Aguilo From United States of America, joined Apr 2004, 243 posts, RR: 0 Posted (10 years 3 months 4 weeks 1 hour ago) and read 3115 times:
Many of USAirs 733 and all 727s don't have engines with cowlings that open once reverse thrust is applied. So how does this work? With no openings in the cowl where does the reversed thrust go if the engine is still sucking in air through the fan?
Aguilo From United States of America, joined Apr 2004, 243 posts, RR: 0
Reply 2, posted (10 years 3 months 4 weeks 1 hour ago) and read 3047 times:
futureualpilot: I know its not always necessary to use reverse, but I think its pretty obvious that they are in fact using reverse thrust when you can feel and hear the reverse thrust, but are sitting right next to the engine (on a 733) and not seeing the cowling open up.
Seems that the opening cowls are found on newer engines primarily (DC9 MD80 excluded)
So the question remains: Where does the thrust go?
BA From United States of America, joined May 2000, 11153 posts, RR: 59
Reply 4, posted (10 years 3 months 4 weeks ago) and read 2955 times:
Reverse thrust is simply not possible without cowl movement.
There are different types of cowel movements, you have the sliding cowls which is most common such as those on the CFM56s on the 737s, you have the petal cowels such as those on the CFM56ss on the A340-300s and A320 family, and you have the clamshell reversers such as those on the JT8Ds on the DC-9 and MD-80 series.
The 717's BR715 has a unique looking petal reverser which misleads people to think it is a clamshell reverser when it is not.
"Generosity is giving more than you can, and pride is taking less than you need." - Khalil Gibran
Doug_Or From United States of America, joined Mar 2000, 3402 posts, RR: 3
Reply 8, posted (10 years 3 months 3 weeks 6 days 21 hours ago) and read 2688 times:
L-188 is right on with the 727s, and all 737 classics use pretty much the same model and coweling for their CFM56s. they use blocker doors to reverse fan air through the cascade vanes and out.... The coweling. sorry.
SlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 9, posted (10 years 3 months 3 weeks 6 days 9 hours ago) and read 2612 times:
US 737s have the standard CFM reverser system shown in the photo above. It would be difficult to spot the reversing mechanism when it is in the forward thrust mode, but the "translating sleeves" slide aft and the blocking doors get levered out into the fan shroud and direct fan air forward. It all disappears when the reversers stow.
Happiness is not seeing another trite Ste. Maarten photo all week long.
you can see the louvers that redirect the reverse thrust airflow. They are the grill-like areas on the right side of the no. 2 engine aft cowl (you can't see the louver on the left side in this picture), and the upper and lower louvers on the no. 3 engine aft cowl. As L-188 says, the pivoting reverser doors ("clamshells" or "buckets") are under the louvers. In forward thrust, the buckets pivot outward until they are flush with the inside of the exhaust, closing off the louvers and allowing the airflow to exit out the back of the engine. In reverse thrust, the buckets pivot inward until they meet. This opens the louvers, and at the same time blocks the airflow from exiting the rear of the engine. The airflow then has nowhere else to go, so flows out through the louvers. The louvers are angled forward, so this forward flowing air tends to push the aircraft aft, for reverse thrust. Regards,