Question on M.S.406

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The ratings Altea gave are for the max climb rating at 2600rpm, essentially in this case it is the maximum continuous engine speed with the maximum boost allowed. You could raise engine speed safely to 2800-3000rpm but only for a very short period, this would provide higher outputs, but it would be called a war emergency rating. True enough there is no overboost per se, but an extra 2-400rpm adds horsepower in the torque x engine speed equation from which horsepower is calculated, simply raising rpm increases horsepower if manifold pressure is maintained. Maximum boost is effectively overboost on Yaks anyway because the listed maximum boost pushes the handle just past its gatestop (ie. it goes a little further forward than the maximum rpm setting for the prop pitch where for normal engine settings the two are aligned together).

I think you'll find also the Soviet octane rating will vary by calculation, I was using motor method, which minimalises it. Your figure will be an average of motor method and rated octane number. You get the same thing with British fuels, their 100 octane is actually 130 RON. So compared to "Soviet 95 octane," British 100 octane fuel is 115 octane. In addition, in any case fuel qualities vary by where it was mined and the refining processes and additives used. For this reason fuel octanes compare poorly between varied sources, German 96 octane (also using the motor method) is equivalent to 100/130 early in the war and 100/150 late in the war (Crumpp who built the Fw190A "White 1" told me this himself as he had to research a great deal about wartime fuels for his rebuilt BMW801 motor). British 87 octane was a typical prewar aviation fuel, used on most of their fighters and good for +6lbs on a Merlin engine. Upon the British adoption of 100 octane aviation fuel for fighters the Merlins were recalibrated for +12lbs. The +12lbs of Hurricane lend lease deliveries could not be used with Soviet fighter aviation fuel in 1941 and these engines had to be derated to no more than +6lbs. This is the reason for my likening of the Soviet fuel quality as (equivalent to) 87 octane British aviation fuel. American 91 octane fuel is the same as British 87 octane, again good for only +6lbs on a Merlin (or +8lbs or 47" Hg on an Allison). There is no doubt given the VK-107 and M82FN development during 1943 that Soviet fuel quality had improved, not for the least reason being the lend lease LF MkV Spits and Airacobras received did not have to be derated for the previous demonstrably poor Soviet fuel quality of 1941.

All I can say is not everything may be recorded for prosperity, but are still indicated by circumstance and physical example, by simple engineering realities. Many, if not most, if not all VVS a/c from 1943 could not possibly be run on the fuel type for which the Hurricanes had to be derated to +6lbs, the Soviet fuel type available in 1941.

About the engine settings, this is exactly the same as the issue about the listed output of the F3R Allison in the P40E, 1150hp at 11000ft says the book but this is not the maximum output of the engine which was first cleared for 1480hp to ~7000ft by Allison Division during 1941 and then finally 1680hp to 5000ft. Maximum pressure altitude may be increased by ram effect.
Yet still engineering tables list 1150hp for the Allison at 3000-3200rpm. And what's more at 3200rpm using ram effect you can manage over 1700hp pretty surely, again if you use a war emergency setting. This is frequently not even listed in manufacturer specifications, who tend to offer only the International rating (maximum continuous power) or the maximum climb rating (military power). Some give maximum take off power.

The 1100hp rating for the M-105P is for 2600rpm (as mentioned above, max continuous engine speed with maximum boost). The motor can do 3000rpm (though it is not advised to exceed 2800rpm, which is the listed maximum engine speed). You do the math. Same argument for the other motors. Just to be clear for any translation difficulties for non-english native tongues, pretty much any engine of the type can be run at a continuous setting, or a medium period military setting for climbing regimes, or an all out war emergency setting which overheats the motor quickly. This is because aero engine settings were almost completely under the control of the pilot back then and he had far more control over the way the engine handled than what you get with a flight computer or automatic management system, control of the motor was very manual. This was the reason for operational procedures being a matter of manufacturer released guidelines, any pilot could if he wanted to exceed the factory rated specifications for operation of the engine, exceed its maximum safe engine speed, ask his mechanic to recalibrate the throttle to the boost regulator for a higher than maximum overboost. A pilot could always do these things, he was not supposed to but sometimes pilots found their own better than manufacturer settings during actual service, and the manufacturer revised their operating procedures to suit. This happened exactly with the F-series Allison for example. In any case pretty much any engine of this type can be run at a military, continuous or a war emergency setting, even if the manufacturer only lists output ratings for one of these engine settings. Did you know the DB601A has a war emergency rating which is also simply a raised engine speed, or that the output listed for the Merlin 45 in the MkV Spit is a war emergency rating which can only be maintained for 5min, it's more like 1150hp just like an Allison at the 30min military setting, and as mentioned the Allison's rating is for military power.

I'm still trying to find the Russian aviation website article I read about field recalibration for the PF boost, it was a TsAGI article, I'll link it when I do. The carburettor was rejetted to prevent predetonation (the mixture needed to be richened) but the new pistons came for the 115cm boost of the PF2 iirc. They used to be cast and they switched to alloy for the PF2.
The PF2 entered service with the Yak-9 and this motor is not interchangeable with the 105P, true enough different pistons and perhaps reduction gear I don't know. The PF though was just a boost recalibration and it was fuel quality associated, I remember this clearly. The article which described test flights by TsAGI of various production improvements clearly stated no modifications to the motor itself was made between 105P and PF motors, it made a point of it.
If you have links with better detail I'd appreciate it. I'm not that excited that I'm going to go buy some books though, this is just a web forum challenge. I'm already comfortable with much of my research thus far.
 
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Aviation fuels from WWII do not really compare to motor fuels of today.

Each countery may have had their own specifications that included not only octane rating (how ever a country decided to measure it) but octane ratings at lean and rich settings ( british were the FIRST to specify this) BTUs per pound, Reid vapor pressure ratings, percentage of of Aromatics permitted, evaporation rates, sulfer content, amount of gum, even the max and min amounts of dye.

Becasue of the different base stocks, gasoline of the same basic "octane rating" did perform differently.

Specifications also changed from before the war to during the war to post war. Some fuel's specifications might not have changed while others did. Something else to watch for, at least in the case of the US, is that military fuel specifications did not always match commercial aviation fuel specs. By 1951 this even went to different allowable limits for the amount of lead per gallon for the two different 100/130 fuels.

As far as "over speeding" engines goes, this can be gotten away with while diving to some extent. Throttle is part closed and the propeller is actually driving the engine. THe partially shut throttle restricts the amount of intake air and so limits the amout of power the engine is producing. Over revving the engine under full throttle conditions is a bit riskier.
On a gear driven supercharger there is no seperate control over over the supercharger speed. I have one source that says high gear on the M -105 engine was 10 to 1 so if the engine is turning 2600rpm the supercharger is turning 26,000rpm. inceasing the RPM by of the engine by 300 means the supercharger HAS TO increase speed by 3000rpm. since the pressure delivered by the supercharger is proportional to the square of the impeller tip speed we can see that,unless there are restictions in the intake and outtakes (ducting/manifolds) there is going to be a very large increase in airflow and power. This inceases the manifold pressure as the rpm goes up.
Both the origianol Hispano and the Russian M-105 were rather large engines (displacement wise) on the order of 36 liters or so or just a bit under a Griffon. They had a longer stroke than a Griffon and yet weighed less than a Merlin or Allison. Given that rod bearing loads go up with the square of the speed and the light construction of these engines I am not sure I see much overrevving/overboosting of these engines.
I am sure it was done on occasion but some of the WAR emergency power ratings were only approved after a test engine had gone 7 1/2 hours on test bench at that rating. THis is to allow for production variations between engines so that the WORST engine out of every 100 doesn't blow itself up in a matter of seconds when abused in this way.

As an aside I believe it almost became a courtmartial offense for British mechanics to "modify" the boost setting controls on the Napair Sabre engine after more than a couple of engines were destroyed by mechanics who "knew better" than the factory engineers
 
Vincenzo said:
Altea are you sure that nominal it's same of max continous ?
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From the definition itself, it is. Or should be...

But caution!!!

- It's just for French and by extension, Soviet rules and procedures. Elsewhere it's certainly different.
- Max continuous power for an engine, does not mean max continuous speed for a plane for a lot of reason, mainly coolant ones.
- There was a lot of possible arrangements on some concrete cases. For example the Shvetsov M-62 for Polikarpov fighters had no official time limit, but the same reucted M-62IR for civilian planes (Li-2, An-2) was limited for one hour in "nominal" flight. For that price the M 62IR had a TBO of 400 hours (1 000 hours ower days) instead of only 100-150 for the militar one (M 62).
 
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Are these any help in identifying bits ?. Taken at Flying Legends at Duxford over the past few years, she is quite a nifty little performer in the air....(allthough they did have a few problems with the clockwork this year)
 

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Geedee said:
Are these any help in identifying bits ?. Taken at Flying Legends at Duxford over the past few years, she is quite a nifty little performer in the air....(allthough they did have a few problems with the clockwork this year)
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It's tiny
it makes a Bf109 look big
 
Thanks Gary
really nice photos. Seems to me ex-Swiss D-3801 or -3802 because of it has a fixed radiator but only 2 wing guns but of course French had also MS 406/410 hybrids

Juha
 
The ratings Altea gave are for the max climb rating at 2600rpm, essentially in this case it is the maximum continuous engine speed with the maximum boost allowed.
Click to expand...

Altea perfectly knows what he gaves you; the max power available with Klimov 105P and PF's. Whatever you use it for climbing or just flying at max speed horizontaly both at 2600rpm. Only propeller path is changing in this case. Exactly as with your car, if you've got one with a gear box..


You could raise engine speed safely to 2800-3000rpm but only for a very short period, this would provide higher outputs, but it would be called a war emergency rating.
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I don't know what engine could you raise at 2800-3000 rpm, but not the Hispano-Suiza and not the Klimov 105 as i previously said.
The facts are that your boost and fuel levers, fully open on thrust position, the engine will run at 2700 rpm only or 2550-2600 with the R-7 constant speed propeller regulator slightly reduced for climbing or new engine (less than 20 hours wear) limitations procedures.

So it's why i said there were no emergency rating on Klimov 105PF. Even if pilots could cheat over the 105P at low level with 975 mm boost instead of the nominal 910 mm, it was not calculated and not garanteed for that. This possibility on the M-105PF/PF-2 did no longer existed: it had 1050mm boost at best!




True enough there is no overboost per se, but an extra 2-400rpm adds horsepower in the torque x engine speed equation from which horsepower is calculated, simply raising rpm increases horsepower if manifold pressure is maintained.
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I'm not sure of that. Have you got a torque/rpm curve? The M 105 torque is probably decreasing over 2600 rpm. Even the Klimov M-106P and M-106SK ran at 2600 rpm for its 1350 hp max power, but at higher boost.

Do you understand how an engine work?
To make it run at 2-400 rpm more you need to inject more fuel, more air. It takes an other (bigger) supercharger, other (bigger) carburettor, injectors, valves, maybe other plugs and switch advance circuitry. Take over the R-7 path regulator an replace by an other one. Can you explain us how can you do that with a serial Klimov M-105P or PF? I don't know about a lot of concrete examples, just one with certainly non-serial engines.


No it's impossible, see higher. You can't get forward physically as in your before quoted car in standard configuration.


You have confused/mixed a lot of things having no relationships between them: MON, RON, Poor mixture, rich mixture, aviation fuel tests, supercharged tests... The soviet 95 octanes fuel had exactly the behavior of a 95% iso-octane and 5% heptane mixture fuel on soviet CFR.

It (the 4B-78 ) was obtained by adding 4 cm cub of TEL to a natural 78 octanes kg raffinated from Bakou fuel. You can try owerdays, it's still making 95 octanes by the same method.

Yaks were not using it, only M-82F/FN. The 2B-78 to 3B-78 mixtures for Klimovs 103A, 105, 106. And some 3.5B-78 for the M-107.

The German C-3 fuel, quoted at 94 by the TsAGI, had exactly the behaviour of a 93% iso-octane and 7% heptane mixture, on soviet CFR tests, that was running faster AFAIK (1500 rpm) than the german synthetical one.
From russian source:

И последне не надо думать. что даже в такой малости три единицы октанового числа советский бензин уступал немецкой "синтетике" - у нас и у немцев были разные способы измерения октанового показателя. Т.ч. наше "93" у немцев было бы "96".



To obtain classical pre-war 87 octane fuel, soviets could use either:

- 3B-70 mixture
- 1.5B-74 one
- 1B-78 as well

Probably British had not produced a special supercharger for soviet 1941's standard 91-95 graded fuels that could range from 8,4712 to 10,8613 lbs rates.
Moreover, soviets had a lot of B-70 fuel basis to spend, that could not be used on very last engines.

BTW the rumanian petrol used by germans could naturally gave a 74 octanes mixtures basis at best, and some rare parts at 76. Germans were not using Eugène Houdry's cracking methods, AFAIK. But soviets with american help, did. In 1943 they were building 6 such a reffineries under licence. So late in the war they had 95 (soviet number) basis fuels that could provide from 96 (1B-95) to 115 (4B-95) octane number fuels.





In 1942-1943 soviet fuel qulity had failed, because of , grozny , majkop production 78 basis reduction. Spits and Airacobras were simply using LL fuel supplys, if they were not derated.





It's just your own supposals and extrapolations, BTW all false in our particular case....

About the engine settings, this is exactly the same as the issue about the listed output of the F3R Allison in the P40E, 1150hp at etc....rating (military power). Some give maximum take off power.
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On Allisons, maybe...I don't know.

The 1100hp rating for the M-105P is for 2600rpm (as mentioned above, max continuous engine speed with maximum boost). The motor can do 3000rpm (though it is not advised to exceed 2800rpm, which is the listed maximum engine speed).
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On Klimovs, no! There we strictly no device or features on that engine, that could allow to do better than factory-rated power! Except heavy modifications from factory, certainly not in front-line units!



Might be for some engines, certainly not for any of them. I don't understant your obstination to establish some parallels, that in fact never existed, from a country to another rules and procedures.




I know, but there's no analogy for that with french Hispano-Suiza or soviet-Klimov engines, except experimental ones in design bureau's benchtests. This is a cultural exception.


I have already send you the values from the TsAGI editions book, Samoletostroenie.


The PF-2 entered service with the Yak-3 in 1944. The PF with Yak-1 in mid-1942.


You can read pilots manual for the LaGG-3 both with 105PA and 105PF engines on:

??????????

Regards
 
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Even the Allsion wasn't that tolerant of over revving.

Froma training manual on the P-40, ANY over revving past 3120 rpm was to reported and written up so that appropriate inspections and maintence could be perormed as even a few seconds at that speed could cause bearing trouble on later flights.
 
VG-33 said:
Having a constant-speed propeller, pilot and fuel tank protection, it performed well during the "fonny war" against 109D, but was soon overclassed by the E model.
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Propeller are not constant speed propeller.
- Chauviere propeller série 351, manual control, two pitch(pneumatic)
- Ratier propeller série 1495, manual control, two pitch(electric).
It's possible to obtain any position between low pitch and high pitch but it's not recommended by Morane Saulnier.

The only protection is an armour plate behind the head of pilot.


I hope you scuse me my very bad langage....

under the caracteristic of engine Hispano Suiza 12Y and curve






I sell a handbook of maintenance and repair of Morane Saulnier 406 , it's an original handbook (1939)
"notice d'entretien et de réparation de l'avion Morane Saulnier 406C1, 112 pages 66 planches dépliantes - 500€
 
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Hello waroff
the lower fuel tank in MS 406 was rubber coated and some of the 406s of Finnish AF had CS propeller.

and thanks for the graphs.

Juha
 
Juha said:
Hello waroff
the lower fuel tank in MS 406 was rubber coated and some of the 406s of Finnish AF had CS propeller.

and thanks for the graphs.

Juha
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Early MS 406 hav'nt self sealant tank.
Perhaps latest MS 406, and 410, 412, morko morane.
for CS propeller, engine is not HS12Y and propeller are not Chauviere or Ratier
MS 406 fench Armée de l'Air of Bataille de France and MS406 Finnish Air Force are very different!
their aspect are similar but they are different.
 
Hello waroff
According to part and equipment list dated 15 Jan 41, in all Finnish MS 406s the lower, 325l, fuel tank was rubber coated, and at that time we had only those MS406s we had got during the Winter War (30 Nov 39 – 13 March 40). Of course it is possible that Finns coated them between the end of the Winter War and the beginning of 1941. The Finnish AF 406s/410s had Chauviére 351, the most common, Hispano-Suiza 10B, Ratier 1607 or Soviet Hamilton Standard copy propeller. We also tested Swiss Escher Wyss propeller.

Juha
 
Hello Juha,
thank's for your information.
Chauvière propeller serie 351 can't be use as CS propeller.
Ratier 1607 had control auto (CS), or manual.
Ratier 1495 only manual control.
After 40, I dont know...

Waroff
 
Hello Waroff
yes when I wrote that some Finnish AF 406s/410s had CS propeller I meant those with Ratier 1607 or Escher Wyss.I'd check the Soviet Hamilton Standard copy from my SB material, it probably wasn't CS, but today I don't have time.

The coating of the lower fuel tank is not mentioned among the modifications made by Finns in Raunio's book on Finnish AF fighters. When I have time I'll check what I have on French 406s/410s. But Finns fitted back armour.

Juha
 
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