Why was the P-51 Mustang so fast?

[richardryan]

Laminar flow wings, shaved rivets, flush rivets, cool paint job. Go fast!!

[adammccarthy]

The Meredith effect is a phenomenon whereby the aerodynamic drag produced by a cooling radiator may be offset by careful design of the cooling duct such that useful thrust is produced by the expansion of the hot air in the duct.

[davidbeattie]

They didn't take off the rivets. You can clearly see them. North American used flush rivets instead of conventional rivets with a domed head.

[jolla]

My father as a teenager polished the rivets on many a Mustang, that was his job during WW2, and one he loved.

[kzfittycent]

I had no idea the radiator configuration did that! That’s so cool!!

[RayHaffenden]

aerodynamics and most of all the RR engine!

[releasethekraken]

So in laymans terms, because of the radiator the Mustang has jet propulsion without a jet

[tomriley]

Supermarine used flush rivets on the Spitfire too, in 1940 producing them for the Battle of Britain they realised that not doing flush rivets fro the ones in line with the airflow had minimal effect on speed so stopped doing it on those.

[paulprice]

When I was a child, i would always draw the mustang & mosquito. My top two, most beautiful aircraft... ever.
Such an iconic plane

[Byepolarchaos]

My father-in-law flew a mustang in both theaters and said it was the scariest weapons he was ever given to kill the enemy. He almost felt privileged to the extent that it wasn’t a real battle when he came upon the enemy, the speed maneuverability its ability to fly thousands of miles, and of course the fire power towards the end they actually have a couple of mustangs that had 20 caliber guns on the cannons I should say, and the glass was truly bulletproof. Do you wanna come home with the plane? He might have several hundred holes in it. They literally would patch it up. Take it for a test flight. He be back up in the air and five hours. He always wanted to guys on the ground to get more credit, he always said the credit they want is watching the guys they repaired planes for to come home land, and be safe very very special time for the greatest generation that has ever walked on this planet.

[ChrisRidgway-eg]

As a aerospace sheet metal worker making details and sub assy for major manufacturers you leave the counter sink rivet slightly proud and use a rivet mill to make the head flush with the skin.

[carlosspiceyweiner]

My great uncle flew them for a year, the only bad thing he ever said about it was the cockpit heater sucked. I guess it would cook some places and let others freeze.

[Besieiro]

i didn't know about the radiator propulsion, awesome

[Rammstein]

Very interesting to see the details of these airplanes, things I normally wouldnever ever know👍

[jeffreyhansen]

This is the first I have ever heard any mention of the engineering that is involved in the ducting of airflow. Been aware of the effect for decades and it is much more involved then the brief mention here.

[izhmlps]

They didn't take off the rivets. They used Flush Rivets in countersunk holes.

[spingebill]

Laminar flow wings was probably the main reason the P-51 was so fast for its propulsion.

[kensmith]

The down side of the radiator was that if a pilot had to belly flop the plane, the radiator would dig into the ground and flip the plane

[miaohmya]

Very neat I've just read all about the Meredith effect (which I didnt know). The radiator creates drag, but the design of the exit nozzle makes thrust that offsets the drag. Very cool! 😊

[edwardcnnell]

While it used the same engine as the Spitfires and Hurricanes, it got greater horsepower. The US sent 150 octane fuel with the British used about 100 octane so the boost for the supercharger could be set higher. Later in the war the US was able to send the higher octane fuel to the British.