Today's Message Index:
----------------------
1. 03:14 PM - Re: Lightning Elevator flutter (robert keen)
2. 04:48 PM - hackman mixture unit (Tex Mantell)
3. 07:05 PM - Re: hackman mixture unit (Bill Strahan)
4. 07:14 PM - Re: Lightning Elevator flutter (Bill Strahan)
5. 08:12 PM - Re: Lightning Elevator flutter (N1BZRich@AOL.COM)
Message 1
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Subject: | Lightning Elevator flutter |
Nick,
I have experienced elevator flutter twice at around 140 knots indicated. I
was told by the Australian agent Dennis, that it would be a loose tape under
the wing.
I have not yet retaped the wing joint yet, but I would like the Mass Balance
figures so I can check the elevator myself.
Can you send me the info please? I will keep you posted on what I find.
Also do you have the mass balance figures for the ailerons?
Should the Lightning have bungie cords on the elevator pushrod to hold some
weight?
Thanks Smokey.
From: owner-lightning-list-server@matronics.com
[mailto:owner-lightning-list-server@matronics.com] On Behalf Of flylightning
Sent: Thursday, 5 August 2010 11:06 PM
Subject: RE: Lightning-List: Lightning Elevator flutter
No. Did you experience this or just simply asking?
The prototype was mass balanced at first but when looking at light sport and
saving weight we removed the balances and retested. There was no evidence of
flutter.
We dive test every LSA Lightning to Vne, 180knts IAS ( 208mph) with proper
attempts to induce flutter with no issues. It is required by the ASTM on
every aircraft.
Nick Otterback
Arion Aircraft, LLC
_____
From: owner-lightning-list-server@matronics.com
[mailto:owner-lightning-list-server@matronics.com] On Behalf Of robert keen
Sent: Thursday, August 05, 2010 3:06 AM
Subject: Lightning-List: Lightning Elevator flutter
Has anyone had a problem with elevator flutter? Can anyone tell me the mass
balance limits of the lightning control surfaces?
Thanks Smokey
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18:25:00
Message 2
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Subject: | hackman mixture unit |
I have recently installed the Hackman Mixture control in my Lightning
and it seems to work as advertized. At cruse at altitude its save about
a half gallon an hour as indicated by the flow meter. I would like to
know who else is using this device and what experiences, precautions,
etc. that others have found. Thanks TEX
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Subject: | Re: hackman mixture unit |
I love it as well, but it does work differently from a conventional mixture control
on a lycoming/continental.
By that, I mean it is dependent on power setting. In a lycoming, if you are properly
leaned at altitude you can make power changes and the engine will continue
to run. Not so the Jabiru/Hacman combo.
If you increase the power you will immediately be running too rich. If you decrease
it, too lean. Decrease it too much and the engine stops.
There were a few times that I leaned at a low altitude when I first had the unit,
then forgot about it in the pattern because I was not used to having the mixture
control as part of my landing checklist. When I reduced the power on downwind
the engine quit!
I'm embarassed to say I performed this self-induced increase in blood pressure
a second time before I finally integrated the use of the control.
So don't forget it's there, and if you pull back the power at altitude for any
reason, don't be shocked if the engine wants to quit. I've done that a time or
two as well, just pulled back the power quickly when encountering some heavy
turbulence and it caught me off guard when the engine started stumbling.
I'm going to take my younger daughter to L.A. tomorrow for some father/daughter
time. I'll take the O2 and will come back at 15-17k weather permitting. Who
knows, maybe tailwilnds and Hacman will let me fly nonstop back to Dallas. :)
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=307991#307991
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Subject: | Re: Lightning Elevator flutter |
Perhaps I'm poorly educated on the subject, but I thought in most cases of control
flutter the time between onset and airframe failure was less than it takes
to say "hey what is that?"
I'm sure it's possible to have an episode of flutter, and even more likely to have
some buzz that would precede flutter, and live to tell about it, but it seems
very unlikely.
When I was testing 7RW I eventually worked my way to 200knots true with autopilot
off and hands off the controls so the inertia of the system was as little as
it could be. I did stick slaps at 190knots true and saw the system return to
equilibrium at the same rate it had at every other speed up until that point.
That was enough to make me feel okay with the speeds at which I would be operating.
I hope that the results of this inquiry are shared on the list. I'm not concerned
for 7RW but would like to find out what is learned in this situation.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=307994#307994
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Subject: | Re: Lightning Elevator flutter |
Hi Smokey,
I don't want to totally disagree with your flutter assessment, but I
kind of doubt that what you felt was true elevator flutter. Here is why -
Many other Lightning builders, during the 40 hour phase one test period, have
flown their Lightnings to Vne without any hint of flutter. And in the
case of the prototype, Nick and I have flown it to well beyond the published
Vne in several different stabilizer/elevator configurations. First, with
the full aerodynamic and dynamic counter balance, they with a lesser modified
configuration (not as large an aerodynamic counterbalance), and finally
with no aerodynamic counter balance at all. In each case, absolutely no
flutter, or to be more specific not even any indication of flutter. So if your
airplane is having a problem, something may be different about your
airplane. But lets not totally rule it out yet until we know more from you.
So can you give us some more information to go on? For example, you
said it happened twice at about 140 knots indicated. Was that the first two
times you had your Lighting to 140 knots? Or has it been beyond that
before with no problems on other occasions? When it happened, what did you
feel (or see) to make you think elevator flutter? Was the stick moving? If
so, could you freeze the stick with hand pressure? What did you do to case
what ever was happening to stop happening? Did it stop immediately whey
you did that? How much flying time on your airplane? Have you checked the
elevator control system to see if there is excess slop in the system? Is
anything looser now than before? I have seen at least one case where some rod
end bearings developed some slop and the extra slop did cause some minor
aileron buzz but no real buffet. Do you have the modification with the
elevator trim tab? If so has that tab been there all along? And if so, how is
the hinge for the tab? Has it loosened up? Sorry for all the questions,
but these kind of things will help diagnose the problem and come up with a
fix.
As Dennis hinted at, with no tape between the wing and the fuselage
karman, you will probably have a higher stall speed and some strange buffet
feelings, but it is not flutter. So you might want to check that area.
Other than the above, I can offer no other suggestions until we hear
more from you. Nick will certainly jump in here when he see this on Monday
morning. Rest assured that the Lightning is one of the more thoroughly
tested designs out there. It is way stronger and thus safer than it has to
be, but that is the basic design philosophy that Arion goes by - better than
the others.
I look forward to hearing from you.
Blue Skies,
Buz
In a message dated 8/8/2010 6:15:48 P.M. Eastern Daylight Time,
smokeysmail@bigpond.com writes:
Nick,
I have experienced elevator flutter twice at around 140 knots indicated.
I was told by the Australian agent Dennis, that it would be a loose tape
under the wing.
I have not yet retaped the wing joint yet, but I would like the Mass
Balance figures so I can check the elevator myself.
Can you send me the info please? I will keep you posted on what I find.
Also do you have the mass balance figures for the ailerons?
Should the Lightning have bungie cords on the elevator pushrod to hold
some weight?
Thanks Smokey.
From: owner-lightning-list-server@matronics.com
[mailto:owner-lightning-list-server@matronics.com] On Behalf Of flylightning
Sent: Thursday, 5 August 2010 11:06 PM
Subject: RE: Lightning-List: Lightning Elevator flutter
No. Did you experience this or just simply asking?
The prototype was mass balanced at first but when looking at light sport
and saving weight we removed the balances and retested. There was no
evidence of flutter.
We dive test every LSA Lightning to Vne, 180knts IAS ( 208mph) with proper
attempts to induce flutter with no issues. It is required by the ASTM on
every aircraft.
Nick Otterback
Arion Aircraft, LLC
____________________________________
From: owner-lightning-list-server@matronics.com
[mailto:owner-lightning-list-server@matronics.com] On Behalf Of robert keen
Sent: Thursday, August 05, 2010 3:06 AM
Subject: Lightning-List: Lightning Elevator flutter
Has anyone had a problem with elevator flutter? Can anyone tell me the
mass balance limits of the lightning control surfaces?
Thanks Smokey
http://www.matronics.com/Navigator?Lightning-List
http://forums.matronics.com
http://www.matronics.com/contribution
http://www.matronics.com/Navigator?Lightning-List
http://forums.matronics.com
http://www.matronics.com/contribution
Internal Checked by AVG - www.avg.com
18:25:00
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