Dynamic Prop balancing

[brilin_air]

Hi Bruce,

 

I have 6 EGT and CHT thermocouplers that get fitted under the sparkplugs and clamp to the exhaust which the cable then comes into the cockpit and connects to a MGL TC3 reader, it gives you the ability to use 1 to 12 termocouple senders and gives a live reading much the same as a Dynon and when you come back and shut down you can get the hottest temps that each thermocouple has reached as it is stored in memory until you clear it. Everything fits into a box about the size of a fishing tackle box and can be fitted and removed once you are happy with whatever you are trying to solve, whether it is to check the senders or guages that are in the plane or trying to get more even cooling through air ducts without mounting permanent senders.

 

Brian

 

 

[Bruce Robbins]

Thanks Brian,

 

I have Dynon gear in three of the aircraft I'm operating, so already have the instrumentation. Was more interested in your thermocouples, particularly the EGT.

 

Are they also from MGL?

 

I presume the EGT clamps to the exhaust headers with a probe up against the tubing. If so, do you know what sort of accuracy you get, or is it just the comparison of temp spreads you're after?

 

Thanks,

 

Bruce

 

 

[brilin_air]

Bruce,

 

At the moment I am just looking at temp spread over the whole engine as I haven't fitted it to an aircraft with internal probes to compare it against, the exhaust senders just clamp onto the pipes and give a reading of pipe temp, but you can still see a variation on cylinders if they are running rich or lean, It's a compromise that allows you to get information without altering anything on what you are checking.

 

Brian

 

 

[Bruce Robbins]

OK, thanks.

 

 

[jetjr]

I just used a borrowed Dyna vibe to balance two propellers and had some problems but the machine worked great, a 3 and new design 2 blade Bolly props

 

Under advice I taped washers onto hub whilst balancing, ended up the tape let go and a washer struck a blade - a big but only cosmetic chip which had to be repaired

 

The 2 blade was found to have a static balance problem and had to be returned to manufacturer, seems tip weight had come out. Dyna Vibe indicated this pretty clearly but it wasnt a surprise as it was clear something was wrong BUT ive flown behind standard Jabiru props which vibrated worse

 

Dyna vibe was then used on the original - now repaired 3B prop, which I thought was fairly smooth and showed readings over 0.72 ips. With around 20 g of washers it came down to 0.07. Just four runs and adjustments and the difference is amazing. I could have gone further but this isnt the final prop Ill be using so that will do.

 

Its a Jabiru 6cyl and it truly is much smoother, Scares me what some of the vibration levels on Wooden props Ive had on there must have been.

 

Great bit of gear and this one is for sale but not sure how to justify the cost.

 

 

[brilin_air]

Sounds good jetjr, yes the balancer looks to be easy to use and the more you use it the easier it will become to know how much weight to put on, I just think that the smoother things can run the better it has to be on the whole engine and airframe. I have spoken to someone who also has one of these balancers and they have sent me pictures of the way in which the balancer was fitted to their engine so I am in the process of making the mounting brackets to suit what I need.

 

Brian

 

 

[brilin_air]

Finally made the bracket to fit the balancer and tried it today, started with .08 ips out of balance which according to the book is not bad, but I had a play and got it down to .02 ips, great to use and easy once you have worked out how much weight and where to put it.

 

Brian

 

 

[Vev]

Hi Brain,

 

Sounds great mate ... 0.02 is a fabulous result.

 

Come on over to Tyabb and you can have a go at my two ac ... I'm sure there will be others interested too?

 

Cheers

 

Vev

 

 

[brilin_air]

Hi Vev

 

haven,t been to tyabb yet, it is on the list of places to visit. It would be great to catch up again

 

Brian

 

 

[billwoodmason]

Hi Brian,

 

I would love to have my J230 prop dynamically balanced so if you feel like a trip to Cobden (Vic.) that would be great. (or I could come to you)

 

PS Was that your aircraft outside the Jabiru forum hanger at Temora.

 

Bill W.

 

 

[xair1159]

For a more affordable dynamic balancer, have a look at this from Smart Avionics:

 

http://www.smartavionics.com/prod-pb.html

 

I have used a PB1 successfully for some years now. Would like to update to the PB3 which looks easier to set up with Bluetooth instead of hard wired and a better display. Hard to justify when the one I have is working perfectly and gives good results.

 

 

[brilin_air]

Hi Brian,I would love to have my J230 prop dynamically balanced so if you feel like a trip to Cobden (Vic.) that would be great. (or I could come to you)

PS Was that your aircraft outside the Jabiru forum hanger at Temora.

 

Bill W.

Hi Bill.

 

Whatever is easiest for you. A cuppa and a biscuit are always here at the marsh.

 

Let me know, I am always looking for a reason to go for a fly. :)

 

And yes, that was our 160 at Temora.

 

Brian

 

 

[Robertvn]

Finally made the bracket to fit the balancer and tried it today, started with .08 ips out of balance which according to the book is not bad, but I had a play and got it down to .02 ips, great to use and easy once you have worked out how much weight and where to put it.Brian

Hi

 

Sorry to bother you on such an old post, BUT I ave borrowed a Dyna-Vibe and was wondering where you fitted it to the Jabiru engine? I noted that someone had sent you a photo of their bracket, would appreciate it if you still had it.

 

Cheers

 

Robert

 

 

[Kyle Communications]

You just need a bracket somewhere on the front of the engine preferably near the centreline. Mine is a rotax bracket but the guy I bought it off I am sure had brackets for a Jab engine. I have them here in the box I will take some pics and post them of the different brackets I have. I use a Rotax and had to make my own but it was pretty simple

 

Mark

 

 

[Kyle Communications]

Here are the brackets...the sensors are mounted on my Rotax bracket

 

 

 

 

 

 

 

[Robertvn]

Here are the brackets...the sensors are mounted on my Rotax bracket[ATTACH=full]36611[/ATTACH] [ATTACH=full]36612[/ATTACH] [ATTACH=full]36613[/ATTACH] [ATTACH=full]36614[/ATTACH] [ATTACH=full]36615[/ATTACH]

Thanks for the pics, Ill see if any of these look like they could work on a Jabiru engine, Jabiru engines don't have a lot of accessible bolts to work from. I had noticed that brilin_air had made one specifically for a Jabiru, so was a bit interested where he mounted it.

 

Cheers

 

Robert

 

 

[brilin_air]

Hi Robert, Here are some pics of the mount that I use. It is mounted to the top of the engine where the crankshaft seal mounts, the accelerometer is central and the inductive pickup is to the side. Take your time and good luck it is very sensitive and reaching for perfection can be frustrating but once you get the hang of it you will get results quicker. I use stick on wheel weights on the spinner flange edge where the screws go in and as a guide I have found that 3 grams will give you about .1 ips correction. If after your first measurement you are getting near 1 ips take your prop off and check for static balance first as the closer you can have everything statically balanced it makes it easier to dynamically balance.

 

Brian

 

 

 

[facthunter]

Faster aircraft have less of a problem. Nev

 

 

[biggles]

Faster aircraft have less of a problem. Nev

This one is pretty quick . Not your garden variety 160 ! .... Bob

 

 

[Robertvn]

Hi Robert, Here are some pics of the mount that I use. It is mounted to the top of the engine where the crankshaft seal mounts, the accelerometer is central and the inductive pickup is to the side. Take your time and good luck it is very sensitive and reaching for perfection can be frustrating but once you get the hang of it you will get results quicker. I use stick on wheel weights on the spinner flange edge where the screws go in and as a guide I have found that 3 grams will give you about .1 ips correction. If after your first measurement you are getting near 1 ips take your prop off and check for static balance first as the closer you can have everything statically balanced it makes it easier to dynamically balance.Brian[ATTACH=full]36622[/ATTACH] [ATTACH=full]36623[/ATTACH]

Thanks for that Brian

 

Ill try and make a bracket tomorrow, I may have to turn it around as my prop may be closer to the motor than your 160

 

Will let you know how I get on, could be a couple of weeks before I get it sorted though.

 

Cheers

 

Robert