Water Methanol Injection Explained In Detail

[MiloMorai]

In the end, the various U.S. Air Forces set their limits somewhere between Kelsey and Wright Field. Actually, it was the fighter pilots and their crew chiefs that often had the last word on how the powerplant controls were rigged, and it was not uncommon practice to remove the throttle stops on operational P-38s. This provided full throttle (60-70" of manifold pressure) at lower altitudes, but it greatly increased the chance of blowing the engine. Many pilots thought that since they were the ones risking their lives on the cutting edge, it was only fair that they should decide how to use the power. The author has a friend who flew the P-38H, J and L models with the 55th Fighter Group, Eighth Air Force. He told me that he had the throttle stops taken off all three aircraft and, when necessary, used full throttle in combat. He had no problems with the H model overheating.

 

Oh dear, unauthorized modification of an engine.

[Sternjaeger]

exactly, it's not all about manuals...

[Crump]

 

Oh dear, unauthorized modification of an engine.

 

You think the head of the technical section of the 8th USAAF is doing something illegal and unauthorized?  No......

[Crump]

 

The XP-38 made its first flight on 27January 1939, with Lt. Ben Kelsey at the controls. Only five more test flights were carried out in the local area around March Field, California, and then the story takes an unusual twist.

 

 

On the other hand, Ben Kelsey (now a Colonel) and Colonel Cass Hough, of the Eighth Air Force Technical Section

 

 

You think these two did anything without both Lockheed and Allision being in the loop??

 

Convention says they did not do anything without Lockheed and Allison being in the loop. 

 

Kelsey was Lockheed's test pilot and both worked in the 8th AF Technical Section.  Not some fighter squadron or operational unit; an Air Force level technical section.  About as high up in star fleet command as one can rise.  Guess it makes no sense whatsoever that they picked up the phone and tapped into those resources as was not only the wise thing to do when it comes to modifying aircraft but the thing that is directed by United States Army Air Force and the Aviation Authority of the United States. 

 

But I am sure in some fantasy world they did not do any of that no matter how much sense it makes or the fact it was what is normal in aviation, they just winged it and flew hell bent for leather in their fighter squadron shooting down Jerry in droves.  No that is not sarcasm.

Edited November 6, 2013 by Crump

[DD_bongodriver]

In the end, the various U.S. Air Forces set their limits somewhere between Kelsey and Wright Field. Actually, it was the fighter pilots and their crew chiefs that often had the last word on how the powerplant controls were rigged, and it was not uncommon practice to remove the throttle stops on operational P-38s. This provided full throttle (60-70" of manifold pressure) at lower altitudes, but it greatly increased the chance of blowing the engine. Many pilots thought that since they were the ones risking their lives on the cutting edge, it was only fair that they should decide how to use the power. The author has a friend who flew the P-38H, J and L models with the 55th Fighter Group, Eighth Air Force. He told me that he had the throttle stops taken off all three aircraft and, when necessary, used full throttle in combat. He had no problems with the H model overheating.

 

 

Just thought I'd highlight the bits that got missed.

[Crump]

exactly, it's not all about manuals...

 

 

Sternjager,

 

It is about the manual.  There is no safety margin to speak of in aviation.  The physics of flight do not allow it.   What is printed in the manual is the latest information and the best possible performance you can get from the aircraft without having it kill you.

 

Lots of pilots think they know better.  They end up as statistics.  The NTSB says deviation from the published operating procedures is a factor 85% of the time in aviation accidents.  Think about that for a second.  If you deviate from the published operating limitations, 85% it contributes to an accident.

 

The reasons I just gave you is also why the Operating Limitations of the aircraft handbook carry the weight of law by convention.  It has been this way since 1919.  Unless you are specifically authorized to deviate under specific conditions, a pilot can and will be held responsible for not adhering to those limitations.

 

Now, in an emergency, a pilot can deviate from any regulation in order to do whatever he needs for the safe conduct of the flight.  If pilot is requested then he must submit written explanation for the deviation to the Aviation Authority.  That is if he is a private pilot on a joyride.  If he is a working pilot, including a Government aircraft, HE WILL submit written explanation for deviation.  He does not have a choice and the Aviation authority does not have to make a special request. 

 

Just thought I'd highlight the bits that got missed.

 

 

Yeah,  I don't think that is anything coming from the USAAF at all.  That part seems to be the authors input. 

[Sternjaeger]

Crump, I don't know how to say this, but you're applying a engineer-minded, modern, small GA mentality to a WW2 scenario. It simply didn't work like you think it did. They had manuals, then they had reality, and often manuals were disregarded, simply because in a military environment it's the ranking that decides, not the manual. If the pilot said to the ground crew "take the safety wire off", they had to do it, if every time he went out for a sortie he used WEP, they had to do their job and ensure the engine was fine. These chaps worked around the clock to keep their aircraft airworthy, and often tried to do their best to make the aircraft better. 

[JtD]

If everything went by the manual, the AVG (Flying Tigers) probably wouldn't have gotten airborne even once...but maybe before this topic gets hijacked by that silly debate, the mods could open up a special subforum where they can move all the off-topic stuff to that appears again and again and again and again and again...

ADI or even use of WEP as such is an interesting enough topic, imho.

[MiloMorai]

You think the head of the technical section of the 8th USAAF is doing something illegal and unauthorized?  No......

 

"it was the fighter pilots and their crew chiefs that often had the last word on how the powerplant controls were rigged, and it was not uncommon practice to remove the throttle stops on operational P-38s."

 

Since when are pilots and crew chiefs, the head of the technical section of the 8th AF?

 

Such unauthorized changes were not allowed in Germany since the changes had to come from the RLM and/or the manufacture according to an aviation expert.

[Talisman]

National Archive doc file too big to get through on this post, but for interest regarding Merlin engine life at emergency boost cut-out: 

 

Air Ministry, Engine Executive Committee, 3rd April 1940 minutes (Secret) of the fifth meeting, paragraph 125 (iii), engine data asked for at last meeting.

 

Minutes state manufacturer tested engine life of 10 hours continuous running, 100 Octane fuel, with boost cut-out 12 lb boost, but much longer for intermitent running.

[Crump]

 

Actually, it was the fighter pilots and their crew chiefs that often had the last word on how the powerplant controls were rigged, and it was not uncommon practice to remove the throttle stops on operational P-38s. This provided full throttle (60-70" of manifold pressure) at lower altitudes, but it greatly increased the chance of blowing the engine. Many pilots thought that since they were the ones risking their lives on the cutting edge, it was only fair that they should decide how to use the power. The author has a friend who flew the P-38H, J and L models with the 55th Fighter Group, Eighth Air Force. He told me that he had the throttle stops taken off all three aircraft and, when necessary, used full throttle in combat. He had no problems with the H model overheating.

 

 

Lots of pilot did this stuff btw, on all sides back then.   These guys were not the aeronautical engineers and technical pilots flying today so you do see some of this "I know better attitude".

 

We only get to hear about the ones who were successful at it!

 

Here is Focke Wulf pilots doing it.  They are using 1.8 ata by modifying the Ladedruckregular of the KG.

 

Of course the penalty for altering state property in Nazi Germany was pretty harsh and it was not looked up favorably.  It gets covered up to protect folks from a firing squad.

 

 

 

The result was a high instance of cracked cylinders.

 

Here is what the USAAF really says about following the Operating Limitations as published:

 

 

 

MANDATORY

 

Once again, it carries the weight of law.

 

Using the NTSB statistics....

 

So while we have rare and unauthorized accounts of the 15% who where successful, we don't have much from the 85% who were not.  The USAAF does not say, "do whatever you want" but follows the aviation convention the United States signed by saying it is mandatory to adhere to the published limitations.

 

 

 

"it was the fighter pilots and their crew chiefs that often had the last word on how the powerplant controls were rigged

 

 

What happens is the engineers and technical section LISTEN to the pilots and crew chiefs.  They do their level best to give them what they want. 

 

It does not mean that pilots and crew chiefs had the authority to do what ever they wanted regarding the operating limitations. 

 

[DD_bongodriver]

It does not mean that pilots and crew chiefs had the authority to do what ever they wanted regarding the operating limitations. 

 

 

Bingo!!! ......seems like an appropriate response.

 

it also doesn't mean that operating limitations were strictly adhered to by line pilots and engineers.

[MiloMorai]

Lots of pilot did this stuff btw, on all sides back then.  

 

So the outer wing guns of the late model Fw190As were removed.

[thx1138]

Crump, I don't know how to say this, but you're applying a engineer-minded, modern, small GA mentality to a WW2 scenario. It simply didn't work like you think it did. They had manuals, then they had reality, and often manuals were disregarded, simply because in a military environment it's the ranking that decides, not the manual. If the pilot said to the ground crew "take the safety wire off", they had to do it, if every time he went out for a sortie he used WEP, they had to do their job and ensure the engine was fine. These chaps worked around the clock to keep their aircraft airworthy, and often tried to do their best to make the aircraft better. 

 

In the world where people are shooting at YOU, the manual all of s sudden merely becomes a guide. ANYTHING that can help put the odds in your favor you WILL do !

 

Ask any combat vet crump, just ask them please.

[Crump]

What part of Mandatory is unclear bongo?

 

Once again, go to your lead pilot and express your distain for the operating limitations as published. 

 

You think you will still have a job?

[DD_bongodriver]

Ask any combat vet crump, just ask them please.

 

 

Your'e gonna love this

What part of Mandatory is unclear bongo?

 

Once again, go to your lead pilot and express your distain for the operating limitations as published. 

 

You think you will still have a job?

 

 

I am not a combat pilot engaged in active wartime service, of course I don't breech any rules, how is it so hard for you to grasp this simple concept?

[Crump]

 

So the outer wing guns of the late model Fw190As were removed.

 

 

What is so unclear about read the weight and balance sheet and follow the instructions???

 

Not only is that easy to do, is what they front line units did too!

 

Not the topic of this thread.  If you still unclear, start another one on that subject.

 

 

Ask any combat vet crump, just ask them please.

 

 

Ok,

 

 

Crumpp:  "Did did the manual become a mere guide when you were in combat?"

 

Crump replies:  "Not when it came to things like operating limitations.  Those are set by the physics and engineering limitation of the equipment. It is not fun changing ammo belts in the kill zone of an ambush but it is even worse dealing with a malfunction.  Especially one that is self induced because you were too stupid to operate the weapon properly."

Edited November 6, 2013 by Crump

[DD_bongodriver]

Montgomery Scott would be proud.

[Crump]

 

 I am not a combat pilot engaged in active wartime service, of course I don't breech any rules, how is it so hard for you to grasp this simple concept?

 

Exactly and it shows....

 

You think not adhering to the operating limitations has to do with lawyers and administrative bullshit.

 

You don't understand it has to do with not bleeding or bending sheet metal.  Those limitations are designed to take you to edge of performance and return to fight again.

 

Those limitations are built upon the best input available from the engineers, pilots, and mechanics.  That collective knowledge is captured, evaluated, and published for all to use in order to get maximum performance at the edge the machine can offer.

 

It is that simple. 

Edited November 6, 2013 by Crump

[MiloMorai]

What is so unclear about read the weight and balance sheet and follow the instructions???

 

Not only is that easy to do, is what they front line units did too!

 

Thanks for the confirmation that the outer wing guns could be removed.

 

There was a thread but it got locked because you couldn't admit you were wrong.

[Crump]

 

Thanks for the confirmation that the outer wing guns could be removed.

 

 

All of it can be summed up as "Read the correct documentation and follow what it says....."

Edited November 6, 2013 by Rama
Removed rude and insulting comments

[Rama]

Crump

Stop with rude and insulting comments please. This time I edited you post, next time, I'll apply the forum rules.

[Crump]

 

Crump

Stop with rude and insulting comments please. This time I edited you post, next time, I'll apply the forum rules.

 

I am the only one being rude?  Ok, got it.

[Sternjaeger]

Gents, can I please ask all interested parties (myself included of course) to desist from carrying on with this exchange and concentrate on the original thread, which is interesting and shouldn't be locked?

Edited November 6, 2013 by Sternjaeger

[DD_bongodriver]

Exactly and it shows....

 

You think not adhering to the operating limitations has to do with lawyers and administrative bullshit.

 

You don't understand it has to do with not bleeding or bending sheet metal.  Those limitations are designed to take you to edge of performance and return to fight again.

 

Those limitations are built upon the best input available from the engineers, pilots, and mechanics.  That collective knowledge is captured, evaluated, and published for all to use in order to get maximum performance at the edge the machine can offer.

 

It is that simple. 

 

 

I'm glad it shows that I am a civil pilot that follows regulations.

 

it really surprises me that someone claiming to be a professional pilot and aircraft engineer has simply no concept of the factorisation involved in the limits an aircraft flight manual gives, the published performance limits in the manual are not absolute limits set by physics but are in actual fact a safe envelope, there is always a margin beyond published performance (clearly you have not heard of measured/gross/net performance) many of the unauthorised modifications you have so far discredited have had many examples documented where the laws of physics did not break down, it was absolutely possible to remove the outer guns on the 190 and you even gave examples of when it was done.

 

Most aircraft perform 'better' than published performance limits, the published limits are not the hard line.

 

Gross Performance The average performance that a fleet of

aeroplanes should achieve if satisfactorily

maintained and flown in accordance with the

techniques described in the manual.

 

 

Net Performance

 

Net performance is the gross performance

diminished to allow for various contingencies

that cannot be accounted for operationally

e.g., variations in piloting technique,

 

temporary below average performance, etc.

It is improbable that the net performance will

not be achieved in operation, provided the

aeroplane is flown in accordance with the

recommended techniques

 

 

http://www.caa.co.uk/docs/33/CAP698.pdf

[Crump]

I'm glad it shows that I am a civil pilot that follows regulations.

 

it really surprises me that someone claiming to be a professional pilot and aircraft engineer has simply no concept of the factorisation involved in the limits an aircraft flight manual gives, the published performance limits in the manual are not absolute limits set by physics but are in actual fact a safe envelope, there is always a margin beyond published performance (clearly you have not heard of measured/gross/net performance) many of the unauthorised modifications you have so far discredited have had many examples documented where the laws of physics did not break down, it was absolutely possible to remove the outer guns on the 190 and you even gave examples of when it was done.

 

Most aircraft perform 'better' than published performance limits, the published limits are not the hard line.

 

Gross Performance The average performance that a fleet of

aeroplanes should achieve if satisfactorily

maintained and flown in accordance with the

techniques described in the manual.

 

 

Net Performance

 

Net performance is the gross performance

diminished to allow for various contingencies

that cannot be accounted for operationally

e.g., variations in piloting technique,

 

temporary below average performance, etc.

It is improbable that the net performance will

not be achieved in operation, provided the

aeroplane is flown in accordance with the

recommended techniques

 

 

http://www.caa.co.uk/docs/33/CAP698.pdf

 

 

You are confusing a few things here Bongo.

 

All aircraft performance is a percentage range over a mean.  The usual variation is about 3%.    This has nothing to do with violating the operating limitations.  It has to do with fit and finish, and normal manufacturing tolerances.

 

You are misapplying the information the CAA is telling you. 

 

 

Net performance is the gross performance

diminished to allow for various contingencies

that cannot be accounted for operationally

e.g., variations in piloting technique,

 

 

Right, it you cannot hold straight and level, slop thru turns, do not use trim properly......

 

You are not going to be as fast at the same power setting as a pilot who flies better than you. 

 

 

Most aircraft perform 'better' than published performance limits, the published limits are not the hard line...........

 

 

 

Some aircraft perform better than published performance and some aircraft do not! 

 

All aircraft performance is a percentage range over a mean.  The usual variation is about 3%.

Edited November 6, 2013 by Crump

[DD_bongodriver]

The usual variation is about 3%

 

 

Bingo!!! suddenly the hard line defined by the laws of physics disappears.

[Crump]

 

Gents, can I please ask all interested parties (myself included of course) to desist from carrying on with this exchange and concentrate on the original thread, which is interesting and shouldn't be locked?          

 

 

I agree. I would love to see a realistic depiction of these overboosted conditions.  The only real option is to use the operating limitations as published.  Yes, some time line information will have to be available.  Most of it is well known.

 

 

 

We know what the operating limitations say but it seems now the discussion is about discrediting those mandatory instructions as something that was routinely ignored.  

 

The argument is nobody paid any attention to the them anyway so I want my gameshape to be able to use a magic engine. 

 

So from a practical standpoint, where does one draw the line with that argument?  Community feelings perhaps?  Maybe we can look to the World Of Warcraft boards to see how disputes over Goblins and Wizards are resolved??

[DD_bongodriver]

We know what the operating limitations say but it seems now the discussion is about discrediting those mandatory instructions as something that was routinely ignored

 

 

Ok, what is 'actually' being said is

 

1. that the operating limitations were 'not' the ultimate physical edge of performance.

2. mandatory instructions were 'sometimes' ignored subject to known limitations being accepted, i.e. pilots had the throttle limits increased knowing they could get a little more than published performance with a small chance of hazard.

 

Maybe we can look to the World Of Warcraft boards to see how disputes over Goblins and Wizards are resolved??

 

 

head on over there and find out for us, we'll take care of business here.

Edited November 6, 2013 by Rama
edited to remove insulting comments

[ATAG_Slipstream]

Ah another of these threads.Sorry I looked now.

[thx1138]

Ah another of these threads.Sorry I looked now.

 

 

ROFLMAO !!

 

You NAILED it !

[NZTyphoon]

 

Or 60 uses.

 

 

....

 

 

 

Or one use.

 

Just to clear up some confusion: the V-1650-3 & 7 did not use ADI,  and the Pilot's Manual specified that the use of WEP meant that the engine had to be removed out for a 'knock-down inspection' after 5 hours of WEP use - while the engine had to be visually inspected by the ground crew,  there was no way it was overhauled after one 5 minute period of WEP, unless the pilot had been particularly brutal:

 

 

 

ADI was used on the V-1650-9 of the P-51H, but the Pilot's Manual does not specify that the engine had to be overhauled every time ADI was operated:

 

 

If the Merlin was as delicate as Crump likes to suggest it would have been useless as a war weapon.

Edited November 7, 2013 by NZTyphoon

[Dakpilot]

"there was no way it was overhauled after one 5 minute period of WEP,"

 

"If the Merlin was as delicate as Crump likes to suggest it would have been useless as a war weapon"

 

 

Crump clearly stated that it was overhauled at 5 hours of WEP use this has been said multiple times......

 

I think a lot of people are under a mis-conception of what a combat pilot really wants out of his aircraft, and the first  and most important thing is that it gets him HOME   

 

Cheers Dakpilot

[NZTyphoon]

Just clearing up any ambiguity - as it is this thread is called:

Water Methanol Injection Explained In Detail

so, instead of diverting into the WEP TBOs  of non water-methanol equipped engines, let's get back to the subject.

 

ADI had the advantages of keeping the cylinders cooler, reducing the risk of detonation at high boost pressures and eliminating the need to run rich fuel mixtures, while effectively increasing a fuel's octane number (through reduced detonation or knocking): read on:

 

 

While the use of ADI still created extra loadings on engine components, the heat stress on vital components was reduced compared with the use of high boost pressures and high octane fuel without ADI. In the case of the ADI equipped V-1650-9 the pilot still needed to log the use of water injection, which was only to be used in combat, and the ground crew needed to be told, the need to inspect the engine was not given the same priority as the V-1650-3 or 7.

 

For the R-2800 in the P-47 there were no restrictions on how long ADI could be used for, with a 15 gallon tank sufficient for 15 minutes:

 

P-47D Pilot's Training manual:

 

 

P-47D-25 et al  Pilot's Manual

 

 

 

From Graham White http://www.amazon.com/2800-Pratt-Whitneys-Dependable-Masterpiece/dp/0768002729

ADI Pratt & Whitney R-2800.pdf

 

[Kurfurst]

As for those who know later 109 engines were equiped with the water methanol injection system for the boost effect or as we in gaming call it WEP/ War Emegency Power.

 

http://www.youtube.com/watch?v=HkPFZWd8wj4

 

Coolest explanation of MW injection ever! 

[DD_Arthur]

Ah another of these threads.Sorry I looked now.

 

http://www.youtube.com/watch?v=NzlG28B-R8Y

[GOAT-ACEOFACES]

I'm going to have to save a copy of this thread

Because it was not that long ago that this same info was provided as justification for the P38L LATE in IL2 being allowed to operate at 70mp, at which time Crump was arguing against it, because it was not approved. Now that it suits his argument to say the opposite, he says the opposite!

[Crump]

I think a lot of people are under a mis-conception of what a combat pilot really wants out of his aircraft, and the first  and most important thing is that it gets him HOME   

 

 

 

Exactly.

 

They is also the misunderstanding that ADI or a simple manifold pressure increase are not overboosted conditions.  It is about increase in power over maximum continuous mark which is the 100% the engine could safely deliver continuously.

 

That is why the operating limitations in all POH's are mandatory instructions carrying the weight of law by convention.

[DD_bongodriver]

Was actively operating these aircraft in a combat environment part of the operating limitations?.......I'm pretty sure getting shot up never really had a section in the POH.

Edited November 11, 2013 by DD_bongodriver

[DD_fruitbat]

I'm amused by the notion of a ww2 pilot whose primary concern would be breaking civilian aviation law whilst someone was shooting at him. Hilarious!

Edited November 11, 2013 by fruitbat