Carbon Fiber blade testing 3 

What a unique opportunity to participate in a potential game changing advancement in the turbine world ! I look forward to see the results.

Fan... tastic. ;-). I`ve made my diploma Work about the Fan Blade Alloy, TI AL 6V4 bending fatigue stress at 200°C and 400°C. 30 years ago. We designed a tast bed for this. In the beginning we tested the fatigue of the test equipment. Science is going forward. Besides, this ORENDA badge triggered me. In 1978 i had a flight with a guy, runnung a Tiger Moth at Lahr Canadian Airbase/Starfighter in Germany. He was an employee of Orenda Companie. Cheers Axel

Extremely exciting to see this process Jay. Thanks for taking us along.

And now a comment on my comments. As a young and very inexperienced designer, in the days when we had things called drawing boards, and dinosaurs roamed the earth, I was told that, "You think with a pencil, you design with an eraser." This is effectively what I've been doing mentally with my thoughts about composite blade testing. However, I've changed one word for the benefit of my more delicate North American readers. What was actually said to me was, "you design with a rubber." I'm aware that the word commonly used for a pencil eraser on this side of the pond means something different over there.

There is so much cool engineering going on here that it is scary exciting!!!

I've had yet another thought about a rig test of a bladed disc. There have been suggestions of a small number of composite blades spaced around the row. No, it really needs a full set to be representative. One clever way of detuning a problem blade row is to have blades of different natural frquencies spaced around the row. The first stage of a small turbofan with which I was familiar some years ago had a mixture of 'A' and 'B' blades to do this.

Fantastic! For abrasion, (and apparently strength) metalize the leading edge like the *GE9X* Maybe even on the Fir Tree/root? From GE- "The new material incorporates a higher stiffness carbon fiber and a new epoxy resin. The leading edge material will also be modified from titanium to a steel alloy to further enhance the blade's strength."

This would be very exciting to be a part of. I'm glad these guys are letting you document this.

11:34 Sounds like a great idea for the long term fatigue testing to have it populated with a minimum number of blades and driven by an electric motor. One question, does it make sense to have the test blade to have a leading companion blade to try to setup the airflow field that is as reasonably comparable to a fully populated assembly? If the airflow fields are too different it might produce different vibrational forcing that could affect the fatigue results. Just wondering, but I don’t know what I am talking about. Also with a more experimental test rig it might be easier to get high speed video or get some strain gauges incorporated into the setup to check on some of the dynamics going on. Also a possibility is to use a pair of optical reflective probes, one at the root and one looking radially inward towards the blade tip to get some dynamic behavior monitoring up on a digital scope.

I can see the excitement. Heck I’m excited. I run LM6000’s and I can imagine the future for the power generation industry.

Long time see. So glad yall still cranking. Thanks

THANK YOU AGENTJAYZ

this whole series is amazing and awesome! keep going!!

Glad to see the exuberance in your work. Will be watching

lovely thing that is!!!

Very cool.

I was able to experience a full aug F-16 engine run at night. It's like a white noise generator at 140db, your entire body just being blasted with concussive sound the whole time it's up over 80% throttle. It's something to experience first-hand for sure.

Good luck 🤞🏼

So I would also think you would need the Stator as well for a electric test stand for the interrupted airflow and what not. Make for one hell of a shop fan though

Cheers from Edmonton.

This is how you handle "HOA Karens"..

I think you're about due for some more fill for Jet Wash Alley.

And now my thoughts about wear in the dovetail root, with a suggestion of electroplating being offered elsewhere. My starting point must be that I learnt as a very new and very 'green' designer that fretting and wear was problematical in industrial and marine engines, as compared to their aero equivalents. They run the whole time in air at ground/sea level and consequently experience much higher cumulative aerodynamic and vibratory loads, hence fretting and wear being such a problem. Modifications to introduce 'hard' wear-resistant coatings were necessary to give acceptable lives. Another mod which was commonly used (and in aero applications) was the introduction of anti-fret liners into compressor vane fixings. Perhaps something similar might be needed for these blades - but first quantify the problem. A static rig test, vibrating a sample root in a disc slot might be a starting point, before going to a rotating rig test, as previously suggested. PS This has kept me occupied as the German countryside has rolled by.

In electronics for military use there is HALT (highly accelerated life testing) and HAST (highly accelerated stress testing). MIL-HDBK-217 might be worth a cursory glance and I think is currently at revision F (public domain on the internet). If it can be done for electronics it can be done for mechanical systems is my guess. It could potentially shorten your test time.

After I suggested using a complete J79 compressor for a rig test, with all of the blades/vanes removed after stage 1, I started to have doubts. So, I thought I'd better remind myself of the actual layout of the compressor. On looking at a cross-section, it is plainly obvious that the barely compressed flow from stage 1 will be constricted long before it reaches the mid frame, and I've now realised that I must now screw my designer's head on more firmly. Consequently, I'm now thinking in terms of cutting some large ports in the casing to exhaust the flow, which might need some external support or reinforcement as a result. Or perhaps even more major surgery might be considered, with both the casing and the rotor 'truncated'? However, this would mean numerous new parts having to be designed and made. It could be a great challenge for a designer. I'm not volunteering, but I'll stand on the sidelines to offer support (and constructive criticism, if necessary).

Another great video.. Thanks for sharing. I wonder how well the blades do with small FOD impacts. My gut feeling is they'd do really well.

G'day Jay, Yay Team ! I'm very impressed with the performance of those Blade-Root Attachments..., great stuff. Regards the Electric Fan Test... Unless the Compressor Blades have a Ring of Stator-Vanes in front and behind them, then they won't be Compressing Anything, merely Displacing, and accelerating a Constant flow of Air moving back through the Disc. Actual Axial-Flow Compressor Blades function by kind of Scraping and squeezing the "bit of Air" which the Blade's Leading Edge cuts off from Airmass ahead of the Upstream Stator's Trailing Edge..., Off against and under the Downstream Stator Vane's Leading-Edge, with the Blade's pasding Trailing Edge... No Stators to "work against"..., with Each Blade generating a Leading and Trailing Compression/Decompression Wave Against EVERY Stator Vane in the Ring ; would mean that you'd be testing a Fan-Blades rather than Compressor Blades - and ideally the Inlet Guide-Vanes should be Adjustable, to check for Cyclic Stress-Concentrations across the entire range of actual operationally working Inlet-Vane Angles... And, to actuarially duplicate what a Working Blade experiences..., Would not one "Need" to have ALL the Blades on the Compressor Wheel, to be able to Replicate the environment of Turbulent Eddies being encountered by the Composite Leading-Edge - resulting from the "Compression-Scrapings" left in it's Path, from at least the Trailing Edge of the Blade ahead of the one to be tested... So, how about 2 Rows of Stators, 2 Composite Test Blades, each with a Metal Blade ahead of it on the Wheel, with the Pairs trying to be 180° across the Shaft from each other....? If the 12-blade Compressor 14:17 Array indeed uses 1,000 Hp of Twistiness at 7,000 RPM...(?) ; then 4 Blades between 2 Rings of Vanes should suck a "Mere" 333.3 Hp @ 7,000 RPM, and if your Grid runs at 50 Cycles/second then Electric Motors run happiest at 3,000 RPM, and 3,600 if the Grid has 60 Sine Waves per second.... You'll want a 2.35 or 1.95 to 1 Step-Up Gear Drive-Train between your 800 Hp Electric Motor. And at Half a Columbus worth of Wattzies (1492÷2 = 746...) At per each Horsie-Power of Twistiez, Then 799.2 Hp x 746 Watts = "Only" 596.2032 KillerWhats of Torque emerging from your Motor - Which might be 90% Efficient, at optimum RPM & Load. Which will be only happening at about 60% of it's Rated Output. So it might be Wisest to begin by Aiming at a 1,000 Hp Motor, Running at 60% Torque, To spin your Gear-Train which Delivers a Reliable 350 Hp or so at 7,000 RPM, To test a third of a Compressor Wheel worth of Blades... Half of which will be Composite Test Objects - Each with ut's Control In front of it on the Wheel... That strikes me as being a Shit-Ton of Electromechanical Engineering, But afterwards the Rig would still exist, ready to conduct further tests for years/decades to come. Burning the Fuel might be cheaper, and faster, Once, And it will cost the same in burnt Propane, every time after that. How many times will The nameless Client be wanting to Repeat the Test, on Similar - but different, "More Promising" Blade Pairs...? It appears to be a case of Do it Properly, or Burn (waste) Shitpots of Fuel Every time the Boffins have a sequential upgrade to their last Brainwave...(?) ! You'll work it out... Such is life, Have a good one... Stay safe. ;-p Ciao !

21 blades normally on a wheel, use every 7th position. i.e. 3 blades. Spinning would only identify creep or failure due to centripetal effect, not combined pressure action with centripetal. Methinks you will need some perforated disc behind the wheel to simulate (somewhat) compressor action by the blades. Maybe spare stators?

Agent Z, You are a “legend” in our A&P students’ community! Reference this experimental path, my vote is for: a. Populating the compressor with FULL (21 I guess) set of new blades (to get the relatively high "n" required for statistical analysis) at 125% of maximum operational RPM; for 1500 hours (slightly over two months 24/7) using an electrically driven motor. b. Stop experiment, remove and completely inspect 3 blade only at a time (7 blade apart) very thoroughly by all NDT techniques available and note deficiencies, then inspect another set of three blade the same way, and proceed until all 21 blades have been inspected (to get good data for statistical analysis on how to, and how many blades to inspect and how often to do it). c. If still serviceable, repopulate the compressor shafts with the FULL set of blades again; with the test compressor stage enclosed in vacuum sealed chamber and spun to produce 200% of design centrifugal load for 6 hours. d. Stop experiment and retest blades as in "b" above. e. If still serviceable, start again as set up for "c" above, run at 200% of design centrifugal load for one more hour; then without stopping the experiment, gradually reduce the vacuum (to reintroduce aerodynamic load) at steps of doubling such aerodynamic load in each stage of vacuum reduction. and remain at such load for one hour, until arriving at ambient pressure level. It will take some resources and cost to do it; but in the long run will arrive at practical implementation and certification quicker on the overall project path. In addition, you may be jumping ahead in development of test rigs and protocols for servicing and inspecting these blades once accepted into routine operation service. Al

Many a bug died that day

If you added a stator you would introduce minute pressure differences as the blades came together and passed. So (rough math) 24 blade fan at 6000 rpm=144,000 pressure changes per minute. MotoGP has banned the use of CF rims on race bikes because the of the unpredictable catastrophic failures that can occur on the wheels. There is a wheel, or there is shrapnel, there is no in-between. I am sure engineering can figure this out, but get lots of testing done.

Turning rain back into clouds in mere milliseconds... [HOP HOP HOP!]

Cool ill be back often again

Full Power for a HOUR on 3 test no problem is GREAT NEWS for me and everyone on the EARTH... i just hope the longevity will be FLAWLESS...

You could do with a partner in a very hot country, lots of people would enjoy the breeze coming out of that test rig.

Sweet video and great responses to some of these comments 😂

The described test rig sounds like a cool project. It is just for centrifugal loads w/o compression loads and only 4 blades it would certainly seem doable with a smallish electric motor. You could set up a live stream on your Patreon with a timer.

With the change in mass from having a full set these carbon comp blades bring any other advantages over the steel ones?

Dang... I hadn't considered the effect of a blade breaking and FOD'ing out the engine if you are standing down wind ("down stream"?). Does the shrapnel go directly to the rear, or could a blade fragment catch the air and deflect sideways? I think I'd stick to the control room and not tempt fate. 😄

i know that maybe its not applicable in this case, but ice/water ingression could be a problem with this carbon fiber blades?

That is both the beauty and the curse of carbon composites. While incredibly strong--you'd need a micrometer to check for any elongation--I tend to liken CC parts to bridge girders. They will do their job, and do it well, for dozens of years without fail. However as they age (mostly environmental impact, notably oxidation, heat fatigue and weather exposure) they can fail in the most strikingly catastrophic way without warning. In that moment, they lose a ton of energy though and the parts don't travel quite as freakishly shrapnel-esque like metallic components. The one saving grace so long as you're fifteen feet away for so. None of that is a knock on this project, rather a generalization of CC parts in hard use universal to the material. I wish I'd had high-speed camera footage during vibrational testing a few years back when I got a set of parts absolutely singing at 65K rpm and found the upper threshold of my bearings. Pow!

Any estimates on how much more efficient an engine would be with those lighter blades?

Hot stuff!❤️‍🔥 Who might take interest in this hmmmmm, GE maybe 🤔 Lockheed Martin maybe 🤔 S&S Turbines Maybe 🤔 and maybe PierCarlo and friends @ “ Starfighter’s Space “ as old Skool TV “ Laugh In” Would say “Very Interesting “🧐 OOPS I might have let the J79 out of the bag 💼 er cat 🐱.

🤗🤗🤗🤗🤗💯💯💯💯💯

i thought they already used composite blades in a gas turbine engine? GE90?

But do they pass the toughness standard? Pass the Bird strike test?

Hey J its been a while

what is the propane burn rate for one of these engines

What's the purpose of the CF fan blade on a ground running engine? Obv. weight in a flyer.

Here are my further thoughts, and I continue to maintain that the only truly representative test will be a field trials installation. However, I also maintain that a lot more testing than a few hours engine running in the test cell with even a full set of blades will be necessary before an operator agrees to a field trials exercise. So what can you do that's near 'representative', without tying up the test cell? I'm sorry, but just spinning a bladed stage 1 disc up to engine speed will not be 'representative'. The very fact that 50 to 200 HP might be sufficient to do the job should tell you that it's not. The composite blades need to be absorbing the power they would in the engine, which means they need to be subject to an equivalent of the engine installation, but without the rest of the engine. They need a front frame with its eight struts and a row of VSVs in front of them, together with a row of stage 1 vanes behind them. I imagine you and S&S Turbines have enough bits to build such an engine parts rig. However, it would probably need more than a couple of hundred HP to drive it, which starts to sound expensive, but far cheaper than engine running - and it frees up the test cell.

They need to do some testing to see what wear effects repeated starting and stopping does to the root. I would imagine the repeated loading and unloading of centripetal forces would be a lot harder on the resin than it would on steel.

11:18 If it is a 1000 hp fan, you won't test it at design speed with a 100 hp motor. You'll need 1200 hp or thereabouts. 1st law of thermodynamics.

A fiber plate will be as strong as metal. Until it gets a nic or microscopic scratch. Then it will shatter. Will also have terrible erosion qualities in sand or salty air

realizing we're still a way from aviation...are you allowed to comment on grain structure and how they go about 'forging' the blades? As shown narrow neck, potential different quick airfoil just seems 'wow'!

can you please pin a comment with a link to your explanation on the benefits of the new carbon fiber blades over the old metal ones?

🫂

To run a 1000hp turbine via a gearbox at max rpm, I suspect a 1000+hp electric motor would be needed. Unless you want to run it in a vacuum, unloaded.

I still think that these Carbon-fiber blades should be electroplated.. Some type of chrome-nickel (let the engineers figure that out).. 'cause I know they want these blades airborne.. well just for the heavy dust..