Dewoitone 520 question (1 Viewer)

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Hello Tomo Pauk!

More sources for the 2 different D 520's are Profile Publication Number 135, The Dewoitine 520, page 13, and French Fighters of World War II in Action, Aircraft number 180, page 43.

By the way, the profile publication shows that D 520's during the Battle of France:

  1. Aircraft Destroyed Probable
  2. Bf-109E 23 10
  3. Bf-110 9 1
  4. Do 17/215 24 16
  5. He 111 16 8
  6. Hs 126 12 1
  7. Ju 87 14 3
  8. Ju 88 2 0
  9. Hs 123 1 0
  10. Cr 42 4 0
  11. Br 20 3 0


The cost was placed at 85 D 520's, only 54 due to direct enemy action, with 40 pilots killed, wounded or made prisoner, and 4 additional pilots killed or wounded in accidents.

The above data is somewhat different than Joe B's. I make no claim that this data is better or worse than his data. Please be aware however, that this data is from a 1966 publication, so if Joe's information is newer it may well be more accurate.

Hello Flyboy!

I do not have any information on how a D 520 would compare to a Spit Mk I or II. All I have is Eric Brown's impressions of the D 520 vs a Seafire IIC. As you might expect, he felt that the Seafire was superior in all aspects except rate of climb.


May God fly your wing!

Eagledad
 
Hello Flyboy!

I do not have any information on how a D 520 would compare to a Spit Mk I or II. All I have is Eric Brown's impressions of the D 520 vs a Seafire IIC. As you might expect, he felt that the Seafire was superior in all aspects except rate of climb.
Imagine that! Thanks for the info!
 
More sources for the 2 different D 520's are Profile Publication Number 135, The Dewoitine 520, page 13, and French Fighters of World War II in Action, Aircraft number 180, page 43.

By the way, the profile publication shows that D 520's during the Battle of France:

  1. Aircraft Destroyed Probable
  2. Bf-109E 23 10

The above data is somewhat different than Joe B's. I make no claim that this data is better or worse than his data. Please be aware however, that this data is from a 1966 publication, so if Joe's information is newer it may well be more accurate.
The book I quoted from ("The Battle of France-Then and Now") is much newer (it came out in the last few years) but I think the bigger difference is that this book researched the fates of individual a/c in both sides' records. Whereas, I would assume the number in the book you quoted is what the French pilots claimed at the time, especially due to the category 'probable'. If the D520 pilots claimed 23 Bf109's destroyed plus 10 probable, but actually destroyed 14, that would be a quite plausible rate of over claim, probably more accurate claiming than the whole WWII average of all air arms.

Joe
 
eagledad i think your info are for french claims, in "Battle of France-Then and Now" the losses are real losses crosschecked french and germans report
 
Hello Joe B and Vincenzo!

As I wrote, I have no quarrel with your figures. The 1966 data may well be just from French records available at that time, and would not include any examination of German data. Thank you for your responses!

Just one more bit of info, a Curtiss Hawk 75A did a 360 degree turn in 12 seconds, a D 520 in 15 seconds and a MS 406 in 18 seconds. Unfortunately, the altitude of the test is unknown.

May God fly your wing!

Eagledad
 
Just a gentle word of warning.

Captain Eric Melrose Brown, CBE, DSC, AFC, MA, Hon FRAeS, RN used to be quoted as a word form God. Now some seem to assume everything he wrote was biased. He was as human as any of us and his opinions were based upon his experiences to date and, of course, coloured by them as ours would be. Do you know an American who thinks the P51 is rubbish, a Briton who thinks the Spitfire was a waste of time or a German who thinks an Me109 was an overengined lightweight?.

Nevertheless he was hugely experienced and respected as a man, as a pilot generally and as a test pilot in particular, by his peers who knew better than us. His notes should be taken as a genuine reflection of the aeroplanes he flew, as he found them, on the day. Equally we should be careful not to therefore assume that individual aeroplane X he flew was identical to all types of aeroplane X. Only that the individual aeroplane X he flew actually performed as he found on that day.
 
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Just a gentle word of warning.

Captain Eric Melrose Brown, CBE, DSC, AFC, MA, Hon FRAeS, RN used to be quoted as a word form God. Now some seem to assume everything he wrote was biased. He was as human as any of us and his opinions were based upon his experiences to date and, of course, coloured by them as ours would be. Do you know an American who thinks the P51 is rubbish, a Briton who thinks the Spitfire was a waste of time or a German who thinks an Me109 was an overengined lightweight?.

Nevertheless he was hugely experienced and respected as a man, as a pilot generally and as a test pilot in particular, by his peers who knew better than us. His notes should be taken as a genuine reflection of the aeroplanes he flew as he found them on the day. Equally we should be careful not to therefore assume that individual aeroplane X he flew was identical to all types of aeroplane X. Only that the individual aeroplane X he flew actually performed as he found on that day.

And right there answers the feeling about Brown. he indeed was a very talented test pilot and engineer, but much of his gospel was based on inital flights.
 
Hello Tomo Pauk!

D 520 no 3 was a standard early production aircraft that would have been found during the Battle of France. D 520 No 465 had a HS 12Y49 motor compared to no3's HS 12Y45, a revised front cowling (more streamlined), and "jet" exhaust stacks. My understanding is that No 465 is more representative of late production D520s, and would have appeared late in 1941.

May God fly your wing!

Eagledad

I've took a look at what the No.465 had improved over BoF Do.520s, from the 'French fighters in action'). It includes addition of boundary layer 'trap' (separator?) for the coolant radiator, individual exhaust stacks, replacement of the oil cooler by a heat exchanger (but it does not explain how was that accomplished). The changes were made in late 1941, so it remains unclear whether such improvements would've been made in late 1940, for service in 1941 (providing France is undefeated by then). Such improvements, along with installment of the latest 1100 HP 12Y engines (let alone the 12Z engines), would've made the D.520 a potent warbird for 1941. Alas, it wasn't meant to be.
 
Hello


The number N° 13 had better speed (549 km/hin fact) at 700 m higher than the N°2, because of better designed duct inlets, leading to dynamic pressure improvement.

I'd rather quote the D-520 airframe: exept some teething troubles (with engine oil cooling), it was competitive in overall performance against Me-109 despite its weaker hispano engine (885-910 hp vs 1050 at height).

I have some doubts about quick developpement of Hispano Suiza engines.Y-31 and 45 were running on 85 octanes fuel, the 1000 hp Y-51 used 100 octanes fuel, thant mean massive imports from USA and GB.
Soviet M-105 engines were running on 91-92 octanes one. Maybe M-103? But once again it's 950-960 hp at best, no much progress...
Probably the best immediate solution was a french kind of Yak-1/Yak-3, Hellcat/Beracat transition from the D-520 to the D-551.
Dewoitine D-551 - Chasseur - Un sicle d'aviation franaise, les avions franais

Regards
 
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Poor ground handling is usually ther esult of the landing gear being too far forward or not aligned correctly. Either one is easy to fix. Moving the gear is not easy on an existing airframe, but is relatively simple when you build a new one.

The D.520's performance was not tip top, but it was in the category of the Me 109E.

In my opinion, all the faults could have been corrected and it could have been a good fighter. The development may or may not have had wonderful potential, but the D-520 could have been fixed into a pretty decent fighter. I don;t know if it had CG issues, good or poor roll, or much aboutit, I once flew an RC model of it and it flew as well as anything else RC I ever flew. That's no proof of anything, but the outline was pretty scale and it could have been made to fly well.
 
The D-551 offered speed but in other ways it might be seen as retrograde. Smaller wing means higher wing loading, higher landing speed and larger turning circle. Retractable landing SKID means better streamlining and performance, what is does for ground handling??? View from cockpit is also a bit suspect.

d550-3.jpg


For another view

Flashback on glorious planes


I am not as confidant that just sticking 100 octane fuel in the tank would have lead to big increases in power. Did the Hispano have the strength to stand up to the higher pressures in the cylinders without failing? Didn't the Russians narrow the bores a couple of mm and add weight? Poorer materials or engine wasn't strong enough?
 
Just a gentle word of warning.

Captain Eric Melrose Brown, CBE, DSC, AFC, MA, Hon FRAeS, RN used to be quoted as a word form God. Now some seem to assume everything he wrote was biased. He was as human as any of us and his opinions were based upon his experiences to date and, of course, coloured by them as ours would be. Do you know an American who thinks the P51 is rubbish, a Briton who thinks the Spitfire was a waste of time or a German who thinks an Me109 was an overengined lightweight?.

Nevertheless he was hugely experienced and respected as a man, as a pilot generally and as a test pilot in particular, by his peers who knew better than us. His notes should be taken as a genuine reflection of the aeroplanes he flew, as he found them, on the day. Equally we should be careful not to therefore assume that individual aeroplane X he flew was identical to all types of aeroplane X. Only that the individual aeroplane X he flew actually performed as he found on that day.

I understand what you are saying and as a general rule I would agree with you, but I have to wonder what Mr. Brown was smoking when he rated the Fairey Swordfish as a better torpedo bomber then the Grumman Avenger. Englishman or not, I doubt there is another person on the planet that would arrive at that conclusion.
 
The link above suggests the tendency to turn when on the ground was due to lack of a tailwheel locking device ... and ity was corrected in later models.

The link also suggest the D.20 had good roll and general manruverability, suggesting it would have been a pretty decent pick for a front line fighter of the day.

I find it hard to believe that the D.520 was a complete dog, and think that, although I really like Eric Brown, perhaps he was writing about a fighter with horrible ground handling that would have been and WAS easily correctable, but pretty decent flight manners.
 
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I understand what you are saying and as a general rule I would agree with you, but I have to wonder what Mr. Brown was smoking when he rated the Fairey Swordfish as a better torpedo bomber then the Grumman Avenger. Englishman or not, I doubt there is another person on the planet that would arrive at that conclusion.

I believe in terms of tonage sunk the Fairy Swordfish was the most succesfull torpedo bomber of the war, so there is an objective basis for this. The aircrafts abillity to fly slow and to fly low and attack at night seemed to be its winning card. I've looked long and hard at why the Swordfish got through to the Bismark. The Bismarks heavy AAA was at the time the best in the world on a par with the USN Ford range keeper, a fully triaxially stabalised tachymetric synthetic system with remote power control while the medium 3.7cm AAA was also gyro-sta. The bismarks FLAK was based around triaxially stabilised directors and could throw up 60-80rpm while some of the Quad 2.0cm FLAK units were also stabalised. The reality seems to have been the aircrafts low flying abillity and the aircrafts abillity to exploit the bad weather eg hiding behined waves and clouds. Surviving German sailers complained of seeing the aircraft only intermittantly as they approched.

My conclusion is that no navy in the world had the abillity to deal with the Swordfish in those circumsatances at that time nor did many aircraft have abillity to exploit those weaknesses in most ships defenses. A few years latter and everyone has vastly improved their AAA.

Of course the Krisgsmarine never had a chance to finnish its aircraft carriers Graf Zeppelin or Seydlitz so Swordfish were seldim confronted with intercepting fighters.
 
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However much potential the D520 had, it first flew in October 1938. At least 2 years behind where it should be and inferior to the Spitfire and 109 and marginally better than a hurricane. Not good.

The Fw190 flew only 8 months later. The 520 was old news and marginal news at best. It may have been the best French fighter but 2 years too late.
 
I believe in terms of tonage sunk the Fairy Swordfish was the most succesfull torpedo bomber of the war, so there is an objective basis for this. The aircrafts abillity to fly low and to fly low and attack at night seemed to be its winning card. I've looked long and hard at why the Swordfish got through to the Bismark. The Bismarks heavy AAA was at the time the best in the world on a par with the USN Ford range keeper, a fully triaxially stabalised tachymetric synthetic system with remote power control while the medium 3.7cm AAA was also gyro-sta. The bismarks FLAK was based around triaxially stabilised directors and could throw up 60-80rpm while some of the Quad 2.0cm FLAK units were also stabalised. The reality seems to have been the aircrafts low flying abillity and the aircrafts abillity to exploit the bad weather eg hiding behined waves and clouds. Surviving German sailers complained of seeing the aircraft only intermittantly as they approched.

My conclusion is that no navy in the world had the abillity to deal with the Swordfish in those circumsatances at that time nor did many aircraft have abillity to exploit those weaknesses in most ships defenses. A few years latter and everyone has vastly improved their AAA.

Of course the Krisgsmarine never had a chance to finnish its aircraft carriers Graf Zeppelin or Seydlitz so Swordfish were seldim confronted with intercepting fighters.

You are making a torpedo runon a ship somewhere in the Pacific Theater, a Zero is moving in to intercept you and you have no fighter escort, or if you do they are busy, would you choose a Swordfish? or an Avenger? The correct answer for everyone on the planet besides Eric Brown is Avenger.
 
I believe in terms of tonage sunk the Fairy Swordfish was the most succesfull torpedo bomber of the war, so there is an objective basis for this. The aircrafts abillity to fly low and to fly low and attack at night seemed to be its winning card. I've looked long and hard at why the Swordfish got through to the Bismark. The Bismarks heavy AAA was at the time the best in the world on a par with the USN Ford range keeper, a fully triaxially stabalised tachymetric synthetic system with remote power control while the medium 3.7cm AAA was also gyro-sta. The bismarks FLAK was based around triaxially stabilised directors and could throw up 60-80rpm while some of the Quad 2.0cm FLAK units were also stabalised. The reality seems to have been the aircrafts low flying abillity and the aircrafts abillity to exploit the bad weather eg hiding behined waves and clouds. Surviving German sailers complained of seeing the aircraft only intermittantly as they approched.

My conclusion is that no navy in the world had the abillity to deal with the Swordfish in those circumsatances at that time nor did many aircraft have abillity to exploit those weaknesses in most ships defenses. A few years latter and everyone has vastly improved their AAA.

Of course the Krisgsmarine never had a chance to finnish its aircraft carriers Graf Zeppelin or Seydlitz so Swordfish were seldim confronted with intercepting fighters.

There is a lot to what you say. Its a personal view but HAA without proximity fuses always struck me as not very effective. The 37mm on the Bismark were very poor, they were almost single shot with each shell manually loaded. The mounting may well have been top draw but the guns were dreadful. This only left the 20mm which were I believe 12 - 18 single mounts which isn't much for a ship of her size.
 
You are making a torpedo runon a ship somewhere in the Pacific Theater, a Zero is moving in to intercept you and you have no fighter escort, or if you do they are busy, would you choose a Swordfish? or an Avenger? The correct answer for everyone on the planet besides Eric Brown is Avenger.

Ah, but after you drop the torpedo you are in the only torpedo bomber that can out turn a Zero. :lol:
 
You are making a torpedo runon a ship somewhere in the Pacific Theater, a Zero is moving in to intercept you and you have no fighter escort, or if you do they are busy, would you choose a Swordfish? or an Avenger? The correct answer for everyone on the planet besides Eric Brown is Avenger.

While I might choose Avenger in that situation, would that make much difference. in 42 at Midway Avengers of VT ? operating from Midway suffered 83% losses and the only survivor limbed back badly damaged, ok all six Swordfishes which tried to attack KM heavy units during the Channel Dash were shot down but Fw 190A had more firepower than Zero. The fact was that both Avenger and Swordfish needed fighter escort to survive determined fighter opposition. On the other hand if the target ship had good AA and there was overcast, then Swordfish could use the clouds for sneak approach then made a deep dive to sea level near the dropping point and then drop its fairly reliable torpedo, Avenger on the other hand during the early part of the Pacific War had only one one option, steady rather slow and low approach because the unreliable Mark 21 torpedo had at that time very tight dropping paramets, so Avenger offered much easier firing solution to AA gunners and still it was more probable that Mark 21 malfunctioned than the British 18". In 44 situation was changed because mods allowed dropping of Mark 21 clearly higher and at clearly higher speed.

Juha
 
While I might choose Avenger in that situation, would that make much difference. in 42 at Midway Avengers of VT ? operating from Midway suffered 83% losses and the only survivor limbed back badly damaged, ok all six Swordfishes which tried to attack KM heavy units during the Channel Dash were shot down but Fw 190A had more firepower than Zero. The fact was that both Avenger and Swordfish needed fighter escort to survive determined fighter opposition. On the other hand if the target ship had good AA and there was overcast, then Swordfish could use the clouds for sneak approach then made a deep dive to sea level near the dropping point and then drop its fairly reliable torpedo, Avenger on the other hand during the early part of the Pacific War had only one one option, steady rather slow and low approach because the unreliable Mark 21 torpedo had at that time very tight dropping paramets, so Avenger offered much easier firing solution to AA gunners and still it was more probable that Mark 21 malfunctioned than the British 18". In 44 situation was changed because mods allowed dropping of Mark 21 clearly higher and at clearly higher speed.

Juha

We should ignore how reliable the torpedo is, we are strictly talking about an airframe here. If you were sent out to attack the battleship Yamato near the end of the war, Would you have chosen the Swordfish or the Avenger?

Eric Brown picked the Swordfish over the Avenger as an overall better aircraft, and that is rediculous. Possibly, under cover of night, with pea soup fog, driving rain, and a hurricane for cover, the Swordfish on one mission out of a thousand might be the better platform than the Avenger. But for the other 99.999% of missions there is no question which would be the better platform to deliver a torpedo, a bomb, or a mine. The fact that Eric Brown picked the Swordfish as an overall better platform for weapons delivery makes me call his overall judgement into question.
 

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