Joined: Jul 20, 2004 Posts: 3701 Location: Birmingham, UK
Posted: Sun Feb 15, 2009 10:28 pm Post subject:
Heliwhore wrote:
No no, it's true. You can even take your hand off the cyclic if you have enough friction on it as well. At times like that, I like to put a brick on the pedals.
Now I bet you're going to tell me you've let down into a field, put the frictions on rotors running and gone to take a pee behind a bush!
Joined: Feb 14, 2008 Posts: 879 Location: Stavanger, Norway
Posted: Sun Feb 15, 2009 10:28 pm Post subject:
Does anyone have a cockpit picture of the R66, would like to see their instrument layout/types. _________________ ATPL(H) IR(H): SK92, AS355, EC120, R22/44
"When the tough gets going, the tough eat haggis!"
Joined: Feb 20, 2008 Posts: 1059 Location: New York
Posted: Sun Feb 15, 2009 10:29 pm Post subject:
WhirlyGirl wrote:
He has recommended that RHC redesign their MAP limit chart based taking into account the carb temperature as opposed to simply calculating it on OAT. Sarah
Sarah,
Does the Robinson have the same limitation on the CAT gauge as does Schweizer 300s.....that it is unreliable below 18' mp?
This could be reason not to base the MAP limit chart on CAT rather than OAT.
Just a thought.
AB _________________ "A Copter Pilot's Life has it's... ups and downs"
Bell 47-206, Schweizer 300/500, Citation 525
Joined: Jul 20, 2004 Posts: 3701 Location: Birmingham, UK
Posted: Sun Feb 15, 2009 10:37 pm Post subject:
R66... sadly not. Haven't seen it in action yet.
To respond to whoever asked about why I might be pulling close to max MAP in the hover, it's not that difficult in a Beta if you're teaching hovering and the stude inadvertently goes a bit heavy on his left boot. I'm only a modest 130lb - I can take full fuel with many of my students and still be well within weight and CofG limits (not that I tend to fill it up to the brim for training), but even with only the main tank full it can on occasions get close to that limit.
Joined: Jul 20, 2004 Posts: 3701 Location: Birmingham, UK
Posted: Sun Feb 15, 2009 10:42 pm Post subject:
afterburner wrote:
Does the Robinson have the same limitation on the CAT gauge as does Schweizer 300s.....that it is unreliable below 18' mp?
This could be reason not to base the MAP limit chart on CAT rather than OAT.
Yes is is unreliable below 18", but I suspect that even on the "new" placard, if it ever does come out I imagine the rule of full carb heat below 18"MAP will still apply.
In the R22 the position of the sensor is not in a good place in relation to the throttle butterfly which adds to the unreliability.
Another tip... if you don't already do so, make checking the carb gauge reading part of your A-Check. Before the first flight of the day it should read the same as OAT. If it reads significantly higher then your reading once the engine is running probably won't be accurate and you may think you're out of the yellow band when you're actually not.
Joined: Feb 20, 2008 Posts: 1059 Location: New York
Posted: Sun Feb 15, 2009 10:57 pm Post subject:
WhirlyGirl wrote:
Another tip... if you don't already do so, make checking the carb gauge reading part of your A-Check. Before the first flight of the day it should read the same as OAT. If it reads significantly higher then your reading once the engine is running probably won't be accurate and you may think you're out of the yellow band when you're actually not.Sarah
Good suggestion for all carb engine helicopters with CAT gauges.
(One of the reasons I only fly the fuel injected models )
Thanks Whirlygirl.
AB _________________ "A Copter Pilot's Life has it's... ups and downs"
Bell 47-206, Schweizer 300/500, Citation 525
Joined: Feb 14, 2008 Posts: 879 Location: Stavanger, Norway
Posted: Sun Feb 15, 2009 11:40 pm Post subject:
The "below 18" MAP" restriction is due to a large pressure differential (and therefor temperature) over the throttle butterfly when at a low power setting. The carb temp sensor is only taking the temp from one side of the butterfly where it is maybe all hunky dorey, however ice may be forming on the opposite side.
This was brought in to force after two R22's both suffered engine failures due to icing when recovering from autorotation in the US.
First one occured, EOL in to field. FI contacted his school and the CFI flew out to the site in another R22, for convenience and time saving he conducted an auto to the same field, upon power recovery the engine stopped, again due to icing.
Both pilots has simply been maintaining carb temp out of the yellow band during the auto.
yeh we looked at that on the robinson safety course - not a problem on the R44 as the temp sensor is other side of the valve _________________ PPL (H)
R22
B206
If it moves i want a go
Joined: Feb 20, 2008 Posts: 1059 Location: New York
Posted: Mon Feb 16, 2009 12:10 am Post subject:
HaggisHunter wrote:
the CFI flew out to the site in another R22, for convenience and time saving he conducted an auto to the same field, upon power recovery the engine stopped, again due to icing.
For convenience and time saving! Your kidding, right? Why would you want to intentionally conduct an auto into a field, unless you are training. Wouldn't a steep approach/confined area approach profile due? and be a safer way to conduct the operation?
I don't think that was a very wise decision on the part of the FI , especially as it turned out. He thought power would be available on the recovery. Surprise! He is lucky he did not slam into the ground.
or am I not understanding the post (again. )
_________________ "A Copter Pilot's Life has it's... ups and downs"
Bell 47-206, Schweizer 300/500, Citation 525
Posted: Mon Feb 16, 2009 12:42 pm Post subject: CAT during 'A' check
I've been taught to look at the CAT during my 'A' check, I even thought about snagging the A/C the other week...
Outside Air Temp Gauge reading 2°C
CAT reading 30°C
Now I know it should be reading 2°C or somewhere very close... I was all for ringing my instructor back in the office when it dawned on me, when was the A/C last flown?
Yup - I'd cracked it by the time I'd opened the cowlings... The engine was still hot from the previous flight hrs before and the carb had heat soaked to the engine block temp!
I continued with the start and watched the CAT shoot downward before the warmth of carb heat raised it back up.
Moral of the story is not to always believe what you see on first inspection - verify with another source if possible.
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