XP-82 Twin Mustang Oshkosh 2019

[donna43]

[Vraciu]

It’s really too bad the Air Force stole the CAF’s away from them.   

[Vraciu]

You hear just a brief moment of the “Merlin Hum” at 1:52.5-1:54.   It is almost never captured on audio recordings even though your ears can hear it.

That’s a beautiful airplane in natural metal. 

[Chalenge]

That's not "Merlin hum" (Merlin Song) that I'm hearing. That's more exhaust + prop than anything. You're only about a month away from hearing the true song.

[Vraciu]

That's not "Merlin hum" (Merlin Song) that I'm hearing. That's more exhaust + prop than anything. You're only about a month away from hearing the true song.

It’s called the Merlin Hum because it’s unique to the Merlin. 

What causes it is irrelevant (though interesting) regarding the name because it’s only heard on Merlin engines, primarily the Mustang.    It is partly due to the Doppler effect which is why it is only briefly heard.    That Bob Hoover video I posted last year in your Sounds thread has a longer interval of it than this video.   

There’s also one in the Crazy Horse 2 aerobatic video but the music playing is in the way (and that woman won’t shut up with her narration so we can enjoy it). 

https://m.youtube.com/watch?v=aXqnCI1B_9g (0:12.8-0:13.9 and 0:38.5-0:39.9.   The exhaust masks it at 01:04) - It’s the humming not the popping of exhaust that follows it.   The sound system didn’t capture it very well but you can still hear it if you know what you’re looking for.   

https://m.youtube.com/watch?v=-IkSQF2MbSU (02:12.4-02-13.2 though the exhaust crackle is being picked up by the mic too much and is drowning it out.  02:37.5-02:40 is better.  03:46-47 catches it briefly as well.   It’s that thrum that moves down in pitch tone, very subtle in these recordings and quick.   Your ears hear it better in person.)

Merlin Hum is a unique and special sound that is highly transient.  Nobody who has heard it can forget it but sound equipment is terrible at capturing it. 

Looking forward to what you come up with.

[Chalenge]

Yeah. Still not Merlin Song. Maybe if you hummed it for me. 

[Vraciu]

Yeah. Still not Merlin Song. Maybe if you hummed it for me. 

It's the best part of Merlin music.   Gives me chills when I hear it.    I mimick it to my girlfriend and she laughs at me.    

It's a gently downward sloping sound--resonance is the word that springs to mind--only a Mustang truly makes.   (Spits do it some, too, maybe. I can't recall offhand, though.)

It's the single coolest noise from a Merlin there is.    That's why I hate modern airshow announcers.   They don't shut up so we can enjoy the sounds of the aircraft.   

[morfiend]

I was under the impression most the 82's were Allison powered,well except the prototypes and something like 20 P82b's.



  YMMV!


   

[Vraciu]

I was under the impression most the 82's were Allison powered,well except the prototypes and something like 20 P82b's.



  YMMV!


   

Early versions were Merlins.  The licensing was deemed too expensive so for the E through H they switched to Allisons and performance suffered.

[Devil 505]

Early versions were Merlins.  The licensing was deemed too expensive so for the E through H they switched to Allisons and performance suffered.

I never knew they went back to Allisons. I always disregarded the H model because it was so ugly.

[Vraciu]

I never knew they went back to Allisons. I always disregarded the H model because it was so ugly.

Yeah they did.   I am with you.  I hate the Allison nose on the Twin Mustang.   

It is an oft quoted factoid (which may be slightly incorrect)  that the F-82E is the one of the only frontline fighters that performed worse than its trainer version.

[Devil 505]

Yeah they did.   I am with you.  I hate the Allison nose on the Twin Mustang.   

It is an oft quoted factoid (which may be slightly incorrect)  that the F-82E is the one of the only frontline fighters that performed worse than its trainer version.

The nose is about the only thing that looks alright IMHO. The fuselage is smurfy. Totally ruins the lines of the A-D models.

[Vraciu]

The nose is about the only thing that looks alright IMHO. The fuselage is smurfy. Totally ruins the lines of the A-D models.

Oh, gawd no.   That Allison cowling has terrible lines.   Nowhere near as sleek as the Merlin.   

[Gman]

In one of the videos around of this plane, the pilot said that the Merlins had 18 to 1900 HP, a fair bit more than the standard P51D Merlin.  Anyone know how this affected performance, especially top speed at various altitudes, compared to the later Allison motors?

[Vraciu]

In one of the videos around of this plane, the pilot said that the Merlins had 18 to 1900 HP, a fair bit more than the standard P51D Merlin.  Anyone know how this affected performance, especially top speed at various altitudes, compared to the later Allison motors?

Max speed dropped from 482 mph (P-82B) to 460-465 mph (F-82E) and rate of climb was roughly 900 fpm less in the E.