Hello Graham,
Frans has attempted this with his design, but for a mono wheel there is a
very real chance of CO entering the airplane through the tunnel.
Exhaust augmentation / extraction makes a whole range of issues go away.
Ground cooling gets better the faster the engine runs, and as I understand
it from the Long EZ guys, you no longer need to diffuse the inlet airstream
.
Alas, I am with Bud on this.... time for tinkering is long over. I would
guess with research and building that Frans and I have spent many hundreds
of hours and its time to go flying :)
Cheers, Paul
On Sat, Jun 23, 2012 at 5:44 AM, GRAHAM SINGLETON <
grahamsingleton@btinternet.com> wrote:
> Paul
> you know I can't resist temptation! I suspect that a bit of work re
> exdhaust extraction might
> be profitable, it seems to work well on Long EZs, hoping to verify with
> flight testing in the next month.
> Graham
>
> ------------------------------
> *From:* Paul McAllister <paul.the.aviator@gmail.com>
> *To:* europa-list@matronics.com
> *Sent:* Wednesday, 20 June 2012, 17:32
>
> *Subject:* Re: Europa-List: Re: Contact detail & Help
>
> Ha ha.... I wondered who was going to be first out of the closet, me or
> Fran=92s. Fran=92s and I have been collaborating on a journey of discove
ry for
> the last couple of years.
> I have been reluctant to share what I have been doing, mostly because up
> until now I have only been able to tell everyone what doesn't work! Both
> Fran's and I can share funny stories of tuft test showing air flow out
> where it should be flowing in, some take offs where we couldn't get back
on
> the ground quick enough due overheating and lots of work and re work.
> For me, I am still works in progress, but over the next winter I plan on
a
> fourth iteration over next winter which will be a similar design to Fran
=92s.
> If I can persuade my friend Graham Singleton to come and visit, it might
> even a new carbon fiber cowling :)
>
>
> At a high level the sources of design material we used were:
>
> - Kays & London wedge diffuser
> - Kuchemann & Weber trumpet diffuser
> - Cooling design notes from the Central States Canard Group
> - Taper diffuser design from the Canard group
> - Oil Streaking presentations from the Central States Canard
> Group
> - Think Vs. think radiator notes from Rotary Engine forums.
> - Cooling Vs flow data from Rotax and Laminova
>
>
> Our design criteria was:
> Cooling that works in all phases of operation:
>
> - Ground
> - Climb
> - Cruise
>
> Operates over a range of -5c to 40c
> Offers the lowest drag possible
>
> This ultimately dictated a few design solutions:
> *
> *
> *Cowl Flap. *
> This is the only way we could get cooling over a large speed range and
> ambient temperature.
>
> *Laminova liquid oil heat exchanger.*
> In one of the design iterations that Fran's had created he had the oil an
d
> water radiators separated. Although this provided plenty of oil and liqui
d
> cooling it caused a long cycle time to bring the oil temperature up to
> operating temperature. The Laminova solves this problem. One problem tha
t
> Fran's and I have not been able to solve is the need for a small axillary
> oil radiator.
>
> *Thick Vs. Thin Radiators.*
> I was ultimately able to make the thick radiator work with a Kuchemann &
> Weber trumpet diffuser, but I intend to abandon this. From our research w
e
> have discovered that 70 to 80% of the heat exchange occurs in the first
> 20mm of the radiator.
>
> *Diffused Inlets.*
> At first glance Fran's cowl appears to have no diffuser on the inlet side
> of the radiator, however it works very well. After reading the design
> notes for the Kays & London wedge diffuser our hypothesis is that because
> the coolant radiator is at an angle to the relative wind it behaves like
a
> wedge diffusers.
>
> *Other thoughts & observations.*
> Fran=92s has been flying a working solution for nearly a year and his des
ign
> can be used as is. I am doing some experimentation with a single diffuse
d
> inlet that provides the engine combustion air, inter cooler and the engin
e
> shroud. Given the level of effort this has proved to be I wouldn=92t
> recommend anyone copying what I have done, and it remains to be seen if i
t
> even works.
> Over next winter I plan on removing the thick radiator and I expect that
> this will be a lower drag configuration over what I have.
> Pointing the exhaust back is offers a lot of drag reduction. I have some
> photographs that show the exhaust plume on the old style exhaust shooting
> out nearly 2 meters. For monowheel the exhaust needs to be much longer s
o
> that carbon monoxide does not find its way into cabin via the tunnel.
> Unfortunately this was complex bit of stainless steel to fabricate.
> When my cowling is fully open it is the same angle as the standard
> cowling. I see 8 knots difference between fully open and fully closed.
> This isn't an exact comparison because when my cowl flap is open air will
> spill around the side and I expect this would be higher drag than the
> original cowl. I have done a number of long cross country trips and for
> the same manifold pressure settings I am seeing about 5 knots increase in
> my cruise. I have Warp drive blades and I do not wing root fairings so m
y
> set up is not as efficient as Fran=92s.
>
> Regards, Paul
>
> *http://www.matronics.com/Navigator?_blank"; href="http://forums.matroni
cs.com/">http://forums.matronics.com
>
>
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