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Kyri

Needle 124 setup help

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Kyri

I am back in business!!  Thanks very much to Simon for helping me take new ownership of some used 6125 minis so I now have the wing functional again. 

I can't wait to get flying again with  aileron differential, reduced elevator movement and possibly rudder mixing (not sure on the last bit, or if I will do that quite yet, for a few reasons...)

Hopefully 20mph winds on a local slope, maybe 1/2-1kg ballast in the joiner and it will fly much better. 

In the meantime I opened the non working servo to see if I could see what happened. It is possible that some sort of short took place, which might be from carbon dust making the case conductive. I am not sure, but it would be nice to know the cause.

You have all been very helpful, I will update in due course.

cheers

Kyri 

 

 

 

 

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Kyri

I flew the needle and it was great fun, no tip stalls or flicks with the reduced throws, and diff on ailerons. It was much easier in higher wind,  and with the ~20mph wind I put about 500g in the wing (two of the brass bars, and maybe 400 in the nose too). I could have put much more in, too. 

I had a great couple of flights, I put a gopro on my cap but the footage is poor, a little too small. I may see if I can get some video out of it.

There were a few events of the afternoon, such as discovering that a flap stick when I did a crow test up high on the first flight. As soon as I noticed it wasn't retracting properly I landed, to avoid draining the battery and losing the plane. The landing was uneventful, and I managed to land close to me so that as soon as the plane was down I could disconnect the battery. I kept the flaps down in the meantime and was able to land in a small bush to avoid the flaps being pulled back on landing (since I could not retract one of them)

At first I thought the flap/s had friction where the flap meets the fuz, as this is where it was snapped and could be oversized. I made a spacer out of layers of tape so that the wing cannot butt up as closely to the fuz. Further investigation also showed it was a small area where the top skin was snagging the wiper, so I taped the flap wiper in that area for the second flight. I will sort that out properly and maybe tape the whole lot later. 

The other "event" was that one of the flap servos moved position. This was after the second landing without retracting the flaps quickly enough. It is the second time it has happened, too, the first being at home when setting up. I had to move the horn on the flap to sort it, after checking it was not a radio problem. The only explanation I can think of is that the plastic horn has moved on the metal spline of the servo when stalling the flap. When trying to move the flap I cant recreate this, and don't want to force it just to prove a point! Maybe I will just change the plastic horn to a new one. Strangely, the flap ends up in a down position (about 20mm lower) which seems odd, and doesn't correlate with my theory in terms of the direction. Maybe I should just change that servo out.

In the meantime here is a pic of the landing. I really like this slope despite the climb up. and want to go again.

regards

Kyri

 

 

 

needle landing.JPG

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Kyri

I am ready for the next outing, with taped flap wipers, same cg and ballast plus an extra 500g ballast.

I'm  planning to add two of the lead pieces into the back of the joiner, which brings the cg ever so slightly forward. Taking  30-40g out of the nose brings the cg to the same point it was without the joiner lead (just under 92mm). That will be around 1kg of ballast.

Having read some previous threads, I see a massive range of cg's from 89 to over 100mm.  Is this range due to different wing loadings or just because the plane is well able to cope with a variety of cg's?

With my elevator movement at +/-6mm and 91-92mm cog, and 600g ballast(two long brass just behind joiner)  this is how it flew. Footage from my friends on board camera, you can hopefully get an impression of its flight characteristics. I have some footage from my cap cam but haven't uploaded it as the plane was too small really.

 

 

 

 

 

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Kyri

Regarding rx battery, I have been using eneloop ~2000 AA's x4, and although I never used them fresh off the charger I am wondering if this could have caused my servo problem. (too much voltage)

I am considering some other options like use the cc 10A bec on 5V, but what to power it with. I am thinking about 2s lipo but also wonder if old nicd sub c cells would be OK since they don't drop their voltage in the cold like nimh. This is as I think about winter flying. I would normally on my other (non mks) planes fly 4 nimh fresh off the charger, but after getting a mks failure and reading about the voltage sensitivity of these servos I am considering what to do. 

I appreciate that this has already been discussed to death and that lots have moved to hv servos but I just want to reduce the risk of losing what is a very nice plane!

 

 

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Phil.Taylor

You will never get too many volts from 4x eneloops! - even fresh off the charger

5x cells may cause trouble for some servos...

Phil.

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Kyri

That is reassuring to know, Phil, thanks. My other concern is them losing voltage or capacity during a session on a cold hill. I suppose I could keep a spare charged one in my pocket and change the one in the plane out if I am there for long enough. I could take a charger but its amazing how the weight of all the stuff you take up a hill can add up. My favourite hill has quite a climb and 2-3 planes, ballast, tx, food, water... makes it good exercise.  

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Brett82

What Tx are you using? Most should have telemetry with Rx voltage as standard, without the need for extra equipment. Set an alarm and monitor the voltage during and between flights.

I use 2/3a packs and I have a switch set to announce the Rx voltage and signal strength. Each time I fly I just flick the switch every few minutes and hear the voltage. Or I can glance at the screen which has the voltage displayed on it. I check the screen before and after every flight. Never had to change a battery on the slope.

Although I did forget to charge my Tx before a comp and that died on me before the end of the last round which left me with a zero score for that flight... Idiot... but again I had an alarm set and got the warning before launching.

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Peter G

Enjoyed the videos, looks like you've got it going well. Ready to run against the clock 😉

Regarding batteries, eneloops aren't the best really. Good overall capacity but not great in terms of their ability to supply peak current draw.  Fine 99.5% of the time but on a windy day if you are carrying a couple of kilo's of ballast, the immediate draw when you whack your brakes out can be pretty significant and that is where the problem can occur (NB best not to whack your brakes out but apply them gradually btw!).

Most poeple moved on to 1600mAh 2/3a Nimhs such as Intellects and Vapex, which were better in terms of current draw and temperature but seemed to go 'off' over time. If you are making your own packs best to charge them individually before making into a pack so they are reasonably 'balanced'.  See a pic of one of my 1600 nimh packs below.

IMAG1313.thumb.jpg.2504773160e7d1a6de533414a016eb3d.jpg

I think most people have now moved on again to Li-ion batteries commonly used in Vape technology, known as 16850 . These are better again in terms of current and temperature and also benefit from very little self discharge over time.  You also get 16500 li ion cells which I have been using, these are slightly smaller but slighly less good in terms of capacity / peak current (I hvn't had any sign of any problems so far). They are 3.6v nominal so 2 cell packs are the norm and individual MKS sbecs are definately the best way to go for dropping the voltage. This is because if a servo stalls, it can fry itself without taking down any others and give you a chance to land. If you just had one uBec supplying them all, this may not be the case. You can fit a balance lead to the Li-ions and balance charge them every now and again like a Lipo.

The last 18650's I bought are Sony's, just 2600mah but very good in low temperatures apparently and good for 25A.

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isoaritfirst

buy a brand - lots of grey cells around.

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satinet
On 22/10/2018 at 20:08, Kyri said:

I flew the needle and it was great fun, no tip stalls or flicks with the reduced throws, and diff on ailerons. It was much easier in higher wind,  and with the ~20mph wind I put about 500g in the wing (two of the brass bars, and maybe 400 in the nose too). I could have put much more in, too. 

I had a great couple of flights, I put a gopro on my cap but the footage is poor, a little too small. I may see if I can get some video out of it.

There were a few events of the afternoon, such as discovering that a flap stick when I did a crow test up high on the first flight. As soon as I noticed it wasn't retracting properly I landed, to avoid draining the battery and losing the plane. The landing was uneventful, and I managed to land close to me so that as soon as the plane was down I could disconnect the battery. I kept the flaps down in the meantime and was able to land in a small bush to avoid the flaps being pulled back on landing (since I could not retract one of them)

At first I thought the flap/s had friction where the flap meets the fuz, as this is where it was snapped and could be oversized. I made a spacer out of layers of tape so that the wing cannot butt up as closely to the fuz. Further investigation also showed it was a small area where the top skin was snagging the wiper, so I taped the flap wiper in that area for the second flight. I will sort that out properly and maybe tape the whole lot later. 

The other "event" was that one of the flap servos moved position. This was after the second landing without retracting the flaps quickly enough. It is the second time it has happened, too, the first being at home when setting up. I had to move the horn on the flap to sort it, after checking it was not a radio problem. The only explanation I can think of is that the plastic horn has moved on the metal spline of the servo when stalling the flap. When trying to move the flap I cant recreate this, and don't want to force it just to prove a point! Maybe I will just change the plastic horn to a new one. Strangely, the flap ends up in a down position (about 20mm lower) which seems odd, and doesn't correlate with my theory in terms of the direction. Maybe I should just change that servo out.

In the meantime here is a pic of the landing. I really like this slope despite the climb up. and want to go again.

regards

Kyri

 

 

 

needle landing.JPG

It could be that the gears are gone in the servo.  What i've found with MKS servos is that one of the gears becomes unglued from the shaft for want of a better description. No gear appears to have stripped but the head of the servo can be moved.

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Kyri
5 hours ago, Brett82 said:

What Tx are you using? Most should have telemetry with Rx voltage as standard, without the need for extra equipment. Set an alarm and monitor the voltage during and between flights.

I use 2/3a packs and I have a switch set to announce the Rx voltage and signal strength. Each time I fly I just flick the switch every few minutes and hear the voltage. Or I can glance at the screen which has the voltage displayed on it. I check the screen before and after every flight. Never had to change a battery on the slope.

Although I did forget to charge my Tx before a comp and that died on me before the end of the last round which left me with a zero score for that flight... Idiot... but again I had an alarm set and got the warning before launching.

I am pretty old school here, no telemetry. I got back into flying last year after a long break, and decided to move to 2.4 but not the full setup giving me the functionality you describe. I can see the benefits though! I have yet to improve my tx but it will happen at some stage. Currently using an old FF7, I make good use of it and the manual trims make good sliders for camber etc but it limits what I can do really. A few compromises which would be sorted with a more suitable tx. I have a taranis that I may look at over the winter. 

 

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Kyri
1 hour ago, Peter G said:

Enjoyed the videos, looks like you've got it going well. Ready to run against the clock 😉

Regarding batteries, eneloops aren't the best really. Good overall capacity but not great in terms of their ability to supply peak current draw.  Fine 99.5% of the time but on a windy day if you are carrying a couple of kilo's of ballast, the immediate draw when you whack your brakes out can be pretty significant and that is where the problem can occur (NB best not to whack your brakes out but apply them gradually btw!).

Most poeple moved on to 1600mAh 2/3a Nimhs such as Intellects and Vapex, which were better in terms of current draw and temperature but seemed to go 'off' over time. If you are making your own packs best to charge them individually before making into a pack so they are reasonably 'balanced'.  See a pic of one of my 1600 nimh packs below.

IMAG1313.thumb.jpg.2504773160e7d1a6de533414a016eb3d.jpg

I think most people have now moved on again to Li-ion batteries commonly used in Vape technology, known as 16850 . These are better again in terms of current and temperature and also benefit from very little self discharge over time.  You also get 16500 li ion cells which I have been using, these are slightly smaller but slighly less good in terms of capacity / peak current (I hvn't had any sign of any problems so far). They are 3.6v nominal so 2 cell packs are the norm and individual MKS sbecs are definately the best way to go for dropping the voltage. This is because if a servo stalls, it can fry itself without taking down any others and give you a chance to land. If you just had one uBec supplying them all, this may not be the case. You can fit a balance lead to the Li-ions and balance charge them every now and again like a Lipo.

The last 18650's I bought are Sony's, just 2600mah but very good in low temperatures apparently and good for 25A.

I will look into the other options, thanks for this detail, I had thought the options were nimh or conventional lipo 2S with  a regulator, but there is a lot more to consider which is nice and clear from your response - cheers!

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Kyri
53 minutes ago, isoaritfirst said:

buy a brand - lots of grey cells around.

Do you mean that grey cells are the generic unbranded, and to go for named brand - it sounds like good advice. I might go for some lithiums with regulators, in due course.

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Kyri
50 minutes ago, satinet said:

It could be that the gears are gone in the servo.  What i've found with MKS servos is that one of the gears becomes unglued from the shaft for want of a better description. No gear appears to have stripped but the head of the servo can be moved.

Thanks for this info, I have a couple of servos in bits that will be inspected to hopefully see whats wrong, if there is any finding of interest I will report back but what you suggest is certainly possible for the flap servo, it seems mechanical. For the smaller aileron servo I think the gears are ok and that the motor is faulty. 

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Skip

Hey Kyri!

I've got a Needle 124 too, they are a fantastic plane!

They are actually quite forgiving on where you have the CG. Mine is at 101mm from the leading edge. Just play with it and bear in mind the effects changing it will have. For example, test your braking each time you change the CG as the elevator compensation will be different and you want to see the effect out in front, not behind you!

Snap flap is your friend if you feel like your elevator isn't effective enough 😊

 

I was flying mine today in marginal lift. I have a 1kg wing joiner that I use ALL the time!

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Kyri

Skip its great to find yet another flyer of this plane, I welcome any setup info as you can imagine! I just had a look at your blog, very interesting. I have a X9D tx but can't tear myself away from old futaba tx's but know I need to do something! Interesting reading on your new tx.

My first outing was in marginal wind, and I look forward to flying it loaded up in more wind, having only done that once since and not with much ballast.

As for snap flap... one of the compromises of my limited tx currently, is that I am not using it. However I am using very slight camber of around 1mm which seems to help, I almost wish I had done that on the first flight in marginal winds but being bitten by it has made me respect it and make sure I keep it moving - its not a light thermal glider despite its size and area. 

cheers!

Kyri

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Skip

I've not tried the Needle without snapflap. A big part of me wants to say be very careful as the speed increases. But I have no experience of flying ANY moulded speed machines WITHOUT snapflap.

Actually interested to see how you go without it 😊

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Brett82

Hi Kyri

Heed the warning from Skip regarding the lack of snapflap... I have never owned or flown a Needle 124 so I have no idea as to how it is with flicking or stalling the tail plane but the use of snapflap only really made sense to me after it was too late with one of my Skorpion's, which is known for flicking.

Almost all F3F planes will flick if you have too much elevator and stall the tail plane. Snapflap simply allows you to use less elevator while still maintaining a tight turn. Different planes like different amounts of snapflap so when you decide to switch over to your other Tx get some advice on throws and mixing ratios. But I would advise you to do this sooner rather than later. Dont get bitten again just because you are attached to your FF7.

Mike Shellim has done an F3F template you can install on you X9D Taranis. It will give you a good starting point and might be worth installing and messing about with it before you move over so you can get used to it. I have put a link to it here, http://rc-soar.com/opentx/setups/f3f/index.htm 

Happy flying

Brett

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Kyri

I know this is the right thing to do.  (upgrade tx) One of the things that has been stopping me, is that I use the mechanical trims as sliders, and throttle on throttle stick. I did try and set up a tx (FF9) with crow on the throttle stick but decided to use what I was used to for the first needle flights at least.  I feared it would be confusing, being used to having throttle at low all the time. If I made the change I don't think I could keep swapping and would have to do the same for F5B with motor on a switch.  

I intend to learn how to program the taranis because it seems very programmable and could potentially get me the same as I have now, which is middle to left rudder is full proportional crow. (then still have throttle on the stick as I am used to for f5b). There may be a way to put rudder on a different channel and mix it with ail to get the right mix at low and higher speeds.  However this is all quite messy so maybe I will bite the bullet and just use the Mike Shellim program for f3f and see how I get on first. It is quite impressive what he has done, and the documentation is excellent. Thanks a lot for the link! Then I would have all the snapflap, variable diff and all the little things which I have not been using, or getting the benefits of.

I also have an old Futaba 9Z which is quite a sophisticated tx, hard to program but potentially can do everything I want for F3F. I think on balance I will go with the taranis and make a start learning how to use it. 

 

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Kyri

I haven't sorted a new transmitter and program yet. I did get to Parlick again today, and flew it with more weight. It could have done with lots more, it seemed very slow compared to the recent comp videos I have seen posted (very impressive!!)

I had 1kg in the wing and around 400g in the nose, but could have had double that. Anyway it is good to get used to it at different loadings. At the east face of parlick it was 25 steady with gusts to 35mph. Here is a picture from the plane:

 

 

 

Capture4.JPG

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