Today's Message Index:
----------------------
1. 12:12 AM - Re: Trigear conversion; only 80hp. Advice please. (jonathanmilbank)
2. 01:12 AM - Re: Re: Cracks on the cockpit module near to the seat belts (Duncan & Ami)
3. 01:37 AM - Re: Vapour lock? Why? (Frans Veldman)
4. 03:25 AM - Re: Landing mishap - asking for advise (zwakie)
5. 03:44 AM - Anybody willing to pick me up for Dutch GA Fly-in? (zwakie)
6. 06:11 AM - Re: Vapour lock? Why? (klinefelter.kevin@gmail.com)
7. 07:15 AM - Re: Re: Cracks on the cockpit module near to the seat belts (Paul McAllister)
8. 08:12 AM - NSI controller (Kevin Challis)
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Subject: | Re: Trigear conversion; only 80hp. Advice please. |
Got it, thanks Gordon. I've emailed a reply to you.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=381859#381859
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Subject: | Re: Cracks on the cockpit module near to the seat belts |
<<..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.
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of ploucandco
Sent: 25 August 2012 18:26
Subject: Europa-List: Re: Cracks on the cockpit module near to the seat
belts
--> <jacques@platisource.com>
Hi all, here is a drawing of the cockpit module that shows with red
rectangles the place where the pictures have been taken and so the location
of the cracks. Will 5 BID at both side of the existing panel and on the
cracks location be enough to repair and prevent reoccurence?
Thanks, Jacques
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=381795#381795
Attachments:
http://forums.matronics.com//files/cockpit_module_158.jpg
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Subject: | Re: Vapour lock? Why? |
Hi Kevin,
> I was having a similar problem with my 914. Mine was running rough and stumbling
at high power, but only at altitudes above 10,000'.
> The fuel differential pressure gauge would drop and engine run worse with more
power applied.
I think my problem is different. The weird thing is that I'm looking at
a *momentary* drop in fuel pressure, during the first few seconds at
take off power. The fuel pressure then comes back up and the engine runs
fine. Now I'm 100% sure that there is sufficient fuel flow (pump and
filters are ok) it is a mystery why the fuel pressure drops. Note here
that I'm referring to the differential fuel pressure. So it looks like
when the turbo pressure goes up, the fuel pressure lags behind, to catch
up a few seconds later. That's why I suspect the fuel pressure
regulator. This is what you could expect when the regulator valve is
"sticky".
I'm also suspecting the carbs (including the carb bowl gaskets). However
it is a bit strange that the engine runs fine after a few seconds. From
your description of leaking carb bowl gaskets I get the impression that
your symptoms were of a more constant nature.
A carb slide with some friction could be an explanation for the
temporary nature of the problem, but I can't see a relation with the
fuel pressure here. If the slide misbehaves, you should't see a drop in
fuel pressure.
I have observed an overall slightly higher fuel consumption, based on
the fuel flow gauge. Having said that, it is a differential flow meter,
substracting the return flow from the main flow. As the main flow is
over 120 liters per hour, it is hard to say whether a measured fuel
consumpion increase of about 1 to 2 liters per hour is real or just a
small deviation in one of the two flow sensors. Also the carbs or entire
engine could be aging and the whole problem might be unrelated to the
power surge in the first few seconds of the take off.
Back to the fuel pressure regulator. I think that it should held
pressure in its reference port (the small hose connector in the lower
shell) but the air is leaking away rapidly, mostl likely internally,
i.e. via the fuel return hose. This would indicate a leaking diaphragm.
Can anyone confirm that this leak in the reference port is indeed a
fault? (This is not so obvious as I can imagine that the designers
choosed to deliberately incorporate a small leak to cope with a
potentially plugged reference port and to use ambiant pressure in that
case as a backup reference).
Frans
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Subject: | Re: Landing mishap - asking for advise |
Duncan McFadyean wrote:
> 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.--
Absolutely, goes without saying...
Update after doing more thorough checks yesterday (engine still attached, more
might creep up once engine is taken off):
Additional damage found:
- Propeller hub: a fine crack (appr. 3 cm long) protruding from the inset of the
prop blade that took the hardest hit.
- Small crack in the spinner.
No visible damage to:
- Engine mounts
- Landing gear frame
- Fuselage around engine frame attachment points
- Any parts connected to engine, including exhaust pipes
(geometry still needs to be checked)
--------
Marcel
(Europa Classic Tri-Gear PH-MZW)
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=381863#381863
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Subject: | Anybody willing to pick me up for Dutch GA Fly-in? |
I was planning to attend the Dutch GA Fly-in at 7-8-9 September at Texel (EHTX),
flying out there with PH-MZW.
After my landing mishap two weeks ago that no longer is an option, so I am looking
for alternative means of 'transportation by air'.
Is there anybody attending this fly-in that has a seat available and willing to
make an extra stop at Hoogeveen (EHHO) to pick me up and drop me off upon return?
--------
Marcel
(Europa Classic Tri-Gear PH-MZW)
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=381865#381865
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Subject: | Re: Vapour lock? Why? |
Frans,
My engine symptoms were not constant. Only at high power. Your symptoms sound similar.
Momentary drop in fuel differential pressure. I only changed the float
bowl gaskets and that fixed it.
Could be when the turbo pressure goes up, the fuel pressure leaks out of a carb
bowl gasket.
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.
I replaced the gaskets without pulling the carbs off the engine, which is faster
but a bit awkward. A wee bit of grease on the gasket will help it stay put upside-down
in the carb body till you replace the bowl. Over-torque of the retaining
bolt (that has an o-ring to inspect) can distort the bowl and cause float
problems.
The drip trays are such a pain with the little nuts and washers that I modified
them with nut plates. Much easier.
You must be about tired of this by now!
Best of luck,
Kevin
On Aug 26, 2012, at 2:29 AM, Frans Veldman <frans@privatepilots.nl> wrote:
>
> Hi Kevin,
>
>> I was having a similar problem with my 914. Mine was running rough and stumbling
at high power, but only at altitudes above 10,000'.
>> The fuel differential pressure gauge would drop and engine run worse with more
power applied.
>
> I think my problem is different. The weird thing is that I'm looking at
> a *momentary* drop in fuel pressure, during the first few seconds at
> take off power. The fuel pressure then comes back up and the engine runs
> fine. Now I'm 100% sure that there is sufficient fuel flow (pump and
> filters are ok) it is a mystery why the fuel pressure drops. Note here
> that I'm referring to the differential fuel pressure. So it looks like
> when the turbo pressure goes up, the fuel pressure lags behind, to catch
> up a few seconds later. That's why I suspect the fuel pressure
> regulator. This is what you could expect when the regulator valve is
> "sticky".
>
> I'm also suspecting the carbs (including the carb bowl gaskets). However
> it is a bit strange that the engine runs fine after a few seconds. From
> your description of leaking carb bowl gaskets I get the impression that
> your symptoms were of a more constant nature.
>
> A carb slide with some friction could be an explanation for the
> temporary nature of the problem, but I can't see a relation with the
> fuel pressure here. If the slide misbehaves, you should't see a drop in
> fuel pressure.
>
> I have observed an overall slightly higher fuel consumption, based on
> the fuel flow gauge. Having said that, it is a differential flow meter,
> substracting the return flow from the main flow. As the main flow is
> over 120 liters per hour, it is hard to say whether a measured fuel
> consumpion increase of about 1 to 2 liters per hour is real or just a
> small deviation in one of the two flow sensors. Also the carbs or entire
> engine could be aging and the whole problem might be unrelated to the
> power surge in the first few seconds of the take off.
>
> Back to the fuel pressure regulator. I think that it should held
> pressure in its reference port (the small hose connector in the lower
> shell) but the air is leaking away rapidly, mostl likely internally,
> i.e. via the fuel return hose. This would indicate a leaking diaphragm.
> Can anyone confirm that this leak in the reference port is indeed a
> fault? (This is not so obvious as I can imagine that the designers
> choosed to deliberately incorporate a small leak to cope with a
> potentially plugged reference port and to use ambiant pressure in that
> case as a backup reference).
>
> Frans
>
>
>
>
>
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Subject: | 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.
>
>
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Hi
A new second hand controller sourced from this forum. Fitted and all is well with
my prop.
Thank you for everyones help.
>From now on I will turn the power off to the controller when on the ground and
in fine. I was lucky that it went fully course at Biggin hill at the start of
my take off run as its a massive runway on top of a hill. It wouldn't have been
so good taking off from a 400m grass strip with high ground all around!
Kevin
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