Propeller Blade Angle of Attack

Explaining the propeller blade angle of attack to the students at IT Carlow screenr.com/xd4

[@skyshots1685]

13 years on and this has just helped me massively for my POF exam ! Thankyou 😊

[@MrGuily1]

Thank you! So much easier to understand visually than from a textbook

[@tylerjordan1479]

Best explanation on why prop blade angle decreases at the tips. The textbook "to produce a constant AOA" is worthless as an explanation, but this video does so perfectly! Thank you!

[@pejmanjavaheri9758]

Thank you so much for the excellent explanation of the relative airflow on a propeller. I have watched so many videos and I did not get my answer until now. Now, I understand the vectors and the resultant relative airflow for a rotating propeller. I can confidently say that no other video has explained how these vectors are derived.

[@johnroberts7529]

What a beautifully paced and well structured video this is. Many thanks for all your hard work.

[@srisutharsan3089]

Seriously you've done a great job explaining this, keep going

[@b.o8144]

Definitely the best explanation with proper visuals! Thank you Roddy

[@RoddyMcNamee]

Absolutely! The direction of the relative airflow should be pointing towards the propeller and not away from it!

[@tomizzo11]

This is a great video. Very informational and cleared up several misconceptions I had regarding angle of attack vs blade angle. Keep up the great work!

[@gracehu4692]

Thank you so much. I am working on CFI. I was trying to find this perfect explanation for a while. Finally I got it here. Good Job!

[@WordofSpirit]

this is what i was looking for. Now i can understand the other aspects of propeller blade bitting the air, blade and pitch. Thank you very much

[@abdelazizmounji7798]

Cristal clear explanation. Thank you so much for putting this together

[@AeroMarko]

It's just that the rotation in this case as you have shown is anticlockwise or left hand rotation. You have to look at the propeller from inside the cabin. Most of single engine pistons have clockwise rotation, so probably this propeller is also clockwise rotating, which would mean that it is rotating in the other than shown direction. Cheers mate

[@NikitaKaminskyy]

Amazing explanation! Simple, clear and precise

[@anandkelkar89]

just to check, the relative air flow should be pointing opposite (as in pointing towards upper right corner)?

[@st-rochguy4909]

I ve been researching that for a whole week, thanks mate

[@richardthuman3209]

Roddy, thanks so much for this video. This is the first time that I actually understand how the different forces changes the Aoa

[@TaimauChan]

Thanks so much ! This help me to visualise AOA of propeller which is much more clear than those text books !

[@BengalMailbyDeep]

Thanks man...the way u explained made me understand everything in 4 mins..which I wasn't being able to do by going thru the book fr hours

[@stvrstc]

Best explanation I have ever seen, thanks so much....

[@doenja3319]

Wow, ive been looking for a video like this for a while. Finally i understand this. thanks!!!

[@abdullahmaruf7912]

A very very clear presentation

[@joaopedromuller7266]

Dudee, thank you so much.. You have no idea how it got simple after i watch yur video...

[@larryphotography]

This is the best video I found on the subject thank you! What really got me every time was that cross section diagram with the graphs. I had no clue what part of the propeller we're actually looking at. From what I can understand (and it would REALLY help to have an animation of an airplane going into the position of the graph before disappearing and leaving just that cross section) we are looking at the SIDE of the propeller as the plane is flying in from the right (and thus airspeed coming from the left). Is this correct? Thank you!

[@RoddyMcNamee]

Yes, the cross section is of the propeller blade looking in from the side, with the aircraft flying from right to left.

[@stevepegg2269]

yea...but air speed is determined thrust/clime/Descent relative to earth/gravity. So to increase air speed- either pinch change (less gravity) or increase in power

[@Elizabethlc26]

YES. UGH YOURE BETTER THAN MY INSTRUCTOR. THANK U

[@funfacts5821]

wow best explanation i was confused now its all clear thank you so much🙏🙏

[@animexd5083]

How we have to Check the Direction of propeller rotation. Whether it is Clockwise or anti clockwise. From which position we have to check? I mean. by Standing infront of a/c or Sitting in pilot Seat?

[@RoddyMcNamee]

Standing behind the aircraft and looking forward.

[@animexd5083]

@@RoddyMcNamee thank you Sir!

[@Andreas20a]

Sir, thank you very much, from you i understood how the propeller works.

[@RoddyMcNamee]

AviationMy, sorry for the tardy resonse, but I''Ve just seen your comment. For me, Blade Angle and Blade Pitch are the same thing.

[@samoo8933]

I canot understand how the relative airflow is opposite to the propeller motion ? Should the realtive airflow comes from behind the falt side of blades not from the ground as your drawing them ?

[@janicewong9622]

Thank you so much you explained it so well with those clearly-illustrated diagrams

[@chandrashekhar-oq8io]

Superb sir. Hats off to your explanation.. Thank u so much

[@HossainSiddiqui]

at the end, i think there is a typo error with "a decrease increase in AoA". Need to remove 'increase'. You have simplified a hard stuff.

[@RoddyMcNamee]

Thanks for the feedback

[@bikashburnwal2029]

Elaborate what would be the effect when both acts at the same time sir...this video was really helpful, still there are some doubts

[@anders6591]

Great Video, thank you so much!

[@iruxcheri]

At 1:44 , the direction of relative airflow vector is incorrect. It should be opposite to what you have drawn. Great explanation though.

[@RoddyMcNamee]

Yes, it is drawn incorrectly. I only noticed it after I’d posted and fully intended to remake the video. It’s now years later and I still ave great intentions of remaking it. 😀

[@iruxcheri]

@@RoddyMcNamee Naah , it’s a great video. Why spend time on it when you can make one on a different topic for us :)

[@ericnelson4651]

So the final question to tie this all together.. can a Fixed pitch propeller, operating normally (no malfunctions), engine operating normally to spin the prop, etc…..Can it stall?

[@RoddyMcNamee]

In flight, I would say the answer is no, it is very unlikely to stall.

[@airmett8939]

I don't understand why the propeller is always drawn pointing so far forward of the plane of rotation (such as at 1:46). Aren't the propeller blades flat with the plane of rotation?

[@jonnyball9375]

Great, well explained. Good for PPL learning.

[@jonammp]

Superb explanation.

[@aviationMY]

Hi I want to ask, in aircraft if blade angle increase what happened to the propeller blade pitch? (increase or decrease)

[@DetEJagDe]

Cheers man! I didn't understand it at PPL theory, but thanks to you I do!

[@fjficm]

I'm not sure that this is correct. But I look at this from a wind turbine perspective but the principles are the same. Angle of attack (i) =Angle of incidence b/w relative wind and direction of motion of the plane (I) - Pitch angle (alpha). Given that the pitch angle remains the same an increase in I will increase the AoA. This is done via increasing wind speed or increasing plane velocity. Is this correct. Im unsure about propeller planes but can the pitch of the blades vary accordingly to optimise the AoA(i) so as to optimise Fd/Fl

[@waynepetrevan]

For me the cross section of the blade looks wrong for a clockwise rotating prop and the airflow direction vectors you show. Maybe its just me......

[@rustammaniiazov1208]

very good explanation.

[@clipoff]

Angle of Attack ??? what does it effect

[@kevinoulahan9779]

Why don't we have compact telescopic 3 tears propeller blades today for use in PAV's ( personal air vehicles) so that they can be extended in flight and retracted for driving on the ground ? For a real life all terrain vehicle?

[@RoddyMcNamee]

You're welcome. Glad it was of some use.

[@jeremyloyam7094]

very well illustrated thanks man..

[@elroydsouza7196]

Amazing video Thanks. I had a doubt though , So the angle of attack at tip of the propeller would change because it moves at a higher angular velocity that the root of the , Blade correct? If not can someone clear this doubt for me ?

[@RoddyMcNamee]

No, the blade angle at the tip is smaller because the rotational velocity (V) is greater at the tip. The angular velocity ( omega) is the same all along the blade. The equation is: V = omega.radius At the tip the radius is at the maximum so the velocity is at the maximum.

[@patteo8886]

Thanks. It is very clear. Way to go!

[@737silver]

Thanks a lot. Bristol Atpl books are far away of fully understable explanation in principles of flight and other subjects :((

[@prathameshvichare8517]

That relative wond component is wrong, please correct it. By the way the video is informative, Thankyou.

[@tintinfan007]

Sir, can u tell me how this value of "vector due to rotational speed" is obtained ? is this actually the centrifugal force acting on the blades?

[@RoddyMcNamee]

No, it is the velocity vector due to the rotational speed. V= omega.r. where omega is the rotational speed in radians per second.

[@tintinfan007]

@@RoddyMcNamee oh u mean angular velocity ?

[@yoonjaekim8523]

Thank you I couldn't learn this in my college

[@戴鹏-o7y]

Very clear explanation indeed

[@pancake-de5iv]

thanks, i was going to claw my eyes out playing flyout

[@yasiruilesinghe2611]

what happens if the air speed is constant

[@pravinchavan643]

Perfectly explanation!!!! Cheers

[@lsx001]

Thank you so much you explained it so well!

[@CapitanoGUC-gf6el]

And what is the ideal angle of attack ?

[@RoddyMcNamee]

It depends on the prop, but usually the best lift / drag ratio of an airfoil occurs at about 4 degrees.

[@07015678]

Thanks Roddy. I presume this is for a fixed propeller?

[@RoddyMcNamee]

Yes, this was for a fixed pitch propeller but the principle can still be applied to a variable pitch prop.

[@gabrielsleiman69]

If you increase the RPM therefore increasing the speed, how would it affect the AOA?

[@RoddyMcNamee]

How are you increasing RPM? Are you increasing the power to the engine, then there will be an increase in power delivered by the propeller, or are you increasing RPM by selecting a more fine blade angle?

[@KingRichard920]

*Assuming a fix pitched propeller for simplicity.* An increase in RPM does not necessarily assume an increase in airspeed. For example, slow flight relies upon pitch for airspeed and power for altitude.

[@June-lf5hx]

@@RoddyMcNamee Hi, i have the same question. why increase the RPM but the airspeed is the same? I didn't understand from your reply. Could you please explain more??

[@brokozor]

If the airspeed increases, this will cause a DECREASE INCREASE in angle of attack? Please DECREASE or INCREASE?

[@RoddyMcNamee]

All other things being equal (Blade angle, RPM), as airspeed increases, angle of attack will DECREASE.

[@brokozor]

Thank you Roddy, I was refering to last few seconds of the video, there is both decrease increase. Yup, speed up = angle of attack going down:) thanks for the video! Well made!

[@040_shivangpatni_aero3]

Well explained, thank you

[@ambition221]

I did not understand the vertical speed. From where it comes from? 😔

[@codyprice0295]

Vertical speed is a result of higher propeller RPM that line is the measurement in force hitting the bottom of the airfoil. The lengths of the lines are 2d representation of the amount pressure exerting on the airfoil as the propeller moves faster or slower in that clockwise direction (vertical) or forward in airspeed (horizontal)

[@RoddyMcNamee]

Have a look at another screencast I made about blade asymmetric loading. If that doesn't help, come back to me.

[@eemtech1606]

If the airspeed increases, AoA decreases. How can we increase the airspeed?

[@RoddyMcNamee]

Put the aircraft into a dive.

[@eemtech1606]

@@RoddyMcNamee I see, make sense.

[@comctrevor864]

Is there a video of solving the aoa?

[@RoddyMcNamee]

There are some videos called Propeller Analysis 1, 2 and 3. If they’re not helpful I’ll do one for you next week.

[@comctrevor864]

@@RoddyMcNamee you're the best!

[@RoddyMcNamee]

@@comctrevor864 have a look at this: kzbin.info/www/bejne/eZK5eoGqn7J8p9E is this what you were looking for?

[@samnz502]

A Short clip and so useful , Thank u very much :)

[@mossmh3866]

Great explanation thank you

[@nicholasgenest352]

Yes perfect explanation!!!

[@anishkumarsingh1019]

Very well explained.

[@am-pb4ci]

Great video

[@kedmax1055]

great video

[@AlexanderMcAllister]

Made perfect sense. Thank you.

[@karthikp2650]

First you mention Greenarrow upside inclined. it satisfies vector addition triangle.second time you mentioned Green arrow downside inclined it didn't satifies vector addition. it confuse me. please explain .Thank you.

[@RoddyMcNamee]

The green vector (relative airflow) is pointing in the wrong direction. It should point upwards.

[@williamcrisp7882]

Roddy Mc Namee Thank you. I was confused about this part. Otherwise very good explanation!

[@invershin]

Thank you so much!!! Finally I got it!!!

[@MrAlwaysBlue]

"Tree bladed propeller". I assume its a wooden one then?

[@ejanocrowsnatcher6785]

When he says tree blade propeller and you think wow what a funny accent and then you remember that no wait tree is actually how you say it

[@DaudpotaArt]

Awesome! Just what I was lloking for! Thanks sir! :-)

[@PilotBossify]

This one is great

[@hsfhaz]

So my textbook explain it right too but instead of talking about movement of airflow it use RPM and foward speed of the aircraft... Which is the incorrect way to explain the relative airflow.

[@RoddyMcNamee]

The relative airflow is the vector sum of forward speed and prop airflow due to RPM. So there is no difference in how they are being explained.

[@maierj-m2621]

great job!

[@Kyoze0]

thanks m8. thats very helpful

[@samythebull]

easy to understand Thank you

[@RoddyMcNamee]

Well I suppose on the bright side it wasn't BORRRRRING.

[@saif8912]

Omg thank you!! You literally saved my ass!!!

[@omkarghase4653]

nice one propeller blade ................i understand

[@djvinrapacitiez]

very useful..thank you very much...more videos on gas turbine please:)

[@Jmaster009]

BRILLIANT

[@ssunthra]

Thank You...nice and simple...

[@RoddyMcNamee]

You're welcome.

[@vikingpary]

Thank you

[@yanngumbs97133]

GOD DAWM thanks finaly i understand !

[@ramanpal1763]

straight fire

[@captainduffman1]

great job ,thanks

[@tintinfan007]

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