The Merlin "Whistle"

[dhenriques]

Hi everyone;

In perusing the forums concerning Mustang sounds, I've come across several postings concerning a desire to hear the famous P51 "whistle" in soundsets.
A2A has produced by far the most authentic sound set for the Mustang I have yet heard done for flight simulator.
Just a few words about the "famous whistle" if I may.

When you attend an air show and hear a Mustang going by you at low altitude, what you are actually hearing is a whole lot more than the Merlin.
The famous sound of the Mustang changes as it's heard on the ground due to various and constantly changing factors that include the following;
1. The power setting; during a display demo maneuver pass most likely up at METO (46" 2700RPM)
2. The outside air temperature and density altitude at the time of the pass.
3 Most importantly, the sound you are hearing is augmented by the air passing through the radiators beneath the airplane coupled with the above. There are 2 doors under the scoop. One controls the oil temperature and the other the coolant temperature.Usually, during a demonstration where you might be viewing a low flying Mustang , the oil and coolant shutters are selected automatic, but if the temps are high due to extended power settings at Meto or above, the pilot might have both shutter doors open manually. The actual position of these two shutter doors at any given time will change the sound you are hearing and most certainly are responsible in large part for the famous Mustang "whistle".

Just a few words here from an old hand in the hope that those of you enjoying the magnificent work on the 51 done by A2A will come to appreciate how difficult it is to produce a complete Mustang soundset.


Dudley Henriques

[Scott - A2A]

Dudley,

We'll be recording some p51 fly-by's in the coming weeks. I will ask the pilot to open those doors and we'll grab that sound. This is something I think we can re-create using accusim. Thanks for the info.

Scott.

[dhenriques]

Dudley,

We'll be recording some p51 fly-by's in the coming weeks. I will ask the pilot to open those doors and we'll grab that sound. This is something I think we can re-create using accusim. Thanks for the info.

Scott.

Hi Scott;

Normally both doors will be set on automatic and will be open or closed as that setting dictates. This is why the sound of the 51 can change from time to time as you hear it. On a cold day you might get one sound and on a hot day another slightly different sound.
I've always found the famous 51 "whistle" to be the most prevalent on hot days with the doors open and affecting the airflow through the radiators.
Good luck with your photo shoot!
Dudley

[DogTailRed2]

Is this 'Whistle' the same as, what I have heard referred to as the Mustang blue note?
It's a howl made by the radiator during high speed passes etc. You would hear this as a spectator, not sure if you would hear it from the cockpit.

[DHenriques_]

Is this 'Whistle' the same as, what I have heard referred to as the Mustang blue note?
It's a howl made by the radiator during high speed passes etc. You would hear this as a spectator, not sure if you would hear it from the cockpit.

You're right. The sound that is so distinctive as belonging to the 51 is not the sound you hear flying the airplane.
(Actually, it's hard to hear ANYTHING flying the Mustang ))
-DH

[DogTailRed2]

It would be nice to capture the crackling and popping Merlins do when throttling back.

[ICDP]

I can't find the source right now but I have read the whistle was actually due to airflow/around through the gun ports.

[skunker]

I can't find the source right now but I have read the whistle was actually due to airflow/around through the gun ports.

Sort of like when you blow air into the static port for the stall horn of a Cessna 150? It whistles.

[DHenriques_]

I can't find the source right now but I have read the whistle was actually due to airflow/around through the gun ports.

Our 51 had custom plugs in the gun ports. Whistled just fine )

Dudley Henriques

[VFR Reviews]

Haha, that's cheating

Perhaps the original pilots had something similar to intimidate the enemies

[Bradburger]

I can't find the source right now but I have read the whistle was actually

due to airflow/around through the gun ports.

Our 51 had custom plugs in the gun ports. Whistled just fine.

I think there might be some confusion here between the Mustang "whistle" & Mustang
"whine" or "scream"!

If you listen closely to restored Mustangs that have no gun ports or them blanked off,
there is a faint whistle, but it's nowhere near as pronounced or the same as the "whine"
or "scream" on those aircraft with opened ones, which clearly occurs during airspeed and angle of attack changes, and seems to mask the whistle, which would appear to be from air going through the radiator as has been suggested.

Take a listen to these videos and compare the sound from machines with open gun ports
and those with none or blanked off.

First up, The Scandanvian Historic Flights example with no gun ports.

http://www.youtube.com/watch?v=5hARupaw ... annel_page

Now two P-51's in the same video, first G-SIRR with no guns ports, the second G-HAEC
(now Rob Davie's 'Big Beautiful Doll') with them.

http://www.youtube.com/watch?v=rRB8fLF6 ... annel_page

Now G-BTCD 'Ferocious Frankie', (formally 'Moose/Candymanwith TFC) during a display
at Old Warden, which has them and bomb/droptank racks.

http://www.youtube.com/watch?v=i1Eknnzg ... annel_page

Quite a difference eh?

I overheard the pilot of 'Ferocious Frankie' talking to some spectators after the above
display, saying how he had to be careful whilst he was holding (he was the 'surpirse'
item that opened the show) because even small AoA changes can cause the "scream".

Cheers

Paul

[letsgetrowdy]

That noise sure sends a shiver down your shine, huh?

Big Beautiful Doll's noise is the most impressive by far. Has a kinda roar to it, as well as the whistle.

If you watch this video clip, you can see a scene from the 1989 movie "Empire of the Sun", in which Ray Hanna flew the OFMC P-51, painted as "Tugboat" (now "Ferocious Frankie") and Hoof Proudfoot flew "Miss Wong from Hong Kong" (now Big Beautiful Doll). The 'Doll's noise is the most promenant and loudest however.

[youtube]http://www.youtube.com/watch?v=tztl6ZEjrw4[/youtube]

[Bradburger]

Big Beautiful Doll is indeed a nice 'screamer'!

Here's BBD again along with Maurice Hammond's 'Janie' (also a 'screamer') at Headcorn proms a few years ago.

http://www.airshowbuzz.com/videos/view.php?v=b50c1668

Cheers

Paul

[letsgetrowdy]

I saw "Janie" at Woodchurch, in Kent in 2005. It also flew at duet with BBD on that occasion aswell. BBD and Rob Davies' other warbirds have been taken to Berlin temporarily
do you know if Woodchurch is having a show this year?

[JamesB]

I was also told that in some part at least it is caused by the gun ports and yes its basically air passing over them causing the whistle noise, like blowing over the top of a bottle. I'm sure that the radiator and associated flaps also cause a noise but as pointed out on Mustangs with open gun ports you hear the noise when the aircaft is pulling tight turns or loops where the air is being dragged over the leading edge. I used to work on the North Weald Fighter Meet and Intrepid Aviation had a gorgeous P-51 it had open gun ports and I was told by its main pilot Norman Lees that much of the noise was caused by the gun ports.