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I don't know about your data, but soviet data give nominal rating "Номинальный режим" for the 105P and PA, of of 1100PS(1st stage, 2000m) and 1050PS(2nd stage, 4000m), for 2700 rpm at 910 mmHg.
1100 hp at 950 mm for 2600 rpm at SL for T.O. The time the PA was commited in production (1941) this rating was considered as nominal and used without time limits. The RPM loss was due to the climb/ TO configuration with heavy momentum from/to the prop.
I don't know who's the idiot that translated "nominal" to "combat rating" and moreover invented a 5' forcage rew in it.
It's a kind of a new aeronautical urban legend, something like that...
How do you translate "service rating" in russian? Difficult, since it never existed...
Maybe it dont had take off rating, cause they already did overboost the engine?? I did read that Kilmov himself was against the PF engine, cause he thought the reliability would suffer to much(i think the statistics show he was right). Of course, nevertheless they had to increase the power cause they needed it. Still it would be strange if there wasnt any limitation.The Klimov 105 had no "combat rating", no CP, no MP, no WEP, no X-leistung. The 105PF had no Take Off rating at all.
Higher rpm or higher boost, both lead to a hotter engine, while a higher boost very fast can cause detonations, specialy with not constand fuel quality.It never exists except maybe in test bench, the R-7 constant speed propeller regulator fitted in that plane wouldn't allow you to overturn the engine more than 2600-2700 rpm in level flight. It means: you increase boost, power if you're still at 2600 rpm, it will increase propeller path only - so speed, not RPM...
But some of our forum members seems to be particulary obtuse with that.
And i nevere heard about the PF-3 engine, serially fitted.
I should have written "The next successfully evolution...."No, the M-106 SK, very fiew were produced, and soon modified to M-105PF standards.
It had a single speed blower, giving 1350 hp at 2000+ m, at 1175 mm HG, 1250 hp at SL for "nominal rating", and 1360 hp at SL for TO.
No more CP, WEP, MP than usual...
The M-107, due to developpement difficulties had a "Боевой режим" that mean Combat Rating for the first time in Klimov engines history. But it's another story...
VG-33
ever from george of allaboutwarfare
...taken from?the speed for yak was in forsage so for around 5' minutes and the speed
Опробовать мотор на номинальной мощности. При нормальной работе мотора
показания приборов на номинальной мощности должны быть следующие:
- обороты 2600-2700 в минуту;
- наддув 1100+30 мм.рт.ст.;
- давление бензина 0,25-0,40 кг/см╓;
- давление масла 5-9 кг/см╓;
- давление масла, разжиженного бензином, не менее 4 кг/см╓.
if this is true I'll happily stand corrected, but I am rather curious as how this works mechanically.the R-7 constant speed propeller regulator fitted in that plane wouldn't allow you to overturn the engine more than 2600-2700 rpm in level flight.
if this is true I'll happily stand corrected, but I am rather curious as how this works mechanically.
This is a hydromatic constant speed propeller according the mechanical description (using a web based translator). The oil pressure valve is calibrated to a given max rpm as according to OKB/TsAGI specification at the time (sounds like it works basically like a turbo blow off valve, described as "borrowing neutral" when the max rpm is reached).
I'm less sure of that, it should be contained on the working gap/ bandpass. Maybe, can you adjust the regulator from 1200 (?) to 2700 rpm (+50-50 rpm), but maybe not 2800 or 3000, since it's outside the R-7 capabilities. Tt takes the R-43 AFAIC remember one from the same manufacturer.You are quite right and the prop limits max rpm to a given calibration, although this can be recalibrated by ground crew in the field (the same way as the blower regulator on American aircraft can be recalibrated in the field but the effect is max-rpm instead of max-manifold pressure). Mechanically speaking at least, from the description.
What is fairly likely is again you are quite right and the M-105 series were speed limited to 2600rpm by the prop, but in power on dives they'd tend to lag themselves to 2700rpm because of the hydromatic prop, then settle back down to 2600rpm at maximum engine speed pitch, so they're listed in the pilots handbook as 2600-2700rpm.
It's sure, there were political reasons too. Soviet engeeners were even more mass arrested than red army officiers, during Stalin's terror programm. In that context Klimov choosed lack of power complaints rather than massive engine breakdowns ones. So the M-105 overboost was undertaken under Yakovlev's initiative and respunsability, not Klimov's one.Until I can find a current source saying otherwise I'll stand corrected and go with this figure then.
do have to mention it is perfectly possible the given description is in the context of setting the neutrality of the pressure valve manually, by the pitch control, which is equally likely and thus describing how it limits engine speed doesn't necessarily restrict the maximum engine speed if the pilot sets the higher engine speed. At this point, because I've failed to find a current link otherwise I'll concede but there is still no explicit mechanical reason the M-105 series cannot engage a pilot induced war emergency setting.
It could, maybe. You need some different (non serial) features for that.Engines are mechanical things, and will do what you mechanically tell them to (even if it blows them). By definition a nominal setting can be exceeded for a short period of time wherever the pilot is prepared to risk overheating quickly and associated problems (seal integrity, pinging).
The Yak-7l (laminarny) had a laminar winf profile, no Yak-1,3,9 were so experimented.Hi,
Was there a special secret in the Yak1 to Yak9 airframe(laminar airfoil or so) or was the engine more powerfull than the datas say??
It depends on what Yak...No matter how long i look to the planes, i cant see where the 109G2 airframe was that much more wose than the Yak airframes.
It's seems rather confuse from your post, than strangewise...Strangewise other Yak´s(1/7/9) also with M-105PF-1 show "only" 515-520 km/h Sea level and 560-580km/h in around 3800m.
This increase was due to better quality manufacturing standards, and numerous small aerodynamic improvements. Only by sealing hermetic joints between the engine plates and thiknissing radiator fairing lips, TSAGI gained some 19 km/h for once. From theory, the best tear drop shaped fuselage for the lower Cd, should have 1 to 5/6 lengh/hight rate. It's without wing and interference losses. With them, it's more complicated. So the very thin fuselages like the Me-109 or Me-110 ones, have not systemetically the lowest Cd values for undersonic speeds, unlike popular prejudices say.Since the wingarea was greater than that of the Bf109G and also the fuselage dont seems to be smaler, it would be interesting to get some infos where the Yaks could gain such a advantage.
Any pilot can overspeed the motor, richen the mixture and use a variety of other little tricks to get what is commonly referred to as "war emergency power" for short field or heavy loaded operation.
Just as in the same way with the Allison there was a manufacturer limitation of 3000rpm, pilots in the field often oversped the engine for higher pressure calibration (as much as 72"Hg by some accounts), using 3200rpm which post war became the maximum limitation published (source: All Engines Data website).
But most importantly I'd like to point out that Operational Guidelines published do not necessarily reflect an aero engines capabilities nor even common practise in the field. The P-40 is an excellent example of this, and the conditions under which the Yak was operated is very similar, with varying fuel quality and "learn as you go" doctrine on its service use. Allison Division clearly revised its published operating procedures based on field experience at least twice, once in late 42 and then again about mid 43 increasing emergency maximums from 46"Hg to 52" successively and winding up with some 1580hp out of what was supposed to be an 1150hp motor.
Hello,
Just my other 5 pences (kopeks)
The Yak-7l (laminarny) had a laminar winf profile, no Yak-1,3,9 were so experimented.
The main secret, is that Yak-1 was a 1939 "normal" aerodynamics plane, the 109 a "good" 1935 one, altogether with Polikarpov's I-16, I-17 and Hurricane generation.
It depends on what Yak...
It's seems rather confuse from your post, than strangewise...
It did not worked like that. With the same PF-1 engine, Yak-7B speed reached progressivey from 495/500 km/h in mid 1942 to 535 in late 1943. The mid-statistical value for 1943 being 531 (with +12, -9 km/h sigma gap) km/h at SL. Then, the progress stopped.
This increase was due to better quality manufacturing standards, and numerous small aerodynamic improvements. Only by sealing hermetic joints between the engine plates and thiknissing radiator fairing lips, TSAGI gained some 19 km/h for once. From theory, the best tear drop shaped fuselage for the lower Cd, should have 1 to 5/6 lengh/hight rate. It's without wing and interference losses. With them, it's more complicated. So the very thin fuselages like the Me-109 or Me-110 ones, have not systemetically the lowest Cd values for undersonic speeds, unlike popular prejudices say.
Other way, Timppa is right, the Devil is in the details. For instance the Delta Cx (Cd in english) is 0.0012 for the Me-109 "square shapes" canopy, 0.0007 for the accurate P-39'one, and could have been easily reduced to 0,006 and less only with rounded section*.
So despite it's not integrated in the fuselage, the accurate Airacobra's bubbleon top canopy is much less draggy than the 109's razorback's one. It should have been the opposite, with some little efforts by german manufacturer.
Regards.
* Ostoslavski book "Aerodinamicheski Raschet" for engeneers from TsAGI wind-tunnel results
Is it inappropriate to suggest I kind of just feel "wrong" about thinking I can't step up a basic inline aero engine of a Hispano/Allison/Merlin type setup with some pilot control adjustments, at worst some very minor recalibration under the hood, for a short term, 2-5min extra emergency output. Every mechanical bone in my body says I can do that but I just can't find a reference. Bomber engines for example, say an A-20 or a B-25 never have an emergency rating listed in specifications published but they damn sure had one, a matter of pilot input for rough field and heavy load operation, but dealt with in pilot training rather than model-specific pilot handbooks. Full rich, overboost through the gate, overspeed for 1-2min. The engines really confined about this were the German ones once they started all that aeromechanical business, it added situational awareness but took a little pilot control out of hands, so once calibrated the controls only gave set limitations being all mechanically coordinated with throw weights and springs. Everybody else had much simpler, much more direct pilot-engineer controllability though, until well the 70's actually.
I may very well be wrong about the M-105, happy to concede since I can't find the link that mentioned 2800-3000rpm. And don't laugh, but I recall one of the IL2 arcade/sim handbooks mentions it.
OMG, but then again there's definitely something about a Napier I wouldn't be messing with, at 2300hp out of the box the only question anyway would be why for godsake.Unauthorized tinkering with the control boxes on the Napair Sabre engine by well meaning mechanics caused enough problems that it became a court martial offence.
piston acceleration, throw weight, bottom end, more excellent points (somebody give me modern alloys ).going from 2500rpm to 2700rpm increases the bearing loads by about 16% and at 2700rpm the piston speed is virtually the same as an Allison or Merlin at 3000rpm.
dammit I forgot about this, you'd think I was never an RAAF pilot cadet (you saying it did jog my memory, we were schooled on this but it was a very long time ago)WER settings required that each use be noted in the log book
The La-5FN airframe must have been absolut rubbish, still this radial powered plane was almost as fast as the 109K with same power and faster than the 2000 PS FW190A (according to the datas) .
What 109 got tested in the wind tunnel?
Same strange actually is the discrepancy between some La7 and La5FN datas, where the same engine and very similar airframe show a different of 40km/h over the full height.Knegel