Devil is in the Details (Lean of Peak Aviation)

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  • Опубликовано: 12 сен 2024
  • Investigating and proving what caused a major control system failure in my Sonex Onex.

Комментарии • 93

  • @JoystickTX1
    @JoystickTX1 Год назад +5

    I use a rod between my tailwheel horn and rudder horn on my model planes, but it does transfer shock loads from the tailwheel to the rudder. That can cause the rudder horn to come loose or it can damage the rudder hinges. I have noticed more damage than the springs that I used before.
    On GA planes, springs would be way better and much safer.
    I'm glad you found the root cause before you lost rudder control.
    People need to really be careful when they change the design, even when they think it's a minor change.

  • @milehigher00
    @milehigher00 Год назад +2

    Our Sonex, has the "upgraded" link with the ball ends, this was chosen for the vary reason that has been mentioned by others. The standard link does not freely allow vertical movement from the flex/spring in the tail wheel shaft. This produces unwanted flex and wear on the cranks/attachment points that could lead to stress failure and free-play in the assembly. The ball end link moves freely with the vertical movement of the tail wheel while providing a slop free connection. If the "upgraded" link has the exact same measurements eye to eye and the geometry matches the standard design as well as being attached as per the plans it allows full and free moment of the control surface. The addition of a washer larger than the hole ensures if a ball ever failed the control rod would stay attached but would now have some freeplay but would not be a catastrophic failure. The argument that the original design has been in use for 30 years without any known failures is valid but it does not mean that it cannot be improved if done correctly.

    • @carleldridge8317
      @carleldridge8317 10 месяцев назад

      I agree, the Heim Joint push rod is definitely a better engineering solution, that being said, the fit up and top mount was not a good choice by the original builder, nor was the failure to fully study the action of the push rod at the end of travel!!!

  • @SoloRenegade
    @SoloRenegade Год назад +4

    awesome you took the time to test the old and new parts to show the differences.

  • @bobjoatmon1993
    @bobjoatmon1993 Год назад +7

    Having helped build three Experimental aircraft I found that sticking to the plans is hard for the personality of the average builder BUT the plane should be built to spec because the builder probably doesn't know all the engineering decisions that went into the design. The NTSB has many accident reports where an experimental aircraft design was as good as a certificated airplane but poor workmanship or minor changes introduced by the builder lead to crashes and/or fatalities. I walked away from helping one builder because he just cut and threw the fiberglass on any old way (to economize on material evedently) instead of orienting the strands properly for the loads. Luckily he ended up abandoning the project (a divorce during build) and the plane was scrapped.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +1

      Very good comments.

    • @davidpawson7393
      @davidpawson7393 Год назад +2

      Construction may not be that glamorous but not properly bolting ledger boards to band boards, rim joists or whatever term you may use is where I've drawn the line a few times and I have no problem calling the building inspector. You'd think after a rash of deck collapses with fatalities at a time where people paid good money to enjoy the paradise I was lucky enough to live in, Outer Banks of North Carolina, you'd at least protect yourself and reputation by bolting every other bay but nope, slap it up and on to the next one. These decks are very high as just the first floor is eight to 14 feet above ground level so add two or three stories a hot tub also not installed correctly and you get my point. My decks were usually cantilever with bolts in every bay which isn't required but I enjoy sleeping soundly.

  • @FlyMIfYouGotM
    @FlyMIfYouGotM Год назад +1

    Aviation is a very unforgiving environment that won't tolerate carelessness for long. Attention to the smallest details is a must.

  • @joseruiz-Joecool
    @joseruiz-Joecool Год назад +2

    I am glad you were able to find this mistake on this airplane when you did. Looking foreword to the flying videos in the future.

  • @davidmangold1838
    @davidmangold1838 Год назад +4

    Wow, it’s great you caught that! I’d look for other non-standard parts that the builder may have used. My friend just bought a Velocity, that a great builder built. But, one has to become intimately familiar with what the builder built!

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +1

      You are so right! A Velocity is not a forgiving airplane if something major goes wrong…but what a cool design.

  • @excellenceinanimation960
    @excellenceinanimation960 Год назад +1

    Wow it looks so similar! Scary how such a small change can have such a huge effect!

  • @crikitaviation
    @crikitaviation Год назад

    Builders sometimes forget the saying "Safety in Numbers". Anytime you modify your airplane and deviate from what everyone else is doing, you put your name at the top of the list for problems that may occur because of your modification. Always better for your name to be somewhere down the problem list and hope that someone else will experience a problem or failure before you do. Think about that every time you make a change no matter how small. So glad you caught this. WOW.

  • @danielbasovitch5087
    @danielbasovitch5087 Год назад +2

    In other words, there now are NO Swivel Balls in the connections to allow for vertical rotation of the control arm!

  • @earlgreystoke3324
    @earlgreystoke3324 Год назад

    Sonex has designed failure into this tailwheel steering system. The rigid connecting rod between the tailwheel & rudder horn loads the rudder horn & hinges when the tailwheel support rod deflects under load.

  • @Wolves200
    @Wolves200 Год назад +3

    Hello, nice videos, the shimmy on the tail wheel is not coming from the play on the bushing, is coming from the caster angle-

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад

      Completely horizontal right? I noticed their newer design is more like 45 degrees.

  • @sganzerlag
    @sganzerlag Год назад +2

    Ok so what happens when the tailwheel fork flexes due to landing loads and uneven rolling surface? How does that flex affect the fixed tailwheel control pushrod? I don't see how the new pushrod can account for the fork flex during tailwheel suspension action.

  • @GlensHangar
    @GlensHangar Год назад

    As someone who spent a year tearing down and rebuilding a 1961 Cessna 172B 'certified' aircraft... Don't let 'certified' / 'passed annual' give you all of the good feels, while putting down homebuilders as corner cutters.
    We found 60 years worth of non-standard parts and repairs in the 'certified' airplane.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +3

      That’s precisely why I sold my 172. My mechanic on my certified plane almost killed me and charged a fortune to do it. Sonex is a good airframe and built properly is as safe as anything in my opinion.

  • @DennisZylstra
    @DennisZylstra Год назад

    GREAT VID. Loved the testing. Was wondering if you should redesign the way the tailwheel hooks up to the rudder. I like a spring on the RT and LT side to eliminate any vibration or hooping pressure on the rudders control arm produced by the wheel hitting things. Seems to me a very bad design. Keep up the good work!

  • @mylesvrooman3709
    @mylesvrooman3709 Год назад +2

    If you don't wish to replace the whole Tailwheel castor, you could use a larger diameter bolt to attach the control arm, or you could use a bushing to tighten the hole up to your specs.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад

      For sure. It’s not just the control arm though the caster’s pivot is also too big and non standard.

    • @michaelmartinez1345
      @michaelmartinez1345 Год назад

      @@LeanofPeakAviation I think that Myles Vrooman might be referring to the #8-32 screws that are used for a pivot on either end of that offset push/pull rod... Personally, I still feel that this design is flawed... Yes, the devil is in the details, and if you look at several other planes with steerable tail-wheels, and nose-gears , many of them use bungee springs that are attached to a pair of control cables / linkage going to the rudder... In this way, the rudder can still be operated in the event the auxiliary wheel should freeze-up... And like Myles, I also feel the Tiny #8 screws should be used for fastening adel clamps and clamping down light avionic equipment... Those bends on both ends of the push/pull rod they just sent to you have no gusseting where the angle is created.... If I was to design that plane, I would have made sure the control horn is directly inline with the pair of cables operating it, and any mechanism operating a steerable tail wheel would have bungee springs allowing the rudder to move independently from the steerable aux gear, like many other planes have had for a very long time....

    • @michaelmartinez1345
      @michaelmartinez1345 Год назад

      @@LeanofPeakAviation the documenting of things is always a good idea... But being that this is an experimental aircraft, that would alleviate huge concerns for a liability case against any parts provider, as the plane was mfg'd by the pilot....As far as the flexing of turning forces, from side winds, and suspension rebound, or if the linkage does become damaged from forces like these, it is ALWAYS a good idea to isolate the rudder controls with a bungee springs... This is WHY most tail and nose steering mechanism's have two cables going directly to the rudder and two bungee springs on dual cables going to the auxiliary wheel .. Several builders have eliminated the steering linkage going to the aux wheel and just have light centering springs going to the aux. wheels ... They use differential braking at slow speeds and when the aux. wheel is off the ground as the plane rotates, the rudder is in complete control....

    • @michaelmartinez1345
      @michaelmartinez1345 Год назад

      @@LeanofPeakAviation that is totally understandable.... Maybe the things that you have learned from this purchase could be a great aid in identifying a good plane to buy...

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +1

      @@michaelmartinez1345 No kidding.

  • @julesviolin
    @julesviolin Год назад +1

    There's bodge monkeys everywhere.
    Just hope they don't work on airliners I might fly in someday 🙏

  • @salamander5703
    @salamander5703 Год назад

    If the forward bolt position (measured at 3:19) is off laterally, maybe it is also off fore/aft. There is no adjustment in the factory link, so if the hole is off the tailwheel may not track straight. Which is maybe why the previous owner made his own link with Heim joints for steering adjustment?

  • @yetiatlarge555
    @yetiatlarge555 Год назад +1

    What grade of connecting hardware did you use are you using Teflon impregnated nuts is there any spec for a sleeve where where that undersized bolt is moving around

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +1

      The plans call for aircraft grade cadmium plated hardware with various AN numbers…the pivots are AN23 and the big one is AN6. The use a castle nut and cotter pin for security. I could use make a bushing but I’ve ordered replacement parts since I just don’t know how much adverse force has been applied to these other parts.

  • @SimonAmazingClarke
    @SimonAmazingClarke Год назад

    I'm quite surprised that they use a solid control link. I've seen various tail draggers with springs to the tail wheel. So it suggests to the tail wheel to turn.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад

      It’s definitely a more solid, direct feel. RV’s use something similar although theirs has built in shock absorption.

  • @louisvanrijn3964
    @louisvanrijn3964 Год назад

    1.
    2:32.. Play is unacceptable. OK.
    Ream the hole in the plate, and turn a small sinter bronze bush that just fits. Play gone. Apply grease to keep moisture away. Idea?
    2. 4:33
    That assemby is designed to fail that way.
    Peak forces on the tailwheel are bringing pounding loads in that rod. These loads under an angle cause the secondary bending moment which is designed to exist in this assembly.
    If you apply an small angleplate between the lower bracket/rib and the skin of the rudder, the moments are coupled off. The lost rivets will not come off again.
    The strength of the sheared-off rivets is overestimated, or the loads not identified.
    Remember that the Avdells, pull-through-rivets or pop-rivets are hollow. These arent solid AD or DD rivets such, as used in in a B-17, Liberator or equivalent, and have only a fraction of the strength.

  • @Spyder6898
    @Spyder6898 Год назад

    I just saw a sonex on barnstormers with the same non-stock control arm mounted on top!

  • @johnlucas2037
    @johnlucas2037 Год назад +1

    The pivot should be as close as possible to the wheel

  • @buckbuchanan5849
    @buckbuchanan5849 Год назад +1

    Now I’m wondering what other “design changes” the builder performed that may impact your future flying?

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +1

      I’ll be looking.

    • @PetesGuide
      @PetesGuide Год назад +1

      @@LeanofPeakAviation please make videos of you looking. This is an important story!

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +1

      @@PetesGuide Good call. I may try to get an A+P to collaborate with me on a video for that specific purpose

    • @PetesGuide
      @PetesGuide Год назад

      @@LeanofPeakAviation that would be awesome! Is an A&P or IA the right certification for experimental aircraft? Maybe you could introduce us to how the rules are different - condition inspection vs annual, etc. And since you didn’t build it, do you need to get the builder involved in any of the activities per FAA regs? I’ve not seen anyone go into much detail on this on RUclips, and it would be a great service to the community. Oh, and if you wind up opening up and re-riveting a whole bunch of things while looking for problems, might that ever put you over the threshold of 51% of the build, triggering the slightly different set of rules?

  • @peterblacklin9174
    @peterblacklin9174 Год назад

    The surfaces on the link are flat, how does the flexing of the tail wheel arm affect the fit?

  • @DanFrederiksen
    @DanFrederiksen Год назад

    Strange to improvise such a control arm, it's a rather specific design. Could it be that it's just an older sonex design?

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад

      Nope. Sonex tech support was adamant they’ve never used anything like it. I also have the specific serial numbered plans for my plane and the part he used was not correct or correctly placed.

  • @nspctor7729
    @nspctor7729 Год назад

    Where else has this 'previous builder' deviated from the plan?

  • @shademe
    @shademe Год назад +1

    nice series on this thank you for sharing. Also if this was built incorrectly that would scare to 💩 out of me and I would check the whole plane I'm sure you have thought of that already. good day

  • @bryancotton7279
    @bryancotton7279 Год назад

    Regarding the tailwheel - I've got the stock tailwheel on my Waiex and it seems fine to me. I know a lot of people want to upgrade it, but I don't see the need. I fly off both grass and hardtop.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад

      Thanks for the comment! Haven’t had many Sonex owners speak up. Appreciate it.

  • @pilotblue6535
    @pilotblue6535 Год назад

    Try using an OILITE Bushing from Aircraft Spruce. They are a self-lubricating oil-impregnated brass bushing for your situation.

  • @masonallen3901
    @masonallen3901 Год назад +1

    I dont know about you but I dont want a landing gear anywhere near my rudder...

  • @onthemoney7237
    @onthemoney7237 Год назад

    I’m going to check my Sonex tail the next time I get to the hanger I’ll let you know thanks if you find anything else or think of anything let us know thank you 👍

  • @dermick
    @dermick Год назад

    It sure looks simpler than my RV-8, but how do you swivel 360 degrees with that tailwheel? Does the tailwheel free up at some point? Installing an "action" camera back there in a safe place would be eye-opening. There's a lot happening.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад

      There’s no 360 swivel. When you reach the rudder stop you’re done…which is totally fine you’re just not going to do ground turns in place.

  • @SoloRenegade
    @SoloRenegade Год назад

    you could create a bushing for the bolt hole short term, but may decide it's not worth the effort if you're replacing the tailwheel assy anyways.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +3

      Yeah I thought about it and I think I just want everything to go back to plans.

  • @tdavidgraham8675
    @tdavidgraham8675 Год назад

    Looking at that, I would guess that the problem link was made to mount above the rudder horn and at the bottom of the tailwheel horn. Playing devil's advocate, some mechanics have a real aversion to having a rotating metal plate under a bolt head as you say the factory link is supposed to assemble. Too much play to start with, and then extended wear would make the problem worse.
    Whoever made the link with Heim joints was probably wanting a tighter grip on the bell cranks and and an oiled ball wear surface that will allow for misalignment when turning...good idea.
    It would be interesting to see how that Heim joint link looks when attached as I suggest above.
    I wonder why Sonic did not use a double spring steering common to most taildraggers.
    Any rigid link will transmit loads while taxiing back into the rudder Keep an eye on it.

  • @johnelliott4521
    @johnelliott4521 Год назад

    Makes me wonder how it passed initial inspection

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +1

      I’ve had a couple bad experiences with different mechanics now. Just because you pay someone a ton of money to inspect your plane doesn’t mean they’re gonna keep you safe. Fortunately I’ve learned this lesson without being on the local news.

  • @danielbasovitch5087
    @danielbasovitch5087 Год назад

    With Just bolts attaching the horn to the wheel assy how does it swivel when a load is applied in a down force to the tail wheel arm?? The tabs are just flat surfaces.

  • @jimlove4541
    @jimlove4541 Год назад

    It looks to me the control rod is going to act like a second torsion bar and will put a twisting load on the control horn. It's hard to see ,are the attaching points on the rudder horn the same distance from center Left and Right? For pull pull cables they should be the same, it looks like a lot is going wrong with this setup.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад

      Sortof an illusion. The cable pivots are equidistant to the rudder hinge but the rudder hinge itself is not centered on the rudder. It’s a one sided hinge on a triangular rudder.

  • @antofagastaride
    @antofagastaride Год назад

    How will the new ( standar? )control rod absorb the flex in the support bar of the tail wheel? Also you are going to need those spherical.joints to negotiate that. You risk breaking the rudder control horn leaving the craft ruderless!!! That's why you need springs to control the tail wheel, to absorb all the differential play among parts without overstressing any.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +2

      Sonex has been using this design for 30 years and this is an isolated incident with nonstandard parts.

    • @antofagastaride
      @antofagastaride Год назад

      @@LeanofPeakAviation may be that's why the former owner made a mod. You better ask him. Just a suggestion.

  • @davidpawson7393
    @davidpawson7393 Год назад

    Translation, don't Walmart shopping cart your future Blancolirio video by Jiffy Lubing your class that's under enough scrutiny as it is.

  • @Jack-ne8vm
    @Jack-ne8vm Год назад +1

    Amazon sells bags of miscellaneous tubing; brass, copper, aluminum... Bushing material.

    • @davidmangold1838
      @davidmangold1838 Год назад +1

      Even though it’s experimental/home built, I would use approved aviation hardware, not shopping at Tri Value, Amazon or…. Use AN bolts, nuts etc.

  • @stefanmargraf7878
    @stefanmargraf7878 Год назад

    Are you sure, that the backwheel assembly is not meant to be attached 180° turned? (upside down from now?)

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад

      That would place the welded arm on the other side of the plane.

  • @GunniesLetsFlyVFR
    @GunniesLetsFlyVFR Год назад

    I guess my question and concern for you is what else may have been done that's non standard? Does it concern you at all or have you had everything else examined?

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад

      Agreed. I’m pretty much trying to go over everything reasonable and compare to the plans…Critical control structures obviously being the biggest concern, and then anything that might cause a catastrophic failure.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад

      The worst part was it had its annual inspection by a certified mechanic 2 weeks prior to this incident happening.

  • @villagelightsmith4375
    @villagelightsmith4375 Год назад

    Yeah, I had a very nice bluewater sailboat ... all factory build ... nice boat ... but some parts chaser brought back steel instead of stainless in the keel bolts. Details will get you down. Happily, I didn't lose mine on a Pacific crossing! A mess of those sailboats were for sale cheap in a couple years, having sent their keels to Davy Jones' Locker! Details ... they'll take you DOWN! It happens in every industry.

  • @Nord3202
    @Nord3202 Год назад

    The original builder must of had problems with the sonnex stock rod & added rod ends to prevent strain on the rudder horn. You should of used cherry max aircraft rivets on that rudder horn it would of been alot stronger.

    • @LeanofPeakAviation
      @LeanofPeakAviation  Год назад +1

      I hear you but the last guy deviated from the plans with disastrous results. Maybe cherry max rivets hold the horn in place so the rudder hinge fails next time? I think I’m going to trust the plans and follow them since this seems to be a unique failure mode. I’ll make this a regular part of my preflight checklist.

  • @bobchannell3553
    @bobchannell3553 Год назад

    That part wasn't just non standard, it didn't fit at all. Could barely be rigged in. I can't believe people fly in these things anyway. It'd take a lot of nerve to put something like that on your airplane, and trust your life to it. I'm assuming the original owner flew it

  • @jarikinnunen1718
    @jarikinnunen1718 Год назад

    Why not skid?

  • @thekingsilverado3266
    @thekingsilverado3266 Год назад

    Bee extremely careful when U are buying used aircraft period... Some folks will actually fly a defective plane like that to U then sell it to U...

  • @justinparker7795
    @justinparker7795 Год назад

    throw the damn thing away and learn what a rudder is for!!!!!

  • @jacknisen
    @jacknisen Год назад

    Who pre flighted this plane ?