Today's Message Index:
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1. 01:07 AM - Re: more prop test info (James, Clive R)
2. 04:56 AM - ompletion rates (EAFerguson@aol.com)
3. 02:54 PM - Angle of incidence Plates (flylightning)
Message 1
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Subject: | more prop test info |
The other bit which hasn't been mentioned is flex of the blade which
creates an effective pitch change.
This could be even more effective (or not) with a carbon prop. If you've
ever flown alongside a carbon prop'd plane you can see the bend in the
blades, coned forward.
Manufacturers try to harness this flex/twist effect when the prop is
loaded to give an optimum pitch at different speeds and loads.
The Sens I have on my Jabiru doesn't have a covering, they told me if I
have the covering the prop needs to be 2" coarser pitch as the covering
stiffens it up and dynamically the effective pitch will change (be
finer).
Part of the 1/4 of black magic I suppose.
Either way Dave's plane seems to be banging along nicely!
Regards, Clive
-----Original Message-----
From: owner-lightning-list-server@matronics.com
[mailto:owner-lightning-list-server@matronics.com] On Behalf Of Brian
Whittingham
Sent: 11 August 2009 05:19
Subject: RE: Lightning-List: more prop test info
We've discussed similar topics to this a few times before, but when I
flew the Lightning, I had the same experiences. Never could get as high
RPM at WOT with the ground adjustable. My thoughts are that you have a
couple of different things that are readily identifiable differences
between the props. (and the only two that I can think of off the top of
my head) First is the mass of the entire unit, hub and all. I think
that cuts down on the RPM at WOT. The other is your medium. Wood tends
to flex more, especially at the tips than the carbon fiber. Props are
definitely not my specialty though. We were always taught in school
that prop design was about 1/4 aerodynamics, 1/4 pure luck, 1/4 theory,
and 1/4 black magic. Not only is there a difference in pitch at various
stations along the blade, you'll notice a difference in a lot of the
newer designs in having raked tips. This so called scimitar blade helps
with noise as well as keeping the blade more effective at higher tip
speeds. Always interested in hearing prop info test data. Keep it
coming folks. Brian W.
________________________________
From: N1BZRich@aol.com
Subject: Re: Lightning-List: more prop test info
In a message dated 8/10/2009 11:52:46 A.M. Eastern Daylight Time,
corky@hbci.com writes:
MY static was 2560 rpm. valves set 12 hrs ago, compression is
great, gaps set. BUZ--
Dave,
I have never seen the need to do a WOT static run up, but rather
look for the rpm on takeoff roll and perhaps more importantly, the rpm
when climbing out. For example, my rpm when climbing out at 100 mph
indicated is 2760 to 2780. That is pretty near the power curve for the
3300. When near max gross (which is 1320 for N31BZ) I have never seen a
take off roll longer than 700 to 800 feet even when at high density
altitude and high temperatures. For example the temp today when I
started takeoff roll was 96 degrees. My gross weight was about 1200
pounds and my take off roll was right at 600 feet. Yes, I am pretty
near sea level but DA was over 2000'. Hope all this helps.
One other thought - of all the Sensenich ground adjustable carbon
fiber props I have tried, I have never found one to be as smooth running
at a wooded Sensenich. I have even weighed the individual blades to
make sure they were the same weight. Also, I always set the pitch by
using a prop protractor on each blade instead of the index on the hub.
That seemed to make them run a little smoother, but still never as
smooth as their wooded props. The other thing about the ground
adjustable, for some reason, even when set at exactly the same pitch as
a wooded ZK, they have never been as fast at the higher rpms, and that
has been most noticeable when above the 150 mph tas speed range. Not
sure what was going on, but the wooded prop would always be as much as 8
mph faster at the same rpm. And at WOT the carbon fiber prop would
never turn up as high an rpm. Remember they were both the same pitch,
same diameter and same ZK blade profile. Of course the prop I am
running now (and the one you are currently testing) is a FK blade
profile. The main difference as I understand it is the FK is a blended
profile with slightly different pitches at the tip, the mid blade and
near the hub. Tip is different for noise, mid blade for pull, and near
the hub for more cooling air into the intakes. Seems like a great idea
to me.
Buz
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Message 2
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In a message dated 8/10/2009 3:14:36 P.M. Eastern Daylight Time,
mark@flylightning.net writes:
Another interesting statistic is that all of the flying Lightnings have
been
completed by the original owners. The national average is somewhere around
25% and ours is 100%!
Now that's impressive!
Earl
**************A Good Credit Score is 700 or Above. See yours in just 2 easy
steps!
=JulystepsfooterNO115)
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Subject: | Angle of incidence Plates |
To group,
It has come to my attention by a builder that the Build manual does not
include instruction for the proper installation, or installation at all of
the Angle of incidence plates.
I believe that everyone who is flying their Lightning has installed these
plates and any one in close contact with there dealer knows about them and
has installed them.
I the kit should be 4 plates which should look like thick steel plate
washers with AN-5 buts welded to them. These are to be installed inside the
forward and rear attach points of the wing.
When setting the wing incidence you are told to match drill the forward and
rear hard points on the wings to the pre-drilled holes in the fuselage with
a 5/16" bit.
The holes in the wings must than have a AOI plate installed on the inside of
the wing not the side which mates to the fuselage.
The plate should be attached with #8 screws and nuts or with stainless steel
1/8" rivets of sufficient grip length. 2 of one or the other per plate will
be enough, think of them as giant nut plates, the screws or rivets are to
just keep them from turning and are not structural.
I will be updating the Spar box and wing alignment section tomorrow to
include these instructions.
Nick Otterback
Arion Aircraft, LLC
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