What kind of engine was fitted in the Nieuport 161 - 02?
At first, I need to go back about the Nieuport 161 to give a more comprehensive picture of this fighter.
It’s true, however, than the Morane-Saulnier MS 405-02, which flew a bit earlier in 1937, used a 920 Cv engine allowing her to reach 483 kph at 5,000 m (this engine was a prototype of the 12 Y 29).
It is the only credible French measure for the Morane 405 (given by G. Botquin in l'épopée du Morane 406, le Fanatique de l'Aviation, #100, p. 31, 1978) before the one obtained by the MS 405 #12, fitted with the 12 Y 45 engine and reaching 493 kph.
Indeed, the speed increment would be more than 20 kph, pushing the top speed over the 500 kph threshold.
The difference of 17 km/h with the Morane-Saulnier 405-02 / 406 would have been less important but always significant.
Regarding the Morane, the only credible climbing value was the one given by the CEAM who experimented the Bloch 152 fighter against the MS 405 #13 in December 1939 and reported the Morane, with her HS 12 Y 51 engine providing 1,000 hp, climbed to 4,000 m in 5’11” and to 8,000 m in 13’12”.
The very better Mörkö Morane, fitted with a Klimov M 105 P (1,050 hp at 4,000 m) needed 8’00” to climb to 5,000 m, giving a average ratio of 10.4 m/s.
The CEMA didn't spare Nieuport
From the other hand, fitting the up to date Hispano-Suiza 12 Y 29 on the Nieuport 161-02 was completely unlikely.
The Morane 406, being ordered, was tightly “protected” by the State services very influential deciders.
The managers of the Hispano-Suiza company never had another choice: The best engines must be provided to the chosen standard fighter.
The first plane to fly was the D.520-01 with a 12 Y 29 engine (920 Cv at 3,600 m ==> 527 kph at 5,000 m).
The second was the CAO 200-01 with a 12 Y 31 engine (860 hp at 3,150 m ==> 535 kph without exhaust pipes and 552 kph with that device).
The third was the Morane 450 with a 12 Y 51 engine (1,000 hp at 3,150 m -> 560 kph).
The fourth was the Arsenal VG 33-01 with a 12 Y 31 engine (860 hp at 3,150 m –> 558 kph with that device)
Clearly, the Morane company was favored and the SNCAO (ex Nieuport) was not favored at all.
With the same 1,000 hp engine, the very advanced CAO 200 could reach 595 kph, matching clearly with the Bf 109 F and the Spitfire V fighters.
In the site http://www.aviastar.org/air/france/nieuport-160.php, you can read a confirmation of that : The top speed of the Nieuport 160 was 440 kph, which is consistent with a top speed close to 500 kph with the 860 hp.
The second Nieuport 161 accident
It happened during trials for extra short landings, needed to satisfy the French Air administration.
For the landing, it was requested a maximum distance of 450 m after passing a 8 m virtual “tree”, with a wind speed slower than 2.5 m/s.
Obviously, such a trial was easy for all the old slow biplanes, but was much more difficult for very clean fighters, as that was perfectly illustrated by the Nieuport 161.
It may be added that the Nieuport fighter had a large span for its wings (11 m), with an aspect ratio of 8 (the MS 406 wings had 6.63). So the ground effect was very powerful.
This incident was especially used together with the first crash of September 1936 to vilified the Nieuport 161.
But another plane suffered from a similar crash during the same test: A Caudron Simoun, which was, also, a very clean aircraft.
The Morane, also, suffered 2 accidents!
The first accident occurred on the landing of the Lithuanian pilot Capt. Mikenas, written off the MS 405-01: For 2 sources, he died but, for a more recent source, he was only injured.
As usual, it was said that the pilot was responsible.
It was written "the fighter design was in no way the origin of this crash".
They described the graphical barometric record, displaying a regular climbing interrupted suddenly by a vertical dive until the ground level.
No pilot action was detected, so the crash was attributed to a fainting fit of the pilot occurring during the climbing.
It was claimed the supply oxygen device was thoroughly tested.
Nevertheless, such a crash may be easily related to the poor climbing ability of the Morane fighter, which was confirmed in the French handbook for the Curtiss P 36 A 1 (chapter I, end of the section entitled procédés de combat): There, you can read that, if the Curtiss climbed to 7,000 m in 11 minutes, the Morane 406 needed 18 minutes to reach the same altitude.
This fighter being able to reach 5,000 m in 10 minutes (each 1,000 m step in an average time of 2 minutes), she needed an average time of 4 minutes to climb each new step.
So, the 8,000 m needed at least 24 minutes and a supplementary 1,000 m altitude step exceeded easily 35 to 40 minutes.
That may be seen as a sufficiently long time for the freezing of some parts of the oxygen supply device.
I've read an interview of Michel Détroyat where he claimed the fighters will have no reason to fly at very high altitude, because that was very uncomfortable.
And a bad climbing ability was a good motive to reject this fighter (as all other bad climber ones).
This was expected from a plane designed by a company which had got several times the world record of altitude and was accustomed to elaborate efficient fighting planes.