scoring or anything on it yet. So Im guessing this is okay. AND, the only way I can think of to fix this, if it is a problem, would be to solder it to the stuffing tube so it couldnt move. But like I said, I dont see it as a problem and Ive never heard of anyone doing that.

[Fluid]

I started this thread just to inform members how this old and successful design is supposed to be used. Some folks seem to think this is some new and untested design, or that they somehow know better than hundreds of successful fuel boaters and race boat designers....

Guys, regardless of your personal theories the bushing is supposed to float back and forth on the stub shaft - and it works great on boats running 35 mph or 125 mph. Wear is not an issue if adequate lube is used, the sleeve bushing lasts longer than lead/teflon bushings, plus it is cheap and easy to replace (if you ever need to do so). Use it or not, whine about it or not - nothing changes the fact that it is a completely proven and successful technology when applied correctly.




.

[ED66677]

Jay,
this is a very interresting thread, as mechanic engineer, I can only agree with your statement, not having half of your boater experience though, the mechanic rules apply and that's it!
I made my own strut for my 29" copy, using two fixed brass bushings (successfully but not intensively), I will soon modify it for a single longer one, the fact that RPM's are "splitted" between 3 parts (strut/bushing/shaft) instead of 2 can only be good!

[ozzie-crawl]

only thing i would like to know is i always here your suppose to keep a gap between dog and strut the same size as the shaft wich is 3/16 (4mm) but the flange that centres the bushing is only 3mm, only way to stop it coming out is to keep it at around 2.5mm gap

[Simon.O.]

Scott, I can see what you mean...I think.
The floating bush can be setup so that it will not slide out the front of the strut. This can be by a neck on the bush or a shoulder at the front of the strut to retain the bush. I use my own system as my whole strut-stub assembly is my design.

The bush should spin. That is clear.
It should slide in from the rear and then the stub is set for the gap that you normally use. I use very little gap on my wire drives and the rear of the bush is just inside the strut so the dog can push forward onto the rear of the strut, if it goes that far forward.

I am sure that is now as clear as mud.

ED You have the idea right. The rotational speed is shared. Once you are down to low diameter shafts like I use (1/8"and 5/32") then the rotating surface area is reduced and it all gets better.

[Shooter]

Excellent discussion.

Ozzie - My problem exactly. The stock flange isn't quite long enough to allow the proper gap between the dog and strut. If the bushing flange slips out on the prop side, the bushing is cocked in the strut bore.

[ED66677]

Shooter,
Excuse me if I ask a dumb question but what does the flange have to do with the gap??? if the flange of the bushing is outside of the strut body, then the gap has to be set between the bushing's flange and the prop, if the flange is inside the strut then the gap has to be set between strut and prop.
That said, is your bushing just a short piece 1/4" long on each end of the strut or is it 2" long or so?

[Jeff Wohlt]

The only thing I will add is this is just one set up style you are seeing on some boats....started with nitro/gassers. It works and that is simple enough. Nothing real hard about how or why they do it this way.

Although...almost EVERY FE set up run for years ran Fuller/fine or Octura struts and teflon. The SV and UL1 and Vegas were the first I had ever seen from the factory this way and it was simply carried over from their nitro versions....why re-invent the wheel when it all fits easy enough for the FE versions.

I simply use one of these that slides in the strut and can be used for any of the struts on SV/vegas or any of those but not using the stuffing tube all the way thru the strut.

They begin life as 1/4" KS and then end up with 3/16" ID with slots.

I guess why not get rid of the teflon from these factories? Just makes the tube larger under the hull for drag.

[longballlumber]

I guess why not get rid of the teflon from these factories? Just makes the tube larger under the hull for drag.

I my short career in FE racing, I have yet to see the difference in stuffing tube OD's (between wire and flex) make a difference in speed. Otherwise all of the "fast guys" would be using which ever is faster.

Both systems have been sucessfully used and proven. For the discussion of this particular thead my input is; it's not broken so don't fix it.

Mike

[ED66677]

agree with you Mike, but if I can save few watts, she'll go faster, that's all we want isn't it?

[longballlumber]

I can save few watts, she'll go faster, that's all we want isn't it?

I agree 100%... but, again, I have yet to be convinced that wire drive lines, lead bushing struts, ball bearing struts, brass bushed struts, wire, flex cables, stuffing tube OD's and etc...

I don't think one is better than the other. All that are properly set up will be fast.

Mike

[Jeff Wohlt]

For wire 5/32 stuffing tube for 078. 1/8" for 062. Pretty small....easier to bend for setting up.

But for cables you certainly are able to step down a size or two when removing the teflon.

Try a true bearing strut and you will never go back to any of the set ups above anyway.

No, it is about resistance...everything we do for these is about that.