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  #11  
Old 12-03-2019, 04:09 PM
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emsvitil emsvitil is offline
 
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  #12  
Old 12-03-2019, 05:17 PM
BobTurner BobTurner is offline
 
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Quote:
Originally Posted by partner14 View Post
. Flying with half throttle, 2,230rpm, climbing at 200fpm, at 15,480',
I have to ask: Why would one fly at half throttle, at 15K??
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  #13  
Old 12-03-2019, 05:23 PM
Latech15 Latech15 is offline
 
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I was happy with my 200kts ground speed in my 6 this week. I was down at 7k and I had to make the return trip in the afternoon. As awesome as 200kts was going, 120 on the way back SUCKED.
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  #14  
Old 12-03-2019, 07:33 PM
partner14 partner14 is offline
 
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As far as flying at half throttle.... My engine (IO540) has higher compression and cold air induction, so I pay really close attention to CHT's. Sometimes the temps are fine at WOT, but a higher percentage of the time they're not. You can see the numbers, they're almost perfect.... they wouldn't be if I was WOT. Can't totally tell you why, but after 1,100 hours I have a pretty good handle on what my engine wants and needs. Also I fly by mpg. So even at lower altitudes, if I run several inches less, ususally the mileage is greater. Most pilots don't even mess with the settings, I do. If I gave it those extra 2 inches, sure let's say I pick up from 160kts to 165kts (3% increase), but my fuel burn went from 9.5 to 10.2gph (7.4% increase).
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  #15  
Old 12-04-2019, 02:44 AM
Capt Capt is offline
 
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Guys please have a read of the article " Flying high and fast" by Ken Krueger, (Google it) makes for some sobering thoughts as a lot of pilots don't understand that VNE at Altitude is NOT based on IAS but TAS.
The Vans designs are very capable of exceeding VNE under certain conditions with fluttering.
Stay safe out there, learn something new everyday -)
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  #16  
Old 12-04-2019, 07:56 AM
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Snowflake Snowflake is offline
 
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Quote:
Originally Posted by Latech15 View Post
I was happy with my 200kts ground speed in my 6 this week. I was down at 7k and I had to make the return trip in the afternoon. As awesome as 200kts was going, 120 on the way back SUCKED.
Just think how badly it would suck in a Cessna...
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  #17  
Old 12-04-2019, 08:21 AM
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Toobuilder Toobuilder is offline
 
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Quote:
Originally Posted by partner14 View Post
As far as flying at half throttle.... My engine (IO540) has higher compression and cold air induction, so I pay really close attention to CHT's. Sometimes the temps are fine at WOT, but a higher percentage of the time they're not. You can see the numbers, they're almost perfect.... they wouldn't be if I was WOT. Can't totally tell you why, but after 1,100 hours I have a pretty good handle on what my engine wants and needs. Also I fly by mpg. So even at lower altitudes, if I run several inches less, ususally the mileage is greater. Most pilots don't even mess with the settings, I do. If I gave it those extra 2 inches, sure let's say I pick up from 160kts to 165kts (3% increase), but my fuel burn went from 9.5 to 10.2gph (7.4% increase).
Throttling an engine with the butterfly in the servo results in higher pumping loss than if the engine is free to breath unrestricted. In your example above, why wouldn't you shove the throttle in and grab those two inches of MP, but simply lean back to your 9.5 GPH? All else equal, the engine should produce a bit more power (with less pumping loss), and your CHTs will come down too.
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  #18  
Old 12-04-2019, 09:28 AM
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N941WR N941WR is offline
 
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Quote:
Originally Posted by Capt View Post
Guys please have a read of the article " Flying high and fast" by Ken Krueger, (Google it) makes for some sobering thoughts as a lot of pilots don't understand that VNE at Altitude is NOT based on IAS but TAS.
The Vans designs are very capable of exceeding VNE under certain conditions with fluttering.
Stay safe out there, learn something new everyday -)
His TAS was well below his Vne, so no issues. Notice he listed both IAS and TAS.
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  #19  
Old 12-04-2019, 09:58 AM
rmarshall234 rmarshall234 is offline
 
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You might be interested in reading my buddy Jerry Jackson's account of his round trip transcontinental record setting trip in his RV6A.

https://www.amazon.com/Flight-Feral-.../dp/1453574166
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  #20  
Old 12-04-2019, 02:07 PM
scsmith scsmith is offline
 
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To the OP - thanks for sharing in a later post what engine you have. Your initial post made my heart stop. Sure, the ground speed is great because of the wind, but your IAS and TAS would be unheard-of for a normally aspirated 4 cyl Lyc. at "half throttle and 2230 RPM".

And I agree with Toobuilder - as long as you can run smoothly LOP, you should be able to open the throttle and lean the mixture to the same fuel flow, and get the same CHT, and probably go a little bit faster.
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