Today's Message Index:
----------------------
1. 04:02 AM - Re: Effects of Flaps and Ailerons on Pitch Trim (Peter Zutrauen)
2. 04:09 AM - Re: Effects of Flaps and Ailerons on Pitch Trim (Peter Zutrauen)
3. 06:26 AM - Re: Effects of Flaps and Ailerons on Pitch Trim (Raimo Toivio)
4. 12:59 PM - Re: Effects of Flaps and Ailerons on Pitch Trim (glenn crowder)
5. 12:59 PM - Effect of flaps and ailerons on pitch trim (Fergus Kyle)
6. 01:02 PM - Test pilot wanted for the PH-DIY (Frans Veldman)
7. 02:04 PM - Re: Test pilot wanted for the PH-DIY (GRAHAM SINGLETON)
8. 02:35 PM - Re: Effects of Flaps and Ailerons on Pitch Trim (GRAHAM SINGLETON)
9. 02:35 PM - Re: Test pilot wanted for the PH-DIY (GRAHAM SINGLETON)
10. 03:23 PM - Re: Effects of Flaps and Ailerons on Pitch Trim (rparigoris)
Message 1
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| Subject: | Re: Effects of Flaps and Ailerons on Pitch Trim |
Hi Frans etal,
OK, ok, I believe I have figured out what's going on with the upward trim
tab in cruise.
The when the anti-servo trim tab is *trimmed* out of the neutral position,
then the 'zero stick force' angle of incidence of the tailplane wrt to the
airflow is changed. When the trim tab is protruding *up* (thus driving the
trailing edge downward), I had thought this configuration was providing
*lift* to the tail. It was this simplistic interpretation which was
confusing me. My bad. :-P
So, how does the following sound to all the aerodynamicists out there? When
one considers the tailplane&trim tab combination as a "symmetrical airfoil
wing with flap", then moving the trimtab off-center is effectively adding
camber to the tailplane 'wing' and making the airfoil no longer symmetrical.
In fact, moving the trimtab *up* results in an inverted camber (traditional
wing upside down), thus generating a downward lift vector - and the stars
are again all in proper alignment.
The faster one cruises, then the more camber is required to provide more
downforce to counter-act the main-wing lift pitch, thus more trim tab.
I was/am not speaking of the anti-servo function of the tab, which I agree
fully is driven in the same direction as the stick to augment/provide the
(otherwise negligible flying-tail) stick forces to give proper speed-related
feedback and make the tailplane less prone to flutter - that function is
easy to visualize.
Cheers,
A happy that things now make sense again,
Pete
A239
On Mon, Apr 12, 2010 at 8:28 PM, Frans Veldman <frans@privatepilots.nl>wrote:
>
> On 04/13/2010 01:19 AM, Peter Zutrauen wrote:
>
> > that was my understanding as well - but when trimmed for cruise,
> > wouldn't the anti-servo/trim-tab be required to portrude *downwards* to
> > drive the trailing edge of the tailplane *up*
>
> Read again what you just said. If the trailing edge of the tailplane
> moves up, the trim tab moves up even more. It *always* goes back to the
> same stabile position, regardless of trim setting. The only difference
> is that this stabile position is achieven by a different tailplane
> incidence. This is how it works: you trim it down, it drives the
> tailplane up, this will take the trim tab up even more, counteracting
> what you just did... and the nett effect is that the tailplane's
> trailing edge has moved up. This is how a anti-servo tab works.
>
> > to result in the
> > equivalent of pulling back on the stick,
>
> Pulling back on the stick is not the equivalent. If you pull on the
> stick, the trim tab won't revert to its stabile aerodynamic position...
> and that is why you need to keep pulling on the stick, to counteract the
> forces on the trim tab.
>
> > to have the tailplane produce
> > the required downward force on the tail?
>
> Actually, it is not a trim tab, but an anti-servo trim tab. It works
> differently.
>
> > All the pics I've seen show the trimtab portruding *up*, ie, trim
> > foward stick..... no?
>
> The *only* conclusion you can draw from the trimtab protruding up, is
> that its stabile position is upwards relative to the tailplane. This
> will remain the same for all trim settings. If you change the trim, the
> only nett effect is that the tailplane will move to a different
> incidence... but the trim tab will remain at the same position. Play
> with it on the ground, until you see what's happening.
>
> Frans
>
>
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| Subject: | Re: Effects of Flaps and Ailerons on Pitch Trim |
Further to my previous post, if one were to optimize the airfoil of the
flying tail to minimize drag (which I had incorrectly presumed Don D had
done), then the tailplane would have had a very slight inverted camber,
calculated such that no trim-tab offset would have been required at the
"target" cruise speed.
Cheers,
Pete
On Tue, Apr 13, 2010 at 7:00 AM, Peter Zutrauen <peterz@zutrasoft.com>wrote:
> Hi Frans etal,
>
> OK, ok, I believe I have figured out what's going on with the upward trim
> tab in cruise.
>
> The when the anti-servo trim tab is *trimmed* out of the neutral position,
> then the 'zero stick force' angle of incidence of the tailplane wrt to the
> airflow is changed. When the trim tab is protruding *up* (thus driving the
> trailing edge downward), I had thought this configuration was providing
> *lift* to the tail. It was this simplistic interpretation which was
> confusing me. My bad. :-P
>
> So, how does the following sound to all the aerodynamicists out there?
> When one considers the tailplane&trim tab combination as a "symmetrical
> airfoil wing with flap", then moving the trimtab off-center is effectively
> adding camber to the tailplane 'wing' and making the airfoil no longer
> symmetrical. In fact, moving the trimtab *up* results in an inverted camber
> (traditional wing upside down), thus generating a downward lift vector - and
> the stars are again all in proper alignment.
>
> The faster one cruises, then the more camber is required to provide more
> downforce to counter-act the main-wing lift pitch, thus more trim tab.
>
> I was/am not speaking of the anti-servo function of the tab, which I agree
> fully is driven in the same direction as the stick to augment/provide the
> (otherwise negligible flying-tail) stick forces to give proper speed-related
> feedback and make the tailplane less prone to flutter - that function is
> easy to visualize.
>
> Cheers,
> A happy that things now make sense again,
> Pete
> A239
>
>
> On Mon, Apr 12, 2010 at 8:28 PM, Frans Veldman <frans@privatepilots.nl>wrote:
>
>>
>> On 04/13/2010 01:19 AM, Peter Zutrauen wrote:
>>
>> > that was my understanding as well - but when trimmed for cruise,
>> > wouldn't the anti-servo/trim-tab be required to portrude *downwards* to
>> > drive the trailing edge of the tailplane *up*
>>
>> Read again what you just said. If the trailing edge of the tailplane
>> moves up, the trim tab moves up even more. It *always* goes back to the
>> same stabile position, regardless of trim setting. The only difference
>> is that this stabile position is achieven by a different tailplane
>> incidence. This is how it works: you trim it down, it drives the
>> tailplane up, this will take the trim tab up even more, counteracting
>> what you just did... and the nett effect is that the tailplane's
>> trailing edge has moved up. This is how a anti-servo tab works.
>>
>> > to result in the
>> > equivalent of pulling back on the stick,
>>
>> Pulling back on the stick is not the equivalent. If you pull on the
>> stick, the trim tab won't revert to its stabile aerodynamic position...
>> and that is why you need to keep pulling on the stick, to counteract the
>> forces on the trim tab.
>>
>> > to have the tailplane produce
>> > the required downward force on the tail?
>>
>> Actually, it is not a trim tab, but an anti-servo trim tab. It works
>> differently.
>>
>> > All the pics I've seen show the trimtab portruding *up*, ie, trim
>> > foward stick..... no?
>>
>> The *only* conclusion you can draw from the trimtab protruding up, is
>> that its stabile position is upwards relative to the tailplane. This
>> will remain the same for all trim settings. If you change the trim, the
>> only nett effect is that the tailplane will move to a different
>> incidence... but the trim tab will remain at the same position. Play
>> with it on the ground, until you see what's happening.
>>
>> Frans
>>
>>
>>
>>
>>
>
--
"A man is not old until his regrets take the place of his dreams. "
Message 3
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| Subject: | Re: Effects of Flaps and Ailerons on Pitch Trim |
Glenn,
that makes sense.
That is why when flying faster pilot have to push stick forward to keep
altude.
Tailplane=B4s trailing edge is moving then down and tailplane=B4s
negative AoA goes slightly smaller.
Tab=B4s anti-servo function moves tabs even more down to generate (more)
force to the pilot=B4s hand. To eliminate that force pilot trims "nose
down" = trim tabs move a little upp to keep tailplane=B4s trailing
edges down = where they should be to keep to maintain level flight.
Without anti-servo function I assume there would be still pitch forces
but only about 1/3-1/2 (look at the torque tube position in relation
with tailplanes)?
When cruis=EDng levelled and with power lever in it=B4s fore position,
XRT needs almost full nose down trimming.
Raimo OH-XRT
----- Original Message -----
From: glenn crowder
To: europa-list@matronics.com
Sent: Tuesday, April 13, 2010 6:54 AM
Subject: RE: Europa-List: Effects of Flaps and Ailerons on Pitch Trim
OK Pete - the tailplane is ALWAYS pushing down at all airspeeds but at
higher airspeeds the wing is at a very low angle of attack. As the
airspeed goes up, the
aerodynamic forces on all control surfaces (ailerons, rudder,
tailplane) go up by the
SQUARE of airspeed. This is why you cannot give full control
deflection at VNE, the
control surfaces will depart the aircraft. So when the wing goes to a
very low angle
of attack, the tail must also. The tail is still flying at a negative
angle of attack but
it is very small. However this small negative angle of attack is
generating a lot of
positive CM because of the high airspeed. To get this slightly
negative angle of attack
at a high airspeed requires a lot of force and this is generated by
the UP position of
the trimtab forcing the trailing edge of the tailplane DOWN. The trim
tab controls the
angle of attack of the tail (always negative but less negative at high
speed), the
anti servo system keeps the tail at the set angle of attack. Other
factors come into
play here such as the angle of relative airflow from the wing
downwash. The tail
may look as though it has a positive angle of attack but because of
the wing downwash, the relative airflow is actually hitting it from
above This angle becomes less at high speeds but the forces go up with
the square of airspeed.
at high speeds
-------------------------------------------------------------------------
-----
Date: Mon, 12 Apr 2010 19:19:06 -0400
Subject: Re: Europa-List: Effects of Flaps and Ailerons on Pitch Trim
From: peterz@zutrasoft.com
To: europa-list@matronics.com
Hi Glenn,
that was my understanding as well - but when trimmed for cruise,
wouldn't the anti-servo/trim-tab be required to portrude *downwards* to
drive the trailing edge of the tailplane *up* to result in the
equivalent of pulling back on the stick, to have the tailplane produce
the required downward force on the tail?
All the pics I've seen show the trimtab portruding *up*, ie, trim =
foward stick..... no?
Still confused,
Pete
A239
On Mon, Apr 12, 2010 at 2:41 PM, Glenn Crowder <gcrowder2@hotmail.com>
wrote:
<gcrowder2@hotmail.com>
The airfoil of the wing of any aircraft with a non symmetrical
section will produce a negative pitching moment (-cm) around the
aerodynamic center of the wing. This means that without the tailplane
producing an equal but opposite moment the acft will pitch over into a
vertical dive. The all flying tailplane on the Europa has no fixed
angle of incidence so to produce an opposing positive torque moment to
the wings negative one the trim tab must be held out of plane. At
higher speeds then the tailplane must provide greater downforce then
requiring even more trim tab offset. We have to pay a small drag
penalty to achieve a level trim condition in cruise flight. This
penalty can be reduced somewhat by loading the acft towards the aft cg
limits requiring less trim tab offset reducing the downforce the
tailplane must produce to maintain level flight.
The tailless flying wing derives it's pitch stability due to the
outer portions of the wing being reflexed up to produce that necessary
positive pitching moment but also introduces that small drag penalty
again. There is no free lunch in aerodynamics! Every desireable
aerodynamic quality (like pitch stability) has a price that must be
paid.
Glenn
Fred Klein <fklein@orcasonline.com> wrote:
>
>On Apr 12, 2010, at 6:24 AM, david miller wrote:
>
>> I think that for most efficient flight the incidence of the wing
and
>> tail should be such that at cruise there is no up or down trim on
>> the elevator or all flying tail.
>
>Fascinating discussion...as a non-aerodynamicist, I can't resist
the
>temptation to add a comment...
>
>I've always understood that the elevator or an all-flying tail
>(horizontal tail plane) has a "job"...namely, to exert a force,
either
>up or down, in order to balance the lift of the wing and stabilize
the
>flight path of a normally configured aircraft (i.e., not a canard
>type). To do this "job" requires "work"; the tail plane is never
>neutral. And w/ our Europae...with it's trim tabs acting in
>opposition to the all-flying tail plane thru a direct mechanical
>connection...whenever the tail plane is doing its job (at whatever
>angle of incidence), the trim tabs will be doing their job as well
>(that of counterbalancing forces on the tailplane), and will
>necessarily be raised or lowered w/ reference to the tailplane.
>
>Of course if this explanation is correct, one might ponder the
>aerodynamics of my tail-less biplane...pix below.
>
>Fred
>
>
>
>
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| Subject: | Effects of Flaps and Ailerons on Pitch Trim |
Hi Pete - yes=2C it is totally valid to think of it that way. With the
trim tab set to neutral=2C the tailplane is designed to maintain a negative
angle of attack sufficient to balance the negative pitching moment of the
wing at typical "in the pattern speeds". This angle corresponds to the mat
ching fillets molded into the fuselage sides at the tail.
At low to moderate airspeeds=2C the tailplane needs a sizeable negative a
ngle of attack to create enough downforce at the tail to force the leading
edge of the wing up to it's required angle of attack. Without the tail pus
hing down thus raising the wing leading edge up=2C the wing becomes lazy an
d does'nt want to fly=2C trying to reduce the angle of attack. This is tha
t negative pitching moment that all non symmetrical airfoils have. This is
easily noticed in a stall situation=2C with nearly all the UP elevator bein
g required to hold the high angle of attack.
Now when we want to go fast=2C requirements start to change. We want the
wing to assume a very low angle of attack because as the speeds go up=2C t
he lift
on the wing goes up by the SQUARE of airspeed. Reducing the angle of attac
k
reduces the lift of the wing and also the induced drag. But since we are g
oing
much faster=2C the wing is creating the same amount of lift sufficient to m
aintain a
steady cruising altitude. But at this higher airspeed the tailplane is sti
ll trying to maintain the high negative angle of attack it was designed to
maintain at low to moderate airspeeds. So now we have to do something to r
educe the extremely high downforce the tail is trying to generate. This is
achieved by reducing the negative angle of attack of the tailplane. We n
eeded a large negative angle for takeoff and pattern work but now we need a
much smaller negative angle.
To reduce this negative angle of attack we then apply DOWN trim which rai
ses the trimtab UP=2C which then forces the trailing edge of the tailplane
DOWN=2C which then reduces the negative angle of attack to a much smaller v
alue=2C reducing the downforce generated by the tailplane. It is still pro
ducing a large amount of downforce though as the high airspeed is creating
a lot of force with only a small negative angle of attack (the airspeed squ
ared thing).
The aircraft COULD have been designed to maintain this high speed slightl
y negative angle of attack with neutral trim tab to minimize drag. However
if this had been done the design would have required HUGE trimtabs trimmed
DOWN at lower speeds to then force the trailing edge of the tailplane UP t
hat would then create a large negative angle of attack on the tailplane req
uired to balance the wing at lower airspeeds.
Subject: Re: Europa-List: Effects of Flaps and Ailerons on Pitch Trim
From: peterz@zutrasoft.com
Further to my previous post=2C if one were to optimize the airfoil of the f
lying tail to minimize drag (which I had incorrectly presumed Don D had don
e)=2C then the tailplane would have had a very slight inverted camber=2C ca
lculated such that no trim-tab offset would have been required at the "targ
et" cruise speed.
Cheers=2C
Pete
On Tue=2C Apr 13=2C 2010 at 7:00 AM=2C Peter Zutrauen <peterz@zutrasoft.com
> wrote:
Hi Frans etal=2C
OK=2C ok=2C I believe I have figured out what's going on with the upward t
rim tab in cruise.
The when the anti-servo trim tab is *trimmed* out of the neutral position
=2C then the 'zero stick force' angle of incidence of the tailplane wrt to
the airflow is changed. When the trim tab is protruding *up* (thus driving
the trailing edge downward)=2C I had thought this configuration was provi
ding *lift* to the tail. It was this simplistic interpretation which was c
onfusing me. My bad. :-P
So=2C how does the following sound to all the aerodynamicists out there? W
hen one considers the tailplane&trim tab combination as a "symmetrical airf
oil wing with flap"=2C then moving the trimtab off-center is effectively a
dding camber to the tailplane 'wing' and making the airfoil no longer symme
trical. In fact=2C moving the trimtab *up* results in an inverted camber (t
raditional wing upside down)=2C thus generating a downward lift vector - an
d the stars are again all in proper alignment.
The faster one cruises=2C then the more camber is required to provide more
downforce to counter-act the main-wing lift pitch=2C thus more trim tab.
I was/am not speaking of the anti-servo function of the tab=2C which I agre
e fully is driven in the same direction as the stick to augment/provide the
(otherwise negligible flying-tail) stick forces to give proper speed-relat
ed feedback and make the tailplane less prone to flutter - that function is
easy to visualize.
Cheers=2C
A happy that things now make sense again=2C
Pete
A239
On Mon=2C Apr 12=2C 2010 at 8:28 PM=2C Frans Veldman <frans@privatepilots.n
l> wrote:
On 04/13/2010 01:19 AM=2C Peter Zutrauen wrote:
> that was my understanding as well - but when trimmed for cruise=2C
> wouldn't the anti-servo/trim-tab be required to portrude *downwards* to
> drive the trailing edge of the tailplane *up*
Read again what you just said. If the trailing edge of the tailplane
moves up=2C the trim tab moves up even more. It *always* goes back to the
same stabile position=2C regardless of trim setting. The only difference
is that this stabile position is achieven by a different tailplane
incidence. This is how it works: you trim it down=2C it drives the
tailplane up=2C this will take the trim tab up even more=2C counteracting
what you just did... and the nett effect is that the tailplane's
trailing edge has moved up. This is how a anti-servo tab works.
> to result in the
> equivalent of pulling back on the stick=2C
Pulling back on the stick is not the equivalent. If you pull on the
stick=2C the trim tab won't revert to its stabile aerodynamic position...
and that is why you need to keep pulling on the stick=2C to counteract the
forces on the trim tab.
> to have the tailplane produce
> the required downward force on the tail?
Actually=2C it is not a trim tab=2C but an anti-servo trim tab. It works
differently.
> All the pics I've seen show the trimtab portruding *up*=2C ie=2C trim
> foward stick..... no?
The *only* conclusion you can draw from the trimtab protruding up=2C is
that its stabile position is upwards relative to the tailplane. This
will remain the same for all trim settings. If you change the trim=2C the
only nett effect is that the tailplane will move to a different
incidence... but the trim tab will remain at the same position. Play
with it on the ground=2C until you see what's happening.
Frans
--
"A man is not old until his regrets take the place of his dreams. "
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| Subject: | Effect of flaps and ailerons on pitch trim |
I digress.......
I can see the cogs of a thousand minds cranking 'round. - and I'm scared to
take part.....
First of all, definition: I learned early that the angle between the
wing centreline and the stabilizer centreline was called the Rigger's Angle
of Incidence. In aircraft of the day, this was fixed by the designer. Thus,
the trim tab had its effect to reposition the elevator and thus change the
shape of the horizontal tail. This in turn revised the up- or down-tendency
of the horizontal tail section. What happened to the R'sA of I,? Nothing..
Now, put in the F86 'flying tail' which we have - and its
confusions, and I doubt we are all talking about the same thing.
Modern machines divine the proper trim position every second and little
motors are forever humming away to keep the aircraft in permanent but
adjustable trim - thus simplifying. the task for monkeys. Push on the stick
and the whole argument goes out the door. I leave it to others.
One question on a qualification exam (to get promoted) said:
"You are flying the Chief of the Air Staff who is in the back seat of your
Harvard (T-6, SNJ). He does not answer you. You look around and the seat is
empty. What is the first thing you do?"
The 'official' answer was "trim for change in C of G". I lost, like
the majority, most of whom were making MayDay calls. But the correct reply
was "I did that instantly when he left because my machine was always in
trim". I appealed, won my case and graduated to Flying Officer. They never
did find the CAS.
Cheers, Ferg
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| Subject: | Test pilot wanted for the PH-DIY |
Hi everyone,
Who has followed this forum recently knows that the PH-DIY is for some
time ready to fly.
So far we have not been lucky with our test pilots. We had one very good
option in the Netherlands, but his wife didn't like the idea at all.
Ivan Shaw doesn't answer and apparently is on a cruise (and after his
return probably dealing with a huge backlog). Andy Draper is willing to
do it, but his agenda appears to be overloaded. Take the weather into
the equation, and it is almost impossible to make an appointment and
reserve a flight for him to come over.
So, we are now sitting under a bright blue sky, next to a shiny new
airplane, while other airplanes are passing over our house, unable to
fly, and not really knowing what to do now.
It is tempting to Do It Yourself, but as a low timer with no experience
in an Europa this wouldn't be the wisest thing to do, so far we managed
to resist the temptation.
Does anyone of you know a capable test pilot? It doesn't has to be an
official test pilot, but someone with good experience in Europa's and
other planes, and knowing how to conduct a first flight.
We have options here to take the initial lessons in our Europa, so what
we need is only someone with a flexible agenda who is capable and
willing to do the first flight.
Rules are easy here: As far as the government is concerned, anyone with
a valid JAR PPL is entitled to fly the PH-DIY. There are no restrictions
in time, distance or weight.
Of course we will pay for expenses and time.
Ilona & Frans
(From the North of The Netherlands)
Message 7
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| Subject: | Re: Test pilot wanted for the PH-DIY |
Frans=0AIvan is home any day now, I expect we will talk soon so I will ask
him=0AGraham=0A=0A=0A=0A=0A=0A________________________________=0AFrom: Fran
s Veldman <frans@privatepilots.nl>=0ATo: europa-list@matronics.com=0ASent:
Tuesday, 13 April, 2010 18:51:36=0ASubject: Europa-List: Test pilot wanted
@privatepilots.nl>=0A=0AHi everyone,=0A=0AWho has followed this forum recen
tly knows that the PH-DIY is for some=0Atime ready to fly.=0A=0ASo far we h
ave not been lucky with our test pilots. We had one very good=0Aoption in t
he Netherlands, but his wife didn't like the idea at all.=0AIvan Shaw doesn
't answer and apparently is on a cruise (and after his=0Areturn probably de
aling with a huge backlog). Andy Draper is willing to=0Ado it, but his agen
da appears to be overloaded. Take the weather into=0Athe equation, and it i
s almost impossible to make an appointment and=0Areserve a flight for him t
o come over.=0A=0ASo, we are now sitting under a bright blue sky, next to a
shiny new=0Aairplane, while other airplanes are passing over our house, un
able to=0Afly, and not really knowing what to do now.=0A=0AIt is tempting t
o Do It Yourself, but as a low timer with no experience=0Ain an Europa this
wouldn't be the wisest thing to do, so far we managed=0Ato resist the temp
tation.=0A=0ADoes anyone of you know a capable test pilot? It doesn't has t
o be an=0Aofficial test pilot, but someone with good experience in Europa's
and=0Aother planes, and knowing how to conduct a first flight.=0A=0AWe hav
e options here to take the initial lessons in our Europa, so what=0Awe need
is only someone with a flexible agenda who is capable and=0Awilling to do
the first flight.=0ARules are easy here: As far as the government is concer
ned, anyone with=0Aa valid JAR PPL is entitled to fly the PH-DIY. There are
no restrictions=0Ain time, distance or weight.=0A=0AOf course we will pay
for expenses and time.=0A=0AIlona & Frans=0A=0A(From the North of The Nethe
-========================
==================
Message 8
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| Subject: | Re: Effects of Flaps and Ailerons on Pitch Trim |
Maybe I can add a bit more confusion?=0AIn fact the tail plane pivot is not
at the neutral point, it's slightly forward I think (Mike?) You're right t
hat the tab is anti balance.=0AWith symmetrical sections aerodynamic centre
doesn't move, that's why all flying tails are usually symmetrical. (afaik)
Add the effect of the displaced tab and you have camber so the section wil
l now provide lift at zero AoA. ie tailplane in trail? This lift is just e
nough to balance the wing pitching moment. Increase speed and you get more
lift so nose will pitch up. Speed reduces again etc. =0AGraham=0A=0A=0A=0A
=0A________________________________=0AFrom: Frans Veldman <frans@privatepil
ots.nl>=0ATo: europa-list@matronics.com=0ASent: Monday, 12 April, 2010 19:5
1:09=0ASubject: Re: Europa-List: Effects of Flaps and Ailerons on Pitch Tri
s.nl>=0A=0AOn 04/12/2010 08:06 PM, Peter Zutrauen wrote:=0A=0A=0A=0AThe onl
y thing I'm troubled with is that the stable rest position of the=0Atailpla
ne plus trim tab is not when they are perfectly lined out in=0Arelation to
each other.=0A=0AMaybe, just maybe, this may have something to do with the
fact that the=0Ahinges are on the upper side of the tailplane, rather than
in the=0Acenter. The forces acting on the lower side have more leverage tha
n the=0Aforces acting on the upper side, hence the stable position of the t
rim=0Atab where all forces are cancelled out, is slightly up.=0A=0AThe more
I think about this, the more I think that this is the reason=0Awhy we alwa
ys see a trim tab up position.=0A=0AAny comments about this hypothesis?=0A
=0AFrans=0A
Message 9
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| Subject: | Re: Test pilot wanted for the PH-DIY |
Frans =0AWhat about Henk or Bart, (Roelofs) sorry about the spelling, or Ro
b Zeelenberg, All with lots of experience. Rob did his own first flight the
n let me do an "official" first for him. =0AGraham=0A=0A=0A=0A=0A__________
______________________=0AFrom: Frans Veldman <frans@privatepilots.nl>=0ATo:
europa-list@matronics.com=0ASent: Tuesday, 13 April, 2010 18:51:36=0ASubje
ct: Europa-List: Test pilot wanted for the PH-DIY=0A=0A--> Europa-List mess
age posted by: Frans Veldman <frans@privatepilots.nl>=0A=0AHi everyone,=0A
=0AWho has followed this forum recently knows that the PH-DIY is for some
=0Atime ready to fly.=0A=0ASo far we have not been lucky with our test pilo
ts. We had one very good=0Aoption in the Netherlands, but his wife didn't l
ike the idea at all.=0AIvan Shaw doesn't answer and apparently is on a crui
se (and after his=0Areturn probably dealing with a huge backlog). Andy Drap
er is willing to=0Ado it, but his agenda appears to be overloaded. Take the
weather into=0Athe equation, and it is almost impossible to make an appoin
tment and=0Areserve a flight for him to come over.=0A=0ASo, we are now sitt
ing under a bright blue sky, next to a shiny new=0Aairplane, while other ai
rplanes are passing over our house, unable to=0Afly, and not really knowing
what to do now.=0A=0AIt is tempting to Do It Yourself, but as a low timer
with no experience=0Ain an Europa this wouldn't be the wisest thing to do,
so far we managed=0Ato resist the temptation.=0A=0ADoes anyone of you know
a capable test pilot? It doesn't has to be an=0Aofficial test pilot, but so
meone with good experience in Europa's and=0Aother planes, and knowing how
to conduct a first flight.=0A=0AWe have options here to take the initial le
ssons in our Europa, so what=0Awe need is only someone with a flexible agen
da who is capable and=0Awilling to do the first flight.=0ARules are easy he
re: As far as the government is concerned, anyone with=0Aa valid JAR PPL is
entitled to fly the PH-DIY. There are no restrictions=0Ain time, distance
or weight.=0A=0AOf course we will pay for expenses and time.=0A=0AIlona & F
=========================0A
======
Message 10
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| Subject: | Re: Effects of Flaps and Ailerons on Pitch Trim |
Another contributing factor to necessary stabilator force required is engine angle.
An easy check would be to trim for normal cruise speed with engine running,
note trim position and measure precise location of stick (string or ruler).
Then kill engine, prefer if you can feather prop, but stopped prop is sufficient,
then with trim in same location and stick brought to precise location see
what speed you achieve. If speed is greater than engine on cruse speed you don't
quite have enough down engine angle (prop end not down far enough) for most
efficiency and vise versa (less speed and too much down engine angle).
On models and full scale having a slight positive nose up pitching is not a bad
thing.
BTW similar technique can be used to dial in CG on a model, motor off trim for
a few MPH over stall, then dive to maneuvering speed and put stick in exact position
it was to achieve trim a few MPH over stall, if it pitches wildly up you
are too nose heavy for most efficiency. Again a slight nose up pitching is desirable
Ron Parigoris
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http://forums.matronics.com/viewtopic.php?p=294111#294111
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