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i never see data that show that La-5FN was almost as fast atthe 109K, or i need thet you explain how many it's almost
Now I believe you are just trolling, instead of wanting any discussion.
Hi,
for example on this page:
Lavochkin fighters
On this page its listed with 573km/h:
http://www.desertstar.co.uk/warbirds/http___www.btinternet.com_~fulltilt_PerformLa5La7.pdf
There is a other comparison graphic floating around here in this forum(maybe even post), where the La5 FN get shown with 575-580km/h sea level.
All this is pretty close to the 109K4 performence with 1850PS, the La7 show the same or even bettwe performence like the like the K4 with 2000PS (sea level).
I have no idea what is the real source for the La datas, actually i never saw a real complete test for any russian plane, just datas, without source and without circunstances how the the datas was produced.
And i would realy like to see such datas, or at least the source where the known datas came from.
Greetings,
Knegel
ok at sea level the max speed of La-5FN it's near of that 109K-4, if the K-4 have not MW. but at 3 km there are around 40 km/h of advantage for K-4.
1350ps was the Ash-82F at the 2nd supercharger stage, so at 5400m(static power, without RAM effect)
The Ash-82FN had 1630PS at 1650m static power, due to the Ram effect at highspeed the rated altitude got shifted upward to around 3000m.
The La5FN speed curve, shown in a russian fighter comparison sheet, display roundabout 620km/h at 3000m, a similar sheet show 650km/h for the la7 at this altiude.
The only known 109K4 DB605DB + MW50 speed curve also show 650km/h at 3000m.
The 109K4 with DB605DC without MW50 was roundabout 5km/h slower, but thats just fluctuation, cause both engines should have the same power output(1850PS sea level, 1900PS at 800m, 1600PS at 6000m, all static power).
This test curves are all made with the "Dünnbrettschraube "(new propeller), the seriel propeller made 10km/h less.
The DB605D test never felt to my Eye´s, although i was on Kurfürsts page many times.
Interesting to see is that the DB engine had a 1000m higher rated altitude with MW50, so somehow the presure must have been smaler, this would explain the discrepancy.
Still the La5FN and La7 different need a claricication, 35-40km/h cant come from some simple cleanups.
Somewhere i did read that there was a Ash82FN and FNU engines, maybe thats the cause?
The E for sure, probably the F, might be the G. But what does-it change for the 109's high Cd square-shaped canopy?What 109 got tested in the wind tunnel?
And one of the highest Cd = 0.036 for in-line engeened planes. From Hoerner studies.The 109 had one of the smalest front surfaces of all WWII planes, Cd is just a factor that need to get multiplicated with this area.
For most canopys I don't know, at least Yakovlev and Bell teams made their jobs, Masserschmitt' s one didn't.That most canophys could have been better in a aerodynamical way is well known, but plating glas is mainly flat, as such must canophys with plating glas had a not that good Cd, but still its just the area of the very tiny canopy.
Mainly from the NII-VVS, LII-NKAP, sometimes from experimental operative units, TsAGI reaserch center had it's flying team too.btw, i still dont saw any WWII tests of the Yak´s, so where does the datas comes from??
.They stand in the same discrepancy to other 109 tests like some Yak datas also wont fit to each other
Usually in the world of aeronautics, yes!Would be interesting if this datas are calculated or tested and if they are corrected to standard athmosphair etc.
And you know what, all the La-5F, La-5FN, La-7 used in 1944 the same Shvetsov M-82FN engine…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.
40km/h, thats like a 109G-2 with and without 250kg bombs.
Difficult to say, without aerodynamical knowledge, what should be rubbish and what not. It takes an experienced graduated engeneer.he 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) .
Here for instance, a complaint report with an unsatisfactory La-7, from the NII-VVSStill, also for this La5/7 datas i never saw a test.
And one of the highest Cd = 0.036 for in-line engeened planes. From Hoerner studies.
Regards
.But basically Cd is a meaningless figure, its not even a measure of aerodynamic cleaness. Its always related to wing area, not the entire wetted or frontal area. Basically aircraft with smaller wing area will get higher Cds because of this, since the wing only creates a portion of the drag (say 30-50%), but you compare 100% of the drag to that figure
Hoerner's figures are estimates, based on some very rough estimates of speed, thrust and propeller effiency. They are in disagreement with the actual Messerschmitt papers and polars I have, which state a Cd = 0.023 for the 109F/G - that's pretty avarage BTW.
Sea Level:
Bf109G-1 525km/h 1310PS
Yak-1/9 530km/h 1210PS
Hoerner's figures are estimates, based on some very rough estimates of speed, thrust and propeller effiency. They are in disagreement with the actual Messerschmitt papers and polars I have, which state a Cd = 0.023 for the 109F/G - that's pretty avarage BTW.
But basically Cd is a meaningless figure, its not even a measure of aerodynamic cleaness. Its always related to wing area, not the entire wetted or frontal area. Basically aircraft with smaller wing area will get higher Cds because of this, since the wing only creates a portion of the drag (say 30-50%), but you compare 100% of the drag to that figure.
Hoerner's figures are estimates, based on some very rough estimates of speed, thrust and propeller effiency. They are in disagreement with the actual Messerschmitt papers and polars I have, which state a Cd = 0.023 for the 109F/G - that's pretty avarage BTW.
Thanks, Kurfürst.
I am quite puzzled, as where the difference comes from. Hoerner's subject was apparently G-6, the most draggy submodel, but still