acjbbj
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Engine spinner pattern question

Fri Jan 04, 2019 12:18 am

When ordering a plane, is it possible to request a specific pattern of paibt on the engine spinner cones?

For example, the A333's CF6-80E1 normally have short spirals ("G swirls"), but is it possible to request the "wobbly crescent" style spinner (off-centre circle with a stripe on the outside) that GE put on the 763ER's CF6-80C2 on the 80E1?
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426Shadow
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Re: Engine spinner pattern question

Fri Jan 04, 2019 1:40 am

You mean can you put like a smiley face or something on it?
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Starlionblue
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Re: Engine spinner pattern question

Fri Jan 04, 2019 3:22 am

426Shadow wrote:
You mean can you put like a smiley face or something on it?


That would be awesome.

Also, it would probably require certification involving a pile of paperwork as high as the spinner from the ground. :D
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WPvsMW
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Re: Engine spinner pattern question

Fri Jan 04, 2019 5:29 am

Factoid... spinner swirls started with the Messerschmitt Bf-109 (or more generally, the Luftwaffe).
https://commons.wikimedia.org/wiki/File ... _G10_1.jpg
https://upload.wikimedia.org/wikipedia/ ... _Ju_87.jpg
https://aerosavvy.com/aircraft-engine-spirals/

I'm waiting for Wi..... to correct me. ;)

I'm not aware of any reg that requires spinner swirls/hashes. Engine makers tend to stick to a single design... trade dress, as it were.
Rollers: thin spiral
GE: thick spiral
PW: hash aka rectangle
https://www.quora.com/How-can-visually- ... l-airplane
 
acjbbj
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Re: Engine spinner pattern question

Fri Jan 04, 2019 8:32 am

Starlionblue wrote:
Also, it would probably require certification involving a pile of paperwork as high as the spinner from the ground. :D


It's just some white paint on the spinner cone.
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Starlionblue
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Re: Engine spinner pattern question

Fri Jan 04, 2019 8:40 am

acjbbj wrote:
Starlionblue wrote:
Also, it would probably require certification involving a pile of paperwork as high as the spinner from the ground. :D


It's just some white paint on the spinner cone.


I know. I was being facetious.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
stratclub
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Re: Engine spinner pattern question

Fri Jan 04, 2019 9:01 am

But not really all that facetious. I could just imagine the amount of engineering data involved in validating a different spinner paint scheme. Even though the change might be pretty close to irrelevant, you would still have to validate the change as being airworthy to the FAA......
 
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Re: Engine spinner pattern question

Fri Jan 04, 2019 9:16 am

Most people won’t understand me, but I swear there is one spinner design that looks like a bass clef when spinning......

Google “bass clef” if you don’t know what I’m talking about)
And this, ladies and gentlemen, is the very first Fokker airplane built in the world. The Dutch call it the mother Fokker.
 
acjbbj
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Re: Engine spinner pattern question

Fri Jan 04, 2019 9:45 am

Flyingdevil737 wrote:
Most people won’t understand me, but I swear there is one spinner design that looks like a bass clef when spinning......

Google “bass clef” if you don’t know what I’m talking about)


Are those the GE "Comma" spirals?
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Apprentice
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Re: Engine spinner pattern question

Fri Jan 04, 2019 10:39 am

Good Morning:
I don’t believe You may change Engine spinner pattern.
It is designed and approved by authorities to “Scare birds”.

Rgds
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fr8mech
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Re: Engine spinner pattern question

Fri Jan 04, 2019 10:44 am

Apprentice wrote:
Good Morning:
I don’t believe You may change Engine spinner pattern.
It is designed and approved by authorities to “Scare birds”.

Rgds


No, the design does not exist to "scare birds". It exists to warn ground personnel that the engine is turning.

https://aerosavvy.com/aircraft-engine-spirals/

https://blog.klm.com/whats-that-comma-d ... at-engine/

https://interestingengineering.com/here ... ks-on-them
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WPvsMW
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Re: Engine spinner pattern question

Fri Jan 04, 2019 10:51 am

"Scaring birds" with spinner patterns is an avgeek myth. No scientific proof. Rollers once said in marketing materials that its thin sprial scared birds. NH painted "wobbly eyeballs" on its spinners.

Spinner patterns are for ground crew, esp. the marshaller, to manage induction risk. Upon entry into a gate (stand), typically when the marshaller can see a pattern instead of a blur on the spinners, the marshaller signals "insert wheel chocks".
 
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Re: Engine spinner pattern question

Fri Jan 04, 2019 10:56 am

Hello: thank You for correcting me.
But, If Spinners pattern are designed to alert people, still I believe it will no easy to change it.
Rgds
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fr8mech
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Re: Engine spinner pattern question

Fri Jan 04, 2019 11:09 am

Apprentice wrote:
Hello: thank You for correcting me.
But, If Spinners pattern are designed to alert people, still I believe it will no easy to change it.
Rgds



Yeah, I'm not too sure about that. I just checked the AMM inspection criteria on each of our aircraft and found absolutely nothing about the pattern painted on the spinner or cap. The tightest limits were for our PW4000 engines, but didn't talk about the pattern at all...just the paint.

Just for giggles, I pulled a CF6 cone from stock...actually, just visited the stock location, because it's big, and it was black. No pattern at all.
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Apprentice
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Re: Engine spinner pattern question

Fri Jan 04, 2019 1:21 pm

Fr8mech, Good Morning, And now about maintenance, is thee any Mx limitation about spinners’ patterns, that imply to R/R it?
I have even do not think about.

Rgds
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JayinKitsap
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Re: Engine spinner pattern question

Fri Jan 04, 2019 6:31 pm

The weight of the paint used for the spinner needs to be dynamically balanced, just like blades need to be replaced in pairs opposite each other. 1 gram of paint imbalance at 10 cm is a very large torque when rotating at 4,000+ RPM.

Balance is also important on control surfaces, the reason why they are painted before the FAL, must have the right balance.
 
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Re: Engine spinner pattern question

Fri Jan 04, 2019 7:34 pm

WPvsMW wrote:
Spinner patterns are for ground crew, esp. the marshaller, to manage induction risk. Upon entry into a gate (stand), typically when the marshaller can see a pattern instead of a blur on the spinners, the marshaller signals "insert wheel chocks".

I think they look at the beacon for that? Especially tricky on single engine taxi, one side might be turning slowly with the other one very much alive.
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7BOEING7
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Re: Engine spinner pattern question

Fri Jan 04, 2019 8:35 pm

I wouldn't completely discount the "scaring birds" use completely.

Japan's All-Nippon Airways has discovered that by menacing-looking eyes painted on the engine intakes of its jet aircraft frighten away birds and prevent collisions.
The magazine International Wildlife reports that in a controlled experiment, the Japanese domestic airline painted eyes on 26 of its Boeing 747's and 767's, and left the rest of its fleet without the bogus eyes.
At the end of the one-year test period, an average of only one bird had hit each of the engines adorned with painted eyes. Each unpainted engine, however, had been struck by an average of nine birds.
All-Nippon Airways estimates that the reduction in bird strikes during the testing period reduced the damage to its aircraft from $910,000 to $720,000. Consequently, All-Nippon plans to paint eyes on all its large-body aircraft.
 
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Re: Engine spinner pattern question

Fri Jan 04, 2019 8:44 pm

WPvsMW wrote:
"Scaring birds" with spinner patterns is an avgeek myth. No scientific proof. Rollers once said in marketing materials that its thin sprial scared birds. NH painted "wobbly eyeballs" on its spinners.

Spinner patterns are for ground crew, esp. the marshaller, to manage induction risk. Upon entry into a gate (stand), typically when the marshaller can see a pattern instead of a blur on the spinners, the marshaller signals "insert wheel chocks".

What exactly are you "inserting" wheel chocks into? do you mean placing chocks and inserting gear pins? If engines are running, you do not go anywhere near the aircraft until you hear the change in sound when engines are shut down. If one engine is shut down before arrival to the gate, the fact that it is not turning or windmilling where you can see individual fan blades if there is any wind validates the fact that it is shut down.

The only reason for patterns painted on the spinners is for brand identity.
 
acjbbj
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Re: Engine spinner pattern question

Fri Jan 04, 2019 9:06 pm

Yep. (1 gram) * (10 cm) * (3496 rpm)^2 = 3.013 lbf
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747Whale
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Re: Engine spinner pattern question

Fri Jan 04, 2019 9:24 pm

Apprentice wrote:
Good Morning:
I don’t believe You may change Engine spinner pattern.
It is designed and approved by authorities to “Scare birds”.

Rgds


Not remotely true.
 
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Re: Engine spinner pattern question

Fri Jan 04, 2019 10:02 pm

Might be sorta true, but not because of bird strike prevention. Manufacturers might have the spinner marking graphic and color written into the TC (Type Certificate) for brand recognition purposes. How would a blurred spinner scare off birds? Especially if the birds might not even be looking in the direction of a departing aircraft?

Nothing here about bird strike prevention by specific graphics painted on a spinner.
https://en.wikipedia.org/wiki/Bird_strike
Last edited by stratclub on Fri Jan 04, 2019 10:15 pm, edited 3 times in total.
 
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Re: Engine spinner pattern question

Fri Jan 04, 2019 10:04 pm

The purpose of marking the spinner is to indicate engine rotation.

It has nothing to do with frightening birds.
 
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Flyingdevil737
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Re: Engine spinner pattern question

Fri Jan 04, 2019 10:20 pm

acjbbj wrote:
Flyingdevil737 wrote:
Most people won’t understand me, but I swear there is one spinner design that looks like a bass clef when spinning......

Google “bass clef” if you don’t know what I’m talking about)


Are those the GE "Comma" spirals?


Yes, that’s the one!

Thanks
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Re: Engine spinner pattern question

Fri Jan 04, 2019 10:24 pm

747Whale wrote:
The purpose of marking the spinner is to indicate engine rotation.

It has nothing to do with frightening birds.


I guess the ANA study was a non-event then. Nothing like a closed mind.
 
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Re: Engine spinner pattern question

Fri Jan 04, 2019 10:53 pm

stratclub wrote:
What exactly are you "inserting" wheel chocks into? do you mean placing chocks and inserting gear pins?


Perhaps you didn't use the IATA publication, "Marshalling Signals", when you were trained. Note the signal, "Insert chocks".
https://www.pinterest.com/pin/165014773816467145
https://www.iata.org/publications/store ... gnals.aspx
 
WPvsMW
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Re: Engine spinner pattern question

Fri Jan 04, 2019 10:55 pm

7BOEING7 wrote:
747Whale wrote:
The purpose of marking the spinner is to indicate engine rotation.

It has nothing to do with frightening birds.


I guess the ANA study was a non-event then. Nothing like a closed mind.


NH discontinued the "wobbly eye" spinner pattern. Results were statistically inconclusive. Cost/benefit was negative. Reverted to "manufactuer's pattern".
Here's an NH B789 "Doraemon" with thin spirals (therefore, a Rollers Trent 1000)
https://www.airliners.net/photo/All-Nipp ... AkmXLpE%3D
and a magnificent NH A388 "Honu" (Rollers Trent 900)
https://www.airliners.net/photo/All-Nipp ... vnpaLuc%3D
 
747Whale
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Re: Engine spinner pattern question

Sat Jan 05, 2019 12:31 am

7BOEING7 wrote:
747Whale wrote:
The purpose of marking the spinner is to indicate engine rotation.

It has nothing to do with frightening birds.


I guess the ANA study was a non-event then. Nothing like a closed mind.


ANA neither invented markings on turbine spinners, nor continued the questionable program they started.

The quote you provided, plagiarized without citation, was taken from a New York times article in 1986.

Nothing like actually lifting a finger to cite your quote or provide a link, or actually reading it to find out it's over 30 years out of date, mate.

Nicely done, but at least you've got an "open mind."

An "open mind" doesn't change the fact that markings on spinners were not created to scare off wildlife, but to give a visual indication of rotation.
 
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fr8mech
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Re: Engine spinner pattern question

Sat Jan 05, 2019 1:19 am

Apprentice wrote:
Fr8mech, Good Morning, And now about maintenance, is thee any Mx limitation about spinners’ patterns, that imply to R/R it?
I have even do not think about.

Rgds


As I wrote earlier, our AMM does not mention the paint pattern at all. The PW4000 has a limit of 50% of the paint missing. That's it when it comes to the paint.

As I also mentioned, the CF6 spinner I looked at did NOT have a pattern painted on it. I'd go look at a PW4000 cone, but we stock those at a remote location.
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7BOEING7
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Re: Engine spinner pattern question

Sat Jan 05, 2019 1:56 am

747Whale wrote:
7BOEING7 wrote:
747Whale wrote:
The purpose of marking the spinner is to indicate engine rotation.

It has nothing to do with frightening birds.


I guess the ANA study was a non-event then. Nothing like a closed mind.


ANA neither invented markings on turbine spinners, nor continued the questionable program they started.

The quote you provided, plagiarized without citation, was taken from a New York times article in 1986.

Nothing like actually lifting a finger to cite your quote or provide a link, or actually reading it to find out it's over 30 years out of date, mate.

Nicely done, but at least you've got an "open mind."

An "open mind" doesn't change the fact that markings on spinners were not created to scare off wildlife, but to give a visual indication of rotation.


Ok, I didn't document properly but .....

The data provided is interesting (if accurate) and ....

IIRC, it was almost 40 years ago when I walked out to fly an ANA 747 and noticed the spinner markings, which stood out because they were the only ones on the flight line that had them (and there were lots of 747's on the flight line then). After the flight we asked the customer about them and the answer was to prevent bird strikes. In my carrer in aviation I never heard the alternative explanation but I agree it makes sense.

I never said ANA invented the markings and the fact that the information provided is 30 years old is irrelevant. If you have a link providing information on ANA's discontinuance of the program I'd like to read it.
 
747Whale
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Re: Engine spinner pattern question

Sat Jan 05, 2019 2:57 am

Find it yourself.

Links were posted above with recent pictues of ANA aircraft without "eyes" on spinners.

Given the goofy paint schemes, I wouldn't hold them up as the cutting edge of any paint scheme.

How you could have missed the basic understanding of visual markings to show rotation on turbine engines over the past 40-50 years or more is a head-scratcher. It's common knowledge. It's been that way for a very long time.

You'll note that the rest of the world doesn't paint eyeballs on their airplanes to ward off birds.

Then again, there's still a very old wive's tale that weather radar dispels birds, too. The myths live on.
 
WPvsMW
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Re: Engine spinner pattern question

Sat Jan 05, 2019 3:13 am

IIRC, NH never published "we discontinued the wobbly eyes", they just stopped ordering the spinners painted with wobbly eyes. IMO, the wobbly eye was a PR stunt... just like the Star Wars and manga character paint jobs.
 
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Re: Engine spinner pattern question

Sat Jan 05, 2019 3:37 am

WPvsMW wrote:
stratclub wrote:
What exactly are you "inserting" wheel chocks into? do you mean placing chocks and inserting gear pins?


Perhaps you didn't use the IATA publication, "Marshalling Signals", when you were trained. Note the signal, "Insert chocks".
https://www.pinterest.com/pin/165014773816467145
https://www.iata.org/publications/store ... gnals.aspx

Sorry just rattling your cage a little. I stand corrected. We had Marshalling recertification every 2 years and I would always opt out to the skill assessment after having taken the online training several times.

Did you notice that the graphic for "SLOW DOWN LEFT ENGINE" the marshaller is indicating the right engine? When would you use such a signal anyway?
 
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Re: Engine spinner pattern question

Sat Jan 05, 2019 4:31 am

When the right engine is missing?
 
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Re: Engine spinner pattern question

Sat Jan 05, 2019 5:53 am

WPvsMW wrote:
When the right engine is missing?

Why would the marshaller gesture to slow down an engine that had departed the aircraft? My point is that the labels on the graphics for slow down left and right engines are reversed.

Still, I can't think of a time you would direct the pilot to slow down just one engine or engines on one side of the aircraft. On an icy ramp and the nose gear is being pushed sideways because of a slope in the ramp or a side wind maybe?
 
WPvsMW
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Re: Engine spinner pattern question

Sat Jan 05, 2019 5:55 am

Slowing down a missing engine is more humourous than an IATA typo. An IATA typo, in fact, is chilling, rather than humourous.
 
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CALTECH
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Re: Engine spinner pattern question

Sat Jan 05, 2019 2:03 pm

http://www.boeing.com/commercial/aeroma ... ticle4.pdf
' these misconceptions include:

■■ birds don’t fly at night.
■■ birds don’t fly in poor visibility, such as
in clouds, fog, rain, or snow.
■■ birds can detect airplane landing lights
and weather radar and avoid the airplane.
■■ airplane colors and jet engine spinner
markings help to repel birds.
■■ birds seek to avoid airplanes because
of aerodynamic and engine noise.
■■ birds dive to avoid an approaching
airplane.
in fact, none of these statements is
scientifically proven.'

https://blog.klm.com/whats-that-comma-d ... at-engine/
What about the birds?
It’s not a scientifically proven fact, but the spiral may also encourage birds to fly clear of the engine during taxiing, take-off and landing. Instead of a black hole, they see the spinning spiral as a white disk, which might warn them to get away from the black hole that would lead to their untimely demise.

Several studies have been done, but none have been conclusive. Boeing and Rolls Royce, for example, say the spiral does not prevent birds from flying into the engine, as the rotation would be too fast for the birds to see the spiral. Other studies have suggested painting spiral shapes on the spinner cones do help prevent bird strikes. I guess the answer to this question can only be “maybe”, at this point. If only we could ask a bird:)
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747Whale
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Re: Engine spinner pattern question

Sun Jan 06, 2019 4:38 am

I've got a lot of experience with birds, and have had thousands of bird strikes...most of them while spraying crops at low altitudes. Most of those were flocks of birds that would be settled in the crop, and which flew into the air when disturbed by the airplane. Because we fly at low altitudes, our sound footprint is somewhat reduced; the birds often don't respond until nearly on top of them, then rise up out of the crop enmass as we fly through them. I used to call them "popcorn birds" because that's the sound they made hitting the airframe. Typically small birds, they did little damage, most of the time, but occasionally penetrated the leading edge or a canopy, and I've had them explode in the cockpit when they entered the air vent. I saw a lot of them hit the cutter blade on the windscreen and split in two. They were often stuffed in the automatic flagman ram air inlet, and in every other part of the airplane imaginable: wrapped around spray booms, stuffed in the brakes, everywhere.

I can unequivocally say that birds will dive whenever possible to get out of the way. I've seen it untold times. I've also been hit by birds diving from above that tried to get out of the way, sometimes with damage. I struck a peregrine falcon in a 210, peeling the wing back to the spar.

As for birds at night, I had the radome and windscreen shattered by a bird at night, around one in the morning, in a Lear 35. I had similar damage in a Cessna 182, about the same time of night, and same altitude; about 10,000'.

Birds will seek to avoid airplanes and will respond to the noise; often they succeed, sometimes they don't.

I have encountered birds in IMC on several occasions.
 
tepidhalibut
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Re: Engine spinner pattern question

Mon Jan 07, 2019 9:17 am

If I may speak from inside one of the Big Three EngCo's... (But not on their behalf.)

The stripe / spiral provides a better indication of fan rotation, especially useful on the ground / in poor light / when windmilling. Having spoken to a few in-field mechanics, it's a feature that they appreciate, but pilots don't seem too bothered by. Whether it's a stripe, or a spiral, or an eccentric splodge ... doesn't really matter. What matters is that there is contrast between the base and stripe colours.

Bird Impact effect - I remember the Japanese story, but statistically, there's nothing to confirm it.

Can we change the design? - Yes, and the EngCo's do, to satisfy customers' requirements. However, ANY change to the design of the engine has to go through the same thorough, auditable, assessment...and be bought off by the relevant NAAs. It's the same paperwork trail for big changes ("Let's change the turbine blade design") and small changes ("Let's paint the spiral Orange") so there's an in-built cost for even simple changes.

Anecdote. I recall a new customer arriving for their first engine delivery of a new order - and engine type that didn't previously have a stripe / spiral. At the formal handover, the customer remarked that the engine didn't have the spiral that that had demanded in the contract. Oops. However, 48 hours later, we had designed, made and fully approved a cone with a spiral. Customer happy. (As part of the approval, I had to document costs, what type of paint, how durable it was, whether the surface finish affected ice build up, fan out-of-balance, maintenance effects, how to repair, whether the solvents affected the underlying material strength, etc etc etc. Simple change, but thoroughly investigated and documented. Isn't that the right thing to do .. or should we just slap on some random paint?)
 
stratclub
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Re: Engine spinner pattern question

Mon Jan 07, 2019 11:04 am

Great explanation. I eluded to that in my last post and your explanation is spot on. Even with small engineering changes you still have to jump through all the hoops.
 
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LoganTheBogan
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Re: Engine spinner pattern question

Thu Jan 10, 2019 8:46 am

I've seen quite a few Jetstar 787s without spinners on their GEnx engines. I'm sure there are more out there. Is there are reason for this?
Anyone who has never made a mistake has never tried anything new.
 
WPvsMW
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Re: Engine spinner pattern question

Thu Jan 10, 2019 9:22 am

Operator or lessor/buyer ordered them unpainted. Saved a few dollars. Increased ramp risk.
 
Apprentice
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Re: Engine spinner pattern question

Fri Jan 11, 2019 10:24 pm

Hello, another misconception, bird fly at low altitude.
We had a Martinair flight, Santiago de Chile to Miami , over the Andes, and when crossing mountains, it “encontered“ a CONDOR. Thanks god, it hit the a/c nose, so no engine damaged, no structural repair, just an AOG, waiting for a new Nose Cowl.

Rgds
“An4; IL18; IL6; Tu5; D10; MD11; MD83; B32; B34: B37; B744; B748; B752; B763; B772; B773; B77W; A320; A332; A333; A342; A343.
"A NO" is a positive answer., "DON'T KNOW" is not. My Tutor (a wise man)
“CUBANA” 90 years Flying”
 
riyarathi
Posts: 1
Joined: Fri Jan 18, 2019 10:57 am

Re: Engine spinner pattern question

Mon Jan 21, 2019 8:18 am

Great information. its working.very helpful discussion i found over here.Thanks for this valuable post.
Hi, I am Riya Rathi, working on  platform. I am work with best civil design firm CRBtech Solution. We can provide the best civil design online training  in Pune. The civil engineering has achieve most prominent position in the market.

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