What Factors affect Vmc?| Minimum Control Speed (Part 2)
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- čas přidán 1. 08. 2024
- This is Part 2 on Minimum Control Speed. Vmc is the speed at which the rudder looses the ability to offset the asymmetrical thrust produced by one engine being inoperative in a multi engine aircraft. This speed has a variety of factors affecting it. This video looks at those factors and discusses how they either increase or decrease the speed which rudder authority fails.
This video is not intended to be used for flight training purposes but rather to act as a informational guide. Consult a properly certified and authorized flight instructor for training and follow all FAA regulations pertaining to aircraft operation and training.
Chapters:
00:00 What Factors Affect Vmc?
2:17 How Vmc is Certified?
3:21 How does Thrust Affect Vmc?
4:45 How does Rudder Authority Affect Vmc?
7:14 Queen Air Accident Explanation
9:42 How does Drag Affect Vmc?
11:40 How does Weight Affect Vmc?
#MultiEngineTraining #FlightTraining #LearningToFly
This was probably one of the best vmc explanations on CZcams. Thanks so much. Huge help
Years ago, BE65, Queenaire ... engine failure on climbout, heavily loaded, four pax, fortunately was still in pattern, coincidentally on a downwind. Feathered nr. 2, briefly continued climb, then turned into good engine, gear down, easy landing. BUT .... did my damndest to continue a descent, and, by chance having just completed a detailed flight school program on the Queenair, knew to keep the airplane well above Vmc .... landing was good, and otherwise normal.
Great job explaining those factors. I'm currently studying before starting training for my multi rating. Thanks for the video.
Years ago, BE65, Queenaire ... engine failure on climbout, heavily loaded, four pax, fortunately was still in pattern, coincidentally on a downwind. Feathered nr. 2, briefly continued climb, then turned into good engine, gear down, easy landing. BUT .... did my damndest to continue a descent,
Great presentation!
i keep on watching your videos man ! You have done very nice work. Thank you . this is good stuff. Simple, and to the point. The way you explain things / concepts is very nice and effective.
Thank you for the kind words…
Great video!!
Amazing videos. Thank you
Glad you like them!
8:52 the problem with this statement about the rudder is that if he banked towards the bad engine (the left) then his rudder input should be right rudder. If he is putting right rudder, in a left bank the lift component would have been facing down, not up. So I am not sure I understand your reasoning for the vmc increase.
However I do remember being taught that every degree into the bad engine increases vmc by a certain amount, just not the reason.
Go watch the first video in this topic. It discusses the reason banking into the operative engine decreases Vmc. Wing Lift begins to bolster or increase the horizontal forces helping to prevent the Vmc Roll which is why when you bank intro the inoperative engine you raise Vmc. Banking towards the bad engine and trying to maintain altitude was decreasing rudder effectiveness.
That's Queen air VMC roll not because they simply turned into dead engine but they probably did so at "Low Air Speeds" way below even blue line.
If the plane is flying at 150knots that shouldn't be an issue but you're right, why tempt fate. Easy to make turns into good engine or at worst, fly straight to a off runway landing area without the need to turn at all. Simply land the plane safely.
Ive heard that if you low in altitude you could he very close to your okanes stall speed.
If your up at 10,000ft you vmc soeeds typically would be 10 knots higher. If if your vmc speed is 57knots at 10,000ft vmc speed will be 67knots genreral rule.
So it might be better to practice any vmc demo to get multi engine rating at a higher altitude?
Actually, I think you’ve got it backwards… The dynamic pressure (a.k.a. indicated airspeed) would always be the same except the engines lose power if they’re normally aspirated at altitude. So basically the higher you go the lower Vmc gets because your engine power is less with higher altitude. You get lower speeds at higher altitudes; plus a higher margin of safety so I always did them 5,000 AGL or higher.
A hight Vmc is good or bad ?
A high Vmc means if you loose an engine in a critical phase like landing or takeoff, you’ll be much closer to the speed that you’ll loose control of the aircraft than if you had a lower Vmc. Sometimes this is completely unavoidable but the purpose of the videos in the multi engine training series is to help us understand what affects and causes VMC to increase.
Can you share the powerpoint ? PLease
I don't think there is a way to do that on this platform but I'll see what I can do!
Why is there smoke coming from the doorway behind you?
It’s my humidifier! 😂
Welp I would have never noticed that lmao
So let's say hypothetically, That your left engine was out, you banked 5 degrees into the right engine
You needed to make a left turn to line up on final.
Could you just make a 10 degree bank to get a 15 degree turn since you're putting 5 degrees towards the right as your correction for the turning tendencies?
I'm sort of implying that if you use 5 degrees to hold relatively straight course, it would make sense that it becomes the new 0...
Sorry if its a loaded question.
Great question! My statement about banking into the operable engine during turns was intended to be in the context of climbing (performance) turns. During the landing portion of engine out emergencies the operable engine will most likely not be at full power. Because of this Vmc will be much lower and the amount of bank into the operable engine will be less because of less asymmetrical force.
In all practicality you would do whatever control inputs were necessary to maintain the best single engine climb speed as a minimum air speed and flight control positions to stay on centerline during landing. I don’t think (nor in practice used) my bank into the operative engine as my new 0 degree point but rather adjusted it as needed depending on the scenario… does that make sense?
The 5 degrees bank applies only in a constant heading situation.
What is really important is the sideslip angle, which is not measured by anything in the airplane unless you have a yarn in the middle of the windshield like gliders tend to have.
Sideslip towards the good engine (to the right in your example) helps with control because it pushes the fin to the side you need, to the same side that your trying to push it with the application of rudder (that is to the left, meaning nose being pushed to the right, to compensate the good right engine trying to push the nose to the left).
But sideslip comes with a price: Extra drag so less climb performance,
Ideally you want to keep zero sideslip, and that requires about 5 degrees of bank into the good engine at Vmc and 2 to 3 degrees of bank at Vyse (blue line: best climb speed with a single engine).
As long as you keep that zero sideslip condition, it is the same to turn left or right.
The question is, again, how do you know? So because you don't it's better to turn to the right, and risk a bit of right sideslip that will impact performance, rather than turning left and risk a bit of left sideslip impacting controllability. Or watch the clip of the Queen Air in this video.
That's basically correct. You don't need as much bank angle turning into the dead engine to get the same rate of turn as you would turning into the good engine. Whether going straight or turning into or away from the good engine, always have a half ball into the good engine.
At my school I’ve been taught “raise the dead” to remember which bank to use for an inoperative engine.
Raise the dead ENGINE.
Sounds like a “killer” idea!
@@The_Flying_Mechanic hold up are you saying that’s bad advice? Or was it just a pun on dead
@thenelsonbruhs722 just a pun! I didn’t realize it might sound like I was saying it was a good way to die! I reference “raising the dead” in this video and the second part of this lesson!
The main reason for doing this is to put the aircraft in “zero side slip” so you can minimize drag and maximize the performance on a single engine!
@@The_Flying_Mechanic that’s what I figured