Everything about PROPELLERS! Size, profile, number of blades and MORE! Paramotor geometry part 29.1
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- čas přidán 23. 07. 2024
- Yes, we are back with the series!
It this series we are going to explain, why a larger prop is better then a smaller one! We are going to speak about every aspect of choice and design you have to make before choosing the right propeller!
Stay with us and you will find out, which propeller suits you best!
Topics that will be covered in this classroom:
*Please, be aware that we are adding videos each week, so there can and will be changes to this list.
1. Intro: Searching for the ultimate best paramotor - what is or will be your flying style?
2. Paramotor suspension, part 1: Why suspension is the most important characteristics of a paramotor?
3. Paramotor suspension, part 2: Why weight-shift is more fun and more safe?
4. Paramotor suspension, part 3: How much weight-shift authority you get from your paramotor?
5. Paramotor suspension, part 4: Pitch stability under power
6. Paramotor suspension, part 5: Speed bar behavior
7. Paramotor suspension, part 6: Ground-handling and running with a paramotor
8. Paramotor suspension, part 7: Comfort in flight
9. Paramotor suspension, part 8: The sectret questionmark suspension.
10. Paramotor suspension, part 8: The big comparison of paramotor suspension systems
11. Torque: Why and how much torque we face?
12. Torque: Why don't we use counter-rotating propellers?
13. Torque compensation on high suspension paramotors
14. Torque compensation on medium and low suspension paramotors
15. Torque: SCOUT Dynamic Torque Compensation.
16. Comparison of torque compensation systems
17. Gyroscopic effect on paramotors
18. Geometry of the paramotor frame, part 3: Why being reclined is dangerous?
19. Geometry of the paramotor frame, part 1: Why being reclined is inefficient?
20. Geometry of the paramotor frame, part 4: Big comparison of paramotor frame geometry
21. Harness geometry, part 1 - getting in and out of the harness
22. Harness geometry, part 2 -Why some harnesses are more comfortable than others?
23. paramotor safety, part 1: Load test of paramotors
24. paramotor safety, part 2: Attachment of the gooseneck bars to the main frame
25. paramotor safety, part 3: crumple zones and back protection
26. paramotor safety, part 4: Beware of getting the throttle cable into the propeller
27. paramotor safety, part 5: propeller clearance
28. How much power do you need?
29. Standard 125 cm prop or larger?
30. How much does weight matter?
31. Do you need a clutch?
32. Electric starter or manual?
33. How important is aerodynamics of paramotors? fuel tank hanging low
34. How much fuel capacity do you need?
35. What is the ideal paramotor for tandems?
Stay tuned! Did we miss something you want to learn?
Please, leave a comment...
Feel free to have any question at info@scoutparamotor.com
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Love these series. As a paraglider pilot of 10 years I'm new to paramortoring and I really appreciate you sharing your experience with us. Very nice! Much appreciate from Canada
Awesome video! I appreciate the time you took to put this together and give understanding to this very relevant information. Subscribed
The way you describe the science and math behind paramotors is second to none. Whenever I have a question and one of your videos pop up I know I’m gonna get really good quality information. Thank you, hopefully my third paramotor will be a scout!!
Thank You! Have been watching the entire series and find it really educational. Congratulations on the Iceland trip!
Fascinating stuff!!! Thanks!
I love learning the application of science in things. I don't fly yet but this has been really interesting and will be very useful later. Keep it up!
Very informative. Thank you.
I'm a huge fan of yours. Thanks for all these great videos. Much appreciated.
I really love this series! I have, of course, watched them all. Epic adventure in Iceland. Thanks Tucker...
I will be buying a scout soon, but it looks like you are getting ready to release a newer design. Should I wait? Ha ha. Thanks for the knowledge!!!
Welcome back! Great video as always. But there is still one more topic on propeller design: tip shape. I hear rumors that curved tips (sometimes called Q-tips) reduce noise significantly, and reduce vortex drag, but then the added surface area out there at the fastest moving part of the propeller increases regular drag, so total efficiency comes out about the same. Might be an interesting area to explore for a new and improved Scout prop. Think winglets on an airplane, except those usually curve upward for practical reasons (less chance of scraping on the ground or being run into by other airport vehicles). Curving down is probably better for a propeller, especially on a paramotor to avoid the cage.
Nice videos! Thanks for doing these.....very interesting and helpful!
Got to respect a person who favourably compares a competitors gear to their own
Great explanations, great vid
Great video. The title says part 28 but it should be 29. Part 28 was about how much power you need.
That's good heads up there Woody..What prop do you have on your 200?
Hey Woody, when are we going to get some more Paravlogs from you? Or at least a day in the life vlog. Geez, man, get back to work already!
Thanks!
Very interesting Thank you.
I'm trying to understand the length of the reach of your arms. If you are referring to applying pressure to the a lines, this is done at the riser. A larger cage would not change where your arms would be to apply pressure to the A's. The biggest limiting factor to cage size would be the length of the pilots legs and keeping the cage from hitting the ground or interfering with running.
yes, you are right.
you do not need to reach all the way to the cage rim.
Ground clearance is more important
Great series, thank you. Are there props with wing tips turned into the forward side of the prop? Where can I see a discussion of this idea?
Have good info BUT , it's called airfoil's, lift coefficient , etc. Tip shape has everything to do with efficiency/sound.
Static thrust measurements are critical especially when determining rigidity of prop.
I still give it a thumbs up!
Keep up good work....have subscribed. Recommended to my friends.
Thanks!
Hi Miro, good informational video. Can you tell me what is the pitch of your propeller that you sell with the Scout? Thanks
Very interesting, thanks for putting this series together. This may be a novice insight because I am a novice :) but, I was surprised that the static thrust test was not considered that important. I realize that getting the real world data on climb rate, for example, is a test that is going to be done anyway but, wouldn't knowing the thrust give you an initial indication as to whether the prop was going to perform better in climb rate, at altitude....?
Without any science to back it up...I perceive that in spite of how much prettier and quieter my carbon fiber prop is, my fat cord, wooden aerolight "beginner" prop, creates more static thrust at the near sea level density altitudes I typically fly from. It provides for better acceleration on take offs and a feel of a more solid push from behind. Throttle response (RPM) difference are minimal, but may be slightly quicker with the thinner lighter carbon fiber. Certainly the bulbous hump near the hub of the Helix provides for better engine cooling, but I am honestly thinking of just going back to the wooden stand by for the simple sake of PERFORMANCE.
That is really interesting to hear. Are you a representative for a wooden prop manufacturer, or have any financial ties to them, because it certainly SHOULD NOT be the case, from a materials standpoint alone. Like you say, though, it could be a function of your prop being targeted for sea level use where some others may not be.
Is it as "performancy" at higher speeds?
And what about MPG, or efficiency?
So with your 27hp monster Motor are you using 3 E blade? Since the monster is the second highest powered motor in the market. Thanks
Good prop primer, thx. That last airfoil is typically called an undercambered foil. I assume the "special manufacture" you speak of to allow the thinner foil section is the addition of, or modifications to an internal spar? Also, twist is another prop parameter that deals with aircraft speed, mostly, as I understand it, giving maximum efficiency at the economy cruise (or wherever specified) at cruise (or whatever) RPM. Correct me if I'm wrong.
I assume your planform profiles are computer "designed", or at least analyzed as well? Gorgeous prop, by the way, that new one, that is almost SEXY looking!
Probably MUCH too complicated for a paramotor, or even ultralight, but has anyone thought of making a automatic pitch changing (constant speed, or even just two speed centrifugally shifted) prop. I used to use them on boat propellers, and they were really the nuts when you got them dialed in. Weight not so much of an issue there, though. Probably wouldn't pay off for the increased complexity and weight, especially dynamic weight.
Dumb question: how come nobody specs thrust vs. speed, wouldn't that be a more useful spec, or does it usually just scale mostly linearly (I would think maybe not), although at these Reynolds numbers and pretty tight speed envelope, maybe so. Never mind, watching further I like your tests EVEN BETTER. Proof in the pudding, right? ;-)
Ok but how do you calculate the mach number to get the right one for your motor powerband?
Great series Miroslav. I'm glad you mentioned the Icarus Trophy. If I'm not mistaken there are 2 Scouts still participating in this years race ( 1 race, 1 adventurer class ). That has got to put a tremendous strain and considerable wear on an engine. What did you need to do to your engine after you participated last year?
Why in HEAVEN'S NAME should that put any excessive strain or wear on what is, essentially, an aircraft engine? You guys have learned to live with JUNK for engines. Typical aircraft engines (and bikes, and cars) go THOUSANDS of hours, and HUNDREDS of them between maintenance. Measuring engine life in tens of hours is NUTS in this day and age! If a company like Honda, or Toyota, or Rotax took this on, they would have REAL usable engines on your backs in no time, and honestly, I don't think they would cost any more than this garbage you are stuck with now. Just sayin', as an engineer.
@@MrJdsenior I would love Yamaha to revive their 350LC 2T engine in a small format, BUT it aint gonna happen. The overall market for paramotors means that the serious players arent interested, they sell more marine engines for example in one year than 5 years of paramotor engine sales. So we are stuck with modified scooter engines because thats all the market is worth. If any major manufacturer decided to enter the market then they would wipe the floor with the encumbents but they wont because there would be no profit or even a loss. Welcome to capitalism :)
And here I thought class was over! Happy to see you back to teach some more. By the way, you must be proud that your Scout paramotors are currently leading the Icarus Trophy race. I believe the winners last year were also using Scouts?
+SuburbanHobbyist me and Byron Leisek have won the adventure class on scout paramotors.
The race class was won by Dave Wainwright from Australia flying a nirvana paramotor.
Fact is attitude and wing selection are key factors for success in such race.
Wow, I didn't know that, very cool.
Thrust is important, but speed is also important, and large propellers have a strong degeneration of thrust at airspeed.
Your tutorials are fantastic! Thanks for doing them. I’m an aspiring paramotorist. You mention a couple if times if the prop was a bigger diameter you’d need long arms to be able to reach. Why would the hang point width change with a larger hoop? Just curious
I was referring to forward take off when you spread your arms to pull the risers. But in fact the cage diameter does not matter, the lines will slide along the cage regardless of the diameter
Could you put winglets on the tip of the prop to gain more effective thrust area?
Yes, but there are trades and compromises all over the place. Not a simple thing to do or design. If you look at some general aviation and ultralight props, you will see some manufacturers have done this.
The e-blade(thinner) seems it might be more efficient, as I reflect on a Canard wing being more efficient giving more lift to less drag.
How does this logic work when the general idea of a 3 blade prop is that it produces more thrust but is less efficient?
So, I know you have considered this, but a ducted fan is way more efficient than a free prop, and all but eliminates the tip vortex problem. Clearance must be very close to the blade tip, and frame flex would probably be an issue. Weight, rigidity, etc... Any thoughts?
hey guys, any idea how much different the thrust value is if airspeed is 5,10,25,20 mph?
Would a prop tip design, such as the one used by the new DJI Mavic Platinum drone, help with PPG noise and performance or is it even possible to mfg.
+Kevin I do not know.
It is possible to manufacture.
Not sure about the benefits
Sir 1984 Kolb ultrastar aircraft What is the length of the propeller ..
Aircraft wings have winglets at the tips of the wing. Similarly, have you considered proplets to increase efficiency or reduce noise? This would be a fun FEA analysis.
could be. we did not experiment with this yet.
Grabbing larger volumes of air is more efficient also by the consequence of conservation of momentum and conservation of energy.
For the same thrust you waste less energy to speed up the air.
Same laws make turbofan more efficient than turbojet (at least at subsonic speeds).
How much more rpms for level flight between 125cm and 130?
Miro, I know this is an old topic, but still one of great interest to me. May I ask which 3 blade prop you used to compare with which 2 blade to conclude that 3 blade offers no increase in thrust? (ie:130 cm-3 vs 132 cm 2) or (125 cm 3 vs 132 cm 2) -etc. I know the results you obtained are subjective, but I would still be interested...
It was our own development. Never put in the market
Would love to see the SCOUT fit a 140cm prop
static thrust is not useless at all- I feel it on the ground how much i need to take off with a trike- very easy to feel the differences...first comes the take off before anything..
Fixed parameter you didnt highlight is the motor stators and kv/kt and ofkos the fix loads for paramotor i.e. one man on metal frame. If those changed to lighter, smaller or more compact, the motor used may vary and the props selection is different. E.g. a monocoque carbon fiber with multi rotors. Should smaller footprint design is viable, the (your) design rule is obsolete.
In one of your videos you mention that you think Vittorazi makes one of the best engines on the market, but in your opinion, how does the Polini Thor 190 compare with the Moster Plus 185? Also, why is the Polini so much more expensive? ~$1000.00
+Richard Kaminski the moster plus is more expensive.
We had reliability issues with the polini 190...
@@SCOUTaviation Who are you kidding? EVERYBODY has reliability issues with ALL of them.
Flat end tips like e-prop propellers or rounded tips like the rest of propellers?
Theoretically flat end might be better.
Theoretically the difference is minimal.
We did not measure so cannot confirm.
Flat tips are more prone to catch the lines
More blades are generally less efficient due to interference between the blades. the ideal prop has a single blade but the added weight of a useless counterweight makes the ideal real prop a 2 blade. Also, it's not the mass of the prop that determines the responsiveness, it's the moment of inertia, which has to do with diameter, mass and mass distribution. You can theoretically get a lower moment of inertia with more blades, gaining responsiveness at the cost of efficiency.
Yes, it is true that a larger propeller can generate more thrust, however, it also leads to more strain on the engine. So long terms effects may not be good....
No it does not if done properly.
Increase in diameter is always accompanied by decrease in angle, profile chord or change of profile shape to keep the strain the same.
Would you just increase the diameter and keep everything else the same, the engine would be under increased strain and it would not be able to reach max RPM as desired by engine manufacturer.
awesome video, this was super helpful during my Prop shopping. One question i have that you didn't touch on specifically: you mentioned 3 blade props don't produce more thrust than a 2 blade prop which sounds like it would be true, but i'm assuming the test in which you concluded this was done at full throttle. I have heard elsewhere that a 3 blade prop can produce more thrust at 1/2 power than a 2 blade prop could with the same amount of power, therefore you could cruise at a lower RPM. Anyone have any knowledge on this?
How can a circle be a square function? Area of a circle isa multiple of 3.14 pi?
"The area of a circle is pi times the radius squared (A = π r²). Use this formula to find the area of a circle when given the diameter." The diameter is also twice the radius if given that.
@@ullrsdream how long is a piece of string? Twice half of its length...
Does the prop material matter? I think carbon fiber's better than wood, right?
Carbon allows lower profile heights (thinner blades) which tent do perform better.
Carbon shatters into small particles, wood shatters into spears and arrows shooting out due to centrifugal force.
Thanks very much for these,as a nigerian i am sure of success because i am developing a personal triker airplane.I am sure of success thanks a lot.Hoping to contact you .
Sir i want to buy propeller ..
Eshop.scoutparamotor.com
Is it a parameter? Or is it a paramotor? X-D
+F!@#Guilt glad you have figured it out.
Love your videos btw! They've taught me alot.
Boom. Like number 200... which means absolutely nothing in life, but what the hell.
Remove the pesky prop tips for more efficacy. 😂
Actually, there is a way to do that, to a small extent, it is the equivalent of winglets on an aircraft wing (look at most large commercial jets if you don't know what I'm talking about). They essentially "unwind" the vortices, and effectively increase the usable span of the wing (or blade). NEVER something for NOTHING, though, always compromises involved.
You lost my attention when you said you never check static thrust. Why not? Its what everything is all about. You are just trying to sell your product and that's not interesting at all
I am sorry for losing your attention because the answer to your question is later in the video. Shortcut for you: what matters is thrust in flight and there are ways to measure it.
In the world of racing, what matters is your trap times, not a dynamometer slip. Miro is taking the same logic, your climb rate is what matters, not your paramotor dyno thrust test. I think the solution is to use both methods of measurement here.
Boom. Like number 200... which means absolutely nothing in life, but what the hell.