Low level a400m - surprisingly quiet

[Zippee]

Just had one fly directly over our house at a very low level (was about 100ft higher than the screenshot which was taken a few seconds after).
I was just amazed how quiet this thing was, barely a whisper especially when compared to the old hercs it replaced

[aeropilot]

Zippee said:

Just had one fly directly over our house at a very low level (was about 100ft higher than the screenshot which was taken a few seconds after).
I was just amazed how quiet this thing was, barely a whisper especially when compared to the old hercs it replaced

They have known engines issues, perhaps it was flying on only two as when the bloody things fly over my house at 25-27000 ft they are very noisy and way louder than the Hercs are when flying over a bit lower at 20-23000ft.

[DavieBNL]

Must have been gliding...make a right whiney din every time they are over my place - which is quite often, very noticable sound.

[seabod91]

They are very loud usually. Normally look for a small twin turboprop going over at no more that a couple of thousand ft, then spot the a400 contrail’s at 35+.

Looks like there having fun though.

[LotusOmega375D]

Spot on. We get them over daily at 10,000ft. Easy to identify from the noise. I always go to the window and watch them fly over, cloud cover permitting. Some people on here like dissing them because they’re not a Hercules. Others take issue with our C-17 fleet, saying they’re over-used. What’s the point having aircraft if you don’t use them? Just ask Michael O’Leary. The Americans are still regularly flying 64 year old tankers, so surely there’s a few years left in our C-17s yet?

[aeropilot]

LotusOmega375D said:

The Americans are still regularly flying 64 year old tankers, so surely there’s a few years left in our C-17s yet?

That's because the USAF spent a fortune putting them through regular life cycle updates, including the re-engine programme etc., and well, the MOD has a habit of not doing that (which is why the E-3 Sentry was retired) plus at the moment there is no known mid-life update program for the C-17 as its not necessary for their fleet, as even their highest hour C-17 is about half of what all the RAF's small fleet is now at.

Funnily enough, the MOD contracted to do the update on the Herc's with all the fleet being fitted with brand new wing boxes, to see them to their OSD of 2035..............the first rebuilt one was only delivered back to the RAF just before Covid!!
And now in typical MOD fashion, we're flogging them off...

[Zippee]

aeropilot said:

They have known engines issues, perhaps it was flying on only two as when the bloody things fly over my house at 25-27000 ft they are very noisy and way louder than the Hercs are when flying over a bit lower at 20-23000ft.

Would have been flying from Marshalls in Cambridge - I was just surprised there was so little noise TBH and that it was so low over a town

[eharding]

Zippee said:

Just had one fly directly over our house at a very low level (was about 100ft higher than the screenshot which was taken a few seconds after).
I was just amazed how quiet this thing was, barely a whisper especially when compared to the old hercs it replaced

They cruise at over 400 knots at altitude, but they won't be doing anything like that at low level, hence have the engine power and propeller rpm significantly reduced, this reducing the noise footprint.

Edited by eharding on Friday 11th November 23:52

[swampy442]

Propeller RPM will be the same

[eharding]

swampy442 said:

Propeller RPM will be the same

Doesn't the TP400 have four speed settings - 655, 730, 842 and 860 rpm? A lot more trickery than a simple constant speed prop (although even just for those the overhaul bills are bad enough in my experience....)

[AndrewGP]

eharding said:

swampy442 said:

Propeller RPM will be the same

Doesn't the TP400 have four speed settings - 655, 730, 842 and 860 rpm? A lot more trickery than a simple constant speed prop (although even just for those the overhaul bills are bad enough in my experience....)

Correct, although it actually has another setting as well at 690rpm. 655 and 690 are used at higher cruise altitudes when the 'Low Noise Cruise' mode is selected. The FADEC will decide which rpm is scheduled based on the altitude.