Help! Yes, my prop is dynamically unbalanced and blindly sanding at guessed at locations has helped somewhat. I now know I need a $1500 Dynavibe balancer, which is a quarter what I paid for N81JM. Can these be rented? Does anyone in Northern California have one? Any suggestions?
On Thu, May 26, 2022, 5:40 PM MS <[email protected]> wrote: > I'll second the importance of keeping the prop dynamically balanced. > > A Dynavibe balancer, the one they call the "Classic" (rather than the > higher priced model the name of I've forgotten, other than they want 4K for > it) should be conidered an essential hangar tool. Mark has one and I've > got both the classic and the X3 or whatever they call it. I've got both of > them - the company just sent me the fancy one when it first came out. When > I asked "why" they just said they'd appreciate an evaluation. In view of > such generosity I didn't really give them an evaluation of the X3 since, to > me, it's a complete waste of money. It will accept two cables providing > info from two sensors, one in front and the other at the rear of the engine > thus helping to diagnose some internal problem. You still have to take the > engine apart to see what the issue is, so what good is a vibration > diagnosis? At any rate, the features of the X3 may be of use to full-time > engine professionals. For keeping a smooth prop that does just as good a > job as its expensive brother, the $1500 Classic model is excellent. I > found the X3 unusable actually. Supposedly it tells you exactly how much > weight to use when balancing, but this is something you get a "feel" for > after using the cheap one for any period of time. You still have to run > the engine up one more time to check the accuracy of the weight placement, > whichever one you're using, so the X3 turned out to just be a PITA. I > should have sold it long ago. It's just another thing I've let pile up > that needs doing. > > Anyway, a dynamically balanced prop is a joy to operate. You'll get more > RPM's for the same throttle/mixture setting. Instruments and control > attachments will be less stressed, as will the pilot and passengers and the > engine bearings. There's nothing like doing your balancing yourself. > Take it to a shop and you can bet they won't do as fine a balance as you > will. I've done a few balance jobs that had been recently balanced by a > "shop" and in some (most) cases their margins were ridiculous compared to > how perfectly you can do it using your own balance job. Since the intro of > the Dynavibe back in 2006 or 7, one or two other companies have come out > with low cost balancers so they're not hard to find. I can't imagine > they'll be any better than the Dynavibe however. I've done dozens and > dozens of balance jobs since I got mine in 2007 and I've never needed any > maintenance with the sensors or the hand-held computer. Mount it on a > pedestal shop fan for practice and to learn how it works and save a bunch > of avgas. > > The "C" model Comanche and the Twin Comanches after a certain year had > extensions and didn't have problems . . . but then they had Lycomings, not > Revmasters. The cranks may be just as good on both, for all I know. They > have to be forged of course. Cast cranks (and flywheels, etc.) were the > death of HAPI. > > Mike > KSEE > > > > > -- > KRnet mailing list > [email protected] > https://list.krnet.org/mailman/listinfo/krnet >
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