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Airframe life expectancy

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steveg(at)nternet.com
Guest

Posted: Fri Jan 20, 2006 3:04 pm Post subject: Airframe life expectancy

I forwarded Jim's earlier email to my partner and his response is below.  I

have not had time to review and research as Michael has.  Seems crazy to me

that Oz sees winglets as capable of cutting a Commanders life in half.  My

last AC500 had winglets and other than watching for corrosion at the

connection points and overall body I see no threat.  Just another part of

the aircraft to inspect and maintain.   Any knowledgeable comments

pertaining to Oz.  Is Michael misreading something here??



Steve G



--

BobsV35B(at)aol.com
Guest

Posted: Fri Jan 20, 2006 3:36 pm Post subject: Airframe life expectancy

Good Evening Steve,  



I certainly do not understand why the folks down under want to extract such  

a penalty from those who attempt to improve their flying machines, but may I  

make a comment?

 

Adding winglets should make the outer portion of the wing more efficient.  

Something like a tip plate. Getting a little more lift out there means that the  

center of pressure (lift) moves outboard a bit. Moving the lifting point  

outboard causes a greater bending moment at whatever point the bending  moment is 

calculated. 

 

It appears to me that the people in charge down there are making those  

onerous noises in an effort to force someone to develop data that will show the  

increased bending moment is not great enough to demand cutting the useful life  

in half.

 

Has anyone developed such data?

 

One the other hand:

 

Why not maintain the airplane as a US registered aircraft?  Are we not  

allowed to fly our US registered airplanes in Australia and then use US  standards?

 

Just in case it matters, I do not own a Commander, but I did fly them quite  

a bit forty to fifty years ago. I enjoy your list, but will leave if  asked.

 

Happy  Skies,



Old Bob

AKA

Bob Siegfried

Ancient Aviator

Stearman  N3977A

Brookeridge Air Park LL22

Downers Grove, IL 60516

630  985-8503



 

In a message dated 1/20/2006 5:04:51 P.M. Central Standard Time,  

steveg(at)nternet.com writes:



I  forwarded Jim's earlier email to my partner and his response is below.   I

have not had time to review and research as Michael has.  Seems  crazy to me

that Oz sees winglets as capable of cutting a Commanders life  in half.  My

last AC500 had winglets and other than watching for  corrosion at the

connection points and overall body I see no threat.   Just another part of

the aircraft to inspect and maintain.   Any  knowledgeable comments

pertaining to Oz.  Is Michael misreading  something here??



Steve G

steveg(at)nternet.com
Guest

Posted: Fri Jan 20, 2006 3:56 pm Post subject: Airframe life expectancy

Bob,



Your input and knowledge are invaluable.  I was part owner of AC500 N6291B

with Rob.  Now only own Bonanza E35 N52DF and participate on both lists.

Dream of owning another AC500 and may wind up doing so with my Australian

business associate or may not.  Either way, both lists are full of talented,

knowledgeable people that feed my thirst for aviation knowledge,

particularly involving specific types of aircraft.  You even got me looking

at the new Xerion for my Bonanza the other day.  Might do it!!



Thanks,

Steve G



--

BertBerry1(at)aol.com
Guest

Posted: Fri Jan 20, 2006 4:37 pm Post subject: Airframe life expectancy

I must have missed the whole winglets conversation.  Is that an article 

posted somewhere?



Bert

wjrhamilton(at)optusnet.c
Guest

Posted: Sat Jan 21, 2006 6:50 am Post subject: Airframe life expectancy

Folks,

In  Australia, a large variety of aircraft are subject to locally 

imposed fatigue life limits, they vary from reasonable ( based on the 

record) through illogical to unreasonable, and finally downright crazy.



As to the last, take the Piper Seneca --- It was actually tested in a 

rig by Piper to Australian designed fatigue criteria, (the test was 

very severe, amongst other things zero allowance was made for engine 

or fuel weight for bending relief)  and the test was finally stopped 

at the point where the wing/airframe could be declared "unlimited life" .



Never mind, a severe life was imposed "to be consistent"with other 

aircraft. For pressure hull, don't even start me.



Where a wing is re-spared, the rest of the aircraft is limited to two 

wing lifes. This leads to the wonderful result that a particular 

C-310 fuselage and tail feathers has two lives ( don't quote me on 

the figures, but let us say 14 or 28 thousand hours) depending on the 

wing it is bolted on to!!



The history is interesting, the following is a highly biased summary.



Some years after the end of WW11, there were lots of P-51D wings 

around the place, so about 100 new wings were tested to destruction, 

resulting ( surprise, surprise) in a "bell curve" of failures, and 

the just slightly contestable claim that Australia has discovered 

metal fatigue.



Despite a more or less identical claim by the poms ( English for 

those of you who haven't done a Crocodile Dundee refresher recently) 

as a result of the loss of the "Square window" Comets, and;



  Despite some fascinating stuff even then on the public record about 

Boeing experience with the original 338, and the fact that 

engineering text books put it 100 years or so earlier, in the early 

days of railways, and some bridge collapses.



Compared to any other light twin, the Aero Commander "fatigue AD" 

limits are not generally a big issue, they are 3 or 4 times the "average".



Best regards,

Bill Hamilton





At 10:35 21/01/2006, you wrote:

 	  Quote: 	
		  



Good Evening Steve,



I certainly do not understand why the folks down under want to extract such

a penalty from those who attempt to improve their flying machines, but may I

make a comment?



Adding winglets should make the outer portion of the wing more efficient.

Something like a tip plate. Getting a little more lift out there 

means that the

center of pressure (lift) moves outboard a bit. Moving the lifting point

outboard causes a greater bending moment at whatever point the 

bending  moment is

calculated.



It appears to me that the people in charge down there are making those

onerous noises in an effort to force someone to develop data that 

will show the

increased bending moment is not great enough to demand cutting the 

useful life

in half.



Has anyone developed such data?



One the other hand:



Why not maintain the airplane as a US registered aircraft?  Are we not

allowed to fly our US registered airplanes in Australia and then use 

US  standards?



Just in case it matters, I do not own a Commander, but I did fly them quite

a bit forty to fifty years ago. I enjoy your list, but will leave if  asked.



Happy  Skies,



Old Bob

AKA

Bob Siegfried

Ancient Aviator

Stearman  N3977A

Brookeridge Air Park LL22

Downers Grove, IL 60516

630  985-8503

In a message dated 1/20/2006 5:04:51 P.M. Central Standard Time,

steveg(at)nternet.com writes:



I  forwarded Jim's earlier email to my partner and his response is below.   I

have not had time to review and research as Michael has.  Seems  crazy to me

that Oz sees winglets as capable of cutting a Commanders life  in half.  My

last AC500 had winglets and other than watching for  corrosion at the

connection points and overall body I see no threat.   Just another part of

the aircraft to inspect and maintain.   Any  knowledgeable comments

pertaining to Oz.  Is Michael misreading  something here??



Steve G






	




CONFIDENTIALITY & PRIVILEGE NOTICE

W.J.R.Hamilton,Glenalmond Group Companies,Fighter Flights Internet 

Services and Warbirds.Net. & <wjrhamilton(at)optusnet.com.au>.

This message is intended for and should only be used by the 

addressee. It is confidential and may contain legally privileged 

information.If you are not the intended recipient any use 

distribution,disclosure or copying of this message is strictly 

prohibited.Confidentiality and legal privilege attached to this 

communication are not waived or lost by reason of the mistaken 

delivery to you.If you have received this message in error, please 

notify us immediately to Australia 61 (0)408 876 526

Dolores capitis non fero. Eos do.

deneals

Joined: 09 Jan 2006
Posts: 29

Posted: Sat Jan 21, 2006 7:03 am Post subject: Airframe life expectancy

Thanks, Bill.

As former Chief Pilot for Nomad Distributors in the US, reading your post

about aircraft certifications in Australia makes me wonder....

How the heck did the NOMADS ever get certification!!??

 

___________________________

Deneal Schilmeister

St. Louis - Cincinnati

1997 SL500

http://homepage.mac.com/deneals/SL500.htm

http://homepage.mac.com/deneals/Sites/My_Commanders.htm



--

kamala(at)msn.com
Guest

Posted: Sat Jan 21, 2006 7:30 am Post subject: Airframe life expectancy

suggest that for the technical info on winglets that you go to the source.  

call john bosh at commander aero  888-881-5580.  dick wartinger at commander 

aero developed these winglets, they hold the stc.  also the air force 

engineneers at the air force facility used there wind tunnels and all 

available u s government equipment and computing power to arive at the right 

design for the commander wing.  mason   ps  there are a lot of illegal 

winglets out there!

[quote]From: "steve" <steveg(at)nternet.com>

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

To: <commander-list(at)matronics.com>

Subject: RE: FW: Airframe life expectancy

Date: Fri, 20 Jan 2006 17:55:48 -0600






Bob,



Your input and knowledge are invaluable.  I was part owner of AC500 N6291B

with Rob.  Now only own Bonanza E35 N52DF and participate on both lists.

Dream of owning another AC500 and may wind up doing so with my Australian

business associate or may not.  Either way, both lists are full of 

talented,

knowledgeable people that feed my thirst for aviation knowledge,

particularly involving specific types of aircraft.  You even got me looking

at the new Xerion for my Bonanza the other day.  Might do it!!



Thanks,

Steve G



--

britmonk(at)adelphia.net
Guest

Posted: Sat Jan 21, 2006 2:21 pm Post subject: Airframe life expectancy

I understand that the winglets are purely cosmetic and make no change in 

the aerodynamic characteristics. Thus the BM should not be changed. 

However it only takes about a 10% change in load to half the fatigue 

life of a structure. Perhaps the Ozzies are just playing it safe.

Derek Monk



BobsV35B(at)aol.com wrote:



 	  Quote: 	
		  



 

 

Good Evening Steve,  



I certainly do not understand why the folks down under want to extract such  

a penalty from those who attempt to improve their flying machines, but may I  

make a comment?

 

Adding winglets should make the outer portion of the wing more efficient.  

Something like a tip plate. Getting a little more lift out there means that the  

center of pressure (lift) moves outboard a bit. Moving the lifting point  

outboard causes a greater bending moment at whatever point the bending  moment is 

calculated. 

 

It appears to me that the people in charge down there are making those  

onerous noises in an effort to force someone to develop data that will show the  

increased bending moment is not great enough to demand cutting the useful life  

in half.

 

Has anyone developed such data?

 

One the other hand:

 

Why not maintain the airplane as a US registered aircraft?  Are we not  

allowed to fly our US registered airplanes in Australia and then use US  standards?

 

Just in case it matters, I do not own a Commander, but I did fly them quite  

a bit forty to fifty years ago. I enjoy your list, but will leave if  asked.

 

Happy  Skies,



Old Bob

AKA

Bob Siegfried

Ancient Aviator

Stearman  N3977A

Brookeridge Air Park LL22

Downers Grove, IL 60516

630  985-8503



 

In a message dated 1/20/2006 5:04:51 P.M. Central Standard Time,  

steveg(at)nternet.com writes:



I  forwarded Jim's earlier email to my partner and his response is below.   I

have not had time to review and research as Michael has.  Seems  crazy to me

that Oz sees winglets as capable of cutting a Commanders life  in half.  My

last AC500 had winglets and other than watching for  corrosion at the

connection points and overall body I see no threat.   Just another part of

the aircraft to inspect and maintain.   Any  knowledgeable comments

pertaining to Oz.  Is Michael misreading  something here??



Steve G

nico(at)cybersuperstore.c
Guest

Posted: Sat Jan 21, 2006 4:07 pm Post subject: Airframe life expectancy

Didn't they just feed them kangeroos?



---

nico(at)cybersuperstore.c
Guest

Posted: Sat Jan 21, 2006 4:07 pm Post subject: Airframe life expectancy

My understanding is that winglets inhibit the development of wingtip

vortices, one of the major players in drag. Am I right?



---

BillLeff1(at)aol.com
Guest

Posted: Sun Jan 22, 2006 10:20 pm Post subject: Airframe life expectancy

The Commander Aero Winglet, for the 500S was a copy of the factory tip for  

the 695 series. It was first put on AvFuel's Shrike. It does help low speed 

roll  control bit does nothing for the high end. 

 

It was certified as "no change in performance" to save having to prove the  

numbers. Flutter test were done but no high speed computer modeling was done to 

 my knowledge. The engineers at Wright Patterson did look at them but again, 

to  my knowledge, they only gave an opinion. They did think that they were 

about as  good as you could get without a major re design.

 

They do look good and in my judgment really help low speed activities like  

take off, low speed roll control, maybe even single engine climb. But there is  

nothing to prove it. 

 

Oh Yeah, I did the flight test for Dick.

 

There are some great reports on wing life expectancy floating around, I use  

to have a copy but I cant find it. It showed the fatigue life calculations for 

 the different models based on hours and flight profile cycles. It was really 

 neat. Low altitude aerial survey significantly reduced the life of the  

wing. I also saw the test facility at Norman, OK where they did the cycle life  

test on the 1000. As I remember they bent the wings 33 inches at the tip  and 

pressurized the cabin to 21 psi before the cabin door blew  off!  It was cool!  

When I saw it, they had reached 21K hours and  were still testing.

 

Bill Leff

wjrhamilton(at)optusnet.c
Guest

Posted: Mon Jan 23, 2006 7:02 am Post subject: Airframe life expectancy

Deneal,

Given some of the more endearing characteristics of the Nomad ( not 

to be confused with the North American NA-260 Nomad, the civil 

certified T-28, one R. Hoover, Esq, not entirely unknown to Aero 

Commander or P-51 aficionados, project test pilot)  perhaps a better 

question is "Why was the Nomad certified at all". One characteristic 

it shared with its North American namesake was all the performance of 

a polished crowbar when it all went quiet.



You probably visited the Government Aircraft Factory at Avalon, 

Victoria, the way that place worked, it was quite amazing that the 

aeroplane ever got out the factory door.

Bear in mind that many of the staff , particularly design staff, at 

the GAF, were refugees from the collapse of the British aircraft 

industry, to say the least there was a certain prejudice against 

anything from US, many of the professional engineers in (those days) 

the Department of Civil Aviation were also from the same bulk store.



The fact that "a good solid aeroplane" like the DH Chipmunk has 

severe aircraft life limits, (starting at 5500 hours) and for good 

reasons, never dented the prejudice against spam cans , anything made 

by Piper, Beech or Cessna, despite some C-172 racking up 20,000 plus 

on the original structure. Note, spam here is not what you get every 

time you download your email, but a particularly nasty tinned "meat" 

more properly called Imperial Camp Pie, if my memory serves me 

correctly. My recollection of the 'orrible stuff is very clear, even 

if the name isn't.



The same prejudice was and is displayed against airline aircraft, 

despite the fact that we lost a number of Vickers Viscounts from 

in-flight breakups for various reasons, DH 104 Dove's didn't like 

Australian air at all, all the later Tridents were withdrawn from 

service due fatigue problems,and the story goes on --- but there has 

been no such parallel with DC-3/4/6, 

L-049/749/1049/1049G/L-177/DC-9/B707-138/338/B-747-238/338/438/SP/B-767-238/338 

--- get the drift.



I worked for Qantas for many years, Qantas started international 

services with a dreadful four engine bi-plane, the DH-86A. There are 

none in museums, every single one crashed. The very first Qantas 

aircraft was nearly lost near Cairo on the delivery, flown by a 

Qantas crew. The second delivery, flown by an Imperial Airways crew, 

was lost with all aboard, at Longreach, Queensland. Our major 

competition, KLM, was flying Lockheed14 , DC-2 and DC-3, but the 

operation of US aircraft over "Imperial Routes was banned. This did 

not change until after WW11.



Folks, I hope you are not bored with all this, its not much to do 

with Commanders, but you see what happens when somebody gets me 

started, but at least Bob Hoover rated a mention.'



Cheers,

Bill Hamilton

At 02:03 22/01/2006, you wrote:

 	  Quote: 	
		  

(Portege)" <deneals(at)sbcglobal.net>



Thanks, Bill.

As former Chief Pilot for Nomad Distributors in the US, reading your post

about aircraft certifications in Australia makes me wonder....

How the heck did the NOMADS ever get certification!!??



___________________________

Deneal Schilmeister

St. Louis - Cincinnati

1997 SL500

http://homepage.mac.com/deneals/SL500.htm

http://homepage.mac.com/deneals/Sites/My_Commanders.htm

CONFIDENTIALITY & PRIVILEGE NOTICE
	


W.J.R.Hamilton,Glenalmond Group Companies,Fighter Flights Internet 

Services and Warbirds.Net. & <wjrhamilton(at)optusnet.com.au>.

This message is intended for and should only be used by the 

addressee. It is confidential and may contain legally privileged 

information.If you are not the intended recipient any use 

distribution,disclosure or copying of this message is strictly 

prohibited.Confidentiality and legal privilege attached to this 

communication are not waived or lost by reason of the mistaken 

delivery to you.If you have received this message in error, please 

notify us immediately to Australia 61 (0)408 876 526

Dolores capitis non fero. Eos do.

britmonk(at)adelphia.net
Guest

Posted: Tue Jan 24, 2006 10:04 pm Post subject: Airframe life expectancy

Nico,

The wingtip vortex causes a downflow on the wing tip which reduces lift. 

To maintain the necessary lift the wing AOA has to be increased thus 

increasing the wing drag. The properly designed (and tested) winglet 

will minimize the downflow thus increasing the lift at the outer wing. 

Thus less AOA is needed, hence lower drag. Some people look at it as an 

effective increase in wing span, i.e. wing efficiency.



css nico wrote:



[quote]



My understanding is that winglets inhibit the development of wingtip

vortices, one of the major players in drag. Am I right?



---

n395v

Joined: 10 Jan 2006
Posts: 450

Posted: Wed Jan 25, 2006 5:46 am Post subject: Re: Airframe life expectancy

 	  nico(at)cybersuperstore.c wrote: 	
		  My understanding is that winglets inhibit the development of wingtip

vortices, one of the major players in drag. Am I right?



--- 	




Nico,



That is correct go to the link below and look at page 12 of the PDF file

http://www.commander-aero.com/image/Cat04.pdf



Interestingly it does not increase lift so should not affect fatigue life of the wing.

_________________
Milt

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