BalanceMaster testing

[spacesailor]

Smokeybear.

 

I only need that prop for the monthly engine runs, No license (certification) so it';s not going anywhere but making noise.

 

The engine I acquired had a "rich" cylinder. that I saw on "visual" had its rubber cap (on the side of the carbi" missing. . A bit of tube & a 22 shed-case plugged. that problem, then tuned it up, to exceed the recommended tacho speed.

 

spacesailor

 

 

[Old Koreelah]

I fitted my Balance Master a couple of weeks ago.

 

After lots of stuffing about trying to fit it in front of the prop, I gave up and just mounted it behind, between the drive hub and my spinner's back plate. Although the BM looks flat on one side, the mercury-filled tube protrudes about one mm, so bolting that "flat" face up against my spinner plate distorts it slightly.

 

Lacking instruments to measure any difference in vibration, I can only report that it seems noticeably smoother when idling, so much so that it can now tick over down to 600 rpm, something it's never done before.

 

 

[rhtrudder]

On 15/6/2018 at 9:52 PM, smokeybear said:

I have been bringing in the Balancers for some years, they do a fantastic job and I believe extend the life of the gearbox & engine as well the reduced vibration throughout the airframe reducing  fatigue.

 

I have Balancers on hand for

 

Rotax 912/914 

 

Rotax 503 flywheel 

 

Rotax 582 & Lycoming on order.

 

 

Hi are you still bringing in the balancers 

[skippydiesel]

Has the "Balance Master" (BM), been empirically proven to be effective?

 

I purchased & fitted one to my last aircraft -made no apparent difference, in vibration. NOTE: My prop had been carefully static & dynamically balanced.

 

I rationalised the expense, as a just in case/safety feature. Just in case, I lost a chunk out of my prop, the  BM might minimise the resultant vibration, to allow a safe landing. I have no idea if the BM would be effective in this scenario. 😈

[facthunter]

It can mask things you should take notice of. nev

[Moneybox]

8 hours ago, skippydiesel said:

Has the "Balance Master" (BM), been empirically proven to be effective?

 

I purchased & fitted one to my last aircraft -made no apparent difference, in vibration. NOTE: My prop had been carefully static & dynamically balanced.

 

I rationalised the expense, as a just in case/safety feature. Just in case, I lost a chunk out of my prop, the  BM might minimise the resultant vibration, to allow a safe landing. I have no idea if the BM would be effective in this scenario. 😈

 

In the tests I've watched it seemed to make a noticeable difference at very low revs.

[facthunter]

That's odd. At low revs the forces are low.( V squared law.). There's not much flywheel effect in light components. Perhaps the extra weight helps there.. I'm for balancing the sections by themselves not the entire show. THAT way you know nothing's far off. I've been doing balancing for ages, professionally. The  vibrations you don't feel are the TORSIONAL ones and they can be destructive  especially with longer thinner crankshafts and places where you have something  ACTING like a flywheel at each end. Any vibration that wasn't there before should be regarded as a warning and in many planes with vibration measuring devices would require an in flight shut down.  Nev

[Moneybox]

A couple of testers quoted vibration free idle at 600 rpm on a Rotax 912ULS.  That's 1/2 to 1/3 of the recommended rpm.

[facthunter]

 Yes I wouldn't GO there. You are running through reduction gears and a cam face thing. It must be getting a work out . IF you've ever heard an engine running with a slightly loose flywheel, you will get the idea. Nev

[skippydiesel]

41 minutes ago, Moneybox said:

A couple of testers quoted vibration free idle at 600 rpm on a Rotax 912ULS.  That's 1/2 to 1/3 of the recommended rpm.

Hmm!

 

What equipment did they use to back up, what I assume is, their very flawed/limited,  human perception?

 

I stand to be corrected; Rotax 912ULS should not be idled for any length of time below 2000 rpm, except during shut down when, depending on technique, minimum idle is 1400 - 1700 rpm😈

[Area-51]

I use balance master for three years now; its great; mounted behind bolly prop hub.... carbis all balanced 912 purrs very smooth at 600rpm no gearbox rattles; very quiet, no vibration..

 

because prop shaft is divorced from crankshaft a second balance master mounted at rear of prop shaft will deal with residual imbalance of prop shaft. Nobody gives the rear of the prop shaft any attention 👨‍✈️✈️

[Red]

10 minutes ago, Area-51 said:

I use balance master for three years now; its great; mounted behind bolly prop hub.... carbis all balanced 912 purrs very smooth at 600rpm no gearbox rattles; very quiet, no vibration..

 

because prop shaft is divorced from crankshaft a second balance master mounted at rear of prop shaft will deal with residual imbalance of prop shaft. Nobody gives the rear of the prop shaft any attention 👨‍✈️✈️

the rear of the prop shaft on a 912 simply inserts into a bearing in the gearbox casing, there is no way to mount a balance master there, do you mean behind the prop hub?

[Red]

38 minutes ago, skippydiesel said:

Hmm!

 

What equipment did they use to back up, what I assume is, their very flawed/limited,  human perception?

 

I stand to be corrected; Rotax 912ULS should not be idled for any length of time below 2000 rpm, except during shut down when, depending on technique, minimum idle is 1400 - 1700 rpm😈

Yes and the reason it causes wear and damage is the power pulses so no amount of balancing will alleviate this it might reduce vibration but you still shouldnt idle down anywhere near those RPMs (600 RPM)

Edited Tuesday at 08:58 AM by Red

[skippydiesel]

18 minutes ago, Area-51 said:

I use balance master for three years now; its great; mounted behind bolly prop hub.... carbis all balanced 912 purrs very smooth at 600rpm no gearbox rattles; very quiet, no vibration..

 

because prop shaft is divorced from crankshaft a second balance master mounted at rear of prop shaft will deal with residual imbalance of prop shaft. Nobody gives the rear of the prop shaft any attention 👨‍✈️✈️

I am intrigued - what empirical tests have you done, to back up what reads as human perception?

 

Dont get me wrong - I love the idea , I just want proof it actually works. Without proof, it becomes faith, which I have little time for😈

Edited Tuesday at 09:02 AM by skippydiesel

[Blueadventures]

1 hour ago, Moneybox said:

A couple of testers quoted vibration free idle at 600 rpm on a Rotax 912ULS.  That's 1/2 to 1/3 of the recommended rpm.

Some testers are considering the gear ratio not engine rpm on tacho; therefore 600 rpm of prop may be about 1500 rpm on a Rotax 912.

[Red]

Perhaps moneybox could inform on where he read these reports

[Area-51]

1 hour ago, Red said:

the rear of the prop shaft on a 912 simply inserts into a bearing in the gearbox casing, there is no way to mount a balance master there, do you mean behind the prop hub?

Exactly; so would require customised insertion device at the opposite end of the prop shaft; in the rear bit.. 😐 🤷🏽‍♂️ 😃

Edited Tuesday at 10:39 AM by Area-51

[skippydiesel]

1 hour ago, Blueadventures said:

Some testers are considering the gear ratio not engine rpm on tacho; therefore 600 rpm of prop may be about 1500 rpm on a Rotax 912.

Fair comment.

 

Hower it is customary, when talking Rotax, to quote engine rpm. The prop & gear box, being driven by the engine, will do their thing, as long as the engine delivers the rpm's🤪

 

I do not know of an aircraft, fitted with a Rotax, that reports/shows prop rpm - may exist somewhere but why?

 

Direct drive engined can be quoted in prop or engine rpm - there being no (discernible 🤣) difference.😈

[Area-51]

1 hour ago, Blueadventures said:

Some testers are considering the gear ratio not engine rpm on tacho; therefore 600 rpm of prop may be about 1500 rpm on a Rotax 912.

No, 600rpm on the tacho.. but only during tuning and balancing; idle speed is 1800rpm during normal operation

[Area-51]

1 hour ago, skippydiesel said:

I am intrigued - what empirical tests have you done, to back up what reads as human perception?

 

Dont get me wrong - I love the idea , I just want proof it actually works. Without proof, it becomes faith, which I have little time for😈

I put glass of water with small frog in it and rest it on the top of the instrument panel.. if the water vibrates, it is bad. If the water does not vibrate, it is good... if the frog moves, the frog moves; means nothing, but is noted anyway...

[Blueadventures]

6 minutes ago, Area-51 said:

No, 600rpm on the tacho.. but only during tuning and balancing; idle speed is 1800rpm during normal operation

All good; I was referring to MoneyBox's comment.  Your 600 tacho is very good balance wise.  Cheers.

[Blueadventures]

21 minutes ago, skippydiesel said:

Fair comment.

 

Hower it is customary, when talking Rotax, to quote engine rpm. The prop & gear box, being driven by the engine, will do their thing, as long as the engine delivers the rpm's🤪

 

I do not know of an aircraft, fitted with a Rotax, that reports/shows prop rpm - may exist somewhere but why?

 

Direct drive engined can be quoted in prop or engine rpm - there being no (discernible 🤣) difference.😈

Agree however the Dynavibe is counting rpm off the reflective tape on one blade so its reduction rpm.

[skippydiesel]

38 minutes ago, Blueadventures said:

Agree however the Dynavibe is counting rpm off the reflective tape on one blade so its reduction rpm.

True! Oh Lord of the Vibe.

 

I have a Dynavibe - good for minimising the ips & calibrating the tacho. Still I would revert to Rotax speak, when commenting on engine operating

 

Are you suggesting, referring to Dynavibe, that you have used this device to prove & measure the effectiveness of a Balance Master. ?😈

Edited Tuesday at 11:42 AM by skippydiesel

[Moneybox]

2 hours ago, Red said:

Perhaps moneybox could inform on where he read these reports

 

Try this from Area-61

 

(I use balance master for three years now; its great; mounted behind bolly prop hub.... carbis all balanced 912 purrs very smooth at 600rpm no gearbox rattles; very quiet, no vibration..

 

because prop shaft is divorced from crankshaft a second balance master mounted at rear of prop shaft will deal with residual imbalance of prop shaft. Nobody gives the rear of the prop shaft any attention 👨‍✈️✈️)

[onetrack]

2 hours ago, Area-51 said:

I put glass of water with small frog in it and rest it on the top of the instrument panel.. if the water vibrates, it is bad. If the water does not vibrate, it is good... if the frog moves, the frog moves; means nothing, but is noted anyway...

And if the frog jumps out?? .... does it mean you do the same??