PDA

View Full Version : Merlin engines



blazer-glory
06-10-2006, 10:56 AM
What is it exactly that gives the Merlin engine that distinctive sound?

Low_Flyer_MkVb
06-10-2006, 11:01 AM
Why the noise, of course. http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif Could have sworn one flew ovew the house a couple of hours ago...

Treat this as a well-meaning bump.

Jumoschlong
06-10-2006, 01:22 PM
The sound qualities of an internal combustion engine are dependent on the number of cylinders it has, it's rpm, compression ratio, type of aspiration(carbureted, fuel injected, supercharged or turbocharged, and it's rpm operating range.

The number of cylinders vs. the rpm operating range will determine the number of "pops" per second, or the "frequency" of the sound.
The higher the compression ratio, the "sharper" or more harsh and forceful each exhuast pulse will be, and the higer it's individual frequency.

The type of aspiration is a factor, because in the case of orinary supercharging, the effective compression-ratio will be increased, and in the case of turbo-charging, or dual-stage turbo-supercharging, the exhaust, instead of exiting directly into the atmosphere, is routed through the turbo compressor and it's plumbing. This will not only mute the sound, but smooth it out and produce various resonant and musical whistling effects dependent on the length and diameter of the plumbing, and also the size and rpm of the turbo, along with the shape of air inlet and outlets.

So like each different style and type of musicla instument, the reason for any particular internal combustion engines distinct sound, is simply because it is a distinct mechanical device who's dimensions and construction and material is completely different from others.

My God I am good......

Jumo*******

blazer-glory
06-10-2006, 01:54 PM
Wow! Could'nt have asked for a more detailed answer. Thanks

GR142-Pipper
06-11-2006, 01:45 AM
Originally posted by Jumo*******:
The sound qualities of an internal combustion engine are dependent on the number of cylinders it has, it's rpm, compression ratio, type of aspiration(carbureted, fuel injected, supercharged or turbocharged, and it's rpm operating range.

The number of cylinders vs. the rpm operating range will determine the number of "pops" per second, or the "frequency" of the sound.
The higher the compression ratio, the "sharper" or more harsh and forceful each exhuast pulse will be, and the higer it's individual frequency.... Another issue is the prop type and the shape of its blades.

An example of that is the Huey H-1 with the "whop, whop, whop" sound. It's the result of the two-bladed rotor tips being near mach 1.

GR142-Pipper

IL2-chuter
06-11-2006, 02:13 AM
Ya, some planes have a very distinctive prop noise at speed . . . and don't forget the number of valves and valve timing . . . http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif


Always glad to chime in . . . http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

The-Pizza-Man
06-11-2006, 07:21 AM
Yeah, sleave valves made a very different sound compared to poppet valves.

stansdds
06-11-2006, 09:08 AM
Exhaust system can alter the sound as well, very short, individual stubs for each cylinder vs. long pipes or a collector ring connecting the cylinders to a common pipe.

ImpStarDuece
06-11-2006, 09:11 AM
The engine installation on each material individual aircraft type gave it a different engine nosie as well. The Merlin on a Hurriance sounded different from that on a Spitfire, which sounded different from that on a P-40K or P-51B/C/D.
Even before they saw it RAF pilots could easily tell the difference between a Hurricane and Spitfire, just from the engine note in flight.

I guess things like the engine mounting and bracketing to the airframe, type and shape of material surrounding the engine and exhaust type/shape also effected the particular sound that each engine made.

SkyChimp
06-11-2006, 09:17 AM
Originally posted by blazer-glory:
What is it exactly that gives the Merlin engine that distinctive sound?

Internal combustion. And a burrito.

slipBall
06-11-2006, 02:37 PM
Even the quality of the fuel used can affect engine sound

p1ngu666
06-11-2006, 04:33 PM
ive heard it was the cams, that give it its distinctive sound http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

griffon sounds nicer tho

WOLFMondo
06-12-2006, 05:01 AM
Originally posted by The-Pizza-Man:
Yeah, sleave valves made a very different sound compared to poppet valves.

The Napier Sabres on the Tempest and Typhoon had an extremely distinctive sound, due to the sleeve valves and 24 cylinders running between 3000 and 4000 RPM.

Its actually a horrible high pitch sound but very distinctive to that engine only.

danjama
06-12-2006, 05:08 AM
The Spitfire, P51 and P47's all have amazing sounds! I have to say, and i hate myself for it, that the P51 is beating the Spitfire sound-wise for me these days http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

That high pitched weezy sound gets me all gooey

luftluuver
06-12-2006, 05:23 AM
Originally posted by p1ngu666:
ive heard it was the cams, that give it its distinctive sound http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

griffon sounds nicer tho It is the whine of the supercharger gears. The Griffon had a different firing order than the Merlin and had more of a growl like the DB engines.

A Spit XVI and a P-51 fly over all the time. The only way I can tell which a/c it is if I see it.

Salfordian
06-12-2006, 05:43 AM
2 merlins flew over our house yesterday afternoon,

http://www.raf.mod.uk/equipment/merlin.html

http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

blazer-glory
06-12-2006, 12:15 PM
Originally posted by luftluuver:
A Spit XVI and a P-51 fly over all the time. The only way I can tell which a/c it is if I see it.
Really!? Where you based?

LOL Love your sig by the way! http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif