ERJ-145....
- Thread starter Cherokee_Cruiser
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IrishSheepdog
Sitting in the median
Not sure if it's a problem on the CRJ/ERJ, but on some aircraft (CE-750 being one of them) idle thrust is so great that it creates an excessive taxi speed. Taxiing with one thrust reverser open reduces the taxi speed to a more managable one.
Reversers in the 1900 worked pretty good, but hardly more than "Beta".
Beta rocks. You can darned near steer the aircraft to the gate using differential beta alone. Plus it makes that cool sound... "EEEeeeeeeoooOoOWWWWWWWWW.....GGEEEEEEEEEooooooooOOOOWWWWWWMMMMMBBBHHH"
Beta rocks. You can darned near steer the aircraft to the gate using differential beta alone. Plus it makes that cool sound... "EEEeeeeeeoooOoOWWWWWWWWW.....GGEEEEEEEEEooooooooOOOOWWWWWWMMMMMBBBHHH"
FL270
New Member
Yeah, you've got to love beta. I hardly ever touch the brakes in the King Air ... really only use them to stop the airplane completely. I taxi using beta to control speed (and differential beta around corners), and after landing use beta to slow to taxi speed (maybe reverse if the runway is short, I want an early turnoff, contaminated rwy, etc.) and taxi to parking. A tap on the brakes will stop the airplane nicely once I reach the parking spot, but very little use of brakes otherwise.
Now jets are a whole different story. Lots of braking there because reversers make a lot of noise but don't do an enormous amount to help stop the airplane.
FL270
Now jets are a whole different story. Lots of braking there because reversers make a lot of noise but don't do an enormous amount to help stop the airplane.
FL270
Maximilian_Jenius
Super User
Okay....and what is "Beta" for us pilots on here who don't fly turboprops?
Matthew
Matthew
sorrygottarunway
Well-Known Member
the engines in these jetst do not reverse direction correct?
my concept of reverse thrust was that the buckets, shaft, opens or moves rearward (or on the airbus the flappy things open) directing thrust away from the rearward direction, causing more drag against the airplane. Then speeding up the engines could cause more of this effect...
I only fly pipers and the occasional 172, so I have no experience with reverse except in my car, which was one day TOO effective as I reversed back into my garage wall when thinking it was in drive.
my concept of reverse thrust was that the buckets, shaft, opens or moves rearward (or on the airbus the flappy things open) directing thrust away from the rearward direction, causing more drag against the airplane. Then speeding up the engines could cause more of this effect...
I only fly pipers and the occasional 172, so I have no experience with reverse except in my car, which was one day TOO effective as I reversed back into my garage wall when thinking it was in drive.
FL270
New Member
No, then engines do not change their direction of rotation at all, at any time.
In a turboprop such as the one I fly, going to reverse means reducing the pitch of the propeller blades through flat pitch so that they generate thrust opposite the direction of travel of the airplane. It's a controllable pitch prop, similar to what you would see on a 172RG or an Arrow, we just have a much wider pitch envelope to work with.
In jets, forward engine thrust is being deflected. Jet thrust reversers (TRs) can be divided in to two categories ... pre-exit and post-exit. Post-exit reversers, such as those found on airplanes like the MD-80, DC-9, Beechjet 400A, etc., are basically "clamshell doors" which open behind the engine and deflect the exhaust forward to help slow the airplane. Pre-exit reversers change the direction of the air before it leaves the exhaust. In most high-bypass-turbofan engines, only the air in the fan section is reversed. This is what occurs on CFM-powered 737s (the -300 and later series). A "translating sleeve", as it is called, slides backwards on the engine cowl. This causes a panel to deflect the front-to-back air flow through the fan section forward, where it is exhausted through that grid you see from your seat when the sleeve opens. On the Airbus it is similar (many Airbus 320 family aircraft are powered by the same CFM56 engines as on the 737), except that rather than a translating sleeve, there are those series of doors that open to direct engine thrust opposite the direction of travel.
I hope this makes more sense now.
FL270
In a turboprop such as the one I fly, going to reverse means reducing the pitch of the propeller blades through flat pitch so that they generate thrust opposite the direction of travel of the airplane. It's a controllable pitch prop, similar to what you would see on a 172RG or an Arrow, we just have a much wider pitch envelope to work with.
In jets, forward engine thrust is being deflected. Jet thrust reversers (TRs) can be divided in to two categories ... pre-exit and post-exit. Post-exit reversers, such as those found on airplanes like the MD-80, DC-9, Beechjet 400A, etc., are basically "clamshell doors" which open behind the engine and deflect the exhaust forward to help slow the airplane. Pre-exit reversers change the direction of the air before it leaves the exhaust. In most high-bypass-turbofan engines, only the air in the fan section is reversed. This is what occurs on CFM-powered 737s (the -300 and later series). A "translating sleeve", as it is called, slides backwards on the engine cowl. This causes a panel to deflect the front-to-back air flow through the fan section forward, where it is exhausted through that grid you see from your seat when the sleeve opens. On the Airbus it is similar (many Airbus 320 family aircraft are powered by the same CFM56 engines as on the 737), except that rather than a translating sleeve, there are those series of doors that open to direct engine thrust opposite the direction of travel.
I hope this makes more sense now.
FL270
Kingairer
'Tiger Team' Member
[ QUOTE ]
I see quiet a few number of ERJ's here at SJC and i rarely see one that would NOT use their reverse thrusters. I have also seen them use their reverse thrusters while taxing the reason-from what i was told, is that you save wear and tare on the brakes.
[/ QUOTE ]
see and hear reverse thrust are two differnt things. You may just see the buckets being deployed, but again its techniques and company policies. Also, at mine and most ERJ companies, rev thrust for taxi or power backs is not an option.
I see quiet a few number of ERJ's here at SJC and i rarely see one that would NOT use their reverse thrusters. I have also seen them use their reverse thrusters while taxing the reason-from what i was told, is that you save wear and tare on the brakes.
[/ QUOTE ]
see and hear reverse thrust are two differnt things. You may just see the buckets being deployed, but again its techniques and company policies. Also, at mine and most ERJ companies, rev thrust for taxi or power backs is not an option.
IrishSheepdog
Sitting in the median
I wish I could make a Saab 340 flight bag sticker with that on it!
DakotaBlue
New Member
hey chicaga...do you guys have competitions to see who can get more stickers on their chart case or is it personal preference....ya know kinda like "the kid with the most toys is the coolest"?
IrishSheepdog
Sitting in the median
Nah, it's in our GOM that we have to have a minimal amount of "stickers", so most of us try to keep it pretty tame. I call them our "pieces of flair."
I have a Saab sticker, ALPA 9/11 ribbon sticker, U of I Alumni sticker, JetCareers Vegas Crawl sticker (yeah!), and an ATA unaccompanied minor sticker on my bag (it says "ATA takes care of me!")
I have a Saab sticker, ALPA 9/11 ribbon sticker, U of I Alumni sticker, JetCareers Vegas Crawl sticker (yeah!), and an ATA unaccompanied minor sticker on my bag (it says "ATA takes care of me!")
Maximilian_Jenius
Super User
So what about the thrust reversers on the MD-90's there not a clam shell design like the MD-80 series. On the International Aero engine it looks like the back end of the engine splits in half down the middle.
What kinda TR are they?
Matthew
What kinda TR are they?
Matthew
N9103M
Well-Known Member
Most high-bypass turbofan engines (Like the IAE enignes on the MD-90) have "Translating Cowl" reversers. When reverse thrust is selected, the aft part of the cowling slides back exposing grates for reverse thrust to exit. Internally, blocker doors (visible on the outside on the CFM powered Airbuses) block the high bypass air and direct it out the grates. Thereby creating reverse thrust....
mtsu_av8er
Well-Known Member
[ QUOTE ]
In TUS I lived 5 miles from the airport and you could hear the noise from airliners doing reverse thrust that far away more especially in the morning when all the cargo planes come in to sit all day.
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Marine Corps Boot Camp, San Diego...we were located right beside the runway at KSAN. All day and all night, that's all you heard. I never really had time to spot or marvel at all of the airplanes, but when you're a 45 minute flight away from home, it's enough to drive you crazy!!!
In TUS I lived 5 miles from the airport and you could hear the noise from airliners doing reverse thrust that far away more especially in the morning when all the cargo planes come in to sit all day.
[/ QUOTE ]
Marine Corps Boot Camp, San Diego...we were located right beside the runway at KSAN. All day and all night, that's all you heard. I never really had time to spot or marvel at all of the airplanes, but when you're a 45 minute flight away from home, it's enough to drive you crazy!!!
