Matronics Email Lists Forum Index Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
 
 Get Email Distribution Too!Get Email Distribution Too!    FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

914 High Altitude Performance

 
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> RotaxEngines-List
View previous topic :: View next topic  
Author Message
h&jeuropa



Joined: 07 Nov 2006
Posts: 634

PostPosted: Sat Jul 11, 2015 6:17 am    Post subject: 914 High Altitude Performance Reply with quote

We recently did a flight at a Density Altitude of 15000 ft. We were unable to maintain 30 in manifold pressure, the fuel flow was about 6.4 gph and the throttle position was 100%. We subsequently adjusted the wastegate cable less than 1 turn and replaced all the spring style clamps on our airbox pressure and manifold pressure instrumentation hoses with wraps of safety wire and now we easily get 30 in manifold pressure with fuel flow of 5.5 gph and throttle position around 70%.

When looking into this, we referred to the 914 performance charts found in chapter 5 of the Operators Manual and the critical flying altitude in chapter 2. Chapter 2 states that continuous performance manifold pressure is available up to 16000 feet when operated at ISA temperature and pressure. Yet the Performance graph for non-standard conditions, shows when the temperature difference from standard condition is 0 (so standard ISA conditions) the power drops from 74kw at SL to 66 kw at 16000 ft. This seems to conflict with the critical altitude statement.

And we have a copy of an early 914 Operators Manual (1996 05 10) where the same chart shows constant power at 0 deg difference up to 16000 ft. It also shows the same example as the current chart, Max continuous power at 10000ft, and the result is 74.9 kw versus the current chart that results in 72 kw.

Just looking for an explanation of the charts and definition of critical altitude.

Thanks

Jim & Heather
Europa XS


- The Matronics RotaxEngines-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RotaxEngines-List
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> RotaxEngines-List All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group