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N127ZP Landing gear failure.

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davidjoyce(at)doctors.org
Guest

Posted: Fri Jun 03, 2011 11:44 pm Post subject: N127ZP Landing gear failure.

Jeff, Bad luck. Very strange that an over centre locked system can collapse. 

My understanding of the Rotax routine for prop strikes is that the gear box 

is taken off & professionally examined & if that is OK then you need go no 

further.

Regards, David Joyce, G-XSDJ

---

pete(at)lawless.info
Guest

Posted: Sat Jun 04, 2011 12:34 am Post subject: N127ZP Landing gear failure.

Hi All



Looking at the pictures the slot for the retract lever looks very wide.

Mine is just wide enough to let the lever slide easily.  It is noticeable

that the gear has collapsed because the lever has twisted and deformed. 



Is there a connection?



Regards



Pete



--

rlborger(at)mac.com
Guest

Posted: Sat Jun 04, 2011 4:45 am Post subject: N127ZP Landing gear failure.

Jeff,



Agreed, failure of the over center lock allowed the gear to retract.  

Rotax has a set procedure for checking the engine after a prop strike.  http://www.rotax-owner.com/all-videos has a general prop strike inspection video and two videos showing the procedure to check the crankshaft runout and to check for crankshaft distortion.  These checks should best be made by an experienced Rotax repair shop.

Looks like you are just east of Rochester.  One of the frequent contributors to the Rotax Engines List is a fellow who operates a Rotax Shop in the Buffalo area.  If I remember correctly, his name is Thom Riddle.  I'll see if I can find one of his postings with contact information.  Here is what information is available:

 	  Quote: 	
		  Thom Riddle

Buffalo, NY (9G0)

Kolb Slingshot SS-021

Jabiru 2200A #1574

Tennessee Prop 64x32 	
You can probably find him through a White Pages search or contact him through the list.



I hope this helps.

Good luck,

 Bob Borger

Europa Kit #A221 N914XL, XS Tri-Gear, Intercooled 914, Airmaster C/S Prop

http://www.europaowners.org/forums/gallery2.php?g2_itemId=60232

http://www.biplaneforumgallery.com/index.php?cat=10046

Europa Flying!

3705 Lynchburg Dr.

Corinth, TX  76208

Home:  940-497-2123

Cel:  817-992-1117



 

 

On Jun 4, 2011, at 2:41, David Joyce wrote:

 	  Quote: 	
		  --> Europa-List message posted by: "David Joyce" <davidjoyce(at)doctors.org.uk (davidjoyce(at)doctors.org.uk)>



Jeff, Bad luck. Very strange that an over centre locked system can collapse. My understanding of the Rotax routine for prop strikes is that the gear box is taken off & professionally examined & if that is OK then you need go no further.

Regards, David Joyce, G-XSDJ

ken carp

Joined: 31 Oct 2008
Posts: 29
Location: Knoxville, TN

Posted: Sat Jun 04, 2011 6:26 am Post subject: N127ZP Landing gear failure.

Had the same thing happen to me but I did not have mod 51.  The tunnel looked like yours too.  I had to replace the prop blades but did not do anything to the rotax.  Maybe should have but all is well 550 hrs and eight years later.  There is a problem with the gear being over center or something like that.  I recall filing on a stop to get it to be just a bit more over center.  You can lift the plane by a hoist attached to the engine.  Suggest a conference with Bud Yerly.

Looks like a beautiful plane except for the damage.



Sent from my iPad

Ken Carpenter



On Jun 4, 2011, at 12:41 AM, "David Joyce" <davidjoyce(at)doctors.org.uk> wrote:



[quote] 

 

 Jeff, Bad luck. Very strange that an over centre locked system can collapse. My understanding of the Rotax routine for prop strikes is that the gear box is taken off & professionally examined & if that is OK then you need go no further.

 Regards, David Joyce, G-XSDJ

 ---

_________________
ken carpenter

rparigoris

Joined: 24 Nov 2009
Posts: 796

Posted: Sat Jun 04, 2011 7:26 am Post subject: Re: N127ZP Landing gear failure.

Hi Jeff



When working on my XS gear of A265, I made a jig and fixture to

observe and allow myself to fully understand how the gear worked.

I was able to make a measuring jig and to my horror my undercarriage

mounting frame was allowing one side to be on center, and the other under center. 

I believe there is a good chance this is a recipe for the disaster you and Ken experienced. 

You want both sides over center by at least 1/16".

There is no mention in the manual of checking this or just how important it is to be over center, but keep in mind not too much over center or you can bend components on the under carriage mounting frame.

BTW on early Classic undercarriage mounting frames there was a mod to add more steel and melt it in place. I forget the number of the mod or bulletin. 

I urged Steve D. to check his, and his needed attention as well. 

I ended up lopped off the stops to allow about 1/8" overcenter, then Reduxed in place a nice piece of hard durometer polyurethane obtained from McMaster in addition to using a #3 bolt to hold the slug of Polyurethane in place. The Polyurethane allows for a small amount of shock absorption, but even if it were to fail, only 1/8" overcenter could be achieved.

it's been a while and I forget exactly how i made my measuring tool, but going from memory now, I made something that went inside the LG08 large diameter pivot that had a pin central located the same diameter as the pin at the base of LG08, which is also the same diameter as the pin (LG04) that the bottom shock absorber plate pivots on.

Anyway you have now 3 pins the same diameter. using a thin steel rule you can measure to see if they are absolute in alignment (which would mean they are on center) or if the bottom LG08 pin is a bit forward (over center) like you want.

Here arew some drawings:

http://www.europa-aircraft.biz/upload/cmb_29m_landinggear_mono.pdf



BTW to save yourself at a remote airport or if you need to get off

runway quick, John Hurst mentioned you could remove right stabilator, remove right wing, take seat cushions on put under fuse, and roll plane on right side, pull gear down, get stuck and then roll your bird off the runway.



Good luck.



Ron P.



BTW looks like Jab, not Rotax, not sure procedure on Jab for prop strike.

fklein(at)orcasonline.com
Guest

Posted: Sat Jun 04, 2011 7:54 am Post subject: N127ZP Landing gear failure.

On Jun 4, 2011, at 8:26 AM, rparigoris wrote:



 	  Quote: 	
		   When working on my XS gear of A265, I made a jig and fixture to

 observe and allow myself to fully understand how the gear worked.

 I was able to make a measuring jig and to my horror my undercarriage

 mounting frame was allowing one side to be on center, and the other  

 under center.


	


Following the advice of Kingsley Hurst, I studied this condition at  

length and I too found that one of the two stops on the LG mounting  

frame needed some filing in order for them to make contact  

simultaneously. As clever and simple as the retraction design is, a  

high level of precision appears to be essential for it to function  

properly.



Fred

rparigoris

Joined: 24 Nov 2009
Posts: 796

Posted: Sat Jun 04, 2011 8:14 am Post subject: Re: N127ZP Landing gear failure.

Hi Fred

When you filed the stops to allow LG08s contact to occur at the same time, did you insure that in fact both LG08s were over center?

How much did you go over center?

From memory I needed to take 3/16" off one stop and 1/8" off the other. There was only a hollow tube left on each side.

Ron Parigoris

gregoryf.flyboy(at)comcas
Guest

Posted: Sat Jun 04, 2011 5:02 pm Post subject: N127ZP Landing gear failure.

posted by: Ken Carpenter : Looks like a beautiful plane except for the

damage.



I was thinking the same thing. Very pretty! Sorry for the damage suffered to

your beautiful bird.  

Do not archive

--

Remi Guerner

Joined: 14 Dec 2010
Posts: 284

Posted: Sun Jun 05, 2011 10:34 am Post subject: Re: N127ZP Landing gear failure.

Sorry for the mishap of N127ZP. 

It is critical that the retraction system is over center against the stops of the frame and remain in this position all the time the gear is down. The factory has improved the original design with the addition of the strut (Mod 51). But  the lower end of this strut being attached to a pin and fork assembly, there is inevitably a play which develops there overtime which makes the mod less effective, possibly allowing LG08 arms to move away from the stops. I designed a variation of Mod 51 which eliminates this defect. See attached pictures. The port LG08 arm is modified with the installation of an aluminum plate glued with epoxy and flox. The lower end of the strut is bolted directly on LG08 with an AN3 bolt. Therefore there is no possible play in the LG08/LG12/strut assembly. 



Remi Guerner

F-PGKL monowheel, 830 hours

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JonSmith

Joined: 21 May 2010
Posts: 110

Posted: Sun Jun 05, 2011 11:25 pm Post subject: Re: N127ZP Landing gear failure.

Hi, I was very sorry to read of your misfortune.  It must be heartbreaking.  With luck the damage to your lovely looking plane will be just the retract handle, strut mod and a new guide plate.  (Engines and props are just bolt on accessories!!) 



Just a few thoughts from me:  As the retract handle is still in the "down gate" the over-centre locking mechanism has obviously failed to do it's job and has let go for whatever reason.  Certainly this should not be able to happen so I feel it must be considered that something was not quite right with your set up.  It may or may not be possible to determine now what it was but either way I'm sure that when you repair and check things it will definitely be possible to avoid it happening again.



I believe that during the initial build (and in the uk, at each annual inspection) there are two critical considerations:



1/  The geometry of the set up must be correct.



2/  There must be no wear or play in any of the system which might allow this otherwise correct geometry to alter.



Nb. The following must be finally checked with no weight on the wheel, ie. aircraft hoisted.



1/ Geometry:  

(a) The LG8 arms must contact their respective stops together and be parallel to each other.  Furthermore when the arms are on their stops the front edge of the retract lever must be hard against the front edge of the "down gate" on which it reacts.  The lever holds the arms against their stops so there must be no gap here whatsoever, just a tight sliding fit so that you can actually move the lever laterally in and out of the gate.  If there were to be any gap here then any vibration in the system could cause the lever to move forward slightly thus partially retracting the undercarriage and bringing the "over-centreness" of the lock to a critical point where it might go past the point of no return and collapse.  If it was to go past that point with the weight of the aircraft on the wheel then nothing will save it!



(b) Furthermore, with the gear down and locked, the amount of over-centre must be checked to be correct.  An accurate method of sighting up (the centres) must be devised.  The middle pivot point (top reaction plate clevis pins) must be min 1/16'' and max 1/8'' forward of the top pivot point (LG8 mounting shaft) and bottom pivot point (LG04 pin).  Too much puts extra strain on the LG frame, too little and the over-centre lock would be critically ''weak'.  To achieve this the LG8 stops must be the correct length.  They ''should'' be correct from manufacture but I have heard of some people having to grind them down a bit and/ or adding to the length to get the amount of over-centre spot on.  Finally the pre-tension of the rubber block must be set correctly to achieve the correct result (79mm between inner faces of the top and bottom reaction plates).



2/ Wear:  Any wear or play anywhere in the system could cause movement which might critically affect the geometry, possibly allowing the over-centre to become critical and collapse.

Namely, wear in any of the pivot points and bushes, wear/ slop developing in the joint between the retraction handle and the port LG8 allowing unwanted movement of the handle relative to the gear (though I notice you have the strut mod so this should have been ok.) etc.



Could it possibly have been that on yours you may have had some gap at the front of the gear handle, or maybe the LG8 stops were slightly too long thus not giving a safe amount of over-centre?  These seem to me to be the most likely causes.



I'm not opening the oft-argued debate about which version of the Europa is best again.  (Monowheel IS the best one!!!!!!)

Good luck and Regards, Jon

_________________
G-TERN
Classic Mono

ken carp

Joined: 31 Oct 2008
Posts: 29
Location: Knoxville, TN

Posted: Fri Jun 10, 2011 11:17 am Post subject: N127ZP Landing gear failure.

Had same event when taxing my plane.  I did not have mod 51.  There is still the issue of the gear needing to be over center.  I am sure someone else can describe it better than I.  My rotax did not have to be torn down but the prop blades had to be replaced and the tunnel repaired.  Mine looked about like yours if that is any consolation.  I hoisted it up by the engine while  doing the underneath repair.



Sent from my iPad



On Jun 3, 2011, at 2:15 PM, "Jeffrey J Paris" <jeffrey-j-paris(at)excite.com> wrote:



 	  Quote: 	
		   Hi Bud,

  

 We had a major problem today, during a taxi and a stationary run-up our landing gear collapsed and nuked our prop and pancaked our airplane onto the tarmac at my local airport.  Needless to say I'm feeling a bit devastated, but I'm very grateful as my Father pointed out ,"that thank god I wasn't taking off or landing when the gear failed."  I had to agree wholeheartedly!  Anyways, any ideas or has anyone else out there suffered the same problem?  During my build I definitely was concerned that the "Gear" handle was doing 3 jobs, deploying/retracting the main gear, flaps and outriggers.  My aircraft has been on the mains since last September and has been moved in and out of the hanger many times, what gives besides the gear?  I have attached some pictures that may shed some light to your experienced eye.  

  

 Looks like a total tear down for the engine?  Mod 51 incorporated. The aircraft is insured, my Father was a successful Insurance Agent and we are covered pending an inspection from claims.

  

 Accident Information regarding N127ZP  Europa Monowheel Classic.

  

 Pilot/Owner: Jeff Paris at controls at time of accident, Phase I of ground testing.

  

 When:  June 3, 2011 approximately 12:30 PM at hanger located SDC  perfect VFR conditions.

  

 Where:  Parked on Taxiway on south side of field 

  

 How and What:  Was test running engine up on taxiway near hanger.  Aircraft was stationary with parking brake engaged.  During engine run-up pilot looked down to close throttle after successful run-up and noticed that the landing gear handle was bent/bending to the left.  Pilot immediately attempted to shut down engine when the gear collapsed and propeller struck the ground and stopped engine.  At time of preflight inspection  and up to accident all safety latches for the landing gear on the aircraft appeared to be functioning and engaged as designed. Aircraft dismantled and stored in owners hanger, pending review of damage.

  

 I guess we all heard the saying there are two types of retractable pilots one that has had a gear up landing and those that will, I didn't expect to have a collapse just sitt ing there monitoring the gauges. . . WTF! 

  

 Thanks for your time and consideration.

  

 Jeff Paris

  

  

 <IMG_2504.jpg>

 <IMG_2505.jpg>

 <IMG_2506.jpg>

 <IMG_2508.jpg>

_________________
ken carpenter

tonywickens(at)btconnect.
Guest

Posted: Fri Jun 10, 2011 1:36 pm Post subject: N127ZP Landing gear failure.

The retraction lever should be taking no load when the u/c is extended but 

merely hold the mechanism in the over centre position. From the pictures it 

would seem that a great load has been put on the retraction lever indicating 

that the mechanism was not in the over centre position when the lever was in 

the down and locked detent. This is something that should be carefully 

checked during set up and during servicing checks. I am very sorry for Jeff 

as it looks a lovely aircraft but it should be quite easy to repair. 

Remember to send me some pictures for the Europa Flyer when she is flying 

again

Regards

Tony



--

grahamsingleton(at)btinte
Guest

Posted: Fri Jun 10, 2011 3:02 pm Post subject: N127ZP Landing gear failure.

There can be a condition when the over centre flicks the other way and becomes under centre. If the airplane bounces the gear then pulls downwards for an instant and if the lock is slightly loose the lever will allow it to flick under centre. When the load comes back on the gear the inevitable collapse occurs.

Graham

From: Tony Wickens <tonywickens(at)btconnect.com>

To: europa-list(at)matronics.com

Sent: Friday, 10 June, 2011 22:33:12

Subject: Re: N127ZP Landing gear failure.

--> Europa-List message posted by: "Tony Wickens" <tonywickens(at)btconnect.com (tonywickens(at)btconnect.com)>

The retraction lever should be taking no load when the u/c is extended but merely hold the mechanism in the over centre position. From the pictures it would seem that a great load has been put on the retraction lever indicating that the mechanism was not in the over centre position when the lever was in the down and locked detent. This is something that should be carefully checked during set up and during servicing checks. I am very sorry for Jeff as it looks a lovely aircraft but it should be quite easy to repair. Remember to send me some pictures for the Europa Flyer when she is flying again

Regards

Tony

--

ward.t(at)xtra.co.nz
Guest

Posted: Fri Jun 10, 2011 4:46 pm Post subject: N127ZP Landing gear failure.

Graham,

Done that! Been there! I did not have the spring on the down latch and somehow the latch flicked up on landing allowing the lever to come out and go forward the way you describe.

Consulting my licensed engineer I only needed to replace props, repair damage to tunnel and wing where one of the props hit. I did not need to do anything with the Rotax 912S as there was no load on the engine at the time. Had to get the airmaster prop hub crack tested. All happened in slow motion! Third flight so very disheartened however the aircraft main wheel and outriggers kept the fuselage off the grass runway preventing further damage. Good design feature!

Tim

Tim Ward12 Waiwetu Street

Fendalton,

Christchurch,

New Zealand.

ward.t(at)xtra.co.nz (ward.t(at)xtra.co.nz)

Ph 64 3 3515166

Mob 0210640221





On 11/06/2011, at 10:58 AM, GRAHAM SINGLETON <grahamsingleton(at)btinternet.com (grahamsingleton(at)btinternet.com)> wrote:



[quote]There can be a condition when the over centre flicks the other way and becomes under centre. If the airplane bounces the gear then pulls downwards for an instant and if the lock is slightly loose the lever will allow it to flick under centre. When the load comes back on the gear the inevitable collapse occurs.

Graham



From: Tony Wickens <tonywickens(at)btconnect.com (tonywickens(at)btconnect.com)>

To: [url=mailto:europa-list(at)matronics.com]europa-list(at)matronics.com (europa-list(at)matronics.com)[/url]

Sent: Friday, 10 June, 2011 22:33:12

Subject: Re: N127ZP Landing gear failure.



--> Europa-List message posted by: "Tony Wickens" <[url=mailto:tonywickens(at)btconnect.com]tonywickens(at)btconnect.com (tonywickens(at)btconnect.com)[/url]>



The retraction lever should be taking no load when the u/c is extended but merely hold the mechanism in the over centre position. From the pictures it would seem that a great load has been put on the retraction lever indicating that the mechanism was not in the over centre position when the lever was in the down and locked detent. This is something that should be carefully checked during set up and during servicing checks. I am very sorry for Jeff as it looks a lovely aircraft but it should be quite easy to repair. Remember to send me some pictures for the Europa Flyer when she is flying again

Regards

Tony



--

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