I always think the p39 is fascinating plane due to the amount of myths surrounding it and the differences in reputation between the Soviets and Americans. It really shows how much the use of an aircraft can change its performance. I would love another video about the p39.

As a kid, I was gifted an encyclopedia about airplanes. The P-39 was one of the aircraft that always stood out.
Special place in my heart.

My late father would have thoroughly enjoyed this excellent presentation.  He was a P-39 pilot.   He also flew P-38’s.

I just love how the Airacobra looks. Such a beautiful machine.
I'd really like to hear more about her.

It also has to be remembered that it was P-39s along with F4Fs that initially held back the air assaults by the Japanese on Guadalcanal. Good pilot training probably also contributed to their success, but if the planes were crappy I doubt they would have lasted as long as they did.

It was so shapely and sexy. The exhaust stacks jutting out mid ship is pure hot rod

I love this channel.  I built all these as model kits back in the 1950s and each kit had its own fascination.  Now, in my mid 70s, Greg's in-depth treatise on the various WW2 warbirds is a great way to revisit them.  These videos should carry college credit.

Great job! Thank you, Greg.
The first unit in Soviet Air Force to fly Aircobras was 298 Fighter regiment. That were P-39K and P-39D-2. The regiment's planes (mostly I-16)  were completely destroyed in the early months of the war. On October 20, 1942 pilots of the regiment arrived at Adjikabul (Azerbaidjan) to study P-39 got via Iran.

The study began from learning the construction of non-flying P-39D-2. On January 5, 1943 first three P-39D-2 arrived and on January 10 the flights began. The were no accidents during the study.

By January 26 the regiment got all the planes. It was February 3, 1943 when the regiment left for the war front. It had 32 planes: 3 squadrons with 10 planes each, plus 2 planes in HQ. 11 – P-39K (37mm cannon) these planes took heads of regiment, squadrons, etc; 21 – P-39D-2 (20 mm cannon) – for ordinary pilots. Some sources say there were 33 planes (11+22).

By February 16 the regiment arrived at Kuban and became a part of 219 Bombing division. Its main purpose was escorting A-20 “Bostons” of 244 and 277 Bombing regiments. The regiment flew for hunting as well and by early March 1943 shot 5 Ju-52.

In March the regiment made 417 operational flights (567 flying hours), shot 24 planes (10 – Me-109, 2 – FW-189, 1 – Ju-88, 5 – Ju-52) in air and 5 Ju-52 on the ground. Lost 9 planes (7 in combat, 2-non combat loss), 4 pilots killed.

During April 1943 the regiment made 346 operational flights (430 hours), shot 50 planes (40 – Me-109). Lost 4 planes, 1 – MIA, 6 planes damaged, 1 – lost during transfer flight. The unit got new planes: 11 – P-39L, 2 – P39D-2. Quote from that time report: “Air fights analysis shows, that Aircobra is equal to Me-109 in horizontal and vertical maneuver. Turning radius is smaller, height gain in combat turn is bigger.”

In May the regiment made 514 operational flights, including: 14 – bombing escort, 54 – covering of troops, 2 – “clearing” the air before attack, 5 – against bombing raids, 2 – reconnaissance. Conducted 39 air fights, shot 40 fighters and 27 bombers. Lost 6 planes (5 – shot, 1 – MIA), 2 pilots killed.

On May 24, 1943 two pilots of the regiment got the highest military award (Hero of the Soviet Union): Vladimir Seminishin – 8 personal and 7 in-group shots, Vasily Drigin – 12 personal and 5 in-group shots.

End of part 1.

There was some wieght savings built in to the mid engine design.  Mainly that the engine sat on webbing directly attached to the wing spars, eliminating the typical steel cantilever engine mounting frame.
The "Aleutian Zero" was tested against the P39. The 39 could out run, out accelerate, out climb, and even to an extent out turn the Zero at LOW ALTITUDE.  However, the power loss was so severe with increasing altitude the the 39 became unstable at only 12,000 feet.

Greg, great video as always.  I spent over 3,000 hours in modern Navy Fighter Jets / Training Jets and would agree with your comment about G-Loading.  Modern Jet cockpits are well in front of CG, and allow pilots to pull upwards of 7 to 9 G's (depending upon the aircraft).  G onset is a concern, but given modern training and assistance from G-suits, it is easily combated.  Sustained G is generally the more challenging of the two...G-suits / training help, but one's physical fitness is more important.  Our Demonstration teams don't use G-suits while flying the Blue Angels and Thunderbirds, relying purely on technique and physical fitness...the more important of the two components of fighting G.  

Bottom Line:  I don't think the Mid-Engine design near the CG for the P-39 made a huge difference in that era for G-Onset for the crews. However, it probably made it feel more lighter and responsive on the controls....but I've never flown it nor read any books on pilots who have.

Non combat accidents in the Army Air Force were significant, almost half of all losses. My dad survived the collision B 17 with a B24 training over Lavenham England in ‘44. Out of 21 crew 11 lived. The aircraft were of course destroyed. In the fourties’ flying was much more dangerous than today, even when you weren’t being shot at!

As a racing fan I always loved the look of the P-39 since it reminded me of a formula one car with its airbox behind the pilot’s head.

I always loved the Airacobra's clean lines.

15:05, it was called the 'Townend Ring' not the TownSend Ring, it was named after its inventor, Dr Hubert Townend of the British National Physical Laboratory. Also, the spelling of the aerobatic manoeuvre is 'Lomcovák', often anglicised to Lomcovak and sometimes incorrectly spelled 'Lomcevak'. It was a term coined by the mechanic of famous Czech aerobatic pilot,  Ladislav Bezák.

Thank you, Greg, for doing a more in-depth dive into the P-39 design, it's strengths and weaknesses.  As a career aero engineer, I have been standing on the sidelines watching so many poorly thought out comments and criticizms of the design and hoping that someone would step forward with a well researched and comprehensive article.

In the trade, we often hear the term, "synergy".  The P-39 to me is a clever example of synergistic thinking, where one change results in many benefits.  The P-39 is a really clever combination of features that resulted in a compact, lightweight, powerful machine.  Unfortunately, it also resulted in a design that had very little internal volume for fuel or for turbocharger plumbing or cooling.

The lack of space for a turbocharger was quickly recognized and that feature deleted.  Unfortunately, that change made the airplane into a low altitude fighter only.

The lack of internal volume for fuel was a tougher nut to crack.  The very cleverness of the design packaged other necessary components too close together and certainly consumed most of the space near the center of gravity.  In the end, the low fuel capacity limited the range and  lack of a high altitude engine limited the operational altitude.  So you wound up with an airplane with a narrow operating envelope.

Regarding the stall/spin characteristics, I don't have much to offer.  Early in my working career I rubbed shoulders with many WWII vets who had flown P-39's.  Most of those with whom I discussed the airplane viewed it as a fun and feisty little machine that was entirely useless in a combat role.  A great little sport flyer.

The shaft drive experience must have been useful for Bell's subsequent helicopter building career.

If anyone is watching this video who hasn't read Bob Hoover's autobiography you're really missing out.

Great video explaining an often misunderstood aircraft. Thanks Greg!

What I like best about your videos are the research and references to original sources and documents, and of course your analyses. So many others will just rehash the commonly already known knowledge and myths…. but with your work we can be sure we are getting the facts…. great work…!

What a beautiful plane that captures the "Streamline Moderne" style of the 1930s.

Hi Greg,

LOVED this presentation on the P-39. I've had a sentimental place in my heart for the P-39 since I was a kid. It came from the Doubleday War Planes books (5 inch x 5.25 inch size) of the early 1960's, the "Fighters 4" edition. What was the first plane discussed? The P-39! That little book sparked my imagination about WWII fighter planes, a love I have to this day. I even fly an RC version of the P-39 (1.2 meter wingspan) and it flies excellent! I hope you do another P-39 presentation. I always thought that the P-39 was just caught in an "in-between" moment in aviation development and could have been quite an excellent plane. I still love the looks of it.

Thanks for all your work in bringing these WWII planes to life with their development stories. Fascinating stuff. I've loved the P-38 and P-47 articles in particular. They are also favorite planes of mine.

Best of luck to you and your channel!