Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: simshell on February 20, 2004, 04:11:25 PM
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iv allways hear how the LA7 should fly alot worse at higher alt but these are just whines on chanl 1
but i do know that the LA7 LA5 were made for mid low alt fights and not high alt
so i ask how did the LA's get worse with alt and how much would they be hurt at say 20k 25k 30k 35k
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No turbocharger for high alt flying
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This is a plane with a two speed, single stage supercharger. It's not going to do great above 20k.
What's more, the gearing was set to allow for maximum HP at reletively low altitudes, which is where most combat ocurred on the Eastern Front.
-Blogs
Originally posted by simshell
iv allways hear how the LA7 should fly alot worse at higher alt but these are just whines on chanl 1
but i do know that the LA7 LA5 were made for mid low alt fights and not high alt
so i ask how did the LA's get worse with alt and how much would they be hurt at say 20k 25k 30k 35k
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I hope this helps. The first one shows the La-5FN/La-7`s M-82FN engine power output vs. altitude. It looses power quickly with altitude.
(http://www.x-plane.org/users/isegrim/M82FNWcurve.jpg)
Naturally this effects climb and speed directly vs. altitude. The Lavockin 5FN and 7 looses climb rate very quickly above 1500m, and speed is not as good as Western planes with good superchargers above 5-6000m.
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Interesting chart, awfully steep power drop off below rated altitude. 100 ps in 1500 m is very high. Plug things into my power calculator comes up with this.
For low blower I have given both maximum MAP & power and power at the 1.36 ATA limit. Ps rounded to nearest 5 hp, Hg to nearest .1 in. Power is in ps, to get hp multiply by .986.
low blower
SL 1.63 ATA, 48.8 in Hg, 1940 ps; 1.36 ATA, 40.6 in Hg, 1615 ps
500 1.60 ATA, 47.9 in Hg, 1910 ps; 1.36 ATA, 40.6 in Hg, 1620 ps
1000 1.57 ATA, 47.0 in Hg, 1880 ps; 1.36 ATA, 40.6 in Hg, 1620 ps
1500 1.54 ATA, 46.2 in Hg, 1850 ps; 1.36 ATA, 40.6 in Hg, 1625 ps
2000 1.52 ATA, 45.3 in Hg, 1820 ps; 1.36 ATA, 40.6 in Hg, 1630 ps
2500 1.49 ATA, 44.5 in Hg, 1790 ps; 1.36 ATA, 40.6 in Hg, 1630 ps
3000 1.46 ATA, 43.7 in Hg, 1760 ps; 1.36 ATA, 40.6 in Hg, 1635 ps
3500 1.43 ATA, 42.9 in Hg, 1730 ps; 1.36 ATA, 40.6 in Hg, 1635 ps
4000 1.41 ATA, 42.1 in Hg, 1700 ps; 1.36 ATA, 40.6 in Hg, 1640 ps
4500 1.38 ATA, 41.3 in Hg, 1675 ps; 1.36 ATA, 40.6 in Hg, 1640 ps
5000 1.36 ATA, 40.6 in Hg, 1645 ps
5500 1.33 ATA, 39.8 in Hg, 1620 ps
6000 1.31 ATA, 39.1 in Hg, 1590 ps
6500 1.28 ATA, 38.4 in Hg, 1565 ps
7000 1.26 ATA, 37.6 in Hg, 1535 ps
7500 1.23 ATA, 36.9 in Hg, 1510 ps
8000 1.21 ATA, 36.2 in Hg, 1485 ps
8500 1.19 ATA, 35.5 in Hg, 1460 ps
9000 1.17 ATA, 34.9 in Hg, 1435 ps
9500 1.14 ATA, 34.2 in Hg, 1410 ps
10000 1.12 ATA, 33.5 in Hg, 1385 ps
cutover to high blower
10500 1.36 ATA, 40.6 in Hg, 1420 ps
11000 1.36 ATA, 40.6 in Hg, 1425 ps
11500 1.36 ATA, 40.6 in Hg, 1425 ps
12000 1.36 ATA, 40.6 in Hg, 1430 ps
12500 1.36 ATA, 40.6 in Hg, 1430 ps
13000 1.36 ATA, 40.6 in Hg, 1435 ps
13500 1.36 ATA, 40.6 in Hg, 1435 ps
14000 1.36 ATA, 40.6 in Hg, 1440 ps
14500 1.36 ATA, 40.6 in Hg, 1440 ps
15000 1.36 ATA, 40.6 in Hg, 1445 ps
155001.33 ATA, 39.8 in Hg, 1420 ps
16000 1.30 ATA, 39.0 in Hg, 1395 ps
16500 1.28 ATA, 38.2 in Hg, 1370 ps
17000 1.25 ATA, 37.4 in Hg, 1345 ps
17500 1.23 ATA, 36.7 in Hg, 1320 ps
18000 1.20 ATA, 35.9 in Hg, 1295 ps
18500 1.18 ATA, 35.2 in Hg, 1270 ps
19000 1.15 ATA, 34.5 in Hg, 1250 ps
19500 1.13 ATA, 33.8 in Hg, 1225 ps
20000 1.11 ATA, 33.1 in Hg, 1200 ps
21000 1.06 ATA, 31.7 in Hg, 1155 ps
22000 1.02 ATA, 30.4 in Hg, 1115 ps
23000 .97 ATA, 29.1 in Hg, 1070 ps
24000 .93 ATA, 27.9 in Hg, 1030 ps
25000 .89 ATA, 26.7 in Hg, 990 ps
26000 .85 ATA, 25.6 in Hg, 950 ps
27000 .82 ATA, 24.5 in Hg, 915 ps
28000 .78 ATA, 23.4 in Hg, 880 ps
29000 .75 ATA, 22.4 in Hg, 845 ps
30000 .71 ATA, 21.4 in Hg, 810 ps