Today's Message Index:
----------------------
1. 02:44 AM - Re: Putting Flutter Issue to Bed (Dave)
2. 02:44 AM - Re: CH601HDS Wing Fuel Tanks (John Livsey)
3. 03:13 AM - Re: Putting Flutter Issue to Bed (Paul Mulwitz)
4. 03:37 AM - Re: Putting Flutter Issue to Bed (Thruster87)
5. 03:50 AM - Re: Putting Flutter Issue to Bed (Dave)
6. 04:25 AM - Re: Putting Flutter Issue to Bed (Paul Mulwitz)
7. 05:42 AM - Sparky and other assorted experts. (Jake Reyna)
8. 07:16 AM - Re: Putting Flutter Issue to Bed (T. Graziano)
9. 07:27 AM - Re: Sparky and other assorted experts. (dougsire)
10. 07:54 AM - Re: Putting Flutter Issue to Bed (Gary Gower)
11. 08:10 AM - Fire Extinguisher Sale (pavel569)
12. 08:48 AM - Re: Fire Extinguisher Sale (jaybannist@cs.com)
13. 08:57 AM - Re: Fire Extinguisher Sale (pavel569)
14. 09:33 AM - Re: Putting Flutter Issue to Bed (Gig Giacona)
15. 09:35 AM - Re: Fire Extinguisher Sale (Gig Giacona)
16. 11:09 AM - 601 XL tail skin (Lee Steensland)
17. 01:10 PM - Re: Re: Putting Flutter Issue to Bed (Juan Vega)
18. 01:32 PM - Re: 601 XL tail skin (Gig Giacona)
19. 01:53 PM - Re: Re: Putting Flutter Issue to Bed (Jay Maynard)
20. 01:55 PM - Re: Re: Putting Flutter Issue to Bed (T. Graziano)
21. 02:01 PM - Re: Putting Flutter Issue to Bed (Gig Giacona)
22. 02:16 PM - Re: Re: Putting Flutter Issue to Bed (Jay Maynard)
23. 02:39 PM - Re: Putting Flutter Issue to Bed (Gig Giacona)
24. 02:45 PM - Re: 601 XL tail skin (Ron Lendon)
25. 02:52 PM - Re: Putting Flutter Issue to Bed (Gig Giacona)
26. 03:23 PM - Re: Putting Flutter Issue to Bed ()
27. 03:54 PM - Re: Putting Flutter Issue to Bed (Paul Mulwitz)
28. 05:00 PM - Re: Re: Putting Flutter Issue to Bed (wade jones)
29. 06:47 PM - Re: Re: Putting Flutter Issue to Bed (Rick Lindstrom)
30. 07:34 PM - Re: Putting Flutter Issue to Bed (Juan Vega)
31. 08:00 PM - Re: Putting Flutter Issue to Bed (Gig Giacona)
32. 09:20 PM - Re: Fire Extinguisher Sale (Bryan Martin)
Message 1
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| Subject: | Re: Putting Flutter Issue to Bed |
I don't know Paul. With the engineering report in hand the NTSB may withdraw
it's request for mass balancing, it's likely to go unfulfilled at this
point. The stick issue is an undesirable feature but training could/should
address it. My hope is that the aircraft just experienced a very bad patch
of incidents and that history will not repeat itself. A new stick
arrangement would be nice, many of the Zenith designs seem to require much
more force in roll than pitch.
----- Original Message -----
From: "Paul Mulwitz" <psm@att.net>
Sent: Monday, June 01, 2009 11:31 PM
Subject: Re: Zenith-List: Putting Flutter Issue to Bed
>
> Indeed, the NTSB identified another problem - one which I think might
> explain all the accidents. It is the stick gradient problem that makes it
> easier to pull additional G's as you pull additional G's.
>
> The NTSB demanded both this be fixed and aileron mass balancing be added.
> I hope the Zenair folks are going to release design changes to resolve
> those issues. It really doesn't matter whether the changes are justified
> by German engineers or not. The changes are still needed to satisfy the
> NTSB demands.
>
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| Subject: | Re: CH601HDS Wing Fuel Tanks |
Gig,
The url (Web link) just points to my web site (camilla.homelinux.net)
where I have the picture I found a couple of years ago. So if anyone
recognises it I'm still searching.
--
Regards, John Livsey
Message 3
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| Subject: | Re: Putting Flutter Issue to Bed |
Hi Dave,
While you may be correct about the NTSB changing their position on
the design changes, I seriously doubt that will happen.
I don't think they made the demand for aileron balance based on
research about the Zodiac design. I think it was made based on the
experience in the industry that aileron balance makes safer
airplanes. According to a number of people I have contacted in this
regard, industry standard handling of this question has shown aileron
mass balancing is beneficial (i.e. saves lives) on all airplane
designs except for those that have fabric covered ailerons. Please
keep in mind that there have been a relatively high number of
structural failures on Zodiac XLs. That is why the NTSB was looking
at this particular design in the first place.
I don't know why you made the comment about the difference in forces
for aileron vs. elevator travel. That is not an issue for me or the
NTSB. The issue is the clear flaw that as you increase the G's being
pulled by the plane it becomes easier to add more G's. While
training about this flaw might prevent some deaths it seems more
appropriate to actually fix the design. I don't know exactly what
this will take, but my sense is that it is not difficult to fix. I
don't believe any pilot would apply too much force to the stick on
purpose. I think this is possible in a panic situation or possibly
as a weird mistake where the passenger accidently kicks the stick or
some such thing.
If the NTSB issues another letter saying they have decided to
withdraw their statement that these changes are needed then I will
consider dropping the same needs from my decision to ground my
plane. As it now stands, I need approved engineering changes from
Zenith or a related source for these issues before my plane gets
un-grounded. The longer it takes for Zenith to decide to create
those engineering changes the longer my plane will be grounded.
Paul
XL Grounded
At 02:41 AM 6/2/2009, you wrote:
>I don't know Paul. With the engineering report in hand the NTSB may
>withdraw it's request for mass balancing, it's likely to go
>unfulfilled at this point. The stick issue is an undesirable
>feature but training could/should address it. My hope is that the
>aircraft just experienced a very bad patch of incidents and that
>history will not repeat itself. A new stick arrangement would be
>nice, many of the Zenith designs seem to require much more force in
>roll than pitch.
Message 4
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| Subject: | Re: Putting Flutter Issue to Bed |
psm(at)att.net wrote:
> Hi Dave,
>
> While you may be correct about the NTSB changing their position on
> the design changes, I seriously doubt that will happen.
>
> I don't think they made the demand for aileron balance based on
> research about the Zodiac design. I think it was made based on the
> experience in the industry that aileron balance makes safer
> airplanes. According to a number of people I have contacted in this
> regard, i[b]ndustry standard handling of this question has shown aileron
> mass balancing is beneficial (i.e. saves lives) on all airplane
> designs except for those that have fabric covered ailerons.[/b] Please
> keep in mind that there have been a relatively high number of
> structural failures on Zodiac XLs. That is why the NTSB was looking
> at this particular design in the first place.
>
> I don't know why you made the comment about the difference in forces
> for aileron vs. elevator travel. That is not an issue for me or the
> NTSB. The issue is the clear flaw that as you increase the G's being
> pulled by the plane it becomes easier to add more G's. While
> training about this flaw might prevent some deaths it seems more
> appropriate to actually fix the design. I don't know exactly what
> this will take, but my sense is that it is not difficult to fix. I
> don't believe any pilot would apply too much force to the stick on
> purpose. I think this is possible in a panic situation or possibly
> as a weird mistake where the passenger accidently kicks the stick or
> some such thing.
>
> If the NTSB issues another letter saying they have decided to
> withdraw their statement that these changes are needed then I will
> consider dropping the same needs from my decision to ground my
> plane. As it now stands, I need approved engineering changes from
> Zenith or a related source for these issues before my plane gets
> un-grounded. The longer it takes for Zenith to decide to create
> those engineering changes the longer my plane will be grounded.
>
> Paul
> XL Grounded
>
> I just balanced the ailerons and the elevators for a DC4 which are fabric and
there are many other aircraft with mass balanced fabric covered ailerons. Cheers
>
>
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246427#246427
Message 5
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| Subject: | Re: Putting Flutter Issue to Bed |
The comment was actually in response to the stick gradient concern. It had
stuck in my mind from reading your email and my response was off target I
guess. I have thought that the stiff roll and very easy pitch was a sort of
odd arrangement, but maybe that's just something to get used to. I admire
your resolve in this matter, do you know if there are any certified light
aircraft designs with metal ailerons that do not use mass balance? I
understand that it is common practice, but surely CH is not the first to
break with tradition. My feeling is that while it is common, I would be
unlikely to want to add any structure that does not actually need to be
present.
----- Original Message -----
From: "Paul Mulwitz" <psm@att.net>
Sent: Tuesday, June 02, 2009 7:11 AM
Subject: Re: Zenith-List: Putting Flutter Issue to Bed
>
> Hi Dave,
>
> While you may be correct about the NTSB changing their position on the
> design changes, I seriously doubt that will happen.
> I don't know why you made the comment about the difference in forces for
> aileron vs. elevator travel. That is not an issue for me or the NTSB.
> The issue is the clear flaw that as you increase the G's being
Message 6
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| Subject: | Re: Putting Flutter Issue to Bed |
Hi Dave,
I don't have universal knowledge of what light aircraft designs
exist. I do know from personal experience that it is extremely
common, perhaps almost universal, that airplane designs call for
different control pressure and movement in different axes. While
this seems to be a criteria that some aviation magazine authors think
is important (i.e, "Control Harmony") I have not heard anyone suggest
there was a safety issue here.
In general, I agree with you completely that it is a bad idea to add
unnecessary features to a light plane design. If nothing else the
added weight and expense are things to avoid.
It is the question of how you define what is necessary and what is
not that makes this problem so perplexing. For me, the NTSB saying
the changes are necessary is enough. For others it is not.
I make no claim that I am right and other builders are wrong. This
is a very difficult problem to resolve, and those who believe there
is no need to fix anything have a lot of facts to support their
decision. Indeed this is not a democratic situation. We don't need
to agree or come to a consensus decision.
Building, and particularly flying, experimental airplanes is, and
will always be, a dangerous activity. Each builder and owner must
decide for himself just how much risk is acceptable. This applies
just as much for risks that are well known as for ones that are
subject to question.
My own decision was made based on my own criteria and my own
situation. I searched my soul and discussed the situation with my
wife (who also flies) and reached the conclusion I would ground my
plane, as suggested by the NTSB, until the two mentioned changes were
implemented. If I am demonstrating resolve, it is merely that there
have been no changes in the situation that would convince me I should
change my own decision.
Best regards,
Paul
XL grounded
At 03:49 AM 6/2/2009, you wrote:
>The comment was actually in response to the stick gradient concern.
>It had stuck in my mind from reading your email and my response was
>off target I guess. I have thought that the stiff roll and very easy
>pitch was a sort of odd arrangement, but maybe that's just something
>to get used to. I admire your resolve in this matter, do you know if
>there are any certified light aircraft designs with metal ailerons
>that do not use mass balance? I understand that it is common
>practice, but surely CH is not the first to break with tradition. My
>feeling is that while it is common, I would be unlikely to want to
>add any structure that does not actually need to be present.
Message 7
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| Subject: | Sparky and other assorted experts. |
Although aviation experts stressed it was much too early to speculate about the
causes of the crash, they noted that the accident was most likely caused by various
factors that combined to cause a catastrophic chain of events. (This is
in regard to the recent Airbus incident.)
They obviously haven't talked to ZBAG or the other experts on this list that don't
require data, only the belief in their reality.
A few years ago I suggested to Matt that he boot some posters, but nothing came
of it. The Zenith list has always had a small population of Flamers and/or people
I like to call Sparky. Sparky is basically a negative person and when allowed
to come into contact with those offering positive comments, he creates sparks
:-0
Here is my suggestion on dealing with Sparky. Sparky isn't relevant and exists
in a reality that requires validation. His existence depends entirely on others
acknowledging his words. The simple solution is to ignore Sparky's posts. Once
you start ignoring Sparky, his reality will crumble, his very existence will
cease to be relevant.
These are the individuals that have done the most damage to the reputation of the
XL, let's vote them off the island by ignoring them.
To test the system, start by ignoring this post :-)
Jake
do not archive
Message 8
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| Subject: | Re: Putting Flutter Issue to Bed |
"Indeed, the NTSB identified another problem - one which I think might
> explain all the accidents. It is the stick gradient problem that makes it
> easier to pull additional G's as you pull additional G's.
>
> The NTSB demanded both this be fixed and aileron mass balancing be
added."
--------------------------------------------------
Maybe I missed it (see attached extracts below from the NTSB Report) but I
do not see
where the NTSB demanded the light stick forces on the XL (also found on many
other aircraft) be "fixed", nor demanded balancing of the ailerons.
I personally believe that some if not all of the structural failures were
caused improper use of the stick, also know to be a wing removal device on
most aircraft.
Tony Graziano
XL; Jab; N493TG 495 really enjoyable hours.
----------------------------------------------------------
Recommendations extracted from the NTSB Report
Require a comprehensive evaluation of the wing and aileron system on the
Zodiac CH-601XL, including ground vibration tests, to identify design and/or
operational changes that will reduce the potential for flutter; the
evaluation should give significant consideration to the benefits of
installing mass-balanced ailerons and should also address the adequacy of
cable tension values specified by Zenair.
Evaluate the stick-force gradient of the Zodiac CH-601XL at the maximum aft
center of gravity and notify pilots of the stick-force gradient that occurs
at the aft center of gravity, especially at the higher G forces.
Potential Role of Stick Forces (Extracted from the NTSB Report)
In an effort to identify potential factors that might have contributed to
the many in-flight breakups of CH-601XL airplanes, and mindful of the fact
that high loads can cause structural failure, the Safety Board examined the
control stick forces required to generate high maneuver loads19 on the
accident airplane model. Zenair provided the Safety Board with a flight test
report that had been used to validate the airplane design under ASTM
standards. The report included data on the stick forces required to generate
maneuver loads or Gs.20 The term "stick force per G" refers to the control
force gradient that is derived from flight test data. Data from the
Comparative Aircraft Flight Efficiency Foundation's21 airplane performance
reports show that the stick force per G on other airplanes is similar to
that of the Zodiac CH-601XL except that, on
the CH-601XL, the stick-force gradient lessens distinctly as loads increase
above 2.5 Gs.22 The lessening of the gradient continues as loads surpass 4
Gs. As a result, at high Gs, a moderate increase in stick force could result
in a larger than expected increase in maneuver loads. A sufficient
stick-force gradient is required for pilots to maneuver an airplane safely.
The Safety Board recognizes that experimental and light sport airplanes
typically exhibit lighter stick forces than airplanes certified under 14 CFR
Part 23 and that, if properly trained, pilots can safely maneuver airplanes
with relatively shallow gradients. However, even experienced pilots may find
control difficult if the gradient is not constant but instead lessens as Gs
increase. With a lessening stick-force gradient, it becomes easier to
inadvertently overcontrol the airplane and reach higher acceleration forces
than intended. Zenair has expressed concern that pilots may be
overcontrolling the airplane with large or aggressive stick movements. On
May 10, 2007, the designer wrote the owners and pilots of Zodiac airplanes
an advisory letter, which included the following: The Zodiac aircraft has a
large amount of elevator control. ... Pushing the stick rapidly full forward
at cruise speed-even briefly-can result in serious damage to the airframe.
Caution must be exercised to not inadvertently push the stick rapidly to its
limits (i.e. while stretching, reaching into the rear baggage compartment,
etc.). In July 2007, the designer issued the following update: Owners should
take note that the CH-601XL has relatively light pitch control forces and
that it is possible to exceed the positive (+6) and the negative (-3)
ultimate load factors if forcing the controls in a very rough or sudden
manner. Pilots usually become familiar with the maneuvering characteristics
of an airplane while operating routinely between the 1 G and 1.5 Gs common
during normal flight. Higher G forces are often disconcerting, and a
lessening of the stick-force gradient may go unnoticed. In addition, the
stick forces are least when operating at the maximum aft center of gravity.
Although the Zodiac designer has advised pilots of the light stick forces,
the Safety Board concludes that pilots may not be aware of the change in the
effect of stick forces that occurs while maneuvering at higher Gs.
Therefore, the Safety Board believes that the FAA should evaluate the
stick-force gradient of the CH-601XL at the maximum aft center of gravity
and notify pilots of the stick-force gradient that occurs at the aft center
of gravity, especially at the higher G forces. In addition, the Safety Board
believes that the FAA should work with ASTM International to develop
requirements to be included in the standards for light sport airplanes that
provide for stick-force characteristics that will minimize the possibility
of pilots inadvertently overcontrolling the airplane.
22 The Zodiac designer also provided flight test data for the CH-600/601
(non-XL) airplanes. The data show that the stick forces are generally
somewhat lighter than those experienced on the CH-601XL but that the
gradients are constant until the airplane reaches at least 4 Gs.
Message 9
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| Subject: | Re: Sparky and other assorted experts. |
I agree. We should ignore your posts.
--------
Doug Sire 601XL
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246447#246447
Message 10
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| Subject: | Re: Putting Flutter Issue to Bed |
Hello Paul,
-
Good explanation...
If I will ask my wife if I should be flying or not...- I for sure will al
so be-grounded.
-
Saludos
Gary Gower
Flying from Chapala, Mexico.
701 912S- 240 hrs
building 601 XL- Jab 3300
Macho Flyer,- Wife grounded :-)
Do not archive.
--- On Tue, 6/2/09, Paul Mulwitz <psm@att.net> wrote:
Hi Dave,
My own decision was made based on my own criteria and my own situation.-
I searched my soul and discussed the situation with my wife (who also flies
) and reached the conclusion I would ground my plane, as suggested by the N
TSB, until the two mentioned changes were implemented.- If I am demonstra
ting resolve, it is merely that there have been no changes in the situation
that would convince me I should change my own decision.
Best regards,
Paul
XL grounded
=0A=0A=0A
Message 11
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| Subject: | Fire Extinguisher Sale |
I think it is a good deal, I've bought one.
http://www.woot.com/
--------
Pavel
CA
Zodiac XL N581PL (Reserved)
Stratus Subaru EA-81
Tail, flaps, ailerons, wings done, fuselage is on the table ....
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246453#246453
Message 12
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| Subject: | Re: Fire Extinguisher Sale |
Pavel,
Those fire extinguishers look like a good deal.? However, I would not have them
in my airplane for use in the cockpit.? In an in-flight emergency they might
put out a small fire, but the ingredients are very corrosive and would ruin a
lot of stuff in the airplane.? I would stick with Halon.
Jay Bannister
-----Original Message-----
From: pavel569 <pm569@HOTMAIL.COM>
Sent: Tue, 2 Jun 2009 10:10 am
Subject: Zenith-List: Fire Extinguisher Sale
I think it is a good deal, I've bought one.
http://www.woot.com/
--------
Pavel
CA
Zodiac XL N581PL (Reserved)
Stratus Subaru EA-81
Tail, flaps, ailerons, wings done, fuselage is on the table ....
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246453#246453
________________________________________________________________________
Email message sent from CompuServe - visit us today at http://www.cs.com
Message 13
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| Subject: | Re: Fire Extinguisher Sale |
I intend to have it in my shop or by hand when on ground. Not for flying.
--------
Pavel
CA
Zodiac XL N581PL (Reserved)
Stratus Subaru EA-81
Tail, flaps, ailerons, wings done, fuselage is on the table ....
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246465#246465
Message 14
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| Subject: | Re: Putting Flutter Issue to Bed |
> Recommendations extracted from the NTSB Report
>
> Require a comprehensive evaluation of the wing and aileron system on the
> Zodiac CH-601XL, including ground vibration tests, to identify design and/or
> operational changes that will reduce the potential for flutter; the
> evaluation should give significant consideration to the benefits of
> installing mass-balanced ailerons and should also address the adequacy of
> cable tension values specified by Zenair.
>
>
Recommendation met by GVT report.
>
> Evaluate the stick-force gradient of the Zodiac CH-601XL at the maximum aft
> center of gravity and notify pilots of the stick-force gradient that occurs
> at the aft center of gravity, especially at the higher G forces.
>
>
Issue already addressed before it was recommended. We were advised to add an elevator
stop quite some time ago. I added mine the weekend after it was recommended.
Took about 20-30 minutes. Any additional issue can easily be handled with
training. I'd like to see Zenith along with the FAA come out with a requirement
much as was done with SFAR 74. This had a major impact with the insurance
companies that were insuring Robinson helicopters. In something like a 601 specialized
training would reduce accidents to as close to zero as could be hoped
and would have the long term effect of making up for, statistically, the accidents
we have already had. Not to mention it would be a plus for those CFI-LS
out there that choose to use 601XLs.
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246472#246472
Message 15
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| Subject: | Re: Fire Extinguisher Sale |
I'm with Jay. A cheap fire extinguisher may well be a false economy.
I did like their warranty though.
> Warranty: None, it's a fire extinguisher
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246473#246473
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| Subject: | 601 XL tail skin |
Folks,
I'm having some issues getting the top of the skin on for my horizontal stabilizer.
I've checked that my table is flat and level and the 2x4" supports under the nose
is also flat.
When I try to get the top of the skin pressed down I can get all the witness marks
to align on the front and rear spars, as well as the ribs. However, the distance
from the table top to the bottom of the front spar is off by 20mm. The
level on the skin also shows level. Something doesn't quite add up.
Any advice or sockpuppet motivation I could get would be most appreciated.
Thanks!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246483#246483
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| Subject: | Re: Putting Flutter Issue to Bed |
Paul,
you need to sell yuor plane, obviously you will not be happy until you are flying
a Cessna.
Juan
-----Original Message-----
>From: Thruster87 <alania@optusnet.com.au>
>Sent: Jun 2, 2009 6:37 AM
>To: zenith-list@matronics.com
>Subject: Zenith-List: Re: Putting Flutter Issue to Bed
>
>
>
>psm(at)att.net wrote:
>> Hi Dave,
>>
>> While you may be correct about the NTSB changing their position on
>> the design changes, I seriously doubt that will happen.
>>
>> I don't think they made the demand for aileron balance based on
>> research about the Zodiac design. I think it was made based on the
>> experience in the industry that aileron balance makes safer
>> airplanes. According to a number of people I have contacted in this
>> regard, i[b]ndustry standard handling of this question has shown aileron
>> mass balancing is beneficial (i.e. saves lives) on all airplane
>> designs except for those that have fabric covered ailerons.[/b] Please
>> keep in mind that there have been a relatively high number of
>> structural failures on Zodiac XLs. That is why the NTSB was looking
>> at this particular design in the first place.
>>
>> I don't know why you made the comment about the difference in forces
>> for aileron vs. elevator travel. That is not an issue for me or the
>> NTSB. The issue is the clear flaw that as you increase the G's being
>> pulled by the plane it becomes easier to add more G's. While
>> training about this flaw might prevent some deaths it seems more
>> appropriate to actually fix the design. I don't know exactly what
>> this will take, but my sense is that it is not difficult to fix. I
>> don't believe any pilot would apply too much force to the stick on
>> purpose. I think this is possible in a panic situation or possibly
>> as a weird mistake where the passenger accidently kicks the stick or
>> some such thing.
>>
>> If the NTSB issues another letter saying they have decided to
>> withdraw their statement that these changes are needed then I will
>> consider dropping the same needs from my decision to ground my
>> plane. As it now stands, I need approved engineering changes from
>> Zenith or a related source for these issues before my plane gets
>> un-grounded. The longer it takes for Zenith to decide to create
>> those engineering changes the longer my plane will be grounded.
>>
>> Paul
>> XL Grounded
>>
>> I just balanced the ailerons and the elevators for a DC4 which are fabric and
there are many other aircraft with mass balanced fabric covered ailerons. Cheers
>>
>>
>
>
>Read this topic online here:
>
>http://forums.matronics.com/viewtopic.php?p=246427#246427
>
>
Message 18
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| Subject: | Re: 601 XL tail skin |
Lee it has been so long and somebody that did it more recently (or has a better
memory could probably be of more help but I remember a problem somewhat like
yours and the problem ended up being that I was misreading something. Go back
and look at the plans and the build manual and make sure you are not doing what
I did.
Lee Steensland wrote:
> Folks,
>
> I'm having some issues getting the top of the skin on for my horizontal stabilizer.
>
> I've checked that my table is flat and level and the 2x4" supports under the
nose is also flat.
>
> When I try to get the top of the skin pressed down I can get all the witness
marks to align on the front and rear spars, as well as the ribs. However, the
distance from the table top to the bottom of the front spar is off by 20mm. The
level on the skin also shows level. Something doesn't quite add up.
>
> Any advice or sockpuppet motivation I could get would be most appreciated.
>
> Thanks!
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246497#246497
Message 19
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| Subject: | Re: Putting Flutter Issue to Bed |
On Tue, Jun 02, 2009 at 04:03:58PM -0400, Juan Vega wrote:
> you need to sell yuor plane, obviously you will not be happy until you are
> flying a Cessna.
Horse exhaust and hogwash. Just because a plane is an experimental (or SLSA)
does not mean that it cannot adhere to generally accepted standards of safe
aircraft design, or that it gets a free pass for failing to do so. Would you
argue that a pilot of an experimental aircraft need not be trained to the
same standards as a pilot of a 172? It's the identical case.
--
Jay Maynard, K5ZC, PP-ASEL, CFI-SP http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (KFRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml
Message 20
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| Subject: | Re: Putting Flutter Issue to Bed |
Gig,
Although I do not believe anyone would criticize specialized training in the
XL (or for that matter any airplane you have not flown before). I find that
the XL is pretty easy to fly and is forgiving. I had never really flown the
XL before I flew my XL's first flight.(had a short ride at the controls at
the Zenith factory, but was not permitted to stall or land it).
I do not believe that the XL has a reputation for stall/spin type accidents
common to many other airplanes; in fact, during my Phase I and sometimes
when I do "air-work", I have purposefully tried cross controlling in various
flight regimes ( SLOW descending turns etc) and never have had the airplane
roll off into a departure. I have had it in stall buffet conditions and have
tried to get it to depart left or right also without success. I believe I
could get the airplane to depart, but I would have to really be highly
uncoordinated, or really stomp the rudder full during the stall and hold it
until probable departure.(have not tried this and do not plan to - unless
someone other than me wants to do a complete spin evaluation : ).
I believe that what everyone should be aware of is that you can easily
induce large elevator deflections with out trying hard - not a problem,
except at high speeds.
I really like the stick forces in pitch and wish the aileron were was a
little more "sensitive", but the ailerons also require little stick movement
(with more force) to start rolling/turning. I have no problems trimming in
roll or pitch.
Tony Graziano
XL/Jab; N493TG; 496 hrs/1098 landings in my XL.
----- Original Message -----
From: "Gig Giacona" <wrgiacona@gmail.com>
Sent: Tuesday, June 02, 2009 11:32 AM
Subject: Zenith-List: Re: Putting Flutter Issue to Bed
>
>
>> Recommendations extracted from the NTSB Report
>>
>> Require a comprehensive evaluation of the wing and aileron system on the
>> Zodiac CH-601XL, including ground vibration tests, to identify design
>> and/or
>> operational changes that will reduce the potential for flutter; the
>> evaluation should give significant consideration to the benefits of
>> installing mass-balanced ailerons and should also address the adequacy of
>> cable tension values specified by Zenair.
>>
>>
>
>
> Recommendation met by GVT report.
>
>
>>
>> Evaluate the stick-force gradient of the Zodiac CH-601XL at the maximum
>> aft
>> center of gravity and notify pilots of the stick-force gradient that
>> occurs
>> at the aft center of gravity, especially at the higher G forces.
>>
>>
>
>
> Issue already addressed before it was recommended. We were advised to add
> an elevator stop quite some time ago. I added mine the weekend after it
> was recommended. Took about 20-30 minutes. Any additional issue can easily
> be handled with training. I'd like to see Zenith along with the FAA come
> out with a requirement much as was done with SFAR 74. This had a major
> impact with the insurance companies that were insuring Robinson
> helicopters. In something like a 601 specialized training would reduce
> accidents to as close to zero as could be hoped and would have the long
> term effect of making up for, statistically, the accidents we have already
> had. Not to mention it would be a plus for those CFI-LS out there that
> choose to use 601XLs.
>
> --------
> W.R. "Gig" Giacona
> 601XL Under Construction
> See my progress at www.peoamerica.net/N601WR
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=246472#246472
>
>
>
Message 21
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| Subject: | Re: Putting Flutter Issue to Bed |
jmaynard wrote:
> On Tue, Jun 02, 2009 at 04:03:58PM -0400, Juan Vega wrote:
>
> > you need to sell yuor plane, obviously you will not be happy until you are
> > flying a Cessna.
> >
> >
>
> Horse exhaust and hogwash. Just because a plane is an experimental (or SLSA)
> does not mean that it cannot adhere to generally accepted standards of safe
> aircraft design, or that it gets a free pass for failing to do so. Would you
> argue that a pilot of an experimental aircraft need not be trained to the
> same standards as a pilot of a 172? It's the identical case.
> --
>
Jay
I don't think that is point Juan was trying to make. I think the point is that
there is no reasonable act that Zenith could take that would make the person he
replied to happy with they aircraft. The problem being this particular poster
thinks that anything the NTSB says is golden and he is also under the misconception
that the NTSB has the power to demand anything.
And just for the record the pilot of a 601XL doesn't have to be trained to the
same level as the pilot of a 172.
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246500#246500
Message 22
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| Subject: | Re: Putting Flutter Issue to Bed |
On Tue, Jun 02, 2009 at 02:00:35PM -0700, Gig Giacona wrote:
> I don't think that is point Juan was trying to make. I think the point is
> that there is no reasonable act that Zenith could take that would make the
> person he replied to happy with they aircraft. The problem being this
> particular poster thinks that anything the NTSB says is golden and he is
> also under the misconception that the NTSB has the power to demand
> anything.
I disagree. Zenith could come up with a balance weight kit for hte US, or
just make the one they developed for the UK avalable here, and find a fix
for the G force gradient issue, and I think Paul would be happy,
> And just for the record the pilot of a 601XL doesn't have to be trained to
> the same level as the pilot of a 172.
The differences have to do with the limited privileges of a sport pilot; the
standards for those elements that are in common are identical.
Perhaps I should have said "Skycatcher" rather than 172. After all, that's a
Cessna. In any event, the idea that sport pilots are less well trained than
private pilots needs to be shot down in flames whenever it comes up. There's
no reason in the word a sport pilot should be any less well trained than a
private pilot. (This was a hot button issue for my CFI-SP examiner, as it is
for me.)
The sport pilot rule is still controversial in some quarters. Accepting
anything less than the same level of safety in aircraft that is given by
part 23, and anything less than the same standard of training as a private
pilot, can only harm the cause - because it gives the naysayers ammunition.
--
Jay Maynard, K5ZC, PP-ASEL, CFI-SP http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (KFRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml
Message 23
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| Subject: | Re: Putting Flutter Issue to Bed |
The issue I was trying to address with added training is the one that the NTSB
calls out regarding decreased elevator pressure in the higher G edges of the flight
envelope. I have no personal evidence that these exist but I'll take the
NTSBs word for it until my plane is flying. I intend to address this during phase
1 testing. I have it scheduled in for hour 28.
tonyplane(at)bellsouth.ne wrote:
> Gig,
>
> Although I do not believe anyone would criticize specialized training in the
> XL (or for that matter any airplane you have not flown before). I find that
> the XL is pretty easy to fly and is forgiving. I had never really flown the
> XL before I flew my XL's first flight.(had a short ride at the controls at
> the Zenith factory, but was not permitted to stall or land it).
>
> I do not believe that the XL has a reputation for stall/spin type accidents
> common to many other airplanes; in fact, during my Phase I and sometimes
> when I do "air-work", I have purposefully tried cross controlling in various
> flight regimes ( SLOW descending turns etc) and never have had the airplane
> roll off into a departure. I have had it in stall buffet conditions and have
> tried to get it to depart left or right also without success. I believe I
> could get the airplane to depart, but I would have to really be highly
> uncoordinated, or really stomp the rudder full during the stall and hold it
> until probable departure.(have not tried this and do not plan to - unless
> someone other than me wants to do a complete spin evaluation : ).
>
> I believe that what everyone should be aware of is that you can easily
> induce large elevator deflections with out trying hard - not a problem,
> except at high speeds.
>
> I really like the stick forces in pitch and wish the aileron were was a
> little more "sensitive", but the ailerons also require little stick movement
> (with more force) to start rolling/turning. I have no problems trimming in
> roll or pitch.
>
> Tony Graziano
> XL/Jab; N493TG; 496 hrs/1098 landings in my XL.
>
>
>
> ---
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246509#246509
Message 24
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| Subject: | Re: 601 XL tail skin |
Take a look at my kitlog site and maybe it might trigger an idea. I scratch built
but the assembly process is the same.
--------
Ron Lendon, Clinton Township, MI
WW Corvair with Roy's Garage 5th bearing
Zodiac XL, ScrapBuilder ;-)
http://www.mykitlog.com/rlendon
Corvair Engine Prints:
http://home.comcast.net/~rlendon/site/
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246511#246511
Message 25
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| Subject: | Re: Putting Flutter Issue to Bed |
jmaynard wrote:
>
> I disagree. Zenith could come up with a balance weight kit for hte US, or
> just make the one they developed for the UK avalable here, and find a fix
> for the G force gradient issue, and I think Paul would be happy,
>
>
Why should there be a weight added? The GVT shows that the system, as designed,
works. Putting extra weight out in the wing can only add additional stress on
the design and God only knows what that will do.
The G force gradient can be dealt with with training if it exists. You have a flying
example can you tell me if the G force gradient does in fact exist? And
if so are you capable of flying the plane with that gradient now that you know
about it? If the answer to that last one is yes then you have just proved my
point about training if you can't you need to ground yourself.
> And just for the record the pilot of a 601XL doesn't have to be trained to
> the same level as the pilot of a 172.
>
>
The differences have to do with the limited privileges of a sport pilot; the
standards for those elements that are in common are identical.
Perhaps I should have said "Skycatcher" rather than 172. After all, that's a
Cessna. In any event, the idea that sport pilots are less well trained than
private pilots needs to be shot down in flames whenever it comes up. There's
no reason in the word a sport pilot should be any less well trained than a
private pilot. (This was a hot button issue for my CFI-SP examiner, as it is
for me.)
The sport pilot rule is still controversial in some quarters. Accepting
anything less than the same level of safety in aircraft that is given by
part 23, and anything less than the same standard of training as a private
pilot, can only harm the cause - because it gives the naysayers ammunition.
--
[/quote]
I doubt anyone thought you'd have the same level of safety in S-LSA as you would
with part 23 aircraft. Why do you think the the FAA limited the weight to 1320
lbs and only allowed it to be a pilot plus one aircraft. The answer is to keep
down the damage on the ground and the body count down in an accident. Otherwise
they would let LSA pilots fly 172s with 4 people on board in VFR/Day only.
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246515#246515
Message 26
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| Subject: | Re: Putting Flutter Issue to Bed |
Paul--- Has anybody played with the idea of installing two equal
strength coil or flat springs somewhere at the bottom of the control
stick, to add resistance as the stick increases deflection? They might
have to be fairly stiff, but they might deter the heavy-handed or unwary
from bankin' and yankin'. Just a thought.
Paul R.
----- Original Message -----
From: Paul Mulwitz<mailto:psm@att.net>
To: zenith-list@matronics.com<mailto:zenith-list@matronics.com>
Sent: Monday, June 01, 2009 9:31 PM
Subject: Re: Zenith-List: Putting Flutter Issue to Bed
<psm@att.net<mailto:psm@att.net>>
Indeed, the NTSB identified another problem - one which I think might
explain all the accidents. It is the stick gradient problem that
makes it easier to pull additional G's as you pull additional G's.
The NTSB demanded both this be fixed and aileron mass balancing be
added. I hope the Zenair folks are going to release design changes
to resolve those issues. It really doesn't matter whether the
changes are justified by German engineers or not. The changes are
still needed to satisfy the NTSB demands.
Paul
XL grounded
do not archive
At 07:21 PM 6/1/2009, you wrote:
>Just because flutter isn't the issue (I agree with that) doesn't mean
that
>there's not some other problem with the aircraft itself. We just
don't know.
http://www.matronics.com/Navigator?Zenith-List<http://www.matronics.com/N
avigator?Zenith-List>
http://www.matronics.com/contribution<http://www.matronics.com/contributi
on>
Message 27
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| Subject: | Re: Putting Flutter Issue to Bed |
Hi Paul,
I am an experienced engineer, but my field is electronics rather than
mechanical or aeronautical design. I don't know the best way to deal
with the stick design problem. I really hope the experts at
Zenair/Zenith will design and issue an appropriate change.
That said, I will make a comment or two based on things I have heard
- mostly on this list.
I think adding springs or bungie cords to the stick would make the
forces heavier, but might not have any impact on the real
problem. The real problem seems to be that it gets progressively
easier to pull G's as you pull more G's. So, if you are already
pulling 3 G's a little more pull on the stick might get you to 6 G's
rather than 3.2.
The change that seems to be a more appropriate fix is to add a dense
weight to the bottom of the stick. This would be impacted by pulling
G's so that the more force on the weight the harder it gets to
increase the load on the wings. This would still present the nice
light stick forces when the plane is lightly loaded with G's but make
it progressively more difficult to add more load.
Paul
XL Grounded
do not archive
At 03:22 PM 6/2/2009, you wrote:
>Paul--- Has anybody played with the idea of installing two equal
>strength coil or flat springs somewhere at the bottom of the control
>stick, to add resistance as the stick increases deflection? They
>might have to be fairly stiff, but they might deter the heavy-handed
>or unwary from bankin' and yankin'. Just a thought.
>
>Paul R.
Message 28
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| Subject: | Re: Putting Flutter Issue to Bed |
As far as taking everything the NTSB says as golden one must also realize
that several members of the board are political appointments .
Wade Jones South East Texas
----- Original Message -----
From: "Gig Giacona" <wrgiacona@gmail.com>
Sent: Tuesday, June 02, 2009 4:00 PM
Subject: Zenith-List: Re: Putting Flutter Issue to Bed
>
>
> jmaynard wrote:
>> On Tue, Jun 02, 2009 at 04:03:58PM -0400, Juan Vega wrote:
>>
>> > you need to sell yuor plane, obviously you will not be happy until you
>> > are
>> > flying a Cessna.
>> >
>> >
>>
>> Horse exhaust and hogwash. Just because a plane is an experimental (or
>> SLSA)
>> does not mean that it cannot adhere to generally accepted standards of
>> safe
>> aircraft design, or that it gets a free pass for failing to do so. Would
>> you
>> argue that a pilot of an experimental aircraft need not be trained to the
>> same standards as a pilot of a 172? It's the identical case.
>> --
>>
>
>
> Jay
>
> I don't think that is point Juan was trying to make. I think the point is
> that there is no reasonable act that Zenith could take that would make the
> person he replied to happy with they aircraft. The problem being this
> particular poster thinks that anything the NTSB says is golden and he is
> also under the misconception that the NTSB has the power to demand
> anything.
>
> And just for the record the pilot of a 601XL doesn't have to be trained to
> the same level as the pilot of a 172.
>
> --------
> W.R. "Gig" Giacona
> 601XL Under Construction
> See my progress at www.peoamerica.net/N601WR
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=246500#246500
>
>
>
Message 29
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| Subject: | Re: Putting Flutter Issue to Bed |
Hi, Gig.
I just can't stand it any longer. As much as I try not to get down in the mud here,
there comes a point when I just can't let this stuff go by without comment.
Several posters here have decided that, despite the positive results of the GVT
and the lack of any single causal factor in the six 601 series crashes worldwide,
that there still remains a "problem" with the design. Even though these guys
fully admit they don't have any personal expertise in aircraft design, they
still insist on offering "solutions" such as aileron mass balancing and changing
the dynamics of the control system! What chutzpah.
Their continued insistance of an inherent design flaw in the 601 does very real
damage, to which these guys seem oblivious. All of us who have invested our hard
earned money and time in Chris Heintz's design now are faced with significant
loss in the values of our aircraft, are now questioned about our sanity in
flying the airplanes by those who simply don't know any better, and an undeserved
shadow has been placed on all Zenith Aircraft designs as well.
Here's what I now know:
Flutter is NOT an issue IF aileron cable tensions are maintained to spec. They
even showed no negative traits down to 10 pounds (less than HALF of what's specifiedby
the factory).
The 601XL has stiff ailerons but a very sensitive elevator. You need an effective
elevator at the 601's low rotation and landing speeds, but it could rip the
wings off if suddenly deflected downward to it's original limit at high cruise
airspeeds. So the factory recommended that it be limited to 15 degrees of down
deflection.
So the bottom line is that maintaining aileron cable tension, installing the down
stop, and flying with a light touch on the elevator should allow us all to
enjoy this design without irrational fear. Is this so much to ask? I don't make
a habit of riding my motorcycle into solid walls either, even though I'm given
every opportunity to do so. Does this mean there's an inherent flaw with my
bike?
The 601 is MOST DEFINITELY NOT a Cessna 172! Any ham fisted pilot can fly a 172,
and will usually get to their destination without harm no matter how rough they
are with the yoke. (I used to own a Skyhawk, and I was bored to tears after
the novelty of being airborne wore off.) The 601 handles much better, and is
very responsive to the pilot's control inputs. It teaches you to fly with a light,
firm touch, and rewards you by becoming an extension of yourself. But it
is NOT way, way overbuilt like a Cessna or Piper or Beech or Mooney or Grumman!
It is, by design, much lighter and needs to be flown with respect for what
the designer intended. To do otherwise is just asking for it. And to insist that
these flying characteristics are indicative of some kind of "problem" or "flaw"
is tantamount to admitting that, instead of being pilots, we're really only
glorified passengers incapable of anything beyond a minimal level of flying
skill.
I've never seen such chest-thumping mule-headedness, in spite of growing evidence
to the contrary. I can only conclude that, in spite of its low cost, simple
construction, precise and easy handling, that the 601 really isn't for everybody.
Some really would be much better served by a Skyhawk or Cherokee.
Rick Lindstrom
Zenvair N42KP
-----Original Message-----
>From: Gig Giacona <wrgiacona@gmail.com>
>Sent: Jun 2, 2009 5:52 PM
>To: zenith-list@matronics.com
>Subject: Zenith-List: Re: Putting Flutter Issue to Bed
>
>
>jmaynard wrote:
>>
>> I disagree. Zenith could come up with a balance weight kit for hte US, or
>> just make the one they developed for the UK avalable here, and find a fix
>> for the G force gradient issue, and I think Paul would be happy,
>>
>>
>Why should there be a weight added? The GVT shows that the system, as designed,
works. Putting extra weight out in the wing can only add additional stress on
the design and God only knows what that will do.
Message 30
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| Subject: | Re: Putting Flutter Issue to Bed |
Jay
i guess my point is, we are all pilots. Not car driverss or sled drivers, or surfers,
but pilots, who choose to fly a vehicle that goes 150-160 mph. there
are 2000 of these zodiacs flying. the plane is well designed, but the pilots
are the last ones blamed not for just pilot skills but for pilot "in command",
meaning, that we as the ones at the control are the owners of our fate.
we built the plane, we test flew it. we chose to be in that little bubble canopy
buzzing around. We are accountable for our own actions. You cannot engineer
every single variable of risk out of the whole event. impossible. the experts
came back and stated clearly not a design issue. Grounding the plane is to
ground oneself, and your discomfort in assuming responsibilty for yourself and
that as a pilot "in command" it is completly up to us. You will pull the card
that an AMD plane crashed. So what! SO did an Airbus yesterday due to electrical
issues or Godforbid! It crashed for a reason we will never know!. Regardless
of the design or the experts building it, there is still risk. the odds
on a larger aircraft ae more in the favor of more odds of human design flaw
or build error, 1000s of people and 50,000 plus hours of build time in one
plane. Pull my head out of the sand? That happened the day I built it and
signed the papers saying " you built it, you, are Pilot in Command, Zenith Desinged
it, But I built it! Whose head is in the sand?
Politically there will be some BS design adjustment recommendation.
Then probably in time, there may be God forbid, another crash. What then? keep
blaming the design?, how about starting to look at the builder or the flyer
for once!
Does that sound like head in the sand?
Juan
-----Original Message-----
>From: Jay Maynard <jmaynard@conmicro.com>
>Sent: Jun 1, 2009 10:21 PM
>To: zenith-list@matronics.com
>Subject: Re: Zenith-List: Putting Flutter Issue to Bed
>
>
>On Mon, Jun 01, 2009 at 09:40:39PM -0400, Juan Vega wrote:
>> See Below. Lets Quit the BS, as the test result show the Flutter is the
>> wrong tree to bark up. Lets look a the quality of the builds, even the AMD
>> one or the lack Pilot control.
>
>Just because flutter isn't the issue (I agree with that) doesn't mean that
>there's not some other problem with the aircraft itself. We just don't know.
>
>Of course, you're invulnerable, so you'll never have a problem.
>
>Come on, Juan, pull your head out of the sand.
>--
>Jay Maynard, K5ZC, PP-ASEL, CFI-SP http://www.conmicro.com
>http://jmaynard.livejournal.com http://www.tronguy.net
>Fairmont, MN (KFRM) (Yes, that's me!)
>AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml
>
>
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| Subject: | Re: Putting Flutter Issue to Bed |
Juan, interesting that you mentioned the Air France crash. I was just watching
the Weatherer Channel before heading off to bed and they had an airline pilot
saying, "If you exceed the design of any plane you will rip the wings off of it."
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=246555#246555
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| Subject: | Re: Fire Extinguisher Sale |
They also make visibility out of the cockpit near zero due to a
combination of the powder adhering to the inside surface of the canopy
and the irritation to the eyes. Halon is definitely the way to go in
the cockpit until somebody develops a suitable replacement.
On Jun 2, 2009, at 11:35 AM, jaybannist@cs.com wrote:
> Pavel,
>
> Those fire extinguishers look like a good deal. However, I would
> not have them in my airplane for use in the cockpit. In an in-
> flight emergency they might put out a small fire, but the
> ingredients are very corrosive and would ruin a lot of stuff in the
> airplane. I would stick with Halon.
>
> Jay Bannister
>
>
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
do not archive.
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