Noise at Brize Norton
Is the 'J' noisier outside as well as inside than the 'K' ?
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Having flown a type without a critical engine ie the props turn in different directions counter rotating.
The noise on the aircraft with counter rotating props is less than when the props both go in the same direction.
The A400 also has the downward sweep of the blade further away from the fuselage with the engine in the way of the prop wash. Where as we had the downward swipe next to the fuselage to reduce the moment with engine failure.
The noise on the aircraft with counter rotating props is less than when the props both go in the same direction.
The A400 also has the downward sweep of the blade further away from the fuselage with the engine in the way of the prop wash. Where as we had the downward swipe next to the fuselage to reduce the moment with engine failure.
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Originally Posted by Ksimboy
vibrations in the seats in the area of the props cause whitecaps in your coffee ...
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Haltonapp asked
So what is it?
Rgds SOS
Start up, to taxy, seems to take for ever for an Albert, I'm sure there must be a technical reason why it takes so long.
Rgds SOS
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Start up, to taxy, seems to take for ever for an Albert, I'm sure there must be a technical reason why it takes so long.
So what is it?
But as the jets are just whispering at idle compared to the props thrashing around, even at 70% (low-speed ground idle), it probably just seems longer to bystanders........
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I did some work on this issue when I was seconded to Project Future Brize circa 2010. As has already been alluded to it is frequency and direction that causes the problem!
The J is quieter in decibels than the VC-10, but the frequency means the noise carries much further, plus it travel in almost every direction in almost equal strength so you are subject to it no matter which way the aircraft is pointing.
The J also requires a lot of engine runs. A sample from a winter and a summer month showed that out of the total number of engine runs done at BZN & LYN about 60% were C-130J runs, and a significantly higher number were high power runs. It was all to do with the making sure the various electro gizmos were talking, so even replacing a throttle lever meant an engine run had to be carried out. Just the way the manuals were written. There was a plan to build a big burn a la on the sports fields at LYN out of a load of hardcore left over from demolition but this was vetoed on cost grounds (£500,000 I think). Was going to be between the south side bays and the runway. Not sure how effective it would've been.
The J is quieter in decibels than the VC-10, but the frequency means the noise carries much further, plus it travel in almost every direction in almost equal strength so you are subject to it no matter which way the aircraft is pointing.
The J also requires a lot of engine runs. A sample from a winter and a summer month showed that out of the total number of engine runs done at BZN & LYN about 60% were C-130J runs, and a significantly higher number were high power runs. It was all to do with the making sure the various electro gizmos were talking, so even replacing a throttle lever meant an engine run had to be carried out. Just the way the manuals were written. There was a plan to build a big burn a la on the sports fields at LYN out of a load of hardcore left over from demolition but this was vetoed on cost grounds (£500,000 I think). Was going to be between the south side bays and the runway. Not sure how effective it would've been.
Last edited by course_profile; 2nd Oct 2013 at 23:51.
It takes about 10 mins to run the checks from starting the APU to taxi, covering engine start (approx. 1 min each), anti-icing (with engines run at 100% to provide sufficient bleed air for the check), stall protection & autopilot checks. Not unduly long but I guess a bit longer than a jet which starts its engines as its pushed back & is probably ready to taxy a wee bit sooner.
ksimboy,
thanks for the reply. When I was with the HEART we visited Abbey Wood to talk to the J office. When asked about the relative noise levels of the J and K we gained the clear impression that inside at least the J would be worse than the K. As I retired from the RAF before the J entered service I did not have a chance to check on this.
When I was on 30 Sqn I 'minded' a university team who were researching the internal noise levels on the K. I have a copy of the report somewhere but remember that the opening para went something like this 'the noise in the Hercules cargo compartment is like being in a disco with a pneumatic drill operating nearby' !
Sounds like the J has a couple of such drills.
thanks for the reply. When I was with the HEART we visited Abbey Wood to talk to the J office. When asked about the relative noise levels of the J and K we gained the clear impression that inside at least the J would be worse than the K. As I retired from the RAF before the J entered service I did not have a chance to check on this.
When I was on 30 Sqn I 'minded' a university team who were researching the internal noise levels on the K. I have a copy of the report somewhere but remember that the opening para went something like this 'the noise in the Hercules cargo compartment is like being in a disco with a pneumatic drill operating nearby' !
Sounds like the J has a couple of such drills.
ancientaviator62
Were those noise measurements conducted in 1994? If so I think you will find the team was from Farnborough ie DRA/IAM.
Regarding external noise levels and especially due to engine runs then they will inevitably lead to noise complaints. The problem is largely due to the tonal characteristics and unlike a departure the noise is present for much longer.
Has BZN looked at a large scale noise pen to conduct the engine runs. If you really want to control the noise then a large enclosure would suffice but I imagine it would be very expensive to build. Was there a facility such as this at Lyneham. I'm tempted to ask, as a civvy of course, why was Lyneham closed in the first place but that might be contentious.
BBK
Were those noise measurements conducted in 1994? If so I think you will find the team was from Farnborough ie DRA/IAM.
Regarding external noise levels and especially due to engine runs then they will inevitably lead to noise complaints. The problem is largely due to the tonal characteristics and unlike a departure the noise is present for much longer.
Has BZN looked at a large scale noise pen to conduct the engine runs. If you really want to control the noise then a large enclosure would suffice but I imagine it would be very expensive to build. Was there a facility such as this at Lyneham. I'm tempted to ask, as a civvy of course, why was Lyneham closed in the first place but that might be contentious.
BBK
BBK,
amazingly I found my copy of the report in the first box in the loft.
The report is dated 3 September 1991 and the author was W.R. Hodson.
I think they were from a university.
When with the HEART at Wyton, I tracked down a report by Hoare, Lea and partners dated 30 July 1996 into a trial carried out on noise in the K . I do not have a copy of that report, but seem to recall it was performed at Marshalls. You mention a trial carried out in 1994, so that is at least three trials into the problem ! During my time on the K nothing was done to reduce the effects of noise on the a/c.
amazingly I found my copy of the report in the first box in the loft.
The report is dated 3 September 1991 and the author was W.R. Hodson.
I think they were from a university.
When with the HEART at Wyton, I tracked down a report by Hoare, Lea and partners dated 30 July 1996 into a trial carried out on noise in the K . I do not have a copy of that report, but seem to recall it was performed at Marshalls. You mention a trial carried out in 1994, so that is at least three trials into the problem ! During my time on the K nothing was done to reduce the effects of noise on the a/c.
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BBK,
Yes, several infrastructure options were looked into. All far too expensive and also difficult to work out where they would go. It also creates a logistical nightmare for the engineers. If you can only engine run in one location but need a lot of engine runs doing it drains the man power and man hours through towing the aircraft back and forth. Nothing would ever have been achieved.
The Yanks had just build something at Mildenhall for their MC-130s and this was investigated but again, way too expensive.
Yes, several infrastructure options were looked into. All far too expensive and also difficult to work out where they would go. It also creates a logistical nightmare for the engineers. If you can only engine run in one location but need a lot of engine runs doing it drains the man power and man hours through towing the aircraft back and forth. Nothing would ever have been achieved.
The Yanks had just build something at Mildenhall for their MC-130s and this was investigated but again, way too expensive.
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The civvy operated ones I see around in the Horn of Africa on UN contracts manage to get airborne pretty quickly. Maybe it helps that they have to pay for the fuel!
The 'civvy operated' ones aren't J models so you're not comparing like with like, and anyway it's not as if crews loiter around doing unnecessary checks on a whim, they're working through the checklist as provided by the manufacturer. Besides, an extra couple of minutes doing the checks properly is not going to make a big dent on the fuel burn of a leg to Akrotiri for example.
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You infer civilian operators wing it and use their checklists for toilet paper, they don't on both scores.
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No, he implied that the civvies are flying older models of aircraft (I believe that there is no civvy J) and use the checklists provided by Mr Lockheed rather than those created by Qinetiq/ Boscombe which may or may not be physically twice as thick.
Last edited by kharmael; 4th Oct 2013 at 05:19.