Propellers Explained

I'm by no means an expert but I feel I have at least a pretty good handle on how propellers work. I'm sure I got some stuff wrong so feel free to correct me in the comments.

[@symcardnel1741]

Gotta give a guy props when deserved! Great info thanks!!!

[@mmatt]

Hahahaha! Nice....

[@ezntertainment3601]

Badam chhh

[@thepurpleufo]

You said that you're not an engineer or an expert...but...you just described the workings of a propeller better than any engineer or expert I've ever heard. Great job.

[@mmatt]

Thanks! I'm glad my ramblings made some sense after all. :-)

[@russellsmith3825]

For those that remember Paul Harvey, he would have described it as shirt sleeve English, engineers have trouble speaking it.

[@jackhart8435]

I think you explained propellers really well, enough technical info with language the common pilot can understand 👍

[@flierbill]

You sound very knowledgeable, that's expert to me ! good video , thanks for sharing

[@EatPezzzz]

The reason 3 blade props run smoother on pushers is because there is a high pressure and low pressure zone below and above the wing. As a 2 blade prop spins, each blade alternates between the high and low pressure zone at the same time. The blades of a 3 blade prop doesn't come in/out of these zones at the same time.

[@fly-bc]

Good one! Tell Mitch that in our humble experience the best money spent to fix an IVO is to order a Warpdrive 😉😁

[@daviddixon9598]

I love Ivo props! I'm a trike pilot and I have owned many. For ease of pitch adjustment, it cant be beat.

[@mmatt]

You're right, they're great for that. :-)

[@gillesf6692]

Awesome video of how propellers work, I have a Warp Drive on my Trike and it seems quite bullet proof, and again great video,

[@flyingadventuresab]

I thought I knew a lot about this subject, but I learned so much! This is the best I've ever heard it explained. You have an amazing gift for teaching. Well done.

[@mmatt]

Thank you so much for the kind words! Glad it was helpful! :-)

[@angelreading5098]

The twist is called 'Helical pitch' to understand how a propeller blade is made look at one of those hefty ships propellers,as an 'Airscrew' it screws its way through the water,just after WW2 they got to the stage whereby the engine to propeller combination was at its peak in power as a propeller can only absorb so much before it becomes rebundant,so the answer was to develop the contra rotating propeller which is two props geard together for real performance.Its all about a trade off in take off performance with a fixed pitch propeller set at its optimum setting then finding the best cruise performance possible,to that end the designers made the automatic propeller whereby the airscrew finds its own best setting whatever the cruise or take off situation.Great subject matter Matt,please do a similar one on airfoils running through the range from Newtons theory and the Burnelli principle of lifting fuselages,love your wooden hangar and all the interesting airplanes inside it there is another video for you covering the contents of your hangar.

[@RUHDD4HVN]

You put a proper spin on this video!! You must be the spin Dr? lololol!!!

[@mmatt]

*groan* I love it. lol

[@RUHDD4HVN]

@@mmatt Heehee!!

[@lucywucyyy]

id love to have an ultralight with a variable pitch prop, performance would be crazy

[@av8tor261]

Well done Matt. Just wanted to add that propellers act very differently in a static run as compared to in flight. Blue sky everyone.

[@Ivoprop_1]

MMATT THAT WAS AWESOME EXPLANATION OF THE PROPELLERS!

[@ronniemackinnon3237]

Well done matt, And I can neither add nor rebut ur facts and theories . We need some clear skies!!

[@rogerolander458]

Another topic you might have covered is the issue of engine/prop matching. I ran into a situation where the prop manufacture said their prop was perfect for my 36 HP engine and even suggested an initial AOA setting. The engine was new and it's break-in procedure called for running at limited rpms for quite awhile. As a result of following everyone's instructions, I was unable to check to see if the engine could make full rpm at the suggested prop setting. So the clutch was destroyed within the first hour of run in time. The problem was not just weight but rather the prop's moment of inertia (MOI) exceeding the engine's MOI limit. My order is now in (to a new vendor: E-Prop) for a replacement specified for my engine. In the meantime I will rebuild the clutch. But the real issue is trying to get either the engine manufacture or the prop manufacture to divulge their MOI information for any given engine or propeller. So unless you know you are using a prop that is compatible with your engine, I suggest that a new engine is run-in with a very "fine" prop setting.

[@alanswanson1952]

I think you did a great job

[@bonza007]

Good lesson in props, thanks mmatt!

[@quieteagle1656]

I like it when I learn stuff. Mr. Piper pitched plenty of props on Piper planes to produce plenty of power so he wouldn't plummet from the sky. That would have been a problem. I could go on. Don't know how you got through all those P words without getting tongue tied. Good show Matt. (smiley face here) but I din't know how to do that on this thing..

[@mmatt]

It took a few takes. LOL

[@jonray1434]

Matt how about a video on different engine brands available with pros and cons? PS really have enjoyed your videos!

[@dennisflemming826]

Great explanation mat : from the air foil point of view; ie max lift min drag ! However all foils also displace air ; size for three bladed props displace air better than two , in a tractor config the displaced air causes extra skin turbulence. None of this can be looked at alone , its more a case of a little bit of Column A , a little bit of column B and some column C , don’t forget D and G . Project Scrapie has a displacement prop , EXTREME. On your other point the three bladed prop doesn’t have another blade at 180 degrees to create harmonic resonance , 3 and 5 smooth, 2 and 4 noisy , subject to shape compeziton and outside influences like skin turbulence in the case of a pusher , don’t get me wrong, not an expert ether , cheers buddy love your show, keep it up

[@dandil]

3 bladed props are smoother because they create a higher frequency of air pulses at lower amplitude. The higher frequency means less coupling since it's further away from the resonant frequency of the air frame.

[@jjohnston94]

3 blade pushers run smoother than 2 blade because there's a thin layer of faster air coming off the trailing edge of the wing, and with a 2 blade prop, both blades are hitting it and interacting with it at the same time, every 180° of prop rotation, whereas with a 3 blade, only one blade at a time is, and every 60°. But there's probably also some truth to those other things, too. And for an interesting story, look up the man behind IVO props, Ivo Zdarsky. He built an ultralight to escape from behind the iron curtain, and today lives alone in a hangar in the ghost town of Lucin, Utah.

[@davidrobins4025]

Another informative video. Thanks.

[@jimsandoval7633]

Great video, I learned things I didn't know I did know . Thank you.

[@markconnolly692]

Hi, I loved this video! I was always a little confused about propellers, and your video on propellers has lots of good info, but sadly I may be even more confused now. Anyhow, thanks again, and I just wanted to say my mom is a Canadian.

[@mmatt]

Feel free to ask questions and I'll do my best to answer them. My mom is also Canadian... :-P

[@rickybailey7123]

Cool video I didn't know all that thanks for taking your time to do that keep making them I try to watch all your videos they are just what I would love to be doing so I'm living thu your videos !!

[@rickybailey7123]

Where is the best place to buy a adjustable 3 blade prop for a 50 hp engine? And can u buy them used ?

[@f16bmathis]

Prop balancing... where can I get a tool, Mandrel, to balance my own prop, plus how bad would an out of balance prop be? I think I'll have to make one. Great video's, subscribed and like them all!

[@mmatt]

You'll probably have to make one. That's what I had to do. Glad you enjoy the videos! :-)

[@kiesha104]

Matt. Im retired Army who just moved from neighboring NY to SC. I have a small Airport aboot 10 min from our new home.... " ABOOT"...😉 What is the weight limit on most Ultralight aircraft??? Love your videos..

[@mmatt]

Hahaha, yes, I'm definitely Canadian. :-P If you're talking the US Part 103 definition of an ultralight, most can carry at least 250lbs (Kolb FireFly) and some as much as 365lbs. (Aerolite 103)

[@kiesha104]

@@mmatt Being raised just outside Buffalo NY, I've had my share of trips to Tim Hortons. I'm pretty sure I'm 0.08 % Canadian by coffee intake alone.... Enjoy the sky....

[@rogerolander458]

@@mmatt Matt this is not correct. The last time I looked at part 103, (five minutes ago) the empty weight limit is 254 lbs. But, except for seat belts, instruments, etc., safety items are excluded from the empty weight requirement. So, if you add a 24 lbs ballistic recovery chute to your part 103 aircraft, it can weigh 278 lbs. At 365 lbs the Aerolite 103 would not be legal.

[@mmatt]

@@rogerolander458 I think his question was asking how much an ultralight can carry, not much it weighs empty. I was listing the useful load of those planes, not how much they weigh.

[@rogerolander458]

@@mmatt AHHH, - OK. I didn't read it that way.

[@davestelling]

Excellent job, Matt. Happy 2021!

[@MarkLoves2Fly]

A higher blade count, will induce a higher frequency pulse on the affected surfaces. Many times this is above the resonant frequency of that surface, so you will notice less vibration. The down side, is that more blades, means more drag, so the engine must work harder if the diameter of the propeller disk is the same size.

[@trottpark]

Thanks for the info re: props I had no idea, I have a couple of ?? mmatt what is the brand name of those outboard wing tanks you have on your plane, second ? is that RR bridge that you & Vicky flew over the day you had trouble with your starboard side snow slippers, was the bridge C.N or C.P. you in Canada ? put it this way you sound Canadian. Cheers from OZ

[@anthonynastasi2022]

nice job

[@patrickmckowen2999]

I was enjoying the vid right up to the point where you started talking about propellers 🤣

[@MrHanowski]

Well done! Just a comment that a digital protractor will give more accurate pitch setting results.

[@gillesallain9565]

Nicely done man!!

[@camaramehdi815]

Hi I'm verry happy for your jobs

[@701theboop5]

Great Video Matt, the Prop on the Boop is Ground adjustable but acording to my Max Rpm on the Rotax I am getting 5800 so I should probaby leave it alone.. More speed would be nice but Im probably getting all Im going to get.??.Down River Tim (Oak Point Area)

[@mmatt]

You should be getting 5600 rpm in straight and level flight at full throttle. If you're getting 5800, you're set up for STOL operations. If you're ok with losing a little bit of climb performance, you could pick up a few mph by putting a bit more pitch in the prop to give you a faster cruise speed.

[@701theboop5]

@@mmatt Thanks for the info Matt. I like having the STOL performance and my speed straight and level at 5200 rpm is 75mph with the floats on. I may gain a little speed by re-pitching but with the floats on I need to keep all the climb I can get lol. I am super intrested to find out what my level flight speed and climb is with the snow skis on if the pond ever freezez to give me a runway to take off from..Im fueled and ready to go just need some cold weather..

[@plywoodcarjohnson5412]

Great video, thanks. Why not a fourblade?

[@mmatt]

The more blades you have, the less pitch you need. The less pitch you have, the slower you go. It's a balancing act and 3 blades seem to work best for this size of engine and airplane so that's what most of us go with.

[@scottmorrison9149]

Thanks!

[@ZeroGMVideos]

hi Dude! as you are a big fan of props.. do you know the diference between "straight blades" and "curved blades" ? its about drag.. sound..? Thanks!

[@mmatt]

I didn't know the answer off the top of my head so I Googled it and found this: hartzellprop.com/why-choose-a-scimitar-propeller/

[@alemoncada]

great stuff Matt. So what's the best prop for a Eurofox (european version of the Kitfox) with a Rotax 912 ULS3? I'm getting the plane in september and I have to choose and I don't know what's the best. I'd like a constant speed prop but is if going to weigh too much? Is an adjustable one better? I'd like to have STOL features but fly at 110kts. How do you make the right choice you know? And what if you screw it up completely?? choices choices choices Thanks for sharing

[@mmatt]

If you want a less expensive in flight adjustable option, consider the Ivo prop. I like them.

[@TaxpayerDave]

"at first there were 2 blades. Then came 3 for a smother stroke. Then there were four blades. When is it going to end? Now.... the ultimate 5 blade razor errr propeller."

[@mmatt]

Well I was going Mach 3 yesterday.... no wait, I was shaving with my Mach 3. Close enough. lol

[@dtuer]

62" ivo prop, good stuff

[@lucywucyyy]

ive always wondered if you could have a 4 bladed prop where two blades have a fine pitch and two blades have a course pitch, my theory is that way youd get good takeoff performance and cruise performance without the complexity of a variable pitch prop, but i wonder if maybe the extra drag would cancel out the benefits, either way theres probably a reason why this isnt a thing thats ever been done (as far as i know) but i think itd be interesting to try

[@TaxpayerDave]

no that is a horrible idea. think of it like having a car that has two motors, one for the front wheels and one for the back wheels. And the two motors are trying to turn the front and back wheels at different speeds.

[@lucywucyyy]

@@TaxpayerDave some cars do exactly that lol

[@rickybailey7123]

Where is the best place to buy a adjustable 3 blade prop for a 50 hp engine?And can u buy them used or only new ?

[@aviation1036]

Just a quick question!!! How you like Ivo propellers ? I’m thinking to change mine on my ultralight… I’m currently have a warp drive but I have a lot of vibration at 3000 rpm

[@mmatt]

IvoProps are good... but I'd look into an UltraProp II. I just got one and I love it.

[@ia6980]

Question please, if my propeller changed from 7.8x8 to 7.7x7 how would it affect thrust and speed? Will greatly appreciate

[@MrPetrvershinin]

so, my comment did not like and it was removed! a different look at three blades and two blades without changing the angle of attack: a three-bladed propeller creates a smaller pressure difference in front of the propeller and behind the propeller (the pressure is less in front of the propeller, the pressure on the rear surface is greater AND THE DIFFERENCE OF THESE PRESSURES AND CREATES the pulling force of the propeller), this creates the effect smoother operation of three blades Больше

[@codraven57]

So Matt, what happens when the propeller is fixed and and the airplane is rotating and is the air actually moving over the propeller or creating lift over the airplane? How much bite is involved in this situation?

[@mmatt]

You had me trying to picture that for a few minutes... There's some bite of course.... but it involves you and my arse! :-D LOL!

[@codraven57]

@@mmatt Good one!

[@lucywucyyy]

i wonder if the two vs 3 blade balancing thing is to do with gyroscopic procession, thats my guess

[@newfgoofy2]

Thanks for the excellant info. I've been thinking about adjusting my prop on my Hawk, and now I know which way to go. Also have a question on how you are running the fuel line from the your wing tanks. I'm about to do the same but wondering if you are running to the main sit-tank or directly into the fuel line to the engine. Also if to the tank where are you connecting the wing fuel lines to the main tank. Thanks ahead of time. Enjoy your videos. Newfygoofy2

[@mmatt]

My wing tanks feed the engine and my seat tank feeds the wing tanks. Each wing tank has an on/off valve so I can keep the tanks balanced in case they don't feed evenly. Here's a video of the set-up: kzbin.info/www/bejne/pp7FpnZvbtiNo80

[@newfgoofy2]

@@mmatt Thanks. Did think of reversing the flow to wing tanks. Keep punching holes in the sky.

[@reelflyt]

Is that a Northwing Trike in the background with the 582 on it ?

[@mmatt]

It's a Northwing wing, but I don't think it's a Northwing trike.

[@scottyheflin4532]

Using this info for airboat

[@robertparadis6840]

👌😃👍👍

[@Tommy-B.]

I just realized as I’m laying here with the video on as I fall asleep, that with my eyes closed you sound a lot like Tom Sellek. Lol

[@mmatt]

Just wait till I get the Ferrari and the striped helicopter!

[@prof.heinous191]

As you know I've long been a fan and was propelled to this video by your thumbnail, but my advice is never try and use a thumbnail as a propeller, best to put them in the bin with the other clippings.

[@mmatt]

You win. lol!

[@prof.heinous191]

@@mmatt Seriously, that was a very good talk!

[@class2instructor32]

Com'on Man! "Not an expert!" Your a pilot! You of all people know we ARE experts on absolutly everything. We just dont like to brag.....cause we're known to be humble like that!

[@class2instructor32]

Also Hahah "Fan".

[@mmatt]

:-D

[@mindlessconsumer]

matt, there is a good video about e-props propellors that explains why 3 blades are smoother than two for vibration. You are basically increasing the frequency of thrust at a given RPM, so the absence of thrust between props is less pronounced and the thrust is more consistent. kzbin.info/www/bejne/sH6YhINtjbipZ9U

[@camaramehdi815]

I need to know your if possible

[@jeffreygaberdiel721]

Lol. Refers to the Cherokee as “fast”

[@mmatt]

Compared to my ultralight.... it is! :-P

[@mrJety89]

Propellers are literally big fans

[@andrzejpl9897]

👍

[@salvatoremilitello8490]

this here is an air screw it screws air you see 3 blades is better cause more air screwing is going on! lmao

[@mmatt]

That actually sounds more along the lines of how I should explain it... :-P

[@russellsmith3825]

I'm curious what the engineers are thinking back in WW2 when they setup some birds with 4,5&6 bladed propellers

[@flyingkub]

That is a good question. The basic answer is props don't work it the tips go supersonic and the engines had a lot of power (over 1000hp), so to use a two blade would mean a very big prop (with a taildragger that would be hard to keep in the runway). The way they kept the tips subsonic was to have smaller (managable) diameter props and add blades, as you can't have the pitch great enough to absorb the power, as it would be stalled until the aircraft was moving at speed.

[@mmatt]

Well I'd say they were trying to harness some serious horsepower. More blades are required on more powerful engines so that the blades don't have to be so long.

[@flyingkub]

@@mmatt Is that not what I said?!?

[@russellsmith3825]

Would there be any benefit to install a 2 speed gearbox on the prop such as a direct drive/underdrive, or direct/overdrive so that you could keep the engine in the power band in different flight phases?

[@mmatt]

@@russellsmith3825 You could but it makes more sense to simply alter the pitch of the prop as it does essentially the same thing and is much easier and lighter to do.

[@scottyheflin4532]

Using this info for airboat