What is reason for service ceiling? NAMC YS-11 and others

[wf971]

Hi there
I am wondering about a technical definition. It regards the NAMC YS-11, which according to most sources seems to have a service ceiling around 22.000 feet. As the very comparable FH227, with a few thousand pounds less and nearly the same engines, can achieve a cervice ceiling of 28.000, I suppose the ceiling can be related to climb performance? That has certainly been a concern for people who bought the YS-11, and find it overperforms (rather extremely!) In sim we can easily get to FL330 on the hottest day at MTOW, but irl it was reportedly very, very sedate and didn't climb half as fast as IniBuild's aircraft does. But could it instead, feasibly, be determined by a pressurization system that isn't quite as capable as Fokker/Fairchild-Hill's system? (Leaving now aside the ridiculous climb performance of the YS-11 (youtube)).

The YS-11's servicing manual (pp.931-41) seems to, at the end of its chapter on pressure, suggest a cabin altitude around 10.000ft plus/minus 300ft will produce an alarm in the cockpit. In the game Inibuilds did not provide a pressure regulator (png) -- but we can plainly see the max pressure differential (png). The manual describes a system that only manages 8900ft cabin altitude by the time it gets to 4-4.5 psi. Which altogether suggests to me this system is either designed economically to fit beneath the stated service ceiling, or it is simply the component whose weaknesses bottlenecked the YS-11.

 

I could be outrageously wrong here. Maybe those pressurization systems have nothing to do with the ceiling. Certainly it fits the underperformer-image of the YS-11 to suggest the service ceiling is determined by the powerplants. 

(I'll probably find more answers by asking on random age-old Piedmont Airlines youtube videos ;D ex-pilots and ex-handlers always seem to appear in those comment sections. Although they won't know about the inibuilds plane)

Edited 16 hours ago by wf971
clarified url was for youtube video