Paul,
You don't know perhaps that I was so lucky to find an Europa builder in my
village at ten minutes walking, without knowing him before I came back from
Kirbymoorside with the first Kit stage. Second convenience was that we
choose the same configuration. Mono XS, Rotax 912 ULS, Airmaster CS etc...
My friend was already one year building and afterwards he said he was making
the rough copy for me. So I was witness of the cooling problems he had
before I was that far and so I made several decisions from the beginning.
If you are aware of the fact that under the cowling airflow is submitted to
the same aerodynamic flow rules as anywhere than you may consider the
cowling design as very poor.
First came the fish mouth opening. By bringing the entrance farther from the
center of the propeller you can benefit of a greather prop wash.
Second object were the radiators. The cubic block radiator for the coolant
even with the gap underneath filled up wasn't a technical tour de force. I
used a radiator with the same contents but half as thick to fill up the
disponible section. The oil radiator stayed on its original place but
received a thermostatic valve.
The exhaust system was keracoated in order to exchange less heath under the
cowling.
Finally after studying the shape of the air entrance (courtesy to Gilles
Thesee and others) I decided to make a kind of pitot tube profile where the
smallest section was half the area of the radiator surface. Only outside air
is passing trough the radiators.
Once you have sufficient air entering all the openings in the cowling, you
also must work on the excit. Here Terry Seaver learnt me a lot to guide the
air out and by trial and error I made the final shape after measuring
temperatures on different places under the cowling. Therefor I used the
epoxy and cloth that I had reinforced by a layer of carbon/kevlar. No
particular reason for the radiuses; let's call it personal styling.
The results are as follows: Normal temperatures for coolant (Evans) 110C at
sea level and 95 for oil. Note that the oil is not cooled only by the
radiator but also by the crankcase and the reservoir, this latter placed
behind the naca scoop. In hot summer 40C the temperatures will raise up to
120C for the coolant and 105C for the oil while taxiing and in TO on full
power and climbing. Even though this is temporarily until reaching cruise
level. If at greater altitudes the coolant will slow down a bit, the oil
stays on 90C due to the thermostatic action.
Now it is difficult to say: copy my installation and you will have the same
results. With the 914 you have a different configuration and therefore I
have no experience.
I wish you good experimental building,
Karel Vranken #447 F-PKRL 203 hours.
PS I am revalidating from a surgical intervention at the right shoulder. At
a better moment I will send you some more pic's.
----- Original Message -----
From: "Paul McAllister" <paul.the.aviator@gmail.com>
Sent: Tuesday, January 20, 2009 3:36 AM
Subject: Re: Europa-List: A question on composits
> <paul.the.aviator@gmail.com>
>
> Hi Karel,
>
> I was wondering now that you have put a little more time on your
> airplane are you still happy with your modification? Also, I am
> curious about a few other things.
>
> - Did you do this modification from the beginning, or after you had
> been flying for a while. If yes, do you have any before / after
> comparisons to share.
> - How do you find this modification works on during a long taxi on a
> hot summers day.
> - Is the size of the inlet the same or smaller than the original
> Europa design. If smaller, can you give me your new square area ?
> - It looks like your new inlet does not project as far forward as the
> original Europa design, can you give me some measurements.
> - Did you make your modification using Epoxy or vinyl-ester resin ?
> - Is there any particular reason that you did not make large radius's
> on the edges of the inlet.
>
> I have two problems to solve, mine over heats if I have a long taxi
> (CHT), or if Tower has me standing at the hold short line too long.
> The other issue is that the aircraft (914) is capable to climb at more
> that 1000 feet per minute all the way to 10,000 ~ 12,000', however the
> oil overheats if I do more that 500' per minute.
>
> If you have any more photos other that the 3 you shared on the forum,
> I'd appreciate it if you could send them on.
>
> Thanks for indulging my long list of questions.
>
> Regards, Paul
>
>
> On Thu, Jul 3, 2008 at 3:28 PM, karelvranken <karelvranken@hotmail.com>
> wrote:
>> Jeff,
>> In attachment my concept of cowling and inner radiator duct.
>> Best regards,
>> Karel Vranken
>
>
>
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