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Post by Deleted on Dec 18, 2011 23:28:40 GMT 12
I was just wondering if anyone could tell me if the P-3 Orion needs a external APU on start up like the aircraft that it originated from does, the L-188 Electra? Cheers  |
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Post by baronbeeza on Dec 19, 2011 0:26:16 GMT 12
''''' a external APU ''' ..... that would be called a GPU.
Most aircraft of that size have an APU which has the added advantage of running the aircond when on the ground.
You mentioned start so in that case it will be an external GTC or the APU being used.
Normal procedure would be to use the APU, at least for the airlines... I could not speak for the Auckland Air Force.
The C-130 would look pretty stupid if you shut it down at some remote location and then couldn't start again.
The Newman's Dash 8's had no APU but with the small battery option. Ask the guys how convenient that was. They used a Ground Power pack wherever possible.
All other Dash 8's either have enough battery capacity or more likely an APU.
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Post by lesterpk on Dec 19, 2011 2:02:11 GMT 12
The P-3 has an APU which is used to provide air and power for starting engines. IIRC #2 is usually started first and then bleed air from it is used to start the others.
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Post by Deleted on Dec 19, 2011 9:21:55 GMT 12
"Without an APU installed, the aircraft required complete ground support. On gate arrival, an electric power source was plugged in before number four engine was shut down. The starting required an air source for the pneumatic starter." I found that on a website. www.enginehistory.org/the_making_of_a_flight_engineer_(5).shtml |
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Post by Deleted on Dec 19, 2011 10:56:26 GMT 12
Ok thanks |
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Post by baronbeeza on Dec 19, 2011 14:44:21 GMT 12
I should have mentioned that operating on a flight line and having an aircraft without an operable APU is a real pain. On most larger aircraft you are going to have to position and ready two external carts. An electrical rig with either 28/115 volts and an air cart of some description. The clip shows The RCAF guys readying a GTC for a C-130 start. One flight line I worked on had large compressed air bottles to enable a start if required. The trick was to ensure the rig was always ready. Aircraft of Dash 8 size and smaller, especially those with free turbines, normally have electrical starters anyway. Not quite the same drama. www.aerospaceweb.org/question/electronics/q0219.shtml |
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Post by Deleted on Dec 19, 2011 16:15:47 GMT 12
So does the C-130 not have a APU?
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Post by baronbeeza on Dec 19, 2011 17:09:32 GMT 12
All C-130's will have an APU.
That is not to say it is always working though.
The APU can supply electrical and air, it is possible you may have a bleed air issue though. The electrical part of them are less problematic.
I think you will find that most operators really look after the APU's. In many respects it can be the heart of the aircraft.
As I mentioned earlier, they can also operate the air-conditioning..... very important when operating in the tropics.
If the aircraft is to be on the ground for extended periods then they may choose to use a GTC cart. That may have been the case in the Canadian footage, - maybe an effort to get some heat into the cockpit.
The APU often draws fuel from one tank only so you can get a fuel imbalance with extended use.
We would have them running for about 2 to 3 hours each night on the 146's in Darwin.
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Post by raymond on Dec 19, 2011 17:12:10 GMT 12
The C130 originally has a GTC which could only be run on the ground however in the upgrade they are going through the GTC is being changed for an APU.
On 5 Sqn we used to have a "Huffer" which could start the engine if the APU failed and we used the same unit for the A4 (from memory)
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Post by baronbeeza on Dec 19, 2011 17:42:46 GMT 12
Oops, sorry. I could recall the noise... I just assumed it was an APU.
The older 737 had GTCP-85 APU's and somewhere along the way I had the impression the C-130 was similar. This from a guy that has no time for Wikipedia as well.
It may have come from the rating course notes... I would think.
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Post by Deane B on Dec 19, 2011 21:07:16 GMT 12
All C-130's will have an APU. That is not to say it is always working though. The APU can supply electrical and air, it is possible you may have a bleed air issue though. The electrical part of them are less problematic. I think you will find that most operators really look after the APU's. In many respects it can be the heart of the aircraft. As I mentioned earlier, they can also operate the air-conditioning..... very important when operating in the tropics. If the aircraft is to be on the ground for extended periods then they may choose to use a GTC cart. That may have been the case in the Canadian footage, - maybe an effort to get some heat into the cockpit. The APU often draws fuel from one tank only so you can get a fuel imbalance with extended use. We would have them running for about 2 to 3 hours each night on the 146's in Darwin. As has been pointed out, APU's provide air and electrical power (a generator is directly coupled to the APU engine). The Hercules GTC only provides air. However the GTC can provide power by using the air to drive a separate air turbine motor which couples to a generator. I'm pretty sure the C130 upgrade has the GTC's replaced with APU's. The big "huffer" cart at Whenuapai was a beast. Basically a big compressor driven by a massive V8 engine. Even so it had pretty pitiful output and a P3 engine start took about twice as long as normal. It blew up eventually and for a while the engine bay kept an APU on the test-rig to provide any required starts. In the late 90's an in-house built rig with an APU did the start duties, just the same as the start carts used at Ohakea. As a side note when Michael Jackson came out in 1996, both the 707's leased for the tour were parked at Whenuapai. One of them had no APU/GTC so the engine bay test-rig was used to start it on departure. It can't have been the most convenient aircraft to use on VIP tours when you need that kind of support everywhere you travel! Here are two other methods of starting P3 or C130 engines when there is no internal or external air supply (or if starter has failed ): 1. With prop feathered - accelerate down runway and then windmill start engine before aborting take off! I have seen that practiced. 2. Park another aircraft in front and have it run up it's engine(s). Use the propwash from that aircraft to do a windmill start on the affected aircraft That method has also been used! |
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Post by Deleted on Dec 19, 2011 21:45:10 GMT 12
Yup the ground cart thing was the external source i was talking about, thanks for the info guys, Baronbeeza you seem to have quite a knowledge of these things, what trade were you in the air force?
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Post by baronbeeza on Dec 19, 2011 21:57:24 GMT 12
That is all good stuff, thanks for that. I never had much to do with the C-130 or P-3. Certainly had plenty of exposure to the APU's fitted to a variety of aircraft though. Many are common, for example the Brasilia and BAe146 both commonly have GTCP-36-150 types. It was a long time ago that we worked about the GTCP-85 and I knew it was similar to the GTC for the A-4s. The 'P' stands for Power, electric power. Commonly the AC generator fitted is the same as the aircraft engine driven one. www.brittmetal.com/images/GTCP85%20Engine.gifwww.globalsecurity.org/military/systems/aircraft/c-130-car.htm |
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Post by bobajob on Dec 22, 2011 0:32:14 GMT 12
P3's & C130's in the RNZAF were self sufficient. APU or GTC with Generator gave them all the same overall flexibility and were able to start from the 24v Battery. then start the engines as above, the bleed air was also able to supply Airconditioning if I recall.
Bob Howard
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Post by phil on Dec 22, 2011 6:50:47 GMT 12
We used to use the GTCs to start the A4s, basically C-130 GTCs built in to a small trolley with a hose to hook up to the aircraft. They could be used to start an F-111 as well, but that took a lot of effort on the part of the little GTC and you had to watch the temps!
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Post by jonesy on Dec 22, 2011 8:56:49 GMT 12
Those GTC's could really howl! I think from memory were governed to 44,000 RPM? I remember doing a start-up on a F-111 at Ohakea, must have been about '91, we couldnt get the damn coupling off as more air was blowing back down the hose once the first engine had started! Progressively getting hotter, noisier and we were flapping around looking like dicks! Eventually managed to bash the quick-release to uncouple but not something I wanted to repeat!
I also worked at SEMS doing the scheduled maintenance on them. Great little units. bad on the ears....
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Post by phil on Dec 23, 2011 15:45:49 GMT 12
We used to get $5 extra a day adverse working conditions when we used them.
Ah those were the days, when they knew something was bad for you, but instead of fixing it they just paid you a bit more.
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Post by lesterpk on Dec 24, 2011 0:53:56 GMT 12
Yep, just like working in the paintshop, every day you were there was an extra $5. A nice little monthly bonus when we were poor AC/LAC's.
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Post by beagle on Dec 24, 2011 18:52:27 GMT 12
yes but that nice little bonus usually went straight to the Cpl's Club coffers
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Post by motoxjase on Dec 26, 2011 5:31:52 GMT 12
I was just wondering if anyone could tell me if the P-3 Orion needs a external APU on start up like the aircraft that it originated from does, the L-188 Electra? Cheers You being watching "Ice Pilots" havnt you?   |
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