Hi DarkAero Team. Very awesome to see your Dreams Coming True. The plane looks sweet and the Quality is right on do it Right First. Can’t wait to see the First Clear the Prop start Up. Love how Strong the Landing Gear Looks. Well Be Save and stay True to Your Goals.
@@DarkAeroInc Be Safe as we know your Team Is. I love the Carbon fiber Look. Very thought of Be the First F5J Sailplane made in America? Yes DarkAero comes First.
I have to say recently i've been following this endevour closely, its great to see more leaps being taken with general aviation to bring lighter, faster more efficent aircraft to market. I admit that I have a thing for vintage aircraft and simple technologies however having watched a lot of your videos It's reminded me that it is a mix of new and old, where wood composits were once used on aircraft like the DH Comet and mosquito, carbon fibre and fibre glass now exist, where slide rules and paper were once used, cad software can now be used. In some ways new technologies are simpler then old, and in some ways old simpler then new. Having worked on and flown 5 types of vintage aircraft I can say that they can be ergonomically challenging in many respects. From trying to undo nuts with minimal clearance for tools, requiring the use of custom tooling or excetionally small hands and high patience. To dealing with preventantive maintenance such as preventing wood from taking on moisture, correcting fabric issues using fabric tapes and dopes. As well as working on exceptionally rare engines with guidance from experts. This also is with consideration to varying climates as I live in the UK where it can be 15c one day and within a couple of days go down to -5c in the mornings where radials will struggle to reach correct operating temperatures, something we have been dealing with as exhaust manifolds crack and parts are rare to come by. It makes me wonder how such challenges will be addressed with composite aircraft, such as condensation in the wings especially if they're wet wings, to making sure the cores of the sandwiches do not get logged. I wonder how much lighter a 30s aircraft would be if designed with new composites over existing wood, fabric and metal structures. I for one would certainly like to fly a dark aero some day.
Hi guys. Electrical engineer here. My RUclips overlords stumbled me onto this video. This time they picked it right. Your project looks awesome! Got to go back now and root out all the earlier videos. Can't wait to see what comes next.
You guys are doing such an amazing job on this aircraft! Its fascinating to watch all of your hard work, ingenuity & craftsmanship, in designing the sleekest aircraft ever! The finished product is going to be legendary!
One of the hardest thing to do as a manufacturing or engineering group is to determine when too much engineering is going into a product. That very concept was what made Burt Rutan a genius. It get even more difficult when money is not an object.
You may want to consider using a better wear combination material or a striker plate for that latch and pin. Al is prone to wear damage and doesn't hold up well for latch applications.
Hi guys.in an emergency situation, how does the landing gear fall forward under gravity if it also has to fight aerodynamic loads trying to keep the leg and wheel rearward? Genuinely interested, not trying to pick hole.
C clips on the pivot pins would make me nervous. They rely on tension and in certain applications have been known to pop off. But, given your otherwise thorough design and engineering I'm sure you've considered alternatives. Nice work.
Not to throw shade on the guy who built the ‘raptor’ prototype, but man are you guys doing a much better job of considering and solving potential design issues before they arise. This thing looks like it’ll be more production ready than any other prototype that’s ever made it off the ground. Keep it up 👍
For the final design of the fuel delivery system for EFI engine, have you considered using a header tank where the dual fuel pumps and pressure regulators are located in the header tank? This is auto technology where the pumps are kept cool, uses less amps, and eliminates a return line from the engine since the regulator is in the header tank. This would also eliminate vapor lock, wouldn’t it?
Hi team .Greeting from Switzerland…been in engines marketing all my life, Cat but not Cummins !!!! To me your Darkaero design is not only good for a speed and long haul private market but with the specific large wing full tank design, the concept is also well suited to fit one of those new small turboprop (cruise missile engine derivative.. light helicopters start using those extensively) to produce a brand new intensive basic two side by side seats army trainer. Range is less critical for training and turboprop engine lower weigh offsets a larger fuel flow but not that much higher with lower drag flying high. Mandatory is an outstanding workhorse like old PT6a but much smaller, around 250-280 hp continuous power. .the maintenance and downtime would be minimal…and planes using economical jet fuel…many Air forces around the world are using over 900 old aluminium SF260 for basic and semi advanced training and with age, they all became replaceable by such a modern cost effective composite airframe with a modern CAPS cirrus parachute system and no individual parachute requirement. It outperforms easely in performance and productivity an electric winged wagon…Below a 10 mio$ PC21 with a huge 1600hp turboprop. there are plenty of training hours to log with a modern performing side by side very economical twin seater and not many candidates are that well adapted for it..but maybe it takes to JV with an advanced trainer producer, turboprop specialist, Pilatus Embraer etc with an existing ww army market coverage to be in their portfolio.. Philgood
Please give calculations for selection of engine. A) ground handling power required to overcome weight. B)power required to accelerate for take off. C) power required to ensure design climbing. D) power required to cruise. E) power required to ensure optimum bite of propeller in all above.
I am not an engineer. Far from it. But I am concerned about the beautifully close tolerances in the parts that you are making, and the coefficient of expansion of aluminum. The airplane could experience actual temperatures of -20 to +130. Does your CAD design software automatically take this into consideration? Personally, I would like you to address this issue in your videos.
Your videos are always great and it is obvious that you care about producing high-quality footage. That being said, my guess is that your audience would still appreciate slightly lower quality videos if we were able to get them a little more frequently. Otherwise, awesome build and thanks again for sharing with the YT community. I'm looking forward to buying my kit from you in a few years...
Those locking pawls on the main gear look like they could be prone to cracking, especially the lower one. I would expect it to crack at the root and bend out of engagement. I recommend changing it to stainless along with a small wear pad on the strut also in stainless.
In general on YT I'm dubious of decisions like the one you bring up but, these guys are really doing their homework. That being said, I too hope they change the latch component to something more durable than aluminum... It would be such a minor weight cost for a huge improvement in longevity/durability.
@@FiferSkipper I'm sure the latch they designed is Technically fine. I'm sure it would hold up for hundreds of hours and gear cycles. I'm also Very sure I'd take the ~3lb weight penalty. They could make it out of forged 7075-t6 type 3 hard anodized, probably would cost 3 times as much as stainless. Even the 7075 would possibly need to get dye-pen tested at annual. I'm sure the gear is very light but that latch is a real good concentration of Any forces available.
The quality of design and workmanship is truly wonderful. Even the temporary fuel tank solution is a work of art. Just one thought though, and I appreciate 3D aerodynamic design on what is, whilst most beautiful, still an aeroplane aimed at the self-build market. Is there perhaps a more aerodynamic, efficient and aesthetically pleasing solution you could offer for the wing tips? That’s not a criticism, your design work is absolutely exquisite, but just a question that I’m sure you’ve already answered in your own minds. David
Mr. Patey built his plane like a tank. These boys are building the F1 car of the skies. It's gonna be a real performer, and it's going to do its job well, but it will be very unforgiving and in a crash that landing gear is going through the occupants Vlad the Impaler style.
Was hoping you could do a video on your dual fuel pump set up. I've heard of a couple planes going down due to dual pump set ups and apparently it's possible for the pump to start pulling from the other pump instead the fuel tank. Also seen this issue in a car with dual pumps. The car issue was resolved with one way check valves.
Hi, the fuel pumps are currently set up with an on-on toggle switch to only run one at a time to avoid any potential feedback issues between the pumps.
I'm sure you guys have run the calculations and simulations, but it's hard to picture such a small latch handling the forces involved on the gear. I guess that's a testament to the engineering prowess of your team.
The drag link is the structure that constrains the gear strut, not the latch. The forces that are trying to pivot the gear struts pass through the drag links so it is the drag links that are doing all the work. The latches only hold the drag links in the correct orientation so the forces on the latches are much smaller than the forces on the drag links.
If the main gear can be deployed by pulling a lever in the cockpit and falling by gravity, what does the electric actuator accomplish? [Edit: okay, I figured it out. Electric retract.] I love the noises the machined parts make when they go together. You can hear the machining marks on the pivot pin as they slide into the trunnion.
Hi guys, fantastic progress and attention to detail, however, I have a question. You demonstrated the half gear for the landing strut, will there be TWO half gears per strut, ie one on each side of that securing "pin" rod that holds the gear??? I don't think one per landing gear strut is sufficient due to the torque factor on only one side of each strut. Many thanks for bringing us along on this epic engineering journey. Regards from South Africa
@@larrysorenson4789 recognizing sarcasm is apparently not your strength. What was your point in telling them "to wrap this up" and noting how long the effort has taken?
How? It will only prevent you from switching the bolt, or nut around, not the ring-terminals themselves. There is however a tried and working solution to this, different size stud and terminal for positive and negative ;)
3:10 would the gear fall far enough to hook onto the latch? it looks to me, as if the "down" isnt completely straight, but slightly towards the front, that in addition to airdrag that the gear receives, i can see it not reaching the latch if you just let it drop with gravity, if the electronics fail
There is also drag from the motor, so they have to ensure the gearbox is easily backdrivable or else the gear won't be able to move at all without power.
Great work on the plane! I appreciate you announcing the secret project at the end as the new shop, and I understand how announcing a secret project at the beginning of the video encourages viewing the whole video, but I wanted to share with you that it fell flat for me: My knee-jerk reaction was "oh these guys are like me and keep getting distracted by new projects, never finishing the old ones." I'm glad that it isn't the case and you three are better than me. I assume that most of your audience, like me, has some sense of the huge amount of work between now and flying: I would be weary of making announcements that sound like you're changing focus from that goal. The best of luck to you guys: I look forward to seeing your mountains of effort pay off!
John, good question. The doors for the main gear are still something we are finalizing. We are planning on doing two to three doors for each main gear - one for the wheel area and one to two for the strut area.
I am just curious if the gear will lock into the down position if you have to gravity deploy it in emergency, as you told. Lot of drag from the airflow for a forward pivoting gear leg. I love your build quality guys!
You are correct that the gear are fighting aerodynamic forces as they extend since they swing forward. Each gear strut has a gas spring connected to it to provide the extra extend force required to overcome aerodynamic loads and reach the down locked position. Gravity does the initial work pulling the gear down and the gas spring takes it the rest of the way. This was omitted from the discussion in the video, so we are glad you asked about it and gave us the chance to elaborate on the design!
What software did you use to conduct your FEA of the gear lock latches? I am doing my doctorate in polymer based additive FEA and am always curious as to others approaches.
Hi. Good progress so far and congratulations on the new shop. When building the plane how do you document your progress ? Since with all the back and forth involved in releasing a prototype how do you establish a streamlined process.
Hi mr-matt! We rely heavily on physical testing to validate the composite structures we build. We also use simulation tools for certain structures and for predicting aerodynamic characteristics. Here are a few videos highlighting some of the more interesting validation work we've performed: Stall Simulation - ruclips.net/video/gjNPEDBeiTI/видео.html Wing Proof Load Testing - ruclips.net/video/7hvu-oQZdvE/видео.html Firewall Testing - ruclips.net/video/R25bl-EgW1k/видео.html Nose Gear Testing - ruclips.net/video/nRuLWA9iEGE/видео.html
When I heard secret project while you were talking about engine stuff I was thinking 520T especially with a 20K ceiling :) Obviously a weight penalty but be curious what the tradeoffs would spec out to. Hits 200HP at 20K alt which is kind of crazy. Could definitely run it down much lower throttle up there I'd think.
As usual I am in awe of your build quality (and the quality of your videos!) but looking at your work reminds me of the Icon A5. It is also a superbly engineered and built aircraft, but this in turn resulted in very high build costs due to the complexity of the design, so now it is priced so high that no one can afford to buy it. A fixed gear variant with very a sophisticated aerodynamic design may be worth considering in the future- less weight, less risk, more room in fuse, more load carrying ability, less maintenance, lower cost.
As a certified technician, with the "what if..." hat on; In case of MLG actuator(motor) failure, and manual down-release (which you have covered, which is good) is needed , how are you going to ensure down-lock when the leg has to move against air-drag, instead of being extended by air-drag? I'm also a bit worried about the loads on the what-would-have-been a drag strut/brace, which in this case seems to be under compressive load during breaking instead of under tension (which is more stable) especially considering the lock being so close to the center of rotation, which will put it under great force if the brace was to come even slightly out of center during compressive load.
There is a gas spring connected to each gear strut to push it down against aerodynamic loads and into the down locked position. This wasn't discussed in the video, but it's basically the same arrangement on the nose gear which we have shown in earlier videos. The drag links can experience either tension or compression depending on the specific landing or braking conditions you are analyzing. The drag link carries essentially all the load to stabilize the strut while the lock pin is very lightly loaded since it just constrains the upper drag link in a straight line with the load during braking or initial wheel spin up on touchdown. Thanks for checking out the video and for the extra set of eyes on the design! :)
The resistance from the retract motor was a hurdle we had to overcome when we were designing in the emergency extend functionality. The mechanical disengage of the lock latch is tied into the retract motor to decouple the motor from the strut assembly so the resistance of back driving the retract motor doesn't prevent the strut from making it to the down locked position. We have the same architecture in the nose gear system.
@@DarkAeroInc Awesome. You are definitely putting some weight budget into the landing gear systems. Landing gear handling is sometimes one of the greater unknowns - be interesting to see model matches tested behavior (less concerned about raise / drop, more just feeling on landing / takeoff / taxi etc.)
I'm not at all into airplanes but this project has me all propped up. There's so much interesting stuff that goes into it that makes me want to know every detail, from materials to fabrication and design choices. Also, this is the first time I saw the finished paint scheme and it made me wish for an all carbon fiber version of it. Are there regulations requiring the wings to be painted? Just curious to know! Looking forward to the next update!
Hi Dirceu! We are happy to hear that you are enjoying the information we are sharing about our aircraft! There aren't regulations that dictate our paint color, it's governed by the limits of the materials we selected. Dark colors like black or raw carbon can heat up in the sun and potentially soften the epoxy resin that holds the carbon fiber in its specific shape. We selected high temperature epoxy to enable the structure to tolerate this type of heating, but we want to complete more thorough validation work to firmly establish the upper temperature limits of the structure. In the meantime, we are going to use light colors on primary flight structures of the prototype like the wings and tail and UV resistant clear coat on non structural areas like the cowling and spinner to still show off the carbon fiber aesthetic.
Normally you need to reduce speed to a certain point - for example in a Cessna you might lower gear only at 125 or less, but if you need to do an emergency extend they often want your lower (ie, < 90 kts). So that reduces drag a fair bit. Then these guys have a gas strut that pushes things. Finally, a gear up landing is not necessarily game over. I sometimes wish planes would ship with three skid plates so you could skid on the runway with something that was replaceable and kept the prop off the tarmac but I've never seen that except for on RC planes.
The pilot can't see the gear. There should be a position sensor and a lock sensor and a small 4 inch display in the cockpit showing the gear position and lock status with page 2 showing a camera view of the gear. In bad weather or if the gear hardware gets bent the pilot can move to make a decision for a gear up landing.
I live in Tampa by salt water so the carbon fiber appeals to me. On the aluminum parts, is there something that you will be doing to coat or prevent corrosion on the metal parts?
The UL520iS engine we are using is FADEC controlled so there is no mixture lever. Technically it isn't a true FADEC as we have it implemented because the propeller control is independent. There isn't a propeller lever, but rather a knob control which is used to select different flight modes like takeoff, climb, and cruise. We made a detailed video about the propeller here: ruclips.net/video/riOTy9m0WTY/видео.html Thanks for watching and for the question!
I just stumbled across this project and am very impressed that these young guys are tackling such a large project. I tried to build an RV6 and failed and I didn't have to design and engineer it. Not sure I would be a future customer, but would love to see the finished product. Are you based at the Madison or Middleton airport?
We all greatly appreciate this exciting update. We’ve missed you pretty bad.
This transperancy in the build process is soo unique and the future of manufacturing. You people are soo ahead of the curve.
The click when the gear locks, and how solid the whole unit is when that happens is very satisfying.
Great to see young Engineers working hard and doing so well. Very Well done guys!
I knew it was a good morning when I saw the DarkAero notification. Love spending time with your channel.
Hi DarkAero Team. Very awesome to see your Dreams Coming True. The plane looks sweet and the Quality is right on do it Right First. Can’t wait to see the First Clear the Prop start Up. Love how Strong the Landing Gear Looks. Well Be Save and stay True to Your Goals.
Thank you! We are really excited for the first engine start and first flight as well!
@@DarkAeroInc Be Safe as we know your Team Is. I love the Carbon fiber Look. Very thought of Be the First F5J Sailplane made in America? Yes DarkAero comes First.
I have to say recently i've been following this endevour closely, its great to see more leaps being taken with general aviation to bring lighter, faster more efficent aircraft to market. I admit that I have a thing for vintage aircraft and simple technologies however having watched a lot of your videos It's reminded me that it is a mix of new and old, where wood composits were once used on aircraft like the DH Comet and mosquito, carbon fibre and fibre glass now exist, where slide rules and paper were once used, cad software can now be used. In some ways new technologies are simpler then old, and in some ways old simpler then new.
Having worked on and flown 5 types of vintage aircraft I can say that they can be ergonomically challenging in many respects. From trying to undo nuts with minimal clearance for tools, requiring the use of custom tooling or excetionally small hands and high patience. To dealing with preventantive maintenance such as preventing wood from taking on moisture, correcting fabric issues using fabric tapes and dopes. As well as working on exceptionally rare engines with guidance from experts. This also is with consideration to varying climates as I live in the UK where it can be 15c one day and within a couple of days go down to -5c in the mornings where radials will struggle to reach correct operating temperatures, something we have been dealing with as exhaust manifolds crack and parts are rare to come by.
It makes me wonder how such challenges will be addressed with composite aircraft, such as condensation in the wings especially if they're wet wings, to making sure the cores of the sandwiches do not get logged. I wonder how much lighter a 30s aircraft would be if designed with new composites over existing wood, fabric and metal structures. I for one would certainly like to fly a dark aero some day.
Hi guys. Electrical engineer here. My RUclips overlords stumbled me onto this video. This time they picked it right. Your project looks awesome! Got to go back now and root out all the earlier videos. Can't wait to see what comes next.
Those gear lock clicking noises are sooooo satisfying 🙂
You guys are doing such an amazing job on this aircraft! Its fascinating to watch all of your hard work, ingenuity & craftsmanship, in designing the sleekest aircraft ever! The finished product is going to be legendary!
Such a satisfying sound when it locks, really nicely designed!
Love the video. One thing that makes it so interesting is that all of you are good teachers!
Incredible project guys! You do a great job with your videos, can’t wait for first engine start!
Great to see you back. Exciting times. Can’t wait to see her fired up. 🇨🇦
Big compliments for your process, with the big concept lines and the small details. Nice to follow this. Good luck with the last steps.
I check up on you guys once in a while. Pro from start to finish. Keep rocking it guys, very well done.
Nice job on the firewall pass-through and the ingenious up/down locks! Keep at it, we all expect to see and oogle over it at OSH this year!
Can't wait for you guys to fly your plane. Keep us posted, your videos are fascinating.
Hire a professional test pilot for that.
Great design and workmanship! Thank you for bringing us all along. Excited to see the final product.
Fabulous! Hope to see her flying soon!
Hey thanks for showing us your work and explaining processes and designs.
One of the hardest thing to do as a manufacturing or engineering group is to determine when too much engineering is going into a product. That very concept was what made Burt Rutan a genius. It get even more difficult when money is not an object.
Awesome progress! Can't wait to see her spinnin' on her own 😀
Beautiful machining, they even sound good when fitting together.
Keep up the great work fellas. I can’t wait to see her fly.
Can't wait to see her fly.
Such a beautiful design.
You may want to consider using a better wear combination material or a striker plate for that latch and pin. Al is prone to wear damage and doesn't hold up well for latch applications.
The sound of that latch is heaven
Exciting stuff! Cant wait to see more :)
Finally I love following up on this project. Keep it up.👍🏻
Hi guys.in an emergency situation, how does the landing gear fall forward under gravity if it also has to fight aerodynamic loads trying to keep the leg and wheel rearward? Genuinely interested, not trying to pick hole.
Jinking the nose down abruptly and hope the maneuver and wheel weight will overcome wind resistance.
Great progress update! I can't wait to see the engine start up.
Good professional processes, step by step, to create a production ready airplane. This project deserves to become a series production aircraft.
It's been a minute since you guys posted a video. I figured you guys were working hard.
C clips on the pivot pins would make me nervous. They rely on tension and in certain applications have been known to pop off. But, given your otherwise thorough design and engineering I'm sure you've considered alternatives. Nice work.
80% done, 80% to go! Pretty stoked for first start guys. Can't wait!
Funny joke, I'm stealing it, LOL!
Not to throw shade on the guy who built the ‘raptor’ prototype, but man are you guys doing a much better job of considering and solving potential design issues before they arise. This thing looks like it’ll be more production ready than any other prototype that’s ever made it off the ground. Keep it up 👍
For the final design of the fuel delivery system for EFI engine, have you considered using a header tank where the dual fuel pumps and pressure regulators are located in the header tank? This is auto technology where the pumps are kept cool, uses less amps, and eliminates a return line from the engine since the regulator is in the header tank. This would also eliminate vapor lock, wouldn’t it?
Doing very well, looking fwd for the first engine run and high speed taxi.
I know nothing about what you guys are doing but it looks very impressive.
Hi team .Greeting from Switzerland…been in engines marketing all my life, Cat but not Cummins !!!! To me your Darkaero design is not only good for a speed and long haul private market but with the specific large wing full tank design, the concept is also well suited to fit one of those new small turboprop (cruise missile engine derivative.. light helicopters start using those extensively) to produce a brand new intensive basic two side by side seats army trainer. Range is less critical for training and turboprop engine lower weigh offsets a larger fuel flow but not that much higher with lower drag flying high. Mandatory is an outstanding workhorse like old PT6a but much smaller, around 250-280 hp continuous power. .the maintenance and downtime would be minimal…and planes using economical jet fuel…many Air forces around the world are using over 900 old aluminium SF260 for basic and semi advanced training and with age, they all became replaceable by such a modern cost effective composite airframe with a modern CAPS cirrus parachute system and no individual parachute requirement. It outperforms easely in performance and productivity an electric winged wagon…Below a 10 mio$ PC21 with a huge 1600hp turboprop. there are plenty of training hours to log with a modern performing side by side very economical twin seater and not many candidates are that well adapted for it..but maybe it takes to JV with an advanced trainer producer, turboprop specialist, Pilatus Embraer etc with an existing ww army market coverage to be in their portfolio.. Philgood
Please give calculations for selection of engine.
A) ground handling power required to overcome weight.
B)power required to accelerate for take off.
C) power required to ensure design climbing.
D) power required to cruise.
E) power required to ensure optimum bite of propeller in all above.
I am not an engineer. Far from it. But I am concerned about the beautifully close tolerances in the parts that you are making, and the coefficient of expansion of aluminum. The airplane could experience actual temperatures of -20 to +130. Does your CAD design software automatically take this into consideration? Personally, I would like you to address this issue in your videos.
Your videos are always great and it is obvious that you care about producing high-quality footage.
That being said, my guess is that your audience would still appreciate slightly lower quality videos if we were able to get them a little more frequently.
Otherwise, awesome build and thanks again for sharing with the YT community. I'm looking forward to buying my kit from you in a few years...
Those locking pawls on the main gear look like they could be prone to cracking, especially the lower one. I would expect it to crack at the root and bend out of engagement. I recommend changing it to stainless along with a small wear pad on the strut also in stainless.
Lock dog galling, creep, hardened tool steel sear at pall. Good stuff Sven offered a two step self tightening and self cleaning angles.
In general on YT I'm dubious of decisions like the one you bring up but, these guys are really doing their homework. That being said, I too hope they change the latch component to something more durable than aluminum... It would be such a minor weight cost for a huge improvement in longevity/durability.
@@FiferSkipper I'm sure the latch they designed is Technically fine. I'm sure it would hold up for hundreds of hours and gear cycles. I'm also Very sure I'd take the ~3lb weight penalty. They could make it out of forged 7075-t6 type 3 hard anodized, probably would cost 3 times as much as stainless. Even the 7075 would possibly need to get dye-pen tested at annual. I'm sure the gear is very light but that latch is a real good concentration of Any forces available.
The video shows that the latch engages a pin (presumably steel) on the gear, not the aluminum gear component directly.
The quality of design and workmanship is truly wonderful. Even the temporary fuel tank solution is a work of art. Just one thought though, and I appreciate 3D aerodynamic design on what is, whilst most beautiful, still an aeroplane aimed at the self-build market. Is there perhaps a more aerodynamic, efficient and aesthetically pleasing solution you could offer for the wing tips? That’s not a criticism, your design work is absolutely exquisite, but just a question that I’m sure you’ve already answered in your own minds. David
Awesome! Stay the course guys!
I can’t wait to see her first flight. Well Done Gentlemen
Interesting point about the effect of engine thrust/hard braking on the rearward folding gear. Your down-latch is a bit more "critical" than usual.
This is extremely cool!
Great video. I'm interested in how you interfaced carbon and aluminium. Is there any special coating between those two?
They did an excellent video on this exact subject. Search their channel for it and enjoy. Welcome to the DarkAero YT community.
@@FiferSkipper Thanks! Just saw that video. Amazing explanation of the problem. The fiberglass layer makes the most sense for my application.
Getting close to that big day. You have potentially the best engineered airplane of all time, even rivaling Mike Patey
Mr. Patey built his plane like a tank. These boys are building the F1 car of the skies. It's gonna be a real performer, and it's going to do its job well, but it will be very unforgiving and in a crash that landing gear is going through the occupants Vlad the Impaler style.
that latch catch was neat
Was hoping you could do a video on your dual fuel pump set up. I've heard of a couple planes going down due to dual pump set ups and apparently it's possible for the pump to start pulling from the other pump instead the fuel tank. Also seen this issue in a car with dual pumps. The car issue was resolved with one way check valves.
Hi, the fuel pumps are currently set up with an on-on toggle switch to only run one at a time to avoid any potential feedback issues between the pumps.
I'm sure you guys have run the calculations and simulations, but it's hard to picture such a small latch handling the forces involved on the gear. I guess that's a testament to the engineering prowess of your team.
The drag link is the structure that constrains the gear strut, not the latch. The forces that are trying to pivot the gear struts pass through the drag links so it is the drag links that are doing all the work. The latches only hold the drag links in the correct orientation so the forces on the latches are much smaller than the forces on the drag links.
Incredible looking aircraft and components 🤙
i wish you the best, great progress
If the main gear can be deployed by pulling a lever in the cockpit and falling by gravity, what does the electric actuator accomplish?
[Edit: okay, I figured it out. Electric retract.]
I love the noises the machined parts make when they go together. You can hear the machining marks on the pivot pin as they slide into the trunnion.
Is there any lift component to the horizontal stabilizer? It looks to be flat,
Horizontal stabilizers normally provide a down force (negative lift) in steady-state flight.
First you have to sit on it and then spin the blades right?
Electric (rather than hydraulic) brake actuation may be easier to route, and possibly lighter weight?
This is amazing!
will the gear be able to unlock from the down position with weight on the assembly, or will it have to be either airborne or on jacks to unlock?
Hi guys, fantastic progress and attention to detail, however, I have a question. You demonstrated the half gear for the landing strut, will there be TWO half gears per strut, ie one on each side of that securing "pin" rod that holds the gear??? I don't think one per landing gear strut is sufficient due to the torque factor on only one side of each strut.
Many thanks for bringing us along on this epic engineering journey.
Regards from South Africa
Are you using steel bushings in the drag links at the pivot point were the bolt goes through?
You guys really need to wrap this up. It seems like years ago when you started. Still a fantastic engineering and fabrication story.
Who do you think these guys are, @MikePatey?
@@aggiewoodie engineering and fabrication visionary geniuses, of course. What is your point?
Gee, I'm sure it never occurred to them that it is taking a long time.
@@brianb-p6586 your point?
@@larrysorenson4789 recognizing sarcasm is apparently not your strength. What was your point in telling them "to wrap this up" and noting how long the effort has taken?
So are braking forces going through that latch?
Braking forces go through the drag links. The latch only stabilizes the drag links to keep them from folding.
@@DarkAeroInc Makes sense. This is a very exciting aircraft! Long range, high speed is what I want.
Impressed!
Regarding engine electric connections plate: Consider making one of the battery lugs left hand thread. This will prevent reverse polarity connection.
How? It will only prevent you from switching the bolt, or nut around, not the ring-terminals themselves.
There is however a tried and working solution to this, different size stud and terminal for positive and negative ;)
In case Red and Black (or green) don’t work?
@@tomcoryell hehe
3:10 would the gear fall far enough to hook onto the latch? it looks to me, as if the "down" isnt completely straight, but slightly towards the front, that in addition to airdrag that the gear receives, i can see it not reaching the latch if you just let it drop with gravity, if the electronics fail
There is a gas strut to assist the forward motion.
There is also drag from the motor, so they have to ensure the gearbox is easily backdrivable or else the gear won't be able to move at all without power.
I just made this same comment. Im no engineer but seems a tough ask to get it to fight drag using gravity alone
Great work on the plane!
I appreciate you announcing the secret project at the end as the new shop, and I understand how announcing a secret project at the beginning of the video encourages viewing the whole video, but I wanted to share with you that it fell flat for me: My knee-jerk reaction was "oh these guys are like me and keep getting distracted by new projects, never finishing the old ones." I'm glad that it isn't the case and you three are better than me.
I assume that most of your audience, like me, has some sense of the huge amount of work between now and flying: I would be weary of making announcements that sound like you're changing focus from that goal.
The best of luck to you guys: I look forward to seeing your mountains of effort pay off!
There will be alot of torque transmitted through those gear teeth. I'm sure it's all calculated and simulated
When is this aircraft going to fly? What engineering and mechanical issues are preventing it from flight testing?
With that lock on the gear for g load, what sort of spin and roll characteristics will the aircraft have? What sort of g limit would it be looking at?
What will the landing gear testing program look like for your dream machine?
Curious what the main gear doors will look like and how they’ll function. Haven’t seen any coverage on the design.
John, good question. The doors for the main gear are still something we are finalizing. We are planning on doing two to three doors for each main gear - one for the wheel area and one to two for the strut area.
I'm curious - how many unique parts (non off the shelf ) are in the plane?
I hope that latch thing is made of titanium, cause it's really gonna have a lot stress applied to it
I am just curious if the gear will lock into the down position if you have to gravity deploy it in emergency, as you told. Lot of drag from the airflow for a forward pivoting gear leg.
I love your build quality guys!
You are correct that the gear are fighting aerodynamic forces as they extend since they swing forward. Each gear strut has a gas spring connected to it to provide the extra extend force required to overcome aerodynamic loads and reach the down locked position. Gravity does the initial work pulling the gear down and the gas spring takes it the rest of the way. This was omitted from the discussion in the video, so we are glad you asked about it and gave us the chance to elaborate on the design!
What software did you use to conduct your FEA of the gear lock latches? I am doing my doctorate in polymer based additive FEA and am always curious as to others approaches.
Hi. Good progress so far and congratulations on the new shop. When building the plane how do you document your progress ? Since with all the back and forth involved in releasing a prototype how do you establish a streamlined process.
I noticed there are tennis balls on all the wingtips, may I ask what corner you crunched that taught you?
Corner of my skull.
I have had a similar problem in the past 😂
Love y’all’s stuff looking forward to seeing it fly!!
What sort of testing and validation do you do? Simulations? Physical testing etc?
Hi mr-matt! We rely heavily on physical testing to validate the composite structures we build. We also use simulation tools for certain structures and for predicting aerodynamic characteristics. Here are a few videos highlighting some of the more interesting validation work we've performed:
Stall Simulation - ruclips.net/video/gjNPEDBeiTI/видео.html
Wing Proof Load Testing - ruclips.net/video/7hvu-oQZdvE/видео.html
Firewall Testing - ruclips.net/video/R25bl-EgW1k/видео.html
Nose Gear Testing - ruclips.net/video/nRuLWA9iEGE/видео.html
When I heard secret project while you were talking about engine stuff I was thinking 520T especially with a 20K ceiling :) Obviously a weight penalty but be curious what the tradeoffs would spec out to. Hits 200HP at 20K alt which is kind of crazy. Could definitely run it down much lower throttle up there I'd think.
I reckon they could do super high ceiling, pressurized cabin, in pusher configuration with canard.. And maybe a diesel for efficiency
@@nathanchalecki4842 sure... and that would be an entirely different aircraft, not sharing a single component.
Man thats a neat aramid design!!!! You get close to 500mph yiuve suceeded
As usual I am in awe of your build quality (and the quality of your videos!) but looking at your work reminds me of the Icon A5. It is also a superbly engineered and built aircraft, but this in turn resulted in very high build costs due to the complexity of the design, so now it is priced so high that no one can afford to buy it. A fixed gear variant with very a sophisticated aerodynamic design may be worth considering in the future- less weight, less risk, more room in fuse, more load carrying ability, less maintenance, lower cost.
As a certified technician, with the "what if..." hat on;
In case of MLG actuator(motor) failure, and manual down-release (which you have covered, which is good) is needed , how are you going to ensure down-lock when the leg has to move against air-drag, instead of being extended by air-drag?
I'm also a bit worried about the loads on the what-would-have-been a drag strut/brace, which in this case seems to be under compressive load during breaking instead of under tension (which is more stable) especially considering the lock being so close to the center of rotation, which will put it under great force if the brace was to come even slightly out of center during compressive load.
Also, there will be resistance from the motor.
There is a gas spring connected to each gear strut to push it down against aerodynamic loads and into the down locked position. This wasn't discussed in the video, but it's basically the same arrangement on the nose gear which we have shown in earlier videos. The drag links can experience either tension or compression depending on the specific landing or braking conditions you are analyzing. The drag link carries essentially all the load to stabilize the strut while the lock pin is very lightly loaded since it just constrains the upper drag link in a straight line with the load during braking or initial wheel spin up on touchdown. Thanks for checking out the video and for the extra set of eyes on the design! :)
The resistance from the retract motor was a hurdle we had to overcome when we were designing in the emergency extend functionality. The mechanical disengage of the lock latch is tied into the retract motor to decouple the motor from the strut assembly so the resistance of back driving the retract motor doesn't prevent the strut from making it to the down locked position. We have the same architecture in the nose gear system.
@@DarkAeroInc Awesome. You are definitely putting some weight budget into the landing gear systems. Landing gear handling is sometimes one of the greater unknowns - be interesting to see model matches tested behavior (less concerned about raise / drop, more just feeling on landing / takeoff / taxi etc.)
You might have mentioned it already, but do you have two ECUs for redundancy? Or am I missing the purpose of having those two ecu bulkhead fittings?
Yes, we have two ECUs in the prototype aircraft for redundancy. The engine can be configured with either one or two ECUs.
@@DarkAeroInc I don't know about everyone else, but I'd love to understand more about redundancy in systems for aerospace.
Good job!
What a cool project!!!!
I'm not at all into airplanes but this project has me all propped up. There's so much interesting stuff that goes into it that makes me want to know every detail, from materials to fabrication and design choices. Also, this is the first time I saw the finished paint scheme and it made me wish for an all carbon fiber version of it. Are there regulations requiring the wings to be painted? Just curious to know! Looking forward to the next update!
Hi Dirceu! We are happy to hear that you are enjoying the information we are sharing about our aircraft! There aren't regulations that dictate our paint color, it's governed by the limits of the materials we selected. Dark colors like black or raw carbon can heat up in the sun and potentially soften the epoxy resin that holds the carbon fiber in its specific shape. We selected high temperature epoxy to enable the structure to tolerate this type of heating, but we want to complete more thorough validation work to firmly establish the upper temperature limits of the structure. In the meantime, we are going to use light colors on primary flight structures of the prototype like the wings and tail and UV resistant clear coat on non structural areas like the cowling and spinner to still show off the carbon fiber aesthetic.
@@DarkAeroInc I haven't thought of that. Thanks for the reply!!
Question! In the event of having to lower the gear manually, how is the drag of airflow overcome to get the gear locked down?
Great question! There is a gas spring connected to each strut that pushes the strut down against aerodynamic loads and into the down locked position.
Normally you need to reduce speed to a certain point - for example in a Cessna you might lower gear only at 125 or less, but if you need to do an emergency extend they often want your lower (ie, < 90 kts). So that reduces drag a fair bit. Then these guys have a gas strut that pushes things. Finally, a gear up landing is not necessarily game over. I sometimes wish planes would ship with three skid plates so you could skid on the runway with something that was replaceable and kept the prop off the tarmac but I've never seen that except for on RC planes.
The pilot can't see the gear. There should be a position sensor and a lock sensor and a small 4 inch display in the cockpit showing the gear position and lock status with page 2 showing a camera view of the gear. In bad weather or if the gear hardware gets bent the pilot can move to make a decision for a gear up landing.
I live in Tampa by salt water so the carbon fiber appeals to me. On the aluminum parts, is there something that you will be doing to coat or prevent corrosion on the metal parts?
Hi David! The aluminum parts will have corrosion protection, either anodization or paint depending on the specific component.
Do you plan to use a FADEC of any type for the prop and mixture control? Or a traditional 3 lever system
The UL520iS engine we are using is FADEC controlled so there is no mixture lever. Technically it isn't a true FADEC as we have it implemented because the propeller control is independent. There isn't a propeller lever, but rather a knob control which is used to select different flight modes like takeoff, climb, and cruise. We made a detailed video about the propeller here: ruclips.net/video/riOTy9m0WTY/видео.html Thanks for watching and for the question!
Will it FLY in time for Oshkosh ?
One more question, since this is built for high speed XC flights, would it be modifiable easily to be a realistic Reno air racing competitor?
It's not structurally designed for aerobatic flight limits.
I just stumbled across this project and am very impressed that these young guys are tackling such a large project. I tried to build an RV6 and failed and I didn't have to design and engineer it. Not sure I would be a future customer, but would love to see the finished product. Are you based at the Madison or Middleton airport?
Thanks for checking out the project! We are located at Dane County Regional Airport in Madison, WI.
You should shear test the lock mechanism fasteners and lock mechanism. It's a failure point.
No header tank?