Today's Message Index:
----------------------
1. 07:02 AM - Re: Re: 912UL Initial Engine Test Run (PWilson)
2. 07:27 AM - Re: 912UL Initial Engine Test Run (PWilson)
3. 07:27 AM - Re: R912UL Initial Engine Test Run (PWilson)
4. 08:12 AM - Re: Re: R912UL Initial Engine Test Run (B Johnson)
Message 1
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| Subject: | RE: 912UL Initial Engine Test Run |
--> RotaxEngines-List message posted by: PWilson <pwmac@sisna.com>
Normal procedure when a system has no high point
bleed or when one suspects an air pocket, which
is 100% of the time for me. Any mechanic would do
this for brakes, power steering and coolant.
Based on experience some engine coolant systems
do not need it. In the case of the Rotax I would
do it just to be sure. Any engine has air pockets
after the first fill and some will self purge.
Harbor Freight has a cheap hand operated vac
pump. Get a rubber stopper from the hardware
store drill a hole and put it in the filler and
start sucking. Do this until the vacuum holds
steady. You might have to get another pressure
cap and drill a hole in it to get a proper seal.
Study the coolant pipes to see what you have done
that may have caused a place where the bubble
could form. But, who cares just bleed it to be sure.
At 05:27 PM 9/4/2006, you wrote:
>--> RotaxEngines-List message posted by: "Hugh
>McKay III" <hgmckay@bellsouth.net>
>
>Paul:
>
>I did not bleed air out of the system. I did not know I had too! There is no
>information in the Rotax operators manual addressing cooling system "air
>pockets"! This is all news to me! Where is this "air pocket" supposed to
>form, and where and how do you remove it with a "hand held" vacuum pump?
>
>Hugh
>
>-----Original Message-----
>From: owner-rotaxengines-list-server@matronics.com
>[mailto:owner-rotaxengines-list-server@matronics.com]On Behalf Of PWilson
>Sent: Monday, September 04, 2006 5:59 PM
>To: rotaxengines-list@matronics.com
>Subject: RotaxEngines-List: RE: 912UL Initial Engine Test Run
>
>--> RotaxEngines-List message posted by: PWilson <pwmac@sisna.com>
>
>Hugh,
>I have not followed closely. What steps did you
>take to bleed the air out of the coolant system?
>Its pretty common to have a big air pocket that
>is difficult to dislodge. If there is a pocket of
>air then overflow after shutdown would be
>expected as would excessive temps. I usually use
>a hand held vacuum pump for a bleed task.
>
>BTW, I would recommend spending the extra $$ and
>put in the proper coolant. This will elevate the
>boiling point and the max allowable temp. The
>Rotax bulletin tells you which formulation to
>buy. A side benefit would be the low pressure in
>the system achieved with the new low pressure cap
>Rotax cap. This will allow longer life for the
>various coolant system seals. The only drawback is cost of coolant.
>Regards, Paul
>================
>At 04:17 PM 9/4/2006, you wrote:
> >--> RotaxEngines-List message posted by: "Hugh
> >McKay III" <hgmckay@bellsouth.net>
> >
> >Thom/Gilles:
> >
> >I have followed your dialogue with great interest, and it has helped me
> >immensely. I have no experience with this engine, so I was alarmed when I
> >saw the CHT continuing to rise. I was even more alarmed when I shut down,
> >and heard the coolant boiling in the overflow bottle. I still don't know
>why
> >this happened. There is no question that the engine was not being cooled
> >properly, the question is why? It may have been a combination of existing
> >circumstances (i.e. static engine run, no horizontal movement of plane,
> >tarmac temp 88 degrees+, engine fully cowled with spinner, horizontal
> >radiator, and length of operation). I do know that with the spinner on, the
> >91/2 inch diameter spinner flange eats up most of the free area for air to
> >enter the engine compartment. In fact there is only 18 square inches of
>free
> >opening left for air to enter the engine compartment. This may be fine with
> >the plane traveling at, say 90 mph, but maybe not with the plane sitting on
> >the ground for 10 to 15 minutes in 88 F. I don't know, but certainly I
> >would think the plane designers would design for this condition. What free
> >opening does Rotax require on fully cowled engines?
> >
> >Since this was the initial engine start, I am going to call Lockwood Green
> >tomorrow and explain every thing that happened to them and get their
> >opinion. I'll keep both of you informed as to what they say. Again, thank
> >you for your advice, counsel, experience, and knowledge.
> >
> >Hugh
> >
> >
> >-----Original Message-----
> >From: owner-rotaxengines-list-server@matronics.com
> >[mailto:owner-rotaxengines-list-server@matronics.com]On Behalf Of Gilles
> >Thesee
> >Sent: Monday, September 04, 2006 4:30 PM
> >To: rotaxengines-list@matronics.com
> >Subject: Re: RotaxEngines-List: Re: Allegro 2000, 912UL Initial Engine Test
> >Run
> >
> >--> RotaxEngines-List message posted by: Gilles Thesee
> ><Gilles.Thesee@ac-grenoble.fr>
> >
> >Hi Thom,
> >
> > > I think we are in general agreement and the discussion has been of value
> >to anyone who cares, or at least I hope so.
> > >
> >
> >Agreed.
> >Rotax engines are very tough. I don't think Hugh's engine was damaged,
> >though I tend to treat my own engine more kindly ;-)
> >Nice discussion.
> >
> >Best regards,
> >Gilles
> >http://contrails.free.fr
> >
> >
> >
> >
> >
> >
>
>
Message 2
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| Subject: | RE: 912UL Initial Engine Test Run |
--> RotaxEngines-List message posted by: PWilson <pwmac@sisna.com>
Hugh,
I cannot remember how many auto shop manuals I have used that give
instructions on bleeding the air out of a coolant system when
starting with a dry engine. Some engines even had a bleed valve some
has a high point fitting. Lately on newer cars the instructions are
missing . Which probably means they are self bleeding due to better
design. That may be the case for the 912, but better to be safe than sorry.
Paul
Message 3
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| Subject: | RE: R912UL Initial Engine Test Run |
--> RotaxEngines-List message posted by: PWilson <pwmac@sisna.com>
True, the engine theoretically should run a hotter due to properties
that conduct heat less the water or 50/50 EG.
Insulating the fuel lines will capture the heat and make vapor lock
worse. All insulation does is slow the heat transfer process - wont
make the lines cooler. Better to figure out how to get some cool air
to them or re route them to a cooler place. A pretty easy thing to
solve, but for a static test there is more heat due to the plane not flying.
Rotax has specifically specified a formulation for the Evans that is
compatible with their coolant flow and pump, so the engine should be
OK. Did you see a 30 deg F rise in oil temp? IMO, A pretty big increase.
Paul
================
At 10:32 PM 9/4/2006, you wrote:
>--> RotaxEngines-List message posted by: "B Johnson" <bjohnson@satx.rr.com>
>
>Beware of using the evans coolant in a system (aircraft) not specifically
>designed for it. I ended up in a baaaad situation with vapor lock (with
>100LL!!! And insulated fuel lines) after switching to evans. Evans, while
>not boiling until well over 300F, also does not cool as well. You WILL see
>at least 30F increase in normal operating temps with the evans coolant.
>
>-Bruce
>
> > -----Original Message-----
> > From: owner-rotaxengines-list-server@matronics.com [mailto:owner-
> > rotaxengines-list-server@matronics.com] On Behalf Of PWilson
> > Sent: Monday, September 04, 2006 5:59 PM
> > To: rotaxengines-list@matronics.com
> > Subject: RotaxEngines-List: RE: 912UL Initial Engine Test Run
> >
> > --> RotaxEngines-List message posted by: PWilson <pwmac@sisna.com>
> >
> > Hugh,
> > I have not followed closely. What steps did you
> > take to bleed the air out of the coolant system?
> > Its pretty common to have a big air pocket that
> > is difficult to dislodge. If there is a pocket of
> > air then overflow after shutdown would be
> > expected as would excessive temps. I usually use
> > a hand held vacuum pump for a bleed task.
> >
> > BTW, I would recommend spending the extra $$ and
> > put in the proper coolant. This will elevate the
> > boiling point and the max allowable temp. The
> > Rotax bulletin tells you which formulation to
> > buy. A side benefit would be the low pressure in
> > the system achieved with the new low pressure cap
> > Rotax cap. This will allow longer life for the
> > various coolant system seals. The only drawback is cost of coolant.
> > Regards, Paul
> >
>
>--
>
>
Message 4
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| Subject: | RE: R912UL Initial Engine Test Run |
--> RotaxEngines-List message posted by: "B Johnson" <bjohnson@satx.rr.com>
> -----Original Message-----
> From: owner-rotaxengines-list-server@matronics.com [mailto:owner-
> rotaxengines-list-server@matronics.com] On Behalf Of PWilson
> Sent: Tuesday, September 05, 2006 9:07 AM
> To: rotaxengines-list@matronics.com
> Subject: RotaxEngines-List: RE: R912UL Initial Engine Test Run
>
> --> RotaxEngines-List message posted by: PWilson <pwmac@sisna.com>
>
> True, the engine theoretically should run a hotter due to properties
> that conduct heat less the water or 50/50 EG.
> Insulating the fuel lines will capture the heat and make vapor lock
> worse. All insulation does is slow the heat transfer process - wont
> make the lines cooler. Better to figure out how to get some cool air
> to them or re route them to a cooler place. A pretty easy thing to
> solve, but for a static test there is more heat due to the plane not
> flying.
> Rotax has specifically specified a formulation for the Evans that is
> compatible with their coolant flow and pump, so the engine should be
> OK. Did you see a 30 deg F rise in oil temp? IMO, A pretty big increase.
> Paul
Yes..... This was the expected behavior though, based on listening to the
ultraflight radio spot on the subject.... Again, the heads were still well
within the 300f limit (about 265-270 on climbout on a hot day) and the oil
stayed under 250 (JUST under 250F). Then trying to leave Prescott on a hot
afternoon, intermittent vapor lock reared it's ugly head... as we tried to
climb out, we got some slight missing, then more, then landed to check it
out... tried to take off again (runup to ~4200 was ok) but at about 4300 on
rollout-bad stumbling, a change on the ramp back to 60/40 auto coolant, and
no more problems. (This was a 912s)
-Bruce
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