EMBQA From United States of America, joined Oct 2003, 9286 posts, RR: 13 Reply 8, posted (7 years 6 months 2 weeks 1 day 17 hours ago) and read 4121 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"
Legacy135 From Switzerland, joined May 2005, 1052 posts, RR: 29 Reply 9, posted (7 years 6 months 2 weeks 1 day 13 hours ago) and read 4013 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.
ContnlEliteCMH From United States of America, joined Mar 2005, 1436 posts, RR: 50 Reply 12, posted (7 years 6 months 2 weeks 1 day 13 hours ago) and read 3975 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!
Legacy135 From Switzerland, joined May 2005, 1052 posts, RR: 29 Reply 14, posted (7 years 6 months 2 weeks 1 day 11 hours ago) and read 3920 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.
Legacy135 From Switzerland, joined May 2005, 1052 posts, RR: 29 Reply 19, posted (7 years 6 months 2 weeks 21 hours ago) and read 3675 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.
Markus From United States of America, joined May 1999, 275 posts, RR: 0 Reply 20, posted (7 years 6 months 1 week 6 days 21 hours ago) and read 3500 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.