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Embraer 135/145 Performance Question.  
User currently offlineBBJII From United Kingdom, joined Jul 2005, 850 posts, RR: 4
Posted (8 years 5 months 1 week 5 days 7 hours ago) and read 5597 times:

I always thought that there was no major difference between the 2 types.
Just the size and seating capacity of course.

So why can the 135 / Legacy Biz Jet operate at Airports where the 145 can't?

Is there a different approach speed, or speed brake issue?

Main airport i'm think of is LCY. (London City).

 wave 


Remember: The Bird Hit You, You Didn't Hit The Bird.....
20 replies: All unread, jump to last
 
User currently offlinePVD757 From United States of America, joined Aug 2003, 3406 posts, RR: 17
Reply 1, posted (8 years 5 months 1 week 5 days 7 hours ago) and read 5571 times:

Emb's website should have the performance characteristics as far as take off and landing distances. The 145 is the worst performer of the three(140 included) IIRC.

User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 2, posted (8 years 5 months 1 week 5 days 6 hours ago) and read 5536 times:

Quoting BBJII (Thread starter):
So why can the 135 / Legacy Biz Jet operate at Airports where the 145 can't?

just a thought here.... it's smaller and weighs less.....??? Thus it needs a shorter runway to take off and land on..??



"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offlineBBJII From United Kingdom, joined Jul 2005, 850 posts, RR: 4
Reply 3, posted (8 years 5 months 1 week 5 days 5 hours ago) and read 5503 times:

Quoting EMBQA (Reply 2):
it's smaller and weighs less.....??? Thus it needs a shorter runway to take off and land on

there not alot of difference in the weight...Are the engines larger/more powerful? on the 145?



Remember: The Bird Hit You, You Didn't Hit The Bird.....
User currently offlineTornado82 From , joined Dec 1969, posts, RR:
Reply 4, posted (8 years 5 months 1 week 5 days 5 hours ago) and read 5485 times:

The 135 power/weight ratio is better.

The 145XR, though weighing more than the "base" 145 @ their respective MTOW's, has better performance too.


User currently offlineBBJII From United Kingdom, joined Jul 2005, 850 posts, RR: 4
Reply 5, posted (8 years 5 months 1 week 5 days 5 hours ago) and read 5480 times:

Thanks Tornado82  Smile

 wave 



Remember: The Bird Hit You, You Didn't Hit The Bird.....
User currently offlinePPVRA From Brazil, joined Nov 2004, 8868 posts, RR: 40
Reply 6, posted (8 years 5 months 1 week 5 days 5 hours ago) and read 5471 times:

Quoting BBJII (Reply 3):
Quoting EMBQA (Reply 2):
it's smaller and weighs less.....??? Thus it needs a shorter runway to take off and land on

there not alot of difference in the weight...Are the engines larger/more powerful? on the 145?

They have the same engines as the 145.

Cheers



"If goods do not cross borders, soldiers will" - Frederic Bastiat
User currently offlineTornado82 From , joined Dec 1969, posts, RR:
Reply 7, posted (8 years 5 months 1 week 5 days 5 hours ago) and read 5463 times:

Quoting BBJII (Reply 5):
Thanks Tornado82 Smile

You're welcome sir.  Smile


User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 8, posted (8 years 5 months 1 week 5 days 5 hours ago) and read 5455 times:

Quoting BBJII (Reply 3):
there not alot of difference in the weight

Just using the ER models as a base line....

EMB-135ER zero weight is: 34,392lbs... AE3007A @7580lbs T/O Thrust
EMB-145ER zero weight is: 37,698lbs... AE3007A @7580lbs T/O Thrust

That is a 3,300lbs differeance..... nearly 20% more for the EMB-145....far from 'not a lot'. Both aircraft use the same engine w/ the same rating, so in turn its pushing a smaller, lighter aircraft with the EMB-135.

[Edited 2005-11-06 19:58:52]


"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offlineLegacy135 From Switzerland, joined May 2005, 1052 posts, RR: 27
Reply 9, posted (8 years 5 months 1 week 5 days 1 hour ago) and read 5347 times:

Not only the Legacy, also the 135 Airliner can operate at LCY. So does for example actually Luxair.

The Legacy can be considered as the "GTI" version of all, as it does have the most powerful engines, the A7001E. This engine has 3 take off modes, the others only have two. The third mode, the so called E-Take Off, boosts the aircraft with up to nearly 8'800 lbs of thrust. This is a considerably better performance - weight ratio than on all the others. As far as I know does the XR come with the same ones, but has also a higher total weight.

If we compare the airliners, you may see, that a standard 135 is about 1000 kg lighter on weight than the same version of the 145. This as well makes the 135 the much better short field aircraft. If we compare those numbers, it becomes obvious, that the 145 with a payload restriction of 37 passengers is by far not as good as a full 135, as the smaller type is with this same load significantly lighter on weight. So it becomes clear, that if there is a restriction with a runway or obstacles, the smaller type is well of advantage.

On the steep approach at LCY we do also face the weight problem. The Embraer is a kind of a glider and the crew needs to plan ahead to reduce the speed. This does also say, that it does not permit descends at any angle without regaining speeds. The smaller type, the 135 airframe, is able to perform the steep approach into LCY, the 145 airframe unfortunately does not.

If an operator wants to fly steep approaches with the 135's, they need to install a special kit, that enables them to switch the EGPWS (Enhanced Ground Proximity Warning System) in a steep approach mode. Otherwise the system would not permit this kind of operation and start to call out warnings.

Hope it helps a little, Cheers

Legacy135 Wink


User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 10, posted (8 years 5 months 1 week 5 days 1 hour ago) and read 5333 times:

EMB-135ER zero weight is: 34,392lbs... AE3007A @7580lbs T/O Thrust
EMB-145ER zero weight is: 37,698lbs... AE3007A @7580lbs T/O Thrust


..and for the Legacy....

EMB-135BJ zero weight is: 35,274lbs... AE3007AIE @ 8,895lbs T/O thrust



"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offlineKcrwFlyer From United States of America, joined May 2004, 3761 posts, RR: 8
Reply 11, posted (8 years 5 months 1 week 5 days 1 hour ago) and read 5319 times:

I always thought that each erj had a slightly different version of the engine.

User currently offlineContnlEliteCMH From United States of America, joined Mar 2005, 1450 posts, RR: 44
Reply 12, posted (8 years 5 months 1 week 5 days 1 hour ago) and read 5309 times:

Quoting EMBQA (Reply 8):
That is a 3,300lbs differeance..... nearly 20% more for the EMB-145....far from 'not a lot'.

Unless I misinterpret something you've said, the 3,300 lb difference between the two aircraft you've listed is *10%*, which is not even close to 20%. The difference is still significant, though.

This reminds me of The Shawshank Redemption. Morgan Freeman narrates to tell us that the movie's hero crawled through 500 yards of unimaginable filth. Then he says, "That's nearly half a mile." Ummmm... no. It's only slightly more than 1/4 mile. It's a long way to crawl through a raw sewage pipe, but it's not even close to 1/2 mile.



Christianity. Islam. Hinduism. Anthropogenic Global Warming. All are matters of faith!
User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 13, posted (8 years 5 months 1 week 5 days 1 hour ago) and read 5303 times:

Yup, by the time I realized my math was wrong, I could not edit it... D'ooh


"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offlineLegacy135 From Switzerland, joined May 2005, 1052 posts, RR: 27
Reply 14, posted (8 years 5 months 1 week 4 days 23 hours ago) and read 5254 times:

Quoting EMBQA (Reply 10):
EMB-135ER zero weight is: 34,392lbs... AE3007A @7580lbs T/O Thrust
EMB-145ER zero weight is: 37,698lbs... AE3007A @7580lbs T/O Thrust

..and for the Legacy....

EMB-135BJ zero weight is: 35,274lbs... AE3007AIE @ 8,895lbs T/O thrust

This is correct, thank you for looking up the numbers. Don't get fooled to much by the weights. As you probably know, those numbers are communicated by the manufacturer and very often far from reality.

About the thrust ratings of the engines: The A engine has two take off power settings, ALT-T/O1 (option to safe engines) and T/O1 (max T/O thrust). The power for T/O1 is then logically 7580lbs. The Legacy has additionally the E T/O1 rating (E for extra power). Only on the E T/O1 the engine will provide those 8'895 lbs of thrust. The A1E engine on T/O1 gives you 8'000 lbs, so not that much more than the normal "A" version.

Most of the operators are in a maintenance contract with Rolls-Royce Allison for their engines. You pay a fixed amount per hour and they provide you spare parts, log engines and condition and pay for labor. The hourly fee is in direct relation of how those engines are used. In other words, the higher ratings are strongly limited, otherwise the hourly rate will jump up extremely. Normally those contracts say something like 80% ALT T/O1 take offs.

So you see, even having lots of power available, you still may only use it under exceptional conditions.

Cheers
Legacy135 Wink


User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 15, posted (8 years 5 months 1 week 4 days 23 hours ago) and read 5245 times:

Quoting Legacy135 (Reply 14):
Don't get fooled to much by the weights. As you probably know, those numbers are communicated by the manufacturer and very often far from reality.

I'll find out how close they are. We weighted a Legacy at work on Thursday.....

[Edited 2005-11-07 01:58:50]


"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offlineMarkus From United States of America, joined May 1999, 275 posts, RR: 0
Reply 16, posted (8 years 5 months 1 week 4 days 20 hours ago) and read 5186 times:

What flap setting does the -135 use to get out of LCY. Do they use the standard 9deg or 18 or 22 for more lift?
Cheers


User currently offlineBBJII From United Kingdom, joined Jul 2005, 850 posts, RR: 4
Reply 17, posted (8 years 5 months 1 week 4 days 11 hours ago) and read 5111 times:

Legacy 135....Thanks

Welcome to my RU list

 wave 



Remember: The Bird Hit You, You Didn't Hit The Bird.....
User currently offlineChqdispatch From United States of America, joined Sep 2004, 50 posts, RR: 0
Reply 18, posted (8 years 5 months 1 week 4 days 10 hours ago) and read 5037 times:

I love working with the 135's. Full flight (37 pax), ETE is close to two hours and I can still give them a good alternate if they need one with some extra gas to boot.

User currently offlineLegacy135 From Switzerland, joined May 2005, 1052 posts, RR: 27
Reply 19, posted (8 years 5 months 1 week 4 days 9 hours ago) and read 5009 times:

Quoting Markus (Reply 16):
Do they use the standard 9deg or 18 or 22 for more lift?

Actually Flaps 22 is for landing only, as Flaps 45. Flaps 22 is also the requirement to fly CAT II approaches, Embraer did not certify the aircraft for CAT II/Flaps 45

The Legacy on the other hand does not have the Flaps 18 position. There is actually a mechanic prevention on the flaps lever that inhibits the Flap 18 setting. The 135's and the 145's can absolutely be flown as a Flaps 18 Take Off. As I understand from other operators, it is more common to go Flaps 9 anyhow.

For the LCY case I can only give you my assumption, as I do fly the Legacy and we don't have the flaps 18 at all on it:
As LCY has rather high obstacles (Carnery Wharf etc) I guess they still go with flaps 9 as this simply leads to a better second segment climb gradient, in case of an engine failure. Flaps 18 for sure has it's advantages in regard to runway length required but will not lead to the best possible climb. LCY in the meantime has somewhat as 1'500 meters of runway, is at sea level and suffers from moderately cool British weather, so I guess the runway isn't that much the problem there.

Cheers
Legacy135  Wink


User currently offlineMarkus From United States of America, joined May 1999, 275 posts, RR: 0
Reply 20, posted (8 years 5 months 1 week 3 days 9 hours ago) and read 4834 times:

Thanks for the info. The only reason I mentioned flaps 18 is when I was working for COEX flaps 18 was not available on the -135s or -145s. I left before the -145XRs showed up on property...but I'd assume they're inop on the XRs as well. I've seen pictures of -145s taking off from some rather short runways. From the pics it was obvious that flaps were down further than 9 degrees.
Cheers,
Markus


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