Why four engines?

MarineNav · August 17th, 2004, 22:46

Hello All,

Does anyone know why the BAE-146 was designed with 4 engines? It seems overkill to me. And I would imagine that fuel & maintenance requirements must be more than for any other similarly sized "regional" aircraft.

Air Wisconsin

Thanks,

JR

gurisudenko · August 17th, 2004, 22:50

BECAUSE IT LOOKS COOL DAMNIT! It tricks the eye into thinking you're not commuting, you're RIDING A SPACE SHIP.

[img]/ubbthreads/images/graemlins/spin2.gif[/img]

If I remember correctly, those little turbofans aren't too powerful...I honestly don't know why they didn't just use two that were more powerful.

One of my favorite planes. Ahhh....Have you seen the Dornier 328 jet that Delta's Connection Carriers fly? [img]/ubbthreads/images/graemlins/buck.gif[/img]

TrinidadGT20 · August 17th, 2004, 22:58

I asked that exact same question in January on a.net and a moderator removed my post because it was too "general". $5 a month to get ridiculed by their mods... yeah whatever! Needless to say, I'm not an a.net member anymore. I still don't know the answer to this question.

MikeD · August 17th, 2004, 23:02

[ QUOTE ]
I asked that exact same question in January on a.net and a moderator removed my post because it was too "general". $5 a month to get ridiculed by their mods... yeah whatever! Needless to say, I'm not an a.net member anymore. I still don't know the answer to this question.

[/ QUOTE ]

Your post here is being removed at this very moment....... [img]/ubbthreads/images/graemlins/grin.gif[/img]

Citationkid · August 17th, 2004, 23:05

Maybe to keep it quite (isn't that one of the things they advertise?), or because there isn't enough clearnece if you hang two big engine under the wings. Maybe they'd have to design new engines to only have two, but if they went with four they could use an existing engine.

C650CPT · August 17th, 2004, 23:10

Perhaps the originall customer requested 4 engines. Not sure if this is the case or not, but I would think that the launch / target customers on airplanes would have a lot of say in the design / layout.

Jim

gurisudenko · August 17th, 2004, 23:17

SPACE

SHIP

That's the only reason. [img]/ubbthreads/images/graemlins/bandit.gif[/img]

TrinidadGT20 · August 17th, 2004, 23:18

MikeD,

You forgot to ridicule me [img]/ubbthreads/images/graemlins/grin.gif[/img]

MikeD · August 17th, 2004, 23:20

[ QUOTE ]
SPACE

SHIP

That's the only reason. [img]/ubbthreads/images/graemlins/bandit.gif[/img]

[/ QUOTE ]

BAe-146 and Space Shuttles.......

I still don't see the connection. [img]/ubbthreads/images/graemlins/confused.gif[/img]

Damn late work nights.

L1011.......you're right I forgot to ridicule you! What lousy customer service on my part. [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/smile.gif[/img]

.....give me a minute to figure out some uppity-a.net comments......

UAL747400 · August 17th, 2004, 23:31

[ QUOTE ]
SPACE

SHIP

That's the only reason.

--------------------------------------------------------------------------------

BAe-146 and Space Shuttles.......

I still don't see the connection.

[/ QUOTE ]

Me either. I think I looks more like some kind of insect. It looks the best when it flys toward you, turns, then flies away from you.

Tom

FalconCapt · August 17th, 2004, 23:35

[ QUOTE ]
Hello All,

Does anyone know why the BAE-146 was designed with 4 engines? It seems overkill to me. And I would imagine that fuel & maintenance requirements must be more than for any other similarly sized "regional" aircraft.

[/ QUOTE ]

Most likely to fulfil some short field, steep climb gradient requirement for particular operations. Remember the FAA considers Second Segment Turbo-Jet Climb performance with One Engine Inoperative... In a 2 engine airplane, you loose 50% of your thrust, in a 3 engine airplane you loose 33% of your thrust, in a 4 engine airplane, you have only lost 25% of your thrust...

On all Turbo-Jet departures, you calculate your climb gradient based on One Engine Inoperative (OEI), a 4 engine airplane does MUCH better with 3 running than a 2 engine airplane does on one...

Doug Taylor · August 17th, 2004, 23:35

Hey, I'll ridicule you for free! See, JC is such a bargain!

I think it was something to do with making an extraordinarily low noise profile aircraft for ultra noise sensitive areas in Europe.

Four small engines may less racket than two larger ones. But I may be wrong.

pilot602 · August 17th, 2004, 23:36

'Cuz it's British? [img]/ubbthreads/images/graemlins/grin.gif[/img]

viper548 · August 17th, 2004, 23:37

I think it MIGHT have something to do with performance at certain airports such as Aspen. They are required to calculate perfomance with one engine inop. 3/4 engines is better than 1/2.

Alchemy · August 17th, 2004, 23:54

I remember reading somewhere that it's the only RJ capable of taking off from aspen on the hottest days of summer. Short Field TO performance would be my guess.

Noise abatement was a big player as well, if I recall.

FalconCapt · August 18th, 2004, 00:06

[ QUOTE ]
I remember reading somewhere that it's the only RJ capable of taking off from aspen on the hottest days of summer. Short Field TO performance would be my guess.

[/ QUOTE ]

This is due to climb performance, not runway performance...

MarineNav · August 18th, 2004, 00:27

Thank you everyone for your replies. Now this makes me think if it would be feasible to reengine them with only 2 modern turbofans. And that leads to wonder why they don't reengine the B-52's with 4 modern turbofans.

Thanks again,

JR

UAL747400 · August 18th, 2004, 00:42

I think I read somewhere else that they are going to later down the road. Could be wrong though.

Tom

Bog · August 18th, 2004, 02:49

It has 4 because there isn't enough room for 6! Ha!

Get stuck behind one and you'll agree. [img]/ubbthreads/images/graemlins/banghead.gif[/img]

flyover · August 18th, 2004, 08:04

[ QUOTE ]
Most likely to fulfil some short field, steep climb gradient requirement for particular operations. Remember the FAA considers Second Segment Turbo-Jet Climb performance with One Engine Inoperative... In a 2 engine airplane, you loose 50% of your thrust, in a 3 engine airplane you loose 33% of your thrust, in a 4 engine airplane, you have only lost 25% of your thrust...

On all Turbo-Jet departures, you calculate your climb gradient based on One Engine Inoperative (OEI), a 4 engine airplane does MUCH better with 3 running than a 2 engine airplane does on one...

[/ QUOTE ]

Ding-ding-ding. That is exactly right. This airplane was initially marketed as a STOL jet. It's target market was to serve smaller airports in Europe. Aspen Airways bought them to use on high altititide short runway operations they had been flying with Dash-7s. It was a very specialized jet that just kept selling.

Minnesota_Flyer · August 18th, 2004, 11:26

So is the Avro RJ 85 (I have been unsuccessful in linking a picture) just a blatant copy?

I love these guys. I can always tell when it is one of the Avros coming over my house (I'm on the approach path for MSP) because they usually drop flaps over my house and the flaps just SCREAM as they come down.

I'm easily amused. [img]/ubbthreads/images/graemlins/grin.gif[/img]

MF

Doug Taylor · August 18th, 2004, 11:39

As far as I know, an Avrojet is nothing more than a remarketed BAe-146.

flyover · August 18th, 2004, 12:25

[ QUOTE ]
So is the Avro RJ 85 (I have been unsuccessful in linking a picture) just a blatant copy?

[/ QUOTE ]

In the same sense the MD-80 is a "blatant copy" of the DC-9. It's an updated, redesignated airplane.

The BAe 146 first flew commercially in 1983. The aircraft was designed specifically to meet the demanding requirements of the regional air transport market where heavy utilisation over short sector lengths coupled with high reliability are paramount requirements. Outstanding airfield performance and whisper-jet noise levels are other attributes of the aircraft, which offers excellent profit potential on low-density routes.

A total of 221 BAe 146s were built and 219 were delivered between 1983 and 1993 when it was succeeded by the Avro RJ Series.

Three different length versions of the BAe 146 were built - the Series 100 with 70-84 seats, the 200 Series with 85-100 seats and the 300 Series with 100-112 seats. The aircraft was also manufactured as a pure freighter (QT- Quiet Trader), a QC- Quick Change variant and as a VIP transport aircraft (the Statesman) (see BAE Systems for more information)

Doug Taylor · August 18th, 2004, 14:59

Reminds me of when someone asked "Why does the DC-10 have three engines?"

"Because it needs 'em!"

August 17th, 2004, 22:46	#1
MarineNav Senior Member Join Date: Apr 2003 Location: Santa Clara, CA Posts: 301	Why four engines? Hello All, Does anyone know why the BAE-146 was designed with 4 engines? It seems overkill to me. And I would imagine that fuel & maintenance requirements must be more than for any other similarly sized "regional" aircraft. Air Wisconsin Thanks, JR

August 17th, 2004, 22:50	#2
gurisudenko Junior Member Join Date: Aug 2004 Location: Saint Cloud, MN USA Posts: 260	Re: Why four engines? BECAUSE IT LOOKS COOL DAMNIT! It tricks the eye into thinking you're not commuting, you're RIDING A SPACE SHIP. [img]/ubbthreads/images/graemlins/spin2.gif[/img] If I remember correctly, those little turbofans aren't too powerful...I honestly don't know why they didn't just use two that were more powerful. One of my favorite planes. Ahhh....Have you seen the Dornier 328 jet that Delta's Connection Carriers fly? [img]/ubbthreads/images/graemlins/buck.gif[/img]

August 17th, 2004, 22:58	#3
TrinidadGT20 Senior Member Join Date: Feb 2001 Location: Red Sox Nation Posts: 1,470	Re: Why four engines? I asked that exact same question in January on a.net and a moderator removed my post because it was too "general". $5 a month to get ridiculed by their mods... yeah whatever! Needless to say, I'm not an a.net member anymore. I still don't know the answer to this question.

August 17th, 2004, 23:02	#4
MikeD Administrator Join Date: Feb 2003 Location: Pinal Airpark Posts: 6,897	Re: Why four engines? [ QUOTE ] I asked that exact same question in January on a.net and a moderator removed my post because it was too "general". $5 a month to get ridiculed by their mods... yeah whatever! Needless to say, I'm not an a.net member anymore. I still don't know the answer to this question. [/ QUOTE ] Your post here is being removed at this very moment....... [img]/ubbthreads/images/graemlins/grin.gif[/img]

August 17th, 2004, 23:05	#5
Citationkid Senior Member Join Date: Aug 2003 Location: Delaware Posts: 1,310 Blog Entries: 5	Re: Why four engines? Maybe to keep it quite (isn't that one of the things they advertise?), or because there isn't enough clearnece if you hang two big engine under the wings. Maybe they'd have to design new engines to only have two, but if they went with four they could use an existing engine.

August 17th, 2004, 23:10	#6
C650CPT Senior Member Join Date: May 2003 Location: Home Sweet Home! Posts: 957	Re: Why four engines? Perhaps the originall customer requested 4 engines. Not sure if this is the case or not, but I would think that the launch / target customers on airplanes would have a lot of say in the design / layout. Jim

August 17th, 2004, 23:17	#7
gurisudenko Junior Member Join Date: Aug 2004 Location: Saint Cloud, MN USA Posts: 260	Re: Why four engines? SPACE SHIP That's the only reason. [img]/ubbthreads/images/graemlins/bandit.gif[/img]

August 17th, 2004, 23:18	#8
TrinidadGT20 Senior Member Join Date: Feb 2001 Location: Red Sox Nation Posts: 1,470	Re: Why four engines? MikeD, You forgot to ridicule me [img]/ubbthreads/images/graemlins/grin.gif[/img]

August 17th, 2004, 23:20	#9
MikeD Administrator Join Date: Feb 2003 Location: Pinal Airpark Posts: 6,897	Re: Why four engines? [ QUOTE ] SPACE SHIP That's the only reason. [img]/ubbthreads/images/graemlins/bandit.gif[/img] [/ QUOTE ] BAe-146 and Space Shuttles....... I still don't see the connection. [img]/ubbthreads/images/graemlins/confused.gif[/img] Damn late work nights. L1011.......you're right I forgot to ridicule you! What lousy customer service on my part. [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/smile.gif[/img] .....give me a minute to figure out some uppity-a.net comments......

August 17th, 2004, 23:31	#10
UAL747400 Old Skool Join Date: Sep 2002 Location: Grand Forks, ND (UND)/ Davenport, IA Posts: 2,204	Re: Why four engines? [ QUOTE ] SPACE SHIP That's the only reason. -------------------------------------------------------------------------------- BAe-146 and Space Shuttles....... I still don't see the connection. [/ QUOTE ] Me either. I think I looks more like some kind of insect. It looks the best when it flys toward you, turns, then flies away from you. Tom

August 17th, 2004, 23:35	#11
FalconCapt Banned Join Date: Nov 2003 Location: USA Posts: 489	Re: Why four engines? [ QUOTE ] Hello All, Does anyone know why the BAE-146 was designed with 4 engines? It seems overkill to me. And I would imagine that fuel & maintenance requirements must be more than for any other similarly sized "regional" aircraft. [/ QUOTE ] Most likely to fulfil some short field, steep climb gradient requirement for particular operations. Remember the FAA considers Second Segment Turbo-Jet Climb performance with One Engine Inoperative... In a 2 engine airplane, you loose 50% of your thrust, in a 3 engine airplane you loose 33% of your thrust, in a 4 engine airplane, you have only lost 25% of your thrust... On all Turbo-Jet departures, you calculate your climb gradient based on One Engine Inoperative (OEI), a 4 engine airplane does MUCH better with 3 running than a 2 engine airplane does on one...

August 17th, 2004, 23:35	#12
Doug Taylor Agent Smith Join Date: Dec 1969 Location: KSDL Posts: 39,749 Blog Entries: 1	Re: Why four engines? Hey, I'll ridicule you for free! See, JC is such a bargain! I think it was something to do with making an extraordinarily low noise profile aircraft for ultra noise sensitive areas in Europe. Four small engines may less racket than two larger ones. But I may be wrong.

August 17th, 2004, 23:36	#13
pilot602 Old Skool Join Date: Oct 2001 Location: who haa Posts: 3,750	Re: Why four engines? 'Cuz it's British? [img]/ubbthreads/images/graemlins/grin.gif[/img]

August 17th, 2004, 23:37	#14
viper548 Senior Member Join Date: May 2003 Location: Colorado Springs Posts: 813	Re: Why four engines? I think it MIGHT have something to do with performance at certain airports such as Aspen. They are required to calculate perfomance with one engine inop. 3/4 engines is better than 1/2.

August 17th, 2004, 23:54	#15
Alchemy Old Skool Join Date: Aug 2001 Location: Austin, TX, USA Posts: 1,721	Re: Why four engines? I remember reading somewhere that it's the only RJ capable of taking off from aspen on the hottest days of summer. Short Field TO performance would be my guess. Noise abatement was a big player as well, if I recall.

August 18th, 2004, 00:06	#16
FalconCapt Banned Join Date: Nov 2003 Location: USA Posts: 489	Re: Why four engines? [ QUOTE ] I remember reading somewhere that it's the only RJ capable of taking off from aspen on the hottest days of summer. Short Field TO performance would be my guess. [/ QUOTE ] This is due to climb performance, not runway performance...

August 18th, 2004, 00:27	#17
MarineNav Senior Member Join Date: Apr 2003 Location: Santa Clara, CA Posts: 301	Re: Why four engines? Thank you everyone for your replies. Now this makes me think if it would be feasible to reengine them with only 2 modern turbofans. And that leads to wonder why they don't reengine the B-52's with 4 modern turbofans. Thanks again, JR

August 18th, 2004, 00:42	#18
UAL747400 Old Skool Join Date: Sep 2002 Location: Grand Forks, ND (UND)/ Davenport, IA Posts: 2,204	Re: Why four engines? I think I read somewhere else that they are going to later down the road. Could be wrong though. Tom

August 18th, 2004, 02:49	#19
Bog Senior Member Join Date: Oct 2003 Location: Gilbert, AZ Posts: 1,152	Re: Why four engines? It has 4 because there isn't enough room for 6! Ha! Get stuck behind one and you'll agree. [img]/ubbthreads/images/graemlins/banghead.gif[/img]

August 18th, 2004, 08:04	#20
flyover Old Skool Join Date: Mar 2004 Location: Georgia Posts: 3,389	Re: Why four engines? [ QUOTE ] Most likely to fulfil some short field, steep climb gradient requirement for particular operations. Remember the FAA considers Second Segment Turbo-Jet Climb performance with One Engine Inoperative... In a 2 engine airplane, you loose 50% of your thrust, in a 3 engine airplane you loose 33% of your thrust, in a 4 engine airplane, you have only lost 25% of your thrust... On all Turbo-Jet departures, you calculate your climb gradient based on One Engine Inoperative (OEI), a 4 engine airplane does MUCH better with 3 running than a 2 engine airplane does on one... [/ QUOTE ] Ding-ding-ding. That is exactly right. This airplane was initially marketed as a STOL jet. It's target market was to serve smaller airports in Europe. Aspen Airways bought them to use on high altititide short runway operations they had been flying with Dash-7s. It was a very specialized jet that just kept selling.

August 18th, 2004, 11:26	#21
Minnesota_Flyer Old Skool Join Date: Mar 2004 Location: the Twin Cities of Minneapolis and St. Paul Posts: 1,895	Re: Why four engines? So is the Avro RJ 85 (I have been unsuccessful in linking a picture) just a blatant copy? I love these guys. I can always tell when it is one of the Avros coming over my house (I'm on the approach path for MSP) because they usually drop flaps over my house and the flaps just SCREAM as they come down. I'm easily amused. [img]/ubbthreads/images/graemlins/grin.gif[/img] MF

August 18th, 2004, 11:39	#22
Doug Taylor Agent Smith Join Date: Dec 1969 Location: KSDL Posts: 39,749 Blog Entries: 1	Re: Why four engines? As far as I know, an Avrojet is nothing more than a remarketed BAe-146.

August 18th, 2004, 12:25	#23
flyover Old Skool Join Date: Mar 2004 Location: Georgia Posts: 3,389	Re: Why four engines? [ QUOTE ] So is the Avro RJ 85 (I have been unsuccessful in linking a picture) just a blatant copy? [/ QUOTE ] In the same sense the MD-80 is a "blatant copy" of the DC-9. It's an updated, redesignated airplane. The BAe 146 first flew commercially in 1983. The aircraft was designed specifically to meet the demanding requirements of the regional air transport market where heavy utilisation over short sector lengths coupled with high reliability are paramount requirements. Outstanding airfield performance and whisper-jet noise levels are other attributes of the aircraft, which offers excellent profit potential on low-density routes. A total of 221 BAe 146s were built and 219 were delivered between 1983 and 1993 when it was succeeded by the Avro RJ Series. Three different length versions of the BAe 146 were built - the Series 100 with 70-84 seats, the 200 Series with 85-100 seats and the 300 Series with 100-112 seats. The aircraft was also manufactured as a pure freighter (QT- Quiet Trader), a QC- Quick Change variant and as a VIP transport aircraft (the Statesman) (see BAE Systems for more information)

August 18th, 2004, 14:59	#24
Doug Taylor Agent Smith Join Date: Dec 1969 Location: KSDL Posts: 39,749 Blog Entries: 1	Re: Why four engines? Reminds me of when someone asked "Why does the DC-10 have three engines?" "Because it needs 'em!"

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