Yesterday afternoon I thought a nearby neighbour was using very noisy garden machinery until I realized the noise was constant and gradually getting louder. It was a considerable time before I at last saw a light helicopter flying directly towards me and as it passed overhead it looked like a Bell 206 LongRanger. A check on Flightradar 24 showed it to be G-RAZE, apparently a Bell 407 which was doing an clockwise trip around London and passed overhead at about 1500ft AGL and 130kts. It was by far the noisiest helicopter I have ever heard yet the LongRanger was such a smooth quiet aircraft albeit some15-20kts slower. I guess outside noise considerations come pretty low on the manufacturer's list.

(There is a short YouTube video of the same aircraft overflying Farnborough a year ago so I guess it's not just me)

We regularly get S-76 helicopters flying over us, G-ROON being a frequent visitor, but they never appear on ADSB. Talking of noise, on the odd occasion we get the HM Coastguard helicopters over this way and they are noisy, but I bet to anyone awaiting rescue it must sound like angels singing.

The US Army conducted some tests to determine acoustic characteristics for the Chinook at several military bases.

https://www.chinook-helicopter.com/T...elicopters.pdf

I can't help suspect they were modified in some way to be quiet. It was a still night and my hearing and eyes were attuned to the shooting conditions.

I felt and smelled the downwash. I would estimate I had 20 seconds notice of their overflight.

WWW

Nothing modified - the blades are the same. Boeing were trying to progress the composite ACRB (Advanced Chinook Rotor Blade) as part of the Block II CH-47F upgrade, and that may have different noise characteristics as they featured swept tips (to smooth airflow separation - they are similar in concept to the blades proposed for the RAH-66 IIRC). However, despite showing promising improvements in lift, it vibrated badly and has, last I heard, been shelved for now. Many moons ago at Odiham we were instructed to slow down to less than 120kts inside the MATZ to be 'good neighbours' as it reduced noise (albeit at the 'cost' of us being airborne longer…). AT 90kts, it's broadly min power speed so neither engine nor rotor/transmission system are under high loading, and at low level the footprint is appreciably smaller. Careful planning and the use of wind and topography can yield some very interesting results, and you can get surprisingly close sometimes (especially at 50ft) before you're heard - and as MGD noted earlier, reflected noise can also help to confuse an opponent.

Four miles away would have been rather more audible and I would probably have seen them! During lockdown when there was virtually no traffic about and it really was quiet up on the common I could hear a Lynx following the Thames heli lane. In the right conditions, noise can reach sensitive ears a long way...

Just watched a Chinook going downhill at quite a rate of nots with a load slung under the rear of the aircraft.
Does the chinook have multiple load points underneath? Always thought they picked stuff up in the middle.

3 hooks iirc, different points to allow for different CG combinations and attaching more than one load at a time I guess

RAF PR image

Every RAF Chinook trainee aircrew - pilots and loadies - had to qualify on triple-USLs prior to finishing the OCU course. A favourite exercise was with the RA 105mm light gun, where you land to pick up the gun crew then lift to the hover and pick up the ammunition, the 1-tonne LR and the gun. I was surprised to learn that in the US Army at the time I was operating on type (1989-1997), carrying USLs was considered an advanced skill that was covered after pilots had started Sqn service; don't know if that was true.

T&B, I think you are correct, during GW1 we met US Army CH47 crews based in Italy that weren’t “sling load qualified” although it did make us wonder what they did if they didn’t trash haul like us!

They saved themselves from what seemed like an eternity dragging an underslung minidigger across West Falkland at 40kts in a 50Kt headwind.

Hmm, that would take an eternity! 😊

Mog

Which is why we sat and played uckers remained at MPA fulfilling other important tasks on such days :E - the standby RADAR for the W Falkland sites was a particular pain.

Conversely, with an average wind we could lift off from W Falkland with a full ISO underneath at the same time as a Sea King lifted from North Arm (E Falkland, SW of the airfield) and be half-way through shutdown checks having deposited the load in the appropriate place before the SQ arrived in the hover at MPA.

T&B-glad you brought up that sling training anomaly. Example: in 1963 all pilots being trained got sling training in the basic course ( H-19s or H-34s ).
In 1977-8 we trained the trainers at Ft Rucker ( the new Instructor Pilots for the UH-60 ) in slings. However on a trip down there over a year or two later, they had moved that training to the units. Maybe some senior IP can pass along the thinking associated with that move??