Bristol Blenheim

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Re: Bristol Blenheim

Post by Juha Tompuri » 25 Aug 2010 21:03

Vaeltaja wrote:
I seem to trust on the Finnish flight tests (Do you?)
After seeing Finnish flight test result of SB-2s.. Nope, not really.
What is there that that bothers you, and makes you not to trust on the Finnish Blenheim tests?

Regard, Juha

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Re: Bristol Blenheim

Post by Mangrove » 25 Aug 2010 21:08

Juha Tompuri wrote: The Finnish Blenheim bombload thing is a bit unclear to me, but AFAIK during Winter War the max (theorethical) bombload of the planes with Finnish bombracks was something 900-1000 kg
The ones with English bombracks, 563- or 527 kg
Series I (Mk.I, British) = 1000 lb. or 900 kg (8x100 + 4x25 kg.) with Finnish racks.
Series II (Mk.I, Finnish) = 922 kg. (8x100 + 4x12,5 + 24x3 kg.)
Series III (Mk.IV, British) = 1160 lb. (4x250 + 4x20 + 4x20 lb.)

Series IV (Mk.I, British) = ""
Series V (Mk.I, Finnish) = 972 kg. (8x100 + 4x25 + 24x3 kg.)
Series VI (Mk.IV, Yugoslavian/Finnish) = ""

Here's one with 8 x 100 kg load.
http://digi.narc.fi/digi/fullpic.ka?kuid=2917762

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Slon-76
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Re: Bristol Blenheim

Post by Slon-76 » 25 Aug 2010 21:21

Vaeltaja wrote: Well.. If we agree that Blenheim and SB-2 had roughly comparable performance and that I-16 (not actually sure which I-16s were used in Winter War) had higher top speed than what Fokker D XXI had (at least according to Finnish pilots it was so). Then Soviet I-16s should have had better chance of taking chasing and taking down Finnish Blenheims than what Finnish Fokker had chance of chasing down and dropping SB-2s.
About I-16.
In winter war participated I-16 type 5, 10, 17, 18, 19 and 27. The basic was I-16 type 5. For example, in structure of 59 air brigades and 68 IAP on 30.01.49 was 81 ê-16 type 5, 19 type 10, 19 type 17, 14 type 18, 3 type 19 and 7 type 27/ On the ski chassis (which it was not removed, as against other types) type 5 flied more slowly, than D.XXI(under the statement of the pilots flying on old type 5 of release of 36-37 years, the plane was not dispersed more than 320 km/h).
I caught two retreating enemy fighters rather easily because they were the type with fixed undercarriages. I.Juutilainen

About Blenheim.
You argue as if the question is not war, and about races. SB flied groups. In structure of a squadron on the maximal speeds, as is known, do not fly. Speed building is equal to as far as the slowest plane can quickly fly. For example, at to purpose SB with a speed of 280-320 km/h usually flied, back tried faster certainly. But if, for example, in group the damaged plane was, it reduced speed of all. In the theory, D.XXI had very bad chances to catch up SB, but in practice caught up and not with time.
Blenheims flied, as a rule, alone. And to their crews nobody prevented to use high-speed characteristics of the machines on a maximum. At I-16 type 5 with the fixed ski chassis of chances to catch up Blenheim there was a minimum, only at very successful coincidence of circumstances. Superiority I-16 type 18 in speed too conditional enough. The Blenheim's pilot could leave a flat dive that group SB to itself did not presume. Therefore, as I already spoke, to compare Blenheim and SB is senseless, because it is completely different tactics of application.
To measures of 1939 Blenheim was quite to itself the modern high-speed machine, capable to operate in the afternoon alone. Having bought these planes, the Finnish Air Forces for the first time in the history have not tailed after progress, and went in a leg with it.

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Re: Bristol Blenheim

Post by Juha Tompuri » 25 Aug 2010 21:32

Martti Kujansuu wrote: Series I (Mk.I, British) = 1000 lb. or 900 kg (8x100 + 4x25 kg.) with Finnish racks.
Series II (Mk.I, Finnish) = 922 kg. (8x100 + 4x12,5 + 24x3 kg.)
Series III (Mk.IV, British) = 1160 lb. (4x250 + 4x20 + 4x20 lb.)

Series IV (Mk.I, British) = ""
Series V (Mk.I, Finnish) = 972 kg. (8x100 + 4x25 + 24x3 kg.)
Series VI (Mk.IV, Yugoslavian/Finnish) = ""
The unclear thing for me is the wording at the Raunio book.
Here about the Series I:
"...neljä 12.5-25 kiloista siipeen"
In english: "four 12.5-25kg bombs to a wing"
What bothers me is that to :
"a wing" = four bombs of 25kg to both wings = 2x4 bombs in total
or to:
"wings"= four bombs of 25kg - two bombs to each wing.

And about the same with the series III wing racks.
Where there two or four 20 lbs bombs at each wing?
Martti Kujansuu wrote:A 250 kg bomb is not the same as five 50 kg bombs, since it is my understanding the destructive power of the bomb grews by the volume, that is power of three. A 100 kg bomb might not have destroyed those half a dozen tanks that were destroyed by Blenheims on July 4th 1941 at Karelian Isthmus. Fokkers usually had the same targets as Blenheims; convoys, factories, railway stations and such. To really access their success we need Soviet loss data.
AFAIK no Finnish plane was able to carry 250kg bombs during Winter War.

Regards, Juha

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Re: Bristol Blenheim

Post by Juha Tompuri » 25 Aug 2010 21:41

Finnish aerial bombs:
http://digi.lib.helsinki.fi/pienpainate ... &id=347159

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Re: Bristol Blenheim

Post by Vaeltaja » 25 Aug 2010 22:01

To Juha Tompuri...

First the listed result of the Blenheim maximum speed was on other sites always claimed on Blenheim I. Elsewhere Blenheim IVs all gained speed results around 420 to 430 kph. Finnish data seems to exist as an outlier as Finns gained higher top speed with Blenheim IVs and lower with Blenheim I. Then we have the second example, the SB-2. Again Finnish data seems to exists as an outlier. Of course there could be plausible explanations - perhaps something like Mercury XVs in type I hull and/or not being able to tune/repair properly the war booty engines - for both but it doesn't seem too good at first glance.

To Slon-76:

Ok.. I sorta wondered that same thing as in several occasion I-16s seem to be faster than Fokkers and a bit later they were able to catch withdrawing I-16s. Though i always assumed it was due the diving qualities of the Fokker but the wide variety of I-16s would explain that as well.

And yes. What i aimed to debunk was the claim - or something i perceived as a such a claim - that Blenheim would have been somehow exceptional aircraft at the time of the Winter War. From the data (apart from Finnish test data) the Blenheim does not appear to be exceptional aircraft in any sense for a light bomber of its era - not exceptionally fast, long ranged or having strong defensive armament. Which points out that something else than the aircraft itself was required to be considerably different in Finnish operations compared with Soviet operations for the Blenheim to have been operating as successfully as it did. That is to say quality (tactics) and daring of the bomber crews seems to have been far more important than perceived 'superior' qualities of the aircraft for the Blenheim's successes in the Winter War.

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Re: Bristol Blenheim

Post by Juha Tompuri » 25 Aug 2010 22:33

Vaeltaja wrote:To Juha Tompuri...

First the listed result of the Blenheim maximum speed was on other sites always claimed on Blenheim I. Elsewhere Blenheim IVs all gained speed results around 420 to 430 kph. Finnish data seems to exist as an outlier as Finns gained higher top speed with Blenheim IVs and lower with Blenheim I.
The Finnish MK IV data is with the local 100 octane fuel and with some extra boost.
Vaeltaja wrote:Then we have the second example, the SB-2. Again Finnish data seems to exists as an outlier. Of course there could be plausible explanations - perhaps something like Mercury XVs in type I hull and/or not being able to tune/repair properly the war booty engines - for both but it doesn't seem too good at first glance.
The tests were flown with ordinary planes, not with factory polished ones,

Vaeltaja wrote:And yes. What i aimed to debunk was the claim - or something i perceived as a such a claim - that Blenheim would have been somehow exceptional aircraft at the time of the Winter War. From the data (apart from Finnish test data) the Blenheim does not appear to be exceptional aircraft in any sense for a light bomber of its era - not exceptionally fast, long ranged or having strong defensive armament. Which points out that something else than the aircraft itself was required to be considerably different in Finnish operations compared with Soviet operations for the Blenheim to have been operating as successfully as it did. That is to say quality (tactics) and daring of the bomber crews seems to have been far more important than perceived 'superior' qualities of the aircraft for the Blenheim's successes in the Winter War.
Seems to have been faster than the majority of the enemy planes.
Vaeltaja wrote: Blenheim does not appear to be exceptional aircraft in any sense for a light bomber of its era
Pretty fast it was.


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Re: Bristol Blenheim

Post by Vaeltaja » 26 Aug 2010 05:58

Pretty fast it was.
Pretty fast, yes just like the other light bombers. Exceptionally fast, no. Having outstanding performance, no.

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Re: Bristol Blenheim

Post by Juha Tompuri » 26 Aug 2010 06:32

Vaeltaja wrote:
Pretty fast it was.
Pretty fast, yes just like the other light bombers.
Others?
When bought, and also after that Blenheim seems to have compared well against the "others".
Vaeltaja wrote:Exceptionally fast, no. Having outstanding performance, no.
As above.
Also exceptional and outstanding in that sense that at no time after Winter War Finnish bombers had such freedom of operations because of their performance.

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Re: Bristol Blenheim

Post by Vaeltaja » 26 Aug 2010 06:44

Juha Tompuri wrote:Others?
When bought, and also after that Blenheim seems to have compared well against the "others".

When bought, yes it was exceptionally fast aircraft with outstanding performance - for mid 1930s light bomber. Already by 1939 it was no longer exceptionally fast (Do 17s, SB-2s had already caught up with it - as had fighter designs) nor was it's performance any longer as outstanding as it had been.
Juha Tompuri wrote:As above.
Also exceptional and outstanding in that sense that at no time after Winter War Finnish bombers had such freedom of operations because of their performance.
As an aircraft it was not exceptional nor was it outstanding by the Winter War. More like average for a light bomber design. How (and how well) it was used is another story. Captured Pe-2s and Pe-3 might have been able to repeat that had they been used for that purpose.

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Re: Bristol Blenheim

Post by John Hilly » 26 Aug 2010 11:38

Come on Guys! Honestly!
Is there any sense left in this argument. Everyone has made his point several times. Neither this "picking of pins and needles" by the Finnish partitipians, nor the only cool opinions in here from Russia by Sloan, can bring us very much further!

Isn't it a time to return to the original Topic, the blunders?
There is lots of matters that can give an opportunity to a fair discussion.
Save energy, change subject! :lol:

Still, with best
Juha-Pekka :milwink:
"Die Blechtrommel trommelt noch!"

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Re: Bristol Blenheim

Post by Juha Tompuri » 26 Aug 2010 17:30

John Hilly wrote:Come on Guys! Honestly!
Is there any sense left in this argument.
Actually no arguing at my case, just trying to steer this discussion honest and fact-based.

Regards, Juha

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Re: Bristol Blenheim

Post by Juha Tompuri » 26 Aug 2010 17:47

Vaeltaja wrote:
Juha Tompuri wrote:Others?
When bought, and also after that Blenheim seems to have compared well against the "others".

When bought, yes it was exceptionally fast aircraft with outstanding performance - for mid 1930s light bomber. Already by 1939 it was no longer exceptionally fast (Do 17s, SB-2s had already caught up with it - as had fighter designs) nor was it's performance any longer as outstanding as it had been.
Not that outstanding as it has been, yes.
However able to outperform most of the enemy planes. Not bad for mid 30's plane.
Vaeltaja wrote:
Juha Tompuri wrote:As above.
Also exceptional and outstanding in that sense that at no time after Winter War Finnish bombers had such freedom of operations because of their performance.
As an aircraft it was not exceptional nor was it outstanding by the Winter War. More like average for a light bomber design.
Faster than average.
Vaeltaja wrote:Captured Pe-2s and Pe-3 might have been able to repeat that had they been used for that purpose.
Well... Pe-3 wasn't a bomber and when the Pe-2's entered Finnish service, there were enemy service fighters that were +100km/h faster than it.

Regards, Juha

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Re: Bristol Blenheim

Post by Slon-76 » 26 Aug 2010 18:38

Juha Tompuri wrote:
Vaeltaja wrote:
Vaeltaja wrote:Captured Pe-2s and Pe-3 might have been able to repeat that had they been used for that purpose.
Well... Pe-3 wasn't a bomber and when the Pe-2's entered Finnish service, there were enemy service fighters that were +100km/h faster than it.
Ideal would be SR-71 :D

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Re: Bristol Blenheim

Post by Vaeltaja » 26 Aug 2010 20:06

Juha Tompuri wrote:Not bad for mid 30's plane.
That is certainly true.
Juha Tompuri wrote:Faster than average.
Both Do 17Z and SB-2M-103 had perfectly comparable performance. Hence.. average. Please do note that there were several even faster light bomber designs around as well - they have just got less publicity.
Juha Tompuri wrote:Well... Pe-3 wasn't a bomber and when the Pe-2's entered Finnish service, there were enemy service fighters that were +100km/h faster than it.
Those were the fastest remotely bomber resembling aircraft Finns had. And AFAIK Pe-3 was able to carry some bombs.

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