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Steve,
Try it in flight as there is a great deal of difference when you are moving
forward at best glide speed as opposed to sitting on the ground.
The flight test is to show yourself the difference in descent rate when the
engine rpm is being turned by the prop at flat and coarse
pitch and best glide speed is maintained.
Scott Krueger
In a message dated 8/20/2013 6:19:39 A.M. Central Daylight Time,
n5276j@aol.com writes:
I'm not so sure at idle power in flight one can pull the prop
back(coarse) that much. Just try changing rpm's at low rpm's during
run-up . I have to be at around 16-1800 to get the prop to cycle at
run-up. Oil pressure play's a big part of the governor's ability to move the
prop. While at idle power one may have high enough oil pressure but surly not
enough volume as 1800 + RPM. There will be oil leakage around the front
main bearing going to the prop. Off field landings or a return to
airport is most likely loss of power of some sort ( low rpm) wind
milling prop.
Most single engine controllable props are pressure to increase pitch,
feathering props are pressure to decrease pitch, unless they are
electric.
I may be wrong but that's the way I understand it.
Steve Alderman N25SA 360
-----Origiso
sure al Message----- From: Robert R Pastusek
<rpastusek@htii.com> To: Lancair Mailing List
<lml@lancaironline.net> Sent: Mon, Aug 19, 2013 3:18 pm Subject:
[LML] Re: Fw: [LML] Re: FW: [LML] Flaps on take-off?
Wolfgang,
My MT prop/governor does not work as you describe below. Specifically, if
the engine is turning (with oil pressure), I can control RPM within the
mechanical stop limits built into the prop hub, and total power/drag. Idle
power/min RPM/120 KIAS glide gives me 600-650 RPM; Max RPM in that
configuration gives about 2600 RPM, and the drag increase is significant.
At a bit above idle power, max
RPM is limited to 2700 by the governor, all the way up to max power. Min RPM
is maintained as power is added…for a while…but I’ve never gone much above
idle power. with the prop at min RPM…hard on the engine…and it’s not a useful
datapoint, but I suspect it will maintain 650 RPM
through full power??
Bob
Where did
the 320 and 172 information come from ?
Fixed pitch
props will continue to windmill but what about constant speed ? - - I haven't
tried this with a non-responsive, non seized engine.
The next
question is what is the blade angle, resulting from a wind driven constant
speed propeller, for the "max" rpm and "min" rpm lever
positions.
The control
loop gain will be "adverse" in that scenario (wind driven vs shaft
driven).
. . . in the
wind driven mode - as the rpm decreases - the pitch is made to go flatter
- making the rpm decrease more - - -
After
consulting with H&S Prop Shop here in Michigan, the light goes
on.
It does
not matter where the RPM lever is set.
With a
non-responsive engine, the blades will go to the minimum pitch set by the
physical stop in the prop hub,
. . .
typically 10-15 degrees depending on setup for the particular
installation.
Now a
feathering prop is a different ball game . . .
-----
Original Message -----
Sent: Sunday, August 18, 2013 10:53
AM
Subject: Re: [LML] Fw: [LML] Re: FW: [LML]
Flaps on take-off?
See the
diagram for drag from wind milling and fixed prop. Hartzell CS prop
for 320 flat pitch is 12 and coarse is 40 degrees.
Base
diagram from Aeronautics for Naval Aviators.
In a
message dated 8/18/2013 9:45:25 A.M. Central Daylight Time, Wolfgang@MiCom.net
writes:
But . .
. when you added power, didn't you also increase the prop rpm
?
Makes me
wonder . . . in gliders we modulate drag with spoilers . . . how much drag
off the propeller disk can be modulated by using the prop rpm control
?
. . .
but then again . . . if the engine is ceased . . . the spring in the prop
hub makes the blades go flat pitch . . . maximum drag !
-----
Original Message -----
Sent: Thursday, August 15, 2013 9:39
PM
Subject: RE: [LML] Re: FW: [LML] Flaps on
take-off?
Robert,
I suppose you could run out of
gas, but I think the reason for the exercise was to teach the pilot how
far the plane would glide with power off in case he was trying to make a
farmers field in a real emergency.
I think you would be surprised
about the feathered prop. I was trying to change my landing
technique the other day by changing the prop to a coarse setting while
in the pattern and locking it in that setting. I had to give it up
because when the plane got into ground effect, it just glided the entire
length of the runway and would not stop flying! Then when I added
power to do a go around, the plane didn’t want to fly because of the
lack of power from the coarse prop.
I was trying this because I
didn’t think I liked the fact that the plane would slow down so fast
with the prop in fine pitch when I pulled the power back. I have
now decided that I like it fine! :>)
B2
Bill,
What you describe is certainly a
possible scenario – actually that sounds like my typical arrival.
With the engine pulled back to 10-12” and a windmilling prop the decent
rate should be similar zero power and a feathered prop.
But how likely is an engine that
fails in the close pattern after a cross-country flight? More
likely something would go afoul enroute, when the pilot could select a
landing spot and arrive 2000 ft above it. If not able to arrive
2000 ft agl – choose an alternate spot.
Just my couple lira . . .
Robert
Robert,
You should try it under
conditions that are more likely to be the case.
Descend to pattern altitude, 1000
ft AGL, slow to pattern speed, and idle the engine abeam the numbers and
see if you can make it
I recommend you idle the engine
and not kill it, because I would be surprised if you do make it. I
also don’t recommend you coarse pitch the prop since you may need to add
power for the go around.
Bill
Bill,
I practiced that maneuver with a
Lancair company pilot flying my ES-P and found it a non-event.
Overhead upwind at 2000 ft agl
and slowing to pattern speed in the turn.
No flaps until over the fence
then deployed everything and aimed for 1/3 down the runway.
I realize the IV would take
different speeds but it should still be do-able with a little
practice.
Robert
ES-P N301ES
That seems a scenario where you
would be in better shape with the flaps up. You very well might
make the runway. With flaps down, you likely would not and it
would be very dangerous to try and retract them. With the high
wing loading that all the Lancairs have, they are flying bricks with no
power. I think almost nobody makes the approach to land with no
power.
Remember way back in primary
training when the instructor had you remove power abeam the numbers and
make the landing without having to add power? Does anyone practice
that maneuver with their Lancair?
Bill B
Matt, I agree with the others
that w's insults are inexcusable, but I must ask a
question.
What do you do if your low over
the departure end of the runway and the engine quits?
1. Land at high speed flaps
up.
2. Lower the flaps and
deal with the big trim and pitch change while making all the other
decisions and actions required in parallel.
----- Forwarded Message -----
From: "marv@lancair.net" <marv@lancair.net>
To:
lml <lml>
Sent: Monday, August 12, 2013 4:02
PM
Subject: [LML] Re: Flaps on take-off?
Posted for Matt
losangeles <mattinlosangeles@yahoo.com>:
>
I feel much safer adding 5 knots or so on the ground before I lift off
so I
>don't have to mess with trim when I am low to the ground. I
could see a
>scenario where I take off IFR and I am immediately
handed off to departure
>control while I am putting the flaps up.
They tell me to do something the
>requires me to look at my map
and the next thing you know, while distracted,
> I am at an
unusual attitude really close to the ground. When I am down low
>like that I want to make sure if I am distracted it isn't a
problem, the
>plane just keeps on climbing along at Vy or
so.
>
> I also would guess if you use flaps on take
off, this adds drag and slows
>your rate of climb (I have
not tested this). I am able to be at Vy a couple
>seconds
after take off and I am going to get to a safer altitude before the
>guy using flaps (again, this is my guess since I have not tested
the two
>scenarios).
>
> Another thing. It is
an experimental aircraft. As it states on the
>EAA, "There
is no FAA approved flight manual or POH for experimental
>aircraft, nor is there a TC".
>
> Ohh, what about those reno racer Legacy
aircraft that have just bonded thier
>flaps in place so they
can't go down in order to eliminate the drag of the
>hindges. I
guess they are not flying those aircraft the way they were meant
>to be flown. You could argue they are reno racers I
suppose. It is also
>likely they are using those planes the other
51 weeks out of the year to fly
>all over the place and those
planes don't seem to be crashing on takeoff.
>
> "I
believe everyone would agree that flaps do add a margin of
safety"
> I personally consider myself part of everyone and
I don't agree that flaps
>do in fact add a margin of safety on
take off. I use them on landing so I can
>see out the window and
out of habit I suppose. If the speed you land at makes
>such
a difference, then the best thing to be doing is flying a plane that
>lands at a slower speed.
>
> Perhaps if we
were all 100 hour pilots, blindly following the POH makes
>sense.
It is funny, I remember having this EXACT same argument on a Mooney
>board. I used to take off without flaps when I had a Mooney and
I heard the
>same thing there. Follow the POH explicitly or
you are completely reckless
>and should have your license taken
away. At least those Mooney guys had a
>point. That was a
certified aircraft with a POH that said to take off with
>flaps.
>
> Something else to consider, if
flaps are so critical to flight on our
>planes, why on earth
don't they have a back up system to ensure they always
>go down
when needed like our landing gear has? My guess is because the plane
>will fly just fine without them.
>
>
Matt
>
>
> ________________________________
>
From: Art Jensen <flycassutts@yahoo.com>
>
To: lml@lancaironline.net
>
Sent: Monday, August 12, 2013 1:46 PM
> Subject: [LML] Re: To
Marv
>
> Maybe Wolfgang was short on political
correctness, but the truth remains
>that if you cannot or do not
fly the plane as it was meant to be flown then
>you should not be
flying that plane.
>
> I believe everyone would agree that
flaps do add a margin of safety and
>should be used for take-off
and landing as per your POH and I believe every
>instructor
giving training in a Lancair would agree. If an instructor
>reading this disagrees, please share why you disagree with
me.
>
> Art
>
> Sent from Yahoo! Mail for
iPad
>
>
>
________________________________
> From: steve <n5276j@aol.com>; To: <lml@lancaironline.net>; Subject:
> [LML] Re: To Marv Sent: Mon, Aug 12, 2013
5:39:28 PM
> I second your post. I am
surprised by the comment.
>
> steve alderman
N25SA 360
>
> .
> -----Original Message-----
From: Claudette Colwell <colwell.ch@gmail.com>
>To: lml <lml@lancaironline.net> Sent:
Mon, Aug 12, 2013 5:43 am Subject:
>[LML] To
Marv
> It is very regretful the comment from Wolfgang
apparently directed to Matt
>appeared on the LML. This has
always been a constructive exchange of
>information and
ideas. That type of personal comment is not in keeping with
>the spirit of cooperative sharing of information.
>
> Claudette -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html
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