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Posted: 3/19/2006 11:49:25 AM EDT
What is the purpose of the cut-away center section of the engine nacelle? It is open to the outside and has a white grid covering:
 This C-16 was minty new with 400 flight hours:  A HUD on a cargo plane? What will they think of next!  Here I am at the controls, preparing to take off. Always look like confident in front of the troops, even if you don't know what the bleep you are doing! 
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Posted: 3/19/2006 11:50:53 AM EDT
[#1]
not sure about the white grate on the engine nacelles, but the HUD is a handy adaptation for low level night drops like the C-17 is designed to do.
IIRC, they are putting them in the new J model C-130 as well |
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Posted: 3/19/2006 11:53:07 AM EDT
[#2]
talk to brohawk he is a c-17 guy
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Posted: 3/19/2006 11:55:00 AM EDT
[#3]
Engine thrust reverser.
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Posted: 3/19/2006 11:56:04 AM EDT
[#4]
The thrust reversers are just open.
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Posted: 3/19/2006 12:01:38 PM EDT
[#5]
The white grates are where the fan exhaust is ducted.
The grates on the core (ass end) is where the cort exhaust is ducted.
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Posted: 3/19/2006 12:16:17 PM EDT
[#6]
I've heard the C-17 can lose altitude at over 20,000ft/min on a tactical approach!!!!!
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Posted: 3/19/2006 12:27:45 PM EDT
[#7]
Drop the flaps and gear, push the throttles past the gate into reverse, lower the nose and trim the aircraft up and there ya go.... |
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Posted: 3/19/2006 12:29:53 PM EDT
[#8]
Flown on one to Rota in 1996...Awesome plane.
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Posted: 3/19/2006 12:45:43 PM EDT
[#9]
If they did that will we were jumping the crew chief would be cleaning up alot of puke
 FREE
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Posted: 3/19/2006 12:53:14 PM EDT
[#10]
Is that possible? In flight, no touch down swithes activated? Just curious, or are the stops in the throttle quadrant all that's there? |
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Posted: 3/19/2006 12:57:12 PM EDT
[#11]
Shouldn't be able to move throttles into reverse unless you have gear down & weight on wheels.
He probably meant to say throttles to flight idle. |
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Posted: 3/19/2006 12:58:18 PM EDT
[#12]
Does that mean the whole rear half of the nacelle slides rearward to expose the grate, and that in regular thrust mode it slides forward so that the grate is covered and the nacelle is smooth and un-interrupted? |
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Posted: 3/19/2006 1:03:39 PM EDT
[#13]
Yes. When you fly next time get a seat near the engine, just in front of it. You can see the thrust reversers work when they land. The rear cowling will slide backwards and you can hear and feel the pilots give more rpms. The spoilers and brakes also slow the plane. Its quite dramatic how well they work. Suposedly one of those suckers deployed in flight on a 767 causing it crash. |
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Posted: 3/19/2006 1:07:21 PM EDT
[#14]
In my book that's something the load had to fix. |
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Posted: 3/19/2006 1:07:52 PM EDT
[#15]
Heres a C-130 on a combat approach.Hold on to yer lunch!
 http://www.alexisparkinn.com/photogallery/Videos/2006_c130_amazing_approach.wmv |
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Posted: 3/19/2006 1:11:57 PM EDT
[#16]
Made hot… www.alexisparkinn.com/photogallery/Videos/2006_c130_amazing_approach.wmv |
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Posted: 3/19/2006 1:16:07 PM EDT
[#17]
Heading for the ground at 227 MPH....the pucker factor must be intense. Either your ass will clamp onto the seat and not let go for anything, or it'll go into "emergency fuel dump mode". That's considerably faster than a human body can fall through the air without training and practice in accelerated descents. Freaking WOW. |
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Posted: 3/19/2006 1:21:21 PM EDT
[#18]
Quoted:
If they did that will we were jumping the FREE Fixed it for ya! Crew Chief's don't clean up puke when there is at least one jumpmaster aboard. We were dropping troops at Pope/Ft. Bragg (back in 93/94) in C-130Es, some of the troops started puking in between the seats and on the floor. When we landed the female jumpmater aboard gathered her gear and started to deplane; my DCC explained that since the puke didn't leave with her jumpers, she was going to clean it up. She really didn't seem that upset, just cleaned it up and moved on. Can't say I ever wanted to jump out of an airplane; God bless those crazy bastards that do! B_S |
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Posted: 3/19/2006 1:53:39 PM EDT
[#19]
Actually Vito is right, they will go into reverse in flight. They decend at about 300 knots btw, from what the -1 says, and what the crews tell me. It's pretty messy in the cabin when they do hard TAC-Ds and all the chains come out of their lockers, all the rails pop up, and all the dirt in the floor is ON the floor.  The crew was gracious enough to clean up their mess though, we just had to grab the shop vac for them.  The engines were designed to reverse in flight specifically for TAC-Ds, in fact, two of the engines on a C-5 will do it too (I think its the inboards, but not sure). The core thrust reversers don't actually "reverse" much at all, but they make engine running cargo loading/offloading safer, less chance of getting cooked behind the motors. Some of our guys that were hauling jearheads for the tsunami relief said they goaded them into "doing something cool" so they did a really gnarly TAC-D and had about half the guys puking. ETA: The worst thing about T/Rs is standing in front of them in the desert, when its 130* ambient and they heat it up even more, waiting to marshall them out (backwards, of course). It'll make an unbearable day even worse.  It is cool to be able to back them up as far as we need to though, gives us some very "interesting" parking options, like putting 12 of them where 4 were supposed to go.
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Posted: 3/19/2006 1:56:01 PM EDT
[#20]
HOLY HELL |
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Posted: 3/19/2006 3:16:35 PM EDT
[#21]
IIRC there is no spent exhaust gas on some reversers, just the air coming off the compressor section.
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Posted: 3/19/2006 3:41:23 PM EDT
[#22]
Actually, it's air from the fan. The large fan you see looking into the front of the engine. In a modern high bypass turbofan engine, the majority of the engines thrust is produced by this fan. Cascade thrust reversers simply re-direct the path of the fan air. The clamshell reversers close over the exhaust, and redirect the exhaust gasses, as well as the fan air. |
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Posted: 3/19/2006 3:44:26 PM EDT
[#23]
I don't get it. Wouldn't the thrust just come out radially from the engine through the grate, not vectored towards the rear?
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Posted: 3/19/2006 3:56:08 PM EDT
[#24]
The reversers are deployed, the air is redirected through the grates, vectored toward the front of the aircraft. So its slowing it down. The rear exhaust is closed off. You need to see DC9. The reversers are two halves of the rear cowling. The split like a clam shell and make a v toward the rear. The exhaust hits the inside of the V and is redirected forward. A fan has the same concept except the mechanism is inside. |
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Posted: 3/19/2006 3:59:51 PM EDT
[#25]
The big deal is that since the air is no longer going out the back of the engine, it is no longer pushing you along. The smaller benefit, is that since the air is ducted forward, it now slows the airplane down. The airplane I now fly, has the clamshell type of reversers, and simply opening them provides you with lots of deceleration. The last airplane I flew, had the cascade type of reversers. We had to select maximum reverse thrust to feel much deceleration. None of the civil transport airplanes I've ever flown could use the reverse in the air, so I've never experienced that. But it must be quite a ride. When we train in the Simulator, for a reverser deployment in flight, the whole thing shakes like crazy. I cant imagine opening two of them, and taking the express elevator down. |
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Posted: 3/19/2006 4:28:23 PM EDT
[#26]
Years ago, a Russian transport aircraft crashed, killing all on board.
The investigation found that the pilot had allowed his young son into the cockpit and had allowed him to sit in the captain's position. The kid accidentally turned on the thrust reversers, IIRC, and the crew could not regain control in time to save the aircraft. |
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Posted: 3/19/2006 4:28:28 PM EDT
[#27]
The C-5 doesn't use the TRs for TAC-Ds. The standard saying when using them was not to use them unless you're ready to stay there for at least 5 days. The rumor is that the C-5 crash at Ramstein during GW1 was caused by a TR extending at takeoff thrust causing the aircraft to flip over and crash. Most of the old-heads would never use the TRs unless they could be inspected on the ground prior to taking off. Spooky |
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Posted: 3/19/2006 4:30:01 PM EDT
[#28]
The grates look very clean; so the thrust that comes out here is just uncombusted air?
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Posted: 3/19/2006 4:35:36 PM EDT
[#29]
That's correct. The air from the bypass fan never takes part in any combustion. Depending on the engine, less than 1/2 of the air that goes in the front ever sees fuel or fire. The rest of the air bypasses the compressor section. That's where the term hi-bypass comes from. |
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Posted: 3/19/2006 4:42:17 PM EDT
[#30]
Do you guys bother to READ my posts?  
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Posted: 3/19/2006 4:43:58 PM EDT
[#31]
<ding> This is your Captain speaking. We are going to begin our approach so please secure your belongings and I am going to turn on the seat belt light. Thank you for flying Southwest. |
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Posted: 3/19/2006 4:50:38 PM EDT
[#32]
Forgive me for being dense, but does the air go backwards through the fan, in through the grate, out through the front inlet cowling? Surely the fan does not go into reverse...or do the fan blades have variable pitch, like a propeller?
Hi KA3B! Someone help this guy too! |
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Posted: 3/19/2006 4:56:09 PM EDT
[#33]
The CFM-56-2A that the Navy's E-6B uses has translating engine cowls that are part of the thrust reverse system.
They can not be deployed in flight. 
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Posted: 3/19/2006 4:59:51 PM EDT
[#34]
The bypass air that the fan produces (hehe, follow along with that) is blocked by a set of "doors" or a "translating cowl" that blocks the bypass air from going out the ass-end and reverses the bypass air to go out the OPEN GRATE of the cowling. The air path has been reversed. Any questions? Jet engine 101 was held last year.  |
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Posted: 3/19/2006 5:00:21 PM EDT
[#35]
Quoted:
Forgive me for being dense, but does the air go backwards through the fan, in through the grate, out through the front inlet cowling? Surely the fan does not go into reverse...or do the fan blades have variable pitch, like a propeller? No, the reverser grates are aft of the fan. So the air still goes thru the fan. When you select reverse, the cowls open (exposing the grates) and the inside of the nacelle (between the engine, and the nacelle) are blocked off. The only way out for the air then is thru the grates. Think about it like this. The actual "power" part of the engine is much smaller than the nacelle, let's just say half as big. The fan air normally just flows around the "engine", and out the back. Where it mixes with the hot exhaust air. The reversers just re-direct that "outside air". The engine and fan never change directions. IIRC, certain versions of the DC-8, and the concorde could use reverse in flight as well. |
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Posted: 3/19/2006 5:05:27 PM EDT
[#36]
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Posted: 3/19/2006 5:08:01 PM EDT
[#37]
It's kind of hard to see, but gives you the general idea.
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Posted: 3/19/2006 5:09:06 PM EDT
[#38]
It's all explained right here....
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Posted: 3/19/2006 5:19:43 PM EDT
[#39]
This is true. I've been on C-17's during several tactical approaches. Almost as much fun as going in reverse down the runway at a high rate of speed.
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Posted: 3/19/2006 5:26:01 PM EDT
[#40]
They can do that?
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Posted: 3/19/2006 5:29:14 PM EDT
[#41]
.
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Posted: 3/19/2006 6:57:32 PM EDT
[#42]
Is the number REALLY 20Kft/min? Hell, the space shuttle does 14Kft/min at 300KN. This thing can drop faster in a controlled fashion than the space shuttle?
Who's got a -1 page they can post on that? aa |
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Posted: 3/19/2006 7:11:02 PM EDT
[#43]
They don't use max reverse in flight for the tactical descents, just flight idle.
Wicked shit. Oh, the E-3 can get up to around 9,000 fpm descent with speed brakes up and gear down. 
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Posted: 3/19/2006 7:35:10 PM EDT
[#44]
I watched one backing up a slope in front of a hanger in Saudi once. It was amazing to watch the vortex of sand being sucked into the engines and being spit out as black smoke. From what I hear the sand doesn't do too much damage either. I had to clean up the mess on the taxiway and runway at Ft Lewis when that female pilot destroyed the engines on the C-17 by reving it up with engines hanging out off of the paved surface.
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Posted: 3/19/2006 7:51:05 PM EDT
[#45]
Looks like somebody else was at Mather today too.
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Posted: 3/19/2006 7:56:48 PM EDT
[#46]
Fixed it for ya, they do open the reversers. |
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Posted: 3/19/2006 8:00:11 PM EDT
[#47]
Yeah that one down at Gray Field really did a number on those motors. Many damaged fan blades and stators. The sand definitely doesn't do much to these motors, the fan blades pretty much sling it to the outside so it doesn't get in the compressor, and the fan blades are pretty tough. I have seen some pretty dang big dings and dents that nobody knew where there till they inspected it, birds and big rocks I guess. For the naysayers, I will get a copy of the -1 for tactical decents, and translate only the relevant parts here. (tomorrow, I just got home from work)
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Posted: 3/19/2006 8:57:10 PM EDT
[#48]
I found this Tactical Descent procedure using only open source means (google, of course), so don't yell about opsec please.
 17.12. Tactical Descents. If necessary, reverse engine idle thrust and speed brakes can be used to obtain rapid descents from high altitudes. Initial descent rates of over 12,000 fpm may be achieved. Tactical descents are always flown single ship and use of the flight director for guidance is recommended. 17.12.1. High-Speed Rapid Descent. Use the following procedures: 17.12.1.1. Select "320 PCH" (or .800 Mach when above 28,000 feet) on the AFCS panel. Disconnect the autopilot, extend the speedbrakes, and deploy reverse idle thrust (if desired). ("Speedbrakes" means all spoilers fully deployed and partial flaps, all automatically programmed through the flight control system) 17.12.1.2. The PF follows the pitch bar to maintain desired speed, and follows the roll bar for lateral navigation guidance. 17.12.1.3. At the briefed "start level off" point, the PNF will make an advisory call to the PF. The level off should be initiated approximately 2,000 feet above the desired altitude. 17.12.1.4. Stow thrust reversers (if used) and speed brakes prior to leveling off. Select desired speed (IAS on THR) on the AFCS panel and establish en route airspeed. |
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Posted: 3/19/2006 9:01:47 PM EDT
[#49]
The simulated A-10 attack was bitchin' And the Heritage flight when it flew in formation with the P-51 was amazing as well. I grew up on that base 
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Posted: 3/19/2006 9:06:48 PM EDT
[#50]
Ha, that was cool. You guys think that is scary? Shit, Id like to do that in the Cessna I fly.
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