Engineering softer landings (drop testing)

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In this video we'll be drop testing the nose gear of the DarkAero 1 prototype. The goal is to simulate a bad landing in a safe and controlled manner so that we can verify that the nose gear will perform as expected before we proceed into flight testing.
Before we drop the nose gear to see how it performs, we'll take a closer look at the gear design, the test rig, and discuss the importance of this test.
0:00 - Intro
0:40 - DarkAero 1's Mission
1:56 - Nose Gear Engineering
4:46 - Why Drop Test The Gear?
6:20 - Test Setup
8:07 - Testing Results
10:00 - Outro
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[@billardman2]

As a consulting engineer of over 30 years , I am seeing new engineers start their careers and it worries me a little with their lack of professionalism and attention to detail. But then I watch your videos. As a pilot and lover of the engineering process, I can say that you guys have renewed my faith in the next generation of engineers. You are concise with your explanations without making it too difficult for the lay person to understand. Bravo!

[@ramenhausten]

Do you need a mechatronics engineer apprentice by any chance ?

[@chester8420]

What?! Their "test rig" is made from busted up shipping crates bolted to a beam in the shop and filled with sandbags.

[@JMC8415]

@@chester8420 I don't see what's wrong with that. They are testing the landing gear, not the test rig.

[@chester8420]

@@JMC8415 I was just implying that the test was silly. I can't imagine a situation where the nose gear of the aircraft would be rotating downward on a beam of wood with a flimsy box of sandbags sat on top. It made an interesting video, but an aircraft would never impact the runway in such a manner. Unless its fuselage were somehow bolted to the shop beam.

[@jakubjochec]

​@@JMC8415 ehm, at least read his full response first...

[@Macrocompassion]

The mass on the nose-gear that is needed for a simulated landing impact, is much greater that the equivalent static weight being carried when standing or taxiing on a smooth surface. This is because the pitching motion of the aircraft adds inertial mass to the static mass. My work (and engineering paper in the American Journal of Aircraft) shows that this dynamic effect can increase the size of the so-called static mass by up to 3 times, so we need to design the nose gear to withstand much more force during a landing impact than only that from its static weight reactive load. We need to include the effect of both sinking speed and equivalent mass due to pitching. When taxiing over bumpy surfaces there also is an equivalent mass on the nose-gear due to the pitching motion of the whole aircraft. To better understand this, a simulation of the complete mechanical parts is needed. This is what my paper was all about. Past experience on the Airbus A200, some years ago, showed that the formal method for calculating this equivalent mass as specified in the airworthiness regulations was insufficient, and that fatigue strength and life was limited due to this incorrect resulting fatigue spectrum being originally used. My paper about it is still relevant because I wrote it so as to cover a range of parameters suitable for application to many tricycle layout aircraft landing gears.

[@Gearlube_chain_wax_solutions]

Very professional. With every video I see, I am even more impressed with the way you guys handle this. Keep it up !!

[@Sep141]

Awesome progress. You guys are a credit to the state, look forward to every upload you do. Keep it up, greetings from the Fox Valley!

[@SteinAir]

VERY nice job guys - keep up the great work! It's extremely reassuring to see you doing actual testing (some people selling plans/kits have never drop tested their gear, or do minimal job of it). Nice to see both the theoretical engineering as well as the practical testing on all the various components and sub-components. Will make for a great plane when it's done. Keep up the good work, we can't wait to see it finished (but are glad to see you taking these steps in the meantime) - See ya at OSH!

[@cabanford]

Love the "into the last minute detail" engineering. Was always a dream of mine to design and build my own aircraft - like you guys are doing... Dream it shall remain, but lots of my dreaming is reality here with you. ❤

[@boydw1]

I'd anticipate that some of the worst possible nose gear loads would be in a nose down "wheelbarrow" contact. You could probably get closer to simulating that by raising the pivot point of your test rig. Probably also want to consider lateral loads that might be encountered in a bad crosswind landing.

[@TheRangerBob]

Once again, impressively well thought-out. Looking forward to some flight tests.

[@tomcoryell]

I am grateful to the Dark Aero team for all of the knowledge you giveaway.I’ve learned a lot.

[@williamwilliam728]

Baby steps are getting you closer to that first flight. I am very impressed with your engineering and decision to make it better than FAA regulations. Waiting in anticipation for that first flight. 😃

[@adamlowe005]

Very cool, very professional, great safety and efficiency focus … well done guys !!!

[@flyribbit]

Congratulations on 100k subscribers! 🎉 Keep up the great work DarkAero team.

[@rogerclarke3291]

Hi from the UK. The design of your landing gear is beautiful. Thanks for sharing.

[@lorendjones]

Very impressive design, top to bottom. Thanks for sharing your journey with us.

[@bradalgra8088]

Beautiful work, as always. Ground handling safety is so important and directional stability upon touchdown is critical in preventing landing accidents. Continued success with the Dark Aero!

[@Johnbobon]

Don't all airplane accidents occur on the landing? J/k

[@bartofilms]

More Excellent Engineering. I realize the drop rig is wood, not metal, but I could not help but notice the stress on what would be the interface between engine mount and fuselage. Have you considered drop tests for these components and the engine mount bolts? Cheers.

[@gregoryh4601]

Job well done you Three . I hope the FAA looks at your build more Closely and makes changes to there Rules. The front Shock be awesome for the RC Airplanes Hobby. It would help Us land better too! Well done.

[@edstube2668]

Nice work boys! Thanks for sharing another impressive video. Keegan raising the bar even higher…

[@rickfaber1958]

Nice job thinking out the homemade, yet seemingly effective, test rig. However, I'm wondering if you're planning to conduct non-destructive component testing, such as x-ray analysis to see if any of the structural components experience or caused cracking. The military used to call this NDI testing - which was mandatory for critical aircraft components. Also, repeat analysis tests, such as graduated simulated landings might show you how the components hold up over repeated landings. Just a few thoughts.

[@gijoe1of3]

I have no knowledge of aircraft engineering but find myself loving your videos. It is great to see an airplane coming together from your ideas. Keep it up!

[@JerryRigEverything]

So close to 100k!!!

[@iamthesentinel584]

This videos are incredible. Keep up the amazing work!

[@aldohattonduran5227]

I love your airplanes.. truly extraordinary!! I'm also a fan of the Velocity/ Canard Pushers.. keep up the excellent work 🙌🏻🙌🏻🙌🏻

[@mikelaughlin4470]

Great work guys, as always!

[@user-ny2bx8ez1c]

You guys are an amazing team.

[@jaredsebring6129]

Excited to see her fly! Great job y’all!

[@oldschoolmotorsickle]

Superb engineering; the nose gear will soak up even a very bad landing. Great video!

[@jmcguire5151]

What about a situation of a side load during a landing?

[@tristandawson6417]

Love the videos! As an aerospace engineering student and pilot, its cool to see some of the behind the scene stuff to get a better understanding of what real world engineering actually looks like! Any chance you guys are planning in hiring interns at some point? 😉

[@Arne279]

Another great video guys, beautiful plane!!!!!!!!!

[@BenTheMagnifice]

You guys should consider doing a scheduled livestream where you go over one component like the landing gear in depth from an engineering perspective and answer community questions.

[@tafaragadze6432]

As a pilot, I can appreciate what these guys are putting into their aircraft. It's honestly astounding

[@shakdidagalimal]

"We're very proud of our accomplishment here, we have gone above and beyond and set a new standard." *smirk won't come off face* hahahaha good job

[@Runoratsu]

Very cool! I love watching your videos and seeing how meticulously you think through, design and test everything. Will you also test behavior with respect to sidewards loading of the landing gear, e.g. on a crabbed landing that wasn‘t fully straightened out successfully?

[@sjaakdebaar9371]

You can simultaniously test the engine mounts when you attach the sandbox like you would do with the engine, and attaching the engine mounts to the “firewall” like on the plane

[@billl7551]

I am hoping they will do a full chassis drop test, but that might come later when there is more than one airplane. Keep up the excellent work Dark Aero Team!

[@earlgreystoke3324]

Impressive engineering! Well done!

[@shahramkhesareh8068]

Very good and intresting,i would wish for your team the best to be happend❤

[@nevillecreativitymentor]

Just honored to be a part of this journey ... even though its on you tube ... WOW WOW WOW

[@mycoolbeernuts6870]

The XB-1 took 3 years to design and roll out - You bros are killing it!

[@bruceyoung1343]

Great job. CONGRATULATIONS

[@johnwausau64]

When you were going to school in Madison, it is clear that you guys spent little time on State Street…. You’ve got it together and are applying all the lessons… scientific method in spades !

[@brianb-p6586]

The "voltage regulator" @7:42 is actually a variable transformer or "Variac"... a cool technical throwback.

[@uowebfoot]

You guys. This stuff is too good to have such few videos.

[@wread1982]

Great idea bro

[@arthurjones9580]

Beautiful engineering!

[@palletcolorato]

Fascinating!

[@rjwohlman]

Slick designs!

[@RenTheOriginal]

Just incredible

[@ValFox28]

Plane is definitely high up on the wish list. Best plane out there - so far! Let’s see how she performs during flight tests. Loving the methodical engineering approach though. Instills lots of trust.

[@xeriotti]

Great job!!! But the biggest danger is beign overlooked... The ULpower engine need lots of work before its SAFE. Its not safe out of the box. (Poorly designed Cylinder to HEad Gasket System that leads to leaks, lean running and piston breakup, Neglected Bolt Torques all over the engine, lack of a detonation sensor or lambda probe leaves correct fuel-air mixture to basically atmospheric pressure and luck) 8/5/2023 I hope you guys listen to my advice, check those things... UL Power user myself.

[@suburbangorilla5515]

Professionals in action!

[@victorbarrios5162]

Love these video's. I was wondering, if the test rig is deforming and slowly breaking, is it consuming part of the energy that should go to the landing gear for repeatable testing?

[@johnsmithh662]

As a collective, what is you guy’s mindset when the thought of “what if this doesn’t work out”. You are all inspirations to us. Praying for these guy’s success. Clear blue skies, gents.

[@terke1230]

As always a great video with solid engineering principles. Watching the drop test with the spun up tire, your compression works nicely. However, the rebound landing appears to show no compression, but bending instead. Have you done drop test with the wheel stationary? This would simulate a secondary landing from a bad wheel barrow landing.

[@firedog1116]

Excellent!

[@israeloluwagbemi825]

I love this 👍... Please in performing the load test of an aluminium wing, I'll like to know the time frame used in simulating the loading conditions at 2G, 2.5G 3G, 3.5G, 4G and ultimate of 6G. Thanks.

[@mikhailjairnisbett441]

When I see these videos they get me excited to build a plane!

[@mikenorman4001]

Are you accounting for the flexion of the forward weight box? How does its motion, and its associated energy absorption, compare to the structure of the actual plane? My intuition is that the nose of the plane, and the engine, will be more rigidly attached. If so, you might not be seeing a good approximation of the actual worst case landing in your tests.

[@chester8420]

I doubt there was any real engineering data collected here. I suspect that this "test" was slapped together mostly for entertainment and or content.

[@kf4293]

Very cool. If you get bored on your weekend, I need a nose gear for my Flitetest Mini Guinea. I've trashed everything I've tried. 😉 Doesn't need to retract, but it does need to steer and absorb beginner landings (read: crashes) of ~600g foam airplane. 😂 My goal is to keep it under 20g, including the 5g servo for steering.

[@fettlerjohn3419]

Excellent 👍🏼 ✨

[@A.J.1656]

I'm always impressed when people move their hands a lot when giving a presentation.

[@rotaryperfection]

Awesome!

[@TheeAthis]

Pro all the way!

[@cadenfabbricino7039]

looks cool

[@user-gv7zi8kp5k]

please upload the video of you guys modelling the landing gear on the onshape.

[@GS-wx5pr]

EXCELLENT

[@janoshorvath9430]

On one hand I wish to see the plane flying already, on the other hand that would mean no more such videos... Good job again! :)

[@electricaviationchannelvid7863]

The Velocity aircraft could use a fuselage-retract gear system similar to this in stead of the wing bay setup...

[@fudogwhisperer3590]

What a time saver and easier than replacing all those seals and needing nitrogen to pump them up. Great design! I also noticed no shimmy dampener, how were you able to eliminate that from the design? It appears to be a swivel castering set up and not steerable.

[@Endelin]

I also use those blue Irwin clamps for everything.

[@johnfitzpatrick2469]

Hello Reilly, River and Keagen from Sydney Australia. Thank you for the detailed demonstration and explanation, for the design and testing of your landing gears effectiveness Learning outcome * R&D is time consuming and expensive: mandatory for certification. *.Substitution: weight of engine to avoid damage. * Using a voltage regulator ( AC/DC within the specified motor range). * CAD software 🪃🌏

[@1972C182]

Hi Dark Aero. Will you explain at some point how you will test for side loads and twist loads on the gear during landing? Sometimes the wind can be howling from the wrong direction and you’ll land while both slipping and drifting. Thanks for the many great engineering lessons.

[@TheJustinJ]

The limiting item is tire grip. You're not going to see more than 1g laterally. Even a corvette with wide tires can barely manage 1g lateral grip. So, as long as the gear can handle the weight of the aircraft sideways. On that hears long lever arm. It will be fine.

[@Krasakkrusuksimaul]

i like your descripe, how to use the landing gear match a procedure

[@freddykoopmans6985]

nice testing, this was a heavy landing test in perfect conditions does the regulation also ask for a test with the wheel turned 30 degrees to the centerline or something like that,( last-second corrections with the ruder). if it is not required that ok but just curious about what parts fail, on my airplane after I survive a bad landing.

[@parrotraiser6541]

Landing gear behaviour is especially important on high performance aircraft. Incorrect damping turned a successful landing into a fatal collision with a hangar near me, (Unfortunately, I cannot remember enough details for a proper citation,)

[@harrie205]

love youre content/ Project how much flex on the mock up engine is acceptable(seems to flex a lot)

[@asaiyannamedgokublack]

The dark aero with a Turbo Aero 200 hp turboprop would be a dangerous combo

[@TheOwenMajor]

It's not pressurized so you wouldn't see much improvement, just more fuel burn with a turboprop.

[@mikhailjairnisbett441]

it would make no difference, the engine already makes 200 and the plane isn't pressurized to fly high enough to take advantage of that.

[@alexanderarnett4966]

The Turbo Aero is still a ways off, but if and when it get’s released I suspect this question will get asked a lot more. As for the supposition that a dark Aero would not benefit from the TA200TP (if it delivers on its pro forma specifications), I disagree. Fuel economy would suffer but maybe not as much as one might think. As for altitude, supplemental oxygen is widely available in civilian aviation. It’s technical viability would probably has more to do with an owners preferred routes. If someone can afford a TA200TP vs a UL520iS and all of the other needed modifications, fuel cost is probably not as big an issue as range. A perhaps less costly upgrade would be the UL520iT (Turbocharged Version) it is only slightly larger in z-axis and a few inches longer. Still a new engine cowling would need to be designed, and a 1000 other things adjusted to make it work. It instills a weight penalty and an additional scoop for the intercooler but it would improve the the climb out to 20,000 ft which might make up for the added weight and drag. UL is planing later versions with big power boost. But initially this turbocharged version only maintains power to a higher altitude than the non charged engine.

[@jimsleestak8012]

My dad worked for the Huge Aircrash Company. They had a vibrating platform for shaking the crap out of their components. He never let me have a go.

[@jnewton6]

Would love a test to destruction to really see what it can handle!

[@SeanFChannel]

Cool. One question, several follow ups. Do you have any concerns about the airframes ability to handle the max load drop testing in both the nose and main gear drop tests? I consider the airframe and the gear as being integral when it comes to landing loads for the airplane (product). By only testing the nose gear assembly, does that perhaps leave some unanswered questions as to the overall durability of the airframe. I realize I am being a little obtuse. I don’t mean to be. I understand that the required budget of testing this thing to that level is enormous. Im sure you have thought of these issues. I just wanted to spark a conversation around it in order to understand your thinking on the matter. I am a huge fan of yours (as you know) and the airplane. I really enjoy the videos. But the DarkAero’s wing loading is not low, and it is a new design, so hard landings over the life of a DarkAero builder could be at least as frequent as they are in existing similar aircraft (some metal, others fiberglass, some carbon). That said, perhaps the long term strength of the airframe (and the landing gear assemblies) is an area which needs additional clarification. Thanks. Sean

[@FINNIUSORION]

wish i would have had gear like that during my first solo lol.

[@RealJimSkinner]

3:24 Is there a seal to keep contaminants out of the plain bearings for the strut tube, or is it just open?

[@andy_litak]

You guys are super good!!! glad to follow you, What other tests will you run? I would like to see simulations of bad landings and destruction results on the computer. For many people this would be decisive in deciding to buy your kit, given that other manufacturers do not provide such information.

[@SoloRenegade]

why would you demand such high standards of DarkAero when you admit not demanding such high standards of others? They've already shared more than others do. Maybe you should be posing your demands to those other kit manufacturers instead?

[@user-mi6co1ky3i]

@@SoloRenegade I'm sure it would not cost them anything to run a computer simulation, which would make them stand out even more from the other manufacturers.

[@fubarbazqux]

Do you test what happens in icing conditions? Whether it gets stuck.

[@TijsMaas]

Thanks for sharing! The last test shows rubber wheel deformation: it's squeezed against its tight metal holder. Could this cause the plane to tip over on a hard landing? (Engineer, no experience with landing gears)

[@orvjudd1383]

Did you stain gauge your components on the nose gear to determine if any permanent deformation occurred? I would expect that the wheel fork specifically may experience some permanent set due to the offset of the fork.

[@dylantran2319]

Just out of curiosity, will you guys be updating the propeller shape with the recent toroidal propellers improving efficiency, noise, etc?

[@LiftPizzas]

With the fork being as narrow as it is, I was imagining a hard landing and thinking the tire bulges out to the side and contacts the fork. This is something that wouldn't show up in your testing rig unless you used a slow-motion camera to check for it. (In the rig both ground contact and fork contact are doing the same thing, where in reality both contacts would be doing opposite things.) That is, if the tire is able to bulge, which maybe it isn't, but what if it's a little underinflated and/or you're not landing perfectly straight? Just thinking out loud. :)

[@brianb-p6586]

Tire contact with the fork seems like a valid concern, but it would probably leave visible marks.

[@henrychan720]

How did you test for side loading from steering and crosswind?

[@dinky9216]

Can you adapt the rig so that you can test for when the wings aren't level? That could significantly change the forces.

[@xp46290]

Have you considered the event of a flat nose strut and flat nose tire, will the prop hit the ground in this scenario?

[@maegenyoungs2591]

These guys leave no room for problems, everything has a backup to the backup

[@omnagar8225]

i am keen to know how you guys do the validation of the composite parts computational test and real world .also how you guys find out the life cycle of the aircraft computationally?? Also i am a bit concerned about the stress concentrations on the corners if you are placing your landing gears at the corners because these areas are usally the location of the longerons?? however as an learning aircraft designer myself i am very glad to lyou guys for making such videos its great informative and fun!!

[@TheJustinJ]

Look at any composite fatigue data and you will find a break in the curve that shows if you keep strain below a certain threshold it will have nearly infinite fatigue life, beyond 10^8 or 9th. This is somewhere in the mid hundreds of microstrain for many epoxy-based composites.

[@fixento]

Why not use a shock that you can adjust preload and rebound, like the do on motorcycles?

[@spqba747]

since the plane got ready to be prep for painting the project literally stopped. how much more sanding? another year?

[@deffender80]

There was a lot of deflection in the wooden box holding the simulated load. Wont that have a cushioning effect on the impact load? I would think a re-run with a more rigid material holding the simulated weight load is needed.

[@johnclocke]

Is a DarkAero 2 FG a possibility in the future?

[@RafMov]

Thank you for sharing! Good job however test bench broke and absorb some amount of energy. I believe you did final test with reinforced and more stiff one to be on the safe side 🙂

[@GrizzlyBCool]

When can we see this masterpiece for sale?

[@PaulAnthonyDuttonUk]

What about the drop test for a pilot falling off the wing?