Just got home after taking the SIFT and got a 68. Opened TH-cam to relax and this video was still up because I needed a refresher before going in. Couldn't have done it without you, sir. Onward and (hopefully) upward!
Simply fabulous Jacob, love the dedication with which u elucidate hard to understand topics, turned to simple to grasp. Thumbs up brother. Stay blessed and keep posting. 👍🏻🙂👍🏻.
These total drags are also adding "load" to the engine, the power that has to overcome these "loads". What is not mentioned is the friction or mechanical drag the engine has to overcome as well. Frictional losses...
Profile drag is what is also called “wetted area.” It is the surface of the profile. Which the wind will strike perpendicular. It is the area which even if the angle of attack of the airfoil is zero and no lift is produced and all induced drag is gone, that area will still resist the wind however slight. No matter how streamlined the designers are successful, there will always be some wetted area which remains.
Any surface against the wind, no matter how aerodynamic, will have drag. Try moving a butter knife in a bucket of water sideways, you will feel drag, like an oar in the water. Now move the butter knife in a slicing fashion in the water. It "slices" or moves right through the water with much less resistance, or drag, but there still is some drag, however quite small. Change the angle/pitch of the butter knife n you can experiment.. the Rotor
Just downloaded your ebook and while it is a great product overall, you have mislabeled induced drag (c) and parasite drag (a) on the graph. Really appreciate the concise lessons.
Very good Jacob. May I suggest that you light the page from the camera position? This would get rid of the shadow from your writing hand, which often obscures the page.
How are the calculations of parasitic drag made? My gyroplane is an open air constructed of square tubing and I expect the Wright Brothers machine had better drag numbers than mine does.
I’m sure it’s determined by either flight or wind tunnel testing and varied by aircraft. Ultimately the engineers who design the aircraft measure it. I don’t have the best answer for you. I fly and teach, but don’t design helicopters.
Thanks for some amazing videos and some great explanations. However, i agree with Henry Martinez, I believe there is an error in the book regarding parasite and induced drag. Thanks for all your efforts, and all the best!
what are situations where you would want to hang outside of the bucket? are there good weather conditions for example that would motivate you to move right on the x axis if you were in a hurry?
Take a look at my Crucial Speeds every helicopter pilot should know. Flying Max Range airspeed is the most fuel efficient for distance so it’s the equivalent of best miles per gallon. Also, flying at faster airspeeds may be used as an extra bank account when having to fly lower altitudes. Think, if you have an engine failure you can trade off that inertia to charge the rotor for an autorotation. I outline those principles more in my 3 Bank Accounts video.
Induced drag: when the vortices are large/strong/heavy there is a component of force along the direction of vortices that drags the helicopter down or aftwards... _my understanding
You’re still going to have the same types of drag although if you climb there is generally reduced induced flow because the resultant relative wind impacts the rotor different. The reverse is true for descents.
Generally it’s a product of speed. Technically the air gets less dense as you increase altitude so theoretically it wouldn’t increase as quickly at higher altitudes. But this difference would be hard to notice or measure as a pilot.
Generally it’s a product of speed. Technically the air gets less dense as you increase altitude so theoretically it wouldn’t increase as quickly at higher altitudes. But this difference would be hard to notice or measure as a pilot.
I agree. Density decreases at higher altitudes which means the helicopter flies through the air easier, but the airfoils (rotors) aren't as efficient, therefore, equalizing. Or on a miniscule level only meant for engineers/scientists to calculate.
W0w! at zero speed the drag FORCE on the helicopter is according to you large! THAT is not possible You are confusing drag with power , mister. Thrust in unaccelerated flight must equal drag. In hover the Helicopter Rotor Thrust in forward direction is zero, so no drag FORCE, Zero. The rotating blades do have drag , creating a moment about the rotor axis, which the engine must overcome. This moment times the angular velocity is the POWER the engine, after friction losses must provide. In Hover, at zero speed with a tail rotor pushing the tail, The Rotor must oppose this lateral tailforce with an equal and opposite tilted rotor side force. That small force is the only force in the plane of the rotor produced. The rotor POWER is the sum of the blade friction (parasite) power and the induced power required to push the air through the rotor to generate the lift that supports the helicopter weight., So far all the foregoing in hover flight. Some simple equations: Induced POWER of the rotor P = L^1.5 × √(2/π rho) ÷ Dia. Dia rotor diameter rho air density L rotor lift force > weight
Just got home after taking the SIFT and got a 68. Opened TH-cam to relax and this video was still up because I needed a refresher before going in. Couldn't have done it without you, sir. Onward and (hopefully) upward!
New student referred to your channel by my instructor. I immediately understood why. Great 10 minute class worth the time of my life clock. 👍🏻🤙🏻
Fantastic explanations, I’m very impressed with the quality of your videos.
Simply fabulous Jacob, love the dedication with which u elucidate hard to understand topics, turned to simple to grasp. Thumbs up brother. Stay blessed and keep posting. 👍🏻🙂👍🏻.
Thanks again for your efforts and expertise, sir. That explanation makes the charts easier for me to understand.
Great videos! I've been studying the last year for my CPL and your explanations have been a big help!
Thanks Jacob, this is helping me out so much. All these videos are great, I appreciate your effort.
nice video.thanks for sharing
Thank you my professor couldn't teach a bird to fly so this helps alot
Great video!
Excellent!! Thanks Jacob!
These total drags are also adding "load" to the engine, the power that has to overcome these "loads". What is not mentioned is the friction or mechanical drag the engine has to overcome as well. Frictional losses...
Profile drag is what is also called “wetted area.” It is the surface of the profile. Which the wind will strike perpendicular. It is the area which even if the angle of attack of the airfoil is zero and no lift is produced and all induced drag is gone, that area will still resist the wind however slight. No matter how streamlined the designers are successful, there will always be some wetted area which remains.
Any surface against the wind, no matter how aerodynamic, will have drag. Try moving a butter knife in a bucket of water sideways, you will feel drag, like an oar in the water. Now move the butter knife in a slicing fashion in the water. It "slices" or moves right through the water with much less resistance, or drag, but there still is some drag, however quite small. Change the angle/pitch of the butter knife n you can experiment.. the Rotor
Hey Jacob, your videos are so fuc*ing useful for my ATPL(H) studies for EASA exams. Thank you so much!
Just downloaded your ebook and while it is a great product overall, you have mislabeled induced drag (c) and parasite drag (a) on the graph. Really appreciate the concise lessons.
Brilliant. Thank you.
Very good Jacob. May I suggest that you light the page from the camera position? This would get rid of the shadow from your writing hand, which often obscures the page.
Bob Gilchrist. I appreciate the tip. I'm working on improving the lighting setup now. Thanks.
I've been flying helicopters for 30 years but I appreciate your work as it is good to be reminded of the principles!
Thanks Man , good info .
LOVE THE CHANNEL!
Great video 👌
Nice and easy
Good vídeo 👍🏾🚁
Thank you !
Thank you so much it makes a lot of sense now
Jacob what’s the stall in induced drag?
muito bom
How are the calculations of parasitic drag made? My gyroplane is an open air constructed of square tubing and I expect the Wright Brothers machine had better drag numbers than mine does.
I’m sure it’s determined by either flight or wind tunnel testing and varied by aircraft. Ultimately the engineers who design the aircraft measure it. I don’t have the best answer for you. I fly and teach, but don’t design helicopters.
Hey Jacob, the book has A and C labeled differently on the graph. I think it’s confusing me a bit.
Thanks for some amazing videos and some great explanations. However, i agree with Henry Martinez, I believe there is an error in the book regarding parasite and induced drag. Thanks for all your efforts, and all the best!
You really need to get in touch with helicopter online ground school and do videos for them I'm sure they would love to have you on their team.
what are situations where you would want to hang outside of the bucket? are there good weather conditions for example that would motivate you to move right on the x axis if you were in a hurry?
Take a look at my Crucial Speeds every helicopter pilot should know. Flying Max Range airspeed is the most fuel efficient for distance so it’s the equivalent of best miles per gallon. Also, flying at faster airspeeds may be used as an extra bank account when having to fly lower altitudes. Think, if you have an engine failure you can trade off that inertia to charge the rotor for an autorotation. I outline those principles more in my 3 Bank Accounts video.
What is the drag measurement unit? Is there any?
Any one can explain how easy identification of faulty flape limiter?
Induced drag: when the vortices are large/strong/heavy there is a component of force along the direction of vortices that drags the helicopter down or aftwards...
_my understanding
Does the drag force in the climbing direction matter when the helicopter is climbing?
I don’t think I understand your question. Can you restate it?
@@helicopterlessonsin10minut10 What drag forces occur when climbing?
You’re still going to have the same types of drag although if you climb there is generally reduced induced flow because the resultant relative wind impacts the rotor different. The reverse is true for descents.
How are the max range speed or pitch calculated?
I cover it and more in my Crucial Speeds video. But simply put you divide knots/fuel flow at different speeds to find the highest number.
How parasite power varies with increase in altitude ???
Generally it’s a product of speed. Technically the air gets less dense as you increase altitude so theoretically it wouldn’t increase as quickly at higher altitudes. But this difference would be hard to notice or measure as a pilot.
Watching this cause I'm taking my SIFT tomorrow!
hi
How parasite power varies with altitude .
Can anyone throw some light on this.
Regards
Ashish
Generally it’s a product of speed. Technically the air gets less dense as you increase altitude so theoretically it wouldn’t increase as quickly at higher altitudes. But this difference would be hard to notice or measure as a pilot.
I agree. Density decreases at higher altitudes which means the helicopter flies through the air easier, but the airfoils (rotors) aren't as efficient, therefore, equalizing. Or on a miniscule level only meant for engineers/scientists to calculate.
Parasite Drag + Profile Drag + Induced Drag = My Ex
A,bcd,eh
W0w! at zero speed the drag FORCE on the helicopter is according to you large! THAT is not possible
You are confusing drag with power , mister.
Thrust in unaccelerated flight must equal drag. In hover the Helicopter Rotor Thrust in forward direction is zero, so no drag FORCE, Zero.
The rotating blades do have drag , creating a moment about the rotor axis, which the engine must overcome.
This moment times the angular velocity is the POWER the engine, after friction losses must provide. In Hover, at zero speed with a tail rotor pushing the tail, The Rotor must oppose this lateral tailforce with an equal and opposite tilted rotor side force. That small force is the only force in the plane of the rotor produced. The rotor POWER is the sum of the blade friction (parasite) power and the induced power required to push the air through the rotor to generate the lift that supports the helicopter weight., So far all the foregoing in hover flight.
Some simple equations:
Induced POWER of the rotor
P = L^1.5 × √(2/π rho) ÷ Dia.
Dia rotor diameter
rho air density
L rotor lift force > weight
Yes, and the parasite rotor power is D = 3/4 Lift Vtip Cd/Cl
also a simple equation
stop waffling
yeah