Fw-187 could have been German P-51?
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DonL
Banned
In german it called "schubsteigernde Strahldüsen", which was part of the exhaust system.
Simply translated exhaust thrust.
Simply translated exhaust thrust.
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Okay - I read it that 210D was not equipped with ejector exhaust stacks, while the 210G was. Looking at the pictures, the stacks of the 210G equipped Falke were similar to the ones used at Bf-109E and further, ie. on DB-601/605 engines.
The ram effect was a 'property' of intake system.
The ram effect was a 'property' of intake system.
Shortround6
Major General
Both Ram and exhaust thrust are dependent on forward speed. Both are much less at climbing speed or speeds after one or more hard maneuvers than at straight line max level speed.
More properly while the exhaust thrust may be the same the thrust horsepower is less at low speed because of the poor efficiency (matching of exhaust stream speed to forward speed of the plane).
This is the reason engine makers seldom give figures for either RAM or exhaust thrust/power. The first depends on both the intake ducting before the actual engine intake and the forward speed of the aircraft and the second depends on both the forward speed and altitude of the aircraft. Higher altitude means lower atmospheric pressure and thus high exhaust gas velocity.
More properly while the exhaust thrust may be the same the thrust horsepower is less at low speed because of the poor efficiency (matching of exhaust stream speed to forward speed of the plane).
This is the reason engine makers seldom give figures for either RAM or exhaust thrust/power. The first depends on both the intake ducting before the actual engine intake and the forward speed of the aircraft and the second depends on both the forward speed and altitude of the aircraft. Higher altitude means lower atmospheric pressure and thus high exhaust gas velocity.
DonL
Banned
Thanks SR6 for the explanation.
For me the introduction of the exhaust thrust next to the two speed supercharger of the Jumo 210G was the main reason of the performance "explosion" of the FW 187 V4. The V4 was 1050 kg heavier then the V1/V2, but was about 40 km/h faster with "near the same" nominal power output (Jumo 210D to Jumo 210G), then the single seat version, with much better altitude performance through the two speed supercharger and exhaust thrust.
For me the introduction of the exhaust thrust next to the two speed supercharger of the Jumo 210G was the main reason of the performance "explosion" of the FW 187 V4. The V4 was 1050 kg heavier then the V1/V2, but was about 40 km/h faster with "near the same" nominal power output (Jumo 210D to Jumo 210G), then the single seat version, with much better altitude performance through the two speed supercharger and exhaust thrust.
Maybe someone might tell what variant of the Jumo 210 is depicted here (don't be intimidated with cyrilic letters, the numbers are self-explaining. Note the different lines for the power for different airspeeds (300, 400 and 500 km/h), along for the 'static' engine.
The Jumo 210D/E supercharger was two-speed as well, this engine type could be (and was) retrofitted with ejector exhausts.
The 210 B/C used a single-speed supercharger.
If Tomo's graph is from the 210G it just had 10-15 PS more take-off power than the D but it had about 30-40 PS more at ~700m higher altitude.
The 210 B/C used a single-speed supercharger.
If Tomo's graph is from the 210G it just had 10-15 PS more take-off power than the D but it had about 30-40 PS more at ~700m higher altitude.
wuzak
Captain
Evaporative cooling systems do not have to be total loss, as was teh case in the Me 209 V1.
Many of the Schneider Trophy racers used closed circuit evaporative cooling systems.
Take the MC.72, for example:
The copper coloured bits on the airframe (ie not painted red) are for cooling - most of them are condensers for the engine cooling system, though I believe the area around the nose is for oil cooling.
The condensers are there to convert steam back into liquid form. The liquid coolant having converted to steam after leaving the engine.
On the Fw 187-V5 it may be that the small radiator is a small condenser to compensate for a lack of surface area on the airframe, or simply a radiator used to further cool the re-liquified coolant.
If the radiator was the only condenser in the system then it would be bigger than a standard radiator.
Higher pressures in the cooling circuit do not lead to a reduction in the required radiator area. This is used simply to prevent the coolant from evaporating, which is not desireable in conventional cooling systems. Steam separators are used in conventional circuits to prevent vapour lock in the engine - which would cause issues with cooling and coolant flow. Both the Merlin and V-1710, for example, required steam separators for their cooling systems to work.
Higher pressure in the cooling system does allow for higher temperatures in the coolant without the danger of it becoming steam. The higher temperatures do allow for a reduction in radiator size, due to the higher temperature difference between the coolant and the air. However, the law of diminishing returns apply - as the coolant temperature rises more heat will be rejected to the lubrication circuit, and at a certain point any reduction in coolant radiator size is more than offset by the increase in oil radiator size. This is something that the USAAC discovered with the hyper engine program. Originally the coolant temperature was to be 300°F (149°C), but was reduced to 250°F (121°C) because it was discovered that the higher temperature gave no aerodynamic benefit.
Higher temperatures can also have an adverse affect on the combustion chamber - reducing the boost/compression ratio that can be used due to detonation.
wuzak
Captain
DonL
Banned
Evaporative cooling systems do not have to be total loss, as was teh case in the Me 209 V1.
Many of the Schneider Trophy racers used closed circuit evaporative cooling systems.
Take the MC.72, for example:
The copper coloured bits on the airframe (ie not painted red) are for cooling - most of them are condensers for the engine cooling system, though I believe the area around the nose is for oil cooling.
The condensers are there to convert steam back into liquid form. The liquid coolant having converted to steam after leaving the engine.
On the Fw 187-V5 it may be that the small radiator is a small condenser to compensate for a lack of surface area on the airframe, or simply a radiator used to further cool the re-liquified coolant.
If the radiator was the only condenser in the system then it would be bigger than a standard radiator.
Higher pressures in the cooling circuit do not lead to a reduction in the required radiator area. This is used simply to prevent the coolant from evaporating, which is not desireable in conventional cooling systems. Steam separators are used in conventional circuits to prevent vapour lock in the engine - which would cause issues with cooling and coolant flow. Both the Merlin and V-1710, for example, required steam separators for their cooling systems to work.
Higher pressure in the cooling system does allow for higher temperatures in the coolant without the danger of it becoming steam. The higher temperatures do allow for a reduction in radiator size, due to the higher temperature difference between the coolant and the air. However, the law of diminishing returns apply - as the coolant temperature rises more heat will be rejected to the lubrication circuit, and at a certain point any reduction in coolant radiator size is more than offset by the increase in oil radiator size. This is something that the USAAC discovered with the hyper engine program. Originally the coolant temperature was to be 300°F (149°C), but was reduced to 250°F (121°C) because it was discovered that the higher temperature gave no aerodynamic benefit.
Higher temperatures can also have an adverse affect on the combustion chamber - reducing the boost/compression ratio that can be used due to detonation.
What do you want to tell me?
The FW 187 V5 had only 20 Liter more water then the normal FW 187 A0. The whole system was totaly closed with only one overpressure valve.
It was not the same system as the He 100 system with a surface (wings) evaporation. The FW 187 had no surface evaporation!
Please show me anything to back up your claim!
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wuzak
Captain
I was pointing out that an evaporative cooling system could be a closed system. You made the statement that the Fw 187 V5 didn't have an evaporative cooling system because it was closed. That is my point/claim.
I have no knowledge of the specific system used on the V5. Other than a source that says it was evaporative cooling, without any details.
If the V5 cooling system was not an evaporative cooling system, and did not have surface coolers of any kind, then I would suggest that it had inadequate cooling for normal operation. Did any other Db 601 powered aircraft have radiators as small?
DonL
Banned
No and that's not my intention. From my technical understanding, the cooling system of the FW 187 V5 was an extreme high pressure water cooling sytem.
From this system the steam seperater was developed to the DB 605 production series. An evaporation system is in need for a surface evaportion!, but the FW 187 had no surface evaporation.
wuzak
Captain
Not correct.
The system used in the He 100 used surface condensers, not evaporators. The condenser is basically a type of radiator. And a condenser could, in fact, be a radiator.
The job of the condenser is to convert steam into water. The water having been changed into steam during the engine cooling process.
DonL
Banned
Ähm,
to my knowledge the He 100 had water cooling lines through the wings for evaporation and that is the focal point, because the FW 187 had no cooling lines through the wings or any other surface!
to my knowledge the He 100 had water cooling lines through the wings for evaporation and that is the focal point, because the FW 187 had no cooling lines through the wings or any other surface!
wuzak
Captain
Have you got this one also?
Focke-Wulf Fw 187 Der vergessene Hochleistungsjager: Dietmar Hermann and Peter Petrick: 9783925505669: Amazon.com: Books
I was just looking for the book you referenced (Focke-Wulf FW 187: An Illustrated History: Dietmar Harmann: 9780764318719: Amazon.com: Books) and found this other one - which appears to be only in German.
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DonL
Banned
I have the german version.
Focke-Wulf Fw 187 Der vergessene Hochleistungsjager: Dietmar Hermann and Peter Petrick: 9783925505669: Amazon.com: Books
Edit:
this is the english version:
http://www.amazon.com/dp/0764318713/?tag=dcglabs-20
Focke-Wulf Fw 187 Der vergessene Hochleistungsjager: Dietmar Hermann and Peter Petrick: 9783925505669: Amazon.com: Books
Edit:
this is the english version:
http://www.amazon.com/dp/0764318713/?tag=dcglabs-20
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wuzak
Captain
I google translated the title and came up with: "Focke-Wulf Fw 187 The forgotten high performance Jager".
This is the same book as "Focke-Wulf FW 187: An Illustrated History" ?
This is the same book as "Focke-Wulf FW 187: An Illustrated History" ?
DonL
Banned
You can translate it: "Focke-Wulf Fw 187 The forgotten high performance (figther)"
In german a fighter is a Jäger!
The original translation would be "a hunter", but in english it is a fighter.
Yes absolute the same!
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What production Fw 187 B? It never existed. This is my point. I don't disagree that the Fw 187 might have proven a good performer in service.
I do object to extrapolating specialist data from prototype aircraft and applying them to hypothetical production aircraft. These aircraft never flew and the data remain untested and unproven. You can choose to take them at face value if you wish, but I choose to be a little more sceptical. I would apply this scepticism to any unproven data about any aircraft, produced anywhere at any time. I am entitled to my opinion, just as you are to yours.
As for cooling, in my post showing the different intakes that's why I referred to V7's cooler intakes and the A-0's radiator intakes.
Cheers
Steve
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GregP
Major
DonL's replies got me interested in the Fw 187, at least enough to go look it up.
According to my references, admittedly not primary Focke-Wulf documents, they made nine Fw 187 aircraft. The first one used the Junkers Jumo 210Da engines of 621 HP and went 326 mph. The V2 – V5 airframes had Jumo engine with 671 HP and were 329 – 335 mph aircraft. The first 2 were single seaters and the rest were two seaters.
The 6th Fw 187, the V6 aircraft, was fitted with 1,060 HP DB 600A engines and surface evaporative cooling that was very problematic, but DID hit 395 mph in level flight. The aircraft suffered from skin buckling and reportedly had severe cooling problems. However, the Luftwaffe, the RLM, and Focke-Wulf all knew that any production aircraft would have had to use standard radiators and the top speed was calculated to be 348 mph with the DB 600A engines fitted with standard radiators.
There followed three Fw 187 A-0 airframes with Jumo 210G engines of 671 HP. These planes had a top speed of 329 mph at altitude and 322 mph at sea level.
So, I stand corrected when I said the P-38 was 80 mph faster than any Fw 187. It was actually 82 to 88 mph faster than 8 of the 9 Fw 187's and only 19 mph faster than the flawed but fast Fw 187 V6 with surface evaporative cooling that failed and was not proceeded with.
I found these data both on the web and in several books I have at home. All my references state the V6 had surface evaporative cooling and all mention the problems with it as well as skin buckling. So while it might be true that the V6 really did not have surface evaporative cooling, I can't prove that with any references I have at this time and they all state it DID have surface evaporative cooling.
In any case, the single Fw 187 V6 was not proceeded with, and this is the thing that makes me curious. Since the Fw 187 did show good performance, if not great. The performance of the V6 has to be taken with a grain of salt since it was calculated to be a 348 mph aircraft with real-world radiators, but it seems to me that the Fw 187 DID show enough to at least make it interesting.
In order to displace a weapon already in production, there has to be some improvement in performance, reliability, or SOMETHING, and the Fw 187 apparently didn't show improvement sufficient to warrant placing it into production in lieu of the Bf 110. The Bf 110 C-4 with DB 601B engines had a top speed of 348 mph … exactly the same as calculated for the Fw 187 when fitted with standard radiators. No improvement there in speed, and I have no reference for a maneuverability comparison with the Bf 110.
According to my references, admittedly not primary Focke-Wulf documents, they made nine Fw 187 aircraft. The first one used the Junkers Jumo 210Da engines of 621 HP and went 326 mph. The V2 – V5 airframes had Jumo engine with 671 HP and were 329 – 335 mph aircraft. The first 2 were single seaters and the rest were two seaters.
The 6th Fw 187, the V6 aircraft, was fitted with 1,060 HP DB 600A engines and surface evaporative cooling that was very problematic, but DID hit 395 mph in level flight. The aircraft suffered from skin buckling and reportedly had severe cooling problems. However, the Luftwaffe, the RLM, and Focke-Wulf all knew that any production aircraft would have had to use standard radiators and the top speed was calculated to be 348 mph with the DB 600A engines fitted with standard radiators.
There followed three Fw 187 A-0 airframes with Jumo 210G engines of 671 HP. These planes had a top speed of 329 mph at altitude and 322 mph at sea level.
So, I stand corrected when I said the P-38 was 80 mph faster than any Fw 187. It was actually 82 to 88 mph faster than 8 of the 9 Fw 187's and only 19 mph faster than the flawed but fast Fw 187 V6 with surface evaporative cooling that failed and was not proceeded with.
I found these data both on the web and in several books I have at home. All my references state the V6 had surface evaporative cooling and all mention the problems with it as well as skin buckling. So while it might be true that the V6 really did not have surface evaporative cooling, I can't prove that with any references I have at this time and they all state it DID have surface evaporative cooling.
In any case, the single Fw 187 V6 was not proceeded with, and this is the thing that makes me curious. Since the Fw 187 did show good performance, if not great. The performance of the V6 has to be taken with a grain of salt since it was calculated to be a 348 mph aircraft with real-world radiators, but it seems to me that the Fw 187 DID show enough to at least make it interesting.
In order to displace a weapon already in production, there has to be some improvement in performance, reliability, or SOMETHING, and the Fw 187 apparently didn't show improvement sufficient to warrant placing it into production in lieu of the Bf 110. The Bf 110 C-4 with DB 601B engines had a top speed of 348 mph … exactly the same as calculated for the Fw 187 when fitted with standard radiators. No improvement there in speed, and I have no reference for a maneuverability comparison with the Bf 110.
