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Kyri

Needle 124 setup help

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Kyri

Hi everyone, this is my first post here!

Having flown powered gliders and F5B for a while, recently I flew on a couple of local slopes with a friend of mine who is a keen slopeflyer. I can see how it is very addictive, already. 

I bought a crashed needle some time ago and during last winter, and this summer, I have been fixing it up.  Fuz was in a few pieces, nose broken off and behind the wing snapped off, ailerons off, some crunching of the wings etc. Spars OK. 

During my first slope outing there was 30mph wind and I decided not to test it. On my second outing, with half that amount of wind (or less) I flew a mini ellipse a few times before  the needle. It flew, but it is nowhere near setup properly yet, and it kept dropping a wing and flicking and I have been trying to figure out what to do next. I have some ideas, but want to discuss it with people who know more about this plane.  It flew straight with no ele trim so I think the fuz rebuild was OK.

My first change will be to lower the elevator movement (by a lot...). I am also considering slight camber if in lower wind.  More wind, and some ballast may also help but I think it should have flown in the conditions and my poor setup may have been the cause. 

What do you think? I can elaborate more on the setup if needed. I just don't want to break it, as I spent a while fixing it and want to enjoy flying it, hence me getting some advice on my journey to get to know this plane and set it up properly. 

Thanks!

Kyri

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simon_t

This is from Thuro, the Needle designer, if you don’t already have them:

Settings:
CG: 95 - 98 mm
Ailerons: up 17 mm, down 11-12 mm
Flaps: down about 55 - 65 ° for Butterfly (not too much because otherwise the model balloons), ailerons up almost up. Add mix allow 100% Differential at full Butterfly.
Elevator down compensation at full Butterfly approximately 4.5 - 5 mm.
Elevator: max. 6-7mm up and down.
Rudder: 10-11mm
Thermal setting: Wing, all trailing edge in line 2-3mm droop. A Tx slider can also be used to adjust the amount of droop.
SnapFlap: 5-8mm to 8 mm droop all trailing edge in line. Performance can be improved by programming an additional mixer...
[The next bit describes a mixer which changes the differential as more or less snap flap is applied – I need more work on understanding this, but I think it is due to the effect that when the aileron is drooped with snap, and you are rolling out of a turn, the up-going aileron will actually end up in a lower drag position as it goes through neutral, which screws the differential - Simon]
A curve mixer program so that is not affected when disconnected from the elevator and
acting in a row SnapFlap the aileron differential. Namely elevator operated simultaneously
with aileron (happened every flight curve) so that the differentiation of the aileron SnapFlap
affected because the downward worn out, further differential aileron deflects downward
because SnapFlap dzu acts. When opposing aileron the situation is reversed, where the
ailerons are smaller upwards. Both factors have a disastrous effect on the differentiation
and it is even negative.
Well, then adjust the mixer so that the full amount of differentiation at the appropriate value
(eg 30% at 40% diff.) Reduced. The same goes for the inner flaps.
I can not describe to you exactly how this is done at your facility but at the Futaba systems
are easy to accomplish with the fine trim.
Tip for flying:
To determine the exact center of gravity is there a simple way: Although that with a needle
is not necessarily noticeable, I recommend the following method:
First, fly the model in level flight. Now bring the model to a slightly downward sloping trajectory. The model should hold this trajectory, or very slowly raise it's nose. If the model's nose rises up pretty quickly then the CG is too far forward. If the model drops it's nose, then CG is too far rearwards.

 

Simon

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Kyri

Thanks Simon.

My elevator movement was almost double, and even though it looked like too much I could not reduce it due to the mechanical arrangement (at lowest rates on the tx). This is because when I got the model the fuz was snapped and the pushrods too. I decided to put servos in the tail with short linkages. I will move the pushrod to the hole nearest to the spline on the servos which should get me 6-7mm max.  (he must have mentioned "max" for a reason!)

As for cg, I was more forward than that, around 90mm. 

Looking at it now , the combination of those two things is not good, and might explain what was happening. 

As for the rest of the information you gave, I will read and digest it.

Cheers

Kyri

 

 

 

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Lloyd_d

You do not need much elevator travel as the speed range of the model is very high and it is quite elevator sensitive. I was initially at +/- 7.5mm elevator but found it very twitchy at speed so had to drop it to something like 6.5mm and a lot more expo.

Try to have it pitch nose down when using crow braking otherwise it will balloon up when taking them off and you could stall and drop a wing

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simon_t

Make sure you have some differential set up on the Ailerons as well.  I think I had around 20mm up aileron and 14mm down.  Without differential you will get adverse yaw and tip stalls.  

The Needle has very small tail area, which means it can be very sensitive to incorrect settings (e.g. poor differential leads to excessive yaw, over sensitive elevator).  But once set up it is a very fast and fine flying model - Mine took me to second place overall in the FAI F3F World Cup league a few years ago, with around 300 pilots competing, up against lots of Freestylers and other fine models.

It is also designed to have a wing area allowing it to be ballasted to just under 5Kg whilst remaining contest legal - most other models can only use less ballast.  But it means for sport flying the model is fast and has a huge ‘carry’ allowing huge loops and the like to be flown.

Have fun!

Simon

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Kyri

Simon and Lloyd,

This has been very helpful to me, thanks. I checked everything again:

1. No differential on the ailerons. I did not realise how important it is, and usually put it on my other planes. 

2. 12mm elevator travel on quite fast servos.

3. CG 90mm (the mark on the wing is at 92, it was balanced slightly in front so may even have been <90 from leading edge.

4. No snap flap 

5. No rudder

I can sort 1-3 relatively easily, but for snap flap I am limited on my current transmitter. A friend of mine has let me try an old  tx  of his that is more functional and I also have a taranis if I can tear myself away from my old futaba that is. One of the issues is that I have is that I still use throttle stick for power on my f5b planes and programmed full left rudder as proportional crow. This may be the time to start using the throttle stick for crow so I can get use of the other mixers back and use  snapflap etc. However I don't think this is what caused my issues with flicking (although, with some camber whilst turning maybe the stall would have been delayed?)

Great to hear that you found half the elevator movement that I was using enough, no wonder I had to fly with the lightest touch I have ever flown with just to keep it in the air!

Also I had a look at the ballast. There is quite a bit of it.  It will be great to get this thing loaded up and generating some lift and speed, rather than pottering around the sky almost stalling due to my poor setup. It is nice to hear that this is a such a capable plane (although I am sure the piloting had something to do with the 2nd place out of 300 Simon). I knew when I started repairing it that this is a well made plane with thought gone into the design and construction. 

Will keep you informed of my progress.

Thanks again,

 

Kyri

 

 

 

 

 

 

 

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simon_t

The CG at 90 will not be a problem,  I wouldn’t play with that until the rest is sorted - it is forward which is better than backward, and it has quite a good CG range anyway.  For sport flying snap flap is not so important, but rudder is - these models need to be flown with rudder at slower speeds - I always flew with an aileron to rudder mix, which was about 5% in my speed setting, but about 20% in climbout/thermal setting.  If you can set up a camber flap on a switch to droop the whole trailing edge about 2-3mm at root it will help your climbout in lighter conditions.  (keep ailerons aligned with flaps - don’t be tempted to use less droop on the ailerons to give it a bit of ‘washout’ - it doesn’t need it and it is less efficient).

Simon

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wookman
22 minutes ago, simon_t said:

snap flap is not so important, but rudder is - these models need to be flown with rudder at slower speeds

Yawing and Braking, it's what your left thumb is for!

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Witch_1
On 09/10/2018 at 20:53, Kyri said:

Also I had a look at the ballast. There is quite a bit of it.  It will be great to get this thing loaded up

 

On 09/10/2018 at 22:41, simon_t said:

The CG at 90 will not be a problem,

Dont forget at CG in low 90's the wing ballast tubes, and probably fuse one, will be significantly behind the CG.  You will need noseweight adjustment with ballast if you dont want it to move backwards too much.

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Kyri

Thanks, I will bear this in mind.  There are a couple of lead nose weights, one bigger than the other so this should be possible. Also since I put the servos in the tail I need more weight in the front than usual.

Unfortunately one of the servos stopped working when I was playing around setting the differential. No binding, and no hot servos, but on taking it apart there is a slight blackened area around the inside of the case at the bottom of the motor.  It is a discontinued DS6125 so it will need to be replaced it before I can fly again. At least it didn't happen in the air. 

 

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Witch_1

If you want a single replacement 6125 may be worth putting a wanted ad in the For Sale section, as some may have taken them out to convert to HV.  Otherwise its a pair of new 6130s.

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Kyri

Great idea, had a look but I need 10 posts before I can put a wanted ad so I'd better get posting 🙂

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Witch_1

You've got a Needle.... if you think you might like to try one of the pretty relaxed winter F3F competitions, then perhaps have a look on that section and introduce yourself....  Lots of advice available on setups too if you go to an F3F.

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Munch197

There's a 6125H on eBay should you need a replacement. Not sure on your tab setup though

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simon_t
8 hours ago, Kyri said:

Great idea, had a look but I need 10 posts before I can put a wanted ad so I'd better get posting 🙂

Lots of people seem to post ads without reaching that, so give it a try.  

ps, I have plenty of 6125s here if you need one

Simon

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Kyri
19 hours ago, Witch_1 said:

You've got a Needle.... if you think you might like to try one of the pretty relaxed winter F3F competitions, then perhaps have a look on that section and introduce yourself....  Lots of advice available on setups too if you go to an F3F.

I may just do that, although a friend who I fly with is a keen slope soarer so I have the chance to get to some local slopes and get this thing dialed in. At some point I would like to see what the comps are like, having been involved in a different discipline, I know how much fun it can be and how it can make you a better pilot. 

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Kyri
15 hours ago, Munch197 said:

There's a 6125H on eBay should you need a replacement. Not sure on your tab setup though

Thanks for the suggestion!

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Kyri

Just testing how to add pictures to threads, here is one of the fuz during the rebuild:

 

 

2needle broken.JPG

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Nick Jackson

You're nearly there anyway but 10 post minimum doesn't apply if you join BARCS. 

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Kyri

Thank you Nick, I just checked it out and joined. Now that I am getting into slope soaring it makes sense. Everyone has been very helpful and there is lots of information available by searching, I am finding. 

 

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