A.P. 129 RAF Flying Training Manual, Part I - Landplanes
 

Engine limitations, boost control and cut-out/override.

Continued.

Thanks 41Sqn; attached is another explanation of boost types used by RAF engines from R A Beaumont A.F.R.Ae.S "Aeronautical Engineering: A Practical Guide for Everyone Connected With the Aero Industry"

(3) Override Boost - For the greatest possible power output for take-off or emergency, an increase in pressure above the normal take-off boost is permitted on some engines. This condition is used in conjunction with a special fuel. (p. 106)

The wording is similar to A.P.129, apart from noting that override boost was used in conjunction with a special fuel.

Wow, great stuff 41Sqn_Banks; thanks for sharing!

As an aside if I may, what equipment and set up are you using enabling you to obtain such beautiful images of these old manuals? Secondly, where do you get this stuff, lol! All I've been able to obtain of such material is monochrome/microfilmed copies from the archives...

Thanks for sharing Banks and NZTyphoon

It also notes that boost pressure is above what can be normally achieved with the take off boost override.

We know from the certificate altitude bench test that +10.5lbs was achieved with boost override on 87 Octane fuel.

The achievement of +12lbs is the rating for 100 Octane.

The Germans the same basic principle for in C3 Einspritzung. A very rich mixture to suppress detonation at very high manifold pressures.

Holy Christ, guys. Put this trash in the 100 octane thread where it belongs.

Very nice, thanks for sharing!

You can buy original manuals at second hand bookshops. For scanning I use a consumer book scanner (in my case Plustek OpticBook 3600 Plus)

No ones forcing you to read rare original documents that someone's very generously posted. Why don't you have a nice day.

@ 41Sqn_Banks, thank you very much for sharing, really interesting:cool:

Thanks so much for the information 41Sqn_Banks! I'll have to keep my eyes open for some of these manuals. They’re fabulous. I've had good success obtaining used books on line from Abebooks. I'll start running some searches there and see what comes up... Good tip on the book scanner too. If I can find a book worth scanning, I’ll get the scanner ;) The work you've done obtaining these manuals and then creating the lovely images is outstanding, not to mention what we've all learned from the material therein. Thanks again for sharing!

I wasn't referring to the documents that Banks posted. I was referring to the endless, monotonous 100 octane argument that's spilled over into YET ANOTHER thread.

People just can't let it go. Wanted to nip it in the bud.

comment 76 is interesting

So Banks....

You read it and we are in agreement that using the boost cut out was allowed on 87 Octane.

All I have presented to support you statement is general statement that allows to exceed the "flying Limitations" if situation demands it from April 1943. I will shows at the end of the post that statement does not apply to the "engine limitations". I also presented a general description of different engine systems from a training manual that describes the use of the override devices for take-off and the cut-out devices for emergency; without specifying fuel and engine.

All you have presented ... is nothing, you don't even quote or give the correct title and page or paragraph number to support your statements. That shows a lack in scientific research methods and lack of respect for your opponents. It just feels odd that I have to provide you with the sources to support your statements.

But nevertheless your statement is correct, it was generally allowed to use the override and the cut-out and sure there were engines that allowed the use with 87 octane fuel. Now let's apply these general statements on a particular engine type, for example the Merlin II/III.
The Merlin II/III didn't have a override for take-off like for example the Mercury XV, the take-off boost was +6.25 which is the boost obtained with enabled boost control and throttle lever fully open. But it did have a cut-out for emergency and it was allowed to use it, as can be seen in AP 1564A Pilot's Note Hurricane I from March 1939:
http://forum.1cpublishing.eu/attachm...1&d=1337373360

According to AP 1590B Merlin II and III Aero-engine from October 1938 the cut-out gives direct control over the throttle valve, thus "over-boosting is possible and care should be taken to avoid this":
http://forum.1cpublishing.eu/attachm...1&d=1337372707

So yes, it was certainly allowed to use the cut-out with 87 octane fuel as long as +6.25 boost was not exceeded, which is clearly and without any room for interpretation stated in Operational Notes for Pilots on Merlin II and III , January 1939: http://forum.1cpublishing.eu/attachm...0&d=1334682385

Note that it is clearly stated that this restriction applies even for "emergency" cases. As +6.25 boost is available with enabled boost control the only remaining logical reason to use the cut-out with 87 octane is in case of a failure of the boost control.

Then we have several additional documents that state the restriction of 100 octane fuel for the use of the cut-out for increased boost for "emergency" presented in this post: http://forum.1cpublishing.eu/showpos...postcount=1716

And just to add another one from AP 1590B A.L. 4, November 1940:
http://forum.1cpublishing.eu/attachm...1&d=1337375347
"necessitates the use of 100 octane fuel"


Your whole argument is based on this:
http://forum.1cpublishing.eu/attachm...8&d=1337207418

Do you realize that this statement is only related to "Flying limitations" in Part I of the manual and cannot be applied to the "Engine limitations" in Part II, which are outlined in the following:
http://forum.1cpublishing.eu/attachm...9&d=1337207425

And again this statement contradicts your theory. So even if can can provide a evidence that the use of the cut-out to exceed +6.25 boost with 87 octane allowed at any time, we have several document that mention the restriction of 100 octane in 1940. These restriction would have been introduced "in the light of Service experience and operational requirements".

Crumpp, Banks has weighed, measured and found you wanting.

You have nothing of any substance or fact in your argument.

What are you going to quote out of context next?

I wait with anticipation.

Crumpp, How about confining your arguments to the thread on 100 octane? Captain Doggles has a legitimate point - I posted pages from the Beaumont book to show that another historical document from the 1940s reflected what was printed in Banks' manual.

Here is another one from AP 1564A, Vol. I Section 8, July 1940:
"only when 100 octane fuel is used"

So why don't you just say:

YES, you are right.

It would be so much less tiresome to type for you.

:rolleyes:

Because you also claim in the other thread that combat reports that mention the use of boost control cut-out are not a proof for 100 octane fuel. And this claim is incorrect when applied to Merlin II/III aero-engines. Only the combat reports that describe a failure of the boost control are no proof for 87 or 100 octane fuel, all others are a definitive proof for 100 octane.

That is correct.

According to the RAF, the pilot could use boost cut out to achieve more power under any circumstances he felt balanced his risk.

Therefore, you will see it's use and it not surprising at all that running the engine at such an overloaded condition got attention from Dowding.

What a load of nonsense! Dowding referred specifically to +12 lbs boost which could only be attained with 100 Octane fuel - his memo had absolutely nothing to do with the rubbish you are trying to peddle;

http://i91.photobucket.com/albums/k3...g-page-001.jpg

http://i91.photobucket.com/albums/k3...g-page-002.jpg

"According to RAF" ... no words. Please quote a primary source that says that.

In case your opinion is based on Pilot's Notes General, 2nd Edition Part I Note A "Flying Limitations", Section 1 "Introduction", Paragraph (IV) it is not correct. This Paragraph IV does only apply to "Flying Limitations", which are handled in Part I Note A of the manual and are the following:
- Limiting Speeds
- Limiting Weights
- Manoeuvres not Permitted
- Normal Acceleration or g
- Flying in Bumpy Air
- C.G. Limits

This regulation does not apply to Part II Note A "Engine Limitations", which has it's own regulations.

Anyone can check this here: http://www.scribd.com/doc/40498672/A...dition-UK-1943

Anyway this is a manual from 1943. Pilot's Notes General 1st Edition from 1941 does not contain this regulation, in the contrary the 1st Edition clearly states 100 octane as requirements for use of cut-out (http://forum.1cpublishing.eu/attachm...0&d=1334727256, http://forum.1cpublishing.eu/attachm...1&d=1334727263). We are talking about combat reports from 1940.

But this has already been discusses. Why don't you just provide a primary source that really supports your claim and is not quoted out of context? Would be much less tiresome for everyone.

Thanks for posting Banks (plus NZtyphoon and others), really enjoyed going through these.

***Quasi Digression******
It sounds a bit kinky but the thing I miss with scans is the smell of old documents when you actually have them...I don't have flight test reports but collect period aviation books and love opening them and getting the full experience. I especially love the books from during or before the war, which usually get things totally wrong (109s are useless, 110s are superplanes, Jerry uses cannon as he is too scared to get close etc. :))

Just got the 1957 edition of "Night Fighter" written about the night fighter war by the operators who worked with John "cats eye" Cunningham...fantastic read.

I also have the 1941 edition of "Fighter Squadrons" by Noel Monks, about the French campaign. He seemed to be under the impression that Hurricanes did everything at "350mph" and the 109s were scared stiff of them :)

camber

Sure it applies and there is nothing in the wording of the engine limitations that negates part I, introduction.

Nothing at all. "should" is not "must" or "will"....

Aircraft Operating Notes are very specific and part of the airworthiness of the design.

The RAF gave their pilots license to violate those requirements at their own risk.

If i read correctly, the general notes are not aircraft specific? They also seem to be regarding the airframe rather than the engine, talking about flight handling and g pressure rather than aircraft specific engine limits. Part i) of the introduction looks at the airframe and structural failure, not engine failure. The entirety of part 1, other than flying methods to increase range, is discussing general flying techniques not engine management. The introduction to which this balancing of risk refers is to part 1- 'flying limitations' which discusses g force, trimming the aircraft etc. It is not in reference to part 2, look at the contents and you can see this!

It is in the regards of flying limitations, not engine limitations which is in a different section of the document!

It specifically says in engine limitations, Paragraph 3(ii):

"These figure provide a general guideline to the reasonable use of the engine. In combat and emergency other considerations may justify the pilot in disregarding these limitations"

You cannot look at a combat report that used an overboost condition as proof of 100 Octane fuel use.

Give it up Crumpp, all of your painfully nonsensical assumptions about 16 squadrons, based on pre war documents blah blah blah are a nonsense, as the Official War History Oil proves:

http://i91.photobucket.com/albums/k3...anerevised.jpg

http://i91.photobucket.com/albums/k3...9100Octane.jpg

http://i91.photobucket.com/albums/k3...anerevised.jpg

http://i91.photobucket.com/albums/k3...agerevised.jpg

"The pre-war activity had been based on the assumption that United States supplies would be denied Britain in the event of war....there was no anxiety in these early months about the prospects of supply."

Protest all you like Crumpp, make all the unproven assertions you want - just give up and stop wasting everyone's time, including your own.

I have to admit that I'm surprised that Crump expresses such faith in RAF and UK technological superiority, especially his belief that the RR Merlin could run at 12lb boost for 5 minutes with 87 octane fuel...;) As much as Crump might wish for this to be modelled in CloD, I should like to agree with NZtyphoon that the Merlin III required 100 octane fuel when pulling greater than 7lb boost.

However, if one reads the memo carefully, Dowding is referring to running the engine beyond it's oil and coolant limits during climbs and to oil starvation during inverted flight, and running the engine beyond 5 minutes as the major culprits in causing engine damage.

Let's look at the full Paragraph 3:

http://forum.1cpublishing.eu/attachm...0&d=1337207436

"these restrictions" in the context of the paragraph related to the "Duration and Flight Condition" restriction of the engine limitations. For example a pilot may use combat power for longer than 5 minutes or use combat power to climb to operational height in combat or emergency.
I'm afraid this quote does not support your theory.

Too right, nor did Dowding waste his time by writing to all frontline fighter pilots telling them to refrain from using boost override or exceeding boost limits for 87 octane fuel - why? - because he knew they were all using 100 Octane and was warning them against overuse of +12 lbs boost, as well as the other limits described by Seadog.

"In combat and emergency other considerations may justify the pilot in disregarding these limitations"

The Air Ministry gave license to violate the airworthiness of the aircraft. It is no wonder Dowding was concerned.

And yes, any pilot reading that would understand they do what they must to survive even if it means "disregarding these limitations" published in the Operating Notes.

There is no doubt that RAF pilots used whatever system was available to increase the limitations irregardless of fuel type.

No I think they tore up a lot of engines. In fact, I think it was to the point the Operations and Maintenance Chiefs expressed enough concern for Dowding to do something about it.

Absolute nonsense - once again for your benefit Crumpp, because you clearly have trouble reading beyond your preconceptions - Dowding specifically mentions +12 lbs boost and nothing else.

All of your suppositions about what the pilots will do is just that - pure conjecture without a single shred of evidence from you showing that pilots were so used to using 87 octane that in the heat of combat they pulled emergency boost expecting to do what exactly? Boost override was not available with 87 Octane fuel - period.

You have led the same song and dance routine over this "issue' over several threads now, and it is clear you are totally obsessed with your own interpretation of things, regardless of whatever evidence is placed in front of you. Go away and waste time elsewhere - this thread was not intended to be yet another argument over what Crumpp believes about 100 octane fuel.

... in March 1943.
... in August 1940.

There is no relation between the two. Also:
"A recent increase in the number of engine failures, due to failure of bearings, is an indication that some pilots are overstepping the engine limitations laid down in the Pilot's Handbook."
Doesn't sound like exceeding the limitations was a tolerated behavior in 1940.

Nonsense, boost override was and was even tested at service inspection. It was not authorized for use except at take off.

However the Air Ministry clearly states:

"In combat and emergency other considerations may justify the pilot in disregarding these limitations"

You just don't like that fact.

I was the one who told you that Operating Notes are mandatory to follow, linked to the airworthiness of the design, and done by convention.

They are very specific in what can and cannot be done. To include the specific passage the Air Ministry thought to include:

"In combat and emergency other considerations may justify the pilot in disregarding these limitations"

The Merlin II/III doesn't have a override for take-off, it only has a cut-out for emergency. A override for take-off is linked to extra rich mixture to preventing detonation. The cut-out does not increase mixture, thus requires higher octane fuel to prevent detonation.

- quoted wrong (it says "restrictions" and not "limitations")
- quoted out of context (the context are time and flight condition limits, not boost limitations)
- quoted comes from a later source (March 1943, thus not related to 1940)

The RAF fanboys would love to see a proof that 87 octane was not required for +12 boost with Merlin engines. No one cares about the type of fuel, it's the +12 boost everyone is interested in.

Speculation, not fact.

The only source you have are general aircraft notes given to all pilots in 1943? Next you will be saying that since part 3 gives information on the use and implementation of the Norden bombsight all hurricanes had a bomb aimer using the Norden! These are general aircraft notes, not aircraft or engine specific.

He has to cling to this, its all he has.

Dowding states that the the EBCO allows for 12lb boost for 5mins. I know you love the RR Merlin but would you really have us believe that this could be done with 87 octane fuel?

Exactly. It was used to test the engine at altitude during service maintenance.

THAT IS WHY YOU HAVE PILOT ANECDOTES OF FLYING AT +16 LBS ON 87 OCTANE!

If they tested the engine to 10.5lbs then a low engineering safety factor of 1.6 yields 16.8lbs. That pilot who did that was extremely lucky his engine did not destroy itself from detonation.

Where? Source please.

Weeeeeeeeeeeeee boooom...!

That's the sound of Crump's credibility cratering...:(

16lb boost with 87 octane...:rolleyes:

Crump an RAF fanboy...who knew?

As said: There is no "override" for Merlin II/III engines. There is no device for extra rich mixture for take-off. There is only a cut-out to disable the boost control. But this was not used for take-off, as maximum take-off boost is the regular rated boost of +6.25.

Great, show us the anecdote.

Once again you forgot atmospheric pressure in your calculation.
10.5lbs (+ 15.0) is 100%
16.0lbs (+ 15.0) is 121,56%
This is only a factor of 1.2; a factor of 1.6 would be +25.8lbs (+ 15.0).

Exactly. Only in emergency or special operational conditions the aircraft is flow at the "maximum rpm/boost for level flight" (later called "all out") limits and not above.

Read the description in AP129.

This is the most hilarious post I've ever read anywhere bar none:!:

I just can't believe that anyone could post something like this...even Kurfurst can't possibly agree with this!

The Me109e was limited to ~6lb boost with 87 octane fuel, and even late war with 100 octane the 109 could never pull more than ~12lb boost (even Kurfurst only claims ~14lbs), yet RAF fanboy Crumpp believes that the RR Merlin was so superior, in 1940, that it could pull 16lb boost with 87 octane fuel no less! And if it could pull 16lb boost with 87 octane and escape destruction, then 12lb boost would be no problem...:!:

Next Crump will be asking for an 18lb mod for the 100 octane RAF fighters...:grin:

Crumpp's faith in UK technology seems to know no bounds...;)

OOPS. Of course the British have to be different. Not any better, just different from everyone else in the world.

MAP - Manifold Absolute Pressure and it does not mean Manifold AIR pressure.

Good, I was thinking 1.6 is pushing it for the odds of somebody attempting it and surviving.

1.2 makes his story more credible, still very lucky but definately more credible that he was able to push it to +16lbs momentarily on 87 Octane.

"credible" ....:!:

Still no source, i wonder why.......

Read above it.....


"rpm limitations are directly associated with similar limitations on boost pressures also defined in relation to the operational condition".........

(vi) It may only be exceeded momentarily during aerobatics, fighting manoeuvers, or when diving.

Dowding:

This is related only to "maximum r.p.m. for level flight", described in paragraph (a) of the (vi), not related to "maximum boost for level flight" described in paragraph (b).
Of course the violation in these condition is not intended. It's caused by the constant speed propeller that has a certain delay before it can counteracts a increase/decrease of engine speed.

This is a training manual from 1937 and is general to all aircraft types of the time, so what it has to do with Merlin engines with 100 octane and +12lbs boost in 1940 is anybody's guess. Anyway I'd really like to see the anecdotes - and I note the word anecdotes - about the +16 lbs on 87 Octane... :rolleyes:

re the anecdotes,

http://www.youtube.com/watch?v=iIIuR...eature=related

I'm going to risk a newb. mistake of going back to the thread title, which was "A.P. 129 RAF Flying Training Manual, Part I - Landplanes". I have an unintentionally hilarious 1939 Hurricane manual, which is trying to explain how to deal with spins. It concludes with the following: I would love to get my hands on this paragraph 134, which probably says something like "get out of a spin before your altitude is too low." Does anyone have suggestions where to find it? I've got quite a collection of WW2 manuals, but mostly US.
Thanks.

If you send a personal message to 41_Sqn Banks, who originally posted the pages from the manual, he could most likely help.

At least no one has said 16 squadrons

Damn

Yes we are all still waiting for the identification of those 16 squadrons.

Just like we are still waiting on the proof the entire Fighter Command used 100 Octane despite it not being the specified fuel in any Operating Instructions outside of the Spitfire Mk II AND fuel testing was still in progress in mid-August 1940!!

:rolleyes:

Don't you guys think this is a dead horse???

In other, words you, or your good buddies, can't ID those 16 squadrons.

Does testing automatically end when something is approved?