I Just Broke My Airplane Wing Spar - What I Learned | Scrappy #47 

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I put my wing spar design to the test. After designing and extruding my own custom aluminum, I finally get to test it...to the breaking point. Watch as I put all the engineering to the test!
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Published on


May 1, 2021




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Comments 100   
Oh well
Oh well 6 hours ago
Not a twin spar wing and if not why not ????
1DIYGuy 7 hours ago
I feel your test was an awesome way of testing but would there be a significant difference considering the strut is pulling on the spar. I do not know how the strut is connected to disperse the load on the spar vs. the pressure point in the test and would that affect the outcome? Thank you for making me think outside the box.
Kraig Duncan
Kraig Duncan 7 hours ago
Scrappy twin blows engine og scrappy says hop on ill give yah a piggy back ride no need to leave the cargo behind
tim diguistini
tim diguistini 8 hours ago
Would the numbers be different when climbing or diving‽
Paul Schuyler
Paul Schuyler 10 hours ago
I'm not gay but will you marry me?
David Mendonca
David Mendonca 11 hours ago
Fun experiment watching those results. Here’s an option for that 3,000 pounds. You flew search and rescue to help people, put a tank on the belly and fight fires. 😊
Mike Schwab
Mike Schwab 11 hours ago
You want excitement? Try a hydraulic press to failure on concrete.
Mike Schwab
Mike Schwab 11 hours ago
Toss in some lead or gold ingots, you'll hit your maximum.
Frank Leonard
Frank Leonard 12 hours ago
WOW!!!! I am no engineer and am struggling to get my ground school started but I have learned so much from you. I love your content!!! THANKS
Pablo Meelar
Pablo Meelar 14 hours ago
You are brain food, delicious brain food. Thanks. Peace.
Captain Daniel
Captain Daniel 17 hours ago
Like the idea for the waste spars, that's actually pretty cool
hoah 18 hours ago
Last rib was fouling on the wall about halfway towards the target. Effectively shortening the spar by at least a 3rd.
hoah 18 hours ago
Lol at these kooky backcountry measurements. Seven and five eighths? Get real
Great Michigan Bush Co.
Mike awesome stuff and great plane builds, I love what you do! I think it is time to change "Scrappy"'s name. "New" custom built spars are so far away from "scrap" and all the custom made "new" carbon fiber parts have wandered so far away from the "scrap" budget build idea, the full Garmin avionics suite of avionics. This plane is awesome and while I didn't think there would be anything that could rival Draco for an over the top bush pane this one will. The cub-esque look, the crazy propeller, the 8 cylinder engine. OMG this is every back country flyers dream plane they didn't have the ability to to even dream it's so far outside the box. Keep up the forefront aircraft design and building... but can we call it somethimg more in line with what it is? This is by no means "scrappy" we should call it something like "Polished" "Scamp" "Goliath."
Eric Hart
Eric Hart Day ago
I am so grateful you post these on your channel. Thank you for sharing them. I haven't finished this one yet but as soon as you said you increased the width of the spar, I thought that might be an issue that would weaken the spar and take a great amount of thickness increase to take the load. Finishing the video now to see how right or wrong I am....Thanks again. LOL I love the fact that you bought 30....you are an absolute test maniac...LOVE IT!...and humbled to be way wrong...thanks for the education
Russ Montgomery
I just want to tell you how much I enjoy your videos. I learned to fly when I was 12 on my grand dads 46 Stinson voyager and took my solo on my 16th in that same plane (1986), we flew that old bird all over the country until 1997-ish when he had to sell it due to his failing health. I continued to fly (rentals and friends planes) until 2004 when I lost my medical (sad day for me) any way, I recently started flying model planes and it has brought back some of the joy i used to have flying the real thing. I just wanted to share a little of myself and tell you how inspiring your videos are, so much so that my daughter is now talking about wanting to learn to fly and getting her pilots license when she turns 16 (in 4 years) we even opened a savings account for her to save up for flying school. She goes out with me every weekend to fly model planes and is completely hooked, I can't wait to get her in the cockpit of the real thing. Keep up the great work.
Sm b
Sm b Day ago
There's a wing design I've been playing with for some time now I just figured it out. I'd like to introduce it to you and see what you think about it very interesting idea. It has to do with changing the airflow in the front of the wing to make the air go faster over the top. it's a very simple simple design. I would love to talk to you about that and see if it can help you in any way shape or form. She wish to communicate with me send me a message and an email and I will immediately send you my phone number and we can talk on the phone. Love watching your stuff you do the right stuff the right way. This is how I want to build my design as well.
@MikePatey, copy the wing tip of the A-10 Warthog, increased ‘ground-effect’ during landing.
LazyPilot99 Gaming
Just a bad design to start with I think why not use a wing tube or carbon fiber or both ? But I'm sure a lot of people know what type of planes I build
todd prifogle
This episode is most excellent !
Joseph Plummer
Can’t wait to get my scrappy spars.
hhgttg Day ago
In the last test for the Scrappy wing spar, it looked like the far end of the spar was up against the wall? Might be why the spar bent so close to the fulcrum point.
Fred Flintstone
Well at least you didn't get your anchor scratched.
BRS RC Day ago
Tonight he celebrates the wings he's going to have by eating wings with the boys
Joel Sperzagni
It’s like he’s talking to a kindergarten class
Embeded Fabrication
is it just 6061 T6?
Charles Storey
Wow what a pay load, great work , yea Scrappy wings . thanks , .
Gary S
Gary S Day ago
Hi Mike, first off I LOVE your stuff! You are a natural educator & I’m so grateful you have taken the time to share your builds with the world! I’m no engineer but it occurs to me that Scrappy’s wing is going to be high lift & high drag & I was wondering if you have considered using “Maule’s” technique for using minus 5 degrees (I think it is) on the flap setting to dump some lift & drag for a faster cruise? Keep up the GREAT work!
Erin boat guy
Can mild heat treating and or annealing help with a better load rating.....just an idea
Sebastian Rodriguez
I would change comercial aviation for this in a blink of an eye! You do an amazing job, the job of my dreams!
Anthony Overing
With that capacity, you could sling a couple AIM-9 sidewinders under there ;))
Leda May
Leda May Day ago
BUT.. Will it do LooptyHoops? haha
Leda May
Leda May Day ago
Lead Sled
Lead Sled Day ago
Why not a carbon Spar or carbon wrapped ?
John Fossett
John Fossett Day ago
I watch this at least 3or4 times.....and I Like to review Graco one through scrappy 50 it’s like déjà vu all over again
beetlebailey Day ago
Great job and very interesting video ...thx for sharing mike also how do I sign up to win one of your give away draco rc planes ? Thx so much !!
Chalmich5 Day ago
As an amateur engineer, I geeked out so hard on this video. I feel we both shared the same level of morale and motivation watching this. You're the Elon of the sky, keep on keeping on 💪
B H K7 AZ Day ago
Beautiful piece of work - you had me when you said FEA and SolidWorks... just curious how you evaluate the extrusion metallurgy for spars - i.e., what tests does the extruder (or you) perform to ensure consistency of the metallurgy along the length? Other thoughts (I was in new product development for 40 years as engineer/manager/director/GM) include how many test samples are enough when your life depends upon it? I am not nitpicking, just love watching and hearing how you apply engineering to the design of your aircraft. Thanks, Bob.
Scott McLain
Scott McLain 2 days ago
Is that a Celestron NexStar telescope in the back room when you are showing off the anodized spars?
Chloe Hennessey
Chloe Hennessey 2 days ago
4:30. That Bell behind you is gorgeous. I love vertical flight more than anything in the world.
Kevin Gaudon
Kevin Gaudon 2 days ago
Wings , yes finally , wings!
Keith Cress
Keith Cress 2 days ago
When the spar doesn't return to zero is that because it's started to yield? When it starts to kink out of the plane would that be "column buckling"? Congrats Mike on your successful spar design!
eric henslee
eric henslee 2 days ago
o with such a strong spar why not go strut-less?
cmibm 2 days ago
Hey Mike. I have followed this project and I am deeply impressed. The body work you are making is exquisit. OK, you have obtained the desired result of relative strength - and that may be good enough for your purpose. But it seems to me that something is wrong. There are so many considerations behind this that I don't know of, so I may be completely out of line. But in my world it should be possible to bend such a spar/beam to a significant permanent deformation WITHOUT having a fatal fault. So it seems to me that the profile is less than optimal. I would consider widening the flanges up to a size where they do not collapse. This will add some weight that can be removed by drilling some fairly big holes in the body of the profile ( and by having fewer ribs). Further I wonder why you are only talking about static forces. Even a plane like Scrappy can encounter severe turbulence, resulting in 3-4 G's. None of my business - I am not going to fly with you - but I felt a need to share these thoughts with you.
911s73targa 2 days ago
Ever tought of a titanium spar? like the F14 had a titanium wingbox, that thing was indestructible
911s73targa 2 days ago
Mike, you're a total Geek (i mean that in a good way)
David Ewing
David Ewing 2 days ago
SI units make a whole lot more sense.
1978grizz 2 days ago
I really think this is my favorite episode yet. I love watching the testing and explaining of Scrappys parts. All of Scrapoys strength is great but it's gonna cost some money. I wonder what scrappy final cost will be?
Peter Fox
Peter Fox 2 days ago
any different results if you used a doubler with more bolts as would be in a real spar and strut attach point ? the high point load on the test rig might lower the yield value ?
sadeq rafeapour
sadeq rafeapour 2 days ago
Hi you can add small wings on the top of the weels just like a mudguard,be sure it's work ,saadeq from iran .góodluck.
Mike You are Sooo Cool! So Close ro Perfection! So Fun to Watch your channel. Love your idea with the Scrap pieces and Absolutely Love that Orange Scrappy Cut out! Can't wait to see those Wings! Not a Pilot but a Huge fan!
Michael Czetyrbok
What a great day for you Mike! Fantastic results!! Congratulations, my friend!👍🏻🥃
Brian Fussell
Brian Fussell 2 days ago
I really dig the Happy Go Lucky/party time/let's have fun and get to work Mike Patey, but the Serious Engineer Mike Patey in this video @ 6:28 got My attention. That is the "This Ish could kill You if done all wrong" kinda thing that makes Me pay attention. I can't wait till Scrappy is airborne. (buying a Scrappy shirt and sticker now).
Doug Bourdo
Doug Bourdo 2 days ago
Awesome. Simply Awesome.
Matthew Prather
Matthew Prather 2 days ago
Are you saying the scientists and engineers know what they're talking about??! Who knew! lol. :)
Daniel Av8tor
Daniel Av8tor 2 days ago
Myth Busters aviation style. The Patey effect
ChaosTVAfrica 2 days ago
Please build a space skimming rocket ship
Donald Kelley
Donald Kelley 2 days ago
I would think you would use a honeycomb triangular tube instead of I-beam which, we all [should] know, wants to go to the side when you apply force in that direction. I mean, wouldn't you want a spar that never bends or breaks?
Donald Kelley
Donald Kelley 2 days ago
I am seeing testing that is not representative of real world situations; I don't believe the rear or the front wing struts will be taking loads by themselves, so testing them alone only gives you data as it pertains to one strut. This is valuable information to start with but, do you plan on testing both struts together to come up with data that's more representative of what your expectations were?
Peter Koopman
Peter Koopman 2 days ago
Did he recently develop a speech impediment? Don’t remember in previous videos
Jim Seals
Jim Seals 2 days ago
Mike this is another great presentation! I thoroughly enjoy and appreciate your work. Looking forward to seeing Scrappy fly!
randy greer
randy greer 2 days ago
Validated Model for that cross sectional stress strain test, Hysteresis is next, use a cam with your deflection just for a stress strain, work hardening profile, then notch/nick sensitivity.
Vincenzo Ciffa
Vincenzo Ciffa 2 days ago
Seeing as the failure of all the spars was bucking along the bottom flat of the “I” if you added thickness along that how much extra strength would that add I wonder.
lee adams
lee adams 2 days ago
Interesting? No, Fascinating...a little late watching cause of computer death lol...but as your the carbon fiber expert I was wondering why you did not go to a carbon fiber spar and carbon fiber ribs? Is there a reason that aluminum is better than carbon fiber in that application? If all is the same or similar would the manufacture of the carbon fiber be time prohibitive? Hopefully you will address this as now you have got me wondering...again thank you for your efforts at aviation education and invention. Superb video.
Aaron Unterseher
Aaron Unterseher 2 days ago
Mike you seriously should consider being a college instructor or even private... I'd actually go back to school if I had you as a teacher or someone like you!
David Wiebe
David Wiebe 2 days ago
The rear spar on the carbon cub stayed bent at the same deflection as the front, say 6.75 inches. So a bent wing might still have the correct angle of attack. On Scrappy they are mismatched. The front stays bent at about 6 inches. Excessive positive G’s would leave the damaged wing with increased angle of attack on the tips... aerodynamically unsafe at stall speeds. How many G’s would it take to damage the front spar (with a full load of gold bars of course), and can a human survive this?
fabriglas 2 days ago
Whats the hydraulic link between the ratchet and the scales?
Oneofurfriends 2 days ago
this plane is fake and just cgi...drop it off at my house to prove its not
Dan ONeal
Dan ONeal 2 days ago
Mike wouldn’t the wing strut absorb some of that? And If so how much would it or could it take. The wing strut wouldn’t be as rigid as the steel bolted to the floor. Also the strut is angled and how is that affected?
HotelPapa100 2 days ago
Since the failure mode is buckling, i.e. the compression side, shouldn't you also simulate the forces along the spar that are induced by the oblique force brought in by the struts? I have no idea how high these stresses are in relation to the bending stresses, but the force itself is a multiple of the vertical reaction force taken by the strut, given its flat angle.
Matt7AC 2 days ago
I would like to see this test done on a wooden spar. Just to see what happens.
Dennis Barton
Dennis Barton 2 days ago
AWESOME! Are you considering 'CRYOGENICALLY' treating the Spar too?
Victory Autmotive
I notice that a lot of times you only use peel ply when doing carbon. What drives your decision to not use vacuum bagging?
Bob longdickder
Bob longdickder 2 days ago
I'd say you learned you were a genius
Man I love this channel.
S lam
S lam 2 days ago
Okay!!!, maybe now we can start to see some wing building. I am sending video link to my past boss who is a mechanical engineer. Tom will enjoy this. He is working on making oxygen on Mars.
@23:18 Hmmm, so if I bend my wing in the back country, can I cut out the fabric, smack the bulge with a hammer and throw some duct tape back over it?
Luke Orlando
Luke Orlando 2 days ago
God forbid mike ever crashes again. But if he does he wants to make sure the earth bends not his plane
brian young
brian young 2 days ago
Nice work.
FEDERICO 2 days ago
Scrappy will be able to fly in reverse?
FEDERICO 2 days ago
You are a Master! You and Howar Hughes' money would allow every man on earth to fly daily for the price of a Tesla within 5 years!
Donald Grosz
Donald Grosz 2 days ago
Would carbon ribs offset the added weight?
I've been an airplane nut my entire life. I learned more about wing construction and mechanics in the last 30 minutes than the last 20 years.
The Carpenter Dad
So... if you put a 2x8 Doug fir wood stud beam in your jig 🤔. I wonder what the numbers would look like
skip walker
skip walker 3 days ago
I really think you should build another Scrappy with a Chevy LS w/800 hp. (much more reliable.)
ShuRugal Oorus
ShuRugal Oorus 3 days ago
your main spar failed at a point loading of 900 lbs less than my Mooney's MGTOW... you aren't building a Cub, you're building a Caravan with a Cub disguse.
Wayne C
Wayne C 3 days ago
The wing loading in flight doesnt cause it to fold around the strut point does it? The lift forces push up on the underside of the wing trying to detach it from the strut attachment point?? I've seen wing testing before and am a user of FE, not for aircraft though, so I'm interested in why you are testing with what appears to me to be loading on the wings upper surface. Thanks for your time and these very interesting videos.
Wayne C
Wayne C 3 days ago
OK, just heard the downward shock/fulcrum explination which answers everything, maybe I'll watch the whole video before asking questions next time!!
Michael McNeil
Michael McNeil 3 days ago
I hope you don't kill yourself. Does't the point of failure depend on how often the deflection occurs?
name not shown
name not shown 3 days ago
wing spar loads will be spread over the wing length, pulling at one point is analagous to the wing hitting a pole at speed at that point, not realistic to how the wing actually works in the air. Better method is to spread the load over the wing, puting weights at set intervals across the wing will give more realistic results.
DR McKinley
DR McKinley 3 days ago
Mike: check out on US-first: "Tesla battery day. " great science on processing. Build it test it!!!
Raul Bermudez
Raul Bermudez 3 days ago
Someone gives the “best tugs’ 😝
Philip B
Philip B 3 days ago
“Remember kids, the only difference between screwing around and science, is writing it down” - Alex Jason
john mcgovern
john mcgovern 3 days ago
A good comparison of different spars under that specific test rig but dose not relate to actual wing requirements or conditions. That is load distribution along the wing, twist, flutter and attachment effects on spar integrity.
I remember when you brought Draco to the anchorage airshow thing are you going to do that with scrappy
uncommon logic
uncommon logic 3 days ago
Man is Best, rare group of designers can take designs into the future standards. Great video on FEA, not so techy, it brings reality to engineering principles and safety design. Thanks Mike!
Dale Mullens
Dale Mullens 3 days ago
I've been watching this project a while. Anxious to see first flight. Awesome plans. Rooting for Scrappy.
War Spike
War Spike 3 days ago
I'm so pleased to see such a clear example of engineering test / fail . Man, if I had that back in the day in practical examples in my AE courses rather than just graph paper and TI-80s ... Good work Mike! You should license your content to engineering schools ! Your methodical data collection and excitement you show proving the model is inspiring. (it would also be interesting to measure the force at the pivot point / strut bolt.)
Got Gravel
Got Gravel 3 days ago
Watching you do this is just better than anything Hollywood can throw at me. Awesome as always Mike!
John Morton
John Morton 3 days ago
Gotta love Mr Ron
SO Motorsports
SO Motorsports 3 days ago
Placed my order for the cut offs!! absolutely pumped, it is 100% a dream of mine to fly, sadly in NJ i will never have a bush plane lol