Just a small note b/c i'm a picky engineer. If you do (66,000 ft lb) x (3000 rev/ 60 sec) you get 3,300,000 ft lb/sec and since 1 hp = 550 ft lb/ sec, you get 6,000 hp, which is not right. Shaft Power is calculated as P = 2 x pi x rev/sec x Torque So if you multiply the 6000 hp x 2 pi you get about 37,700 hp which is a bit closer to that nominal rating of 34,800 hp. Thanks for clearing up the thermocouples thing for me! You explained it perfectly! Thanks for taking the time to do this Jay!
Subsonic aerodynamics is one of the most misunderstood subjects out there. This inlet was designed originally as part of a large turbofan aircraft engine. The bulletnose is so big that it forces any small particles of debris in the airstream to be deflected radially outwards toward the bypass duct and go through the fan. Only the much lighter "particles" of air can turn the corner around the bulging nose and make it into the fuel-burning core. So the airliner engine eats clean air.
A water wash is cool, because you can see the water going in the front. Water injection happens in the combustors, and there's no visible steam, so I don't know what you'd notice. The exhaust might change in appearance. The old jets would make a lot of black smoke when they used the water, but propane doesn't make soot like jet fuel.
Hey, you asked. The LP compressor is enlarged to become the fan. The first stage of it, anyway. Compressors and fans are devices that consume torque and produce air movement. Turbines are devices that consume (hot!) air movement and produce torque. Lot of people seem to not think of it that way. I'm always here to help 'em.
I know of a man who was one of the engineers on the Beech Starship. Not only did each propeller blade encounter extreme thermal shock when it rotated past the exhaust stacks for the engine, the resulting change in air density and velocity created a change in lift (thrust) over that section of the blade, setting in motion a mechanical oscillation and made the blades more prone to fatigue.
Well, the CFM56 is one of the engines I have not worked on, so I don't know exactly where anything is... but TIT is turbine inlet temperature, and is not usually directly measured because the temp is so high that thermocouples don't last very long in that location. ITT would be inter-turbine temperature, and is the temperature after the HP but before the LP turbine in this two-shaft engine.
Hello again JayZ, I have 3 new questions for you: 1) Hypothetically, what would happen if you would put 2 PT after each other. For example 2 of the one at 7:17. I know that it won't give you more power but why? 2) What is the difference between a 5 stage PT and a single stage PT (except of the obvoius stages)? How can simply one layer of blades be as effective as 5 of them? 3) How does a turbofan (like the CF6) get power to their generators? Where is that shaft? Greetings from Norway
It is not a destructive test, In an airliner engine, the water is flung outward by the fan, and almost none of it enters the core. So long as its a spray, like from 40 fire hoses, it increases the load on the fan, but does not damage it. A ton of water per minute would damage the core, but it does not get in there.
I wish people had at least basic knowledge before they start asking questions... I admire Your patience! That thing about power transformation was about the wery first thing i ever learned. But it´s still realy interesting when You explain it and show the real thing. (Sorry for my engish...)
if you ever go to Vegas check out the Carpenters Millwright Training Center to see the GE gas and steam industrial turbines. they take them apart weekly for training. Good job once again.
A very good question... for physicists and design engineers. Answer: I've thought about this subject, and wondered about it, but there is no way to test this, and honestly it is interesting but unnecessary information for those of us who put these things together. I suggest you research this subject further, and get back to us on it. Short version: I don't know.
this is great. It helps a lot to see this explained in a video, rather than just reading the info from the publication or manual. Happen to have any videos that are specific to a C-130J engine (AE2100D3)?
The LMS100 is a development of the LM2500 which has an entirely new combustor and a larger power turbine designed to extract as much power as possible out of the thrust of the gas producer.
With respect to the 5-stage aircraft version of a power turbine shown here, you'd mentioned they're no longer in use. What were they used to power (on aircraft); accessories, compressed air for start-up, etc.? Also, where would the tubojet that had this PT attached located (at or near the tail)?
Right, I understand. The 5252 actually appears when you combine the conversions in my formula. That is, the 550 ft lb/sec, 2 pi, and the 1/60 to convert from min to sec are all lumped together by 550 / (2 pi/60) = 5252. So your formula and my formula are identical...mine just used the definitions of each term to find the constant, 1/5252 which you multiply by at the end. So, both of our formulas are correct....your's is just a shortcut I had never realized before. Thanks XD
what is the air pressure to send in combusten chamber and what is the size of combusten chamber , compressing wheels and turbine wheels for producing 60 horse power. please
Thank you Jay for another great explanation! But once again I would like to ask you something. You've shown us a 5 stage aircraft PT. But what is it's use? Where in an aircraft do you need that amount of mechanical power? Most the power is used to accelerate the aircraft and only a minor amount is used to drive the generators, pumps etc. Or what do I get wrong? Maybe it has to do with the aircraft's PACKs?
Correct me if I'm wrong, but I think the LM2500 has the same core as the CF6 which is a high bypass turbofan engine. So, the LP compressor(s) would be used to turn the giant fan at the front of the engine.
The enlarged LPC of the engines use tremendous amounts of power to turn them... that's what the 5 stage turbine is for. Maybe I should have called it the LP turbine instead of an aircraft PT. That would have been more perfectly technically correct. If that's not clear, then please watch my videos on Turbojet or Turbofan, and also one called "Power Turbines: What are They?"
Am i right in thinking that scrap LP Turbine is off the CF6 that you took apart and its job on that engine is to drive that awesome big fan at the front of the engine?
No, and no. The gas generator turbine is designed to extract enough power from the exhaust stream to drive the compressor and the accessories, like the fuel and oil pumps. There is a lot of energy left over in the exhaust, and a jet engine uses a convergent nozzle to convert that energy into acceleration of the exhaust gases, which produces thrust. A power turbine can be place in the exhaust instead of a jet nozzle, and it turns all that energy into torque on a spinning shaft.
Hello Jey! is there any type of Temperature sensor which is able to operate in TIT ?And has any aerospace company already used temperature sensors in other part of turbines , like combusers?
Interesting. I always thought that turbo shaft engines had a direct connection throughout. I always wondered what kind of reduction box was used in let's say tractor pulling. Shows you how much I know about jet engines.
One way to help visualize it is to think of a very distant relative... the torque converter. Replace the ATF with air, and don't carry the analogy too far....
Other than at start up, where an electric or air starter is engaged, does a turbojet rotor assembly (compressor, shaft, turbine) generate torque perpendicular to the engine's axis that acts on the engine mounts?
Is the water injection because of NOx-regulation? How much does it affect the fuel-efficiency (thermal efficiency) of the engine? Does it drop by 1%? Less? More?
I watched one of your other videos where you test water injection and you said how many gallons it used, I think it works out to about 0,75-1,5 liters per second. To turn 1 liter of water into steam takes about 2MJ (at 100 C and 1 atm anyway), doing it every second means 2MW, that would be about 3% of the heat generated in the engine. If that is a loss or recovered downstream someone smarter than me will have to explain :-)
My educated guess would be that though you are losing combustion heat to vaporize the injected water, there will still be a small net benefit in efficiency because of the increased mass flow (energy flow) through the turbine (more turbine power, the purpose of water injection). This, of course is probably very much a function of how much water you are injecting as well. One would need to work the thermo to know for sure. While this is only a guess, in the case of steam injected gas turbines, the sole purpose is to increase efficiency while also augmenting power. This is easily possible since STIG systems utilize the waste heat from turbine exhaust to create the steam prior to injection into the combustor, as opposed to using the heat from within the combustor itself. This can increase thermal efficiency as much as 6-10% in some cases.
Yes, I made a typo. I meant the LP turbine(s). :-) A fan increases the pressure of a gas slightly and is mainly used to mobilize a gas. A compressor is capable of compressing a gas to a very high pressure. From an engineering perspective, a turbine is a device which takes the change in enthalpy (change in flow and internal energy) from the beginning of the first stage power turbine to the exit of the last stage and converts this change in enthalpy into useful shaft work which is what you said.
I saw a RR Trent1000 Water ingestion test @ 4.5 tons water per minute. It would be cool if you could do a Video on how a jet engine can take so much water and keep running. You mentioned once it would even increase power...
I don´t know if this question is allredy answeard, but i am curious about that type of blade that hawe integrated high temperature electronics in them.
Oh, but it is YOU, my good sir, being not completely accurate. If you examine the original question, it was asked about the present, as indicated by the use of the word "are". By changing the tense in your answer to the past, through the use of the word "used", you have lost your way, and are in error. Maybe we are both not accurate, because although Concorde never flies any more, I think I read somewhere that the russians still use the TU144. All that is mostly irrelevant anyway, because the spirit of the question was whether AB is used in industrial settings. Perhaps I over answered, and that was also a mistake, no?
I see now, sorry. I guess it's due to your own answer to Isaac not being time specific and that due to English not being my own mother language, I recognized "are used" as meaning "have been used" instead of "are being used".
I imagine that the answer here is an emphatic NO, as salt and mineral (normally present in sea water) deposition would quickly cause havoc in the combustion and HP turbine sections.
That’s interesting; I didn’t know turbines used water injection. That’s fairly common within the auto high performance industry, and extremely common with diesels. My rotary couldn’t live without W/I. 700 odd HP out of a 1.3l 13b-rew just isn’t possible without (barring expensive fuels) supplemental injection. (Either methanol, Water or a mix of the two)
sorry.i am indonesian, i m very interesting about jet engine. i have question about that. are the jet engine have limit when jet used in plane because air speed > from compresor speed? are we can transform jet engine to scramjet
Salam mas Naizar: Q1: No - the nozzle on the rear of the engine is used to accelerate air to an appropriate speed to match the needs of the aircraft - right up to Mach 3+ where speed is limited by other factors. Q2: Jet engines are very carefully engineered to their purpose. Kayaknya lebih mudah mulai dari nol, daripada konversi begitu.
No, it was my fault. I was a bit confused of thinking only about driving a mechanical load (pumps, generators etc.) and I totally forgot the FAN in an aircraft engine. Unfortunately I figured it out after hitting the "post" button... :-) But anyway, thank you for the video and the comment!
intersting. If you would measure the amount of fuel is used in normal operation (no blocked fuel nozle) and compare it to the amount that is used in abnormal operation, then you could figure out, that something is wrong, without reading out the temperature-sensors? Are these information a captured by the electronics? Ok, the fuel consuption depends on a lot of more factors, like air, water in the air, etc.... but anyways, like you professional videos!
That's because, you used the wrong formula. If you take the simple route, and use the "trades math" ( gaaaack!) equation, then 66,000 X 3,000 /5252 = 37,700 This formula is basic, crude, and in every handbook out there, even in a recent issue of Cycle World... they even explain where the 5252 constant comes from. So please, nobody needs to explain it here.
Just a small note b/c i'm a picky engineer. If you do (66,000 ft lb) x (3000 rev/ 60 sec) you get 3,300,000 ft lb/sec and since 1 hp = 550 ft lb/ sec, you get 6,000 hp, which is not right. Shaft Power is calculated as P = 2 x pi x rev/sec x Torque So if you multiply the 6000 hp x 2 pi you get about 37,700 hp which is a bit closer to that nominal rating of 34,800 hp.
Thanks for clearing up the thermocouples thing for me! You explained it perfectly! Thanks for taking the time to do this Jay!
Thanks for the thermocouple explanation. Another nugget of information to file away in the bank. Great stuff as always.
I feel so privileged to share this lesson with just 950 classmates by now. I hope it gets more though!
Subsonic aerodynamics is one of the most misunderstood subjects out there.
This inlet was designed originally as part of a large turbofan aircraft engine.
The bulletnose is so big that it forces any small particles of debris in the airstream to be deflected radially outwards toward the bypass duct and go through the fan.
Only the much lighter "particles" of air can turn the corner around the bulging nose and make it into the fuel-burning core. So the airliner engine eats clean air.
A water wash is cool, because you can see the water going in the front.
Water injection happens in the combustors, and there's no visible steam, so I don't know what you'd notice. The exhaust might change in appearance.
The old jets would make a lot of black smoke when they used the water, but propane doesn't make soot like jet fuel.
This is great, now I understand how power is produced from the jet engine.
Hey, you asked. The LP compressor is enlarged to become the fan. The first stage of it, anyway.
Compressors and fans are devices that consume torque and produce air movement.
Turbines are devices that consume (hot!) air movement and produce torque.
Lot of people seem to not think of it that way. I'm always here to help 'em.
Once again agentjayz fed my mind, satisfied my curiosity, and entertained me for 20 minutes! Great videos
Fantastic explanations! I'm glad you take the time to explain this stuff clearly.
I know of a man who was one of the engineers on the Beech Starship. Not only did each propeller blade encounter extreme thermal shock when it rotated past the exhaust stacks for the engine, the resulting change in air density and velocity created a change in lift (thrust) over that section of the blade, setting in motion a mechanical oscillation and made the blades more prone to fatigue.
Great explanation on temp distribution and thermocouples .Thank you Jay.
Well, the CFM56 is one of the engines I have not worked on, so I don't know exactly where anything is... but TIT is turbine inlet temperature, and is not usually directly measured because the temp is so high that thermocouples don't last very long in that location. ITT would be inter-turbine temperature, and is the temperature after the HP but before the LP turbine in this two-shaft engine.
each time i look one of your video, it remind me that youtube is cool because of people like you. Thanks!
Great explanation on Thermocouples, Thanks JayZ
Your channel deserves much more followers!
It´s Guys like You that should hawe those 10+ milions of followers!
Hello again JayZ, I have 3 new questions for you: 1) Hypothetically, what would happen if you would put 2 PT after each other. For example 2 of the one at 7:17. I know that it won't give you more power but why? 2) What is the difference between a 5 stage PT and a single stage PT (except of the obvoius stages)? How can simply one layer of blades be as effective as 5 of them? 3) How does a turbofan (like the CF6) get power to their generators? Where is that shaft? Greetings from Norway
It is not a destructive test, In an airliner engine, the water is flung outward by the fan, and almost none of it enters the core. So long as its a spray, like from 40 fire hoses, it increases the load on the fan, but does not damage it.
A ton of water per minute would damage the core, but it does not get in there.
I wish people had at least basic knowledge before they start asking questions...
I admire Your patience!
That thing about power transformation was about the wery first thing i ever learned.
But it´s still realy interesting when You explain it and show the real thing.
(Sorry for my engish...)
... I meant to do that, but I wonder if that will soon be seen as copyright infringement.
if you ever go to Vegas check out the Carpenters Millwright Training Center to see the GE gas and steam industrial turbines. they take them apart weekly for training.
Good job once again.
many thanks high respects to you for taking the time to do this! I love it.
Perfectly explained Jay!
A very good question... for physicists and design engineers. Answer: I've thought about this subject, and wondered about it, but there is no way to test this, and honestly it is interesting but unnecessary information for those of us who put these things together.
I suggest you research this subject further, and get back to us on it.
Short version: I don't know.
this is great. It helps a lot to see this explained in a video, rather than just reading the info from the publication or manual. Happen to have any videos that are specific to a C-130J engine (AE2100D3)?
Helped a lot. Loads of it. Thanks. Brilliant
The water lowers combustion temp... by turning to steam, so even mre fuel can be added, making more steam. Both things help boost power output
The LMS100 is a development of the LM2500 which has an entirely new combustor and a larger power turbine designed to extract as much power as possible out of the thrust of the gas producer.
And thank you for time and "Hands On" explanation.
With respect to the 5-stage aircraft version of a power turbine shown here, you'd mentioned they're no longer in use. What were they used to power (on aircraft); accessories, compressed air for start-up, etc.? Also, where would the tubojet that had this PT attached located (at or near the tail)?
These videos should be mandatory in pilot training/ A&P school!
Not if they are illegally copied, denying the view count to the creator...!
@@AgentJayZ I meant viewed individually as an assignment... great work keep it up!
It's called a compressor inlet temperature sensor, Or CIT sensor.
Right, I understand. The 5252 actually appears when you combine the conversions in my formula. That is, the 550 ft lb/sec, 2 pi, and the 1/60 to convert from min to sec are all lumped together by 550 / (2 pi/60) = 5252. So your formula and my formula are identical...mine just used the definitions of each term to find the constant, 1/5252 which you multiply by at the end. So, both of our formulas are correct....your's is just a shortcut I had never realized before. Thanks XD
what is the air pressure to send in combusten chamber and what is the size of combusten chamber , compressing wheels and turbine wheels for producing 60 horse power. please
Thank you Jay for another great explanation! But once again I would like to ask you something. You've shown us a 5 stage aircraft PT. But what is it's use? Where in an aircraft do you need that amount of mechanical power? Most the power is used to accelerate the aircraft and only a minor amount is used to drive the generators, pumps etc. Or what do I get wrong? Maybe it has to do with the aircraft's PACKs?
Correct me if I'm wrong, but I think the LM2500 has the same core as the CF6 which is a high bypass turbofan engine. So, the LP compressor(s) would be used to turn the giant fan at the front of the engine.
The enlarged LPC of the engines use tremendous amounts of power to turn them... that's what the 5 stage turbine is for. Maybe I should have called it the LP turbine instead of an aircraft PT. That would have been more perfectly technically correct.
If that's not clear, then please watch my videos on Turbojet or Turbofan, and also one called "Power Turbines: What are They?"
Am i right in thinking that scrap LP Turbine is off the CF6 that you took apart and its job on that engine is to drive that awesome big fan at the front of the engine?
Watching now. Thanks again man. Great videos.
No, and no. The gas generator turbine is designed to extract enough power from the exhaust stream to drive the compressor and the accessories, like the fuel and oil pumps. There is a lot of energy left over in the exhaust, and a jet engine uses a convergent nozzle to convert that energy into acceleration of the exhaust gases, which produces thrust. A power turbine can be place in the exhaust instead of a jet nozzle, and it turns all that energy into torque on a spinning shaft.
Rad! I had no idea water injection was still being used on gas turbines. Any plans to film a water-injected test run?
Hello Jey! is there any type of Temperature sensor which is able to operate in TIT ?And has any aerospace company already used temperature sensors in other part of turbines , like combusers?
Interesting. I always thought that turbo shaft engines had a direct connection throughout. I always wondered what kind of reduction box was used in let's say tractor pulling. Shows you how much I know about jet engines.
One way to help visualize it is to think of a very distant relative... the torque converter.
Replace the ATF with air, and don't carry the analogy too far....
I'll bet you'd enjoy watching my video" turbojet or turbofan"...
Also take a look at
"Power turbines: what are they?"
Other than at start up, where an electric or air starter is engaged, does a turbojet rotor assembly (compressor, shaft, turbine) generate torque perpendicular to the engine's axis that acts on the engine mounts?
Thank you Jay from Power-Tech Engineers
Can you just take torque straight off the back of the engine without the Power turbine or is there too much energy lost?
Is the water injection because of NOx-regulation? How much does it affect the fuel-efficiency (thermal efficiency) of the engine? Does it drop by 1%? Less? More?
This operator uses it to maximize power, and reduce NOx. I don't know the effect on efficiency.
I watched one of your other videos where you test water injection and you said how many gallons it used, I think it works out to about 0,75-1,5 liters per second. To turn 1 liter of water into steam takes about 2MJ (at 100 C and 1 atm anyway), doing it every second means 2MW, that would be about 3% of the heat generated in the engine. If that is a loss or recovered downstream someone smarter than me will have to explain :-)
My educated guess would be that though you are losing combustion heat to vaporize the injected water, there will still be a small net benefit in efficiency because of the increased mass flow (energy flow) through the turbine (more turbine power, the purpose of water injection). This, of course is probably very much a function of how much water you are injecting as well. One would need to work the thermo to know for sure. While this is only a guess, in the case of steam injected gas turbines, the sole purpose is to increase efficiency while also augmenting power. This is easily possible since STIG systems utilize the waste heat from turbine exhaust to create the steam prior to injection into the combustor, as opposed to using the heat from within the combustor itself. This can increase thermal efficiency as much as 6-10% in some cases.
Yes, I made a typo. I meant the LP turbine(s). :-) A fan increases the pressure of a gas slightly and is mainly used to mobilize a gas. A compressor is capable of compressing a gas to a very high pressure. From an engineering perspective, a turbine is a device which takes the change in enthalpy (change in flow and internal energy) from the beginning of the first stage power turbine to the exit of the last stage and converts this change in enthalpy into useful shaft work which is what you said.
I saw a RR Trent1000 Water ingestion test @ 4.5 tons water per minute. It would be cool if you could do a Video on how a jet engine can take so much water and keep running. You mentioned once it would even increase power...
She's around, but she keeps a low profile. She's more of a lounge cat that lives in a shop.
Thanks to you !
I don´t know if this question is allredy answeard, but i am curious about that type of blade that hawe integrated high temperature electronics in them.
what airplane/helicopter would have used that engine with the aerospace power turbine??
I'd like to know which aircraft used that LM2500 aviation power turbine.
The EGT sensing elements are immersed in the LPT nozzle stage 2.
Once again..thanks for this video ! :D
thx.very useful video as other ones.
I really should have called it the LP turbine, 'cause that's what it is... of a CF6-6 turbofan engine
Thanks from Australia
show us from where the cooling air comes from to cool the turbine blade?
why is the nose cone so big? does it not inhibit airflow/intake?
Are afterburners for aircraft only? Or are they used in industrial engines as well?
+Isaac Lubow Only military fighter jet engines.
You're not entirely accurate; the supersonic passenger jet planes Tupolev 144 and Concorde used afterburners too.
Oh, but it is YOU, my good sir, being not completely accurate. If you examine the original question, it was asked about the present, as indicated by the use of the word "are".
By changing the tense in your answer to the past, through the use of the word "used", you have lost your way, and are in error.
Maybe we are both not accurate, because although Concorde never flies any more, I think I read somewhere that the russians still use the TU144.
All that is mostly irrelevant anyway, because the spirit of the question was whether AB is used in industrial settings. Perhaps I over answered, and that was also a mistake, no?
I see now, sorry. I guess it's due to your own answer to Isaac not being time specific and that due to English not being my own mother language, I recognized "are used" as meaning "have been used" instead of "are being used".
Apollorion ...So long as we are all having fun. That's the most important thing.
ah i see :), very interesting to know it also is designed so to prevent big particles/debree from getting in the center of the engine :)
Is it possible to use seawater to increase the power (or efficiency) of a gas turbine driven boat?
I imagine that the answer here is an emphatic NO, as salt and mineral (normally present in sea water) deposition would quickly cause havoc in the combustion and HP turbine sections.
Do you donate scrappable engines/engine units to schools? I'd have loved to have something like that in my primary school.
We have hardware we could donate.
You pick, you pack, you ship.
thanks..
great vid as always!
Thanks for the explanation, again. Simplified, it's like a small wind generator that has a jet engine in front of it. Zero connection except the wind.
That’s interesting; I didn’t know turbines used water injection. That’s fairly common within the auto high performance industry, and extremely common with diesels. My rotary couldn’t live without W/I. 700 odd HP out of a 1.3l 13b-rew just isn’t possible without (barring expensive fuels) supplemental injection. (Either methanol, Water or a mix of the two)
Yes you are...
Gotta love turbine engines, IMO they are the best :P
sorry.i am indonesian,
i m very interesting about jet engine.
i have question about that.
are the jet engine have limit when jet used in plane because air speed > from compresor speed?
are we can transform jet engine to scramjet
sorry i m not good in english
Salam mas Naizar:
Q1: No - the nozzle on the rear of the engine is used to accelerate air to an appropriate speed to match the needs of the aircraft - right up to Mach 3+ where speed is limited by other factors.
Q2: Jet engines are very carefully engineered to their purpose. Kayaknya lebih mudah mulai dari nol, daripada konversi begitu.
In terms of the temp, check it out here on utube. There's a test somewhere, (NOT JayZ) where they get a hot spot. Not good.
No, it was my fault. I was a bit confused of thinking only about driving a mechanical load (pumps, generators etc.) and I totally forgot the FAN in an aircraft engine. Unfortunately I figured it out after hitting the "post" button... :-)
But anyway, thank you for the video and the comment!
the best part of this video was the canadian flag in the background!
"that something is wrong" is not the same as excessive EGT spread.
a water ingestion test is a destructive testing that manufacturers often use to pass a certification process.
intersting. If you would measure the amount of fuel is used in normal operation (no blocked fuel nozle) and compare it to the amount that is used in abnormal operation, then you could figure out, that something is wrong, without reading out the temperature-sensors? Are these information a captured by the electronics?
Ok, the fuel consuption depends on a lot of more factors, like air, water in the air, etc....
but anyways, like you professional videos!
So what about a turboprop. Same concept?
Good one, understand
Ok, I totally forgot the FAN that is driven by the LP turbine - a power turbine. :-)
Will do.
:-)
Yeh on you!
That's because, you used the wrong formula.
If you take the simple route, and use the "trades math" ( gaaaack!) equation, then
66,000 X 3,000 /5252 = 37,700
This formula is basic, crude, and in every handbook out there, even in a recent issue of Cycle World... they even explain where the 5252 constant comes from.
So please, nobody needs to explain it here.
Tnks
Thx
I'll bet you'd enjoy watching my video" turbojet or turbofan"...
now a days....you never know!
Yeah, I figured it out by myself. But thanks!
Tanks so mache