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jrthomas
12-21-2019, 07:20 AM
Has anyone tried this? https://www.youtube.com/watch?v=iZ8GqUNUcbM

efwd
12-21-2019, 08:42 AM
Yes, some people have tried it. Larry just put one on Mangy Fox and he gave it great reviews. Others have used them on trucks etc etc. It works. Search it here on the forum and you should find the thread. It was just last week that Larry posted on it I believe.

Av8r3400
12-21-2019, 11:17 AM
I’ve got about 5 hours on it now. Combined with a 72” 2-blade Luga prop. She is smooooooooth.

Even the dreaded 2500-3500 normal vibration is totally gone!

jrthomas
12-22-2019, 10:50 AM
I guess maybe I'm just trying to improve something that ain't broken. Mine is very smooth thru the whole rpm range. I have a model 4/912ul with the Kiev 3 blade. Leaf has this and it seems like a good price compared to the price that others are asking. https://www.leadingedgeairfoils.com/propellers/balance-master/propeller-balance-master-6-hole-prop-black-anodized.html (I don't know why this won't highlight.)(Not sure if this is the right one since it doesn't say 912)
It's cheaper than the coolant cap that I recently ordered. My flyin buddy, also with a model 4/912, has a rough midrange. He has a Warp Drive prop. Lots of work, even new carburetors haven't completely cured the problem. I'm really trying to spend some of his money hoping it will cure his problem. I think I'd probably get one myself just to insure mine is as smooth as possible. Should help the gearbox live longer too.

WWhunter
12-22-2019, 04:26 PM
Wow! That's half the price of what I have seen.

Av8r3400
12-23-2019, 06:07 AM
... https://www.leadingedgeairfoils.com/propellers/balance-master/propeller-balance-master-6-hole-prop-black-anodized.html...


I do not believe this is the one for a 912. The photo may not be of the actual unit, but the center hole and slot proportions are not correct for a 912. All of the other sources for a 912 ring are between $150 and $200.

avidflyer
12-23-2019, 06:38 AM
Looking at this $76 balance master, it says it fits the 75mm and 100 mm bolt pattern. The way I see it, this means it would fit on a rotax 2 stroke gearbox with the 1" boss in the center and it looks like the bolt slots are for an 8 mm (5/16") bolt. The real early 912s had a boss that measures about 1 5/16" and has 100mm bolt pattern, and the later 912s are about 1 3/4" boss with 101.6 mm bolt pattern. Long story short, I think Larry is correct. JImChuk

jrevens
01-07-2020, 04:22 PM
There has been a recent conversation about these devices on Shadowrider's build log... thought I'd bring it back over here. Larry's comments, as well as the fact that Hal Stockman was involved means a lot to me, and is also why I decided to get one and hopefully do a little testing. The price is not unreasonable, and worth it to me if there is truly some advantage over a good dynamic balancing job. Regardless of the fact that Balance Masters says you should not dynamically balance before using it, and that any weights should be removed, that just doesn't make any sense in my mind. Here are some comments from a Pilots of America forum back in 2015, where they were discussing these devices. I believe these were not Rotax powered aircraft. I thought they might be interesting to this group. The comment about seeing "smooth operation throughout the operational range (after a dynamic balancing) if they show smooth on the ground" is consistent with my experience. There is generally a good improvement throughout the range. The one stating that "If I balance an engine say at 2400 RPM to .04 IPS and test again at 2000 RPM it is going to be way off" has not been my experience at all... I see it as best at the balanced RPM, but usually not "way off" at other speeds. Also, the "Seat-O-Pants Meter" comment was accurate, IMO -


"I balance props too using the DynaVibe. Thus I was interested in these things when I first heard about them. Reading about them over time, the most interesting and believable article was one in which a person adept at prop balancing compared using a Balance Master with the results of a conventional dynamic balance, on a prop/engine that had been deliberately put in an out-of-balance condition. The results as I recall were that the Balance Master improved the situation, rendering .11 -.13 IPS. With the Balance Master removed, the person with the balancing equipment was able to get it easily below .07. My take on them, just reading . . . all second hand . . . is that they can improve an out-of-balance condition, but will not improve it as well as a good dynamic balance job."



"But the dynamic balance is only good at a certain RPM, and on the ground. I am very interested to see if these work at all RPM ranges and pitch angle of the props.
I have a plane that I can get down to .07 IPS, but in the air it is still rough. I am leaning towards a constant speed prop issue rather than and out of balance issue. I'm hoping this gizmo will help.
I might be overly optimistic, but it will be fun to see."






"Where I'm going with this is once it is balanced, any excessive vibration is likely not a result of simple dynamics. Our engines generally operate in a fairly narrow RPM range so balancing it at a particular RPM is not a big deal."





"I'm curious about how many folks experience vibration problems after a dynamic balance? What I've seen is that the engine/prop are smooth throughout the operational range if they show smooth on the ground. Maybe not perfect throughout the operational range but pretty darn good."


"Balancing certainly makes a difference, but anyone that dynamically balances knows that the balance is only good at a certain RPM. If I balance an engine say at 2400 RPM to .04 IPS and test again at 2000 RPM it is going to be way off. I have seen it go to .15 IPS easily. This "constant balancer" should work at all RPM ranges."


"Do you think you're finding a harmonic? I don't think so. On certified equipment the RPM with that type of problem would be either "avoid" or prohibited.
I think you're seeing an engine problem which might be a simple thing like slightly fouled plugs or an intermittent plug wire failure.
Possibly harmonic, but in my experience all airplane engines with props seem to do this. This is why we balance to cruise RPM, or as high as we can get static.

The difference between .15 & .04 IPS to the pilot (seat-o-pants meter) is pretty small. They might not even be able to feel it depending on the airframe."

Shadowrider
01-07-2020, 05:00 PM
Thanks John. Curious to see your results. Also I am going to put the weights back on mine that had me down to .05 and see if what it feels like with the BM and I will report back. Sorry no official data will be recorded other than seat of my pants.

Dorsal
01-08-2020, 11:17 AM
Mine just arrived today, the comments that it may smooth out some of the transition rpms is what convinced me to try it. Will report measured results (ips/rpm) when my traveling Dynavibe is back home.

PapuaPilot
01-08-2020, 10:09 PM
Does anybody know if they make one that fits on the Continental IO-240? I like the idea of having your prop & engine in balance at all RPMs.

Av8r3400
01-09-2020, 10:35 AM
If you follow the link to ACS, you’ll see they do. John and others have stated they weren’t happy with the results on a direct drive engine. I would hypothesize that the harmonic pulses in a direct drive situation may negate some of the balancing properties.

rdooley79
01-14-2020, 07:57 PM
I’m finishing a 912 install on my 4. Hal did the build of the engine for me and he recommended using two balance masters. One on the mag end and on the prop as well so I put them on my 912. Probably a couple weeks from first run up and no pirep yet. Hal recommended it highly so there’s that...

littlecricket
01-18-2020, 11:48 AM
Two??? I was looking at getting one... now, I have to look at getting two... 😜

rv9ralph
01-18-2020, 07:05 PM
Two??? I was looking at getting one... now, I have to look at getting two... 😜

So here is something to think about. In the Rotax 912/14/15 series there are two centers of rotation. The prop hub at the top of the gearbox, and the Crankshaft (I know the camshaft is also a different center of rotation but we will leave that one for now). These are separated by 4-6 incise. The prop and it's rotational forces are turning at 2.27 or 2.43 times slower than the crank's rotational forces. When trying to balance this, you have to consider both of these sources of acceleration.

To this, the suggestion of two balance masters does make sense.

Ralph

ps - I am not an engineer nor do I claim to be.

efwd
01-18-2020, 08:53 PM
Hmmm. I used a Dynavibe to balance my prop. It worked and I may even swap to the balance master regardless. I seriously hope my $22k Rotax was balanced at the factory.

rv9ralph
01-18-2020, 09:29 PM
I used a Dynavibe to balance my prop. It worked and I may even swap to the balance master regardless.
Eddie, didn’t you report you only had a small vibration that popped up at certain times... could it be a multiple of the reduction ratio? Just a thought.

Ralph

jrevens
01-18-2020, 10:21 PM
23899239012389823900
I flew for 1.5 hours on 1/16/20 with the Balance Master installed. The airplane didn't feel as smooth as before, but definitely smoothed out more after full throttle run-up. Today I installed my balancing equipment to get some real numbers. After warm-up, I advanced to 5000 rpm, took a vibration reading, then did the same thing at 4000, 3000 & 2000 rpm. I then went back up in 1000 rpm steps to 5000. I then removed the Balance Master and performed the same exercise again. I had previously dynamically balanced the assembly to 0.02 to 0.03 ips at full-throttle static of approximately 5100 rpm. Here are my results and observations -

With Balance Master - Starting at 5000 rpm - 0.04, 4000 - 0.04, 3000 - 0.12, 2000 - 0.02 Starting at 2000 - 0.03, 3000 - 0.07, 4000 - 0.03, 5000 - 0.10

Without BM - Starting at 5000 rpm - 0.02, 4000 - 0.02, 3000 - 0.01, 2000 - 0.02 Starting at 2000 - 0.02, 3000 - 0.02, 4000 - 0.03, 5000 - 0.03

I allowed time for things to "settle down" before each reading, and observed that with the BM it took a minimum of 30 sec. to 1 min. (sometimes considerably longer) to reach the best balance condition. There was no delay without the BM. I'm not certain why the spike at 5000 rpm when going from 4000 to 5000 with the BM as compared with starting at 5000. Hysteresis in the throttle cable when pushing as opposed to pulling on the throttle arm (I don't have the throttle springs) creating a little carb imbalance may be a factor, but I don't see the same thing without the BM.

So, my experience is smoother operation without the Balance Master, and much smoother during the transition "settling down" periods. I think that the Balance Master would potentially offer a good improvement/option for an out-of-balance condition if dynamic balancing was not easily accomplished, such as when a small "skull-cap" spinner is used on a Rotax. For me, there is no doubt that my situation is better with a good dynamic balance job alone. Your mileage may vary.

Clark in AZ
01-18-2020, 10:42 PM
Very interesting. Thanks much for taking the time to do this and report the findings. Maybe some others will chime in with their findings.

Clark

JoeRuscito
01-19-2020, 06:25 AM
Great report. Thanks John.

Dave S
01-19-2020, 06:34 AM
John,

It's great to see some empirical data on this.

rdooley79
01-19-2020, 08:41 AM
So here is something to think about. In the Rotax 912/14/15 series there are two centers of rotation. The prop hub at the top of the gearbox, and the Crankshaft (I know the camshaft is also a different center of rotation but we will leave that one for now). These are separated by 4-6 incise. The prop and it's rotational forces are turning at 2.27 or 2.43 times slower than the crank's rotational forces. When trying to balance this, you have to consider both of these sources of acceleration.

To this, the suggestion of two balance masters does make sense.

Ralph

ps - I am not an engineer nor do I claim to be.


I was thinking of this as well. The Balance Master on both rotational masses makes a lot of sense. Being able to balance both masses would stand to reason to smooth the running of the engine. I'm not sure but it seems that any change in resonances might effect that also. The active balancing effect of mercury in the ring of tha balance master plate would be constantly changing to accomidate any differences. Also as an engine breaks in over time things will change and might effect the balance ever so slightly (might be total bs here....) but with the active balancer on both masses those slight variations would be addressed by the balance master.
The weight of the balance master is very negligable. It seems that any weight addidtion would be negated by the theoretical longevity of the engine/wear/carb balancing due to vibration as well as enjoying a nice smooth running engine.

Being that I have a freshly built zipper 105hp engine the access was easy and installing the plate on the rear of the engine was quick. Looks like it could still be done with the engine on the plane but it's a lot tighter and may need to move the oil tank. dont forget to use a crank locking pin and that it's seated in the groove of the crank before using the breaker bar/torque wrench.

haha, I made a couple videos of the install months ago and forgot that they are already uploaded to YouTube.

https://youtu.be/tJJIeM1EM9w



https://youtu.be/TNhhX78J0U4

Dorsal
01-19-2020, 10:46 AM
23899239012389823900
I flew for 1.5 hours on 1/16/20 with the Balance Master installed. The airplane didn't feel as smooth as before, but definitely smoothed out more after full throttle run-up. Today I installed my balancing equipment to get some real numbers. After warm-up, I advanced to 5000 rpm, took a vibration reading, then did the same thing at 4000, 3000 & 2000 rpm. I then went back up in 1000 rpm steps to 5000. I then removed the Balance Master and performed the same exercise again. I had previously dynamically balanced the assembly to 0.02 to 0.03 ips at full-throttle static of approximately 5100 rpm. Here are my results and observations -

With Balance Master - Starting at 5000 rpm - 0.04, 4000 - 0.04, 3000 - 0.12, 2000 - 0.02 Starting at 2000 - 0.03, 3000 - 0.07, 4000 - 0.03, 5000 - 0.10

Without BM - Starting at 5000 rpm - 0.02, 4000 - 0.02, 3000 - 0.01, 2000 - 0.02 Starting at 2000 - 0.02, 3000 - 0.02, 4000 - 0.03, 5000 - 0.03

I allowed time for things to "settle down" before each reading, and observed that with the BM it took a minimum of 30 sec. to 1 min. (sometimes considerably longer) to reach the best balance condition. There was no delay without the BM. I'm not certain why the spike at 5000 rpm when going from 4000 to 5000 with the BM as compared with starting at 5000. Hysteresis in the throttle cable when pushing as opposed to pulling on the throttle arm (I don't have the throttle springs) creating a little carb imbalance may be a factor, but I don't see the same thing without the BM.

So, my experience is smoother operation without the Balance Master, and much smoother during the transition "settling down" periods. I think that the Balance Master would potentially offer a good improvement/option for an out-of-balance condition if dynamic balancing was not easily accomplished, such as when a small "skull-cap" spinner is used on a Rotax. For me, there is no doubt that my situation is better with a good dynamic balance job alone. Your mileage may vary.

Just the experiment I was planning on running, might still to verify results.Quality work as always John, thanks.

Clark in AZ
01-19-2020, 12:35 PM
Just the experiment I was planning on running, might still to verify results.Quality work as always John, thanks.

It will be interesting to see if you have the same results...

Clark

Shadowrider
01-21-2020, 09:37 PM
John I questions your numbers. Did you get confused and balance a turbine? That’s some smooth readings. Wonder if you tried the BM with dynamic balanced weights or without weights? Curious if it’s true its better without weights. I put my weights back on to try flying with the BM and balance weights that had me at .05

jrevens
01-21-2020, 11:45 PM
Hi Dustin,

I never removed the weight that I had installed during dynamically balancing it. I know that Balance Masters says you should remove any balance weights, but I still don't buy that. As I've said previously, I think it might be a marketing strategy on their part. The Balance Master device has no way of knowing that there is a small weight that is making the propeller well-balanced to begin with, and if a well-balanced assembly is not as well balanced after installation of the Balance Master... well, what can I say? These are just my observations and experience... I'm open to any discussion or disagreement. I found out a long time ago that what I believe is not always right. As far as the smoothness goes, yes - I do have a very well-balanced propeller assembly. Anyone who has done a lot of them, like I have, can tell you that there is just a little bit of "art" involved, even with the modern balancing devices. I do think that the ACES machine is a little easier to use than the Dyna-Vibe that I saw a few years ago. My ACES unit is an older one - the mod. 1000.

Shadowrider
01-22-2020, 06:50 AM
Nice! Sorry I hope you know I was being sarcastic because of your very smooth readings. You defiantly have a smooth readings. Best I could get was .05 only at 5000rpms. Everywhere else it was all over the place. Yeah I took the weights off because of BM recommendations. Bm explanations made sense to me but I can see it both ways. I figured I would listen to him since he has more experience than myself. I am curious though if running weights or no weights is smoother or how it effects balance with BM. I put another hour on mine and as far as mine goes it’s defiantly smoother, in the air. What kind of prop are you running? Mine defiantly feels smoother in a steep climb with high AOA with BM. I am running a NR prop that is carbon. I noticed it has flex in it and I can see the tracking changing (in my mind) at different AOAs when p factor comes into play. When this happens vibrations happens that the BM is overcoming. Just a couple thoughts I had why we had different results. I was going to buy a balancer and was looking at getting the aces to balance my prop yearly. I know it doesn’t take much to effect balance. Ultimately it came down to my prop was very difficult to balance, partly because the setup was initially wrong on the G3X but maybe these props are just harder to balance. On 53TF we are just putting on a BM and skipping balancing it.

Clark in AZ
01-22-2020, 07:10 AM
Dustin, it will be interesting to see how the other prop balances. It seems like you guys pretty much built a carbon copy of your plane. I wonder if you'll encounter the same issues with this one?

Clark

jrevens
01-22-2020, 10:02 AM
Nice! Sorry I hope you know I was being sarcastic because of your very smooth readings. You defiantly have a smooth readings...

Dustin,
Nope... I understood, and your comment was appreciated! My prop is a 70” 3-blade Whirlwind. Every combination of engine, prop, & spinner can be different in how easily and well they can be balanced. I think I got lucky with what I have. I’m really glad the Balance Master works so well for you, Larry, & others! To further the conversation a little, when you conventionally balance a prop assembly it needs to be realized that it is only that individual assembly that is considered. Especially with a Rotax, having a PSRU between that and the engine since they are not fully “in-synch” the same way with every revolution of the propeller. I’m not familiar enough with Dyna-Vibe, but with my balancer “random” vibration events that may occur other than every 180 & 360 degrees are “filtered out” when the machine calculates the solution of necessary weight & position. This makes sense since a fixed balance weight on the propeller is not going to necessarily balance anything that may be causing vibration in the engine or gear box. An additional Balance Master on the engine sounds interesting. Again though, my situation tested better not only according to my balancer, but also “feel” on the ground & in the air.

Frontier Fox
04-22-2020, 08:01 PM
Was wondering what the consensus was on the Balance Master. It looks like some had good results and others marginal results. I will be putting my prop on soon (Airmaster, Whirl Wind blades) on a Rotax 912iS. The question is: do I Dynamic balance with a Dyna-vibe or put on a Balance Master and call it good? Help me decide!

Joe

Shadowrider
04-22-2020, 08:21 PM
Joe on the NR prop I got better results with balance master. Others have got better results with a dynamic balance. Dynamic balancing is mostly science and partially an art form. If you have never dynamic balanced a prop and will be doing it by yourself, I say just run the balance master. Maybe John will sell you his?

jrevens
04-23-2020, 11:56 AM
With the early dynamic balance equipment that was available 30 years ago, i.e. from Chadwick-Helmuth, there was some “art” involved in my experience. With modern technology, not so much. I don’t have any Dyna-Vibe experience, but with my 20 year old ACES machine it’s all science. I’ve given my Balance Master to a friend to try on his Mod. IV. If he doesn’t like it I’d be happy to sell it.

Av8r3400
04-23-2020, 06:33 PM
Having done both on my plane, I now have a Balance Master ring on it.

I can not quantify anything scientifically the way John did, but my "seat-o-the-pants" meter sure liked the results of the ring better.

Frontier Fox
04-23-2020, 08:30 PM
I appreciate the responses from everyone.

With a new Rotax 912iS it makes no sense to me to install a Balance Master on the flywheel. It would void the warranty and it seems that the engine should be balanced to begin with. However, I would expect some imbalance within the prop hub and blades. That’s a lot of mass spinning a 70”+ circumstance. So I’m leaning towards the Balance Master for its simplicity.

I’m probably about three or four weeks from my first start so I’ve got some time to make a decision.

John, if your friend does not want your Balance Master let me know, I may want it.

Joe

jiott
04-23-2020, 10:00 PM
I don't have any problem with the idea of a balance ring that automatically distributes its balance weights AS IT IS SPINNING. What bothers me a whole lot is the initial start-up when the weight has all fallen to the bottom overnight and it must be redistributed on start-up. Even if it only takes a couple of seconds (some reports on this thread indicate it may take 30 seconds) that is too much time to have what may be a very out-of-balance condition on EVERY start-up. If your engine rubber, especially the carb sockets, is getting older and approaching replacement time, a couple of hard shakes on each start-up could easily cause a crack. We also know that hard shaking or pulses is bad for the gearbox/clutches. I personally feel much better with a good dynamic balance; its not that hard to do or that expensive to have it done. Just my opinion.

Shadowrider
04-24-2020, 12:10 PM
I think these rotax engines experience more force on the rubber mounts when they are shutdown than starting up. Still can’t get used to the prop just stopping.

jrevens
04-24-2020, 07:24 PM
I think these rotax engines experience more force on the rubber mounts when they are shutdown than starting up. Still can’t get used to the prop just stopping.

Dustin,

I think it was DesertFox4 who turned me on to the technique I use to shut-down - from 2500 RPM, simultaneously pull throttle smoothly to full idle while turning off ignition (in my case, 2 toggle switches). The result for me is a rather smooth shut-down... not at all bad. Not like an engine without a PSRU, but still pretty good.

Av8r3400
04-24-2020, 07:37 PM
I don't have any problem with the idea of a balance ring that automatically distributes its balance weights AS IT IS SPINNING. What bothers me a whole lot is the initial start-up when the weight has all fallen to the bottom overnight and it must be redistributed on start-up. Even if it only takes a couple of seconds (some reports on this thread indicate it may take 30 seconds) that is too much time to have what may be a very out-of-balance condition on EVERY start-up. If your engine rubber, especially the carb sockets, is getting older and approaching replacement time, a couple of hard shakes on each start-up could easily cause a crack. We also know that hard shaking or pulses is bad for the gearbox/clutches. I personally feel much better with a good dynamic balance; its not that hard to do or that expensive to have it done. Just my opinion.

I don't know where the 30 seconds indication came from but I can observe my engine is running smooth before the CDI modules kick the timing to the "run" position. That may be 3 seconds.

jiott
04-24-2020, 08:50 PM
The 30 second reference was from John Evans post #18:
"I allowed time for things to "settle down" before each reading, and observed that with the BM it took a minimum of 30 sec. to 1 min. (sometimes considerably longer) to reach the best balance condition. There was no delay without the BM."

Very likely John was saying it took that long to reach a very fine balance condition. I doubt he meant that there was major shaking for that long. I will bow out of this discussion at this point because I have no actual experience with the Balance Master. I was just expressing my opinion after reading what others have posted and my own thinking on the subject.

Shadowrider
04-24-2020, 09:47 PM
Thanks John. I have been doing 2000rpm. I will try 2500rpm to see if it’s any better. It’s like a main bearing is dragging and on its way out. Kind of comical how a rotax stops. Still getting used to it.

As far as the BM being out of balance on startup... I bet the mercury is spun out on the crank before the engine is idling smooth.

jrevens
04-24-2020, 10:01 PM
...
Very likely John was saying it took that long to reach a very fine balance condition. I doubt he meant that there was major shaking for that long...[/COLOR]

That's exactly right, Jim. To try to further clarify... when you're looking at the vibration level sensed by the accelerometer, it is generally far more sensitive than what you can "feel" inside the airplane. I'm talking about not only minor, but also significant vibration levels at the engine in many instances. By significant I mean that they are worth reducing or eliminating, for all of the reasons that have been discussed.

jrevens
04-24-2020, 10:28 PM
...
As far as the BM being out of balance on startup... I bet the mercury is spun out on the crank before the engine is idling smooth.

I'm sure it is too, but during my testing it took much longer, as I noted, for things to get to a "respectable" level & as good as it was going to get, and then it varied throughout the run. I just tried to report accurately what my results were, and the test was only with my particular engine, propeller and spinner . I'm not saying it was "bad" with the BM, but just that it was better without it (with a good dynamic balancing job). If the BM had produced better results, or at least as good, believe me I would have kept it. I'm hoping it will make a good improvement for my buddy Stan, with his IVO prop and small "skull-cap" spinner - a set-up that is difficult to effectively add balance weights to.

Regarding the shut-down technique, it took me a little trial & error before getting it just right... the timing when shutting off the ignition in relation to the throttle movement seems to be the key.

Shadowrider
04-25-2020, 10:27 AM
Understood John.

With regards to the “correct” technique. Even with “correct” technique....it’s like the Gerbals just stop running and get stuck in the wheel. Never being around a rotax, they raise eyebrows when shutdown.

jrevens
04-25-2020, 08:40 PM
Yes they do! :rolleyes:

jrevens
05-09-2020, 10:14 AM
Just want to provide an update. We installed the Balance Master on Stan’s Mod. IV yesterday. He’s got an Ivo 3-blade IFA with the small “bullet” spinner, and 80 hp 912. The vibration level before the BM was considerable at 0.73 ips (inches per second of acceleration). After installing the BM, the level measured between 0.49 & 0.53 ips throughout the rpm range and at various pitches. This is an improvement, but disappointing. We normally aim for a level of 0.05 ips or less when balancing with fixed weights (anything less is really just “splitting hairs”). I think we may do some further testing, and if so I’ll report the findings.

efwd
05-09-2020, 11:51 AM
Im curious. I had my ips down at an acceptable number. Thought it was smooth, and it was, definitely better than before I used the Dynavibe. Then, one day recently, I adjusted my prop pitch for something between cruise and climb since the climb setting made it too easy to overspeed the engine while in flight and not necessarily climbing with full throttle. I recall paying very close attention to getting the pitch in each blade as near as exactly the same as I could. Much like the time I did it for the first time before I got my sign off. When I flew it I believe I noted an appreciable improvement after that prop adjustment. In your case John, you didn't seem to get such great results with the balancer which leads me to the question. How much could the prop be influencing the ips if a blade is off too much?

jrevens
05-09-2020, 12:17 PM
That's a good question, Eddie. If you're talking about prop pitch differences in the 3 blades then yes, it can/will cause vibration. I'm not very well educated in this area, but it would seem to me that the vibration would be created axially, or basically parallel to the prop shaft, as opposed to an imbalance in weight that produces vibration perpendicular to the shaft. Either way, it's unwanted vibration. I'm sure someone on this forum could correct or clarify my crude knowledge about this. I don't believe adding balance weight or a Balance Master will correct vibration due to pitch variance among the blades. So if this is true, the IFA Ivo prop may create vibration, depending on variance in pitch between the blades, that isn't easily corrected.

Just to make sure it is clear, I haven't been able to add conventional weights to this assembly because of the small spinner and hub. I've merely used the balancer to measure the amount of imbalance.

Delta Whisky
05-09-2020, 07:28 PM
John - I sure can't clarify - in terms of a solution or answer - but maybe more anecdotal information may help develop a provable theory. In testing a 60kW electric motor directly driving a prop by a well known and reputable American company we experienced several tests of extremely smooth performance through the complete rpm range. Then, during some tests we'd start up thru the range and experience severe vibration - so severe that on at least two occasions the test stand would jump an inch or two off of the ground. We were working on a theory that differing incoming wind angles (that was the only thing in our set up that we knew had changed) was the culprit but ended up shutting down the company before being able to prove anything.

JMH
06-17-2020, 04:49 PM
I was interested in trying the Balance Master, so I ordered the prop Balance Master off set. And it doesn’t fit.
I have a Rotax 912iS, with whirl wind prop 70” ground adjustable. Anyone have a suggestion as to which balancer I need? I ordered from ACS and the other Balance Master products they offer are for the engines.
Thanks
John

efwd
06-17-2020, 07:26 PM
Part# 15-09450 MFR Model# UL-912-914 isn't the correct one? Thats the bolt pattern I would expect as I have the same setup. I pulled that from ACS&S website.

JMH
06-18-2020, 04:34 AM
I ordered part no. 15-05828. Maybe the part no 15- 09450 is the correct one, I thought the one I ordered was for props, and the others bolted onto the engine. I was hoping someone who has purchased one could confirm that. Thanks for the reply.
John

Maverick
02-03-2021, 11:44 AM
Eddie, did you buy a Balance Master? If so, what is your opinion of the Balance Master? I have the IvoProp IFA. Were there any issues installing the flywheel? Would you do it again?

Fred

efwd
02-04-2021, 09:27 AM
I did not buy the balance master. The dynavibe did a nice job as far as I can tell. If I recall, John had put up a post on his findings and I went with that. Dave put one on his KFS7 without using the Dynavibe and he was very pleased. He is using a Whirlwind IFA prop.

Maverick
03-26-2021, 09:25 PM
I took a bullet on this and bought a Balance Master. I have to say, I am impressed. But, let me be completely honest. I nosed my plane into the dirt and ruined my 72" IvoProp. I replaced it with a 70" and I put on the Balance Master at the same time. I was getting some vibration but it wasn't devastating. I just didn't get the smoothness I anticipated however, having put the subsequent prop on at the same time I decided to pull the prop and switch two of the blades around in position and bingo. I found a sweet spot. Now when I pull the power to descend it is smooth in most all RPM ranges and in the dreaded 2700-3300 range the vibration I get a far more comfortable experience. Climb and cruise is very much more pleasant. I think had a dyna-vibe been available to me, I would have gone for it but in the absence of one, I'd do the Balance Master again.