Today's Message Index:
----------------------
1. 01:55 AM - Re: more prop test info (selwyn)
2. 06:17 AM - Re: Re: more prop test info (Pete Krotje)
3. 08:54 AM - Re: more prop test info (jeynon)
4. 12:04 PM - Re: Re: more prop test info (Bob Haas)
5. 12:17 PM - Re: Re: more prop test info (Bob Haas)
6. 05:23 PM - Re: more prop test info (selwyn)
7. 06:54 PM - Electronic Cabin Heat Vent (Jim Langley)
Message 1
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Subject: | Re: more prop test info |
Hi Buz,
I'll be interested to see that as I am sure will others. There is a school of
thought going around which says that the coarser pitch props are too coarse and
the engine is running at too high a manifold pressure for the revs. One consequence
of that would be that the thing is running on lean mixture at high power
settings, not necessarily a good thing. I appreciate you can't actually do
much about it with a fixed pitch prop (except change the prop ) but it would
be nice to know so we could operate the thing in the best way available.
Of course, if we had a decent carby with a mixture control then we would be able
to do something about it wouldn't we. That's on my list of possibles once the
warranty expires.
I'm getting towards where I can start to at least think about flying mine so I'm
keen to gather all the preliminary info possible. Another two or three months
and we may be getting close.
--------
Cheers, Selwyn
Kit 66
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=235925#235925
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Subject: | Re: more prop test info |
Actually Selwyn, more prop pitch will result in a richer mixture not leaner.
Pete
-----Original Message-----
From: owner-lightning-list-server@matronics.com
[mailto:owner-lightning-list-server@matronics.com] On Behalf Of selwyn
Sent: Tuesday, March 24, 2009 3:54 AM
Subject: Lightning-List: Re: more prop test info
Hi Buz,
I'll be interested to see that as I am sure will others. There is a school
of thought going around which says that the coarser pitch props are too
coarse and the engine is running at too high a manifold pressure for the
revs. One consequence of that would be that the thing is running on lean
mixture at high power settings, not necessarily a good thing. I appreciate
you can't actually do much about it with a fixed pitch prop (except change
the prop ) but it would be nice to know so we could operate the thing in
the best way available.
Of course, if we had a decent carby with a mixture control then we would be
able to do something about it wouldn't we. That's on my list of possibles
once the warranty expires.
I'm getting towards where I can start to at least think about flying mine so
I'm keen to gather all the preliminary info possible. Another two or three
months and we may be getting close.
--------
Cheers, Selwyn
Kit 66
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=235925#235925
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Subject: | Re: more prop test info |
So Buz, if my interpolation skills are up to par, you could shut off your fuel
altogether and cruise all day at 100 mph. [Shocked]
John Eynon
Lightning kit #53
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=235971#235971
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Subject: | Re: more prop test info |
I would like to check the manifold pressure also. I will have a manifold
pressure gage and will see just how hard my Sensenich
Ground adjustable prop is working at given airspeeds and rpm. Bob Haas
N330BH.
_____
From: owner-lightning-list-server@matronics.com
[mailto:owner-lightning-list-server@matronics.com] On Behalf Of
N1BZRich@aol.com
Sent: Monday, March 23, 2009 8:37 PM
Subject: Re: Lightning-List: Re: more prop test info
In a message dated 3/23/2009 8:05:16 P.M. Eastern Daylight Time,
selwyn@ellisworks.com.au writes:
I'd really like to see these numbers with RPM and manifold pressure
information.
OK, Selwyn, I do have manifold pressure (MP), so can eventually get that for
you. Currently I don't pay that much attention to MP (fixed pitch prop) and
I got it installed too late to be much help during the initial 40 hour test
phase. I ordered the MP set up early on, but there was a delay in getting
it to me. I wanted to use it to help with the % horse power charts, but I
was about done with the phase one testing before I got it installed. I
guess I just have been too busy to do much with it since then. But as I
said, I will get some info for you if you promise to write something up
about it and the Bing adjustments for the newsletter. Just keep bugging me
about it until I get it done.
Buz
_____
Feeling the pinch at the grocery store? Make dinner
<http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000001> for $10 or
less.
06:52:00
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Subject: | Re: more prop test info |
I concur, but if you have an adjustable prop one can manage the
engine
Some what with the Bing. Bob Haas.
-----Original Message-----
From: owner-lightning-list-server@matronics.com
[mailto:owner-lightning-list-server@matronics.com] On Behalf Of selwyn
Sent: Monday, March 23, 2009 8:03 PM
Subject: Lightning-List: Re: more prop test info
Hi Buz,
I'd really like to see these numbers with RPM and manifold pressure
information. With the Bing the only control you have over mixture is via the
airflow through the carby, set by the revs, so those numbers help to
understand what regieme the engine is operating in. The manifold
pressures help to understand this a little more.
To my mind, the fuel flow figures in isolation are very little help in
understanding what is going on in the engine and one needs an appreciation
of that to make valid propeller comparisons.
Cheers, Selwyn
--------
Cheers, Selwyn
Kit 66
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=235877#235877
Checked by AVG - www.avg.com
06:52:00
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Subject: | Re: more prop test info |
pete(at)flylightning.net wrote:
> Actually Selwyn, more prop pitch will result in a richer mixture not leaner.
>
> Pete
>
> --
Hi Pete,
Sorry, I don't follow that one.
My understanding is that what will set the mixture is a combination of throttle
opening and engine revs. Engine revs is the critical thing because it affects
the flow through the carby and thence the needle position which is what regulates
the mixture. The profile of the needle has to match the operating rev band.
>From that, if you imagine an engine with a variable pitch prop and you run it
with a wide open throttle and the thing is running somewhere near max revs, the
needle will be right out and it will be running rich mixture with most of the
needle profiles we are likely to use. If we then start winding in pitch the
revs will come back as we load the engine and somewhere a little under 3000 RPM
the mixture will start to lean off as the flow through the carby throat decreases
and the needle begins to descend. If we keep winding in pitch we will
end up at 2850 cruise revs, wide open throttle and a nice lean cruise mixture,
high manifold pressure, probably good cruise performance but an engine waiting
to go bang.
That's my theory of how the Bing works. I would be very pleased to see debate
from the experts.
--------
Cheers, Selwyn
Kit 66
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=236039#236039
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Subject: | Electronic Cabin Heat Vent |
Here's a little tidbit that I know Nick can relate to because he's a fellow
RC'r.
Instead of using the cable to control the vent for my cabin heat, I am using
a 12v-5v regulator, servo tester and Hitec Digital servo.
The servo will be mounted on the firewall, connected to the vent with a
Hangar 9 titanium control link. The servo is a standard RC digital servo
that came out of one of my big rc airplanes and has about 180lbs of torque.
This is what I had handy, although a 60-80lb servo would work fine. I built
the voltage regulator from parts and the following plans,
http://www.mybitbox.com/articles/standalone-voltage-regulator/
I also built a simple servo tester which is not much more than a 555IC, and
some cheap parts from Radio Shack with a pot to control the servo travel.
The servo will move throughout its range as fast as you turn the dial, so
you can open or close the vent pretty fast. I will be mounting the servo
tester, (heat control like on a car dash), on my center console along with
my master/EFIS switch and my flap position selector; (see my crude drawing).
The nice thing about the Hitec servos is that they are pretty robust when it
comes to heat, and are programmable for arm travel.
All in all, $59.00 for the servo and $12.00 for the rest of the parts, plus
some solder time = total of $71.00 for a digitally actuated heater vent! If
you want to go cheaper, use a HS-75BB with 100lbs of torque. It is used a
lot for robotics and only costs $29.00!
http://www.servocity.com/html/hs-75bb_retract.html What I used is over
kill, but was lying around and not being used.
I will write up something with pictures after it is installed.
Jim!
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