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Vertical play at stabilator tips

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n7188u

Joined: 15 Nov 2015
Posts: 395

Posted: Sun Sep 30, 2018 4:18 am Post subject: Vertical play at stabilator tips

Dear Forum Members,



I just finished getting everything ready to bond the fuselage top. I spent the last two weeks tweaking the clecoing of the fuselage top (and other nifty simple tricks which I can share) to ensure I had nearly zero friction in the stab torque tube bearings. It is so smooth that now I am able to feel vertical play when I move the stab tip vertically. The play, at the TP11 bearing, is in the order of 0.004 to 0.005 inches. Doesn't sound like much but at the tip of the stab is quite noticeable. This play doesn't make me happy (new plane, sloppy already) but before I start tearing things apart (which I am becoming quite adept at this point) I need to know:



1.- Is there a specification for maximum play between the TP11 bearing and TP12 drive plate?

2.- Anyone knows the tolerances for the diameters of these components (TP11 ID and TP12 OD) so that I can measure them?

3.- Is this play common in airplanes where the builder was able to achieve nearly perfect alignment of these components?



I contacted Europa (first time since I started building) to see what they tell me.



Regards,

Chris Martin

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

Posted: Sun Sep 30, 2018 11:05 am Post subject: Vertical play at stabilator tips

Hi Chris,Look at Mod 62 and 73 on:

http://www.europa-aircraft.com/updates/mods.php

Cheers,

Tim



Tim Ward12 Waiwetu Street,

Fendalton,

Christchurch, 8052

New Zealand

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

Mob +64 210640221





On 1/10/2018, at 1:18 AM, n7188u <chmgarb(at)gmail.com (chmgarb(at)gmail.com)> wrote:

 	  Quote: 	
		  --> Europa-List message posted by: "n7188u" <chmgarb(at)gmail.com (chmgarb(at)gmail.com)>



Dear Forum Members,



I just finished getting everything ready to bond the fuselage top. I spent the last two weeks tweaking the clecoing of the fuselage top (and other nifty simple tricks which I can share) to ensure I had nearly zero friction in the stab torque tube bearings. It is so smooth that now I am able to feel vertical play when I move the stab tip vertically. The play, at the TP11 bearing, is in the order of 0.004 to 0.005 inches. Doesn't sound like much but at the tip of the stab is quite noticeable. This play doesn't make me happy (new plane, sloppy already) but before I start tearing things apart (which I am becoming quite adept at this point) I need to know:



1.- Is there a specification for maximum play between the TP11 bearing and TP12 drive plate?

2.- Anyone knows the tolerances for the diameters of these components (TP11 ID and TP12 OD) so that I can measure them?

3.- Is this play common in airplanes where the builder was able to achieve nearly perfect alignment of these components?



I contacted Europa (first time since I started building) to see what they tell me.



Regards,

Chris Martin





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=483466#483466



<==========================;        - The Europa-List Email Fors.com/Navigator?Europa-List">http://www.matronics.com/Navigator?Europa-List<=====================================================================================================;       - NEW MATRONICS LIST WIKI -http://www.matronics.com/contribution<==========================================

JonathanMilbank

Joined: 14 Apr 2012
Posts: 384
Location: Aberdeen area

Posted: Sun Sep 30, 2018 12:08 pm Post subject: Re: Vertical play at stabilator tips

At the risk of being shot down in flames (yet again), this is a subject which is quite dear to my heart. I've asked a few people over the years the same question and never been given a definitive answer. I doubt very much that there's anyone at Europa who could either. What I do know is that the late Nev Eyre replaced the bronze bushes for at least one of his customers, but seemingly only because they wanted it done and not because he thought it was really necessary. That's the impression he gave me anyway.



Either you belong to the school of opinion that even slight play is unacceptable, or you take the pragmatic view of considering whether the play is likely to cause a problem. I fall in with the latter and have no reason to believe that even a mm of play in the bush would cause flutter or any other undesirable effect. One of my bushes has about .010" of movement and the other is probably double that. The airframe has around 1200 hours and I've been aware of play for several years.



In order to keep those bushes lubricated, I have a plastic syringe drilled out to accept a very thin plastic tube of the type which inserts into the nozzle of an ACF 50 spray can. I load the syringe with a little clean engine oil and using a torch, I insert the tube through the narrow gap at the root of each tail plane, either tilting the tail plane forward or backward to facilitate access. The oil flows around and down the metal sleeve which passes through each bush and then wicks sideways into the gaps. A little rocking and sideways movement (if available) of the tail surfaces helps with oil penetration.



This I do every few flying hours and it avoids the need to unpin and slide each tail plane sideways. For the past couple of years there has been no discernible increase in wear of the bushes.

Last edited by JonathanMilbank on Mon Oct 01, 2018 10:19 am; edited 1 time in total

n7188u

Joined: 15 Nov 2015
Posts: 395

Posted: Sun Sep 30, 2018 2:36 pm Post subject: Re: Vertical play at stabilator tips

Thanks so much both Tim and Jonathan for the replies. I am glued to the computer awaiting feedback  . Tim: maybe I was not clear but the issue is with play between the bronze (or brass) bushings and the torque tube. I do have the clamp mod so the torsion between the two tailplanes is free of slop. Also have the 3/8 pins plus the mod 10672 (glass tube). The elongated pip-pin hole will be implemented before finishing the plane.



Jonathan, your comment about the play makes me feel a little better. What is hard for an isolated builder like me is that I have no reference as to what is OK or not. No play is probably unrealistic in a system like this that is impossible to adjust or replace bushings easily. I also imagine that, as hard as Europa may try, achieving tight tolerances on that machined and welded TP12 drive plate tube is probably very difficult. and if they did make tolerances tight, I am not sure you could assemble it as the manual tells you to do it and not end up with binding in the system. I love my Europa, but I do tell my friends this is like building a very precise blob of flexible epoxy/glass. You can only be so precise! My opinion.



My bushings are indeed much better than 0.015". Was that at the bushing itself or the tip of the stabilator?  My 0.005" is at the bushing. I calculated the tip would move about 0.020" with that play at the bushing but its hard to measure at the tip since everything moves when you put some force to it.



Anyway, please keep the advise coming. I did ask Europa to see what they say. Ultimately, I would love to know what the tolerances for these components are when they are manufactured. That way I could measure and decide to go or not go. Everything in life must have tolerances and some amount of design factor to account for wear.



Just a story regarding opinions: I had an older Mooney that had slop in the elevator trim system (the trim moves the entire tail in the Mooney, really, the whole tail including the vertical fin). Some people would scream at me that the play was unacceptable even though it meet the maintenance manual criteria. I flew the plane like that for 13 years with no issue. The only thing that makes it hard now is that the top is not bonded yet so it would be relatively easy to replace the bushing. But if I don't have to I prefer to save myself unnecessary work. Heck, I don't even know if the new bushing would be any better because I don't know the tolerances or limits.



Best Regards,

Chris

budyerly(at)msn.com
Guest

Posted: Sun Sep 30, 2018 2:53 pm Post subject: Vertical play at stabilator tips

Jon, 

I have replaced these where the client felt they were too stiff and either put polishing compound on them or actually machined them larger.   

  

As far as slop, a slight clunk of the stab up and down, for and aft won’t hurt anything especially if it a small .005 inch play. 

Force in some grease rather than oil if you can’t stand the noise.  Pack the grease in using your fingers and a lot of pressure normally once a year and it will be fine. 

  

To replace them just requires disassembly of the tail plane torque tube.  (I hope you made your inspection hole larger.)  I have had to pull a couple of them out, an 8 hour day is normal.  One had only the sight hole to inspect, I put  a six inch hole in the back to get my arm in there and patched the fuselage.  It was the only way to stay sane. 

  

Bud Yerly 

Custom Flight Creations 

  

Sent from  Mail for Windows 10 

  

  From: owner-europa-list-server(at)matronics.com <owner-europa-list-server(at)matronics.com> on behalf of JonathanMilbank <jdmilbank(at)yahoo.co.uk>

 Sent: Sunday, September 30, 2018 4:08:47 PM

 To: europa-list(at)matronics.com

 Subject: Re: Vertical play at stabilator tips  

 

 

  --> Europa-List message posted by: "JonathanMilbank" <jdmilbank(at)yahoo.co.uk>

 

 At the risk of being shot down in flames (yet again), this is a subject which is quite dear to my heart. I've asked a few people over the years the same question and never been given a definitive answer. I doubt very much that there's anyone at Europa who could  either. What I do know is that the late Nev Eyre replaced the bronze bushes for at least one of his customers, but seemingly only because they wanted it done and not because he thought it was really necessary. That's the impression he gave me anyway.

 

 Either you belong to the school of opinion that even slight play is unacceptable, or you take the pragmatic view of considering whether the play is likely to cause a problem. I fall in with the latter and have no reason to believe that even a mm of play in  the bush would cause flutter or any other undesirable effect. One of my bushes has about .015" of movement and the other is probably double that. The airframe has around 1200 hours and I've been aware of play for several years.

 

 In order to keep those bushes lubricated, I have a plastic syringe drilled out to accept a very thin plastic tube of the type which inserts into the nozzle of an ACF 50 spray can. I load the syringe with a little clean engine oil and using a torch, I insert  the tube through the narrow gap at the root of each tail plane. The oil flows around and down the metal sleeve which passes through each bush and then wicks sideways into the gap.

 

 This I do every few flying hours and it avoids the need to unpin and slide each tail plane sideways. For the past couple of years there has been no discernible increase in wear of the bushes.

 

 

 

 

 Read this topic online here:

 

 https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fforums.matronics.com%2Fviewtopic.php%3Fp%3D483481%23483481&amp;data=02%7C01%7C%7C2cdd49b7a6654b0af71908d62710ff86%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636739351280999107&amp;sdata=dwZcI28X1tMBia2mAZdtdU8a9WEuECUyVX2OQDxQ0U8%3D&amp;reserved=0

 

 

 

 

 

 

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kingsnjan(at)westnet.com.
Guest

Posted: Sun Sep 30, 2018 4:32 pm Post subject: Vertical play at stabilator tips

Chris



<  It is so smooth that now I am able    to feel vertical play when I move the stab tip vertically. 



I wouldnâ€™t be concerned if I were you ..... mine is exactly the same.  Congratulate yourself on having the bushes perfectly aligned. If you had no movement at all, it would mean the bushes were not properly aligned and the torque tube would be resting on high spots. 



The same situation arises with the main wing pin bushes. They are quite a loose fit on the main pins so if the pins are tight, it simply means the bushes are not perfectly aligned. 



Put the top on and move on mate!



Kingsley in Oz

n7188u

Joined: 15 Nov 2015
Posts: 395

Posted: Mon Oct 01, 2018 2:51 am Post subject: Re: Vertical play at stabilator tips

 Once again thanks to all for the advice. It is in moments like this during the construction of a kit plane that the support and encouragement from fellow builders is so important. I will move forward as is.



To me, I deem smooth elevator control as a very important feature to achieving good landings in an airplane. When I had my Mooney (another airplane with not so great landing reputation [I'm building a mono]) the key to smooth landings was smooth elevator control. I dissasembled the entire pushrod system in that airplane (quite complex but neat) and rebuilt it to achieve smooth control and great landings every time ensued. 



It was an interesting learning experience to achieve this in the Europa. I understood the fuselage was flexible but I got down to a point where just adding one cleco could result in noticing binding (very slight). Probably not that critical but I was that picky. I ended up designing two small ribs. One behind the aft bulkhead, about the height where the bearings are located and about 1.5" wide and another at the bonding flange location between the aft bulkhead and the sternpost, the latter helping maintain the curve that was present when the bearings where initially installed. Plus reinforcing the forward stick used to set the aft bottom fuselage spread when installing the bearing. This stiffened the entire aft section enough to prevent the bearings from twisting and binding when the top is clecoed in place. The other thing was to leave some clecoes out of the flange where the fin skin attaches to the bottom since some clecos here could cause binding and let its natural curvature set its shape. in fact, very similar to what I had to do to the cockpit module to keep controls from becoming stiff.



If I was doing this again, I would NOT follow the manual instructions again when installing the torque tube. I would instead set the entire fuselage with clecos (as recommended by the clamp mod instructions) and, at the last moment, I would bond the bearings even if it was a difficult task. Bud Yearly also provided advice about using stronger sticks to hold the bottom fuselage shape back there, which is what I tried to achieve with the ribs after the fact. I really concur with that advice since any miniscule deformation affected the bearings back there.



My recommendation to Europa is to really rethink how controls are installed in this build for future kits sold. Although the current cockpit module and top bonding installs are geared toward ease of build, I don't think it works well to keep controls smooth. The fuselage really needs to be much stiffer before controls are set permanently.



Anyway, many thanks to all and looking forward to my friends stop calling my project "The Canoe Build" 



Best Regards,

Chris

peterz(at)zutrasoft.com
Guest

Posted: Mon Oct 01, 2018 3:57 am Post subject: Vertical play at stabilator tips

Great post Chris, thx!

I have made a steel frame build cradle for my canoe, so I am hoping the alignment will not change enough with top-bonding to cause binding issues. That said I was also planning on stabilizing the cockpit module prior to bonding to minimize binding, so I am intrigued by your re-enforcing strategy which I don't fully follow/understand. Could you send me some pics?

Cheers and thx,



Pete

On Mon, Oct 1, 2018 at 6:58 AM n7188u <chmgarb(at)gmail.com (chmgarb(at)gmail.com)> wrote:



 	  Quote: 	
		  --> Europa-List message posted by: "n7188u" <chmgarb(at)gmail.com (chmgarb(at)gmail.com)>

 

  Once again thanks to all for the advice. It is in moments like this during the construction of a kit plane that the support and encouragement from fellow builders is so important. I will move forward as is.

 

 To me, I deem smooth elevator control as a very important feature to achieving good landings in an airplane. When I had my Mooney (another airplane with not so great landing reputation [I'm building a mono]) the key to smooth landings was smooth elevator control. I dissasembled the entire pushrod system in that airplane (quite complex but neat) and rebuilt it to achieve smooth control and great landings every time ensued. 

 

 It was an interesting learning experience to achieve this in the Europa. I understood the fuselage was flexible but I got down to a point where just adding one cleco could result in noticing binding (very slight). Probably not that critical but I was that picky. I ended up designing two small ribs. One behind the aft bulkhead, about the height where the bearings are located and about 1.5" wide and another at the bonding flange location between the aft bulkhead and the sternpost. Plus reinforcing the forward stick used to set the aft bottom fuselage spread when installing the bearing. This stiffened the entire aft section enough to prevent the bearings from twisting and binding when the top is clecoed in place.

 

 If I was doing this again, I would NOT follow the manual instructions again when installing the torque tube. I would instead set the entire fuselage with clecos (as recommended by the clamp mod instructions) and, at the last moment, if would bond the bearings even if it was a difficult task. Bud Yearly also provided advice about using stronger sticks to hold the bottom fuselage shape back there, which is what I tried to achieve with the ribs after the fact. I really concur with that advice since any miniscule deformation affected the bearings back there.

 

 Anyway, many thanks to all and looking forward to my friends stop calling my project "The Canoe Build" 

 

 Best Regards,

 Chris

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=483494#483494

 

 

 

 

 

 

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tennant

Joined: 19 Apr 2011
Posts: 121

Posted: Mon Oct 01, 2018 4:07 am Post subject: Re: Vertical play at stabilator tips

Hi Chris,



Be glad that you have an elevator without stiffness. At fly inn's I have felt stiffness in other Europa elevators. This must be quite annoying when trying to trim.

Mine is quite free with a little play.



Barry

_________________
Barry Tennant
D-EHBT
At EDLM - Germany

n7188u

Joined: 15 Nov 2015
Posts: 395

Posted: Mon Oct 01, 2018 11:27 am Post subject: Re: Vertical play at stabilator tips

I will be delighted to share what I did. Just give me a little time because I work far from home and by the time I get there I work on the plane and then I am too pooped to sit in front of a computer. I will send bits of info and pictures here and there. enough to keep the conversation fun 



So that we are clear on the kind of feedback I can give:



1.- I am not an expert Europa builder so whatever I do may or may not work. Seems to be working for me though. Also, I am in the USA so anything I show here may not be possible in Europe. However, the concepts still apply.



2.- I am a Mechanical Design Engineer, Aviation Mechanic, built a Cozy mark IV and worked for an Aviation Structural Engineering firm at one point in my life. Not to rub it just so that you know I am not totally insane when I try to do a change (although I never claimed I donâ€™t make mistakes ). And I do know there are probably better ways to do things. Also, as Burt Rutan used to say, if you modify it, you are now the designer and the test pilot of a brand airplane design!



3.- Rule number one: donâ€™t force or bend anything into place, just let stuff find its happy relaxed state and then attach. Simple concept, hard to implement. If you have to bend or force anything then check its effect on the control system.



The issue I see with the control system assembly in the Europa has to do, in my opinion, with how flexible everything is in these planes. I discovered the hard way that when you install the controls in the cockpit module and the aft part of the fuselage, any miniscule strain placed in the CM or fuselage bottom afterward will cause small distortions that will increase friction in the system. I'm not kidding, I spent hours, by inserting one cleco at a time and checking friction, to find which clecos would increase friction in the controls (and which would reduce it). I would then leave that cleco out and fill the small gap with a little extra epoxy. If the gap is large then thatâ€™s a story for another lengthy writing.



With that said, I found that to achieve smooth controls is to avoid component distortion. And a cleco distorts too much in this plane! And so why am convinced that the right way to do this would be to bond the CM in the fuselage, cleco the top perfectly and then bond all the control bearings in place. Maybe impossible to do but would be ideal.



BTW, I may still end up with stiff controls since I have no idea if anything later on will cause stuff to strain and bind the controls. Probably yes. But my hope is that my effort will minimize the binding. Right now, a light breeze will move the stabilators and I am happy! Letâ€™s see if I can keep it that way!



BTW, and I learned this from Bud Yerly, beware of cradles that fixate the fuselage too much. If you build like that and then remove the cradle things will go where they want to go and thus create binding. This thing is like a gigantic bunch of springs that are tied to each other. If you constrain them and then relax them, they will find a balance and it may not be where you want it. I do have a cradle but nothing touches the fuselage except a small â€œtableâ€ at the bottom of the forward fuselage in the CM area and thatâ€™s it. I screwed the fuselage to this table through the CM flanges to keep the bottom flat and level. Essentially what the manual tells you to do but instead of a bunch of pallets I have a nifty table on wheels. Then I still have the advantage of a cradle with minimal distortion to the fuselage. Again, donâ€™t know if any of this will bite me in the you know what later on but that is how I am doing it. Oh, wait, did I said I screwed the fuselage to the table, oh boy, letâ€™s see what happens when I let go, or put it on the gear, or hang the engine or sit on it, etc, etc, etc 



Pictures and explanations will follow on all this I talked about.

n7188u

Joined: 15 Nov 2015
Posts: 395

Posted: Mon Oct 01, 2018 12:30 pm Post subject: Re: Vertical play at stabilator tips

BTW Barry, I am jealous that you have a smooth system AND no play. 



Not happy about the play but advice was received, consideration given and decision made.



Another goal of mine is to finish this plane before my son goes to college so I am in production mode! It seems that although not easy, the bushings can be changed at a later date so it's not the end of the world if I get tired of the play. Another consideration is that I may need that additional clearance if things flex a little later in the build so it will stay as is for now.



Chris

DuaneFamly(at)aol.com
Guest

Posted: Mon Oct 01, 2018 3:03 pm Post subject: Vertical play at stabilator tips

Just for fun sake..... where in the States are you?

Mike Duane

Europa XS Conventional Gear

Las Vegas, NV



Sent from my iPhone



 	  Quote: 	
		   On Oct 1, 2018, at 12:27 PM, n7188u <chmgarb(at)gmail.com> wrote:

 

 

 

 I will be delighted to share what I did. Just give me a little time because I work far from home and by the time I get there I work on the plane and then I am too pooped to sit in front of a computer. I will send bits of info and pictures here and there. enough to keep the conversation fun 

 

 So that we are clear on the kind of feedback I can give:

 

 1.- I am not an expert Europa builder so whatever I do may or may not work. Seems to be working for me though. Also, I am in the USA so anything I show here may not be possible in Europe. However, the concepts still apply.

 

 2.- I am a Mechanical Design Engineer, Aviation Mechanic, built a Cozy mark IV and worked for an Aviation Structural Engineering firm at one point in my life. Not to rub it just so that you know I am not totally insane when I try to do a change (although I never claimed I donâ€™t make mistakes ). And I do know there are probably better ways to do things. Also, as Burt Rutan used to say, if you modify it, you are now the designer and the test pilot of a brand airplane design!

 

 3.- Rule number one: donâ€™t force or bend anything into place, just let stuff find its happy relaxed state and then attach. Simple concept, hard to implement. If you have to bend or force anything then check its effect on the control system.

 

 The issue I see with the control system assembly in the Europa has to do, in my opinion, with how flexible everything is in these planes. I discovered the hard way that when you install the controls in the cockpit module and the aft part of the fuselage, any miniscule strain placed in the CM or fuselage bottom afterward will cause small distortions that will increase friction in the system. I'm not kidding, I spent hours, by inserting one cleco at a time and checking friction, to find which clecos would increase friction in the controls (and which would reduce it). I would then leave that cleco out and fill the small gap with a little extra epoxy. If the gap is large then thatâ€™s a story for another lengthy writing.

 

 With that said, I found that to achieve smooth controls is to avoid component distortion. And a cleco distorts too much in this plane! And so why am convinced that the right way to do this would be to bond the CM in the fuselage, cleco the top perfectly and then bond all the control bearings in place. Maybe impossible to do but would be ideal.

 

 BTW, I may still end up with stiff controls since I have no idea if anything later on will cause stuff to strain and bind the controls. Probably yes. But my hope is that my effort will minimize the binding. Right now, a light breeze will move the stabilators and I am happy! Letâ€™s see if I can keep it that way!

 

 BTW, and I learned this from Bud Yearly, beware of cradles that fixate the fuselage too much. If you build like that and then remove the cradle things will go where they want to go and thus create binding. This thing is like a gigantic bunch of springs that are tied to each other. If you constrain them and then relax them, they will find a balance and it may not be where you want it. I do have a cradle but nothing touches the fuselage except a small â€œtableâ€ at the bottom of the forward fuselage in the CM area and thatâ€™s it. I screwed the fuselage to this table through the CM flanges to keep the bottom flat and level. Essentially what the manual tells you to do but instead of a bunch of pallets I have a nifty table on wheels. Then I still have the advantage of a cradle with minimal distortion to the fuselage. Again, donâ€™t know if any of this will bite me in the you know what later on but that is how I am doing it. Oh, wait, did I said I screwed the fuselage to the tab!

 le, oh boy, letâ€™s see what happens when I let go, or put it on the gear, or hang the engine or sit on it, etc, etc, etc 

 

 Pictures and explanations will follow on all this I talked about.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=483511#483511

n7188u

Joined: 15 Nov 2015
Posts: 395

Posted: Mon Oct 01, 2018 5:14 pm Post subject: Re: Vertical play at stabilator tips

Hi Mike,



Daytona, Florida. I'm actually not that isolated. There are two Europas in the field but, as much as I try to connect with the owners or get a ride in one, it never happens (one is two hangars from mine so it can't get any closer). Maybe one day I will be able to ride one, hopefully before mine flies 



So here are some pictures I just posted in my build site:



https://sites.google.com/site/martineuropaxsa291/Fuselage



The stiffening ribs behind the aft bulkhead is just an ugly attempt at preventing binding of the stab bearings. It's working well though not very elegant. As mentioned, next time around (yeah right) I will cleco the fuselage before bonding the bearings (or some other nifty way).



I thought I had a good picture posted of the cradle I have (built by the builder I got the kit from) but its not there. There are a couple of pictures of the cradle but you can't see the flat surface under the fuselage which is where the fuselage is actually resting. The cradle fuselage supports (or whatever those rib things are called) are not touching the fuselage. I trim those back so that there is about an inch of clearance all around between the supports and the fuselage skin. This was done to keep the cradle from deforming the fuselage in any way. Those supports (or ribs) are still there so that I can tilt the whole cradle and still support the fuselage. I also plan to remove the flat surface when ready to install the gear.



Enjoy perusing my site and if you see anything I did wrong let me know 



Chris

Duncan McFadyean

Joined: 18 Jan 2011
Posts: 218

Posted: Tue Oct 02, 2018 8:32 am Post subject: Vertical play at stabilator tips

...<<if you see anything I did wrong let me know >>

Re. Stiffener rib behind aft bulkhead at bonding flange level:

I incorporated similary, slightly longer for-aft. It greatly stabilised the lower fus during construction resulting in well aligned TP bearings. In early flights, hairline cracking appeared in the paint film on the outer skin at the location of the web. So I cut out the web and the hairline cracks have progressed no further. 

Duncan McF.

 

 ----Original Message----

From: chmgarb(at)gmail.com

Date: 02/10/2018 02:14

To: <europa-list(at)matronics.com>

Subj: Re: Vertical play at stabilator tips



--> Europa-List message posted by: "n7188u" <chmgarb(at)gmail.com>



Hi Mike,



Daytona, Florida. I'm actually not that isolated. There are two Europas in the field but, as much as I try to connect with the owners or get a ride in one, it never happens (one is two hangars from mine so it can't get any closer). Maybe one day I will be able to ride one, hopefully before mine flies 



So here are some pictures I just posted in my build site:



https://sites.google.com/site/martineuropaxsa291/Fuselage



The stiffening ribs behind the aft bulkhead is just an ugly attempt at preventing binding of the stab bearings. It's working well though not very elegant. As mentioned, next time around (yeah right) I will cleco the fuselage before bonding the bearings (or some other nifty way).



I thought I had a good picture posted of the cradle I have (built by the builder I got the kit from) but its not there. There are a couple of pictures of the cradle but you can't see the flat surface under the fuselage which is where the fuselage is actually resting. The cradle fuselage supports (or whatever those rib things are called) are not touching the fuselage. I trim those back so that there is about an inch of clearance all around between the supports and the fuselage skin. This was done to keep the cradle from deforming the fuselage in any way. Those supports (or ribs) are still there so that I can tilt the whole cradle and still support the fuselage. I also plan to remove the flat surface when ready to install the gear.



Enjoy perusing my site and if you see anything I did wrong let me know 



Chris





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=48351=          - The Europa-List            &nbbsp;                        &n===================

Duncan McFadyean

Joined: 18 Jan 2011
Posts: 218

Posted: Tue Oct 02, 2018 8:33 am Post subject: Vertical play at stabilator tips

..<<Congratulate yourself on having the bushes perfectly aligned.>>

And my inspector thinks the slight radial play on well aligned TP bearings is TP pin play! It's not.

At annual innspection I now add some thickish oil to the TP bearings, which masks the bearing play and removes the argument.

Duncan McF

 

 ----Original Message----

From: kingsnjan(at)westnet.com.au

Date: 01/10/2018 01:32

To: <europa-list(at)matronics.com>

Subj: Re: Europa-List: Vertical play at stabilator tips



--> Europa-List message posted by: Kingsley Hurst <kingsnjan(at)westnet.com.au>



Chris



<  It is so smooth that now I am able    to feel vertical play when I move the stab tip vertically. 



I wouldnâ€™t be concerned if I were you ..... mine is exactly the same.  Congratulate yourself on having the bushes perfectly aligned. If you had no movement at all, it would mean the bushes were not properly aligned and the torque tube would be resting on high spots. 



The same situation arises with the main wing pin bushes. They are quite a loose fit on the main pins so if the pins are tight, it simply means the bushes are not perfectly aligned. 



Put the top on and move on mate!



Kingsley in Oz

n7188u

Joined: 15 Nov 2015
Posts: 395

Posted: Tue Oct 02, 2018 10:57 am Post subject: Re: Vertical play at stabilator tips

Duncan, interesting info on the experience you had with the stiffening member behind the bulkhead as I did. True that there could be a bit of point load on the skin from this rib and cause, as in your case, paint to crack. Mine is mounted on a flange glassed to the side skin so maybe I won't have those cracking issues. The top one though is just floxed near the bond flange so it could cause a little strain and cracking of paint at the bond line. Time will tell.



I have mixed feelings about these two ribs. I hate complicating things and adding weight (although in this case not too much). But they do seem to work by keeping the skins that hold the bearings from flexing. It's amazing how little it takes to move those bearings.



Chris

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