Which way do the Jet Engines rotate? And WHY?!

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Have you ever wondered in what direction the jet engines are turning and why? Do both engines turn the same way or do they turn opposite to each-other and what is a Critical engine?
In todays episode I will get into the nitty/gritty regarding engine rotation. I will be speaking about propellers, P-factor, Harrier Jump-jets and much much more.
Make sure you come in and tell me what you thought about the episode in the Mentour Aviation app after you watched it. Thats where I hang out with you guys and answer the questions that might come up.
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i want to say a huge thank you to the channels that were featured in todays video. To see the full, AWESOME, videos, use the links below 👇🏻
Dirk-Jan Kraan (Engine spooling up)
• Video
Aeroiki (Aircraft veering off runway)
• Twin Beech Runs off Ru...
Aviation Buzzword (Helicopter with tail rotor failure)
• Helicopter Anti-Torque...
ElessarDunedain (Gyroscope)
• Gyroscope suitcase fun
BoxerLHD4 (Harrier landing and TO)
• Harrier Vertical Landi...
Patrizio Migliola (b737 pushback and engine start)
• NORWEGIAN B737-800 - P...
Mr.I.fix.planes (Trent 1000 startup sequence)
• Boeing 787-8 Trent 100...

[@BryanDorr]

Takeoff, rapid descent, rolls, spins, short landings, CRM, communicating, crew rests: all the things I have learned just from watching Patxi in this episode!

[@johnanderson9494]

That dog knows much more about aviation than other dogs.

[@keith2964]

No bones about it!!

[@Prems66]

lol

[@jimbob036]

Poor guy, he's being ignored by his companion, who's talking to the camera, not him!

[@nwazuemunachi6339]

LOL..Very funny.😅😅

[@foreverpinkf.7603]

And it wants attention.

[@shkuperus]

Great video, my instructor always said: forget what you learned about critical engines, the only real critical engine is the one still running after an engine failure :D

[@rob8529]

Right on!

[@badlandskid]

Kinda fits in with “Take off is optional, landing is mandatory!”

[@dewiz9596]

The second engine always gets you to the scene of the crash. . .

[@HernandoEUrrea]

Where did you learn to flight ????

[@HernandoEUrrea]

What makes jet engines not have P-Factor is the ducted fan that parallel the flow of air to the duct before meeting the fan. The stators (or mixer exhaust in small engines) straighten the flow and avoid the spiraling slipstream behind the fan. also in the jet engines the fan and low pressure turbines rotate in one direction and the high pressure compresor and the high pressure turbine in the other dirección diminishing Torque effect and gyroscopic effect. I am a CFI CFII MEI AGI and ATP with several type ratings including propeller driven engines and jet engines. And also have all the ICAO Licenses. So twin engine Jets do not have critical engine, but three engine aircraft and four engine jet aircraft, yes, either number one (and three in 3 engine aircraft) or four engine.

[@crisrose521]

Back in 2019 at LGA as I was sitting at the bar , I actually walked up to a pilot and asked him this very question . He said they both turn the same direction and when I asked if reverse thrust was possible during flight he mentioned WOW to me . I learned more after that one drink than I could have ever imagined 😊 Great channel , thank you

[@MRBROWSER2012]

That is fascinating. I never knew jet engines rotate the same direction and have always assumed they rotate in opposite directions to balance the torque...I was wrong all that time. Thanks for another great explanation.

[@AntonioCunningham]

You know you've subscribe to the right channel when they're answering questions you didn't know you wanted answered. Thank you Peter😊

[@EveryTipeOfVideo]

Hahaha! I agree 👍

[@ziggy2shus624]

Gyroscopic effects were apparently quite large in WW1 fighter aircraft that had engines like the Rhone and Gnome Rotary. In a rotary engine the entire engine rotates and with the little WW1 planes being very light and the very heavy engine rotating caused problems. The Sopwith Camel needed left rudder for both left and right turns and trainee pilots were told not to make turns below 1,000 ft, to give them time to recover in case they messed up.(See Wikipedia - Rotary Engines - WW1)

[@Lucky-qe3iq]

So which way does your dog rotate around your couch?

[@AmaroqStarwind]

Both ways!

[@curvebal]

Very good explanation of torque and gyroscopic effect for non science viewers. The fact that you can explain these concepts in simple terms is the sign of a good teacher. I bet you enjoy challenges, explain the Coriolis Effect on long distance plane travel. Great job!

[@hangglider1979]

Fascinating stuff. So much more to flying than I could have imagined.

[@michaellochner9145]

The best analogy I gave for torque during my flight instructor days was using a drill and the screw getting stuck. The screw and motor is rotating clockwise but when the screw gets stuck, the drill moves the opposite direction. It’s always an easy way to visualize torque

[@Twobarpsi]

Excellent analogy!

[@Cimanator]

See what you did there with the coloured cushions...

[@Azmythometre]

Haha, I didn't notice that

[@cloudk2088]

Just wanted to say thanks for sharing all your knowledge with us. I find all these small details very interesting.

[@mattdombrowski8435]

fun fact: the sopwith camel (and other pre-WWI and WWI aircraft) had rotary engines; imagine a car's engine but the pistons and engine casing are the ones rotating rapidly instead of the crank shaft. This means that the engines had enough rotating mass for gyroscopic possession to become a significant factor. This caused trouble for pilots, especially with landings.

[@MentourPilot]

Correct!!

[@cr10001]

@Kevin Counihan The gyroscopic effect was reputedly the cause of problems with rotary-powered WW1 fighters like the Camel. But I believe the problem with later World War 2 fighters was not so much gyroscopic, it was simply the massive torque reaction from the huge prop turned by a 2000-hp engine, especially if the throttle was opened too fast at a low airspeed. Just looking at the props on a p51 or a Typhoon you can imagine the effect.

[@brentboswell1294]

@@cr10001 the F4U Corsair was the worst offender in that department. The Marine Corps actually produced a film of a simulated carrier go-around (at altitude) to show pilots why hammering the throttle was a bad idea!

[@frostycab]

Yet another great video clearing up so many questions. Regarding the direction of rotation on jet engines, I have heard of just one example where the direction of rotation actually DID matter on an aircraft, and that was Concorde, where I believe they would hold the #4 engine at a lower N1 during the first portion of the takeoff roll to prevent the vortexes off the wing leading edge interfering with the engine. This wasn't a concern for the #1 engine as the vortexes would rotate the same way as the engine.

[@makecba]

where did you get this from? I don't think that's right, every Concorde video I've seen shows all four 593s running at full reheat on takeoff.

[@sharoncassell9358]

Vortices is plural of vortex.

[@jimbob036]

Re the apparent change in direction on the fan due to camera frame rate, I first remember noticing this on old westerns when I was a kid. The spoked wheels on the horse-drawn wagons often looked as if they were rotating in the wrong direction.

[@pau_casajuana]

Last year I had the chance to see a real Harrier in action during an airshow in Lleida. What a spectacular aircraft.

[@MrRexquando]

That was a ground breaker! Wonder why it took so long for version 2 (F35B)?

[@dihydrogenmonoxid1337]

Really appreciate your hella good and informative content. It is such a big motivation for me. Thanks! Keep it going :)

[@MrBruinman86]

Things I've always wondered. Nice to have an easy way to find out those very questions.

[@DroneMee]

Great content as always! The engines in the F-22 and F-35 have counter rotating HP and LP and I didn't think of why until this video. Gyroscopic effect!

[@gpmenvironmental4569]

Very good and informative video. I had never thoughts of this. Thank you

[@bencroll3860]

Great content in this video! Keep up the awesome work.

[@leo7779x]

Quad jet engine aircraft also have critical engines. They are the outer ones, because if you lose one of them the other one will have a way bigger arm with only the inner one working on the other side.

[@buddyclem7328]

*critical That's interesting, but it makes sense the way you explained it.

[@dpg0jod]

Having a US nuclear Navy background & a career in the commercial nuclear generating industry, I am particularly grateful for the technical content of your videos. The fact that you are an active commercial pilot who has achieved the pinnacle as the most senior of instructors and check pilots only enhances the credibility your four stripes convey. I realize.your audience is likely comprised of flight students, aviators & aviation enthusiasts, but my aviating experience consists of being a largely ignorant passenger. I did have an occasion on a corporate jet to sit in the cockpit jump seat. I had a million questions but was loathe to ask as I felt in impolite to interrupt the pilots while airborne unless invited to. All that to say, of all the aviation videos I have watched from multiple contributors, yours is head & shoulders above the rest. The content is the most varied, from the more technical or serious such as accidents, to lighter, more informative. I don’t know how you find the time to maintain your professional/personal lives and put together such professional & coherent content with a great personality & engaging presentation skills. The dogs are a nice touch. Perhaps the income from your various social media endeavors may some day manage to pry you away from doing what you clearly love to devote more time to your personal life & perhaps develop even more content? Maybe even purchase a very sporty private aircraft?

[@Bismuth69]

Thanks for an informative video. Had just listened to ATC from KBLI tower, where a Piper Comanche went off the runway due to inconsistent engine power, the reason pretty much explained in this video.

[@RaferJeffersonIII]

You have a furry mass rotating around your couch.

[@raven1378]

this.... holy shit this lol. i almost tried to come up with a snarky comment but you beat me

[@acrossthissky8406]

XD

[@pudmina]

@Harry M - ROFL ... A canine version of the Energizer Bunny :)

[@pudmina]

@Harry M - Not sure, but if you use any of the available orifices you're bound to have a very unhappy puppy on your hands. UFO is very appropriate ... I've watched several other of his videos where that furball spent all of its time trying to get a certain pilot's undivided attention :)

[@RaferJeffersonIII]

They call them “turbofan” engines but in reality there are 100,000 of these in sequence rotating the blades. That’s not 300kg of fuel, it’s Winalot

[@longdongsilver4719]

As usual: clear and precise. Thank you for the big amount of info you share.

[@FSstefan7]

Thanks. Awesome info.

[@adamkowalczyk3474]

Thanks Mentour, great video!

[@rizdzwan7]

Thumbs up 👍 captain....great information.

[@tom7601]

My dad flew B-17s and B-29s during the war. It used to drive him crazy to be in a piston airliner when the flight engineer failed to keep the engines in sync. I guess it was keeping the props in sync.

[@timw2498]

The updated app looks great!

[@jimrobertson6959]

I found this to be the most interesting Mentour Pilot video to date. While I knew and understood the gyroscopic and torque forces, I had never engaged my brain on the issues of the momentum arm. Really interesting stuff! What I really would like to know is how do engine and aircraft manufactures arrange for the coupling of the engines to the wings. I cannot imagine that all the coupling points are placed symmetrically inline along the chord of the wing so there would at least have to be left and right wing fittings. Just, in general, I wonder about the couplings of the engines to the wing and would love to see a documentary on how this is done.

[@MentourPilot]

Great! Now watch my engine failure after takeoff video and you will understand more. See you in the app!

[@JG-pw5cr]

Thank you sir for doing a great job at answering all of these questions in such a clear manner. I learn random things on youtube all the time and it's great to learn.

[@sebs9511]

You made everything very clear to understand. Great explanation! Thank you and safe flights!

[@EveryTipeOfVideo]

Smash that like button on this video because this video had to be re-recorded due to Audio issues 😔 Show Petter how much you appreciate it!!

[@washx2k755]

who told you?

[@EveryTipeOfVideo]

@@washx2k755 Petter

[@SteeringWheelOperator]

@@EveryTipeOfVideo Crap, I can only smash it once. If I smash it twice, it goes back 1. How to fix that?

[@EveryTipeOfVideo]

@@SteeringWheelOperator Just smash it once and it will be alright

[@BrianThorstad]

I did a 1 hour training video at work once (w audience) to find it did not record...went to my office and did it again. Been there, did that (for the love of my craft...just like Peter who we all love). (Be a Patrean) -Patrean Brian

[@erwickdsouza]

As always, super informative. Thank you MP! Also, your dog stole this show. Always keep him in your videos.

[@sefutho]

Very informative. Thank you.

[@artysanmobile]

Excellent video! Thanks.

[@Lloyd2605]

Awesome video yet again mate.!

[@MaltaMcMurchy]

Thank you for sharing this wonderful explanation! 👍

[@jetblackjoy]

Thank you for a clear explanation!

[@Akula114]

It takes a person with deep knowledge of a subject and the confidence in that knowledge to be able to clearly explain it to others. For an example, see any Mentour videos!

[@topfelya]

Great educational video ! Lots of interesting information.

[@DCBpower]

Great videos, superb music, and of course, love the matching dog. 👍

[@MrRexquando]

As always a great video. f35B uses one engine that is not counter-rotating. Trent 900 has counter rotating spools for fuel efficiency (not gyroscopic reasons). Most of this NOT being factor is because the majority of the mass is on the shaft or closer to the center (mass moment of inertia) This is why a gyroscope has a lot of mass at the outer edge vs spindly shaft. In turbo props we dilute this by the "p" angle of the prop disk.

[@vincentlang5658]

Very informative. Thx.

[@miked51]

Not only are you my go to for anything and everything related to aviation and avionics but the the most fantastic KZbinr. Also, your Dog is the cutest animal in the world. Such a character. Keep up the great work. I look forward to all your videos and your app is awesome. Thank you and as always, have a fantastic day.

[@Denvermorgan2000]

Thanks for a great explanation.

[@rydergw]

Your little dog is SO beautiful !

[@MentourPilot]

He is a lovely little pup.

[@katmen24]

@@MentourPilot great poodle, my poodle Max is also huge fan of aviation

[@dosetti]

Yes, very interesting and you were able to explain it very clearly. Thanks!

[@MentourPilot]

Thank you! I’m happy you liked it! See you in the app!

[@PollockKenrick]

Lol I love the NAV Lights couch pillows...smart! 👍🏽

[@slam854]

I failed your question about rotation though I Brilliantly passed on engine internals and fan ducting. Enjoyment & education from your channel is #1.

[@Twobarpsi]

Excellent video!!

[@tobys_transport_videos]

Puppy has a rotating effect! He needs his wings!!! LOL!

[@Seventh7Art]

Please, make a video about N1 and N2 rpm. What is the speed of the air, in front and behind the jet engine?

[@PlanesAndGames732]

Up

[@ahmadtheaviationlover1937]

ΓΕΩΡΓΙΟΣ n1 is the big primary rotary fan in the middle of the engine. N2 is the compressor blades in the aft section of the engine. Their job is to compress the air but the n1 is the one that sucks the air in. N1 starts first because the air being sucked is the main rotary fan then the compressor blades which are linked on the bypass shaft (n2 starts up next)

[@stathisbikos6563]

@@ahmadtheaviationlover1937 You are confusing your nomenclature my friend. N1 Is the speed of the Fan shaft (the inner-most shaft, that has the fan (forward) as well as the low speed turbine (aft) attached to it) N2 is the speed of the engine core shaft that has the compressor on the FORWARD, and the high speed turbine on the AFT of the engine. (both shafts run through the length of the engine and have blades both aft and forward) Three-shaft turbofans also exist that have separate intermediate and high pressure shafts (plus the low pressure fan shaft). These engines also have a N3 value. When starting the engine ONLY the high pressure (N2) shaft (for a 2 shaft engine) is started by the starter (which is powered by APU bleed air) When N2 reaches roughly 20-25% N2max the fuel is introduced and the engine starts (ignition switches have been set to "start" earlier still) The low speed shafts IS NOT energized by the starter directly, it starts moving as the air leaving the engine core starts to turn the low pressure turbine.

[@kenbellchambers4577]

Brilliant question. Does anyone know the pressures involved with a forward speed of 1,000 kms per hr. What is the engine pressure?

[@deep.space.12]

@@kenbellchambers4577 My math is probably wrong, but I guess you can multiply the Engine Pressure Ratio (roughly 30-50) with the dynamic pressure of air at 1000km/h (I think that's 6 times sea level pressure) to get engine pressure. (Or do I need to add atmospheric pressure to the dynamic pressure?)

[@friendme1032]

You have a great gift to communicate, teach and speak very clearly and nicely. You should teach aviation class at the university😊 I enjoy your smart and communicative videos. Best

[@PhilGz]

Always great videos, thank you. :-)

[@RVNspotting]

Intressant! Trevlig helg!

[@Gurer_Hizel]

Thanks, i like learning new things about aviation.

[@engrpas]

The captain refers to “momentum arm” if I’m hearing it correctly. The proper terminology is “moment arm” because the rotational force is called “moment” not momentum. Momentum is a completely different physical phenomenon. In fact, moment is the same concept as torque - torque is generally used when dealing with shafts of machines, while moment is used when assemblies, like airplanes, are subjected to rotational forces. Great video, though, as usual!

[@mytech6779]

Torque is the rotational stress created in an item as a result of differing moments. That is two opposing moments on opposite ends of a shaft create torque, one unopposed moment simply causes rotation, two equal opposing moments acting on the same end of a shaft do not create torque or rotation. There is also a moment of inertia and moment of area to deal with beam cross sections, which have a similar basis in the effective length of lever arms, although it is applied to bending strength and stiffness and there is no obvious rotation.

[@engrpas]

@@mytech6779 Thanks, I'm quite familiar with torque, moment, momentum, moment of inertia and moment of area - I spent my near-50 year engineering career designing rotating machinery. The point of my post was simply to note that the captain kept saying "momentum arm" instead of "moment arm" when talking about asymmetric thrust, that is, the distance of the engine centerline from the fuselage centerline, and I was simply correcting his terminology.

[@vivekbarchha]

I was bit confused about that thanks for the clarification I remember in school learning about "principal of Moments"

[@ynot6473]

we'll let him off though, as English is not his first language.

[@aaronaustrie]

Nice content!!

[@outabeat]

I'm going to share this video with my son who is in college majoring in engineering. He was talking about this recently from one of his physics classes. Thanks for the video.

[@esesilva6990]

Thank you for the video ,

[@SimonSNB]

Dog is man's best friend and we have Petter and Patxi to prove it 😉

[@BlueZirnitra]

Did you know you can buy a pillow or a cup with Patxi on it?

[@river1403]

Ben McCann wait really?

[@rogerstone3068]

Love the way the dog starts rotating as you're talking about torque and gyroscopes: live furry demo.

[@leandrocarvalho8981]

Pilot Mentour! Thanks for more one Nice and Important explanation! Keep the blue sky up...Hugs

[@aaronaustrie]

Interesting topic!

[@smtmsjacolyn6699]

Your explanations are so distinct and clear, a student under your guidance will sure end up with Captaincy. Great video very versatile and very informative. Jacolyn (Srilanka).

[@ihorkohut7290]

Like in advance. Haven't seen yet. Now starting to watch :)

[@airfoxtrot2006]

Great video Mentour i enjoyed it, have a good weekend my friend. Im @captainfox on the Mentour App.

[@driptabarman957]

I just love your videos Mentour. Please make a video about Non Precision Approach. I dont think you made a video regarding that topic.

[@chrismorton966]

Great explanation! Only slight inconsistency I have noticed in this and other videos when you are animating jet engines with your fingers, you counterrotate your fingers instead of rotating them the same direction as you describe jet engines do.

[@IvanIvanov-ve6ti]

- With me so far? - No. - Good.

[@MrSvenovitch]

exactly, this is annoying. the video is not interactive but he doesn't seem to realize this. accent also not helping. do not pronounce english words in nordic style.

[@VoidSixx]

@@MrSvenovitch His English is fantastic, and his accent is pretty clear and easy to understand.

[@dokzero5]

@@MrSvenovitch He's a instructor, probably the way he talks to his students

[@ralfoide]

If you reply "no" to "with me so far? ", then it's a good sign you could learn more on that area. Just pause the video, and learn more on what he's talking about, whether it's Wikipedia, KZbin, or that Brilliant web site... No shortage of videos out there to explain all the necessary physics.

[@ralfoide]

@@MrSvenovitch Videos are interactive. There's this thing called a pause button. Having done hundreds of videos now, I think he knows how that works. I really like his accent, so much easier to understand than 90% of the brits.

[@alieninbellingam]

Just love your dogs!

[@gus2747]

Good video!

[@jessijacobs8]

What a great video and awesome explanations!! 🙌👏🙌 Video also made 100% watchable on repeat thanks to Patxi 🐾💕😅

[@Malkus1]

I really love your videos:)

[@mrkhan2983]

Your dog is so cute . Please discuss propeller little more .

[@jred4421]

Ok, I'm a bit behind the times since this video was produced over three years ago...but...was never aware the Harrier's Rolls Royce engine was counter rotating until watching this video. Was in the propulsion field in the USAF for over 20 years, and not experienced with the Harrier's engine system...I understood propulsion gyro effects, but never gave it a thought about the Harrier. Learn something new everyday. New subscriber here and enjoying the content of mentoring pilots.

[@stephenbritton9297]

"what is a critical engine?" "Any engine attached to MY aircraft!" :)

[@AlexandarHullRichter]

That's right! My engines are all critical engines! I don't care quite so much about your engines.

[@iskandartaib]

Actually there are cases of airplanes with TWO critical engines. The one that comes to mind is the P38 Lightning. It has props that turn in opposite directions, but for some aerodynamic reason - something to do with the horizontal stabilizer and buffeting IIRC - the engines were installed so that at high AOA the thrust for both engines moved outboard of the spinners, which meant that both engines were critical.

[@flavianojose8423]

Nice one

[@olspanner]

Your dog has a gyroscopic effect at times ! Very interesting, thankyou.

[@milesbrown8016]

Well presented…

[@AgentJayZ]

Excellent

[@bena6575]

thank you.. i have a test on turbine engines on monday in class!!

[@jorge6594]

Have an absolutely fantastic day, Mentour! :P

[@AmtrakFan6905]

15:18 cute dog 🐶😍!

[@iamsupersammie]

I couldn't concentrate on what you were saying because of your dog and that's a good thing.

[@johnkelley9877]

This was very interesting! I always wondered if jet engine fans had to turn a certain direction and you answered all of my questions. Thanks for sharing this.

[@son8128]

you should've also explained slipstream when you talked about propeller engines. Great job explaining these concepts!

[@francisromero79]

You're the best!!!!

[@sunnyjacob7350]

Thanks Mike

[@antonoosthuizen1467]

Great video as always. One or two points, though. Engine torque on a propellor driven aircraft is important, the stronger the engine the more the torque effect. Back when we had taildragger planes you had to come on the power fairly gently on take off to prevent ground looping. Tricycle undercarriages on modern planes have helped negate the torque effect on take off but we used to smile at learner pilots taking off with a port wing low attitude because they failed to compensate for torque. The other point is that the P Factor produces a pitch up when increasing power, much like the B737's that you currently fly.However, I guess I'm just nit-picking. I always enjoy your videos and look forward to many more. Take care.

[@VoidIndigo25]

Good video but the best of all is the friendly little dog and his jokes! Liked it !

[@ingmarhendriks8172]

Can you do a vid about flight computers? How do they work. Why are there multiple etc...

[@jonatancordoba7984]

Like the new cam angle!

[@anthonyellsmore4532]

Exelant

[@Inkling777]

With its light airframe and two powerful Merlin engines, the WWII Mosquito had serious problems with these issues, particularly taking off and landing. Search for "mosquito engine failure on takeoff" for specifics.

[@jimrobertson6959]

Yes, WWII was an interesting time of discovery of these engineering problems. The Japanese Zero had massive torque problems that the American pilots could exploit in a dog fight as the torque on the zero was so high it could not bank very well in one direction.

[@duster0066]

Yes yes. The P-38 as well.

[@TheEulerID]

The DeHavilland Hornet, which was roughly speaking a hot-rod, single seat Mosquito with a top speed of 475mph at 21,000 feet had two Merlins, with one geared to run the propeller in the opposite direction to counter this very effect. Another possibility, but not used during WW II was to have two contra-rotating props on the same engine, which is what happened with the Shackleton which had four Griffon engines in that configuration.