How to balance a compressor pt. 2 - A Closer Look

Fixing the blades for balancing, and spinning up the disk to see how we're doing. Also a cameo from shop kitty.

[ziggs]

Fascinating channel man...being able to see this far into turbines is a real treat thank you!

[AgentJayZ]

@1metiz There is merit to your comment. But, we can't risk blades flying out.
So we try to apply a consistent ring of tape, hopefully minimizing any effect it may have.
... all the while keeping in mind we are attempting to balance an assembly of dozens of parts, all of which can move relative to one another...

[AgentJayZ]

@bashue69 Good question.
No it's not, because we do not add or remove any material to or from the disk.

Many rotating machine parts are balanced by grinding material off a supplied "balance weight" area which is thicker and can be ground without losing strength.
This engine does not allow for material removal on the compressor ( or turbine) disks.

[AgentJayZ]

@Xx69roadrunnerxX New parts? It's all unobtanium by now, but it would have been in the tens of thousands when new stuff was being made.
For one stage and the blades it takes.
On a new fighter engine, replacing the entire compressor... just the blades and stator vanes - not replacing the disks or spacers... I'm guessing that would be somewhere north of a half mil.
That's why runways are so incredibly clean.

[AgentJayZ]

@rxvexe Well, yes and no.
It's not a simple situation that can be turned into an equation.
The reason for that is the blades can move in their slots as the disk speeds up. Then they are locked into position by centripetal force.
Also, as explained in the vid, you may need to make a change that is not available by simple blade-to-opposite-blade swapping.
Sometimes a bit of black magic can smooth the way to success.

[AgentJayZ]

Sure! We don't fully disassemble compressor rotors very often, but when we do, It could be very handy...

[vanloinguyen]

hi there, its so exciting to see this balance, so this test bench you made it Yourself or bought from producer and how exactly it is ??

[mcwrenn]

Awesome clip! At 3:46 in the video you mention you're trying to get the unbalance amplitude to below 1. Are those units of mils representative of mm/s and you're balancing to ISO1940 Grade 1 or are the mils thousandths of an inch (as in just displacement) and you're balancing to a different standard?

[TheGuitlicker]

AgentJayZ, your videos are inspiring thanks for sharing your expertise. I am hoping to get to an aviation maintenance program in the fall. May I ask?; what small business can someone with that training and an AP license get into if they choose the entrepreneurial route. thanks

[GeofreySanders]

Blending the blades changes their shape and therefore their aerodynamics, so a concentration of more heavily-worn blades on one side of the disk would(?) produce uneven thrust. Maybe it's not a problem since the most-blended blades would perforce be the lightest ones, but is there any accounting for the 'age' distribution of the blades as well as weight?

[JasonWaterfalls]

Great vid! How much money is spinning there? Love shop kittys cameos.

[researchinstitute]

Is it possible in modern manufacturing to make blades that are exactly the same mass? If so, that would take care of the balancing issue ... how were the blades actually made in the 1950's?

[metiz]

Won't the tape mess up the balance? if you're juggling with .1 gram, a slither of tape more or less shold make a huge difference does it not?

[TheSock]

I ask this because it looked as though it had a slight wobble. Does the method of mounting it, change the balance?

[SebastianLopez-nhrr]

Hey Jay! Why isn't the weight distribution solved by a computer program whose inputs are the rotor disc's characteristics and the blades number and weights?

[AgentJayZ]

The materials chosen for each part are the result of much analysis and compromise.
For some reason, stainless steel was not chosen. Maybe weight, maybe strength, maybe cost...

[TDDMS]

Can the rotary disc be made out of stainless steel?

[JasonWaterfalls]

@AgentJayZ Wow, thats some serious money! Thanks for the info!

[tusharchawla]

why compressor blades dont have fir tree fixing method and why they have dove tail method

[volkanackgoz]

jay you are speaking very fast so we can't understand you. can you speak slowly next time please and can you add subtitle for this video...