Aces High Bulletin Board
General Forums => Aces High General Discussion => Topic started by: Tilt on June 18, 2003, 10:42:46 AM
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tail wheel is a free castor type
(http://www.btinternet.com/~fulltilt/la7frontgear.GIF)
WWII models did not have the leather sock pictured here
(http://www.tilt.clara.net/White77/Rearwhl.jpg)
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(http://www.tilt.clara.net/White77/prtslat.jpg)
and fully out
(http://www.tilt.clara.net/White77/prtslatx.jpg)
Oh and if you look along the wing you see a little red pin sticking out................. thats the gear down indicator .......one on each side........as well as the onboard indicator light
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(http://www.tilt.clara.net/White77/instcen.jpg)
see how high it is ......compared to AH it fills the forward armoured screen.
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(http://www.tilt.clara.net/White77/armglass.jpg)
no metal bars across the middle.........just a thicker bead of glass.
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nice work tilt
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This 3 tank AC had a fuel selector switch
It could only trim rudder and elevator from inside the cockpit
It has a flap indicator (fully variable not stepped)
Guns could be manually primed and cleared.
It had no ammo level indicator.
It had a radio compass (course indicator) and a magnetic compass but no gyro compass.
There was a cockpit light switch.
With Hydraulics failed the gear could still be lowered by air but the flaps were out of action.
It did not have individual control of the wheel brakes (but its airfields did have folk who could grab a wing and push it)
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Ya nicely done.:)
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and this
(http://www.tilt.clara.net/pics/PAGE1-18.JPG)
I dont understand it but can tell you it is the out put from a series of wind tunnel tests on an La7
L is the angle the AC was placed at to the wind tunnel flow AOA? (i have a series of photographs showing this)
What Cx and Cy are I am not sure but I suspect Cy has something to do with lift and that may mean Cx has someing to do with drag both of which could be discerned from load cells on the support frames............
Air velocity is constant for all tests
There are some other ancillary graphs with it that I do not understand either.
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Tilt,
I think that is a Cl max graph. Looks like about 1.4 which is right with many WW2 fighters IMHO.
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Originally posted by F4UDOA
Tilt,
I think that is a Cl max graph. Looks like about 1.4 which is right with many WW2 fighters IMHO.
What ever that means .............. thanks:)
Coefficient of lift?
So what is Cx?
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Originally posted by Tilt
Guns could be manually primed and cleared.
It had no ammo level indicator.
I would guess that if the pilot could manually prime / clear the guns, he could manually check approximate ammo remaining as well.
Originally posted by Tilt
With Hydraulics failed the gear could still be lowered by air but the flaps were out of action.
I hope that HTC models hydraulic systems in all A/C that had them and makes them a damageable system. It would add another level of realism into the game.
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Why don't we begin by fixing the inaccurate endurance of this plane?
-Blogs
Originally posted by Tilt
tail wheel is a free castor type
(http://www.btinternet.com/~fulltilt/la7frontgear.GIF)
WWII models did not have the leather sock pictured here
(http://www.tilt.clara.net/White77/Rearwhl.jpg)
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Originally posted by joeblogs
Why don't we begin by fixing the inaccurate endurance of this plane?
-Blogs
I suggest you refer to innomminates tests.... its not so durable here............ even if it is difficult to hit........
actually it was a monocoque (all glued together)and structuraly very durable........... it had very few "critical points" structurally
the wings were as thin as a Spitfires yet could with stand more G
Fuel tanks were self sealing and had inert gas from the exhaust sytem pumped into them to quench flame.
Its most vulnerable external machine part was the oil cooler............
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Endurance and durable are two different words.
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what was their purpose? the leading edge slats? that's something pretty new to my conceptions of planes. trailing edge i see see.... leading edge and the way they're deployed as you showed... ??
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They allowed for higher AoA (by "helping" the air flow over the leading edge of the wing), and ensured laminar airflow over the ailerons even if the inner wings (without slats) were stalled, allowing roll control at very low speeds. Most energy fighters had them, 109's 190's and the like.
EDIT: They could be a mixed blessing though as I remember reading about the 109G6 pilots having problems with the slats suddenly deploying during high-G turns throwing their aim off. I don't know if that is modelled in AH, but sometimes I get jerky reactions in turns like that in the 109 and 110.
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Originally posted by Shane
what was their purpose? the leading edge slats? that's something pretty new to my conceptions of planes. trailing edge i see see.... leading edge and the way they're deployed as you showed... ??
The purpose is to enable an increased AoA at slow air speeds and so lower the natural stall point of that part of the wing...
I believe the above graph shows this to some extent.
They (the slats) are balanced and sucked into position by the negative pressure that occurrs at this part of the wing at slow speeds with increased AoA. On an La7 this was at 200 > 220 kph..optimum climb figures are given at 260kph descending to 180 kph above 9000 metres the slats deploying at about 7000>8000 metres.
They are in fact auto slots which allow high pressure air from under the wing to "clean up" dirty air (due to a high AoA) ontop of the wing .
They carry some disadvantages with their advantages
a) the proper landing speed of an La7 should be nearer 80 mph than the 100+ we use now........ 80 mph is impossible in AH now (or at least very very difficult) At 100 + the infamous gear bounce would have catapulted the la7 back into the air...........at 80 with slots modelled you will be very nose up and totally blind.
b)they reduce drag at high AoA and when landing you want drag.
c)when one is damaged you have two wings which exhibit different lift during landing.
d) the onset of subsequent stall is very sudden.
How may they effect AH's La7?
well HT will decide but some speculation would be interesting
They should not change climb rate or top speed.
Optimum climb rate figures upto approx 7500 metres are at IAS above 220kph so slats are not deployed.
Obviously at top speed they are not deployed.
They may lower the stall speed both flat stall and wing dipped high speed stall.
Slow high yo yo's may require a Js correction as the lower wing slot deploys trying to lift it against the attitude you have set.
They give AH the option of usuing the la slats as the only source of stall onset warning. There is no stall buzzer in an La and the wing is not twisted like a spit to give stall flutter over the wing root.
With the stall speed lowered we may find minimum turn radius also lowered.......but not turn rate.
Add this to no independent wheel brakes, horrendous gear bounce, true castor tail wheel charcturistics, rapid stall recovery and modified torque effects in such a short high powered (low drag) AC and I think we will approach exactly what the La 7 was.
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The effects of the leading edge slats are modelled. It's just not visually represented.
At least, that is AFAIK.
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Very nice Tilt :)
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That's Kozhedub's La-7?
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Originally posted by Dowding
That's Kozhedub's La-7?
No its white 77 at Prague (kbelby) Museum.
more pics (http://www.tilt.clara.net/White77/index.html)
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As noted above the ailerons could not be trimed from the cockpit (merelt balanced by trim tabs on the ground)
However for the damage model it should also be noted that only the port elevator had trim adjustment (which was adjustable from cockpit)
Hence when the port elevator is lost so is elevator trim capability. (manual or "combat")
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This is the results of range tests on an La 7........
Note the variation of manifold pressure with engine revs........ I believe that the correlation between revs and power should some how be duplicted not only to enable a true range model but to generate the linked WEP model.
None of these tests Ivoke a WEP setting ( @2500rpm)
The column titles from left to right are...
RPM, Supercharger pressure, IAS Km/hr, TAS km/hr, fuel consumption- lit/Km, lit/hr, range till empty km, time til empty mins.
The 4 blocks of data are at 1000, 3000, 5000, 7000 m alt
@5000 (4500) the engine is running at the upper (of 2)supercharger speed.
(http://www.tilt.clara.net/pics/PAGE02.GIF)
here the data is summarised with other considerations such as fuel spent warming up,take off, climb to cruise alt, decent, landing etc
(http://www.tilt.clara.net/pics/PAGE03.GIF)
I have full English translations but thought the original Russian may be a bit more authentic.
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You have seen how the manifold pressure (and fuel consumption )changed with rpm.
here are pages 122 and 123 from the la7 pilots/maintenance book.
You will note that WEP lasts 10 minutes at @ 2500 rpm and increases boost from 1000 mm to 1200mm
(http://www.tilt.clara.net/pics/page122.gif)
(http://www.tilt.clara.net/pics/page123.gif)
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Note it turns to the right quicker than it does to the left by 1 sec in 18.5 >19.5 @ 1000m, and in 26>27 secs @ 5000 metres.
Speeds are 340 and 300 km/hr IAS respectively.
Also the landing speed with full flaps and near full weight (240 Kg light.) is 135km/hr over a 25 metre high object.
(http://www.tilt.clara.net/pics/PAGE05.GIF)
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Trials on the post GPW 3 gun version would seem to contradict the earlier trials above................... however look at the different radii and bank angles used.
(http://www.tilt.clara.net/pics/PAGE06.GIF)
Titles for the turn performance table are left to right
Alt, direction(left/right), IAS km/hr, time per turn sec, turn radius metres, bank angle degrees.
The report suggests that the Yak 3 in comparison sufferred more in right/left hand differential turn rates than the La 7 although IMO the actaul difference was less than the probable experimental tollerance that should be applied.
Also all these tests have been done at circa 300Km/hr IAS (186mph) it does not indicate if that is the optimum turning speed.
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Thanks for posting this.
-Blogs
Originally posted by Tilt
This is the results of range tests on an La 7........
Note the variation of manifold pressure with engine revs........ I believe that the correlation between revs and power should some how be duplicted not only to enable a true range model but to generate the linked WEP model.
None of these tests Ivoke a WEP setting ( @2500rpm)
The column titles from left to right are...
RPM, Supercharger pressure, IAS Km/hr, TAS km/hr, fuel consumption- lit/Km, lit/hr, range till empty km, time til empty mins.
The 4 blocks of data are at 1000, 3000, 5000, 7000 m alt
@5000 (4500) the engine is running at the upper (of 2)supercharger speed.
here the data is summarised with other considerations such as fuel spent warming up,take off, climb to cruise alt, decent, landing etc
I have full English translations but thought the original Russian may be a bit more authentic.
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Originally posted by Tilt
I suggest you refer to innomminates tests.... its not so durable here............ even if it is difficult to hit........
actually it was a monocoque (all glued together)and structuraly very durable........... it had very few "critical points" structurally
I believe Joeblogs was referring to the airplane's flying time available, sometimes referred to as range, other times as ENDURANCE. ;)
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Does this all mean they will finally perk the damn thing?
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Originally posted by MrWimpy
I believe Joeblogs was referring to the airplanes flying time available, sometimes referred to as range, other times as ENDURANCE. ;-)
Thanks.... I had not realised....I work with the Oxford and have little knowledge of Websters:)
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Yes I was referring to how long you can keep the plane in the air. I am not aware of any issues with the modeling of the plane's resistence to cannon or machine gun fire.
-Blogs
Originally posted by MrWimpy
I believe Joeblogs was referring to the airplanes flying time available, sometimes referred to as range, other times as ENDURANCE. ;-)
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Originally posted by Tilt
Thanks.... I had not realised....I work with the Oxford and have little knowledge of Websters:)
Ahhh, ok. :)
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Tilt,
Could you post the english version of those docs. That is some amazing stuff you have there.
Joe B. Can you make heads or tails of it?
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Originally posted by F4UDOA
Tilt,
Could you post the english version of those docs.
http://www.tilt.clara.net/pics/AKT_LA7.rtf
Ther is sime additional stuff at the bottom that refers to charts/graphs/the list of test AC