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Old Jan 20, 2004, 03:00 AM
Bob
Guest
n/a Posts
trimming a flying wing.


I have recently got a small EPP wing, and having a few difficulties.

It is similar to the zagi style of wing, but smaller.

It is powered by a speed 280, with a 5x4.2 and is approx 32"

The flying weight it comes out at is 220g, which is in the correct range of
200-250g.

I have set it up so the COG is exactly where recommended, but in the flying,
to maintain level flight at full throttle I need to have a lot of up (3/4 of
available). Whenever I try and give airleron input, as it starts turning,
the higher wing stalls, then drops.

Basically, I can only fly in a straight line.

Any wing guru's experienced something like this, and is it a balance
problem?


Old Jan 20, 2004, 03:00 AM
Don Hatten
Guest
n/a Posts
Re: trimming a flying wing.

Do you have some reflex in the elevons? You should have some, how much
depends on what the kit maker recommends as a starting point. Also, you
shouldn't need too much control throw, maybe 1/2" max with more up than
down..

"Bob" <bNOoONb@not.pilbara.net.au> wrote in message
news:buhrbp$akn$1@mws-stat-syd.cdn.telstra.com.au...
>
> I have recently got a small EPP wing, and having a few difficulties.
>
> It is similar to the zagi style of wing, but smaller.
>
> It is powered by a speed 280, with a 5x4.2 and is approx 32"
>
> The flying weight it comes out at is 220g, which is in the correct range

of
> 200-250g.
>
> I have set it up so the COG is exactly where recommended, but in the

flying,
> to maintain level flight at full throttle I need to have a lot of up (3/4

of
> available). Whenever I try and give airleron input, as it starts turning,
> the higher wing stalls, then drops.
>
> Basically, I can only fly in a straight line.
>
> Any wing guru's experienced something like this, and is it a balance
> problem?
>
>



Old Jan 20, 2004, 03:00 AM
W4JLE
Guest
n/a Posts
Re: trimming a flying wing.

How do you have the mixing set up on the transmitter?

"Bob" <bNOoONb@not.pilbara.net.au> wrote in message
news:buhrbp$akn$1@mws-stat-syd.cdn.telstra.com.au...
>
> I have recently got a small EPP wing, and having a few difficulties.
>
> It is similar to the zagi style of wing, but smaller.
>
> It is powered by a speed 280, with a 5x4.2 and is approx 32"
>
> The flying weight it comes out at is 220g, which is in the correct range

of
> 200-250g.
>
> I have set it up so the COG is exactly where recommended, but in the

flying,
> to maintain level flight at full throttle I need to have a lot of up (3/4

of
> available). Whenever I try and give airleron input, as it starts turning,
> the higher wing stalls, then drops.
>
> Basically, I can only fly in a straight line.
>
> Any wing guru's experienced something like this, and is it a balance
> problem?
>
>



Old Jan 20, 2004, 03:00 AM
Dr1Driver
Guest
n/a Posts
Re: trimming a flying wing.

>Any wing guru's experienced something like this, and is it a balance
>problem?


Flying wings normally need the ailerons kicked up in a "reflex" attitude. No
idea how much to tell you on that plane, sorry. Experiment...
Dr.1 Driver
"There's a Hun in the sun!"
Old Jan 20, 2004, 03:00 AM
Bob
Guest
n/a Posts
Re: trimming a flying wing.


Ok,

I have approx 1" up and 1" down of control throws, I am flying with approx
3/4 up ALL the time to maintain level flight.

I am thinking that there is some sort of balance problem. I was hoping
someone may have experienced a similar problem, and help with determining if
it is a balance either being too far f/w or back to how it actually
performs.

I guess that I will take some small weights with me and go and try and find
out what the problems are!

Bob in Aus


"Don Hatten" <hattend@starband.net> wrote in message
news:vl%Ob.19307$UY.1361337527@twister2.starband.n et...
> Do you have some reflex in the elevons? You should have some, how much
> depends on what the kit maker recommends as a starting point. Also, you
> shouldn't need too much control throw, maybe 1/2" max with more up than
> down..
>
> "Bob" <bNOoONb@not.pilbara.net.au> wrote in message
> news:buhrbp$akn$1@mws-stat-syd.cdn.telstra.com.au...
> >
> > I have recently got a small EPP wing, and having a few difficulties.
> >
> > It is similar to the zagi style of wing, but smaller.
> >
> > It is powered by a speed 280, with a 5x4.2 and is approx 32"
> >
> > The flying weight it comes out at is 220g, which is in the correct range

> of
> > 200-250g.
> >
> > I have set it up so the COG is exactly where recommended, but in the

> flying,
> > to maintain level flight at full throttle I need to have a lot of up

(3/4
> of
> > available). Whenever I try and give airleron input, as it starts

turning,
> > the higher wing stalls, then drops.
> >
> > Basically, I can only fly in a straight line.
> >
> > Any wing guru's experienced something like this, and is it a balance
> > problem?
> >
> >

>
>



Old Jan 20, 2004, 03:00 AM
Bob
Guest
n/a Posts
Re: trimming a flying wing.


standard Elevon mixing, (JR652 Tx)

"W4JLE" <w4jle(remove to reply)@pbtcomm.net> wrote in message
news:bui567$783d$1@news3.infoave.net...
> How do you have the mixing set up on the transmitter?
>



Old Jan 20, 2004, 03:00 AM
Maarten
Guest
n/a Posts
Re: trimming a flying wing.

Normally it need a max of 1/32" up to maintain altitude.
So you hav to move your COG backwards. If it is 3/4" up then put it back
about 1/2 ".
Then in smaller steps. Do not try to turn yet in this trimming round. Just
straight lines trying to keep altitude.
Next to this you need speed to maintain altitude.Go full power and when
launching it make sure that it has enough speed (do not thow it upwards but
in a straight horizontal line.)

Succes,
Maarten
"Bob" <bNOoONb@not.pilbara.net.au> wrote in message
news:buib5i$m7r$1@mws-stat-syd.cdn.telstra.com.au...
>
> Ok,
>
> I have approx 1" up and 1" down of control throws, I am flying with approx
> 3/4 up ALL the time to maintain level flight.
>
> I am thinking that there is some sort of balance problem. I was hoping
> someone may have experienced a similar problem, and help with determining

if
> it is a balance either being too far f/w or back to how it actually
> performs.
>
> I guess that I will take some small weights with me and go and try and

find
> out what the problems are!
>
> Bob in Aus
>
>
> "Don Hatten" <hattend@starband.net> wrote in message
> news:vl%Ob.19307$UY.1361337527@twister2.starband.n et...
> > Do you have some reflex in the elevons? You should have some, how much
> > depends on what the kit maker recommends as a starting point. Also, you
> > shouldn't need too much control throw, maybe 1/2" max with more up than
> > down..
> >
> > "Bob" <bNOoONb@not.pilbara.net.au> wrote in message
> > news:buhrbp$akn$1@mws-stat-syd.cdn.telstra.com.au...
> > >
> > > I have recently got a small EPP wing, and having a few difficulties.
> > >
> > > It is similar to the zagi style of wing, but smaller.
> > >
> > > It is powered by a speed 280, with a 5x4.2 and is approx 32"
> > >
> > > The flying weight it comes out at is 220g, which is in the correct

range
> > of
> > > 200-250g.
> > >
> > > I have set it up so the COG is exactly where recommended, but in the

> > flying,
> > > to maintain level flight at full throttle I need to have a lot of up

> (3/4
> > of
> > > available). Whenever I try and give airleron input, as it starts

> turning,
> > > the higher wing stalls, then drops.
> > >
> > > Basically, I can only fly in a straight line.
> > >
> > > Any wing guru's experienced something like this, and is it a balance
> > > problem?
> > >
> > >

> >
> >

>
>



Old Jan 20, 2004, 03:00 AM
Six_O'Clock_High
Guest
n/a Posts
Re: trimming a flying wing.

Bob,
The "reflex" is normally seen as the elevons being viewed as UP when in the
center of their travel.

Here is a way you should be able to begin to fix your problem. With the Tx
and Rx ON (and motor disconnected!), move the elevator stick to the location
you need to hold to get it straight and level with the plane on a table.
Then while holding that elevator, turn off the RX. That should leave the
elevons in the UP mode you need. Measure the distance from the table to the
top edge of each elevon with the wing secured to the table by heavy (5
pound) weights. Then turn the RX and TX on for a moment making sure the
elevator trim is in the center. Unscrew the servo wheels and move them
until the top edge of the elevon is at the same distance above the table you
measured earlier. Reinstall the screws and turn on the RX and TX to check
that you still have equal travel in both directions on both surfaces because
you may need to make an engineering change or two to the entire control
system - that is no fun, but it should not be a stopper.Go test fly it and
see if it is better or worse.

"Bob" <bNOoONb@not.pilbara.net.au> wrote in message
news:buib5i$m7r$1@mws-stat-syd.cdn.telstra.com.au...
>
> Ok,
>
> I have approx 1" up and 1" down of control throws, I am flying with approx
> 3/4 up ALL the time to maintain level flight.
>
> I am thinking that there is some sort of balance problem. I was hoping
> someone may have experienced a similar problem, and help with determining

if
> it is a balance either being too far f/w or back to how it actually
> performs.
>
> I guess that I will take some small weights with me and go and try and

find
> out what the problems are!
>
> Bob in Aus
>
>
> "Don Hatten" <hattend@starband.net> wrote in message
> news:vl%Ob.19307$UY.1361337527@twister2.starband.n et...
> > Do you have some reflex in the elevons? You should have some, how much
> > depends on what the kit maker recommends as a starting point. Also, you
> > shouldn't need too much control throw, maybe 1/2" max with more up than
> > down..
> >
> > "Bob" <bNOoONb@not.pilbara.net.au> wrote in message
> > news:buhrbp$akn$1@mws-stat-syd.cdn.telstra.com.au...
> > >
> > > I have recently got a small EPP wing, and having a few difficulties.
> > >
> > > It is similar to the zagi style of wing, but smaller.
> > >
> > > It is powered by a speed 280, with a 5x4.2 and is approx 32"
> > >
> > > The flying weight it comes out at is 220g, which is in the correct

range
> > of
> > > 200-250g.
> > >
> > > I have set it up so the COG is exactly where recommended, but in the

> > flying,
> > > to maintain level flight at full throttle I need to have a lot of up

> (3/4
> > of
> > > available). Whenever I try and give airleron input, as it starts

> turning,
> > > the higher wing stalls, then drops.
> > >
> > > Basically, I can only fly in a straight line.
> > >
> > > Any wing guru's experienced something like this, and is it a balance
> > > problem?
> > >
> > >

> >
> >

>
>



Old Jan 20, 2004, 03:00 AM
Bob
Guest
n/a Posts
Re: trimming a flying wing.

I have just managed to find someone else who has a couple of these wings and
recommended a similar thing.

I will take a few small weights with me and do some experiments and see how
it flies....

Thanks for the advice, I will let you know how it goes...

Bob in Aus

"Maarten" <mmg_brouwers@hotmail.com> wrote in message
news:buicq2$118$1@news4.tilbu1.nb.home.nl...
> Normally it need a max of 1/32" up to maintain altitude.
> So you hav to move your COG backwards. If it is 3/4" up then put it back
> about 1/2 ".
> Then in smaller steps. Do not try to turn yet in this trimming round. Just
> straight lines trying to keep altitude.
> Next to this you need speed to maintain altitude.Go full power and when
> launching it make sure that it has enough speed (do not thow it upwards

but
> in a straight horizontal line.)
>
> Succes,
> Maarten
> "Bob" <bNOoONb@not.pilbara.net.au> wrote in message
> news:buib5i$m7r$1@mws-stat-syd.cdn.telstra.com.au...
> >
> > Ok,
> >
> > I have approx 1" up and 1" down of control throws, I am flying with

approx
> > 3/4 up ALL the time to maintain level flight.
> >
> > I am thinking that there is some sort of balance problem. I was hoping
> > someone may have experienced a similar problem, and help with

determining
> if
> > it is a balance either being too far f/w or back to how it actually
> > performs.
> >
> > I guess that I will take some small weights with me and go and try and

> find
> > out what the problems are!
> >
> > Bob in Aus
> >
> >
> > "Don Hatten" <hattend@starband.net> wrote in message
> > news:vl%Ob.19307$UY.1361337527@twister2.starband.n et...
> > > Do you have some reflex in the elevons? You should have some, how

much
> > > depends on what the kit maker recommends as a starting point. Also,

you
> > > shouldn't need too much control throw, maybe 1/2" max with more up

than
> > > down..
> > >
> > > "Bob" <bNOoONb@not.pilbara.net.au> wrote in message
> > > news:buhrbp$akn$1@mws-stat-syd.cdn.telstra.com.au...
> > > >
> > > > I have recently got a small EPP wing, and having a few difficulties.
> > > >
> > > > It is similar to the zagi style of wing, but smaller.
> > > >
> > > > It is powered by a speed 280, with a 5x4.2 and is approx 32"
> > > >
> > > > The flying weight it comes out at is 220g, which is in the correct

> range
> > > of
> > > > 200-250g.
> > > >
> > > > I have set it up so the COG is exactly where recommended, but in the
> > > flying,
> > > > to maintain level flight at full throttle I need to have a lot of up

> > (3/4
> > > of
> > > > available). Whenever I try and give airleron input, as it starts

> > turning,
> > > > the higher wing stalls, then drops.
> > > >
> > > > Basically, I can only fly in a straight line.
> > > >
> > > > Any wing guru's experienced something like this, and is it a balance
> > > > problem?
> > > >
> > > >
> > >
> > >

> >
> >

>
>



Old Jan 20, 2004, 06:01 PM
David
Guest
n/a Posts
Re: trimming a flying wing.

I am only a beginner, but wonder if the motor has a lot of downthrust? And so
you have to use up elevator to keep it level???


David

Bob wrote:

> I have recently got a small EPP wing, and having a few difficulties.
>
> It is similar to the zagi style of wing, but smaller.
>
> It is powered by a speed 280, with a 5x4.2 and is approx 32"
>
> The flying weight it comes out at is 220g, which is in the correct range of
> 200-250g.
>
> I have set it up so the COG is exactly where recommended, but in the flying,
> to maintain level flight at full throttle I need to have a lot of up (3/4 of
> available). Whenever I try and give airleron input, as it starts turning,
> the higher wing stalls, then drops.
>
> Basically, I can only fly in a straight line.
>
> Any wing guru's experienced something like this, and is it a balance
> problem?


Old Jan 21, 2004, 03:00 AM
N9M
Guest
n/a Posts
Re: trimming a flying wing.

Bob,

Your CG should be at 15% - 19% of MAC. I fly my wings at 17% of MAC.

To calculate where 17% MAC is on your wing, go here:

http://www.palosrc.com/instructors/cg.htm

Where it says, "Enter %MAC Balance Point:" type in "17". This
calculator will tell you how far back from the tip of the leading edge
at the root your CG should be.

Feel free to email me direct to ask questions.

Jeff
Old Jan 21, 2004, 06:03 PM
A.T.
Guest
n/a Posts
Re: trimming a flying wing.

Most "wings" will set up nicely if the aiklerons follow the bottom airfoil
rather so as the wing takes on a "S" shape when viewed along the top of the
wing. i.e. 1 to 2% reflex.
For in depth info on thrust lines etc refer to =
http://homepages.ihug.co.nz/~atong/
and scroll down to =

"Flying Wings (inc Delta), Flapping Wings or Ornithopter. [see also Gliders
below.]"

Flying wings

Advanced Propulsion Home Page - JLN Labs
Airfoil Design for Tailless Airplanes 1
Andy MacDonalds Flying Wing page.
Airfoils for Flying Wings and Tailless Airplanes ***
Correx Deltas - good plans & video.
Flying Wings - Trimming
Flying Wing Models - Basic design
Foam Wing Construction
Mugi Correx Combat Flying Wing
Theoretical Flying wings
TWITT- The Wing is the Thing
Flying Wings : An Anthology
Birdworks - inc the RC Gull

Flapping Wings - Ornithopter

Bionics and Evolutiontechnique
CyBird (- with movies etc)
Flapping Flight Links
Flapping Flight - Ornithopters
Multiwinglets_Rueckstromtaschen
Ornithopters
ParkHawk
Robofalcon - Intercept technology
Truefly - Flying by flapping wings
The Flutterby
1900 Clark BiWing Ornithopter

Advanced Propulsion - JLN Labs

See aklso =

"Foam Wings, Warbirds, Foam Cutting Bows, Coroplast, PVC & SPAD. [see also
Gliders below.]"

regards
Alan T.

Alan's Hobby, Model & RC Links
http://homepages.ihug.co.nz/~atong/
.................................................. ............





"Bob" <bNOoONb@not.pilbara.net.au> wrote in message
news:buhrbp$akn$1@mws-stat-syd.cdn.telstra.com.au...
>
> I have recently got a small EPP wing, and having a few difficulties.
>
> It is similar to the zagi style of wing, but smaller.
>
> It is powered by a speed 280, with a 5x4.2 and is approx 32"
>
> The flying weight it comes out at is 220g, which is in the correct range

of
> 200-250g.
>
> I have set it up so the COG is exactly where recommended, but in the

flying,
> to maintain level flight at full throttle I need to have a lot of up (3/4

of
> available). Whenever I try and give airleron input, as it starts turning,
> the higher wing stalls, then drops.
>
> Basically, I can only fly in a straight line.
>
> Any wing guru's experienced something like this, and is it a balance
> problem?
>
>



Old Jan 21, 2004, 06:03 PM
N9M
Guest
n/a Posts
Re: trimming a flying wing.

> I am only a beginner, but wonder if the motor has a lot of downthrust? And so
> you have to use up elevator to keep it level???


I have found that at least on the flying wings I design, build and fly
that in a pusher prop configuration, about 4 degrees of downthrust
works great for me.

Flying wings sold on the market today require around 5 to 10 degrees
of reflex in the elevons to fly properly. That is if the CG is around
17% MAC.

Jeff
Old Jan 22, 2004, 06:01 PM
Bob in Aus
Guest
n/a Posts
Re: trimming a flying wing.


"N9M" <northropn9m@yahoo.com> wrote in message
news:dc67c867.0401201632.696e34c6@posting.google.c om...
> Bob,
>
> Your CG should be at 15% - 19% of MAC. I fly my wings at 17% of MAC.
>
> To calculate where 17% MAC is on your wing, go here:
>
> http://www.palosrc.com/instructors/cg.htm
>
> Where it says, "Enter %MAC Balance Point:" type in "17". This
> calculator will tell you how far back from the tip of the leading edge
> at the root your CG should be.
>
> Feel free to email me direct to ask questions.
>
> Jeff


I ran the numbers thru the calculator on the web page and they came up
surprisingly at 135mm from the Le at chord.

The instructions come at 155mm, and from what others are saying, I am NOSE
heavy.

I am thinking something is not right somewhere..... I have added some
weight to the motor, and moved the COG back approx 10-15 mm but yet, have
not had a chance to test fly and see if this is going in the right
direction.

Below URL is the actual model, and the image showing instructions on the
page is almost readable.

http://www.modelflight.com.au/rc_mod...le_280_epp.htm

I even asked people at the shop about this, and they are saying MOVE COG
BACK!. I just wanna get it to fly! Once I get it flying, It means 3 minutes
to the park to have a fly rather than 30 minutes to the flying field, or 2
hours to my 10Acre property to fly!

I will put together a summary when I get this thing sorted out and actually
flying!

Bob in Aus.





Old Jan 25, 2004, 03:00 AM
Bob in Aus
Guest
n/a Posts
Re: trimming a flying wing.


Jeff,

Thanks,

I have actually discussed this with the LHS where I purchased it, and the
recommendation was to MOVE IT BACK!

We discussed a lot of things, such as power etc, and when I said I was
getting over 4 oz of static thrust, he seemed surprised, as his is about 3
oz with the standard motor. (it pays to break in an electric motor!).

I will be test flying it again tomorrow afternoon and see what happens.

If all else fails, I will be talking to another person at the LHS who has
flown several of these wings and a lot of others as well.

"N9M" <northropn9m@yahoo.com> wrote in message
news:dc67c867.0401230652.7082da7f@posting.google.c om...
> Bob,
>
> I check the website with the instructions for your wing. Keep the CG
> as the instructions say...155 mm.
>
> If the wing is stalling in the turns, if it requires significant
> elevon deflection just to fly level and the CG is set according to the
> instructions, it sounds like it is flying very slow. My wings require
> almost 3/4 of full deflection just before stall speed.
>
> I wonder if your battery is delievering enough power to the motor. I
> wonder if the wing is so slow that it is flying just above stall
> speed.
>
> Jeff
>
>
> "Bob in Aus" <bREMOVEoMEb@norcom.net.au.remove.me> wrote in message

news:<400fddbf$0$4259$c30e37c6@lon-reader.news.telstra.net>...
> > "N9M" <northropn9m@yahoo.com> wrote in message
> > news:dc67c867.0401201632.696e34c6@posting.google.c om...
> > > Bob,
> > >
> > > Your CG should be at 15% - 19% of MAC. I fly my wings at 17% of MAC.
> > >
> > > To calculate where 17% MAC is on your wing, go here:
> > >
> > > http://www.palosrc.com/instructors/cg.htm
> > >
> > > Where it says, "Enter %MAC Balance Point:" type in "17". This
> > > calculator will tell you how far back from the tip of the leading edge
> > > at the root your CG should be.
> > >
> > > Feel free to email me direct to ask questions.
> > >
> > > Jeff

> >
> > I ran the numbers thru the calculator on the web page and they came up
> > surprisingly at 135mm from the Le at chord.
> >
> > The instructions come at 155mm, and from what others are saying, I am

NOSE
> > heavy.
> >
> > I am thinking something is not right somewhere..... I have added some
> > weight to the motor, and moved the COG back approx 10-15 mm but yet,

have
> > not had a chance to test fly and see if this is going in the right
> > direction.
> >
> > Below URL is the actual model, and the image showing instructions on the
> > page is almost readable.
> >
> >

http://www.modelflight.com.au/rc_mod...le_280_epp.htm
> >
> > I even asked people at the shop about this, and they are saying MOVE COG
> > BACK!. I just wanna get it to fly! Once I get it flying, It means 3

minutes
> > to the park to have a fly rather than 30 minutes to the flying field, or

2
> > hours to my 10Acre property to fly!
> >
> > I will put together a summary when I get this thing sorted out and

actually
> > flying!
> >
> > Bob in Aus.



 


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