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Propeller thrust question by
xerj
Thrust from a propeller drops as speed increases to a theoretical zero. When
this happens, what is providing the thrust to overcome drag? The forward
momentum of the aircraft?
If so, is it a case of the speed very slightly and imperceptibly dipping
below the zero thrust speed, getting a little...
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November 25th 05 03:12 AM
by Dave S
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Shockwave formation on the wing. Is this diagram correct? by
xerj
On this page, there's an animated diagram (aptly done in shockwave) about
normal shockwave formations:-
http://selair.selkirk.bc.ca/aerodynamics1/High-Speed/Page2c.html
Something confuses me though. As diagrammed, the red pressure wave at the
rear has a low frequency at the front and a high...
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Future of GA piston fuel? by
xerj
If you had to do a bit of crystal ball gazing, what do you think the engines
of the GA fleet will be drinking in 10-15 years time?
The same avgas as today, just much more expensive?
Jet-A in diesel engines?
Something else?
( 1 2)
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Follow up to monster thread below re IAS and TAS and power required... by
xerj
Gettin' a bit confused here. (nothing new in that)
In the big sprawling thread I started down below, there's been a couple of
themes that have come up.
One is that I am pretty sure that for the same IAS (not TAS) at a higher
altitude, more power is required. However, one contributor to the...
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February 5th 07 10:45 PM
by Al G
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January 29th 07 01:08 PM
by Tony
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A question I'm embarrased to ask - earth's spin by
xerj
I was talking about Coriolis effect with someone and he asked me about
planes against or with the earth's spin of around 1000mph at the equator. He
asked why this didn't benefit east to west plane travel timewise and hurt
west to east. I couldn't give him a straight answer, and felt like an...
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climb performance Jet vs Prop by
xerj
Do I have the following right?:-
Jet:-
Vx IAS stays the same as altitude gets higher.
Vy IAS reduces as altitude gets higher.
Both angle and rate of climb lessen as altitude increases.
Prop:-
Vx IAS increases as altitude gets higher.
Vy IAS reduces as altitude gets higher.
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just out of interest: pressure pattern navigation by
xerj
.... when using pressure pattern nav techniques, what's a standard way for
working out groundspeed for flight planning purposes? Do you take the
forecast curved route and divide it up into segments and average it out?
TIA
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From Piper Chieftan manual regarding engines by
xerj
Come across another thing that has puzzled me (big surprise).
Here's a transcript from the manual:
"Under full throttle operations (such as takeoff and climb) the engines of
the aircraft have been adjusted to provide 43 inches of manifold pressure at
seal level and standard temperature. It is...
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December 4th 05 01:24 AM
by xerj
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practical best range application? by
xerj
I understand the theory vis a vis lowest L/D TAS and the power
available/power required chart, but let's say you're in flight in a normally
aspirated prop plane, your destination is blown up, your alternate is
unservicable for some reason or other and you need to stretch the fuel you
have the...
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Anyone flown with an AoA indicator? by
xerj
Was reading an article in an Australian mag about an LED based AoA indicator
in a homebuilt. The author stated that in many ways it "replaced" the AI for
him.
Anyone have experience with them?
( 1 2)
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At the risk of feeding the troll, what IS Skylune's beef? by
xerj
As a relative latecomer to the group, I'm behind the curve on what his basic
argument is.
It's something to do with the relative risks of GA flying isn't it? He
claims that it's actually higher than is admitted or something like that?
TIA.
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October 27th 05 04:56 PM
by alexy
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'nuther question: highest TAS... by
xerj
.... for a normally aspirated piston occurs at sea level and full power, but
for a turbonormalised engine it will be at critical altitude, right?
Thanks in advance.
( 1 2)
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October 19th 05 02:00 PM
by xerj
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Power setting table and best economy/best power... by
xerj
When a power setting table shows a "best economy" and "best power" setting
for a given power level (say 75%) using a given MP and RPM this is just a
starting point, right?
Once the MP and RPM has been set and the leaning done, the actual power
settings would be more like 78% for best power, and...
( 1 2 3)
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Fuel flow and leaning this time by
xerj
Yet another question.
Say you're at altitude and it's time to lean the constant speed engine(s).
You pull back on the mixture control, the EGT starts to go up. The engine
"sounds" more powerful as you do this. The prop might speed up momentarily
until the governor does its stuff and keeps it at...
( 1 2)
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Another thing I'm puzzled about: this time power settings and altitude. by
xerj
OK. These numbers are based on an extract from a power setting table for a
Lycoming 180HP :-
For 55% rated power with a FF of 7.4G/h at SL with an RPM of 2100, the MP
is 20.9.
For 55% rated power with a FF of 7.4G/h at 12,000 ft PA, again with an RPM
of 2100, the MP is 18.2.
I understand (and...
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Hmm. REALLY not understanding circulation by
xerj
Every time I think I have it sort of worked out, I fall in a heap. I've read
through "See How It Flies", but it's still a bit beyond me.
I can understand why a spinning ball would create a circular flow around
itself, but I can't really grasp why a wing would.
Does anyone have a lay explanation...
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September 19th 05 11:32 PM
by xerj
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Hurricane hunters? by
xerj
The site is down at the moment, but if I'm understanding it correctly, do
these guys actually penetrate hurricanes in P3s and Gulfstreams?
Do they go IMC flying into hurricane cloud???
If so, how the hell are they not constantly stalling as they are buffetted
by the turbulence? I'm pretty sure...
( 1 2 3)
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