Catch the Moment

The Pratt & Whitney PW1000G, also called the GTF, is a high-bypass geared turbofan engine family produced by Pratt & Whitney. After many demonstrators, the program was launched with the PW1200G on the Mitsubishi SpaceJet in March 2008, first flight tested in July 2008. Wikipedia

Bombardier CS100 / Airbus A220 Engine Start-up

Pratt & Whitney PW1523G

Widerøe Embraer E190 E2 registered LN-WEB departing from London Southend to Bergen on flight WF221. This is the 2nd Widerøe to leave Southend as part of Widerøe’s twice weekly Bergen service. Absolutely love the engine spool up from the PW1000G, they sound just awesome! Enjoy!

A topic that’s been spoken about a few times on these forums are that of the CSeries (A220) and it’s Pratt and Whitney GTF PW1000G engines. For those who haven’t heard these wonderful engines yet I’ll describe their quirky sounds. Upon spooling up you hear a low deep howling noise similar to that of the all time classic Vulcan howl (of course not as loud) You can also hear this sometimes on the approach, its when ever the engine is spooling up from idle.

Ever since I first spotted a CSeries aircraft that howling noise intrigued me. I wanted to find out exactly what causes it as it’s so unique. Over the years I came up with a few ideas of what caused it but have more less debunked each one. My thirst thought was the fact the fan has a 1:3 gear box meaning the 1st stage fan spins 1/3rd slower than the LP and HP compressors. I debunked this after hearing the PW800 engine found on new G500 and 600 business jets. The PW800 made an identical howl but does not use a gear system. One folk who commented on one of my Youtube videos said its the VSV (variable stator vanes) Before he mentioned that I had no idea what they were, essentially they’re guide vanes in the compressor which pivot depending on the power/air flow. He said that when these VSVs move that creates the difference in tone (the howl). I then found that VSV is a pretty common feature among Turbofan engines which brought me back to why does the GTF make the howl and no other engine does? Any way I found one more feature that could cause this noise. I read that the PW800 and PW1500G share the same core (hence the howling noise on both engines) I then read that these engines have a TALON Combustor. Which I later read the PW4000 also has, on some PW 777s you can hear a similar howl noise during the drop spool. So I thought being that these 3 engines create some kind of howl when spooling up could this be linked with the TALON combustor? Does the TALON combustor creat a unique howling noise when fuel is added?

I haven’t been on the A220 yet, so I don’t know exactly what howling you’re talking about. But when an engine is at idle or approaches idle or accelerates from idle, in addition to the aforementioned VSV, the VBV, the variable bleed valves, control the air flow through the compressor. When these valves open they can produce a quite noticeable deep hissing or growling sound. I found this to be quite noticeable on the A330 with PW4000 engines at idle. Maybe that’s the sound you’re referring to?

I appreciate this is a long post folks but I hope you guys can help me one my quest for the howl haha! So yes if anyone knows for sure what actually causes the GTF’s and PW800’s spool up howl that would be greatly appreciated! Many thanks!

https://www.airliners.net/forum/viewtopic.php?t=1459245

Let’s face it, the F-35A Lightning II howls and when it does, one cannot reminisce the howls of the legendary Avro Vulcan, which had a distinctive, haunting howl. Do you think it sounds like the Vulcan? Let us know your thoughts in the comments.

What causes the howl?
Well, this is is caused by the intakes of the aircraft as it takes in all the oxygen. But other factors can determine the overall sound in which the aircraft makes, such as the actual design of the wing and intake designs.

Based at RAF LAKENHEATH and flown by:
493d Fighter Squadron
495th Fighter Squadron

F-35A Specifications
Primary Function: Multirole fighter
Prime Contractor: Lockheed Martin
Power Plant: One Pratt & Whitney F135-PW-100 turbofan engine
Thrust: 43,000 pounds
Wingspan: 35 feet (10.7 meters)
Length: 51 feet (15.7 meters)
Height: 14 feet (4.38 meters)
Gs: +9G
Maximum Takeoff Weight: 70,000 pound class
Fuel Capacity: Internal: 18,498 pounds
Payload: 18,000 pounds (8,160 kilograms)
Speed: Mach 1.6 (~1,200 mph)
Range: More than 1,350 miles with internal fuel (1,200+ nautical miles), unlimited with aerial refueling
Ceiling: Above 50,000 feet (15 kilometers)
Armament: Internal and external capability. Munitions carried vary based on mission requirements.
Crew: One