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LimaFoxTango
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Joined: Wed Jun 16, 2004 11:33 pm

Why Not Redesign Old Aircraft?

Fri Jul 16, 2004 2:46 am

Hello fellow a-netters. First time posting a question here. Anyway, here it goes.

I have always wondered, aircrafts such as DC-10's, MD-11's, 727, Twin Otters and many others have been some of the greatest aircrafts ever built. In the case of the Twin Otter for example, i doubt theres any other aircraft that can beat its STOL capabilities. Why is it that DeHavilland/Bombardier, havent decided to remodel the Otter with better engines, advanced cockpit technology and even FBW technology. This way, manufacturers can save millions of dollars to design a whole new aircraft.

The point I'm trying to make is that I'm quite sure that every imaginable type of aircraft have been designed. Instead of building ugly futuristic looking aircraft, simply redesign old aircraft that have proved itself.

Sure would like to hear what other people have to say about this.
You are said to be a good pilot when your take-off's equal your landings.
 
LimaFoxTango
Topic Author
Posts: 1008
Joined: Wed Jun 16, 2004 11:33 pm

RE: Why Not Redesign Old Aircraft?

Fri Jul 16, 2004 2:56 am

Oops. I accidentally posted this question in the Civil Aviation forum. Could the moderators please move this to the Tech Ops forum?

Thanks...
You are said to be a good pilot when your take-off's equal your landings.
 
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northstardc4m
Posts: 3451
Joined: Fri Apr 28, 2000 11:23 am

RE: Why Not Redesign Old Aircraft?

Fri Jul 16, 2004 2:56 am

Well...

In the case of the Twotter it wasnt Bombardier who killed it, it was the previous owners of DHC, Boeing, who decided to concentrate on the Dash 8 instead.

Saving Millions is a bit misleading BTW. The changes you talk about making would require major design changes, therefore major tool rebuilding and probably recertification costs as well.

Now on top of this you have the aerodynamics issue:

Older planes were designed without the aid of modern computers or recent knowledge. Their wings for example are less efficient than more modern ones. Features like Supercritical wings, winglets or fences, etc which are now extremly common.

So, some planes have been modernised with good results (737, 747) and some with poorer results (DC-10>MD-11). The thing too is that short of specialised aircraft, the market will almost always pick up competing designs than will be "better" than the updated designs so there will be a back and forth war in many areas (just look at 727/737 vs DC9/MD80 vs A32x sales over the years) that new designs have definite advantages in.
Those who would give up Essential Liberty to purchase a little Temporary Safety, deserve neither Liberty nor Safety.
 
AmericanAirFan
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RE: Why Not Redesign Old Aircraft?

Fri Jul 16, 2004 3:03 am

Here are some good reasons why they don't upgrade all those fantastic planes
1.Money
2.Eficency
3.Size

Very good topic though I wish that they could keep some of the old classic airliners and upgrade them.

-American Air Fan

hope that Helps
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OD720
Posts: 1856
Joined: Sun Feb 16, 2003 6:46 am

RE: Why Not Redesign Old Aircraft?

Fri Jul 16, 2004 3:09 am

Things evolve and new ideas come up. The types you mention already have their place in aviation history.
 
BUFjets
Posts: 222
Joined: Wed Jan 10, 2001 9:27 pm

RE: Why Not Redesign Old Aircraft?

Fri Jul 16, 2004 4:03 am

Boeing offers just what you are asking for the DC-10. It's called the MD-10. Fed Ex is or was having the upgrade done on some freighters.
 
lowrider
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RE: Why Not Redesign Old Aircraft?

Fri Jul 16, 2004 4:06 am

"...and many others have been some of the greatest aircrafts ever built."

The greatest aircraft ever built has yet to be built. All we have is the greatest aircraft so far. To assume that no further improvement is possible demonstrates a type of thinking that will insure that no further improvement is made. I worry that not enough emphasis is placed on new and innovative designs, technology, and methods.
Proud OOTSK member
 
citationjet
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Joined: Sun Mar 09, 2003 2:26 am

RE: Why Not Redesign Old Aircraft?

Fri Jul 16, 2004 5:12 am

Another aspect is the certification of an updated existing design. With the FAA's Changed Product Rule (CPR), "Significant" changes to an aircraft require it to meet the latest regulations. The CPR motto is "Enhancing safety by applying the latest airworthiness standards".
This is only part of the reason, and not the entire reason for not redesigning older aircraft. But it does enter into the cost equation (money) as described by AmericanAirFan in reply #3.
Basically, for a significant change to a product you must START with the LATEST amendment of the regulations, and then justify why you do not meet that for every regulation. This is called the "top down approach" to developing the certification basis.
Basically, old design would have difficulty in meeting items such as dynamic seats, system safety, interior structures, flammability, HIRF & Lightning, environmental systems, etc.
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