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Gear box survey

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Waterthunder

Waterthunder

Well-known member
I keep hearing people talking about Belt drive VS Rotator or Stinger gear box reliability issues. I have put hundreds of hours on them, sprayed them with over 700HP of nitrous(2 kits) and ran them on motors producing over 800HP hell I even put a clutch on one. I have yet to hurt one. I keep hearing all the belt drive sellers and owners talking about how gear boxes aren’t as reliable but the funny thing is none of them have ever owned or ran a gear box. I know ten plus years ago the first few had glitches but I also have a buddy who ones one of the very first Rotators ever made it doesn’t even have a name on it. He has Over 1,000 hours of insanely ridiculous abuse with out one problem and still runs it. So I would like to know has anybody on this board ever witness a Stinger or Rotator gear box break. Or is the bad talk the typical, I heard, he said, I know a guy ----here say!.
 
NEVER BROKE ONE NEVER SEEN ONE BROKE ... BUT HAVE SEEN SEVERAL BROKE BELTS AND SEEN BELT DRIVE UNITS BROKE
 
I have witnessed a gearbox failure firsthand it was a precision gear drive and the prop flange broke off due to improper machining the output was turned down to small and would have wrote this off to a fluke but it happened twice with less than 20 hrs. on both boxes and with catastrophic results I.E. wasted 3 blade carbon prop and destroyed cage. the guy it happened to is a freind and has sued the company that builds the box
 
Precision drives usually are pretty tough. Art malone used to run one on his blown alchohol boat. I have found them to be very noisy and if you have much cam in your motor you will get a lot of bounce back on your prop because the prop is a constant load on the gear box and the engine is not a source of constant power at idle as soon as you pick up the throttle it smooths out because of the flywheel effect. They make a lot of vibration due to this at idle. If you had one of his hubs with the rubber in it it would help some. Those drives are very old technology and were never intended for the engines we run today swingin the props we swing now. I was talkin to a guy at KISS saturday who had his boat destroyed by a sensinich prop when the bolts holding the blades in broke. They are now gonna put six bolts on the blades instead of three like they have for years.

It is always a constant challenge for the manufacturers to stay ahead of us on reliability issues. You gotta remember we are all drivin race cars in essence and with them come very little guarantees we do things with them that make engineers cringe. just stop and think about the strain on the prop and shafts when you do a 180 or a 360 spin what do you think the weight shift looks like on a chart at that point ?? it would scare you bad enough you would change the way you drive. Think about the aerobatic planes they have to build them special to take the stress and they dont even come close to doin a 180 or a 360 spin.

Maybe PRECISION needs to be sued I dont know. I do know that I would never give any kind of guarantee on a prop or a box and you would sign a waiver and a disclaimer releiving me from any responsibility for you or anyone else and property damage. Oh yeah sens. did buy the guy a new boat he said. just my thoughts on it

I also know that product liability insurance is why stuff costs so much and why many new technological innovations never reach the public. Do they install pointless ignition systems yet on small planes ??? they didnt for many years because everytime a plane crashes everyone who has touched it gets sued and the old points ignition had withstood lawsuits before so they didnt change to the better more reliable pointless type electronic ignition systems for that very reason.
 
Cntry.

The modern aerobatic planes are doing stuff that is so violent that it will snap the crank right off of a 540 with a metal prop. That is why they went to the composite props. they are pulling + and- 9+ g's too. I'll PM you a link to some videos if you like. The mags are still used both for certification reasons and because you can lose the whole electrical system and one mag and still make it home.

edit, I figured out how to link to it. Right click and "save target as".



right click here

Jim
 
i've never ran an automotive engine or reduction unit, but i know of all the seismograph crews in texas, they all run belts. they depend on their boats for their livelihood, not just a day out cruising. do they know what they're doing? i don't know but, its worth considering......
 
Yepper that was a cool video NOW JUST IMAGINE when he is comin right at you he just does a horizontal 180 or a horizontal 360 that would screw up the gyroscopic forces big time and that is what we do evry day we run.
 
You mean something like this: (same airplane, older paint job)

right click here

It's an AVI, you may need the plug in,

Jim

By the way the first video is much harder on the crank.
 
The first 180 is called a hammerhead turn. Airplanes have been doing that for probably 80 years as a turn around move in airshows or just for fun. The 540 you saw in the video is called a double hammerhead, you don't see that very often. It is a difficult move to do right. I have only seen two people do it.

Jim
 
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