Carbon fiber props

[ThunderChicken]

Okay, I stand shamed and chastised.

 

[PatR]

Don’t be that, just have some fun with researching propeller development and applications. It’s pretty interesting stuff once you get into it.

Something we always need to keep in mind is that companies are always looking for a means to incite people to buy their products. What often sounds really good in advertising often turns out to be false, or very exaggerated. But if it sold product, what the heck. Without detailed test data, performance claims are usually not worth the paper they are printed on. If there was no paper used... individual user claims are always suspect because they don’t do enough, if any, baseline reference testing to make a comprehensive comparison.

The average square or round tipped prop is typically not very efficient but good performance improvement can’t be obtained without tailoring a prop to a specific motor/engine/airframe/weight/flight profile combination. As a friend likes to say; you can generate lift/thrust with a barn door if you spin it fast enough[emoji6]

 

[John Hennessy]

Hi All,
This is a very interesting topic as I too was interested in changing props. Got CF from Carolina Drones and are quiter but no advantage anywhere else that I detected (7 days of tests and no difference) . However I had a relative try and achieve a better propeller for our H 480 at considerable time and effort as an assignment for avionics s engineers there conclusion not worth the time and money. On another site this same subject came up for discussion and a member on there that had significant input to the development of YUNEEC TYPHOON H 480 _______ 520 and H plus saidd that the standard props are
Carbon impregnated plastic designed to shear off under load so as not to damage the motors when an obstinate is encountered. The cheapies that are on ebay ( a red set I purchased for orientation purposes for the front two motors) are inferior plastic and no good ,I can vouch for that ,a heap more payable and flex alot so got Strobon Cree lights front and back and still use standard props that I balance with the use of clear tape ( they don't require much , as stock are very well made) and still use them now and am very happy with performance. When I found out the way they were designed to break near the hub so as to not over load the motors I was sold and stayed with standards. It is you choice if you want to try them out,if you are near Brisbane Australia you are very welcome to try mine and evaluate for yourself. Johnno Hennessy.
Keep flying on the green side of the grass.

 

[Bjpilot955]

During the early days of aviation engines were relatively weak so a short two blade prop was enough to handle the available power. As early engine development progressed props were changed from wood to metal to better deal with combustion pulses. During WWII engine development increased rapidly, creating engines with enormous levels of power. To use a two blade prop required the landing gear be extended to lengths that were not suitable for the stresses that would be generated, and cause aircraft AoA to increase to the point there was not enough elevator authority to allow a plane to take off, and safely land. The same situation became applicable to Reno Unlimited air racers as they further increased engine output, causing them to adapt wide, 4 blade C-130 props to make effective use of the power without being so long they hit the ground. For a little more propeller development history look up the development of the F4U Corsair and learn why it had “gull” wings.

As for being condescending, I most certainly am not. Your reference to the C-130 prop upgrade was amusing. Not just for those that have been involved with aviation most of their lives, but also for those that have flown in those 130’s and spent plenty of time in conversion with the crews.

For you it’s all guesswork and grabbing at straws hoping for minimal gains to offset the money spent. Others have real life experience and know better. Many times I have switched from a two blade to a three blade prop in aero modeling endeavors. Without fail there was a performance loss in one or more aspects in propulsion function. And all that was when using engines with considerable levels of excess thrust, something a Typhoon H has none of. The study of propellers to obtain more efficiency, thrust, and noise reduction has been a major focus in the UAV industry as those platforms absolutely have to be stealthy and extended mission duration is a very big deal for long duration. With the exception of a few high altitude models they’ve retained two blade props, most of custom design.

I am fairly new to this forum and thus far have been an observer and have chosen not to interject my personal opinion, especially in topics I am not well versed, that being said, I can definitely see why ThunderChicken felt you were condescending to him, you don't think telling someone they are making ignorant statements is condescending? There are other ways to educate rather that talking down to fellow posters! You seem well versed on general aviation101.perhaps a brief discussion on adjustable pitch props might be in order.
Bob commercial ASEL and part 107

 

[PatR]

Ignorance is a lack of knowledge and understanding. Because a descriptive word sounds rough does not make it inappropriate. Go onto Wall Street without knowledge and experience and start telling people what stocks to buy and why and you would be found ignorant (and likely broke) in very short order. Look up the definition of the word instead id reacting to the sound of it. There are many things in which I too am ignorant.

You can take up the adjustable pitch prop band wagon. When you find one that is affordable and effective for multirotors, let us know. They were employed on the full scales I flew. When you get started be sure to break out the differences between hydraulic, electric, and fly weight actuators.


Pat
Just to get it out if the way;
Commercial, single and multi engine land, instrument, CFI, BGI, Part 107, mil level UAV operator/maintainer certified.

 

[Bjpilot955]

Ignorance is a lack of knowledge and understanding. Because a descriptive word sounds rough does not make it inappropriate. Go onto Wall Street without knowledge and experience and start telling people what stocks to buy and why and you would be found ignorant (and likely broke) in very short order. Look up the definition of the word instead id reacting to the sound of it. There are many things in which I too am ignorant.

You can take up the adjustable pitch prop band wagon. When you find one that is affordable and effective for multirotors, let us know. They were employed on the full scales I flew.
Pat
Just to get it out if the way;
Commercial, single and multi engine land, instrument, CFI, BGI, Part 107, mil level UAV operator/maintainer certified.

Does your arm hurt?

 

[Bjpilot955]

Ignorance is a lack of knowledge and understanding. Because a descriptive word sounds rough does not make it inappropriate. Go onto Wall Street without knowledge and experience and start telling people what stocks to buy and why and you would be found ignorant (and likely broke) in very short order. Look up the definition of the word instead id reacting to the sound of it. There are many things in which I too am ignorant.

You can take up the adjustable pitch prop band wagon. When you find one that is affordable and effective for multirotors, let us know. They were employed on the full scales I flew. When you get started be sure to break out the differences between hydraulic, electric, and fly weight actuators.


Pat
Just to get it out if the way;
Commercial, single and multi engine land, instrument, CFI, BGI, Part 107, mil level UAV operator/maintainer certified.

I give up, I am ignorant compared to you...I will leave with a little philosophy, " man that toots his own whistle so loudly, often is off key"

 

[PatR]

You’re the one that tossed certificates in the hat. Truthfully, should people expend the effort writing multiple sentences to avoid possible irritation when a single word is accurate in saying the same thing? Reality is tough and something we all have to deal with.

 

[AveryBadman96]

I have thought about all of these scenarios as well. I fly racing drones with 3 bladed props for decreased noise and increased lift with the only drawback of less flight time due to drag on motors and battery time. I'm not sure comparing propellers in water vs an aircraft propeller is an accurate due to drag, thrust, etc. Otherwise we could convert a boat motor into a aircraft propeller. I'm a helo pilot, but I admit I don't know much about water propulsion. I do know a helicopter blade wouldn't work in the water though for propulsion.

 

[Brett]

Hi Dustoff, I would not use carbon probs, they maybe a little quiter and may give more stable flight BUT the downside is if you hit a tree och something like that you might ruin the motor and/or break the arm itself. Or even cut your fingers.. by this razor sharp high speed carbon probs. I prefer to chose the less expensive way to break a plastic prop and save the rest.

I ran a set of carbon fiber props, got half the flight time, overheated the motors. The one time i ran these not good ill stick with stock props.

 

[Eagle's Eye Video]

Why anyone ever gets butt hurt from a posting on an internet forum, I'll never understand... condescending is the perception of the reader... and frankly I have seen PatR consistently back up his POV with real world experience and information. I would personally not be anywhere near as versed in this hobby were it not for the contributions from the regulars on this board. I'll take PatR's shoot from the hip, no BS zone posts any day... even if I have to take a nap after some of the more verbose ones...