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Wing drop in the stall

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BEBERRY(at)aol.com
Guest

Posted: Sat Jul 29, 2006 12:33 am Post subject: Wing drop in the stall

All the recent correspondence following the tragedy at Oshkosh seems to  point to a basic instability with the Europa. Is this inherent in the design or  due to building errors?

  

 Trimming ailerons to achieve smooth integration with the wing profile is  dodgy and may point to a basic error in construction with one wing having a  different lift characteristic to the other.  The descriptions of other  incidents such as a very sudden wing drop and incipient spin are not  asociated with any other GA or home build as far as I know. 

  

 Questions.. do people's experiences of wing drops apply generally in the  same manner or do they apply to different wings and perhaps mainly to the foam  wing?  

  

 Should there be improved ways of measuring the newly formed wing profile  before finishing?

  

 Have any pilots flown different Europas to see if the problem is  replicated?

  

 I have never known a severe - or even comparatively slight wing drop in the  stall, power on or off, in GA aircraft  so the apparent Europa problem is  worrying and needs some more in depth investigation. 

  

 Patrick

n9zes(at)verizon.net
Guest

Posted: Sat Jul 29, 2006 5:27 am Post subject: Wing drop in the stall

=====================



All the recent correspondence following the tragedy at Oshkosh seems to point to a basic instability with the Europa. Is this inherent in the design or due to building errors? Trimming ailerons to achieve smooth integration with the wing profile is dodgy and may point to a basic error in construction with one wing having a different lift characteristic to the other.  The descriptions of other incidents such as a very sudden wing drop and incipient spin are not asociated with any other GA or home build as far as I know.  



--->  I don't know about others, but I've flown several C-152's with some pretty nasty wing drops at stall.  One in particular would almost always drop a wing down at least 60 degrees and need full rudder to pick it up.  Aside from that, it was the best flying out of the 4 at the FBO I trained at.  If not paying attention and really being on top of the plane, an inadvertent stall would put you on your back, fast.



In contrast, our C-140 wouldn't drop a wing unless deliberately crossed up.  I've not spun it yet, but I have a hard enough time just getting a stall out of it, with the fuselage banging like an old beer can the whole time from the buffeting.  Big pussy cat.



Chris

gcrowder2

Joined: 09 Jan 2006
Posts: 136
Location: Golden, Colorado USA

Posted: Sat Jul 29, 2006 7:10 am Post subject: Wing drop in the stall

I fly with the foam wing on my aircraft at high density altitudes (8500 

MSL yesterday) and

at gross weights (pilot 220 lbs, passenger 200 lbs, Subaru engine) and have 

have never had

a wing drop at any time unless doing intentional stalls.  My wing only has a 

mild 30 degree

drop to the left and indicates no  tendency to roll under.  I also have no 

stall strips.



                                               Glenn

 	  Quote: 	
		  From: BEBERRY(at)aol.com

Reply-To: europa-list(at)matronics.com

To: europa-list(at)matronics.com

Subject: Re: Wing drop in the stall

Date: Sat, 29 Jul 2006 04:32:13 EDT



All the recent correspondence following the tragedy at Oshkosh seems to

point to a basic instability with the Europa. Is this inherent in the 

design or

due to building errors?



Trimming ailerons to achieve smooth integration with the wing profile is

dodgy and may point to a basic error in construction with one wing having a

different lift characteristic to the other.  The descriptions of other  

incidents

such as a very sudden wing drop and incipient spin are not  asociated with 

any

other GA or home build as far as I know.



Questions.. do people's experiences of wing drops apply generally in the

same manner or do they apply to different wings and perhaps mainly to the 

foam

wing?



Should there be improved ways of measuring the newly formed wing profile

before finishing?



Have any pilots flown different Europas to see if the problem is  

replicated?



I have never known a severe - or even comparatively slight wing drop in the

stall, power on or off, in GA aircraft  so the apparent Europa problem is

worrying and needs some more in depth investigation.



Patrick

carl(at)flyers.freeserve.
Guest

Posted: Sat Jul 29, 2006 7:23 am Post subject: Wing drop in the stall

The Europa is no more or less unstable than other aircraft but it is a 

kitplane so there will be variations between different aircraft.



The problem of  the wing dropping in the stall was identified early on by 

Europa and the PFA and is easily resolved by the fitting of stall strips. In 

the UK stall strips or a stall warner are a mandatory fitment to all Europa 

aircraft. I am pretty certain that if you look in your builders/ pilots 

manual you will find a passage relating to testing and setting this up.



 The stall strips are fitted in such a way that both wings stall at the same 

time which eliminates the tendency to drop a wing.



 Stall strips are a common fitment to kitplanes and GA aircraft alike. Next 

time you walk past a line of aircraft, take a look.



 To suggest that this is a Europa specific problem is nonsense.



BTW the most likely cause of a wing drop in the first place is a 

misalignment of the flaps which I would imagine is rather difficult to 

correct. Far easier to fit the strips or a stall warner.

[quote] ---

asarangan(at)yahoo.com
Guest

Posted: Sat Jul 29, 2006 11:07 am Post subject: Wing drop in the stall

Anyone know how much extra drag the stall strips add?

mikenjulie.parkin(at)btop
Guest

Posted: Sat Jul 29, 2006 12:18 pm Post subject: Wing drop in the stall

Patrick,

  

 I understand that you bought your aircraft part built.  If you had  built the foam wings you would understand why the aircraft flight  characteristics can vary a little.

  

 I think that with the foam wings, the chance of each wing having a  different lift characteristic is an ocean going certainty.  Dodgy or not,  adjusting the ailerons to be in the correct position when wingborne solved  a potentially dangerous stall characteristic on my Europa.  I was  passing on an experience that worked well for my aircraft, it was not intended  as a panacea for all stalling problems.

  

 Incidentally, a wing drop at the stall is a common feature in  many  aircraft, GA or homebuilt.  As Carl pointed out, adjusting the flaps is  often a solution.  I have seen this done on a couple of Cessnas.  The  correct fitting of stall strips to the Europa is the recommended procedure for  taming an 'interesting' stall characteristic.  Stall strips are common to  many aircraft including twins, twin jets as well.

  

 A Falcon 20 I recently tested had a very exciting wing drop, and  was eventually sorted by  adjustment of the leading edge droop.

  

 There is nothing inherently wrong with the Europa and it certainly does not  suffer from any basic instability - it just needs to be set up properly by  an able test pilot who understands how to adjust the stall strips.

  

 Have you actually flown in a Europa?

  

 regards,

  

 Mike

  

  

 Do not archive.

 [quote]   ---

BEBERRY(at)aol.com
Guest

Posted: Sat Jul 29, 2006 1:02 pm Post subject: Wing drop in the stall

In a message dated 29/07/2006 21:19:22 GMT Daylight Time,  mikenjulie.parkin(at)btopenworld.com writes:

  	  Quote: 	
		     Incidentally, a wing drop at the stall is a common feature in  many    aircraft, GA or homebuilt.  As Carl pointed out, adjusting the flaps is    often a solution.  I have seen this done on a couple of Cessnas.     The correct fitting of stall strips to the Europa is the recommended procedure    for taming an 'interesting' stall characteristic.  Stall strips are    common to many aircraft including twins, twin jets as well.

    

	


 

 Mike - thanks for your comments - when I talked about wing drop at the  stall I was referring to the dramatic results experienced by some correspondents  e.g. violent drop and even inversion.  I have relatively little Europa  experience and have not attempted deliberate stalling but have done so with  other types and wing drop has been nil or very gentle.

  

 I shall be looking again at stall strips.

  

 Patrick

mikenjulie.parkin(at)btop
Guest

Posted: Sun Jul 30, 2006 8:44 am Post subject: Wing drop in the stall

 	  Quote: 	
		  Are the Classics more prone to wing drop?  Do XS wings have the same 

behavior?  Could a minor tolerance between the wing setup (angle of 

 >attack, sweep) be a cause of wing drop in stall? Do i understand correctly 

that stall strips are spoiling the good wing to the same quality as the bad 

 >wing? In what class are the speed penalties involved?


	




Jos,



I think that the original foam built wings are likely to vary slightly more 

in performance than the factory made wings purely  because of the nature of 

construction.  Profiling the wing is a laborious process and the end result 

is very much an 'eyeball dependent' operation.  I think it would be fair to 

say that the jig made factory wings are likely to produce a more consistent 

result.

The original wings were fitted with flaps and ailerons made from foam 

blocks, glass cloth and resin.  Fitting the flap hinges and setting up the 

correct washout was challenging and certainly not a precise science.  Having 

produced 2 of these labour intensive wings, the chances of each wing 

exhibiting the same CL curve is unlikely at best.  Combine these variables 

with any tolerances in the wing to fuselage incidence and you could have 

some work to do to make the aircraft behave.  The very nature of the wing 

seems to provide a useable amount of lift until the stall, at which point 

the loss of lift from the wing seems to be almost total.  Now if one wing 

stalls before the other it is conceivable that the aircraft might roll on 

its back.

The purpose of the stall strips is exactly as you suggest - to make the good 

wing stall before it would if the stall strip was not fitted.



I think that the strip works by the nib of the strip disrupting the boundary 

layer (at particulat angle of attack)  on the wing downstream of the strip. 

I have read somewhere that the strips can affect short field landing and 

take-off performance - no doubt one of our aerodynamicists would be able to 

explain - I can't remember the reason.



However, as I understand it, the stall strips have negligible effect at 

higher speeds.



level busts, the subject of stabilised approaches is very topical with 

training captains.  All pilots should strive to establish a stabilised 

approach (on calculated landing speed, on the centreline, on glidepath, 

sensible power setting) by 200 - 300 ft finals.  If you have not achieved 

the ideal situation then consider going around and getting it right next 

time.  There is no loss off face by throwing away a poor approach - anyone 

that thinks there is, is just 'flying towards the scene of his own 

accident'.  All pilots should know when to throw it away - and particularly 

with inexperienced or non-current pilots - it should be sooner rather than 

later.



Remember the old fighter pilot saying - height is might and speed is life.

All the best, and safe flying.



regards,



Mike

nwcmc(at)tiscali.co.uk
Guest

Posted: Sun Jul 30, 2006 9:52 am Post subject: Wing drop in the stall

I don't know but they certainly increase stall speed so there is no gain

without pain. My Europa only seems to exhibit significant wing drop in

an accelerated stall. I was therefore able to just fit a stall warner

rather than stall strips as well avoiding raising the stall speed.



Nigel Charles



--

bryan(at)blackballclub.co
Guest

Posted: Sun Jul 30, 2006 11:49 am Post subject: Wing drop in the stall

Regarding your question. "do XS wings have the same behaviour?"



In 1998 I had my free demonstration flight prior to purchasing my kit (360). 

Ivan was the demo pilot for the day. Interestingly, he told me that mine was 

the sixth kit purchase of the day, but that is beside the point.



It so happened that it was the first week of selling the XS instead of the 

Classic as it bacame known. Ivan was really keen to show the benign nature 

of the stal characteristics with the XS wing. He set the airspeed to stall 

with power on, and with hands off he allowed the aircraft fly on just using 

rudder. amazingly it flew level, nodding it's way through stall and 

recovery, as he gently navigated in gentle turns just using rudder. He did 

this with and without flap.



Try that with a Cessna!......No don't! In fact he did advise me not to try 

it myself.



I was completely sold. Subsequent experience over the last six years has 

confirmed the stall qualities of the XS to me. I stall it frequently for the 

fun of it and the practice. I can honestly say that I have never had a wing 

drop, and I can fly in the stall condition, but I would not attempt any 

turns whilst doing it.



---

ami(at)mcfadyean.freeserv
Guest

Posted: Sun Jul 30, 2006 12:53 pm Post subject: Wing drop in the stall

Mine will do that with a Classic wing, but with power OFF (and it helps if 

the

CG is well forward)!

But then the Classic has more washout.

However, if some rudder is booted in or if in turbulent conditions, then the

effect is very much like that of a Tomahawk i.e spin entry, which can then

be controlled very quickly (if it is has been anticipated!!).



Duncan McF.

---

NevEyre(at)aol.com
Guest

Posted: Sun Jul 30, 2006 1:00 pm Post subject: Wing drop in the stall

In a message dated 30/07/2006 21:54:43 GMT Standard Time,  ami(at)mcfadyean.freeserve.co.uk writes:

  	  Quote: 	
		  But then    the Classic has more washout.

	


 

 The Classic had 1.5 degree washout, the XS HAS 2.5 DEGREES WASHOUT

 Cheers,

 Nev.

NevEyre(at)aol.com
Guest

Posted: Sun Jul 30, 2006 2:37 pm Post subject: Wing drop in the stall

In a message dated 29/07/2006 09:35:07 GMT Standard Time, BEBERRY(at)aol.com  writes:

  	  Quote: 	
		     I have never known a severe - or even comparatively slight wing drop in    the stall, power on or off, in GA aircraft  so the apparent Europa    problem is worrying and needs some more in depth investigation. 

    

   Patrick

    

    

	


 

 Hi Patrick,

 There is no problem with the DESIGN of the Europa, but each individual  aircraft needs to be test flown, and individually set up with regard to any  stall strip fitment / adjustment.

 For your information / peace of mind, I was involved with the test flights  of the Europa you have purchased, and although it may look like a piece of s**t,  it is very light, and true, and the stall [ or rather , lack of,] is one of the  most benign I have experienced. Power on stalls just do not happen, unless you  are totally asleep, at full throttle, [ 100 percent ] stick fully back, it  just ''nods'' and maintains height. I have flown a full circuit at  Wombleton [ at 3000 ' ] at full power / stick full aft, keep the ball in  the middle and your eye on the temps...... you could do that all day........  power off was equally a non event, nose falls through 20 degrees /  lose 50  feet. 

 Enjoy.......

 Cheers,

 Nev.

carl(at)flyers.freeserve.
Guest

Posted: Sun Jul 30, 2006 11:30 pm Post subject: Wing drop in the stall

Hear hear Nev !!!!!

  

 The fact is that many Europa owners are ex military/ professional pilots.  If there was a significant design fault/ problem we would have heard by  now.

  

 Like any other manufactured aircraft, GA or Kitplane it needs to be test  flown to eliminate the bugs. Even commercial jets which are manufactured to very  fine tolerances will exhibit small differences in their flying  charcteristics.

  

 The Europa record speaks for itself. Over 15 years in production ad over  1000 aircraft sold (ie: kits) and this accident is the FIRST one  of it's kind.

  

 Dont bother investigating a problem that dosent exist. Just make sure the  aircraft is set up properly in the first place.

  

  

 [quote]   ---

BEBERRY(at)aol.com
Guest

Posted: Sun Jul 30, 2006 11:55 pm Post subject: Wing drop in the stall

Nev,

  

 Grateful thanks for your message re G PUDS which has set my mind at  rest.  I have had little opportunity to actually fly the  aircraft since last year as I have been away abroad a good deal of the  time and have spent much time (and money!) doing a complete renovation ,  including paint, Arplast prop, complete new interior inc. purpose made seats,  speed kit, etc.  Now awaiting Pete Jeffers to call and arrange  inspection and Test flights.

  

 Unfortunately, in the meantime my wife has suffered a severe injury which  will mean that she is unlikely to regain full use of her left arm and the  likeliehood of her being able to access and egress the a/c is slim.  I may  have to completely re-think our flying in the future so G PUDS may well appear  on the market in due course.

  

 Best wishes,

  

 Patrick

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