Today's Message Index:
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1. 02:47 AM - Re: 914 w/intercooler induction air heating (Robert C Harrison)
2. 04:14 AM - Re: rotax 912 over-run experience (K Dilks)
3. 06:55 AM - Re: rotax 912 over-run experience (rampil)
4. 07:21 AM - Re: rotax 912 over-run experience (Roger Lee)
Message 1
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| Subject: | 914 w/intercooler induction air heating |
Hi! Gilles.
Happy New Year ...if not too late !
I was concerned about carb. ice with an intercooler fitted to my 914
installation. Especially when the Intercooler manufacturers (Bell) were
claiming 25deg temp drop in Winter and 20deg drop in Summer. I have a
crude temperature sensor reduxed into a plastic hollow tube to the port
carb throat and have never seen less than 6 deg Celsius. Even descending
on low power settings through thin cloud formation from 10,000ft after
the wind screen in my Europa began to frost over on the inside with
minimal cabin heat facility.
Whilst I do understand that carb ice conditions are very humidity and
ambient temperature connected this has left me "fairly" confident that
ice is not an issue ( I am reluctant to actually say that since next
flight ..!)
However Rotax do recommend a carb heat facility even with a turbo fitted
=85but this may be sales justified or more appropriate to tropical
applications in real terms.
My air filter is not of the air box type just a simple washable air
canister clipped to the turbo intake.
Regards
Bob Harrison G-PTAG Europa Kit 337 Now with Rotax 914.
-----Original Message-----
From: owner-rotaxengines-list-server@matronics.com
[mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of
Gilles Thesee
Sent: 28 January 2009 21:54
Subject: Re: RotaxEngines-List: 914 w/intercooler induction air heating
<Gilles.Thesee@ac-grenoble.fr>
Patrick and all,
> I am searching for some info on the temperature difference between
airbox temperature and ambient during flight. JAR 23.1093 states if the
temperature rise is more than 56 deg C when ambient temperature is -1
deg C at 60 % power there is no need for carb heating. In JAR-VLA 1093
the temperature rise should be 38 deg C with the same conditions. Has
anyone with a 914 w/intercooler done some flight tests? Installing carb
heating is a bit of a hassle so
Remember those rules have been written by people used to Lyco/Conti
aircooled engines, with hot air as the sole means of avoiding carb ice.
We are flying an MCR 4s with an intercooled 914. Due to our engine
installation peculiarities, our carb temperatures are within the
40-50=B0C
range in flight. Whatever the air temperature, remember ice cannot build
up on warm metal.
But it all depends on your particular engine installation.
With a proper airbox around the air filter, it is no big deal to devise
a warm air door into the engine compartment.
FWIW,
Best regards,
--
Gilles
http://contrails.free.fr
Message 2
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| Subject: | Re: rotax 912 over-run experience |
Its called over speed .
Above 6100 and with good oil pressure there is a good chance you have had valve
to piston contact.
Compression check and lift all the cylinder heads. Inlet valves and pushrods are
not cheap.
Why do you over speed? The limits are not there for you to pick and choose when
you follow them!
--------
Austria .............
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=227465#227465
Message 3
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| Subject: | Re: rotax 912 over-run experience |
RPM over 5800 can cause valve float where the cylinder valve springs are
basically not strong enough to keep up with the high frequency. Then
you can get the valves smashed up and the piston deformed and lifters
crushed.
If you value your aircraft, why don't you believe the owner's manual for
the engine.
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=227488#227488
Message 4
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| Subject: | Re: rotax 912 over-run experience |
Hi Nicola,
You most likely have damaged a valve seat, lifter or bent a rod. It needs to have
the heads pulled to inspect the valve seats, lifters and pull the rods to look
to see if they are straight. Don't just leave this and keep flying as you
will incur further damage.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Service Center
520-574-1080
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=227491#227491
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