Today's Message Index:
----------------------
1. 02:48 AM - undercarriage retraction problem (Rowland Carson)
2. 04:02 AM - Re: undercarriage retraction problem (jonathanmilbank)
3. 05:09 AM - Re: Re: undercarriage retraction problem (Rowland Carson)
4. 05:30 AM - Re: undercarriage retraction problem (jonathanmilbank)
5. 05:39 AM - Re: Re: undercarriage retraction problem (Rowland Carson)
6. 07:58 AM - Re: undercarriage retraction problem (JonSmith)
7. 09:51 AM - Re: Re: undercarriage retraction problem (alan.twigg775@gmail.com)
8. 11:22 AM - Re: undercarriage retraction problem (JonSmith)
9. 05:38 PM - Re: undercarriage retraction problem (Keith Hickling)
10. 10:14 PM - Re: undercarriage retraction problem (JonSmith)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | undercarriage retraction problem |
Ive finally managed to satisfy myself that the flaps are operating over the correct
range, and moved on to installing the undercarriage. After fitting the LG02
swinging arm to the LG01 mounting frame, I was still (just) able to operate
the retract lever without any bungee assistance. Then I fitted the wheel and
brake to LG02 and of course that made it too heavy to retract without the bungee.
Yesterday I fitted the bungee and was pleased to find a number of loops and tension
that nicely balanced the weight of the undercarriage and allowed the lever
to operate quite easily. However, I couldnt quite get the lever into the up
gate. Examination of everything showed that (1) the tyre was hitting the brake
master cylinder and its elbow connexion and (2) the brake slave cylinder was
catching the rudder cable.
Initially it looked as if LG02 might be too far to starboard, but I had taken care
when fixing LG01 into the fuselage to have LG02 temporarily fitted, and inserted
packing to keep LG02 equidistant from the tunnel at each side.
The other possibility that occurred to me was that (despite careful measurements
against the manual callout) Id pre-compressed the LG06 suspension block at bit
too much, causing the distance between the LG08 pivots and the LG02 pivots
to be too small, thus making the LG02 swinging arm retract too far.
I tried backing off the M8 stiffnuts a little (which involved removing and re-installing
the bungee again - nobody mentioned how hard it is to thread the bungee
around LG02B anchor tube) and that did seem to allow a little but more movement
in the up direction but nowhere near enough to get the lever into the up
gate. While looking at everything after that adjustment, it seems that the linkage
is not quite going over-centre in the down position - it appears the 3 pivots
are just about in line with each other. I wonder if lengthening the suspension
assembly has caused that.
Can anyone suggest what I might be doing wrong, please, or any way to solve the
problem?
in friendship
Rowland
| Rowland Carson ... that's Rowland with a 'w' ...
| <rowlandcarson@gmail.com> http://www.rowlandcarson.org.uk
| Skype, Twitter: rowland_carson Facebook: Rowland Carson
| pictures: http://picasaweb.google.com/rowlandcarson
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: undercarriage retraction problem |
Hi Rowland. First let me state that I did all this construction stuff 20 years
ago and that my aircraft was converted to tri-gear in November 2012, so it was
operated as a mono for over 850 hours. Anyway, if memory serves me correctly
the LG06 suspension block was hardly compressed at all before installation and
only when the full weight of the aircraft was resting on the wheel, did the block
become compressed. Thus if you were to reach up into the wheel bay while
lying under your aircraft, you would find that the two bolts passing vertically
through the block would be loose i.e. have a few millimetres sliding end play.
Obviously this would suggest that the suspension block was not in compression while
the wheel was retracted. It worked happily like this for about 17 years.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=443126#443126
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: undercarriage retraction problem |
On 6 Jun 2015, at 12:01, jonathanmilbank <jdmilbank@yahoo.co.uk> wrote:
> if memory serves me correctly the LG06 suspension block was hardly compressed
at all before installation and only when the full weight of the aircraft was
resting on the wheel, did the block become compressed. Thus if you were to reach
up into the wheel bay while lying under your aircraft, you would find that
the two bolts passing vertically through the block would be loose i.e. have a
few millimetres sliding end play.
Jonathan - thanks for your message. Id be happy to try the effect of further loosening
the M8 bolts that hold the suspension assembly together, but after my
first loosening there is now is barely enough thread protruding beyond the nuts
to keep them in safety, so theres not much room for further experiment.
I can believe that the weight of the aircraft will compress LG06 quite a bit and
thus leave the bolts loose, but on initial assembly I found I had to use G-clamps
to compress the thing enough to even get the nuts started on the threads.
in friendship
Rowland
| Rowland Carson ... that's Rowland with a 'w' ...
| <rowlandcarson@gmail.com> http://www.rowlandcarson.org.uk
| Skype, Twitter: rowland_carson Facebook: Rowland Carson
| pictures: http://picasaweb.google.com/rowlandcarson
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: undercarriage retraction problem |
Your suspension block is probably different from mine, which was one of the earliest
and came needing work done by the builder. It was red in colour, solid and
thus needed holes bored through with a hole saw in a drill press. A band saw
was needed to cut out 'V' wedges top and bottom and finally the factory decided
that the block wasn't thick enough, so we had to add in a shim made from a
piece of 1/4" ply board.
Therefore I guess that it's unsurprising that your problems are different. Still,
you might have been in possession of one of the early blocks if you had bought
an old kit from someone.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=443129#443129
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: undercarriage retraction problem |
On 6 Jun 2015, at 13:29, jonathanmilbank <jdmilbank@yahoo.co.uk> wrote:
> Your suspension block is probably different from mine, which was one of the earliest
and came needing work done by the builder. It was red in colour, solid
and thus needed holes bored through with a hole saw in a drill press. A band
saw was needed to cut out 'V' wedges top and bottom and finally the factory decided
that the block wasn't thick enough, so we had to add in a shim made from
a piece of 1/4" ply board.
> Therefore I guess that it's unsurprising that your problems are different. Still,
you might have been in possession of one of the early blocks if you had bought
an old kit from someone.
Jonathan - no, my block is of the newer sort, black with the hole and the notches
already cut out. Anyway, I suspect that the solution to my problem may lie
elsewhere so I dont want to focus on one thing to the detriment of the big picture!
in friendship
Rowland
| Rowland Carson ... that's Rowland with a 'w' ...
| <rowlandcarson@gmail.com> http://www.rowlandcarson.org.uk
| Skype, Twitter: rowland_carson Facebook: Rowland Carson
| pictures: http://picasaweb.google.com/rowlandcarson
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: undercarriage retraction problem |
Hi Rowland,
I remember that the rubber block should be (pre) compressed such that the distance
between the inside faces of the upper and lower reaction plates is 79mm. I
believe that this measurement is critically important and that it would be a
big mistake to differ from that. (Older manuals referred to different points
to measure from, bolt centres etc giving different distances but the end result
was the same).
I also remember reading that the most important part of the correct geometry regarding
the over centre locking is the length of the retraction stops. They should
have been manufactured in the factory such that they were correct but I've
heard they were not always so, so perhaps they are worth checking? When it's
all set up correctly both retraction arms should touch their respective stops
simultaneously and the retraction arms should be parallel with each other.
The geometry of the three bolt centres should also be correcting as per the manual,
ie the centre of the middle pivot (top bolt of the rubber block assembly)
should be 1/16 to 1/8" forward of the line between the other two centres. This
can all be checked and confirmed to be correct with the plane hoisted up and
is easier with the wheel removed.
If the above is all correct then I guess you will have to look elsewhere for your
problem and I don't really know what the answer might be? Can the rudder cables/
fairleads be raised slightly? Can the brake master cylinder be repositioned
slightly?
Good luck! Below is a link to the FSB which gives details of the mandatory undercarriage
checks just in case you haven't seen it - it is on the Europa Club
site.
http://www.theeuropaclub.org/wp-content/uploads/2012/02/FSB004.pdf
--------
G-TERN
Classic Mono
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=443133#443133
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: undercarriage retraction problem |
Rowland, you are welcome to pop over to Bicester, my undercarriage works well and
the aircraft is up on a trestle.
Alan Twigg
Sent from my iPhone
> On 6 Jun 2015, at 13:38, Rowland Carson <rowlandcarson@gmail.com> wrote:
>
>
>> On 6 Jun 2015, at 13:29, jonathanmilbank <jdmilbank@yahoo.co.uk> wrote:
>>
>> Your suspension block is probably different from mine, which was one of the
earliest and came needing work done by the builder. It was red in colour, solid
and thus needed holes bored through with a hole saw in a drill press. A band
saw was needed to cut out 'V' wedges top and bottom and finally the factory decided
that the block wasn't thick enough, so we had to add in a shim made from
a piece of 1/4" ply board.
>> Therefore I guess that it's unsurprising that your problems are different. Still,
you might have been in possession of one of the early blocks if you had
bought an old kit from someone.
>
> Jonathan - no, my block is of the newer sort, black with the hole and the notches
already cut out. Anyway, I suspect that the solution to my problem may lie
elsewhere so I dont want to focus on one thing to the detriment of the big picture!
>
> in friendship
>
> Rowland
>
>
>
>
>
>
>
Message 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: undercarriage retraction problem |
Rowland, just a further thought, you haven't set it up so that it's trying to retract
the wheel too far/ too high? Whereas the undercarriage downlock gate and
set up IS critical I don't think the exact position of the undercarriage lever
UP lock gate is quite so important. Obviously you want it up as much as possible
and not too low but it can't of course go up too far. Adjusting the rear
latching face of the upgate rearwards slightly would mean the wheel wouldn't
lock up quite as far but it might then not foul the items you mentioned. You
would then have to completely re-set up the flap retraction adjustment again
with probably a new flap retraction horn etc....!
Maybe looking at Ian's plane as he mentioned above would give you a very good comparison.
Cheers,
--------
G-TERN
Classic Mono
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=443140#443140
Message 9
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: undercarriage retraction problem |
Rowland,
1) I can't remember why, but I also ended up with the wheel contacting the
brake master cylinder and a rudder cable. I had to move one of the rudder
cable guides slightly, and as jon suggested I had to file back the up gate
slightly so the swing arm did not retract quite so far. As jon said, that
meant having to readjust the flap mechanism.
2) The geometry is complex, but as jon said I think the amount of
precompression of the rubber block is critical to getting the correct amount
of overcentre with the gear down, so the measurement specified in the manual
is important. Ron Parigoris has written a couple of nice emails on the list
concerning the geometry and the fact that on some u/c frames one or both of
the stops were not the correct length and needed filing back a little to
achieve the overcentre position. I seem to recall that there have been a
couple of expensive u/c collapses associated with inadequate overcentre or
slight undercentre positioning. The down gate is not strong enough to hold
the gear down if it is not overcentred against the stops.
Good luck !
Regards,
Keith.
-----Original Message-----
From: Rowland Carson
Sent: Saturday, June 06, 2015 9:47 PM
Subject: Europa-List: undercarriage retraction problem
Ive finally managed to satisfy myself that the flaps are operating over the
correct range, and moved on to installing the undercarriage. After fitting
the LG02 swinging arm to the LG01 mounting frame, I was still (just) able to
operate the retract lever without any bungee assistance. Then I fitted the
wheel and brake to LG02 and of course that made it too heavy to retract
without the bungee.
Yesterday I fitted the bungee and was pleased to find a number of loops and
tension that nicely balanced the weight of the undercarriage and allowed the
lever to operate quite easily. However, I couldnt quite get the lever into
the up gate. Examination of everything showed that (1) the tyre was
hitting the brake master cylinder and its elbow connexion and (2) the brake
slave cylinder was catching the rudder cable.
Initially it looked as if LG02 might be too far to starboard, but I had
taken care when fixing LG01 into the fuselage to have LG02 temporarily
fitted, and inserted packing to keep LG02 equidistant from the tunnel at
each side.
The other possibility that occurred to me was that (despite careful
measurements against the manual callout) Id pre-compressed the LG06
suspension block at bit too much, causing the distance between the LG08
pivots and the LG02 pivots to be too small, thus making the LG02 swinging
arm retract too far.
I tried backing off the M8 stiffnuts a little (which involved removing and
re-installing the bungee again - nobody mentioned how hard it is to thread
the bungee around LG02B anchor tube) and that did seem to allow a little but
more movement in the up direction but nowhere near enough to get the lever
into the up gate. While looking at everything after that adjustment, it
seems that the linkage is not quite going over-centre in the down
position - it appears the 3 pivots are just about in line with each other. I
wonder if lengthening the suspension assembly has caused that.
Can anyone suggest what I might be doing wrong, please, or any way to solve
the problem?
in friendship
Rowland
| Rowland Carson ... that's Rowland with a 'w' ...
| <rowlandcarson@gmail.com> http://www.rowlandcarson.org.uk
| Skype, Twitter: rowland_carson Facebook: Rowland Carson
| pictures: http://picasaweb.google.com/rowlandcarson
Message 10
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: undercarriage retraction problem |
Keith - right on - it WAS Ron Parigoris who wrote about this at some length a few
years ago - sorry Ron, I couldn't remember who it was. If Ron reads this perhaps
he might be kind enough to reproduce his e-mails again for the benefit
of our fading memories! Cheers,
--------
G-TERN
Classic Mono
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=443175#443175
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|