YOUR FLIGHT INSTRUCTOR WAS WRONG! - Simulated vs Real Engine Failure 

I would like to point out the propeller is merely a big fan that keeps the pilot cooled. I know this because when it stops the pilot started sweating.

9:45 Minimum Sink speed (Vms) is not the same as Best Glide Speed (Vg). Vms will give you more time in the air but you will achieve the highest glide ratio and cover more distance at Vg.

This is a great question for Destin at Smarter Every Day.

This makes absolute sense. The angle of attack on a moving prop is going to be more in line with the chord then on a stopped prop.

Idle the airplane on the ground, take a “thrust test” with a windometer. Whatever speed your propeller pushes air at idle speed will show you at what speed your specific prop generates drag instead of thrust.

As usual, great content with a clear and concise direction. My friend was telling me that he was looking into buying a Kitfox yesterday, I told him to check out your videos. He told me he’s already watched them all! Lol, I hope Kitfox is thinking about a partial sponsorship for you, as I am also looking harder at the light sport aircraft thanks to your videos. Talk about putting the fun back in aviation. Great job!

I must say it’s very refreshing to see you guys as friends and so passionately enjoying what you do. I made it to solo in my lessons many years ago, can’t fly now but I so enjoy watching your adventures!

This type of real world testing with light aircraft is so important. You guys are getting it right. My hat is off to you.

Try pushing a corkSCREW staight into a cork without spinning it........what part of a screw don't people understand?

I had an engine out in a PA-20 at 1,000'agl. That thing came down like a streamlined crowbar! Glide is definitely a little better with an engine at idle

Great piece! Was forced into my first simulated engine out on return to base by my cfi the other day in 7eca citab! Was a great experience, loved the pressure, everyone should perfect it and practice it often Keep up the great episodes! Cheers!

What a GREAT real world application and test. Great for ALL pilots not just new ones. As you see here, everyone was learning. Thanks guys love your videos!

As an aviation and history fan i have an interesting fact for y'all. The germans knew this in ww2. And they wanted to be able to glide as far back to their territory as possible if their engine was shot or died. To insure best glide they installed spring loaded pins right behind the prop of their planes that the pilot could pop out to stop the prop from windmilling and causing drag. (Doubt it was nessicary a v10 or v12 is probably pretty hard to turn over) but none the less they definitely paid attention to tiny details. Have a good day everyone, fly safe.

Wonderful lesson.

Great video. I subscribed as soon as I saw your intro. I could tell it was a well managed channel and something that I'd enjoy even before the commentary began. Thanks, I'm looking forward to exploring more of your videos!

Great video, thanks Trent. My instructor back in 1996 in the UK told me that in reality with a stopped engine expect to descend faster even at best glide and to be a little faster during the flare to compensate for less airflow over the elevator. I’m also a glider pilot so I am always checking for landing spots as part of my cruise checks. You have a great channel.

That was a great video!!! Good reminder of a lot of things that you hardly ever think about as a corporate pilot in daily flight ops. It’d be really cool if you guys could come up with more ideas you could myth bust. 👍

I've done many engine idling and engine off comparisons in my Rans. Idling it will go on and on and on, but when I shut off the engine it would slow down tremendously. I will say this that when the prop stopped windmilling it was noticeably that the airspeed picked up slightly. The difference is when the engine is actually not running. Windmilling is drag. No notes on this just hundreds of dead stick practice landing all the way to the airport.

"Props" to everyone in this video and @Trent Palmer for fearlessly discussing this topic, for the sake of proving it, confirming it, discussing it, and not being afraid of being wrong. This is about "really knowing" which is invaluable for so many people flying so many different STOL planes. Outstanding.

Loved the theory Trent. Would love to see more tests/theories tested in the future. Especially considering you have a bunch of experienced pilots around you with slightly different airframe/motor combos. Great video as always. Looking forward to the next one man!

Hey guys I just have to chime in on this one as a guy who survived an unplanned engine out. I was a 75ish hour pilot. I had rented a Cessna 150 just like the one I had done most of my training in to build some long xcountry time. Long story short. The engine died at pattern altitude as I was over flying midfield for a left downwind. In my head I was startled that it stopped then oh well no biggy, I have practiced this how many times with the Instructor. I very quickly realized the difference between an idling propeller and a windmilling propeller. I thought for sure I was going to park it in the roof of some shed just outside the airport fence. I landed on the runway about 30 degrees off runway heading. I'm sure angels helped me do what I did. The only damage after all said and done, outside of the engine itself, was the tail tie down ring. I was really shocked how much shorter my glide was. I now try to warn other new pilots about that. A couple days after the incident I got to talk with one of the test pilots from Cessna. He said the decision to "stop" the prop or to let it windmill has to do with altitude above the "runway". You have to be high enough for the benefit to out way the altitude loss You WILL experience in trying to stop the prop. Anyway that was my experience.

Dang, I'm early. Great video Trent, as a flight student currently working on my commercial license this video will definitely bring up some great conversations with my CFII.

Great video Trent! Thanks for sharing!

Great job on getting everyone to think about this. We have all trained with engine out scenarios. The real life engine failure is the real deal and no turning back. One must always be prepared, even if it is just running the scenario through your mind, as most of us are doing now. Great job on getting us to think!

That's not even a question for anyone who has had an actual engine failure. It is very noticeably more drag stopped...

Fantastic video, one last point for you to consider in the spirit of your initial debate, when the prop stops for real and WILL NOT restart - does time subsequently pass faster or slower?

This phenomenon can be explained relatively simply. In general, for a fixed-pitch propeller if the airspeed of the aircraft is GREATER than the pitch speed of the propeller (propeller pitch multiplied by rpm) then drag will be created by the prop.

Trent, I think this is one of the best videos you have done yet. I love when people prove/disprove controversial topics with real world examples. The prop pitch can be used to determine that point at which the prop is either driving or being driven (creating drag). For example, my prop is a 43 pitch. Idle on the ground is about 600 but that's partially loaded so let's estimate unloaded idle rpm at 1000. 43" per revolution gives an unloaded (zero AOA) speed of 40.7 MPH. Slower than that and the engine is pulling air, faster than that and the air is pushing the engine. Now look at a L/D curve and remember that the prop is an airfoil. When it is being driven by the air, it is at a negative AOA and at some point, that airfoil will hit the critical angle and stall. It is still producing "lift" aka drag when stalled, but less than when windmilling. If the engine is switched off, the windmilling prop is using energy to pump air. If the engine is just idling, there is at least some energy added to the equation from burning gasoline, even if the engine is being driven by the air. Good job on the video. I know these can be harder to make than just a simple vlog but I find them much more engaging.

It would be interesting to do an interview with an engineer at Hartzel or NASA regarding this question

notification squad here... Good talks... and having you guys not just talking but to testing different scenarios.

Trent and friends... you guys are my hero’s. You guys rock!!!

hey Trent! thank you so much for all the adventure videos you do, you really capture some of the most beautiful landscapes ive ever seen on screen :) you only see beautiful stuff like this by going off road or by air! you got yourself another subscriber!

Some thrust is better than no thrust.

In my 53 years of being a licensed pilot I always suspected that, but never once questioned what I was taught. Very interesting.

Fantastic video! I love the technical stuff. I've been wanting to go test my plane to see the difference between what is published best glide and what it actually is with the bigger tires, bigger motor, and VG's. Inspired me to go out and finally figure it out!

EXCELLENT. Thank you for talking about this, and putting it to the TEST! I really love you all and I really respect what you do. I've been following you, Trent, for some time now, not too long after I started following Mike and Draco. I am a student pilot at the moment. I will be sharing this video with my ground school and both of my instructors. This is excellent knowledge, and a great test. I'm not sure they'll allow us to try this test in the school's 172s, but it is very valuable even to simply consider and be ready to expect different dynamics with an actual engine out and a non-rotating propeller.

You must calculate the pitch speed 1st. Take the pitch of the prop times the RPM to get the pitch speed, which is a theoretical distance the prop would "screw" into the air, per revolution. If the aircraft is going faster than the pitch speed, then there will be a drag induced, slowing your airspeed. If the prop pitch speed is more that the actual aircraft speed, then there will be a thrust component added, increasing airspeed. A windmilling prop creates the most drag. The difference in drag between an idling engine, and a stopped prop is much closer to each other, and more difficult to predict. I would think that an idling prop would be just like a car coasting down a hill in 1st gear, producing a lot of drag, but it looks like you guys are proving me wrong. Interesting thoughts to ponder.

I was expecting you to hesitate when you restarted the prop because you thought about yelling clear prop at 6,000ft.

This is an awesome video Trent! I would agree with you that idle would help a bit more but I'm sure it depends on the plane. I come from mainly a glider background and one soaring pilot in particular, Dick Johnson did over 100 sailplane evaluations. One thing he mentioned is that it is crucial to preform more than one test of each category since you can hit sink and lift at different times. He also would do his tests early in the morning to try to minimize any thermal disturbances. Awesome videos you're posting man, keep it up!

Thank you for risking your planes to do this experiment! I've practice many practice emergency landings before, but always with an idle engine, my CFI said they would never actual turn off the engine, because if we cannot turn on the engine again for some reason that would be a real embarrassing day for us.

Another question would be if you pitched up to stop the prop, would you lose more due to regaining airspeed versus letting the prop just windmill? I know in my Cessna 150 you have to slow it down quite a bit to stop the prop.

ok, I had to watch this one again. what if you had a anemometer/wind speed indicator you could put out the window and read the wind speed, with an idle, and with engine stopped. if you don't have one, let me know. I could sent you mine. mike

I absolutely love this! You guys really are making people want to question their flying abilities and then go out and test them and learn more. My next flight with an instructor will include a full stop landing with engine out.

Good video. There are so many aspects of flying, it's nice to see that you can take a discussion and turn it into a real demonstration. I agree that an idling engine is producing thrust, versus a dead engine, with or without a turning prop.

The worst: A feathered prop windmilling backwards. Fun times.

I only subscribe to channels that are willing to present both sides of the argument and then encourage their viewers to go see the results for themselves. You just earned my second subscription, Trent :-p lol

This is hands down the best channel on youtube right now. Please! Don't stop filming content. You can easily be the best "RU-vidr" if you keep this up.

One of my favorite vids. More like this please.

This is one of the great pilot debates of all time, even in jets. Military pilots too often deal with flame-outs, and an air start is usually about the best you can hope for, prop or jet. My personal experience tells me the windmilling prop is the least desirable situation, while the prop producing partial thrust is best. It's such a dynamic situation with so many variables that I'm not sure there is a one size fits all answer. Testing like you did is highly desirable, and kudos to you guys for doing that.

I think the root of this is people confusing the windmilling prop with an idling prop. Then the fish story continues to grow.

What a grop of professionals! !! !!! It sure gives you a tremendous amount of confidence flying with such intelligent pilots. GREAT video.

I want to say - as a PPL - thank you for this video - there is zero doubt in my mind that this collaborative, thought provocative, narrative of a few pilots that wanted to challenge the questions that we all face and ask ourselves, especially when flying family - whats my glide slope - how far can I go - when do we commit to off airport alternatives - bottom line - this simple youtube video will save lives -- period.

That’s why I fly gliders. No propeller no prob :)

Have Mike Patey try it with Draco with the prop in beta.

Great video, and a great topic! The comment that (I think) Mark made early on about idle thrust being relative to airspeed (and thus apparent wind) seems spot on and may be a factor for faster planes.

This was awesome thanks Trent!!! Just remember to kill the mixture, fuel selector and electronics before touchdown in a real life scenario to minimize fire potential!

That 13 seconds is around 1300 feet travailed forward per 1000 feet of altitude.

Great discussion! I stopped the vid, because I want to see how this plays out - A CFI will pull the throttle and tell you "Engine out" But as Mike/Mark???? LoL says, is the glide profile accurate vs a stationary prop?. I think the most definitive way would be to test this in a NASA (Or make one yourself) water flow dye tank, where you have streams of UV dye injected into the water. That would remove all variables, from relative wind,, gusts, etc, thus creating a perfect test platform. In a fluid dynamics test, which this is, the more variables that can be removed the better. When I was in college, I drove prof's nuts because I wanted proof if at all possible. Math is pure, theoretical physics is more or less pure,, (practical) physics is messy . -- OK! Back to the video - thanks guys!

man this is a great discussion,, we need more of these please

Great discussion and test guys! Keep up the great work!

Anyone that says that an engine at idle doesn't produce thrust has never had to disconnect a GPU from a 400 series Cessna. My hat was 50 yards away in the ditch off the end of the ramp.

You need a wind tunnel.

Thanks guys. Great practical demo! More like this please ..

Excellent exercise. Thanks for this.

From my experience with RC planes stopped props tend to cause less drag. Whenever you want to land short on planes without flaps, run the prop as slow as possible. Just my RC experience.

Man Mike look like Bruce Willis lol

Great video Trent! I really appreciate this type of content. Keep it up!

Love the “techy nerdy” discussions Trent!

Go and jump in a motor glider and set yourself up at best L/D and idle then turn the engine off and see what happens... you will pitch down to maintain the same speed and best L/D then go and feather the prop and watch the nose come up to keep the same L/D. You will always be flying for best L/D in an emergency situation. Just ask any motor glider pilot. Why don't you make a polar curve for prop idle and prop stopped? That will solve it.

Great video but your title is horrible. As a full time flight instructor for over 15 years, I cringe when I see titles like this and honestly am irritated by them. But I am also well aware that there are a lot of flight instructors out there that do not train on the fundamentals of topics like this one. A student should never be taught to judge glide based only on numbers, but should be taught most importantly to be looking outside at what the actual conditions are and what the glide is doing based on outside references, and how to adjust accordingly to whatever the conditions are. If you watch outside at what your glide is doing and make your judgements based on those outside references, it really shouldn't matter whether the engine is at idle, windmilling or completely stopped, or what your descent rate is. Unfortunately there is a huge lack of training on subjects like this, which I know is where your title comes from!!! Most flight schools and insurance companies will not allow training to be done by shutting the engine (single engine airplane) off, so we train the best we can. But a good instructor will teach students that there is a difference in glide and descent rates based on things like prop condition (as in this video), relative wind direction, advection conditions and available landing locations. Thank you for doing this video, I will use it with my students to show them what those conditions look like since we are not able to do it in most of our training airplanes. Great video, just wish you would have chosen a different title.

Excellent video ... Thank you guys for doing this!!

not just entertaining but informative, another great vid !

This does does not apply to me as my Learjet lacks a prop.

Idle and wind milling are not the same thing.

Great stuff guys! Thanks! Learned a lot, can't wait to try it out!

All of these guys are such good communicators!

With model airplanes, it's completely different. An actual deadstick is completely different from simulated deadstick. An idling prop on a model plane does act like a massive airbrake. I've seen many pilots who practiced simulated deadsticks no problem, end up way overshooting the runway during an actual deadstick because it glides to much farther / faster. Sometimes to the point they crash into the fence at the end. With electric motors, and their adjustable braking, you absolutely don't want the prop to stop turning when adjusting. For aerobatics it's common to setup the prop brake to slow your downlines. But if the prop brake is too strong, the prop actually stops, and your downlines get way way faster. Massive difference. But this is purely with models. Much lighter relative to scale ratio, much bigger prop relative, and much higher power to weight ratio.

Content with knowledge is the best! Thanks!

Excellent!! Great demo

Excellent demo

This was great! Exactly the type of things I want to know as a non-pilot who may, at some point in the future, get his pilot's license, or an ultra lite aircraft. Nice work, Trent & crew! 👍👍

Very much enjoyed getting to watch the deliberation, and then the actual tests. Very good conclusion given the plane types and conditions.

As always Trent great job!!!

Awesome awesome video. This/Your content is cutting edge. You should consider making a longer doc style video about bush flying or something around aviation. These videos have rekindled my love of flight. You’re doing a great thing.

Cool video! I enjoy the techy, nerdy pilot talk.

Hesitation is the end preparation is your friend. Great video. This was a good conversation follow up and test. Most people have know idea until it happens to them.

Trent Palmer does science...excellent discussion👍

Great video topic and demo.

Nice discussion and tests, done in such a light hearted way it made me snicker.

VERY good points, Trent.

Nice blog thanks Trent 😀

When I practice my glide approaches I've been instructed to increase my aim point down the runway for that reason of safety and making sure that you are going to make it. Nice video!

Love the way you guys operate. I've worked for some 'interesting' aviators.. but you all are a class act. Hats off. :)

Was awesome Trent, answering and proving the total engine out theory versus idle engine could save someone’s life someday!! I learned something from you Cow Boys today!!! Thanks a ton!!! Now I know!!!!!!!!! P. s. Nice seeing you guys all working it out together!! Mike and Cory are awesome to have as flying partners!!! Fly low, fly safe !!! G- Man

Thanks for the excellent discussion. I really enjoy the more techy videos.

Thanks great test and food for thought.

Pretty cool video. Thanks guys.

Really good question and it's a question that instructors need to touch upon with their students. The students need to be aware that actual engine out situations will result in a shorter glide ratio than the simulated engine out situations that they practice. Excellent video!

I love this video! Would love to see more technical theories put to the test!

Thanks for the test !!!!!!!. Really thought out and executed !!