LA-7 fuel consumption questions Part II

[F4UDOA]

I will start this post off by just showing the English translation of the La-7 VVS flight test. I am highlighting the part that clearly shows the fuel consumption at sea level and the top speed clearly matches HTC's charts at 357MPH at MIL power.

This shows the duration at Mil power being 35 minutes. In the MA this would yield a duration of 17.5minutes and currently I believe it is 27minutes. Also at the next altitude of 3,000meters duration drops to 33 minutes.

The rest of th test including WEP test are in the next post. There are no WEP fuel consumtpions listed.

Fund of NII VVS, inv. 485716, file 273

         Approved. Chief Engineer of VVS A.Repin, 11 Oct 1944

                        THE STATEMENT
on results of verification trials of a serial La-7 with ASh-82FN engine and
                 VISh-105V-4 propeller, D=3.1m
        /ac.No 45210203, prod. in July 1944 by factory No 21/


                   Air combat with Me-109G-4

In horizontal manoeuvring up to 5000m the La-7 gets on the tail of
the Me-109 for an aimed shot after 3-4 turns. Above 5000 m the advantage of
La-7 in horizontal manoeuvre decreases. At an altitude of 7000m horizontal
manoeuverability of both planes is equal.

In vertical manoeuvring the La-7 has an obvious advantage over the Me-109
up to 3500m and can keep an altitude dominance of 150m during combat. When
it reaches an altitude of 3500m the La-7 slightly loses its superiority over
the Me-109 in vertical manoeuverability, but even at 7000m the La-7 can
maintain a dominance of about 40-50m. At 6500-7000m the vertical
manoeuverability of both planes is equal.

The La-7 accelerates into the dive faster than the Me-109 and therefore can
reduce the distance to an escaping target. However, in continuous dive the
Me-109 increases its speed faster after initial acceleration and departs from
the La-7.

------------------------------------------------------------------------
========================page02.gif======================================

          Approved. 1st Deputy Chief of GK NII VVS Losyukov. 6 Jan 1945.

                          REPORT No 2
on results of flight trials for fuel consumption and range measurements
of La-7 No38103254 with ASh-82FN engine and VISh-105V-4 propeller.

                     The object of research

La-7 No 38103254 produced by plant No 381... Total weight 3265 kg, fuel tanks
capacity - 460 litres. The landing-gear and the tail wheel were up,
the canopy was closed, the cap of oil-cooler and the skirt of engine cowl
were set "along the flood" (feathered).

                    The results of the tests.

The measurements of fuel consumption with working engine had been carried
out on the ground and during a climb at max climb rate. As a result it has
been established that fuel consumption of a working engine is 2.35 l/min
on the ground (during warm-up and engine test, taxiing to and from the
starting position).

Fuel consumption at climb to H at maximum climb rate mode, in litres
                          n=2400RPM

H,m       1000    2000    3000    4000    5000    6000    7000
Q,litres    15      25      35      45      55      65      80
IAS, km/h  270     270     270     265     260     255     250


Chart of range and level flight duration of a/c La-7 No38103254 at different
flight modes at V/n=const (constant speed and RPM), G tot=3265kg (total
weight) and V fuel=460 l (fuel volume)

n,  Supercharg. Speed, km/h     q,      Qf,       Till the dry tank:
RPM  pressure,    IAS    TAS  lit./km  lit./h    Range of    Level flight
     mm of merc.                               level flight,   duration,
     pile                                          km           h-min

H=1000m (1st speed of supercharger), fuel supply for level flight - 365 l

2400   1020       575    608   1.020     620       355          0-35
2200    875       530    560   0.800     448       455          0-49
2000    745       480    508   0.655     333       555          1-06
1800    665       430    455   0.585     266       625          1-22
1600    610       385    407   0.560     228       650          1-36
1500    580       360    380   0.550     209       665          1-45

H=3000m (1st speed of supercharger), fuel supply for level flight - 345 l

2400    990       554    644   0.975     628       355          0-33
2200    830       510    588   0.745     438       460          0-47
2000    705       460    532   0.620     330       555          1-03
1800    615       415    480   0.575     276       600          1-15
1600    560       370    428   0.555     238       620          1-27
1500    545       345    400   0.550     220       625          1-34

H=5000m (2nd speed of supercharger), fuel supply for level flight - 325 l

2400   1020       513    658   0.910     600       355          0-32
2200    840       470    604   0.700     423       465          0-46
2000    720       430    554   0.600     333       540          0-58
1800    630       385    496   0.560     278       580          1-10
1600    590       340    440   0.550     242       590          1-20

H=7000m (2nd speed of supercharger), fuel supply for level flight - 300 l

2400    870       454    647   0.735     476       405          0-38
2200    685       415    593   0.570     338       525          0-53
2000    590       380    544   0.500     272       600          1-06
1800    515       340    490   0.460     225       650          1-20
1600    465       300    433   0.450     195       665          1-32

Notes:

1. For range and flight duration calculations the following fuel consumptions
are taken into account:

========================page03.gif======================================

a) for engine work on the ground (warming-up and engine test, taxiing to and
from the start) 35 l per 15 min;

b) for climb to: 1000m - 15 l; 3000 m - 55 l; 7000 m - 80 l;
c) for circle flight before landing - 45 l.

2. To obtain the values of technical range and flight duration add the
following range and time figures to the table values respectively:
1000m -  5km, 1 min
3000m - 15km, 3 min
5000m - 25km, 5 min
7000m - 40km, 8 min


The table of range and flight duration for La-7 No 38103254 with
G full=3265kg, full tank fuel supply - 460 l.

Mode   Mode values                                      Level flight
                                                      up to dry tanks:
                                                     Range, km     duration,
                                                                   h-min
                                                                   
Max.   H=1000m(1st sup.sp.),n=2400, Ps=1020mm Me.pl.    355        0-35
speed    3000  1              2400      990             355        0-33
         5000  2              2400     1020             355        0-32
         7000  2              2400      870             405        0-38

Fast   H=1000m(1st sup.sp.),n=2160, IAS=518 km/h        485        0-53
range    3000  1              2160      498             490        0-51
(0.9     5000  2              2160      462             485        0-49
Vmax)    7000  2              2160      408             545        0-56

Near   H=5000m(2nd sup.sp.),n=1810, IAS=388 km/h        580        1-10
fast range                          TAS=500 km/h

Optim. H=1000m(1st sup.sp.),n=1500, IAS=360 km/h        665        1-45
mode     3000  1              1500      345             625        1-34
         5000  2              1600      340             590        1-20
         7000  2              1600      300             665        1-32

[F4UDOA]

------------------------------------------------------------------------
========================page04.gif======================================

                      Approved. Chief engineer of VVS A.Repin, 21 Jun 45

                       The statement No 112
on results of verification trials of La-7 serial plane with ASh-82FN engine
and VISh-105V-4 propeller D=3.1m, equipped with hydraulically controlled
              dust filter and new ventilation of cockpit
        / a/c No 45213276, plant No 21, prod. of April 1945 /


        Table of max. horizontal speeds

H standard,             TAS, km/h
  m               nominmal, n=2400 RPM     WEP, n=2500 RPM

    0                   580                     616
 1000                   604                     639
 2000                   626                     661
 2200 1)                 -                      666
 3000                   649                     657
 3250 2)                654                     654
 4000                   645                      -
 5000                   651                      -
 6000                   672                      -
 6250 3)                677                      -
 7000                   666                      -
 8000                   651                      -

1) - 1st altitude boundary with WEP
2) - 1st altitude boundary without WEP
3) - 2nd altitude boundary without WEP

              Table of max. climb rates

H st., m   Vy (vert. speed), m/s    Time, min           IAS, km/h
              nominal   WEP       nominal   WEP

    0          20      24.2        0        0            264
 1000          20      24.2        0.85     0.65         259
 1600 1)        -      24.2         -       1             -
 2000          20        -         1.7      1.3          253
 2650 2)       20        -          -        -            -
 3000          18.6      -         2.6      2.2          246
 4000          15        -         3.55     3.2          239
 5000          15        -         4.65     4.3          232
 5100 3)       15        -         4.75     4.4           -
 6000          12.7      -         5.9      5.45         224
 7000          10.2      -         7.4       -           214
 8000           7.6      -         9.3       -           204
 9000           5        -        12.0       -           189
10000           2.4      -        16.6       -           166
10750 4)        0.5      -        26.0       -            -

1) - 1st altitude boundary with WEP
2) - 1st altitude boundary without WEP
3) - 2nd altitude boundary
4) - practical ceiling

========================page05.gif======================================

                     Maneuverability (nominal/WEP)

BFM     Init.IAS, km/h   Result.IAS, km/h   Time, sec.    Change of alt., m
        1000m    5000m   1000m    5000m   1000m    5000m   1000m    5000m

360deg. turn:
- left   340      300     340      300     19.5     27       0        0
- right  340      300     340      300     18.5     26       0        0

Combat turn:
- left   550/580  470     270      260     17       15    1100/1300  850
- right  550/580  470     270      260     17       15    1100/1300  850

Split-S (overturn, upheaval):
- left     -      260      -       380      -        -       -       800
- right    -      260      -       380      -        -       -       800

                        Take-off capabilities

Flaps  Weight,   n,   P superch.   Take-off Time,  Take-off    Take-off dist.
         kg     RPM  mm of Me pile  run, m    s   speed, km/h        m

Retrct. 3275   2400      1000        380    14.2     175          1000
Retrct. 3275   2500      1120        335    12.7     175           880


                        Landing  capabilities

Flaps Brakes Weight,  Landing  Time,  Landing     Landing dist.
       usage   kg      run, m    s   speed, km/h        m

Full   Used   3035      440    17.9     135           1000

*) Take-off and landing distances are for 25m high obstractles.


Range and flight duration for weight of 3275kg and 328kg(445 l) of fuel.

Mode    Altitude,m    Speed,km/h  n,RPM   P sup,    Till dry tanks:
      indic.  stand.  IAS    TAS         mm Me.pl.    tech.   tech.flight
                                                    range,km  dur., h-min
Max.   1000    1020   358    376   1500    620        635        1-41
range

------------------------------------------------------------------------
========================page06.gif======================================

                      Approved. Chief engineer of VVS A.Repin, 29 Dec 45

                     The statement No 222
on results of verification trials of La-7 with ASh-82FN engine and VISh-105V-4
propeller in order to determine manoeuverability characteristics
/ a/c No 38100869, plant No 381, prod. of July 1945 /

Lead pilots: major Kubyshkin A.G., captain Pikulenko D.G.

                           Brief data

The complete verification trials were to determine the difference between right
and left manoeuvres and influence of the engine mode on manoeuverability
characteristics (360deg. turns at 1000 and 5000m, combat turns and split-Ss)
are to be done for the first time.

The plane has been tested with normal flight weight of 3310kg at nominal
engine mode (Ps=1000mm of Me. pile, n=2400RPM).

                          Conclusion.

1. La-7 does manoeuvres better backward to propeller rotation's direction,
as well as Yak-3.

2. The difference between right and left manoeuvres for La-7 is less than
for Yak-3 (the difference in time of right and left turns is 0.3-0.7 sec
for La-7 and 1.0 sec for Yak-3).

                          Inferences.

1. La-7 No 38100869 has following manoeuverability characteristics:

a) optimum extreme sustained turn

H, m  Direction  IAS,km/h  Time,sec   Radius,m  Bank angle,deg.

1000  right      320-340   21.0-21.2  305-335    70.7-71.4
      left       320-340   20.7-21.0  290-315    71.2-71.5
5000  right      280-290     30.7     485-500    64.3-64.8
      left       280-290     30.0     470-490    65.4-65.7


b) combat turn

Init.  Direction  Init.     result.   Alt.gained,m  Time,sec
H, m              IAS,km/h  IAS,km/h

1000   right       560       270         1170         24
       left        560       270         1170         24
5000   right       460       240          930         23
       left        460       240          950         23


c) split-S

Init.  Direction  Init.     result.     Alt.loss,m  Time,sec
H, m             IAS,km/h  IAS,km/h

2000   right       235       350          595         13
       left        235       345          575         13
5000   right       225       350          820         16
       left        225       340          790         15


2. The characteristics of optimum multiple (sustained) 360deg. turns obtained
of both the pilots are practically identical (the differences are in
admissible limits).

3. The combat turns' characteristics at H=1000 m obtained by both pilots
are practically identical.

4. The combat turns' characteristics at H=1000 m obtained by both pilots
are slightly different in gained altitude. The altitude addition obtained
by each pilot differs from mean turn in +20-25m. Such a difference should
be considered as the standard accuracy of climb definition at H=5000.

5. The split-S data obtained by both pilots are slightly different
in altitude loss, the time to perform and resulting speed. The altitude
loss obtained by each pilot differs from mean result in +20-25m. Time of
manoeuvres are different from the mean value by 1 sec, and the difference
in resulting speeds is 10 km/h IAS. Such a difference should be considered
as the standard accuracy of split-s data definition at H=2000 and 5000m.

6. Manoeuvres, performed in direction opposite to propeller rotation
(left for La-7), are better than ones performed in other direction.

------------------------------------------------------------------------
========================page07.gif======================================
diagr01.gif
*** Diagram: "La-7 N 45210139 (verification trials in LII NKAP)"

[F4UDOA]

------------------------------------------------------------------------
========================page08.gif======================================

*** Diagram: "La-7 N 45213276 (verification trials in GK NII VVS)"

------------------------------------------------------------------------
========================page09.gif======================================

Basic flight-technical data of serial piston engined fighters La-7 1944-1945.

Aircraft, engine, dates of start and end of trials.

1. Flight weight, kg
2. Wing loading, kg/m2
3. Take-off power loading, kg/H.P.
4. Fuel supply, litres
5. Max level speed:
 - at deck level (nominal/WEP), km/h
 - at 1st altitude boundary (nominal/WEP), km/h / m
 - at 2nd altitude boundary, km/h / m
6. Climb time to 5000m (nominal/WEP), min
7. Climb rate at deck level (nominal/WEP), m/s
8. Practical ceiling, m
9. Maximum range, km:
 - at H=1000m
 - at H=3000m
 - at H=5000m
 - at H=7000m
 - comparative fast range
 (H=5000m, TAS=500km/h)
10. Flight duration at max range mode, hour-min:
 - at H=1000m
 - at H=3000m
 - at H=5000m
 - at H=7000m
 - comparative fast range
 (H=5000m, TAS=500km/h)
11. 360deg. turn time, s:
 - at H=1000m
 - at H=5000m
12. Altitude addition per combat turn, m:
 - from H=1000m
 - from H=5000m
13. Take-off run/distance (nom./WEP), m
14. Landing run/distance, m
15. Landing speed, km/h
16. Armament, No. x caliber/ammunition load
17. Geometrical data (sizes):
 - overall length, m
 - wingspan, m
 - wing area, m2
 - wing profile
 - horizontal empennage area, m2
 - vertical empennage area, m2
 - chassis rut (transversal distance between wheels), m

Notes:

1) Serial La-7 No 45210150, plant No21, prod. of July 1944, verification trials
   in GK NII VVS.
2) The same plane after governor RS-2 tuning, standard propeller mounting,
   improvement of fuselage and cowl sealing, improvement of external
   finishing; trials in LII NKAP.
3) Serial La-7 No 45210203, plant No21, prod. of July 1944, verification trials
   in GK NII VVS.
4) Serial La-7 No 38103254, plant No381, trials for fuel consumption in
   GK NII VVS.
5) Serial La-7 No 38105260, plant No381, trials for fuel consumption in
   GK NII VVS.
6) Serial La-7 No 45213276, plant No21, prod. of April 1945, verification trials
   in GK NII VVS.
7) Serial La-7 No 38102663, plant No381, prod. of May 1945, verification trials
   in GK NII VVS.
8) Serial La-7 No 38100869, plant No381, prod. of July 1945, verification trials
   for manoeuverability in GK NII VVS.

[hitech]

F4UDOA, for the last 3 days pyro and I have been working on a new fuel consumption model. So thing will be changing a lot.

HiTech

[Tilt]

wtg HT I think corellating the rpm and throttle to achieve the full range of manifold then matching fuel consumption to that (parabolic with a K factor for different AC) would be great. Plus you could then put rpm based WEP on that calculation and leave the seperate button to the additve WEP.

Then you have  a full fuel model (including WEP which of course will add another problem of limiting its time.........but you guys can do it!)

I edited the column headers to make them clearer.........I hope


Edit columns

man =mm mercury
IAS & TAS = Km/hr
range =km
time = hours - minutes

rpm   man  IAS   TAS   L/km   l/hr   range   time




H=1000m (1st speed of supercharger), fuel supply for level flight - 365 l

2400 1020 575 608 1.020 620 355 0-35
2200 875 530 560 0.800 448 455 0-49
2000 745 480 508 0.655 333 555 1-06
1800 665 430 455 0.585 266 625 1-22
1600 610 385 407 0.560 228 650 1-36
1500 580 360 380 0.550 209 665 1-45

H=3000m (1st speed of supercharger), fuel supply for level flight - 345 l

2400 990 554 644 0.975 628 355 0-33
2200 830 510 588 0.745 438 460 0-47
2000 705 460 532 0.620 330 555 1-03
1800 615 415 480 0.575 276 600 1-15
1600 560 370 428 0.555 238 620 1-27
1500 545 345 400 0.550 220 625 1-34

H=5000m (2nd speed of supercharger), fuel supply for level flight - 325 l

2400 1020 513 658 0.910 600 355 0-32
2200 840 470 604 0.700 423 465 0-46
2000 720 430 554 0.600 333 540 0-58
1800 630 385 496 0.560 278 580 1-10
1600 590 340 440 0.550 242 590 1-20

H=7000m (2nd speed of supercharger), fuel supply for level flight - 300 l

2400 870 454 647 0.735 476 405 0-38
2200 685 415 593 0.570 338 525 0-53
2000 590 380 544 0.500 272 600 1-06
1800 515 340 490 0.460 225 650 1-20
1600 465 300 433 0.450 195 665 1-32

[joeblogs]

Very glad to hear this.

-Blogs

Originally posted by hitech
F4UDOA, for the last 3 days pyro and I have been working on a new fuel consumption model. So thing will be changing a lot.

HiTech

[joeblogs]

This is tricky. As we have learned fuel mixtures depend a lot on carburetor/injector settings. We know what the ideal is, but we don't typically know what the fudge factor is to prevent detonation.

-Blogs

Originally posted by Tilt
wtg HT I think corellating the rpm and throttle to achieve the full range of manifold then matching fuel consumption to that (with a K factor for different AC) would be great. Plus you could then put rpm based WEP on that calculation and leave the seperate button to the additve WEP.

Then you have  a full fuel model (including WEP which of course will add another problem of limiting its time.........but you guys can do it!)

I edited the column headers to make them clearer.........I hope


Edit columns

man =mm mercury
IAS & TAS = Km/hr
range =km
time = hours - minutes

rpm   man  IAS   TAS   L/km   l/hr   range   time




H=1000m (1st speed of supercharger), fuel supply for level flight - 365 l

2400 1020 575 608 1.020 620 355 0-35
2200 875 530 560 0.800 448 455 0-49
2000 745 480 508 0.655 333 555 1-06
1800 665 430 455 0.585 266 625 1-22
1600 610 385 407 0.560 228 650 1-36
1500 580 360 380 0.550 209 665 1-45

H=3000m (1st speed of supercharger), fuel supply for level flight - 345 l

2400 990 554 644 0.975 628 355 0-33
2200 830 510 588 0.745 438 460 0-47
2000 705 460 532 0.620 330 555 1-03
1800 615 415 480 0.575 276 600 1-15
1600 560 370 428 0.555 238 620 1-27
1500 545 345 400 0.550 220 625 1-34

H=5000m (2nd speed of supercharger), fuel supply for level flight - 325 l

2400 1020 513 658 0.910 600 355 0-32
2200 840 470 604 0.700 423 465 0-46
2000 720 430 554 0.600 333 540 0-58
1800 630 385 496 0.560 278 580 1-10
1600 590 340 440 0.550 242 590 1-20

H=7000m (2nd speed of supercharger), fuel supply for level flight - 300 l

2400 870 454 647 0.735 476 405 0-38
2200 685 415 593 0.570 338 525 0-53
2000 590 380 544 0.500 272 600 1-06
1800 515 340 490 0.460 225 650 1-20
1600 465 300 433 0.450 195 665 1-32

[F4UDOA]

HT,

Thanks for listening:aok

I have been studying fuel consumption like a madman for a while now. I have emailed most of my docs to Pyro.

What I am posting now is as much for the comminuty as anything.

Again thanks for being responsive.

BTW, I will probably do one more consumption post on the BF109-G10/K4 and the DB-605ASC just to drive the Luftwabbles crazy.

Just ignore it, if it is old news.

[simshell]

could some one tell me very simple how much was the range at cruise and full power of the LA7 in miles

[Tilt]

Originally posted by simshell
could some one tell me very simple how much was the range at cruise and full power of the LA7 in miles

Rough guide 1 km = 5/8mile

Full power no wep was at 2400 rpm

(eg at just under 10,000 ft @ 2400 rpm with man 990 on 1st stage boost it had a range of approx 222 miles)

You could assume cruise to be about 2000 rpm

(eg at just under 10,000 ft @ 2000 rpm with man 705 on 1st stage boost it had a range of approx 347 miles)

What is referred to as maximum range mode seems to give a range of 390 miles at rpm 1500 man 545 (half power).

However I am also aware that continued running at lowest revs gave concern re plugs oiling and fouling.

[Tilt]

btw page 9 is the translation of the text on some tables..............

I have the tables and for 2 AC the detail ranges are given and the max range and comparative fast ranges are given for three others...........

They vary.................







Serials starting 452 were most probably from Gorky........

Those starting 381 I would speculate were from tblisi as this was the only plant to produce the 3 gun variant later on.

You will note the significant difference in ranges which may be expected across such trials with ex production AC manufactured under mediocre quality control standards.

However it would be prudent to note that 381032534 (subject of more detailed data above). Was at the lower end of the  group tested...........ie its endurance was less than average for the type.

Particularly when compared to 38105260 tested some 5 months later. (also it seems the subject of range tests although we do not know the rpm and manifold  pressures for this later set of figures)

Note the cannon load outs for all these trials.

[joeblogs]

The following is a chart I did a while back based on Tilt's translation of the La-7 flight test data.

Tilt - please correct me if there is something off here.

-blogs

Originally posted by simshell
could some one tell me very simple how much was the range at cruise and full power of the LA7 in miles

[F4UDOA]

WTG JoeB!!

I just saved you chart in my files. Question, where do you see TAS as 378MPH? I see the 357MPH at 3K but I'm not sure where the TAS number came from.

Tilt,

Great stuff once again. Do you have a translated copy of those pages??

[joeblogs]

It should have come from transforming a TAS number from KM to miles, but I did that a year ago. I'll check the program.

-Blogs

Originally posted by F4UDOA
WTG JoeB!!

I just saved you chart in my files. Question, where do you see TAS as 378MPH? I see the 357MPH at 3K but I'm not sure where the TAS number came from.

Tilt,

Great stuff once again. Do you have a translated copy of those pages??