What was the Heinkel He 177's True Speed?

[SpicyJuan11]

I came across this thread and I saw two contradictory primary sources for the He 177's max speed. I saw 340 mph (550 kph) and 298 mph (480 kph). Does anyone know what the true top speed for this aircraft was, particularly for the A-5 variant? What was the cruise and max speed for a fully loaded A-5?

I have checked my own secondary references as well and am finding the same contradiction. Any help would be greatly appreciated.

 

[pbehn]

Isnt the difference between versions with and without flame dampers?

 

[Capt. Vick]

Whatever it is, I wouldn't believe it. The He 177 was a notorious liar.

 

[SpicyJuan11]

Isnt the difference between versions with and without flame dampers?

Yes I believe so, but would they account for a 40 mph difference? Besides, I am finding discrepancies within and between Griehl's He 177 book along with other sources.

 

[SpicyJuan11]

Whatever it is, I wouldn't believe it. The He 177 was a notorious liar.

Sorry, I don't get the joke

 

[tomo pauk]

The 550 km/h seems to be manufacturer's figure, ie. best case possible?

 

[SpicyJuan11]

The 550 km/h seems to be manufacturer's figure, ie. best case possible?

Considering that by 1944 the A-3 and DB 610 had been in "widespread" service for awhile, why would a fantasy figure be used instead of an actual one? I'm not at all saying you're wrong, just trying to understand.

In his appendix, Griehl lists the max speed of the A-1 through A-3/R5 of 298 mph (and cruise speed of 255mph), the A-5/R2 max speed of 273mph (236mph) [I guess this is flame dampeners?], A-5/R7 and A-6/R1 max speed of 323 mph (273 mph), A-7 (DB 610) 336 mph (273 mph).

 

[tomo pauk]

Considering that by 1944 the A-3 and DB 610 had been in "widespread" service for awhile, why would a fantasy figure be used instead of an actual one?

Used by whom?
For example, we can take a look at I-16 speed figure at English-language Wikipedia, it shows the best I-16 as being faster than Hurricane I, that is not supported by any Russian-language source - not even by the one quoted by them: Shavrov's bible. What Shavrov says on pg. 470 of his 1st tome is that speed achieved by the I-16 Type 24 was 489 km/h at altitude (440 km/h at S/L), against the calculated speed figure of 525 km/h for that version.

 

[pbehn]

Yes I believe so, but would they account for a 40 mph difference? Besides, I am finding discrepancies within and between Griehl's He 177 book along with other sources.

Impossible for me to say, its certainly possible that a best to worst case was 40MPH. Things like fitting a rear mirror to a Spitfire or painting a Mosquito matt black had a much bigger effect than a layman would think possible. In my opinion top speed on such aircraft is purely academic, cruising speeds were most important.

 

[Koopernic]

The number could have arisen from two sources. Firstly the Heinkel projected speed estimate when the project was started of 342mph and secondly a stripped down long range reconnaissance version. I can't remember which one.

 

[tt33]

This is from the magazine Flugzeug Classic Special issue 4 from 2009:

This is from the magazine Flugzeug Classic issue 6 from 2023:

Aero Series 13 Heinkel 177 Greif:

Bombers of the Luftwaffe: