PZL Mielec M-15: One of the Aircraft of All Time

"Of all the aircraft ever designed the M-15 was certainly one of them"

I don't think anyone saw this video coming. Unlike the PZL M-15 which you could probably see coming from miles off due to it's embarrassingly slow top speed.

My new Bluesky account which I forgot to link onscreen:

3D Modelling by Artem Tatarchenko:

Sources available here:

Playlist of video sources:

00:00 Intro
04:00 History
07:05 Jet Engine. A terrible choice
15:54 The lala-1 test aircraft
19:40 Biplane. Hear me out...
22:52 How to ruin a biplane
31:28 The weird fuselage
37:57 The cursed varients
42:39 Performance
49:34 Legacy
52:22 Thank You

[Alexander-the-ok]

I’ve had a few comments claiming my explanation of propulsive efficiency is incorrect. Many of the ‘correct’ explanations are actually just synonymous with mine - I’m just explaining the end result rather than the mechanics of it (conservation of momentum, frame of reference, area drag etc). Try drawing a mass flow diagram from the perspective of a stationary observer if you’re in doubt.

Sorry if the explanation is unintuitive for you, I’m more than aware that I often conceptualise things a little differently to others - sometimes that is a benefit for making videos, sometimes it just confuses people.

8:00 I mixed up static gas turbine generators (like those on the oil rigs I mentioned) for aviation engines which have to actually output a thrust. Turbofans managed up to about 50% thermal efficiency in reality.

20:20 I don’t really explain roll stability well there. It’s more about airflow hitting the fuselage than where the COM is.

39:40 Thanks to @kikogitar25 for making me aware the M-15 is now at 50.3108911N 21.4614574E. Looks like it's been nicely repainted too!

43:45 Damgarten was in EAST Germany, not West Germany...which certainly changes things. Every time I try to say something good about this aircraft, it gets thrown right back at me.

A couple of other points:
The test pilot account is actually from 2005 so he wasn’t exactly giving it ‘under duress’. I absolutely believe it was a good aircraft to fly for him. For an agricultural pilot….maybe not so much.

Ok ok I was too assertive about the chemical weapons myth. The military did evaluate one but I very VERY much doubt it was designed for that from the start.

[I_am_sam_I_am]

"Jet-powered fixed undercarriage biplane cropduster" At no point in this sentence would I have been able to guess the next word

[absolutechaos]

A short story to add some credence to how durable crop dusters need to be:

My grandfather owned a small grass strip airport. One day him and my father watched as a crop duster took off, made a left-hand turn, and flew straight into the neighbors full, concrete, silo at considerable speed.

My dad and grandfather, fearing the worst, drove over to recover the pilot's body. When they got there, they saw the pilot sitting in the armored roll cage, wings, tail, and engine ripped off, staring straight ahead, death grip on the stick.

"Are you OK?"
"I think I pooped my pants."
"Well, if that is all, I think you got off lucky."

Also, congrats on 100k!

[caprica_]

Hey, pilot here! Placing the engine above CG actually is useful, and the planes where this is the case are a joy to fly. Airplanes pitch up when increasing speed, the pilot counteracts this first with elevator pressure then with pitch trim to trim out control forces. This is even worse in airplanes where the engines are below CG, like most under-wing airliners. I happen to fly a plane with engines mounted above CG, when we increase power the increased down force from the thrust counteracts the natural pitching up tendency of the airplane perfectly. So the plane just goes straight ahead but faster. Makes the plane a joy to fly! The plane I'm talking about is a Hawker 900XP, which is indeed a British design. I've also flown with wing mounted engines for years (King Air 350) and the pitch up tendency is definitely there. During stall recovery where you're meant to go max power, it can be so intense that you have to first give it some power, then trim nose down a bunch and then give it the rest of the power.

[antibrevity]

"The Soviets made the bi-plane bed, so they should have slept in it" is excellent writing, even if it will only be appreciated by a very particular audience. It's also not a sentence that's likely to have ever been used before in the History of mankind and may never be again. Thanks for the video.

[Blockio]

I was actually telling some people about this thing a couple of days ago, great time for a deep dive into it to be posted.
"once you're fitting thrust reversers onto your crop duster, it's probably time to take a step backwards and ask yourself what you want to achieve" was my definite highlight of the video; that got a good chuckle out of me.

[catcatcatcatcatcatcatcatcatca]

That triple cabinet version actually seems like an awesome experience for passengers.

Usually passengers don’t get to see straight forward, no matter how good the view elsewhere is. At least without sitting next to the pilot.

This design offers views better than the pilot gets, as the pilots side view is obstructed by these cabins. And that pilot is still getting the same view the crop-duster pilot had, which was excelent.

[trabienjoyer]

To the matter of "laminate" in 22:42, the word "laminat" in polish or "laminát" in czech generally refers to fibreglass/composite. So it may have been that the lower wings were partially composite.
Otherwise, stunning work as always :D

[Manulninja]

Never has a video about cropdusters filled me with more dread than getting past the 30 minute mark on this only to hear Alex say "Let's go through the cursed variants..."

[nuclearmedicineman]

Imagine being a passenger on that "special" variant, strapped into the wingpod of death, majestically soaring through the skies.

[MBkufel]

I love the Belphegor. Every time I visit the Kraków aviation museum, I pay this bastard of a plane a special visit.

[paweiwanczyk]

I've seen this plane in person, and as an aerospace engineer it is hilarious, but as a Pole I'm proud that our engineers made this abomination ;)

[altonschultheis]

As an aerospace engineer (at least by education) the I-beam-to-biplane-wing pipeline both delighted and horrified me… and I’m sorry for the lack of concrete in the design

Also, man I’d just love the look of this cursed little guy with a pusher prop

Edit, dear lord the proposed variant with the turboprop… I specifically requested the opposite of this

[szymon]

Great vid! My grandfather was a mechanic working on M-15 in Mielec. At that time, Poland was part of the Soviet bloc, and tovarich from Moscow decided that Poland would work enthusiastically on this design, because heaven forbid, they could work on something of their own, and that wouldn't be nice. You're top lad, cheers from Poland!

[tomaszkarwik]

22:34 wood laminate would be "sklejka", if the original used the word "laminat" that implies composites.
Source: I am Polish

[jingojango]

Alexander, you and your videos are far more than just ok

[ZeteticPhilosopher]

Wow. I just realized you only have 100k subscribers. You might be the best engineering channel on youtube.

[jk-mmto]

My uncle worked at that factory during the 1970's. I recall the time they sent a van with 3 men to drag him out of bed because he was too hungover to go to work.

[OutbackCatgirl]

This goofball looks like something out of my early KSP addiction, back when the atmosphere was made of soup and the infiniglide glitch could send winglets to space

[tomcarlson]

"I'm almost sad that we never got to see this piece childhood artwork fly" That's one of the best quotes for the video.