Why this propeller is different: Airmaster Propeller on the DarkAero 1
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- Опубліковано 29 чер 2024
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We just received our propeller from Airmaster Propellers that we will be using on the DarkAero 1 prototype. The three blade propeller is constant speed and electrically controlled. It's specifically set up to work with the UL Power UL520iS engine on high speed aircraft. In this video we talk more about the propeller and some of the aspects of its design and functionality.
UL Power UL520iS Engine: ulpower.com/en/engines/ul520/...
Airmaster Propeller: www.propellor.com/ap533ctf-sn...
Torque wrench used to tighten blades - amzn.to/2LwFPev
If you enjoyed this video and would like to see more of this type of content, follow along as we work to create the fastest, longest range aircraft you can build in your garage!
More information on DarkAero can be found on our website and other social media accounts:
www.darkaero.com
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just amazing! your Grandparents were such good friends of mine, they would be so proud of you guys. Grand mother Carol was a pretty good pilot to boot i flew with her a quite a few times and i was impressed with her abilities considering her limited amount of time. Getting a ride in that plane has to be on my bucket list. I have no doubt it will be the new benchmark in aircraft.
Thank you Bob! That’s awesome to hear that you flew with Carol! It would really be fun to have the grandparents see what this is turning into.
I rarely end up commenting on videos but honestly this is such amazing content. I'm halfway in my engineering degree and your deep dives into the different components, processes and techniques you're using to put together DA1 is helping me learn more and stay motivated and inspired. So cool!
Great info. I am going with the Airmaster prop on my build and I'm glad you went into so much detail. Thanks
WOOOOOO I love these videos! Better than anything on tv! Keep up the good work!
Thank you for sharing and teaching us!
Thank you for watching! Glad you are enjoying the videos! 😁
Great explanations of how a constant speed prop works and how this prop installs and operates. Impressive.
Slip rings are awesome! Super interesting method for keeping electrical connections in a rotary application.
Using something similar that is custom made out of a pcb for making connections to a 3d printer hot end without having a wire loom. The slip ring your propeller assembly uses is non linear, my 3d printer uses a linear slip ring or a slip strip 😁
Awesome pitch control system and video!
Quick observation: I'm not sure if those 5557 connectors on the back of the controller are rated for high vibration environments as I don't see a locking feature to keep the terminals in place. You could look for automotive or aerospace rated versions, these have both connector and terminal locking features to keep the connection secure in high vibration. An example with similar size to the 5557s shown but terminal and connectors locking is the TE Connectivity MULTILOCK Connectors.
Thank you, very thorough and well explained product demo video.
Very impressive and professional, as always. I'm wondering about protecting the slip rings from dirt and damage etc.
Thanks guys for the info on the Airmaster. I'm building an RV-7 and have the same engine and prop. I didn't unbox the prop yet, but from what I can see in your video it looks great.
Great stuff guys, I just found the channel and really enjoy your detail and professionalism. I'm sure you've answered this a thousand times, what is the target speed for the DarkAero 1?
Hey there, check www.DarkAero.com for all the details.. btw 275 mph... (240kts)
I think this is the best presented aircraft related video I have seen in a long time, or even ever! And I'm not new on UA-cam.
Thanks for this very insightful content!
Glad you enjoyed it!
That's a wicked cool prop and even more impressed they are using a servo control vs. the age old mech/hydraulic control. I am also fascinated with their choice of brushes on the ring. Do the brushes and ring have a fixed lifespan? Interested to see how they wear in and what the life is.
btw, Still working on that Power Drawbar....
Really cool video showing off some amazing tech! I'm curious about noise levels at cruise given the high-ish RPMs. Do you know how these props behave (i.e. sound) at cruise configuration? Keep up the great information, thank you!
Excellent explanation of how a constant speed prop works.
the way you explain things and always give some kind of context about what you explaining is very pleasing. you could be a instructor or teacher and would be very effective.
Merry Christmas you guys and hope the new year will bring the best for you, you guys are the best
That's an impressive bit of hardware!
You guys are living my dream
Love that electric governor. I’m becoming more and more of an experimental category fan every day.
Very cool - can't wait to see her fly! Maybe Ill hit the lottery and able to put a pre-order in!!
Oh man ,I was waiting for this video
And hey ,marry christmas to you and family and friends as well .
Merry Christmas!
@@DarkAeroInc 😉
Informative & interesting!
I would look into change out the aft bulkhead to aluminum, the heat build up from engine and shaft will cause the epoxy to soften and spread out causing the prop to loose torque. This was big problem with canard aircraft ( cozy IV ) I fly, it might be different in the tractor configuration but something to consider. But great job on the airplane love the videos keep them coming.
Hi Ken! We are familiar with that issue you described from the canard community but I had heard it was more to do with torque pulses from the engine causing the prop to rub against the spinner backplate and generate heat which softens the backplate. Don’t know how much truth there is to this as a root cause but the end result is still documented. This was something we brought up to Airmaster in our early discussions and we concluded we could get our composite backplate to work based on their experience. We also consulted with some other spinner manufacturers who use composite backplates successfully. The epoxy we use is high temperature capable which provides some safety margin against engine heat. BTW, is the really pretty blue and white Cozy yours?
@@DarkAeroInc
Yes it is, thanks for the compliment. I didn’t realize the heat was coming from movement I always thought from the shaft. Thanks for the follow up, I learned something new. Do you still have your cozy or did you sell it?
Beautiful prop, high aspect, carbon fiber, high speed sweep...water-torture background music. Hope you guys get every knot you designed for, and more; I'd love to have a DarkAero1.
fantastic! is there a video where you layout the mainlines of the project?
wow.. nice prop.. but are there mountings for strain reliefs for the wiring coming out of the brush assembly. how about some kind of sleaving over the harness too.. are the connectors over the cylinder head water proof or just shrink tubed ?? i think back to a friend DC7 with electronic prop feathering.. it had a short that would kick up once in a while and blow a fuse in the instrument bay. creating a flat prop . not a good thing to happen at climb out. i wonder if there is a resistance test circuit to the prop motor that when it becomes iffy thru the wiring. brushes to contact plate or in the feathering motor.. that it would signal on the dashboard display with a failure mode. something as simple as a rasberrry chip to monitor the resistance or voltage and ground.. i don't want to sound like a safety sally.. but i am a mechanic and i have seen way too many electronic devices fail.
There's a few things I noticed that concern me to.
nice work
Thank you for sharing your process! It’s inspiring to see what a three person team can create.
You are getting this wired, dude! Looking forward to flight testing!
Great work guys
Μπράβο παιδιά εξαιρετική δουλειά!!!
Thank you dimitris!
Ooooooh, I think it’s going to sound great!
Ur dark aero reminds me a toothless from 'how to train your dragon' ammmazing!!! U guys are proficient in ur work.
Have to say complete work of art. No question this is a very nice and thought out build. Is there a plan for production although i can't imagine the cost will be astronomical. Can't wait to see the finish product. Do we know when would that be?
Superb. Great work folks. Good luck with that pearl of a set-up... xxx ;-)
Congrats! I am a Brazilian Sport Pilot and experimental aircraft amateur builder! I teach advanced composites at local post grad Universities! Well Done Guys!!!
Merrrry Christmas! Best present ever!
Merry Christmas Richard!
merry christmas , damn you guys testing all of us with propellors we want to see this art flying❤️
The WWII B-24 used electric propellor pitch control. Part of the pre-flight process was starting a little piston-powered APU, to keep the electrical system charged up despite the load imposed by starting 4 big radials. If the pilot didn't do that, it could become impossible to increase the prop pitch after takeoff. The motors would likely overspeed, leading to a generally Bad Day.
The B-24 was mostly hydraulic, with electric pitch control. In contrast, the B-17 was an electric aeroplane with hydraulic propellor controls.
Having more than one type of control mechanism helps prevent total system failures.
Wow. Your 10 minutes video felt like a 5 minutes video. I guess I was hungry for more DarkAero built.
😁 Glad you liked it! More videos coming soon!
very nice Brilliant presentation
Looking at the thumbnail and title of the video I'm wondering if the reason Reilly has his hat on backwards, is for speed purposes as well? 😂
Very strange comment but... That threaded collar to attach the blade to the hub looks incredibly satisfying to tighten. I can just feel the thread engagement through the screen.
The HOLD function is like the pre-set TO, CLIMB and CRUISE modes but is able to be customised. When Hold is selected the unit will remember a manualy adjusted setting when, for example, the selector is switched from Hold to Climb and back to Hold. The memory only lasts during the flight and is lost when powered down. There is no need to select manual on the rocker switch to use the Hold function, just select Hold and use the fine/course selector. At least this is how mine works fitted to our 912 Rotax. Brilliant product!
Progress is looking good, keep it up and you'll be done before you know it!
Thank you!
Very interesting demonstration on the propellor. Is there a range (up and down) for arrows and more or less powerful engines?
I've worked on Turbo props so I'm not 100% sure about recips... The bolts you have in the video don't seem to have holes in the heads for safetywire. Safetying the flange bolts is one small step for a lot of security. I'd hate to see that prop go missing in flight someday! Another tip: While the grease is coming from the factory it's often cleaned out and replaced anyway just to ensure no cross contamination with your grease which may or may not be the same as what they claim to use.
Great video, I’ll need to rewatch it a couple more times so I can digest all the information. Cheers.
So many decisions made about your prototype are minimalist, with the idea of less is more... So, it's fascinating to see an engineering choice where a bit of 'extra' weight and complexity is worth the improved efficiency. Similar logic to retractable gear... extra stuff that makes the aerodynamics worth it. Your design choices seem great so far, I can't wait for you to start testing them! Cheers, and thanks for another great update!
Exactly! Less is more! We started off looking at a fixed pitch propeller under this philosophy, but since we have a new airframe and engine combination, we knew there would be some iteration required to get it right. The variable pitch solution is a faster path to hitting our target performance numbers. There is still a lot of appeal in a fixed pitch propeller (lower weight, cost, and complexity) so hopefully we can use the lessons learned with this variable pitch propeller to drive the design of a fixed pitch propeller for the DarkAero 1. Thank you for watching! More updates coming soon!
@@DarkAeroInc The theory sounds great! With the support from the prop and eng manufacturers it seems to be a great solution. Were you able to de-rate or downsize the power plant specification because of the increased T.O. performance of the variable pitch?
@@DarkAeroInc are you still considering designing a fixed pitch solution once the prototype is flying?
Personally, I would prefer a fixed pitch propeller, even if the max speed is slightly reduced. While this propeller is really cool, the number of moving parts and the cost makes me a bit concerned. I think the DarkAero 1 would look pretty cool with a Prince P-Tip also.
@@DarkAeroInc Since you have specific blades chosen, you presumably know the weight of a fixed-pitch configuration with the same blades. Do you know what the weight penalty is for the constant-speed version?
Merry Christmas ;)
What a cool video!
Isn`t the best economy of the engine at 2400 rpm? Is there a setting for that too?
Merry Christmas! You are correct, lowest specific fuel consumption on the UL520iS is around 2400rpm. This could be preprogrammed into the controller for cruise or it could be reached through the hold function and manually adjusting the prop speed.
I want one on my UL520iS powered Cozy Mk. IV!
Can the prop controller be integrated with the engine ECU for true one-lever operation?
That would make a lot more sense than manually setting the speed.
Beautiful prop choice! Are there any issues with sandwiching the carbon fibre spinner backplate between the hub and 3/4” extension? I keep hearing about Galvanic corrosion but I’m also wondering how the composite will hold up under the compression (bearing) stress. Keep up the great work guys! It’s fabulous how you guys openly share so much of the design process with your viewers.
CF composite does not suffer oxidative corrosion, whether galvanic or otherwise.
@@IhabFahmy The composite does not corrode, but because it is conductive metals in contact with it may suffer galvanic corrosion. DarkAero has mentioned this many times in their videos, and did an entire video on it.
@@IhabFahmy ua-cam.com/video/yRpMZaU8zKw/v-deo.html
@@brianb-p6586 Thanks for the clarification. That's a good point. Actually, come to think of it, it's desirable for the fuselage to be conductive to minimize static charge accumulation and to reduce damage in case of a direct lightning strike. Galvanic corrosion of attached metal parts would be a side effect , unless these parts are electrically isolated from the carbon fuselage (could be as simple as a thin layer of electrically insulating between them). I'll find the videos you mentioned and watch them.
excited to see the end result.
AWESOME
Is there videos about the mounting of 2 parts using bolts? Like, where the propeller is mounted on the plane? What’s inside the part to make sure the propeller has a good grip and it’s firmly fixed on the frame?
I realize that mounting the pitch actuation motor on the rotating hub avoids a bearing, but the disk of exposed slip rings doesn't seem like a good tradeoff.
How am I going to protect the composite leading edges (Wing, rudder and cowling) from abrasion strikes and wear. Are there hardened surfaces or coatings to prevent cummulative surface damage?
Nicely engineered prop. Needs a inspection hole to set that third blade, don't fancy pulling that down if its not inline.
The installation of the last blade is a blind operation but you get to practice on the first two blades. :) It's not too difficult to "feel" the cam into the slider block. Just a little wiggling. This can be seen at 9:44 in the video. Thank you for watching!
Fascinating, gentlemen! One question- Would the propeller pitching mechanism default to a specific setting in case of electrical (and or mechanical)failure? Many thanks!
If the servo motor lost power the propeller would just remain at the pitch it is at, essentially reverting into a fixed pitch propeller. Same thing if there was some sort of mechanical failure in the motor, the blades remain where they are at since the blades can’t generate enough torque to backdrive the screw.
@@DarkAeroInc So if you had an engine failure, even if you still had electrical you would be unable to feather the prop to extend glide distance?
@@alexanderarnett4966 "in the motor", they meant the worm screw drive motor in the prob hub. If you have an engine failure, and still have battery power, you can control the blades.
@@alexanderarnett4966 I meant a mechanical failure in the electrical servo motor. If the engine died, the propeller could still be feathered.
@@MolsonB Exactly! You got to it before we did! Thank you!
What are the brushes used with the slip ring made of? How long do they last? Do the brushes require frequent inspection?
I've used a few slip rings in hobby robotics. It surprised me to see a slip ring on that propeller.
You early photo of the propeller made me wonder if it was variable pitch but I thought that would be way too complicated for a small airplane. It was really interesting to see I was wrong.
Thanks for the very interesting video.
A completely open brush and slip ring setup is even more surprising.
Good job! Darkaero1 is such an amazing and exciting project.
You've got a superb prop with a so nice simple control. I'm a little bit worried about your, also beautiful, big spinner: is it attached only by the back plate? In case, you can have inspiration with Mike Patey's one, wich is similar in size (i think) on his Scrappy.
Thank you for watching Laurent! There will also be a forward bulkhead within the spinner to help stabilize it.
Scappy is the better part of 200mph slower. That might make these two projects a little less comparable.
@@randallsemrau7845 i agree, but talking about a spinner is to consider rpm mainly. At take off and initial climb, Darkaero1 running at 3300 rpm is pretty much!
Was the propeller custom designed for you or is this an off the shelf design for them?
Timmy G, it's a little of both. The big items like the blades and hub are off the shelf but we did some more customized things with the spacers to get it to the right distance on the prop extension to match up with our spinner. It's faster and more cost effective to start with off the shelf parts and see how the performance turns out. We might explore some more customized adjustments with the blades after we see how it performs. Thank you for watching and for the question!
Modern props are works of art and this Airmaster is no different. I'd be hooking it up to a 12 V source and play around with making the blades change pitch. Merry (variable pitch) Christmas!
It would be tempting to play, but without installing it on a running engine the speed will be zero, so if it does anything it will just run to the fine pitch limit and sit there.
How do the wt, initial cost, annual inspection, TBO and overhaul costs compare on this to a conventional hydraulic prop?
I have a ground adj on my CT2K (2.5kg) and have excellent performances.
Awesome with predetermined settings! But shouldnt the feather swith be guarded? So you don't accidentally put it in feather
Just from looking at the controller panel, it appears the switch next to the Feather position provides the guard function. If so, it has to be in the Feather Enable position; otherwise "Feather" is the same as the preceding position on the switch. The indicator LED should tell the story; e.g., lit yellow for enabled but not feathered, and lit red for feathered.
G, day to Darkarrow,
I have only just subscribed to your channel. So, I will ketchup....
* I am a student pilot (CASA) and studying FAA regs.
* that was a very good prop assembly explanation.
* work safe and effective
Thanks for sharing the education.
🇭🇲🌏
That prop system looks really cool. One question I have though is regarding a fail safe for rpm control. Does that electrical control system have a way, if something were to fail, to bring that prop back to a high rpm setting similar to old hydraulic designs?
No, if the system fails it stays at whatever pitch it is at.
Does that propeller controller feed back to the throttle to keep from inadvertently oversquaring the engine when going down in RPM selections?
Does the propeller not have a negative pitch option for thrust reversal on landings?
Great video. Thanks. Those slip rings and brushes seem like a maintenance headache waiting to happen though. And the rest of your instrumentation is so much more beautiful than that archaic-looking prop control panel... can you just design an in-house alternative instead?
Just for style? That would be crazy.
@@brianb-p6586 Beautiful avionocs are far from crazy. The fuselage itself is designed for aerodynamics and style
@@IhabFahmy Brewing a custom version of a proven design of a critical system just so the knob on the panel looks better would absolutely be crazy. I wouldn't consider getting in an aircraft designed by someone who would do this.
DarkAero did not take an existing and proven fuselage design and entirely redesign it just for appearance.
@@brianb-p6586 You totally missed the point... I was asking that they redesign the knob, not the trim system 🤣. As to what aircraft you get into, well that's up to you.
@@IhabFahmy what you said was "control panel", not knob. Sure, if you want to change switch knob on the sane control panel to something less functional that you think is prettier, go for it.
Boy, am I ready for you to get into flight testing too. Any progress in the recent two years?
I hope you plan to polish the stainless steal leading edge! There are ways to do it without harming the carbon fiber resin clear coat finish, but simply using aluminum tape to mask it off, cut the aluminum tape after applying it with a fine exacto knife along the edge of the stainless steal, and then begin using an abrasive polish. This will increase aerodynamic effects and efficiency of the blade while in rotation. However this will be need to be done several times throughout its life span due to weathering and tiny bits of sand sized rocks. Having a polished leading edge looks great, and shows your attention to detail.
"sand sized rocks"
They wouldn't be called rocks if they were sand sized. Most people just call it sand and dirt.
Most airfoils don't see increased efficiency with ultra smooth surfaces, it's only the specialized laminar flow airfoils that make use of it and even then it's not necessary to have optical smoothness, just consistently accurate surfaces. You can only do so much with an airfoil surface before the boundary layer makes it irrelevant. In fact, the process of polishing the erosion strip would likely introduce enough inconsistencies to the shape of the leading edge that you'd end up worse off than when you started. Polishing out a tiny crater in the leading edge would mean having to take that much depth of material off the surrounding area by an inch or more, so now that inch of leading edge is shaped differently from the rest, which will change its aerodynamic characteristics. It's a losing proposition that won't gain you anything in the first place.
If you’re optimizing your wing for high speed flight, doesn’t a higher aspect ratio hurt your performance? At high speed, the extra span directly contributes to increased form drag, which is the dominant component of drag out to the right of Vmd on your Velocity/Drag curve. Also, what is the tradeoff between increasing aspect ratio vs. using winglets?
Were the blades modified to accommodate your 16.5 inch spinner ( to minimize the size of blade cutouts for blade pitch changes )
These videos are getting better. The music/montage 👍 Check out Trent Palmer’s recent vid on his intro. I think his theory for that type of thing would work well for you guys.
Does the prop have a failure default position? Does it default to fine pitch?
Looooks pretty sweet!
This reminds me of my EFII system on my bush plane. ..fits in a common panel hole.. Can we get a Beta setting on this ? We need one more lockout notch on that rotary switch...
4 month wait time for the prop is insane.
A little long, but hopefully it has improved since when we ordered ours!
@@DarkAeroInc that's the current wait time as of today.
@@dimsler2 Oh wow, good to know!
Out of curiosity: does this system lead to a high chance of prop pitch failure and runaway? Has it been tested much? And will the rain short the brushes?
Did you estimate cruise speed at 75 % power and 8000'? great project!
That is correct! Thanks for checking out the video!
Hey guys, I’m a private pilot in high school trying to learn as much as I can about aircraft design. With all the force on the blades on the prop, wouldn’t there be an incredible amount of force on the offset cams and the sliding block, and ultimately the leadscrew? Is there something I’m missing?
Will the tips stay below supersonic at 3300 rpm? I always thought 3 blade props were less efficient than two blade. I assume you went with three blades to keep the diameter smaller and tip speeds slower. Nice video and really nice job on your project. Keep it up guys!
Good question! The blade tips do stay below supersonic at 3300 rpm. Maximum continuous rpm on the engine is 2800 rpm which is more realistic number to look at for propeller tip speed at maximum cruise conditions. At that rpm is a pretty good margin below sonic. Thanks for watching!
3300 rpm = 3300 * 2π radians per minute
= 20734 radians per minute
= 20734 / 60 radians per sec
= 345 radians per second
Let's say that each blade is 1m long:
Wing tip velocity is 345 * 1m = 345 m/sec. The speed of sound is 343 m/sec. However, looking at the power / Torque curve, it seems like it will run just below 3300 rpm. Or maybe the blade length is less than 1m.
Edit: I didn't see DarkAero's reply :/
@@DarkAeroInc Three blades are *way* better looking, too!
@@StudioRV8 they do look pretty cool! 😎
@@andreashadjiantonis2596 SOS becomes lower as altitude / air density decreases.
Awesome.
To what tolerance are the blades balanced?
This propeller has been around for a long time. I remember seeing it on a Europa back in the late nineties.
nice device!
Guys ❤ ur DARKAERO. Q when is the 1st flight. Thx
I am patiently waiting for my kit so that I can parting the skies
What material is hélices of the projects?
How do you balance the spinner cone or is that not an issue because it's so light weight
Paul, we will end up balancing the system as a whole with the spinner attached. There are tools like the DynaVibe that allow you to get everything dialed in.
I noticed the PROP BOLTS are NOT wired. Do you plan to change those later so you can wire all the bolts? Safety first?
The blades look so small in relation to the spinner. But I'll take function over fashion anytime!
My Bonanza had an electrically actuated variable pitch propeller.
I would love to know how much this prop kit costs. Will wildguess something between 12 and 15 grand.
I think you underestimate the actual cost of carbon fiber parts, the time it takes to make them, the molds, the scraps, etc. My guess would be at 50k but maybe i'm the one who's too high up
@@antoineleblanc2509 I don't know, I just guessed it, maybe your estimate is more in the ballpark than mine is.
@@antoineleblanc2509 $50k for just the prop?
@@brianb-p6586 with moving parts and high tolerance carbon fiber pieces? Idk
@@antoineleblanc2509 anything related to aviation is expensive, but if the prop is $50K then the aircraft will be a million (it has many time as much carbon fibre). A quick web search suggests that José's guess is probably reasonable.
Kind of surprising to see a molex Mini Fit Jr. connectors on a critical aviation part.
How much is this plane going to cost or what price are you guys going to target sell it for?
Hi Harry! We keep the latest information about the kit on our website: www.darkaero.com/aircraft