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The needle bearings have more contact area when running on the shaft and these type of rpm's will kill them quick. Running on a soft shaft will chew them to. Boca ball bearings are where it's at for this stuff.
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ran needles in 20-25,000 RPM nitro engines all the time way back when,, never had one fail I believe there shape is more suited for our application as a 1/8" bearing can get cocked in the stuffing tube don't reall know in machinical terms which one is better ??Comment
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I don't think there is a way for them to Cock in the bore. I never had a problem with that. I really would advise against running the needle bearings. The flex shaft is not that hard of a material (even tho they are supposed to be hardened) that it would wear into the shaft in short order. I highly recommend the bearings you found that you posted the description on. If you want, send me your strut and I'll put them in for you (I know your fully capable of doing it tho!) But I don't mind doing it for you.
I originally bought a reamer to do these but a drill bit actually worked better. The fit is snug. Not tight. Blue loctite and then stake the last bearing in with a punch...lightly.
The bearing does not actually go in the stuffing tube. Just in the strut.32" carbon rivercat single 4s 102mph, 27” mini Rivercat 92mph, kbb34 91mph, jessej micro cat(too fast) wasComment
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32" carbon rivercat single 4s 102mph, 27” mini Rivercat 92mph, kbb34 91mph, jessej micro cat(too fast) wasComment
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Had a little time to run down to the lake and run the rivercat. It didn't go so well. I don't want you guys to think all I do is post the good, because that's not how I do things. We are all human here and we make mistakes, I'll readily admit that. Anyway, I changed the strut to a ball bearing one. Before removing the strut I checked what the original strut was when I went 97.5 mph. It had some positive angle to it. Well I didn't like that. Thought it would be better being set level. Well I thought I had 100mph in the bag. Lol. First pass....88.2mph.....huh? Somethings wrong here. I checked the batteries...yep I had 7s in it. Then noticed it had alot of water in it. A good bit....and this is ONE OF THOSE TIMES that taping it, or making it as water tight as possible won't help...the dang cooling line came off a fitting. Nice. Thought I was done for the day. Luckily I have thrown some extra cable ties in my recovery boat. Put it on, zip it tight, back in business. Next pass, pick up 1mph. I'm Suprised because I didn't think the water would hurt the speed but I guess so. I'm still not over 90 at this point. I get desperate. Break out the tools and start moving the strut. Mph is dropping. Think my lowest was 83. Now I'm getting stressed. I keep thinking that maybe that slight angle I took out...maybe that's it. The water was a little rougher than normal too. So I made about 5 or 6 passes and it just wasn't going well. Rolled it over once at low speed too. Packed up and then the wind dies completely and the water is like glass.....go figure. I decided just to head home...enough damage to my feelings was done so far lol. When I get home I do some investigating. I found a few errors on my part. One is the drive dog didn't even have 1.5mm gap from the strut...that could be a problem. Strut was level..my main culprit I think, so I put it back, prop was a touch too high out the water, fixed that. I watched the one video I did (after that depressing pass I figured it wasn't worth videoing anymore until it's straightened out again) and watched an older video to compare. I could tell it was running real wet. O well, gotta tune it back in again. Here's the pass from today and another fast pass to compare...
Today's pass.
Last edited by kfxguy; 12-15-2014, 08:12 AM.32" carbon rivercat single 4s 102mph, 27” mini Rivercat 92mph, kbb34 91mph, jessej micro cat(too fast) wasComment
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Fast pass for comparison
Fast pass.
32" carbon rivercat single 4s 102mph, 27” mini Rivercat 92mph, kbb34 91mph, jessej micro cat(too fast) wasComment
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