Today's Message Index:
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1. 05:46 AM - news letter (Tex Mantell)
2. 06:37 AM - Leanable mixture control for jabiru engine. (flylightning)
3. 11:43 AM - Re: Leanable mixture control for jabiru engine. (Johnny Thompson)
Message 1
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I really enjoy the newsletter and last month was about test flying your
plane. I was hoping that Buz or maybe Nick will do something on how to
correct certain trim problems that could come up on the first few
flights.
Tex
Message 2
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Subject: | Leanable mixture control for jabiru engine. |
Group,
We recently got a chance to play with the HacMan mixture control system from
Green Sky Adventures. This allows manual mixture control of the bing carb on
the 3300, or any bing for that matter. The unit consist of a valve body with
adjustable knob, some plastic line and various barb fitting. It takes vacuum
pressure from the vacuum port on the bottom of the carb thru an adjustable
valve into the balance tube from the carb to airbox. The balance tube from
the airbox to the carb allows the pressure in the carb to be at the same
air-pressure as in the air coming into the carb. If you can change the
pressure in the carb bowl you can change the mixture, this is evident if
anyone has forgot to hook up the balance line, the carb runs very rich. Long
story short using this valve you can introduce a vacuum into the bowl to
make it harder for the venture effect to pull fuel out of the bowl. With the
knob all the way in the bing works as it normally does.
Bill bought this from N197RW, his recently completed Lighting here in SYI.
Yesterday I did a test flight. Leveled off at 3,500 msl with a DA of 5,000.
Set 2850 and flew around for 5 minutes to let all stabilize with the control
full rich, or normal bing operation in this case. My EGT's were around 1300
degrees. I turned the knob out a turn or so and the egts with in about 30
seconds came up to 1350, I than fine tuned it to get about 1375 or so,
worked perfectly. To make sure it wasn't a joke I turned it back in and the
egts all dropped back down to 1300. So up I went to 9000msl and a DA of
about 11500. set 2850 for about 5 min. The egts up there were about
1230-1250. I turned the knob out the same and got them up to 1300, so out a
little further and I was able to tune for about 1350-1375...impressed.
turned it in and all went back to 1250 or so. This thing really does work.
The fuel flow is not calibrated in the plane so the numbers are not needed
but the fuel flow did go down as the system was "leaned".
I will have to say that at WOT in climbs the system does not do a lot. I
think the venturi in the carb is too much for the amount of vacuum you can
introduce to compensate. It will lean about 50 degrees or so at WOT. So I
would say get the main jet set right for WOT and than get the needle jet for
cruise close.
This thing really works in cruise and that is where you need it. I think I
will be getting one to have in our lightning.
Nick Otterback
Arion Aircraft, LLC
Message 3
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Subject: | Re: Leanable mixture control for jabiru engine. |
Hi Nick
Sounds good. Which kit is installed on the Lightning? Does the 4'
length work of do you order longer? What jets were you using?
Thanks. Ready to order today. Johnny
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