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Terry Phillips

Joined: 11 Jan 2006
Posts: 346
Location: Corvallis, MT

Posted: Tue Jun 16, 2009 5:18 pm Post subject: ZBAG, a respectful question: a modest answer

Interesting question,  Kevin



Since we have ample evidence that flutter does occur in real CH601XL's in 

flight, I guess that your question translates to,



"What evidence would it take to prove to me that the pilots who have 

experienced flutter in the 601XL were lying or mistaken?"



Gosh, I don't know. All of the pilots who reported flutter were more 

experienced than I am. One had thousands of hours. I find their reports 

convincing. I have no reason to believe that they were lying. One person 

who reported flutter in the 601XL tests was Mathieu Heintz (look up his Sun 

n Fun AvWeb podcast). I guess that I would have to conclude that Mathieu is 

either incompetent or dishonest. I am not ready to make that conclusion. We 

have at least two second hand reports of flutter in 601XL from Chris Heintz 

(look through Chris's letters to owners). I would have to conclude that 

Chris was wrong in his letter.



Here's what I think I know. If the balance on an aileron satisfies the 

criteria in A&E Report 45, then my understanding is that the FAA is willing 

to forego flutter testing for certificated airplanes. That's simple enough 

for me. Add about 5 lbs or so to each wing in a well designed 

counterbalance, and according to established criteria, aileron flutter will 

not happen. If you look at Fig.  24 of Prof. Weltin's GVT report, you'll 

see a pretty reasonable design for a 601XL aileron counterbalance. I 

suspect that Zenair has a better drawing of that somewhere. It looks good 

to me.



Hey, E-AB aircraft builders can do whatever they want to their airplanes. 

If you do not believe that flutter is a problem, Kevin, then don't add 

counterbalances.  It would be most revealing if half the fleet added the 

counterbalances, plus the LAA mods, whatever they work out to be, and half 

the fleet flew 601XL's made exactly to the prints. Then in a couple of 

years we would find out whether the counterbalances, et al, made a 

difference--or not. So those of you who have absolute faith in the design, 

you can be the control group. Others, whose faith is not so solid can make 

the mods they find appropriate. A couple of years of flying should tell the 

tale. I cannot understand why anyone with absolute faith in the design 

would feel threatened by the mods that others make to their planes. If you 

are right, you can have the last laugh at those of us who lack your 

absolute faith. For sure, the last thing I would want to do is to impose my 

own personal  concerns on you.



So, I suggest that everyone tone down their rhetoric. Then make the mods to 

your airplane that makes sense to you, or not, and in a couple of years we 

should have the answer. I've got a pretty good idea what I will do. How 

about you, Kevin?



Terry

At 06:03 AM 6/16/2009 -0700, you wrote:

 	  Quote: 	
		  My question is directed to anyone who has design questions regarding the 

601XL.



What evidence would it take to prove to you the 601XL is free of flutter?



Regards,

Kevin Kinney


	




Terry Phillips  ZBAGer

ttp44~at~rkymtn.net

Corvallis MT

601XL/Jab 3300 s .. l .. o .. o .. w build kit - Tail, flaps, & ailerons 

are done; waiting on the wings

http://www.mykitlog.com/N47TP/

_________________
Terry Phillips
Corvallis, MT
ttp44<at>rkymtn.net
Zenith 601XL/Jab 3300 slow build kit - Tail feathers done; working on the wings.

rtdin

Joined: 16 Mar 2008
Posts: 46
Location: Florida panhandle

Posted: Tue Jun 16, 2009 9:17 pm Post subject: ZBAG, a respectful question: a modest answer

I so wanted to stay out of this, however I cannot stand by and allow a few who don't know me to imply that because I am a member of ZBAG, I would like to kill off the 601XL. Doesn't pass the sniff test. I have a big investment in time and money in my project. It's on hold for the present. My grand kids will not be allowed in it until a few things get ironed out.

 

 As Rick says, "Pilots that only fly FAR 23 A/C have trouble with LSAs." I guess I may have some trouble despite owning a Champ and Luscombe. Despite having many hours in FAR 23, 27, 29, CAR 3 and a couple of E-AB A/C, including a 601XL, I guess I don't have a chance. My first thought is if this is the horse that can't be rode and it has known bad traits, Why put low timers in it? Can't these quirks be fixed? I used to instruct in helos and sailplanes and I cannot trust an aircraft that will scare a low time pilot. I have faith that the LAA will civilize the 601XL.

 

 I bet that most of the ZBAG haters have only gone on the site to use their flame throwers. Its a shame that they don't take some time to go through the stuff in the "Files" section. That stuff is available to everybody and may even be educational.

 

 Terry has some good points about control balancing. Its hard to find anything flying that doesn't use mass balance. It is that accepted world wide. See Zenair Newsletters 40 and 41 for a Zenith design. Most small planes use 1.5 to 2 LB per wing. The Sonex uses 5LB and is trouble free. 

 

 If there were no accidents with the 601XL, we would not be having this conversation and I would have my project finished. 

 

 Bob Dingley

 601XL (holding at the wings)

 

 

 

 

**************

Download the AOL Classifieds Toolbar for local deals at your fingertips. (http://toolbar.aol.com/aolclassifieds/download.html?ncid=emlcntusdown00000004)  [quote][b]

kkinney

Joined: 11 Jan 2006
Posts: 42

Posted: Wed Jun 17, 2009 4:36 am Post subject: Re: ZBAG, a respectful question: a modest answer

> How about you, Kevin?



I freely admit I know far less that everyone else seems to and I apologize for answering a question with a question.  But what I do depends on the answer to that question.



Have there been any suspect accidents on aircraft with flex hinges?



Regards,

kk

tonyplane(at)bellsouth.ne
Guest

Posted: Wed Jun 17, 2009 5:11 am Post subject: ZBAG, a respectful question: a modest answer

The only actual aileron flutter that I have read about with the XL is those 

who reported it, slowed down to stop it, and post flight found that their 

cables were slack.  The also reported that after tightening the cables, the 

flutter went away.



In the one report of  "wing flutter", over the turbulent rising air mass of 

a powerplant, the pilot stated he DOVE down any away to stop the 

"flutter"!!!!!!!!!!!!!!!??????--try increasing airspeed with real flutter 

and see what happens.



Also, what some overlook is:

See Page 6 of the NTSB Report where they report as part of Zenith's 

Certification, Zenith did IN FLIGHT FLUTTER TESTING of the XL.



Tony Graziano

XL/Jab; N493TG,  502 hrs.



---

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Wed Jun 17, 2009 5:49 am Post subject: Re: ZBAG, a respectful question: a modest answer

 	  rtdin wrote: 	
		   I used to instruct in helos and sailplanes and I cannot trust an aircraft that will scare a low time pilot. 	




If you instructed in helicopters then I'm sure you are familiar with SFAR74 and the issues with the Robinson R22& R44 that caused it. We may well have a similar though much less pervasive with the 601XL where additional training is needed.



The issues that Rick raised were not 601XL specific but were about the new LSAs in general and were put forth by the insurance companies when they saw a correlation between high time pilots having trouble with the light and responsive LSA aircraft that they started flying with little or no transition training.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

jmaynard

Joined: 27 Feb 2008
Posts: 394
Location: Fairmont, MN (FRM)

Posted: Wed Jun 17, 2009 6:10 am Post subject: ZBAG, a respectful question: a modest answer

On Wed, Jun 17, 2009 at 06:49:16AM -0700, Gig Giacona wrote:

 	  Quote: 	
		   The issues that Rick raised were not 601XL specific but were about the new

 LSAs in general and were put forth by the insurance companies when they

 saw a correlation between high time pilots having trouble with the light

 and responsive LSA aircraft that they started flying with little or no

 transition training.


	


I haven't actually done any instruction for real (seems there's a lack of

demand), but I have had a few other pilots fly my airplane with me aboard

now. I know that it took me a while to get used to the sensitive elevator. I

make a point of telling other pilots who fly with me that the elevator is

sensitive (and the pitch trim even more so), and give them a chance to try

it up in the air while I'm ready to intervene if things get too crazy.



I had one guy just about to take his private check ride aboard one time. I

let him do the takeoff; I told him to lift off at 60 KIAS, then lower the

nose and fly away at 70, accelerating to 80 once at 500 AGL. (I've found

this to work well in getting the best climb performance. Vx at 57 KIAS?

Yeah, right.) He was a bit too aggressive in lowering the nose, and I

quickly grabbed the stick before we found ourselves hitting nose first. He

was quite surprised by the pitch sensitivity; in retrospect, I should have

explained what was going to happen before then (and have done so with other

pilots since).



This only applies to the elevator, BTW; other pilots have said that the

ailerons and rudder are much heavier in feel, and took no real adjustment.



Yes, transitioning into the Zodiac takes some dual. I'm not sure 5 hours is

warranted for every pilot, but that seems to be the industry standard. Is

this an explanation for problems we've seen? Possibly. Is it *the*

explanation? That very much remains to be proven.

-- 

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

_________________
Jay Maynard, K5ZC
AMD Zodiac XLi N55ZC

tigerrick(at)mindspring.c
Guest

Posted: Wed Jun 17, 2009 6:11 am Post subject: ZBAG, a respectful question: a modest answer

Hi, Bob. Rick here.



 	  Quote: 	
		  As Rick says, "Pilots that only fly FAR 23 A/C have trouble with LSAs." I 

guess I may have some trouble despite owning a Champ and Luscombe. Despite 

having many hours in FAR 23, 27, 29, CAR 3 and a couple of E-AB A/C, including 

a 601XL, I guess I don't have a chance. My first thought is if this is the 

horse that can't be rode and it has known bad traits, Why put low timers in 

it? Can't these quirks be fixed? I used to instruct in helos and sailplanes 

and I cannot trust an aircraft that will scare a low time pilot. I have 

faith that the LAA will civilize the 601XL.


	


Please don't misquote me, or attribute meanings to my posts that were never intended.



What I said was there is a disturbing uptick of accidents in LSAs with experienced pilots who fly them like the Part 23 aircraft they are used to. I DID NOT say "Pilots that only fly FAR 23 A/C have trouble with LSAs" as you posted. What I said, in a nutshell, was that pilots who expect the same weather capability from an LSA compliant design frequently have unpleasant surprises, and this is NOT specific to the 601 airframe. I've found the 601XL very easy to fly, takes off slow, lands slow, and is very docile in the air. The closest I could get to a stall was a mush. But with an empty weight of only 800 pounds or so and light wing loading, it's going to respond to every bump or patch of rough air, and tell you about it.



With your myriad flying experience, I would be very surprised if you had any problems at all with the 601. And it's interesting that low time pilots don't seem to have a problem with the 601 at all.



I choose my words carefully, and I resent others twisting them to derive meanings never intended.



Rick Lindstrom

N42KKP

d.goddard(at)ns.sympatico
Guest

Posted: Wed Jun 17, 2009 6:49 am Post subject: ZBAG, a respectful question: a modest answer

Quite possible, although at present it's just another idea. Do have any 

ideas on what might be done or has Zenith identified it as an issue? Can you 

think of any small change to the existing design that would mitigate the 

problem if it exists?



These are the types of discussions we SHOULD be having.



---

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Wed Jun 17, 2009 7:07 am Post subject: Re: ZBAG, a respectful question: a modest answer

 	  d.goddard(at)ns.sympatico wrote: 	
		  Quite possible, although at present it's just another idea. Do have any 

ideas on what might be done or has Zenith identified it as an issue? Can you 

think of any small change to the existing design that would mitigate the 

problem if it exists?



These are the types of discussions we SHOULD be having.



--- 	




Agreed it is exactly the type of discussion. But the fix for this issue isn't a design change it is a training issue.



To support this I put forth the theory that the reason that none of the accident aircraft that have suffered airframe failure were flown by pilots that flew the airplane during its' 25-40 phase 1 period. The first part of which a pilot would presumably be taking extra care in maneuvering the aircraft and learning its characteristics.



Let's assume for a second that the minimum a design change to mitigate a light elevator is going to cost is $1000/plane. (Nothing in a plane costs less than that.) That will buy you a minimum of 20 hours of CFI time. And that 20 hours will do more to assure your future safety than any design change ever would. That is not to say I think it takes 20 hours. 5 should do it and will make insurance companies happy.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

d.goddard(at)ns.sympatico
Guest

Posted: Wed Jun 17, 2009 8:25 am Post subject: ZBAG, a respectful question: a modest answer

If Zenith feels that extra training to overcome the issue is appropriate and 

issues an advisory to the effect then maybe that is enough. I expect it 

would only make things worse as it would create the illusion of an aircraft 

that is difficult to fly and I don't think that's true. So far Zenith has 

chosen to address it with a required design modification in the form of 

elevator stops if I understand things correctly.



A design change to actually alter the stick forces is only an idea, as yet 

unproved, unapproved and not required. In fact I would not like to see one 

required, but if there is an issue that a change could address in a similar 

fashion to the not required balanced ailerons I think it would be worthwhile 

to explore it as an option. It's always nice to have options.



Zenith will not require changes from their builders without substantial 

proof that there actually IS an issue and a need.  So far they have 

addressed the issue with elevator stops, REQUIRED I think. I don't think 

ZBAG had anything to do with that requirement it was due to the sensitive 

pitch aspect of the design and the accidents.



So which approach do you think is better in the long run, training to 

address a particular and possibly unusual aspect of the airframe or an 

option to bring the aircraft more in line with normal practice. I'd be happy 

with both.



 	  Quote: 	
		   



 Agreed it is exactly the type of discussion. But the fix for this issue 

 isn't a design change it is a training issue.



 To support this I put forth the theory that the reason that none of the 

 accident aircraft that have suffered airframe failure were flown by pilots 

 that flew the airplane during its' 25-40 phase 1 period. The first part of 

 which a pilot would presumably be taking extra care in maneuvering the 

 aircraft and learning its characteristics.

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Wed Jun 17, 2009 8:58 am Post subject: Re: ZBAG, a respectful question: a modest answer

The elevator stops don't effect the issue brought up by the NTSB where the elevator has less resistance as Gs increase. They just reduce the amount of down elevator you have available. A design change to change that would probably be complex and expensive. (Especially for the S-LSA planes.) Though I have yet to see anyone who flies a 601XL confirm this condition actually exists to a point where they don't feel they can control the aircraft.  



I'd be willing to bet that somewhere on the Zenith site it already suggests that a pilot get transition training before flying any of their planes. That is the sort of CYA stuff companies love.



Training is never a bad thing. Pilot certificates all the way up through ATP are a license to learn. The FAA knows this and is why they have developed the Wings Program and have set up the Flight Review requirements the way they have.The insurance companies know it and are starting to require transition training.



SFAR 74 that was developed for the Robinson R22 & R44 and took a couple of years to develop. That SFAR requires specific training and log book entries for every pilot that flies those helicopters no matter if it is zero hour student or an pilot that is transitioning from 3000 hours in an Apache.

 	  d.goddard(at)ns.sympatico wrote: 	
		  If Zenith feels that extra training to overcome the issue is appropriate and 

issues an advisory to the effect then maybe that is enough. I expect it 

would only make things worse as it would create the illusion of an aircraft 

that is difficult to fly and I don't think that's true. So far Zenith has 

chosen to address it with a required design modification in the form of 

elevator stops if I understand things correctly.



A design change to actually alter the stick forces is only an idea, as yet 

unproved, unapproved and not required. In fact I would not like to see one 

required, but if there is an issue that a change could address in a similar 

fashion to the not required balanced ailerons I think it would be worthwhile 

to explore it as an option. It's always nice to have options.



Zenith will not require changes from their builders without substantial 

proof that there actually IS an issue and a need.  So far they have 

addressed the issue with elevator stops, REQUIRED I think. I don't think 

ZBAG had anything to do with that requirement it was due to the sensitive 

pitch aspect of the design and the accidents.



So which approach do you think is better in the long run, training to 

address a particular and possibly unusual aspect of the airframe or an 

option to bring the aircraft more in line with normal practice. I'd be happy 

with both.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

d.goddard(at)ns.sympatico
Guest

Posted: Wed Jun 17, 2009 9:29 am Post subject: ZBAG, a respectful question: a modest answer

No the stops do not affect the forces, they stop a pilot from inadvertantly 

applying too much elevator as a consequence of the decreasing force. That's 

certainly one way to go, and by far the easiest and least expensive. Do you 

have an objection to an optional change that addresses the issue in a 

different way? I have no idea what it would cost as the option doesn't 

exist, I'm not sure we could simply assume it would be expensive or 

complicated, we could likely assume it would not be required as a retrofit.



---

Scotsman

Joined: 27 Aug 2007
Posts: 89
Location: Johannesburg, South Africa

Posted: Wed Jun 17, 2009 10:19 am Post subject: Re: ZBAG, a respectful question: a modest answer

Just a quick question.....



Is there a simpler "fix" for the pitch sensitivity whereby lengthening the lower and upper elevator horn would reduce the degrees of deflection per cm that the stick is moved in pitch?  Is there sufficient space in the rear of the fuselage to accommodate this?



If possible this would be cheap alternative.  Any thoughts anyone?



James

_________________
Cell +27 83 675 0815

Terry Phillips

Joined: 11 Jan 2006
Posts: 346
Location: Corvallis, MT

Posted: Wed Jun 17, 2009 10:39 am Post subject: ZBAG, a respectful question: a modest answer

Yep, that's the way I see it also. Tight cables, no flutter. Loose cables, 

yes flutter.



Relying on tight cables to prevent flutter does not meet FAA standards for 

certificated airplanes. But we're mostly talking E-AB aircraft here, and 

E-AB aircraft do not have to meet FAA standards. So, if you are happy with 

relying on tight cables to prevent flutter in your E-AB 601XL, then that is 

the way you should go. Or, if you think that, just maybe, the FAA has good 

reasons for not relying on tight cables to prevent flutter, then you might 

want to take additional steps.



I've tried to transcribe part of Mathieu Heintz AvWeb Podcast. What I hear is:



 	  Quote: 	
		  "the latest thing they've just completed now is a series of flutter tests 

in a wind tunnel"



"What we see from there is very clearly that when we have tight control 

cables per design requirements, that we do not have a flutter problem with 

the airplane. When you loosen up the cables, sure enough we get some 

flutter. It's not flutter in the sense that it's going to rip a wing 

apart, but it's enough to scare a pilot. Then when we put a mass balance 

weight with the loose control cables, then sure enough that goes away."


	


So, it seems that the 601XL wing is prone to flutter with loose cables, and 

that aileron counterbalance will prevent 601XL aileron flutter, even with 

loose cables. The choice is yours.



Terry

At 08:10 AM 6/17/2009 -0500, you wrote:

[quote]



The only actual aileron flutter that I have read about with the XL is 

those who reported it, slowed down to stop it, and post flight found that 

their cables were slack.  The also reported that after tightening the 

cables, the flutter went away.



In the one report of  "wing flutter", over the turbulent rising air mass 

of a powerplant, the pilot stated he DOVE down any away to stop the 

"flutter"!!!!!!!!!!!!!!!??????--try increasing airspeed with real flutter 

and see what happens.



Also, what some overlook is:

See Page 6 of the NTSB Report where they report as part of Zenith's 

Certification, Zenith did IN FLIGHT FLUTTER TESTING of the XL.



Tony Graziano

XL/Jab; N493TG,  502 hrs.



---

_________________
Terry Phillips
Corvallis, MT
ttp44<at>rkymtn.net
Zenith 601XL/Jab 3300 slow build kit - Tail feathers done; working on the wings.

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Wed Jun 17, 2009 10:55 am Post subject: Re: ZBAG, a respectful question: a modest answer

I can't think of a simple or cost effective way to modify the design that would address this issue. I have no doubt that someone could design a complex system of weights and/or pulleys that would do it but complex isn't why I decided to build a 601XL and I'm not that hot for a complex change for a problem that shouldn't even show itself except at the edges of the flight envelope and can be trained around.



As far as changing the length of the upper and lower elevator horns you then get into the issue that there isn't enough room in the cockpit for the stick to move all the way.

 	  d.goddard(at)ns.sympatico wrote: 	
		  No the stops do not affect the forces, they stop a pilot from inadvertantly 

applying too much elevator as a consequence of the decreasing force. That's 

certainly one way to go, and by far the easiest and least expensive. Do you 

have an objection to an optional change that addresses the issue in a 

different way? I have no idea what it would cost as the option doesn't 

exist, I'm not sure we could simply assume it would be expensive or 

complicated, we could likely assume it would not be required as a retrofit.



---

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

tonyplane(at)bellsouth.ne
Guest

Posted: Wed Jun 17, 2009 11:19 am Post subject: ZBAG, a respectful question: a modest answer

It would appear from what I have read that cables have to be very loose 

(slack) such as the stick can be moved without initial movement of the 

ailerons.  A preflight check and a "check controls are free and proper" 

before flight check should, I believe, detect improper (slack) cable 

tension.



Tony Graziano

XL/Jab: N493TG; 502 hrs



---

kkinney

Joined: 11 Jan 2006
Posts: 42

Posted: Wed Jun 17, 2009 11:21 am Post subject: Re: ZBAG, a respectful question: a modest answer

 	  Scotsman wrote: 	
		  

Is there a simpler "fix" for the pitch sensitivity whereby lengthening the lower and upper elevator horn would reduce the degrees of deflection per cm that the stick is moved in pitch? 	




Of the top of my head, I'd say there isn't much room to spare.  It would seem to alter more flight characteristics than just pitch sensitivity, such as reducing max elevator deflection.



Assuming you have the original single stick, reducing sensitivity could be accomplished by adding a friction plate where the stick attaches at the torque tube.  That would accomplish the single goal of reducing pitch sensitivity.  I'm not an aero-engineer, so I can not say what else may be affected.



This could be something to ask the factory.



Regards,

Kevin Kinney

d.goddard(at)ns.sympatico
Guest

Posted: Wed Jun 17, 2009 12:10 pm Post subject: ZBAG, a respectful question: a modest answer

I can't think of one either, but I could not have conceived a way to do away 

with aileron cables and install push/pull tubes and that's been done. It 

also looked fairly straightforward and easy to do while building.  It's a 

good reason to try to run these questions past a group of peers and see who 

might have an idea. There's no reason to simply dismiss the notion as 

complex or expensive when it doesn't exist. If a system is devised, I have 

extreme doubts that anyone would be required to install it. It would simply 

be an option for those who want it, do you object?

---

n801bh(at)netzero.com
Guest

Posted: Wed Jun 17, 2009 12:39 pm Post subject: ZBAG, a respectful question: a modest answer

Ok. I am getting confused again <GG>   Mathieu said  >"the latest thing they've just completed now is a series of flutter tests 

 	  Quote: 	
		  in a wind tunnel. 

Is the GVT considered a wind tunnel test or was there two  seperate tests performed ?? 
	


do not archive

Ben Haas

N801BH

www.haaspowerair.com



--------

Terry Phillips

Joined: 11 Jan 2006
Posts: 346
Location: Corvallis, MT

Posted: Wed Jun 17, 2009 8:49 pm Post subject: ZBAG, a respectful question: a modest answer

Apparently, the tests for the DAeC included several components  ground vibration tests (GVT)  
Load tests, probably to German microlight MTOW of 472 kg. 
According to Mat's Podcast, some sort of wind tunnel tests. It would be nice if Zenair would post a report for the wind tunnel tests. The video that Zenair posted of the GVT on the 650 shows something of what those tests entailed. See



 http://www.youtube.com/watch?v=0VMMVuVrweM



 The wind tunnel tests would be an entirely separate affair. To date I have not seen any report of the wind  tunnel tests nor of the load tests.



 Terry 



 At 08:36 PM 6/17/2009 +0000, you wrote:



 [quote]Ok. I am getting confused again <GG>   Mathieu said  >"the latest thing they've just completed now is a series of flutter tests 

 >in a wind tunnel.



 Is the GVT considered a wind tunnel test or was there two  seperate tests performed ??



 do not archive



 

 Ben Haas

 N801BH

 www.haaspowerair.com



 --------

_________________
Terry Phillips
Corvallis, MT
ttp44<at>rkymtn.net
Zenith 601XL/Jab 3300 slow build kit - Tail feathers done; working on the wings.

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