Today's Message Index:
----------------------
1. 12:28 AM - Re: Vapour lock? Why? (Frans Veldman)
2. 12:46 AM - Re: Re: Cracks on the cockpit module near to the seat belts (Duncan & Ami)
3. 01:00 AM - Re: Vapour lock? Why? (PHILLIPS I)
4. 01:34 AM - Re: Possible New Build /Sywell LAA rally this weekend (K BURNS)
5. 03:11 AM - Re: Re: Cracks on the cockpit module near to the seat belts (Ivan Shaw)
6. 03:27 AM - Re: Vapour lock? Why? (Frans Veldman)
7. 05:42 AM - Re: Vapour lock? Why? (klinefelter.kevin@gmail.com)
8. 06:21 AM - Re: Re: Landing mishap/ prop twist (Duncan & Ami)
9. 06:34 AM - Re: Vapour lock? Why? (PHILLIPS I)
10. 06:55 AM - Re: Re: Landing mishap/ prop twist (David Joyce)
11. 12:52 PM - Re: Re: XS Exhaust System Cracks (Bud Yerly)
12. 01:21 PM - Re: Re: XS Exhaust System Cracks (Frans Veldman)
13. 01:29 PM - Re: Re: Cracks on the cockpit module near to the seat belts (Bud Yerly)
14. 03:04 PM - Vertical trim friction device (Frans Veldman)
15. 03:52 PM - Re: XS Exhaust System Cracks (JonSmith)
16. 06:20 PM - Re: Re: XS Exhaust System Cracks (Bud Yerly)
17. 09:37 PM - Ventilation ... (=?iso-8859-1?Q?Gert_Dalgaard_S=F8rensen?=)
Message 1
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| Subject: | Re: Vapour lock? Why? |
Hi Kevin,
> Frans, My engine symptoms were not constant. Only at high power.
Mine are not even constant at high power. Only temporary. After a few
seconds the engine runs fine at full power, even at altitude.
> Your
> symptoms sound similar. Momentary drop in fuel differential pressure.
Ok, this momentary drop in fuel pressure is interesting and sounds
similar indeed.
> I only changed the float bowl gaskets and that fixed it.
All right. I'm about to take the carbs out for examination anyway, so I
will replace the float bowl gaskets and see what that does for me.
> Could be when the turbo pressure goes up, the fuel pressure leaks out
> of a carb bowl gasket.
Yes, but why only temporary? This is what nags me. You may be right
about the gaskets, I will try it, but I also like to understand what is
happening and why it is happening the way it is.
> In the Rotax classes I took (Rotech in Canada who also run
> Rotax-owner.com) they emphasized always suspecting and ruling out
> carburetor problems first. They also told us that the cork gaskets
> are better than the paper ones. Bob Borger sent an eBay link a while
> back for nitrile gaskets. I bought a pair but have not installed
> them.
If I remember correctly I have the cork gaskets. I will replace them
with nitrile gaskets if I can get them.
Thanks,
Frans
Message 2
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| Subject: | Re: Cracks on the cockpit module near to the seat belts |
Doesn't really matter which cloth, as the replacement cloth will be
carrying
al of the load across the cracks.
Number of plies can be determined by burning a sample taken from the
damaged
area.
D McF.
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Paul
McAllister
Sent: 26 August 2012 15:15
Subject: Re: Europa-List: Re: Cracks on the cockpit module near to the
seat
belts
Duncan,
Thanks for posting this, I have been meaning to post something similar
so
you have saved me the trouble of going into the detail.
Jacques, the only thing I would like to add is that ideally you need to
use
the same cloth that was used in the original construction. In this case
it
might prove difficult because pre-preg bid was probably used in
manufacture.
The reason you need to do this is that using a material that is
significantly different means that this material may carry more (or
less) of
the required load and become a source of stress in of its self.
I would see if you can get a response from Nev or Ivan to to find out
how
many layers of material were used and what sort of cloth was used. I
know
that when I did a repair on my wing I was fortunate enough to be able to
get
the exact cloth that was not pre-preg'd. Ask them is it the same cloth
that
was used in the wing. If it was then I have a small amount of this and
I
can send it to you.
Failing that, it wouldn't be horrible if you can't match the cloth, but
do
try and find out how many layers were in the original construction.
Paul
On Sun, Aug 26, 2012 at 3:11 AM, Duncan & Ami
<ami-mcfadyean@talktalk.net>
wrote:
<ami-mcfadyean@talktalk.net>
<<..Any advice is welcome. .>>
OK, I'll bite!
During a monowheel collapse, the weight of the aircraft (less tailwheel
and
outrigger loads) is transferred from the monowheel in to the top of the
'tunnel'. Thereafter, the stress-path from the tunnel is mostly both
forwards and aftwards. In the aft direction the tunnel distributes loads
in
to the seatback bulkhead then further in to the fuselage skin. This
means
that the area that has cracked (being at along this stress-path is
taking
abnormal loads and this is a possible cause of the cracking, as you have
surmised, compounded by the holes that have been cut at that point.
Assuming there is no evidence of any other overstress in that area, the
repair needs to put back the strength lost. This means replication of
the
original strength of composite in that location, which can be determined
by
counting the number of plies present. Allow a minimum 1/2 inch per ply
overlap on to the surrounding unaffected area (presuming a bond shear
strength of 500psi and cloth strength of 250lbs/in) with staggered
edges. If
the holes must be recut, then double the reinforcement and cut the holes
as
ellipses (at a length:width ratio of 1.414:1, if you want to be
pedantic!).
Too much or overdesigned reinforcement may make the area too stiff and
introduce other issues, and makes the aircraft heavy too!
Your respective airworthiness and/or design authority will be the final
arbiter of any repair, which might be along the lines of the above.
Duncan McF.
Message 3
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| Subject: | Re: Vapour lock? Why? |
Hi Frans
A couple of month=92s ago I noticed fuel staining from my float bowls, so
decided to replace the gaskets with the nitrile type,
My experience were they are next to useless,
They are too soft, as you tighten the bowl they squeeze out and leak far
worst than the standard paper ones, The reason I didn=92t use the cork
gasket is they dissolve in ethanol so I didn=92t want a additional problem
if
any mogas I use is (contaminated) with it,
With the nitrile gaskets leaking as opposed to weeping paper ones I
couldn=92t get the the Engine pass 3000 rpm, With new paper ones it all bac
k
to normal even with a
40C takeoff from Croatia last week
Ivor
On 27 August 2012 09:20, Frans Veldman <frans@privatepilots.nl> wrote:
>
> Hi Kevin,
>
> > Frans, My engine symptoms were not constant. Only at high power.
>
> Mine are not even constant at high power. Only temporary. After a few
> seconds the engine runs fine at full power, even at altitude.
>
> > Your
> > symptoms sound similar. Momentary drop in fuel differential pressure.
>
> Ok, this momentary drop in fuel pressure is interesting and sounds
> similar indeed.
>
> > I only changed the float bowl gaskets and that fixed it.
>
> All right. I'm about to take the carbs out for examination anyway, so I
> will replace the float bowl gaskets and see what that does for me.
>
> > Could be when the turbo pressure goes up, the fuel pressure leaks out
> > of a carb bowl gasket.
>
> Yes, but why only temporary? This is what nags me. You may be right
> about the gaskets, I will try it, but I also like to understand what is
> happening and why it is happening the way it is.
>
> > In the Rotax classes I took (Rotech in Canada who also run
> > Rotax-owner.com) they emphasized always suspecting and ruling out
> > carburetor problems first. They also told us that the cork gaskets
> > are better than the paper ones. Bob Borger sent an eBay link a while
> > back for nitrile gaskets. I bought a pair but have not installed
> > them.
>
> If I remember correctly I have the cork gaskets. I will replace them
> with nitrile gaskets if I can get them.
>
> Thanks,
>
> Frans
>
===========
===========
===========
===========
>
>
Message 4
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| Subject: | Re: Possible New Build /Sywell LAA rally this weekend |
Steve=0AWhen you are at the rally look up Richard Kilham and crew,-I can
recommend him as a first class LAA inspector with a a wealth of composite k
nowledge who can advise or assist in any stage of construction or repair, h
as fly in facilities with hangerage-with a paint shop and Rotax people al
so on site-when required...5 min fly time from Sywell (LE17 6JJ)-also .
..and staff will be in the hanger Friday and Saturday for the occasional vi
sitor-, his contact details are here http://www.eastofenglandsailplanes.c
o.uk/about_us.html--=0A=0A- Regards=0AKevin Burns=0A=0A______________
__________________=0A From: G-IANI <g-iani@ntlworld.com>=0ATo: europa-list@
matronics.com =0ASent: Monday, 30 July 2012, 23:05=0ASubject: RE: Europa-Li
st: Possible New Build=0A =0A=0ASteve=0A-=0AYou might be interested in t
he attached.=0A-=0A-=0AIan Rickard G-IANI XS Trigear, 300hours=0AEuropa
Club Mods Specialist=0Ae-mail g-iani@ntlworld.com=0A-=0A-=0A-=0AFrom
:owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@ma
tronics.com] On Behalf Of Steve Robinson=0ASent: 18 July 2012 16:50=0ATo: e
uropa-list@matronics.com=0ASubject: Europa-List: Possible New Build=0A-
=0AHi, I'm seriously thinking about building a Europa XS with my two sons,
near Newbury, UK.=0AI would like to see a build in progress if possible to
see where the pitfalls might be, workshop considerations, talk through what
's involved etc.=0AI will try and get to the LAA sywell rally at the end of
august too before we take the plunge..=0AAny current builds in the south U
K willing to open their doors to us for an afternoon?=0ASteve.=0A-=0A-
=0Ahttp://www.matronics.com/Navigator?Europa-List=0Ahttp://forums.matronics
.com=0Ahttp://www.matronics.com/contribution
Message 5
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| Subject: | Re: Cracks on the cockpit module near to the seat belts |
The only comment I have to add is that it is generally wise with 'small'
repair areas to, after replacing what was there with same strength cloth and
ply orientation, overlapping plies half an inch is to add one ply of bid
over the whole repair area as a belt and braces, peal plying all the edges
or the whole repair if a small area. This covers the possibility of lack of
strength due to less than perfect layup conditions/lack of perfect
preparation etc, when done 'in the field'
Ivan
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Duncan & Ami
Sent: 27 August 2012 08:46
Subject: RE: Europa-List: Re: Cracks on the cockpit module near to the seat
belts
Doesn't really matter which cloth, as the replacement cloth will be carrying
al of the load across the cracks.
Number of plies can be determined by burning a sample taken from the damaged
area.
D McF.
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Paul McAllister
Sent: 26 August 2012 15:15
Subject: Re: Europa-List: Re: Cracks on the cockpit module near to the seat
belts
Duncan,
Thanks for posting this, I have been meaning to post something similar so
you have saved me the trouble of going into the detail.
Jacques, the only thing I would like to add is that ideally you need to use
the same cloth that was used in the original construction. In this case it
might prove difficult because pre-preg bid was probably used in manufacture.
The reason you need to do this is that using a material that is
significantly different means that this material may carry more (or less) of
the required load and become a source of stress in of its self.
I would see if you can get a response from Nev or Ivan to to find out how
many layers of material were used and what sort of cloth was used. I know
that when I did a repair on my wing I was fortunate enough to be able to get
the exact cloth that was not pre-preg'd. Ask them is it the same cloth that
was used in the wing. If it was then I have a small amount of this and I
can send it to you.
Failing that, it wouldn't be horrible if you can't match the cloth, but do
try and find out how many layers were in the original construction.
Paul
On Sun, Aug 26, 2012 at 3:11 AM, Duncan & Ami <ami-mcfadyean@talktalk.net>
wrote:
<ami-mcfadyean@talktalk.net>
<<..Any advice is welcome. .>>
OK, I'll bite!
During a monowheel collapse, the weight of the aircraft (less tailwheel and
outrigger loads) is transferred from the monowheel in to the top of the
'tunnel'. Thereafter, the stress-path from the tunnel is mostly both
forwards and aftwards. In the aft direction the tunnel distributes loads in
to the seatback bulkhead then further in to the fuselage skin. This means
that the area that has cracked (being at along this stress-path is taking
abnormal loads and this is a possible cause of the cracking, as you have
surmised, compounded by the holes that have been cut at that point.
Assuming there is no evidence of any other overstress in that area, the
repair needs to put back the strength lost. This means replication of the
original strength of composite in that location, which can be determined by
counting the number of plies present. Allow a minimum 1/2 inch per ply
overlap on to the surrounding unaffected area (presuming a bond shear
strength of 500psi and cloth strength of 250lbs/in) with staggered edges. If
the holes must be recut, then double the reinforcement and cut the holes as
ellipses (at a length:width ratio of 1.414:1, if you want to be pedantic!).
Too much or overdesigned reinforcement may make the area too stiff and
introduce other issues, and makes the aircraft heavy too!
Your respective airworthiness and/or design authority will be the final
arbiter of any repair, which might be along the lines of the above.
Duncan McF.
href="http://www.matronics.com/Navigator?Europa-List">http://www.matronhref
<http://www.matronhref=%22http:/forums.matronics.com%22%3ehttp:/forums.matro
nics.com> "http://forums.matronics.com">http://forums.matronics.com
href="http://www.matronics.com/contribution">http://www.matronics.com/c
No virus found in this message.
Checked by AVG - www.avg.com
Message 6
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| Subject: | Re: Vapour lock? Why? |
Hi Ivor,
> A couple of months ago I noticed fuel staining from my float bowls, so
> decided to replace the gaskets with the nitrile type,
>
> My experience were they are next to useless,
Great. I just ordered 4 of them.
Has anyone else tried these gaskets as well? I know some of us ordered
them, but has anyone actually tried to use them?
If they are indeed too soft, maybe we should apply less torque? The
recommended torque is obviously determined for best seal with the
original gaskets. I think I will just apply enough torque to get it
correct by feel and look (and still use a torque spanner to make sure I
at least don't overtorque.)
> 40C takeoff from Croatia last week
Hey, we have been to Croatia recently as well. Which field(s) did you
do? We've done Brac, Trogir (Split) as a diversion because Brac was
closed, Unije, Pula (for customs only). We certainly want to go back to
Brac and Unije. We found Landshut in Germany a very friendly EU-entry
airport... with an excellent Croatian restaurant. :-)
Frans
Message 7
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| Subject: | Re: Vapour lock? Why? |
"Mine are not even constant at high power. Only temporary. After a few
seconds the engine runs fine at full power, even at altitude."
That is different. I hope your carb inspections reveal something.
Kevin
On Aug 27, 2012, at 1:20 AM, Frans Veldman <frans@privatepilots.nl> wrote:
> Mine are not even constant at high power. Only temporary. After a few
> seconds the engine runs fine at full power, even at altitude.
Message 8
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| Subject: | Re: Landing mishap/ prop twist |
<<.whereas 12 degrees (your Warp drive blade)>>
David the Warp has 19.5 degrees twist at 72" diameter, as measured to the
point that the undersurface no longer has a point that is flat. All other
incarnations of the Warp Drive come from the same mould and are cut down to
the required size.
Removing 5" from the tip of a Warp Drive takes off about 1.75 degree of
twist; I have some tips spare if you'd like one!
Whilst this twist is measured from the point adjacent to the root where the
underside still has a flat area; it could be argued that measuring from
closer to the root where there is at least a 3:1 symmetrical airfoil section
will indicate more twist.
Not forgetting that an asymmetrical aerofoil will need at least a few
degrees of negative incidence before it starts to generate 'reverse thrust'.
I agree that there's not enough!
The fixed pitch Arplast has more twist (about 22 degrees), and other
versions (the faster VP blade) more still.
Duncan McF.
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of David Joyce
Sent: 25 August 2012 12:20
Subject: Re: Europa-List: Re: Landing mishap/ prop twist
--> <davidjoyce@doctors.org.uk>
Duncan, As all Europa props are close to 1600mm it makes
very little difference. The actual maths are set out in
the article 'Does propeller twist matter?' in Europa Flyer
no 65 (available like all back numbers on the beautiful
new Europa Club website at
www.theeuropaclub.org/the-club/europa-flyer/ ). For a
1600mm prop, the amount of twist needed rises rapidly from
6 degrees at 20 kts to 24 at 100kts but then levels off to
just 29 degrees at 160 kts before coming down somewhat at
higher speeds. As the curve flattens out in the working
range an increase in diameter just moves you marginally
along this relatively flat segment. In practice 26
degrees is within 3 degrees of optimal for speeds between
90 odd kts and 200+ kts, whereas 12 degrees (your Warp
drive blade) is optimal for sitting stationary on the
ground with the throttle half open (this giving an airflow
of 40kts past the cock[pit!)
Regards, David
On Sat, 25 Aug 2012 10:12:17 +0100
"Duncan & Ami" <ami-mcfadyean@talktalk.net> wrote:
><ami-mcfadyean@talktalk.net>
>
> You'll also need to measure the diameter for any
>meaningful comparison;
> generally, as diameter increases, the required overall
>prop twist along the
> blade needs to be slightly less.
> Then there's the fact that most manufactured blades in
>our class of use
> (e.g. Warp Drive, Arplast) start off as a larger
>diameter prop (with a
> better amount of twist) which is then cut down to the
>required diameter.
> This of course removes twist, usually to well below the
>optimum!
>
> Duncan McF.
>
> -----Original Message-----
>From: owner-europa-list-server@matronics.com
> [mailto:owner-europa-list-server@matronics.com] On
>Behalf Of zwakie
> Sent: 21 August 2012 20:57
> To: europa-list@matronics.com
> Subject: Europa-List: Re: Landing mishap - asking for
>advise
>
>
><mz@cariama.nl>
>
> David, Graham and others,
>
> I will take it upon myself to come up with the numbers
>on the twist of the
> Arplast PV50 and publish them here in due time.
>
> --------
> Marcel
> (Europa Classic Tri-Gear PH-MZW)
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=381475#381475
>
>
>
>
>
>
>
>
>
>
>
>
>
>Un/Subscription,
>Forums!
>Admin.
>
>
>
Message 9
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| Subject: | Re: Vapour lock? Why? |
Hi Fran's
Hope you fair better with the nitrile gaskets than me, but I would also
order a pair of paper gaskets Just in case,
Bob Harrison and I Landed at Losinj a beautiful Island south of Paula,
Then down to Dubrovnik, On the way back we flew into Portoroz Slovenia to
get back in the EU to cut down the hassle flying into Italy,
It was a great trip just a fair bit hotter than I would like,
Hope to see you at the LAA rally this weekend,
Regards
ivor
On 27 August 2012 12:19, Frans Veldman <frans@privatepilots.nl> wrote:
>
> Hi Ivor,
>
> > A couple of month=92s ago I noticed fuel staining from my float bowls,
so
> > decided to replace the gaskets with the nitrile type,
> >
> > My experience were they are next to useless,
>
> Great. I just ordered 4 of them.
> Has anyone else tried these gaskets as well? I know some of us ordered
> them, but has anyone actually tried to use them?
>
> If they are indeed too soft, maybe we should apply less torque? The
> recommended torque is obviously determined for best seal with the
> original gaskets. I think I will just apply enough torque to get it
> correct by feel and look (and still use a torque spanner to make sure I
> at least don't overtorque.)
>
> > 40C takeoff from Croatia last week
>
> Hey, we have been to Croatia recently as well. Which field(s) did you
> do? We've done Brac, Trogir (Split) as a diversion because Brac was
> closed, Unije, Pula (for customs only). We certainly want to go back to
> Brac and Unije. We found Landshut in Germany a very friendly EU-entry
> airport... with an excellent Croatian restaurant. :-)
>
> Frans
>
>
===========
===========
===========
===========
>
>
Message 10
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| Subject: | Re: Landing mishap/ prop twist |
Duncan, when I wrote my article I was not able to come by
any definition of twist so took the difference in pitch at
tip and 1/3 radius. If you are measuring somewhere else
then it isn't possible to make comparisons, but at the
time Europa Warp drive blades were around 12 degrees
measured thus.
Regards, David
On Mon, 27 Aug 2012 14:20:51 +0100
"Duncan & Ami" <ami-mcfadyean@talktalk.net> wrote:
><ami-mcfadyean@talktalk.net>
>
> <<.whereas 12 degrees (your Warp drive blade)>>
> David the Warp has 19.5 degrees twist at 72" diameter,
>as measured to the
> point that the undersurface no longer has a point that
>is flat. All other
> incarnations of the Warp Drive come from the same mould
>and are cut down to
> the required size.
> Removing 5" from the tip of a Warp Drive takes off about
>1.75 degree of
> twist; I have some tips spare if you'd like one!
>
> Whilst this twist is measured from the point adjacent to
>the root where the
> underside still has a flat area; it could be argued that
>measuring from
> closer to the root where there is at least a 3:1
>symmetrical airfoil section
> will indicate more twist.
>
> Not forgetting that an asymmetrical aerofoil will need
>at least a few
> degrees of negative incidence before it starts to
>generate 'reverse thrust'.
> I agree that there's not enough!
>
> The fixed pitch Arplast has more twist (about 22
>degrees), and other
> versions (the faster VP blade) more still.
>
>
>
> Duncan McF.
>
> -----Original Message-----
>From: owner-europa-list-server@matronics.com
> [mailto:owner-europa-list-server@matronics.com] On
>Behalf Of David Joyce
> Sent: 25 August 2012 12:20
> To: europa-list@matronics.com
> Subject: Re: Europa-List: Re: Landing mishap/ prop twist
>
>
> --> <davidjoyce@doctors.org.uk>
>
> Duncan, As all Europa props are close to 1600mm it makes
> very little difference. The actual maths are set out in
> the article 'Does propeller twist matter?' in Europa
>Flyer
> no 65 (available like all back numbers on the beautiful
> new Europa Club website at
> www.theeuropaclub.org/the-club/europa-flyer/ ). For a
> 1600mm prop, the amount of twist needed rises rapidly
>from
> 6 degrees at 20 kts to 24 at 100kts but then levels off
>to
> just 29 degrees at 160 kts before coming down somewhat
>at
> higher speeds. As the curve flattens out in the working
> range an increase in diameter just moves you marginally
> along this relatively flat segment. In practice 26
> degrees is within 3 degrees of optimal for speeds
>between
> 90 odd kts and 200+ kts, whereas 12 degrees (your Warp
> drive blade) is optimal for sitting stationary on the
> ground with the throttle half open (this giving an
>airflow
> of 40kts past the cock[pit!)
> Regards, David
>
>
> On Sat, 25 Aug 2012 10:12:17 +0100
> "Duncan & Ami" <ami-mcfadyean@talktalk.net> wrote:
>><ami-mcfadyean@talktalk.net>
>>
>> You'll also need to measure the diameter for any
>>meaningful comparison;
>> generally, as diameter increases, the required overall
>>prop twist along the
>> blade needs to be slightly less.
>> Then there's the fact that most manufactured blades in
>>our class of use
>> (e.g. Warp Drive, Arplast) start off as a larger
>>diameter prop (with a
>> better amount of twist) which is then cut down to the
>>required diameter.
>> This of course removes twist, usually to well below the
>>optimum!
>>
>> Duncan McF.
>>
>> -----Original Message-----
>>From: owner-europa-list-server@matronics.com
>> [mailto:owner-europa-list-server@matronics.com] On
>>Behalf Of zwakie
>> Sent: 21 August 2012 20:57
>> To: europa-list@matronics.com
>> Subject: Europa-List: Re: Landing mishap - asking for
>>advise
>>
>>
>><mz@cariama.nl>
>>
>> David, Graham and others,
>>
>> I will take it upon myself to come up with the numbers
>>on the twist of the
>> Arplast PV50 and publish them here in due time.
>>
>> --------
>> Marcel
>> (Europa Classic Tri-Gear PH-MZW)
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=381475#381475
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>Un/Subscription,
>>Forums!
>>Admin.
>>
>>
>>
>
>
>
>
>
>
>
>
>Un/Subscription,
>Forums!
>Admin.
>
>
>
Message 11
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| Subject: | Re: XS Exhaust System Cracks |
Jon and Pete,
I have the same problem on two 912S engines on #3 and #1 cylinder.
One is clearly a tune problem which causes excessive vibration of the
muffler and clear engine shake...
The other was more interesting. The pipe and spring combination seems
to resonate during runs about 5000 RPM. I may have a harmonic problem.
Chris Piper (CKT) and I have discussed the problem and we are going to
stainless springs and then checking again, but the engine has a left to
right shake that causes the muffler to want to swing back and forth
under the engine, but of course the exhaust bolts and friction prevent
that, and the pipe seems to fail.
The spring fails then the pipe I expected went before the spring, but
don't know for sure. Tuning the engine was the first step. As we all
know, the 912S is a bit rough on start and stop, but generally smooth
once above 2500 RPM. However, with the fixed pitch props when entering
the pattern at 130 knots then throttling back for downwind, the prop (a
Warp Drive on an Airmaster manual not auto control) tends to vibrate a
bit during de-acceleration and the engine vibration is quite noticeable
in the feel, but not visually. We broke #1 spring and safety wire from
the vibration. #1 has an adjustable leg of course and did not crack the
pipe. But I am concerned. Something is vibrating at a harmonic down
there.
I am at a loss at the reason for the vibration crack on only one
cylinder. One would think it would affect more than one pipe. Our
checks were:
Does the silencer hit anything on the engine or frame? No.
Is the engine in tune. Yes
Is the prop balanced. Yes
Is the prop blade tracking true. Yes
Is the prop blade angle true. Yes
Is the pipe overcooled by ram air. Not really
Are the springs tight with no twist or torque imparted. Yes
Is the pipe securely seated in the silencer. Yes
Is the pipe over-torqued. No.
Does the crack start at a weld. Possibly.
Are the engine mounts sound and firm. Yes
Are the engine attach bolts and frame secure. Yes
I'm running out of ideas myself.
Regards and still looking for the solution:
Bud Yerly
Custom Flight Creations, Inc.
www.customflightcreations.com<http://www.customflightcreations.com/>
(813) 653-4989
----- Original Message -----
From: Pete Lawless<mailto:pete@lawless.info>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Friday, August 24, 2012 2:58 PM
Subject: RE: Europa-List: Re: XS Exhaust System Cracks
<pete@lawless.info<mailto:pete@lawless.info>>
Hi Jon
My crack ran along the inside of the bend along the length of the
pipe,
rather than round it. It is noticeable that the crack is just along
the
bottom of the weld for the exhaust spring, though if that is anything
to do
with the problem I could not say.
We had fun with the CKT exhaust pipes last year 3 of the 4 flanges(?)
where
they bolt to the heads cracked off. The replacements are considerably
better welded.
I dealt with CKT direct for my replacements. Chris Piper is the man
to talk
to. 01884 242211 if you need the number.
Pete
PS I seem to remember G-TERN parked outside the hanger at Kemble?
-----Original Message-----
From:
owner-europa-list-server@matronics.com<mailto:owner-europa-list-server@ma
tronics.com>
[mailto:owner-europa-list-server@matronics.com] On Behalf Of JonSmith
Sent: 24 August 2012 19:20
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Subject: Europa-List: Re: XS Exhaust System Cracks
<jonsmitheuropa@tiscali.co.uk<mailto:jonsmitheuropa@tiscali.co.uk>>
Hi Pete, thanks for your reply. I should have said that mine already
is an
XS version, stainless steel by CKT. On mine its both the rear pipes
that
keep cracking (twice for both of them). The front ones have so far
been ok.
Attached is a photo of one of the rear pipes - the other was similar.
Cheers, Jon
--------
G-TERN
Classic Mono
Read this topic online here:
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Message 12
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| Subject: | Re: XS Exhaust System Cracks |
On 08/27/2012 09:52 PM, Bud Yerly wrote:
> We broke #1 spring and safety
> wire from the vibration. #1 has an adjustable leg of course and did not
> crack the pipe. But I am concerned. Something is vibrating at a
> harmonic down there.
>
> I'm running out of ideas myself.
Try to support the #1, somewhere near the middle. I literally mean
"near", make sure you don't accidentially hit the middle. At least try
to avoid the 1/2 and 1/3 point. This will likely dampen out the close
harmonics.
This would be the most easy solution. Otherwise you have to change the
lenght of the pipe, or to chase the vibration which is likely a
byproduct of the engine/prop combination.
Frans
Message 13
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| Subject: | Re: Cracks on the cockpit module near to the seat belts |
Jacques,
I have just been able to see your photos of your cracks.
As others and you suspect, the crack was the result of the gear up
landing and the main wheel and arm impacting the top of the gear well
(and the choke, throttle, locking arm and all the other stuff) and
forcing the module to bend upward. The aft bulkhead to rear back rest
distance is short and the stress looks to be a tension crack.
The area should be de-painted by sanding carefully to the upper layer of
glass and the glass properly inspected as well as the Redux (Araldite
420A/B) joints in that area. Rudder cable, fuel lines, etc. should be
removed to provide for proper visual inspection and repair...
The layup repair is similar to any composite repair. Grind down the
crack and taper. Fill the foam with flox and glass with 2 layers of bid
inside and out with the overlap to be at least 2 inches either side of
the crack. Delamination of the Redux joints in the module must be
checked also. Tapping with a large coin or drift can detect a hollow
sound and possible delamination of your glue joint.
I prefer not to paint the interior of an airplane but it is expedient as
an interior, however, it makes inspection more difficult and can hide
damage.
I do not have a specific gear up landing checklist for my guys, but I
have them use our hard landing checklist to start, which is attached.
Basically, on a gear up we remove the gear and inspect and repair the
well and cockpit, because there is a good chance damage has occurred
unless the collapse was very benign.
Please to a de-paint and do a thorough inspection. Tape up the
instrument panel or remove it and grind away. There is a 50/50 chance
that this is the only damage. However I'm unlucky and a 50/50 chance
seems to be a 100% chance of more problems.
Regards,
Bud Yerly
Europa Tech Support,
or
Custom Flight Creations, Inc.
www.customflightcreations.com<http://www.customflightcreations.com/>
(813) 653-4989
----- Original Message -----
From: ploucandco<mailto:jacques@platisource.com>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Friday, August 24, 2012 4:04 AM
Subject: Europa-List: Re: Cracks on the cockpit module near to the
seat belts
<jacques@platisource.com<mailto:jacques@platisource.com>>
Hello, do others see the pictures? I checked with Explorer and Chrome
and both show me the pictures.
Thanks for advice, Jacques.
Read this topic online here:
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Message 14
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| Subject: | Vertical trim friction device |
Hi,
When checking the aircraft (without the tailplanes installed) I
discovered that the vertical trim motor sounds like it is running
without load briefly just after changing trim direction.
Further examination revealed that this is caused by the friction device
in the trim mechanism. This thing is (by design) out of the center of
the trim bellcrank, and therefore it bends/realigns a bit before it
starts pulling through the friction slot.
Looking at it when changing trim direction repeatedly, I observed that
the whole frame torques a bit due to the friction and change of angle of
the center bolt. I guess this is normal, but of course at the end it may
cause metal fatique.
There is no hint in the manual how to set this friction contraption,
neither is there an explanation why we need it. For small trim
deviations the thing is useless anyway because of the slack in the
system due to bending and torqueing of the various components.
Has anyone any insight in the purpose of this friction device and how we
are supposed to set it? Have others also observed the slack in the
system and bending/torqueing of the frame?
Frans
Message 15
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| Subject: | Re: XS Exhaust System Cracks |
Hi Bud, Many thanks for your input on this. Interesting to hear about the problems
you've had too. Just to give you some data from me, my problem has been both
the rear pipes cracking, ie cyls 3 and 4. I first found them both cracked
together after about 15 hours flying on my new engine installation. They were
both cracked about 75% around the circumference inside the tightest part of the
bend. They may have been like that for quite a while as they are almost impossible
to spot without a mirror when in situ. It was taking no. 3 off to fit
the new HD starter I quite by chance found it cracked. I had them both welded
up. After about 2 more hours flying I found no. 3 cracked again, following almost
exactly the same line as the first time (but not quite on the weld repair
- it was fresh metal that was failed rather than the repair itself). I had
it welded again. Since then I did just a quick 20 minute flight and have found
no. 4 has cracked again, same pattern. So each rear pipe has cracked twice
now. Both front pipes have been ok to date. The cracks do seem to run through
where the spring attachment loops are welded on as my previous picture shows.
As far as I am aware my springs are stainless - as supplied by Europa (they
look stainless to me!). The engine runs very smoothly - as you say it can be
a bit clunky on start/ stop but not excessively. My propeller is a BSW (Bog Standard
Warp!) ground adjustable 64" non tapered blades warpdrive fitted to my
912 ULS. I always keep the carbs well sync'd. I do notice sometimes a slight
vibration during slowing down and/ or descending - if flying fast at a high power
setting when I reduce power at high speed, at a certain point during the
power reduction - usually when the throttle has been brought a fair way back a
slight vibration/ resonance can sometimes suddenly kick in but it's only ever
very slight, a slight tremble than an actual vibration. More of a slight change
in sound. I've never thought anything of it. I don't really know where to
go with t!
his now
as it seems to be an ongoing problem I have and I can't really fault anything else
in my setup.
Cheers, Jon
--------
G-TERN
Classic Mono
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=381946#381946
Message 16
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| Subject: | Re: XS Exhaust System Cracks |
Hohn,
I doubt that the setup is wrong.
My concerns on vibration is two fold.
First is crank shaft alignment. Having a love hate relationship with
all things airplane, I am not criticizing the Rotax, but it is possible
since it is a 5 section crank shaft or so, the shaft may have slipped as
it is only pressed together. This is highly unlikely unless the engine
was bought used and had a prop strike that was undisclosed. In this
case the engine vibrates is over a wide range of RPMs. I had a 914
with this problem once. It never balanced right.
Next is that the cracks indicate to me that the failure is due to
lateral movement of the silencer, or attempted movement, which is
restrained by the pipes. This side to side stress means the harmonic
could be coming from the piston induced horizontal vibration of the
boxer engine. This could be from a lack of proper harmonic balancing of
the crank which is corrected by use of a rotating weight or other means
such as crank shaft lobes to dampen the harmonics. Since many LSA
aircraft fly with the 912S, I doubt that they have recorded exhaust
problems we can draw from so we are in the blind right now. I know the
Ran's aircraft 912S installations have no exhaust pipe problems to speak
of, but they do get failures at the weld points occasionally. I have
never studied the exhaust pipe springs and silencer movement closely on
the ground engine run-ups in our aircraft, and probably should.
Frans correctly noted that the exhaust needs support or exhaust pipe
dimensions changes, to affect changes to the harmonic. Problems arise
with supporting the exhaust as it does move with heat, and can only be
supported to the engine such as on the 914. Perhaps some stainless
brackets supporting the silencer to the frame may be appropriate. An X
type support comes to mind on the aft pipes to stabilize the silencer.
Even a .041 stainless safety wire may work. The 912 has no problems
with this cracking problem in my shop, the 914 is supported extensively,
and only the 912S seems to have the issue. So must I assume it is an
engine specific problem. Probably not an accurate assumption as
usual...
My welder inspected the crack as did Chris Piper at CKT and the type of
stainless may be the problem, but the jury is still out on that. There
is not enough data on this problem. Chris at CKT, has solved the
horrible exhaust silencer failures of the past and beefed up the
previously anemic down pipes and I thought we were all right, then this
problem started to creep up. We are considering the pipe bend and weld
when under heat stress is the problem. Changing the material and heat
treating may solve this if it is not an engine related problem. Extra
support as Frans suggests may be necessary.
The Warp Drive and other props too, do vibrate under compression braking
during a de-acceleration but it is slight as you noted. This vibration
doesn't bother me as it is not constant and is only momentary and
changes in its harmonic (as measured by the giggle of my calf muscles
which are not registered with the bureau of standards). So if the
run-up and full power dynamic balance of the prop is fine, I am not
worried about the prop causing this problem.
More will come out. In the mean time, I will try a safety wire X brace
and see what happens.
Regards,
Bud
----- Original Message -----
From: JonSmith<mailto:jonsmitheuropa@tiscali.co.uk>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Monday, August 27, 2012 6:51 PM
Subject: Europa-List: Re: XS Exhaust System Cracks
<jonsmitheuropa@tiscali.co.uk<mailto:jonsmitheuropa@tiscali.co.uk>>
Hi Bud, Many thanks for your input on this. Interesting to hear about
the problems you've had too. Just to give you some data from me, my
problem has been both the rear pipes cracking, ie cyls 3 and 4. I first
found them both cracked together after about 15 hours flying on my new
engine installation. They were both cracked about 75% around the
circumference inside the tightest part of the bend. They may have been
like that for quite a while as they are almost impossible to spot
without a mirror when in situ. It was taking no. 3 off to fit the new
HD starter I quite by chance found it cracked. I had them both welded
up. After about 2 more hours flying I found no. 3 cracked again,
following almost exactly the same line as the first time (but not quite
on the weld repair - it was fresh metal that was failed rather than the
repair itself). I had it welded again. Since then I did just a quick
20 minute flight and have found no. 4 has cracked again, same pattern.
So each re!
ar pipe has cracked twice now. Both front pipes have been ok to
date. The cracks do seem to run through where the spring attachment
loops are welded on as my previous picture shows. As far as I am aware
my springs are stainless - as supplied by Europa (they look stainless to
me!). The engine runs very smoothly - as you say it can be a bit clunky
on start/ stop but not excessively. My propeller is a BSW (Bog Standard
Warp!) ground adjustable 64" non tapered blades warpdrive fitted to my
912 ULS. I always keep the carbs well sync'd. I do notice sometimes a
slight vibration during slowing down and/ or descending - if flying fast
at a high power setting when I reduce power at high speed, at a certain
point during the power reduction - usually when the throttle has been
brought a fair way back a slight vibration/ resonance can sometimes
suddenly kick in but it's only ever very slight, a slight tremble than
an actual vibration. More of a slight change in sound. I've never t!
hought anything of it. I don't really know where to go with t!
his now
as it seems to be an ongoing problem I have and I can't really fault
anything else in my setup.
Cheers, Jon
--------
G-TERN
Classic Mono
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=381946#381946<http://forums
.matronics.com/viewtopic.php?p=381946#381946>
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avigator?Europa-List>
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Message 17
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Hi
For a couple a months ago, we had a tread around cut-out for ventilation in the
cabin.
I have been flying with NACA cut outs for some years, but someone suggested another
"round" valve, and it looked very nice - now I am just not able to find that
thread ..... grrr..!!
Can someone help me .. ?
Regards
Gert Dalgaard
OY-GDS
Mono/914/500+ hours
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