Today's Message Index:
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1. 03:58 AM - Re: Re: M3X pictures,numbers (pj.ladd)
2. 04:08 AM - Re: Re: M3X pictures,numbers (pj.ladd)
3. 05:25 AM - Re: Re: M3X pictures,numbers (Jack B. Hart)
4. 06:42 AM - Re: Re: M3X pictures,numbers (russ kinne)
5. 07:16 AM - Re: Re: M3X pictures,numbers (Richard & Martha Neilsen)
6. 07:16 AM - Re: M3X pictures,numbers (lucien)
7. 07:52 AM - Re: Re: M3X pictures,numbers (pj.ladd)
8. 07:57 AM - Re: Re: M3X pictures,numbers (pj.ladd)
9. 08:16 AM - Re: Re: M3X pictures,numbers (pj.ladd)
10. 08:16 AM - Re: Re: M3X pictures,numbers (pj.ladd)
11. 08:33 AM - Re: M3X pictures,numbers (lucien)
12. 08:58 AM - Re: Re: M3X pictures,numbers (russ kinne)
13. 10:16 AM - Re: Re: M3X pictures,numbers (Dana Hague)
Message 1
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| Subject: | Re: M3X pictures,numbers |
climbing out of ground effect will have the opposite effect.. There will be
a dramatic increase in the drag, which may be seen by the pilot as a loss of
thrust. At any rate, the increase can be quite dramatic when an aircraft
that was flying just a second ago quits and settles back to the runway. .
Hi Lucien,
thanks for the reference to that article quoted above.
I think it validates just what |I said. If I may paraphrase "Flying in
ground effect means that you are airborne but not `really` up to flying
speed" That is not to say that the effect cannot or should not be used. In
the particular circumstance of a soft or rough field , but even if you have
done it zillions of times unless you NEED to use it ,it is a pointless
exercise.
It is much safer to have a few mph in hand above stalling speed BEFORE you
leave the ground.
Cheers
Pat
Message 2
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| Subject: | Re: M3X pictures,numbers |
. I fly
in ground effect, a couple feet off the ground, until I reach Vx or
Vy, your choice. >>
Hi Russ,
I said this one would run and run.
You obviously have had much more experience than I but unless you need to be
quickly clear of rough or soft ground I would rather build up the speed with
my wheels on the ground and then lift her off.
Cheers
Pat
Message 3
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| Subject: | Re: M3X pictures,numbers |
At 12:02 PM 5/14/09 +0100, you wrote:
>
>You obviously have had much more experience than I but unless you need to be
>quickly clear of rough or soft ground I would rather build up the speed with
>my wheels on the ground and then lift her off.
>
Pat,
With the FireFly, I always tease it off into ground effect, then advance the
throttle and accelerate it up to at least 50mphi before climbing out. There
are several reasons for this. Normally I fly off a runway that is open on
one side and a subdivision on the opposite side that includes tall trees. I
have found that the air closer to the ground is less disturbed and lower
velocity than air higher up when a cross wind is coming over or around the
subdivision. I like the idea of getting the FireFly completely under
control and up to speed just one or two feet off the ground before blasting
on up into the turbulence.
Taking off and landing in/on grass is the exception for me. I have been
suckered onto tall grass fields and grass runways that were covered with
water that could not be seen until you were touching down. These
conditions make for interesting take off because of the FireFly's small
wheels.
Jack B. Hart FF004
Winchester, IN
Message 4
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| Subject: | Re: M3X pictures,numbers |
Pat
You're right, and this needn't run on forever! I think we're saying
pretty much the same thing anyway.
On hard-surfaced runways I lift the tail about 50-55 & lift off about
70-75. (Vx is around 62)
On soft ground or grass I lift off as soon as I can, usually below
60. This immediately stops the drag of grass or soft ground & I can
accelerate faster, in ground effect, until I reach 70 or more; then
climb out.
Both hands on the controls all the time of course!
In a couple inches of soft snow you may have to make several runs up
& down the runway to mash the snow down & pack a couple of sort-of-
paved ruts for your wheels to run in, without a lot of drag.
Otherwise you wouldn't ever get fast enough for a takeoff.
Not suggesting anything to anybody, but it works for me.
Russ
On May 14, 2009, at 7:02 AM, pj.ladd wrote:
>
> . I fly
> in ground effect, a couple feet off the ground, until I reach Vx or
> Vy, your choice. >>
>
> Hi Russ,
> I said this one would run and run.
>
> You obviously have had much more experience than I but unless you
> need to be quickly clear of rough or soft ground I would rather
> build up the speed with my wheels on the ground and then lift her off.
>
> Cheers
>
> Pat
>
>
Message 5
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| Subject: | Re: M3X pictures,numbers |
Pat
Flying in ground effect is flying within one half the wings span of the
ground. Lift is increased, drag decreased, and stall speed is less. There is
a whole type of craft that never goes above ground effect called WIG.
Now to make this Kolb related. When we talk about flaps we need to specify
flaps verses flaperons. In Kolbs flaps produce mostly drag and some
increased lift. I'm told that flaps are considerable more effective in
producing drag than flaperons.
When flaps (all Kolb types) are retracted the angle of incidence of the wing
is reduced so if nothing else is done a Kolb will not fall out of the sky
even when near stall speed. Granted when flaps are reduced there is some
pitch up trim change but as pilot in command I'm not just along for the ride
so I adjust pitch for the conditions. Also in take off conditions my plane
will noticeably surge ahead when I reduce flaps from one notch to none so
any potential stall is quickly eliminated well ahead the impact of a pitch
trim change.
When flying a standard gear leg Kolb you can't get off the ground till you
are well above stall speed even with flaps. If you switch to the longer gear
legs Kolb recommends that you reduce the incidence of the wing. Also flying
a 912 (any) or a Redrive VW powered Kolb the acceleration is sufficient that
you have to work at keeping the airspeed low for a better climb rate. Under
powered Kolbs may react differently.
I do on occasion take off with a strong down wind from my one way strip. But
again I'm not just along for the ride and I will add considerable airspeed
to my climb out of ground effect.
Also Pat, I have never heard of any Kolb flap handle mounted between my
elbow and shoulder??? Is that some England required mod? My old MKIIIC flap
handle is mounted about top of my head high.
Rick Neilsen
Redrive VW powered MKIIIC
----- Original Message -----
From: "pj.ladd" <pj.ladd@btinternet.com>
Sent: Thursday, May 14, 2009 6:57 AM
Subject: Re: Kolb-List: Re: M3X pictures,numbers
>
> climbing out of ground effect will have the opposite effect.. There will
> be a dramatic increase in the drag, which may be seen by the pilot as a
> loss of thrust. At any rate, the increase can be quite dramatic when an
> aircraft that was flying just a second ago quits and settles back to the
> runway. .
>
> Hi Lucien,
> thanks for the reference to that article quoted above.
>
> I think it validates just what |I said. If I may paraphrase "Flying in
> ground effect means that you are airborne but not `really` up to flying
> speed" That is not to say that the effect cannot or should not be used.
> In the particular circumstance of a soft or rough field , but even if you
> have done it zillions of times unless you NEED to use it ,it is a
> pointless exercise.
> It is much safer to have a few mph in hand above stalling speed BEFORE you
> leave the ground.
>
> Cheers
>
> Pat
>
>
>
Message 6
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| Subject: | Re: M3X pictures,numbers |
pj.ladd(at)btinternet.com wrote:
> climbing out of ground effect will have the opposite effect.. There will be
> a dramatic increase in the drag, which may be seen by the pilot as a loss of
> thrust. At any rate, the increase can be quite dramatic when an aircraft
> that was flying just a second ago quits and settles back to the runway. .
>
> Hi Lucien,
> thanks for the reference to that article quoted above.
>
> I think it validates just what |I said. If I may paraphrase "Flying in
> ground effect means that you are airborne but not `really` up to flying
> speed" That is not to say that the effect cannot or should not be used. In
> the particular circumstance of a soft or rough field , but even if you have
> done it zillions of times unless you NEED to use it ,it is a pointless
> exercise.
> It is much safer to have a few mph in hand above stalling speed BEFORE you
> leave the ground.
>
> Cheers
>
> Pat
Er, no it kind of refutes what you said ;). That's the "effect" of ground effect
- remember, stall is determined by _AoA, not airspeed_. When flying in ground
effect, you already _are_ safely below stall AoA at a significantly lower airspeed
because of the effective increase in wingspan and aspect ratio. Thus,
you lift off at a lower ground speed, which is easier on the tires, airframe and
everything.
But, it's quite right you're not going fast enough to be able to fly out of ground
effect - that's why you stay in it until you get enough speed up to maintain
a safe AoA _out_ of GE.....
It's not a useless exercise, it's good practice and one that has been taught forever
as far as I know. For soft fields, of course, it's practically required
technique.
LS
--------
LS
Titan II SS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=243990#243990
Message 7
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| Subject: | Re: M3X pictures,numbers |
<< Thus, you lift off at a lower ground speed, which is easier on the tires,
airframe and everything.
But, it's quite right you're not going fast enough to be able to fly out of
ground effect - that's why you stay in it until you get enough speed up to
maintain a safe AoA _out_ of GE.....>>
Hi Lucien
All that is of course true but in the case of our machines what are we
tallking about...5 mph? How much wear and tear can that produce? What have
you saved .. just a few seconds of rolling time.
As your article states `if you are not up to speed when you try to fly out
of GE you will be back on th ground` I would rather be on the ground for
those extra few seconds and then rotate positively.
Good thread though
Pat
Message 8
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| Subject: | Re: M3X pictures,numbers |
Also Pat, I have never heard of any Kolb flap handle mounted between my
elbow and shoulder???>>
I wish I hadn`t . It is b******y awkward. You get used to it but you
certainly don`t want to be messing about with it close to the ground. It is
not just a mod. required over here. That was the way the kit came.
I think it must have escaped when the works were not looking.
Cheers
Pat,
Message 9
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| Subject: | Re: M3X pictures,numbers |
Otherwise you wouldn't ever get fast enough for a takeoff.(in Snow)
Russ,
A very experienced micro flier once told me that one year when there was
heavy snowfall and he couldn`t leave his farm to visit his girl friend he
tied the bumpers from an old car on to his microlights undercarriage. He
said it worked. He was a pretty hairy flyer anyway
Pat
Message 10
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| Subject: | Re: M3X pictures,numbers |
I always tease it off into ground effect, then advance the
throttle and accelerate it up to at least 50mphi before climbing out.>.
Hi Jack,
different techniques suit different people and different circumstances. The
grass on my strip is usually reasonably well cut and in any case there is a
fair amount of room.
I always use one notch of flap, always take off at full throttle and always
get the tail up as quickly as possible. Inever watch the ASI. I watch the
runway. The Kolb and the seat of your pants will tell you when she is ready
to fly.
Pat
Message 11
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| Subject: | Re: M3X pictures,numbers |
pj.ladd(at)btinternet.com wrote:
>
> Hi Lucien
> All that is of course true but in the case of our machines what are we
> tallking about...5 mph? How much wear and tear can that produce? What have
> you saved .. just a few seconds of rolling time.
Lot more than that. even in my FSII. If I kept the tail glued to the runway on
the roll, I'd lift off around the time the ASI started moving. The difference
in terms of wobbling when my wheels weren't balanced too well was significant,
not to mention if I wasn't dead on with the rudder.
In the titan, it's literally more than 20mph slower than Vx, with enough back elevator
I can get off the ground at somewhere between 40 and 45, even slower if
I use about 10 degs of flaps.
>
> As your article states `if you are not up to speed when you try to fly out
> of GE you will be back on th ground` I would rather be on the ground for
> those extra few seconds and then rotate positively.
>
> Good thread though
> Pat
Er, that's what flying lessons are for ;). It takes training and practice to learn
how to manage a soft-field technique so that you don't do this.
Nowadays, I use soft-field technique on practically every takeoff and the difference
in terms of liftoff speed is large.....
LS
--------
LS
Titan II SS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=244018#244018
Message 12
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| Subject: | Re: M3X pictures,numbers |
Egad, Pat!
I never had a girl friend cute enough to make me do that!
On May 14, 2009, at 11:00 AM, pj.ladd wrote:
>
> Otherwise you wouldn't ever get fast enough for a takeoff.(in Snow)
>
> Russ,
> A very experienced micro flier once told me that one year when
> there was heavy snowfall and he couldn`t leave his farm to visit
> his girl friend he tied the bumpers from an old car on to his
> microlights undercarriage. He said it worked. He was a pretty hairy
> flyer anyway
>
> Pat
>
>
Message 13
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| Subject: | Re: M3X pictures,numbers |
At 10:50 AM 5/14/2009, pj.ladd wrote:
>...I would rather be on the ground for those extra few seconds and then
>rotate positively.
The whole point of the takeoff run is to get the aircraft up to a safe and
appropriate airspeed for climbout. You do this by reducing drag as much as
possible. For a taildragger, this means raising the tail to reduce wing
drag; wheels have less drag than a wing that's producing lift... unless the
field is soft enough or has grass long enough that it would cause more drag
than the lift induced drag, in which case it would make more sense to
accelerate in ground effect.
In a strong steady crosswind, it may also make more sense to lift off
sooner so the wind isn't trying to weathervane the plane while still on the
ground.
-Dana
--
OK, I'm weird! But I'm saving up to be eccentric.
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