The Secret Behind German Engine Performance: GM-1 and MW-50

hello everyone it's chris from military aviation history and today i want to address something i get asked about a lot that being of course german world war ii aircraft engines you know take your diamondband 601 605 to umu 213s the bmw 801s and so on plus of course the use of those two special substances gm1 and mw50 to boost the performance of these aforementioned engines and i think those are some really excellent questions because engine technology is at the heart of aircraft design performance and capabilities and actually we don't talk about it enough even though if we talk about aircraft we really need to start talking about engines before anything else but that topic in itself can be broken into a few sub-chapters what interests me for example in aircraft engine well those are for example the strategic and the operational aspects of engine production the logistics involved the operational performance and of course the associated developments throughout the years but beyond that there are of course the nuts and bolts sort of engineering aspects and i think i know someone who is a lot more qualified than me to talk about those so instead of me answering this question of what gm1 and mw50 is what it does in your german aero engine and why it was used i thought i'd invite column douglas who is an engineer and he is also the author of this book the secret horsepower race western front fighter engine development this is a book that came out recently actually only a few weeks ago and i ordered this book back in april as a pre-order and i've been in touch with callum douglas for some time so i thought you know what i passed this question on to him and he sent me back a really really good answer in video format with plenty of insights that i think a lot of you will enjoy so enough from me over to calum douglas hi my name is callum douglas uh author of this rather weighty tome the sacred horsepower race which is about world war ii engine development and um chris from military aviation history has asked me to do a short video talking about gm1 and mw50 which is nitrous oxide and methanol water injection so we're not going to cover all the operational aspects it's really just to give you a bit of a feel for what they actually were how it was used and why it was used going back to the original documents and avoiding the typical wikipedia type mistakes on this stuff so let's get started so the first thing we'll look at is gm1 um which stands for guri mitchell heights um which is guring's mixture number one um which is just because uh when it was developed it was developed at the goring institute and basically the um guys there decided that it would be a good career move to make sure that they mentioned the boss so i don't think goring had anything to do with this so why might we want to use nitrous oxide well a big problem we've got with airplanes is that they have to go quite high up in the air so that's uh i've scaled it approximately but that is basically um the height of mount everest and when we're down at sea level we've got one bar of atmospheric pressure so this is very happy situation for our aero engine because we get lots of air into the engine and make lots of power as you want to fly higher and higher up the air pressure goes down and down and down quite dramatically and so if you want to fly really high something like that's obviously the sr-71 you can see when we get up to 25 kilometers the air pressure there is something like 20 times less than it is at sea level so and this is a little cessna here flying at five kilometers so some people do get a bit surprised when we look at how far up world war ii aircraft can fly i've put in a plr spitfire but also some ta152 variants would also reach the same altitude so it's about 15 kilometers and if we look at this graph basically we've got something like six to eight times less pressure at this altitude than you've got at sea level so this is a big problem because if you've got less pressure we've got less density which means that the amount of air being sucked in there's less oxygen in it and we can't burn the fuel without oxygen so if you're flying up here you've got a big two-stage supercharger which is basically two hair dryers connected in series and this does a reasonable job of stuffing the air into a smaller volume so that we've got more oxygen in the cylinder but we can do more and the first person to really apply this to an aeroplane engine was dr otto lutz at technical university braunschweig in the late 1930s and he published a lot of his research in this very prestigious german academic journal in the war the deutsche academy for luftwaffe which is just a sort of german academy for aeronautical research and sciences and basically what he came up with is using nitrous oxide to boost engine performance so what it actually doing well there's two things it's doing to make the power go up at the start so basically the first thing that happens is that it evaporates um because it's stored at a usually at a low temperature so when that evaporates it cools down the air into the engine which makes it denser basically when it's inside the engine the nitrogen and the oxygen separate which is an exothermic reaction which just means it produces heat and these two things disassociate so they split apart in combustion so an engine is a heat engine so if you more heat into the combustion cylinder you get more power essentially and the second way it creates more power is that the oxygen content of nitrous oxide is 36.4 percent by weight instead of 23 of air so this means we can burn more fuel so these are the two mechanisms by which the nitrous oxide is actually producing more engine power so we do obviously to take advantage of this actually have to also inject more fuel when the nitrous oxide is going in to get the full effect so the first time this was actually used operationally is really towards the end of what would be called the battle of britain 1940 i don't have exact dates but if we look at the german aim industry meeting minute abbreviations uh not abbreviations the minutes the abbreviated minutes we can see here that the first code word for nitrous oxide actually wasn't gm1 in the very early days it was called mona um i don't know why maybe someone does and basically what they're saying here is that the installation of mona nitrous oxide is only for three staffers for those of mulders galand and wick and as most of you probably know these were three of germany's most famous aces at the time so it's quite interesting to note that this stuff is really being given to just a very small number of aircraft in these very elite units so it wasn't a fair fight by any means they also produced a promotional video at the hermann goring institute to show everyone what they'd been spending all the money on and this is uh message 109 e which has been filled with gm1 so that if you look there that's the actual middle filling cap that has to be removed and the tanks are just in the fuselage behind there and there's a chase playing with a camera which probably a messerschmitt 110 and there are two me109s here you can see and the one i've circled in red the pilot is basically just going to unscrew a valve in the cockpit which is going to allow the nitrous oxide in and it basically vanishes off into the distance so make quite a big difference so along the bottom here we've got the speed of the aircraft and here we've got the aircraft altitude in kilometers owner and mit means without and with so for example at eight kilometers without gm one we are doing in a messerschmitt 199e about say 545 kilometers per hour if we turn it on we're doing 600 so basically we've gone plus 50 kilometers per hour and that advantage increases as we go up because the oxygen content of the outside air is going down and down and down as we go up so this is the advantage of it i i think this is probably um a fairly extreme example i suspect that there may be putting in more gm1 here than was done operationally because as you see at 11 kilometers the speed advantage is really about it's about 150 kilometers per hour which is is really a lot and i think that might be with um a very large dose of gm1 which may have been more than was used operationally um now looking at where this stuff was actually made is quite interesting so this is just a little graph from one of the german wartime reports and it's all pretty secret and i don't know what h0v and m mean here maybe someone can can tell us i suspect they're code letters but i might be missing something but basically if we look at the little little key here um the circles are where the stuff's been made the square is where it's being stored and the diamond shape is basically um where everything's gathered at the front um for the the aircraft and the two lines here first one the solid ones that's the lower one so that's nitrous oxide stored at low temperature to make it a liquid and the dotted line is nitrous oxide stored as a liquid by being stored at high pressure so there are two ways you can make it a liquid you need to either cool it below its liquid point or you need to pressurize it and so there seemed to be there were two different systems in use at that time and this is just a little translated paragraph for you from the original report so they're just saying that it's pretty good for availability 60 tons a day from two places in germany and in occupied france so i've overlaid this map with google maps and it's only very approximate but i think the two sites in germany appear to be frankfurt and spire and in france leo ruin i don't know how to pronounce these leviers and tonight i'm sorry if i'm pronouncing that wrong but i think that's approximately where these factories were i would imagine today you might find these towns have still got some sort of industrial area nearby and maybe some natives of france can give me some tips on these because i haven't tried to visit these sites so one of the first measuresmiths that were captured in england with the gm1 system crashed in dorset on the 9th of june 1941 and this system had gm1 kept as a liquid under pressure what this basically means is that um the tanks that store it have to be really thick because there's high pressure inside and they'll burst if they're not very thick so the tanks are quite heavy and also if they're hit by bullets which is quite likely if you're a messerschmitt pilot or any fighter pilot in the war um they don't react very well so there are plus and minus points to storing it under pressure or as a liquid the early systems used by the luftwaffe all stored it under pressure and later on they moved to storing it at low temperature but just in atmospheric pressure so literally just sort of pouring in out the bucket almost if you like into the tanks which were insulated um so we've got three tanks here and the pilot has this control in the cockpit and there's a pressure gauge and he turns this on and the gm1 flows through into the engine and the uh the engine also needs uh some fuel enrichment to take advantage of that um it's quite a funny story here because british air intelligence is normally pretty good in world war ii um they had some very well qualified people but they really dropped the ball with nitrous oxide it's it's quite embarrassing to be a brit if you read the papers on this so the german pilots were sworn to secrecy and in fact they weren't told what the system was so the german pilots unless they were very well connected and word got through to them they didn't know it was nitrous oxide so they were given a key word to tell um the british when they were captured which obviously happened and earhart milsh said that um under no circumstances did he want the british finding out what this was so basically they were told to call it the haha process which is an incredibly bad code name because nitrous oxides also known as laughing gas it's um it was used as an aesthetic as well so it's a really shockingly bad code name they still didn't get it it took them really a good couple of years before the british realized it was nitrous oxide when things crashed the tanks would always be ruptured and so they wouldn't really be able to find out what the contents were so it's quite funny reading this transcript actually um so this is a bit later on in the war so this is 30th of may 1943 so juncker's ju-88 which had nitrous oxide system and um the pilot incidentally simon siegfried if you're interested and that's the break number of the aircraft and this is an raf technical officer and he's found a tank here which is not actually the nitrous oxide tank so because it is a heavy compressed bottle and by this point they were using it stored under low temperature as a liquid in a thin tank it's very lightweight and it's less susceptible to rupturing if it's hit and you get more engine power because you're storing it at low temperature so it cools the intake charge more when it flows into the engine but it has other difficulties what he's found here is that it's one of the compressed air bottles that were used to push the gm1 out of the tank because if you're not storing it under pressure you have to encourage it to go into the engine so the ju-88 system had compressed air bottles and these forced the gm1 out the tanks threw into the engine so that's what he's found and he knows it's a bit special because it's got no markings on it and normally the oxygen cylinders would always have the markings on so the ground crew in germany or in any country know what the bottles are to refill them so they don't refill it with something that they shouldn't so he knows it's a bit special because he's got no markings on it and if we look at the gm1 system that's installed in the ta152h you can see the same thing so these bottles here these are the compressed air bottles used to force the gm1 out of the tank and this is the main gm1 tank here called number two and the nitrous oxide is stored in here at low temperature uh not under pressure and the kind of results you can get so this is just looking at the bmw 801 so this would have been some of the later fw 190 models and basically these are the power curves so the solid line is owner gm1 without dotted line mid width and basically it's only used at high altitude um principally because it's an oxygen carrier so although it raises engine power the best advantage is to use at high altitude when you've got very little oxygen the atmosphere outside you can use it at sea level to boost the engine but if you read my book you'll understand that germany had a lot of problems with aero engines at the time and they couldn't really boost the power at sea level too much without damaging some of the engine components so this is why it was really strictly only used at high altitude although it could be used in theory at sea level so if we look at the dotted line here we've got something like eight kilometers if you engage the system we've gone from 900 ps to 1200 ps so it's basically um 300 horsepower so it's a it's pretty decent advantage it's it's it's very very useful amount of power um for the fw 190 it's supposed to have only been used at the a8 which comes in 1944 but i've actually got wolf drawings for gm1 tanks which are dated 1942 so i'm not completely sure what happened there if there was just a big delay with the tank manufacturer or if the use started maybe informally quite a bit before 1944 so i'm not quite sure about that further research is required let's have a quick look at mw50 it's methanol water the 50 is because it's 50 50 water methanol you don't have to have that that's just the usual ratio that was used by the luftwaffe and so basically to to raise the power it's basically the latent heat of evaporation basically just means the stuff's a liquid if it becomes a gas when you inject it it changes the phase and when you have a phase change in a liquid it needs a big amount of energy to change it from one phase a liquid to a gas phase so it absorbs a lot of energy to do that and it's about two kilojoules per kilogram of the stuff you're putting in i can't give you a temperature drop from that because it depends on what the flow rate of what you're putting into is to work out how much the temperature would be dropped but it's it's a lot and in fact according to my research at least in aero engines for fighters it was first proposed by two bmw engineers actually single man and zabowski and first tested on a brahmo engine and you can read more about that in air 40 at queue national archives and so if you look at the system in a 109 um basically you've got a tank that sits with methanol and water in it behind the pilot you've got the supercharger and the pilot has two different switches one to energize the system and one on the throttle lever to make the methanol go in and these parts actually look like this so thanks to chris starr for showing me these bits so these are original um measures met 109g mw50 components so you first energize the system this switches on the cockpit uh front panel iron so it's on and then this switch here is on the control stick and you press it and that activates the system uh the methanol flows through this valve here and through a filter and then it goes into the pressure gauge so that would be sitting in the cockpit of the 109g facing the pilot obviously so that's basically how it works in terms of bf109 types using it if you look at the db605 engine designations uh the introduction of m tells you that it's got methanol water injection am asm etcetera this is approximately from the g6 onwards and the k which very limited production of so it gives you a really big boost in power at sea level and basically in this example here you're looking at about 300 horsepower so it's a similar advantage to the the nitrous oxide it's dependent on the flow rate but the balance you've got in an airplane is weight is a huge issue so there's a balance between how much power you can get and how long you have it for so they worked out a kind of best case scenario of how much power is useful and how if over what period of time so they just worked out that 300 horsepower is a good bet to have because you could have it in the plane for a reasonable amount of time without it running out or being too heavy that you can't take off so about 10 minutes so we can use both systems at once and so if we look at the ta-152h so we've got a gm1 tank here and we've got fuel tanks and there we can see mw50 bear helter so that's a tank 70 liter mw50 tank and there's a bit of debate about how much we're in the tanks it seems to change quite a lot between the different models um this is a slightly simplified paragraph that's in some of the british files on the system it's i think pretty similar to a umo 213eb so but for the purposes of explaining it it's pretty close so basically that's the normal power of the engine if you just put the methanol water in you get about 100 horsepower and that's not with putting the boost up that's just because the methanol has some fuel calorific value so it increases the power a little bit and if you then once you've got that also put the boost up and you've got more main fuel going in to put the boost up and more power you can see we're going from 1850 to about 2250 horsepower for this particular engine it depends on which variant and you can see with the gm1 they did eventually get to having a couple of different flow rate settings so the maximum was about 300 horsepower and this is a graph covered up by my ugly face here of bmw 801e so just so you can see it's the same kind of system here so you can see the approximate change there yep so that's 2250 or so so just to clarify about the tier 152 this is quite a nice graph and it just shows you which of all the different variants were actually fitted with gm1 and mw50 because it's not all of them so you can see it's basically only the h1 and h2 so all the other ones didn't have both systems and as far as i can tell it does look like uh d2 152 did have 85 liters of gm1 and 70 liters in the wing of mw 50. so i hope you've enjoyed that short presentation we can talk about lots more details and um thanks very much to chris for inviting me to talk to you about this stuff and i hope you enjoy the video bye for now big thank you to column douglas for taking his time to give you and me a great little introduction into gm1 and mw50 i hope you enjoyed it and perhaps learned something from it as well if you enjoyed this sort of segment with a guest speaker please feel free to let me down in the description sorry in the comment section actually i might do some more of those and if you have any thoughts and feedback on this episode please leave them there as well and if you're interested in the book it is available now as i said i bought my own copy back in april this is not a review copy or anything and i'm reading through it myself at this moment as you can see there are two links to the book in the description below one is to the publisher website one is to amazon you will see a price difference between those however if you buy it via the publisher the offer will get a better cut it is of course entirely up to you whether you buy the book or where you buy the book but i thought i mentioned that just in case you're confused about that difference there in any case once again thank you very much to callum douglas for his uh for sending in his video segment and uh thank you also to you for watching this video and if you are enjoying these sort of videos please consider supporting via patreon or channel memberships because that supports this channel and for example it also allows me to buy books like this one and all of the other ones as sources for upcoming videos if you enjoyed the show please also consider supporting by sharing this video and as always have a great day and see you in the sky

Channel: Military Aviation History

Views: 91,379

Rating: 4.9529514 out of 5

Keywords:

Id: stL8eSyieSU

Length: 28min 19sec (1699 seconds)

Published: Thu Jan 28 2021