Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: VWE on January 16, 2005, 05:16:07 PM
-
I upped a 152 in the CT last night and seeing that I owned the skies I did a little testing. At 41,010 feet the 152 should do 472 mph with wep, I let wep go till it ran out and as fast as it got was 451 mph. I'm sure this has an effect on it at lower altitudes too, I filmed my test incase someone would like to see it. This plane feels sluggish, someone should look at their data again on this one.
-
Heh.. the 152's acceleration is so awful that you might have not even topped out with full WEP.
Try diving from above that height and see if it'll hold 470.
-
Originally posted by VWE
I upped a 152 in the CT last night and seeing that I owned the skies I did a little testing. At 41,010 feet the 152 should do 472 mph with wep, I let wep go till it ran out and as fast as it got was 451 mph. I'm sure this has an effect on it at lower altitudes too, I filmed my test incase someone would like to see it. This plane feels sluggish, someone should look at their data again on this one.
Maximum speed 332mph at sea level ( 350mph with MW 50 ), 465mph at 29,530ft. ( with
MW 50 ), 472mph at 41,010ft. ( with GM 1 ), 311mph cruising speed
at 22,965ft.
we dont have MW50 or GM1 so speeds might not match. our
WEP might simulate MW50 though.
-
Originally posted by whels
we dont have MW50 or GM1
Are you sure?
-
Above FTH MW-50 isn't necessary to maintain maximum boost, the supercharger at above FTH is already losing power. All MW-50 does is cool the charge so that below FTH the airplane can run max power (all though limited) with out risk of detonation. Above FTH MW-50 still cools the charge but its not needed to prevent detonation.
Its not majic juice or something that 'burnt' like GM-1.
GM-1 has limited usefulness in that for the Ta-152 it could only be operated for short periods above 9000m (29527 mph).
I didn't know what 'wep' means for the TA-152 in AH. But they did pull down the first 152 chart and replace it with one that didn't show speed and climb to 40000ft. I believe if you search for a post or 2 by wilbus you will find those old threads.
In FB/AEP/PF the the Ta-152 has both MW-50 and GM-1, MW-50 for about 6000m and below and GM-1 for above 9000m. With GM-1 the Ta-152 is untouchable.
-
Pyro did say back when they were kicking this dead horse with charts and official scheisse about the Ta-152 pyro mentioned it had Gm1 and MW50 simulated . It was concluded that most speeds matched with the H-0 than the H-1.
-
I'm pretty sure Wilbus already caught this yet nothing has been done about it.
-
wotan, can you explain what is GM-1 system\fuel\thingi and how did it work?
-
Originally posted by Wotan
GM-1 has limited usefulness in that for the Ta-152 it could only be operated for short periods above 9000m (29527 mph).
Me think we need a bigger arena :D
-
Originally posted by Flyboy
wotan, can you explain what is GM-1 system\fuel\thingi and how did it work?
Nitrous oxide injection.
You can get kits for your street car.
-
Flight testing offline, setting fuel burn to 0.1 (10.0 between to burn it off):
with full fuel and no ammo (diving down then see which speed it can hold):
41010 feet 450mph with wep
29520 feet 452mph with wep
with 30gallons of fuel left, no ammo:
29520 feet 456mph with wep
120 feet 363mph with wep
at least on my tests. thats the version in ah 2.06
cya schutt
-
FYI:
In FB/AEP/PF the Ta-152H-1 does
323mph @ SL @ 100% Power
419mph @ 31988ft @ 100% power
370mph @ SL @ maximum power (MW-50 + 110% throttle)
470mph @ 28707ft @ maximum power (GM-1 + 100% throttle)
at least according to IL2 compare.
-
I wouldn't care except that the TA-152 has a pretty heavy perk price. Way more than it is worth in performance.
Now a 370 mph 152 at sea level and 470 mph at 28K might be worth the perk cost.
-
Hi Flyboy,
>wotan, can you explain what is GM-1 system\fuel\thingi and how did it work?
GM-1 was the German WW2 code-name for N2O (nitrous oxide, or laughing gas).
N2O can be added to the fuel-air mixture of an internal combustion engine. In the compression cycle, it's broken up into its components, releasing oxygen that can be used for combustion.
As the challenge of high-altitude flight mainly consists of getting enough oxygen into the cylinder to maintain adequate power - which due to the decreasing air density becomes more and more difficult at altitude - N2O equates to extra power.
In fact, N2O was injected into the supercharger in liquid form through small jets, and each jet gave a constant power boost when employed. Depending on the type, you might have a 120 HP jet and a 240 HP jet, which of course added 360 HP when used in combination.
That's the resason N2O was available in steps - you couldn't add 360 HP to an engine that was already running at close to full power, or the resulting forces would destroy vital parts of the engine.
This is the main reason N2O was preferred over pure oxygen, which could be (and experimentall, was) used for the same purpose - it just gave too much power.
The nitrogen share of the nitrous oxide has a benefit, too, since it absorbs some energy on being broken up in the cylinder, controlling the detonation and allowing higher pressure.
Since N2O is injected into the supercharger as a liquid, it also gives a charge cooling effect on evaporation (cooler air means more oxygen in the same volume).
Initially, N2O was stored under high pressure to keep it liquid (laughing gas, after all, is a gas under standard conditions), but that meant the N2O vessels blew up like a bomb on being hit, so from 1941/42 on it was stored at very low temperature in an insulated tank that kept the content at less than -90 °C for as long as the sortie lasted.
(It was used by bombers like the Ju 88 and by reconnaissance planes like the Ju 86 as well, so that could be quite a long time. For fighters at readiness on the ground in the hot summer sun, though, the insulation would not have sufficed and the N2O would have begun to boil out through the safety valve after a while.)
For comparison: 0.1 kg/s of N2O injection gave extra 300 - 400 HP, virtually out of nothing.
The only drawbacks were the weight of the system (which also included compressed air bottles to force the N2O out of the insulated tank), and - more importantly - the high rate of consumption. If 0.1 kg/s gave 350 HP, that made for a specific fuel consumption of 1000 g/HPh, which compares very unfavourably to the DB601A's normal 220 g/HPh at high power :-)
So, N2O was bad for range, but great for high-altitude power.
Oh, by the way, someone mentioned that N2O was to be used for short bursts only. According to what I have read, it could be used as long as it was available and in fact short bursts were to be avoided as filling and emptying the N2O lines took some time and created some engine management difficulties.
Regards,
Henning (HoHun)
-
Originally posted by HoHun
GM-1 was the German WW2 code-name for N2O (nitrous oxide, or laughing gas).
That's certainly the best explanation of the process that I've seen, HoHun, thanks.
- oldman
-
thnks hohun that really clear things up! :)
now... to raid the local dentist and install N2O to the buggy :D
-
Oh, by the way, someone mentioned that N2O was to be used for short bursts only. According to what I have read, it could be used as long as it was available and in fact short bursts were to be avoided as filling and emptying the N2O lines took some time and created some engine management difficulties.
That is correct. It took up to 3 minutes for the lines to clear and the LNOX to reach the engine. LNOX would evaporate in the lines if it was not turned on and running.
Once it got going it was left on until the tank went dry or it was no longer needed.
Crumpp
-
I read that GM-1 equipped Bf109E7 gained some 80km/h at high alt over standard power..
-
Crumpp is HoHun?
-
Hi Oldman,
>That's certainly the best explanation of the process that I've seen, HoHun, thanks.
Glad you found it interesting :-)
To add to its usefulness, I should state the main sources: "Die deutsche Luftfahrt - Flugmotoren und Strahltriebwerke" by Kyrill von Gersdorff, Kurt Grasmann, Helmut Schuber and (might seem a bit off topic at first) "Motorcycle Turbocharging, Supercharging and Nitrous Oxide" by Joe Haile.
Regards,
Henning (HoHun)
-
Hi Flyboy,
>now... to raid the local dentist and install N2O to the buggy :D
LOL!
Be careful with the opposite direction though: Industrial N2O is contaminated with other gases and not suitable for human consumption! =8-O
(It's the same with oxygen, but unlike oxygen, industrial laughing gas is abused occasionally by clueless kids for its reportedly intoxicating effect.)
Regards,
Henning (HoHun)
-
Hi Grünherz,
>I read that GM-1 equipped Bf109E7 gained some 80km/h at high alt over standard power..
Radinger/Schick provide a figure of a 100 km/h gain at 8 km, from 250 - 280 PS at 0.1 kg/s. The lower figure than the 300 - 400 PS quoted above probably is the result of using pressurized instead of cooled N2O. (von Gersdorff et al. confirm the figures.)
For the E-7/NZ, 60 g/s, 100 g/s and 150 g/s were available, with the 60 g/s being available from 6.5 km up.
Unfortunatelly, the Emil delivery table in Radinger/Schick is confused just where the E-7/NZ comes into play. It seems 311 Emils were delivered by the factories producing E-7/NZ during the time the E-7/NZ was produced, but some (most?) of them were standard E-7/N models. And I just don't understand the table :-(
Additonally, the GM-1 gear could be retro-fitted, but only at one shop in Dortmund. The factory-fitted E-7/NZ apparently entered production in March 1941.
Of the Emil with DB601N, 496 were produced until 31.10.1940. The number is from a schedule, but updated on 1.11.1940 so it's semi-retrospective. Except for Fieseler, who were behind the production curve, the factories apparently met the orders fairly well. Fieseler was slow to ramp up production, so the 135 E-7/N they supposedly contributed to the 496 total might be a bit suspect.
The first DB601N-equipped Emils were actually conversions of existing E-4 airframes, arriving at the channel on 21.7.1940 with II./JG26. Apparently, they were the only group to use the DB601N in the Battle of Britain, though the above production totals look a bit contradictory there. Since the Technisches Amt had originally planned the DB601N for the Zerstörers primarily until hurriedly changing priorities when the Bf 110 proved to be a lousy escort fighter, I'd even say the entire production totals are suspect. On the other hand, more than 1000 DB601N engines were produced in 1940, and they must have gone mainly into the Emil. Oh well :-(
Regards,
Henning (HoHun)
-
Well too bad it aint working in our 152, cause it needs something.
-
100Km/h at 8KM, which is like 60mph at 25K feet. Not bad, heck it's amazing..
Would this have made the E7 a 400mph plane in 1940?
-
Hi Grünherz,
>100Km/h at 8KM, which is like 60mph at 25K feet. Not bad, heck it's amazing..
That's why GM-1 was so attractive :-)
But the effect on climb rate was actually more important than on speed. For the Emil, I'd expect a gain of perhaps 8 m/s from full GM-1 usage (estimated by throwing darts at a phone book ;-), which could be activated at the flip of a switch when you had reached service ceiling (0.5 m/s).
The Ju 86R got up to 15 km pressure altitude in an experimental flight using GM-1. Flying a propeller aircraft, that's about as close to astronaut wings as you're going to get ;-)
>Would this have made the E7 a 400mph plane in 1940?
Hm, I'd say it that seems possible (early 1941, actually). Not in the same way like the 400 mph aircraft of later days, though, more like an aircraft with a high-altitude capable turbo-supercharger - "normal" performance at medium altitudes, but it just won't slow down while flying higher and higher.
Regards,
Henning (HoHun)
-
Originally posted by VWE
I upped a 152 in the CT last night and seeing that I owned the skies I did a little testing. At 41,010 feet the 152 should do 472 mph with wep,
I see you guys are back to flying low in the CT.
:rofl
-
HoHun,
The other amazing thing about the Ju-86P and R was they were powered by diesel engines!
63tb
The Ju 86P was produced in two versions, the Ju 86P-1 high-altitude bomber carrying 4 550-lb bombs or 16 110-lb bombs and the Ju 86P-2 high-altitude reconnaissance aircraft equipped with three cameras. No defensive armament was provided, since it was assumed by the Luftwaffe that the aircraft would be completely immune to interception by enemy fighters. During 1940 and 1941, numerous bombing and reconnaissance missions were flown over Britain, the Ju 86P aircraft indeed proving to be immune from interception by RAF fighters. The Ju 86P aircraft also flew some clandestine reconnaissance missions over the Soviet Union in preparation for the June 22, 1941 assault. Some Ju 86Ps were operated in the Mediterranean theater, and flew unmolested numerous times over Egypt. However, the Ju 86P eventually met its match in the form of a specially-stripped version of the Spitfire V evolved by the British to meet the high-altitude threat. The first successful interception of a Ju 86P was on August 24, 1942, when a Spitfire V caught one of these aircraft over Egypt at an altitude of 42,000 feet and forced it to crash into the Mediterranean. In response to this new threat, Luftwaffe personnel hastily fitted a remotely-controlled MG 17 machine gun fixed to fire aft from the rear fuselage. However, a couple more Ju 86P-2s were soon lost to these modified Spitfires. Since the operation of the Ju 86P over enemy territory was becoming increasingly hazardous to the health of its aircrews, the type was shortly thereafter withdrawn from operational service.
In an attempt to improve the chances of the reconnaissance Ju 86 surviving over enemy territory, the Ju 86R series was evolved. An even higher-aspect ratio wing was fitted, having a span of 104 ft 11 3/4 in. A pair of Jumo 207B-3 engines were fitted, each offering 1000 hp for takeoff. The engines were provided with GM-1 boost (nitrous oxide injected into the supercharger) for use above the rated altitude of the engine. Two versions were proposed, the Ju 86R-1 high-altitude reconnaissance aircraft and the Ju 86R-2 high- altitude bomber. A few existing Ju 86Ps were converted to Ju 86R configuration, and tests showed that an altitude of 47,250 feet could be reached and maintained. A few operational missions were flown by the Ju 86R, but the type was eventually taken out of service by July 1944.
Source:
The Warplanes of the Third Reich, William Green
-
Hi 63tb,
>The other amazing thing about the Ju-86P and R was they were powered by diesel engines!
Roger that! :-)
I've seen quite a few Jumo 205 survivors, every technical museum in Germany seems to have one though they weren't produced in great numbers. I guess they were kept for their jaw-dropping qualities ;-)
Have you ever seen one of them? One crankshaft at the bottom, another one on top, pistons going into the cylinder from both ends, aspiration through the cylinder walls and direct fuel injection. The Jumo 207 even had a turbo-supercharger.
Junkers had actually build large, slow running stationary engines for quite a while (steam-engine sized :-) before miniaturizing them for aviation applications in 1928.
The Jumo 205 had a ca. 30% advantage in specific fuel consumption compared to the contemporary Jumo gasoline engines, and this kind of efficiency made them great for economic long-range flights.
Regards,
Henning (HoHun)
-
Jumo 205
(http://www.stobbe.dk/technical_literature/combustion_engines/junker/images/jumo205.jpg)
(http://www.rafmuseum.org.uk/cosford/collections/engines/images/jumo205diesel.jpg)
(http://www.histomobile.com/histomob/internet/techniqu/120-2.jpg)
(http://www.histomobile.com/histomob/internet/techniqu/120-3.jpg)
Jumo 205 with mechanical driven supercharger
* Type: To-stroke supercharged compression ignition
* Cylinders: 6 with 12 opposed piston
* Valve arrangement:
* Bore and Stroke: 105 x twice 160
* Swept volume: 16.6 litre
* Compression ratio:
* Max revolution: 2800
* Power range: 647 kW
* Brake specific fuel consumption (lb/hp/h):
* BMEP: 8.4 Bar
* Weight, kg 600
Jumo 207 experimental from 1944 with mechanical driven supercharger, turbocharger, charge cooling
* Type: To-stroke supercharged compression ignition
* Cylinders: 6 with 12 opposed piston
* Valve arrangement:
* Bore and Stroke: 105 x twice 160
* Swept volume: 16.6 litre
* Compression ratio:
* Max revolution: 3200
* Power range: 1324 kW
* Brake specific fuel consumption (lb/hp/h): 0.32
* BMEP: 15 Bar
* Weight, kg 880
-
Hohun, Milo,
How tall was that engine? Wonder why they didn't mount the prop shaft in the middle. That would have made it a bit easier to blend into the wing. Did it run on regular diesel fuel? I thought that diesel fuel was tough to use in very cold conditions, and it's plenty cold at 40,000 feet!
63tb
-
63tb, if you are in the UK the RAF Museum has one.
As for the questions, no idea.;)
................
For your reading enjoyment:
http://www.enginehistory.org/diesels.htm
The chapter on the Jumo is not ready though.
-
Diesel at very high alts?
NO.
When you're only in -20 C, and want to stay out of trouble, it's not exactly Diesel any more, - being mixed to perhaps 20%.
At -50, you won't even pour Diesel any more, so, I guess it must have been some cocktail.
UNLESS...you keep the fuel and all the oil lines warm, which is quite an effort.
Not done on Diesel engines today, - the Diesel just gets mixed.
-
Originally posted by MOSQ
I wouldn't care except that the TA-152 has a pretty heavy perk price. Way more than it is worth in performance.
Now a 370 mph 152 at sea level and 470 mph at 28K might be worth the perk cost.
Even in early AH2 days when 152 was free, people still didnt use it hardly at all.
-
Originally posted by Angus
Diesel at very high alts?
NO.
When you're only in -20 C, and want to stay out of trouble, it's not exactly Diesel any more, - being mixed to perhaps 20%.
At -50, you won't even pour Diesel any more, so, I guess it must have been some cocktail.
UNLESS...you keep the fuel and all the oil lines warm, which is quite an effort.
Not done on Diesel engines today, - the Diesel just gets mixed.
You simply pre-heat the fuel with the exhaust. Guess what fuel most military vehicles run on? How cold is it in Finnmark and Siberia? ;)
-
It's well known the AH Ta-152 is a bull with no danglin' maracas . :D
-
Originally posted by dedalos
I see you guys are back to flying low in the CT.
Didn't do him any good, he still had to come down low to kill me.
-oldman
-
If I'm in the CT all alone and I auger... does anyone else know about it?
-
Originally posted by VWE
If I'm in the CT all alone and I auger... does anyone else know about it?
One might inquire: Why should you care?
I augur frequently, to even the sides, to get airborne more quickly, to avoid the boredom of flying all the way back home to do that ugly landing routine. Hopefully no one hears this.
- oldman
-
Originally posted by GScholz
You simply pre-heat the fuel with the exhaust. Guess what fuel most military vehicles run on? How cold is it in Finnmark and Siberia? ;)
Or you route some coolant lines through the fuel tanks like on an automatic transmission car which runs a line to the radiator.
-
Don't see the point of the 152 - even at 25k plus it's a hog and an expensive hog at that.
Bring on the D12 or D13 any day.....