Strut bushing stop

[supastar1568]

hey all,

Quick question, what do y'all recommend for preventing the strut bushing from sliding backwards into the gap between the strut and the drive dog. Should the bushing be a press fit? I've heard of adding solder to the bushing in order to prevent it from slipping out. Anything else?

[Fluid]

It depends on the strut design, but on most like the SpeedMaster and its clones - do nothing! That is the way it is supposed to work. The bushing "floats" to reduce overall friction. Thousands of R/C boaters have use this method for decades, it works great. "Improving" the bushing by adding solder, glue, etc. is the wrong way to go and loses most of the advantages of the design. Just keep it lubed and it will last almost forever.


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[supastar1568]

Oh ok. Good to know. I'll leave it as is and see how it goes for me. It's my first build, and my first boat, in fact I've never see a boat run. Just building on a wim with info from this site.

I ran the boat real quick on its stand and I guess I was just surprised to see that the bushing had that much movement front to back, and that it becomes exposed between the gap of the strut and the drive dog. But yes, it's speedmaster hardware on a mean machine hull.

[Boaterguy]

The flex shaft shrinks (the windings compress) when spinning, or so I've heard, I am yet to run my first flex shaft. This space will get a little bit smaller, that is the reason for the space. It should be fine.

[planezero]

It depends on the strut design, but on most like the SpeedMaster and its clones - do nothing! That is the way it is supposed to work. The bushing "floats" to reduce overall friction. Thousands of R/C boaters have use this method for decades, it works great. "Improving" the bushing by adding solder, glue, etc. is the wrong way to go and loses most of the advantages of the design. Just keep it lubed and it will last almost forever.


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Does the same apply for the strut design of the Aquacraft UL1?
Next to the fact that the bushing is loose, the flex cable has some play inside the bushing and the bushing seems to have some play inside the strut.
Was about to replace the bushing, until I read your post, now Im not so sure :-)
The boat hasnt had many runs it...

Thanks,

[Boaterguy]

How significant is the play? if it is more than 1mm, it would be that the bushing was wrong, since they are usually sized that way, if it is almost invisible, it should be fine, the same way it should have play back and forth

[siberianhusky]

Some bushings have a slight flair on one end to keep it from sliding back.
Some stingers like the SV are the same ID as the OD of the Octura led/teflon bushings, two of them are needed and have less drag by feel than a full length brass bushing.

[planezero]

By the bushing, the flex cable has about 0.5 mm of play.
Behind the prop I mounted one of those silly bullet-nuts, and at the end of that (bushing to end of nut is 4.0 cm) the play measures to 2 mm, enough to see the prop move quiet drastically.
Just doesnt seem right that I go to all that effort to balance the prop etc...only to have so much play in the flex cable...
I'll order a new one from Steven to see if it improves with a new bushing.

[supastar1568]

This is what I was referring to in my original post:

[siberianhusky]

That looks a lot like the strut on my hydro, but it has a ball bearing on the back end the 3/16 solid part of the shaft rides in. When you look at the back of that strut is there a larger diameter hole at the very end than steps down inside the strut? About 1/8" in or so? If so maybe it should have the same bearing set up mine came with?

[Steven Vaccaro]

This is what I was referring to in my original post:

Thats a bit more space than I normally keep between the dog and strut. But your bushing should still be riding/spinning within the stuffing tube. If thats the case, like Jay said, you are fine.

[supastar1568]

That looks a lot like the strut on my hydro, but it has a ball bearing on the back end the 3/16 solid part of the shaft rides in. When you look at the back of that strut is there a larger diameter hole at the very end than steps down inside the strut? About 1/8" in or so? If so maybe it should have the same bearing set up mine came with?

No, there is no counter bore in the rear of the strut.

Steven, the bushing spins freely inside of the strut. The stuffing tube ends where the strut begins. In other words, the stuffing tube does not go into the strut. The joint is sealed with the heat shrink tubing.

[planezero]

I took the (original) strut bushing out of my SV27 and put it in my UL1 ...
Et viola! no more play, all gone...
The SV27 strut is at least 5 mm longer (5 holes at the side) than the (original) one from my UL-1 (4 holes).
Strange because its the same spare part...
The UL1 strut measures 38mm.
Any1 else have this ??

@Steven, how long is the AQUB7884 original part?

Regards,
Berry