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Old Jun 12, 2013, 05:37 PM
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Joysway Dragonfly / KMP Allstar/Hobbyking Skipper

This model became available recently and came to the attention of Polaris fans for obvious reasons. This thread is merely to discuss the model for what it is and make comparisons to Model Aero's offering rather than the rights and wrongs of who's design it is or is not (we all know it's Laddie's). I can see the subject can't be avoided completely so I shall touch on my views of it first. Though I completely agree the styling and form of it is that of the Northstar, Polaris and Polaris Ultra (it would be hard not to) I don't think it could be said it's a carbon copy of any one of them. The Polaris Ultra is the one most likely to be compared due to them both being moulded foam but even then it's not like the makers have got a copy of Model Aero's moulds. It is all together smaller, the gear layout is different and as far as I know it only comes in RX ready format, whether that is a good or a bad thing we shall find out. I much prefer the blood lines and the looks of the Ultra and if I was in the US I would certainly have gone that way. As it is when you take into account exchange rates, shipping and import duties here in the UK you could almost have two Dragonfly's for the price of an Ultra in the air. I am determined though to set enough money aside so as to be able to make a true comparison myself at some point.

So on to the Dragonfly, as I said it comes RX ready and takes very little putting together. They even state on the box that the ESC and servo's are water proof, more on this later. If the instructions are followed to the letter there are some very strange ideas such as no glue used anywhere in assembly. They intend you to rely on the double sided tape shown in the pics to hold the wings on, I ignored this and used gorilla glue on both the spars and the wing seat. The horizontal stab is intended to stay there all of it's own accord with only the join in the elevator being held together with the small rectangles of self adhesive plastic, again shown in the pics, this was ignored too I did think the spar which plugs into the other elevator half was a nice touch though and seems to work well but I did glue the joint between the two with UHU Por too. In general it went together very easily with all the parts fitting nicely and came together very square without any fettling.

The cowl is very thin soft plastic and is glued in place, I cut this off just to get a look at the motor and check the screws. It has air inlet but no outlet though the firewall is full of holes and the nacelle is open right through to the back. I didn't think would allow enough airflow and would allow water in in the event of a flip which would then have a way into the fuse through the cable channel. At the moment I have just cut an air outlet under the cowl which serves two purposes, cooling and a place to get a finger to the motor for checking temps. I have left the holes in the firewall and the rear of the nacelle open for the time being but will seal them if it shows as a problem. I don't have any motor specs and haven't put it on the wattmeter yet but the stock prop is pretty much a copy of the APC 6x4 I use on the Polaris, the setup seems to provide plenty of power.

Both the elevator and the rudder servo's are mounted in the nacelle sealed in and impossible to get to without surgery. They are connected to the surfaces with some fairly thin and flexible pushrods with a z bend at one end and a quick link at the other. I did a slight mod on the elevator rod as it is pushing for up elevator and I didn't like the thought of it flexing while I'm trying to pull out at low level. I slid a carbon tube over the supplied rod which was a pretty tight fit, I CA'd it in place and heat shrunk the ends too. The aileron servo's are in wells on the top of each wing with a cover glued on over them. Someone in one of the Polaris threads mentioned thinking this was a better setup for keeping the servo's safe from the water, I can say it isn't. I let a friend fly it who preceded to flip it in the water, strange thing is after we recovered it all was fine, he continued with that flight and I did a further two after that on the day. A few days later I took it for a few flights off grass at the local golf course did a preflight, all was good, did the first flight all good, went for a second flight and after about four minutes the left aileron locked hard up at speed and low altitude flipping it over and into the ground. The nose broke off pretty clean with no other damage, a little steam to square things up and a bit of gorilla glue and good to go. I pulled the cover over the servo to find in damp under there so pulled the servo and took it apart, the water proof servo wasn't so water proof. The aileron pushrods are also very long and flexible but as they are top mounted and any flex would only be in the downward moving aileron I let that one go and left it stock, so far it doesn't seem to be a problem.

When it comes to balancing they list it as suitable for 1300mah to 2200mah 3S packs. The suggested cog which is odd in that it is 10mm behind the step seems to work out well in flight. it does sometimes seem to need a good pull off the water but I don't know if this is to do with the relationship of the cog to the step or not. I would think not as I prefer my Polaris balanced around 6mm aft of the step and don't seem to get this problem. The smallest suitable packs I have are 1600's I also have 1800's and 2200's. With any of my packs the prefitted Velcro on the battery tray was too far forward and the ESC which was cable tied to the rear of the tray was in the way. Easy fix, cut the cable tie leave the ESC swinging free and fit some Velcro to the rear of the tray as well as another strap fished underneath the tray. The ESC is a 40Amper and waterproofed by sealing each end of the heat shrink with silicone or something. There is no cooling airflow for the ESC or battery and no provision for fitting a heatsink through the fuse, so far this hasn't been a problem and the ESC has been very cool after flight. You can feel the difference in wing loading switching between my three packs. It handles the 2200's no problem but is much nicer with the lighter packs. The following video was it's second flight with the 1800mah pack.

All in all I think it is a reasonable model for the money, it is fun to fly and it fly's well. I have a feeling that the Polaris Ultra would be a much more professional model, easier to work with if any gear problems should arise and probably have the edge in flight due to the larger wing area. I look forward to finding out for myself in due time.

Joysway Dragonfly (2 min 21 sec)
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Last edited by Aviefly; Dec 13, 2013 at 09:27 AM.
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Old Jun 12, 2013, 07:56 PM
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Thanks for a very interesting write-up on this model. Structurally at least it's quite different from any of the Polaris family.

One comment: The issue isn't so much where the CG is in relation to the step, but the opposite. Aerodynamics establishes where the CG needs to be, then the step position is determined by the requirements of high speed taxi and takeoff. It's usually at or a little behind the CG. Too far back and it gets hard to lift the nose to rotate for takeoff. You use a lot of up elevator to depress the tail and finally the model pops off into a steep climb. But it's not all that critical, as experience with Polaris shows.

Cheers.
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Old Jun 13, 2013, 07:38 AM
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Since this model has a higher wing loading than the Ultra, it appears to fly a little faster even at high alpha, though it appears to be stable enough. How did it behave in repeated touch-n-goes? Can it make high speed barely kiss-n-goes as well as medium speed touches without excessive bouncing or needing a lot of up elevator to get it unstuck from the water?

McD
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Old Jun 13, 2013, 01:39 PM
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Yes from video's of the Ultra I would say it probably does fly a little slower than the Dragonfly. I know it takes a bit more slowing down for landing than my Polaris does and my Polaris is on the porky side too. I've done quite a few normal touch and goes, the usual skim and power away again without allowing it to settle in the water. It handles them pretty well and it isn't particularly hard to avoid the skip. I'm not so sure about high speed kiss-n-goes, not something I really attempt as that's just asking for a skip. I can't put my finger on the unsticking from the water, as I said it sometimes needs a good pull but not always. Now I think about it it's never needed it on a touch and go that I can think of. The cog feels right in flight and the step is 10mm AHEAD of it, wouldn't that make it easier to rotate. I only had the cam with me on the first day out with it but I'll try and get some more diverse video of it when I get the chance.
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Old Jul 23, 2013, 05:04 PM
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First of all, that's a gorgeous flying site you have there!

Thanks Aviefly for your report about this plane. I just ordered one from a UK website. They have it in stock, so I hope to get it soon. Your building instructions are very clear and a guide line for me also. There will be changes along the building process (as you did). Like any pre-fabricated foam model, there are always improvements to make.

Like I said before, I would love to get my hands on a Polaris Ultra too. But it's hard to get it here.

I will report my findings about this "look-a-like" on this thread when I have received (and tested) it. I can't wait...

Regards,
Andre
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Old Jul 27, 2013, 05:55 AM
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Quote:
Originally Posted by Andreotti View Post
First of all, that's a gorgeous flying site you have there!
Yes I'm very lucky in that regard. We have many places just as stunning within a stones throw to fly.

Quote:
Originally Posted by Andreotti View Post
Thanks Aviefly for your report about this plane. I just ordered one from a UK website. They have it in stock, so I hope to get it soon. Your building instructions are very clear and a guide line for me also. There will be changes along the building process (as you did). Like any pre-fabricated foam model, there are always improvements to make.

Like I said before, I would love to get my hands on a Polaris Ultra too. But it's hard to get it here.

I will report my findings about this "look-a-like" on this thread when I have received (and tested) it. I can't wait...

Regards,
Andre
Have you got it yet???
Mine has been putting in a sterling service and going with me most places. It's done a good bit of flying off water but also done a lot off grass, if I lost it tomorrow I think I've had my money's worth out of it. I've flown it in some pretty serious wind too which I reckon it handled pretty well, seemed to get a bit waggy on the tail in it though but looking at the Ultra thread it seems it has that trait too. Not that it matters it was perfectly controllable and great fun even so.
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Old Jul 30, 2013, 08:28 AM
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Have you got it yet???
YES
I got it today!

Funny that the website mentions that the weight is 850 gram. The thrust is 850 gram and the plane itself weights about 420 gram (without lipo and receiver). It is a little smaller then my 100% Polaris, I think it's about 95%

I have just put it together. Easy peasy. I have used glue also. It feels more sturdy then my self build Polari.

The prop was very out of balance and was not mounted strait. So I pulled off the very ugly spinner, mounted the prop right and balanced it. Now it runs smooth as silk (and no more ugly spinner). The ESC looks good to me too, very proportional.

But... I left everything on for half an hour to do some sort of durance test, and it failed

The rudder servo suddenly turned full counter clock wise and stayed there. I tried resetting multiple times and also tried it on the aileron output but the servo is definitely broken.

I am going to do the first few flights without rudder control because I use it mostly on the ground and in water. I will point it into the right direction myself until I have gathered enough guts to put a knife in it and replace the servo. Or someone must have a better idea?

So the only thing left is to get it in to the air.

To be continued...
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Old Jul 30, 2013, 11:50 AM
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That's a shame you've got servo problems already At least there was a reason one of mine went. I suppose that's the problem with ordering one from overseas, I suppose it'd cost you a fortune to send it back for replacement. Let us know how you got on replacing the servo if you pluck up the courage. I don't know how I'd tackle that one if I had to.

Good luck with the rudderless maiden, hope the wind is blowing in the right direction
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Old Jul 30, 2013, 03:04 PM
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That's a shame you've got servo problems already At least there was a reason one of mine went. I suppose that's the problem with ordering one from overseas, I suppose it'd cost you a fortune to send it back for replacement. Let us know how you got on replacing the servo if you pluck up the courage. I don't know how I'd tackle that one if I had to.

Good luck with the rudderless maiden, hope the wind is blowing in the right direction
You're right. Sending it back is not an option. It's whas allready glued together also.

But I have an idea for the servo fix:



I can not fiddle out the servo from the outside without damaging the foam, so I am planning to cut wide around the servo with a very thin knife, get that part out and then get the servo out for replacement. It should be possible to get the part back into place without to much damage.

With a strong flashlight I can see through the foam for a good place to do the cut.
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Old Jul 31, 2013, 01:53 PM
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That looks like it should work Andreotti Can't wait to hear what you think of flying her.

Looks like HobbyKing have got hold of the same model too now.

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Old Jul 31, 2013, 05:14 PM
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That looks like it should work Andreotti Can't wait to hear what you think of flying her.

Looks like HobbyKing have got hold of the same model too now.
I am not surprised. Nice find! It is exactly the same plane but with different decals. Looks like the guy broke the tail section. Sadly I can not read the name.

I fixed the rudder servo allready.

Just like a planned I cut around the servo and took it out:


I opened up the original servo and noticed a short-circuit between the motor and the circout-board. With the small board sticking out I tested the servo again. It worked again. So, with a bit of isolation tape I put it back together and let the power on for about one hour. Normally I would replace it anyway, but it is very secured in the foam, so I will give it a second chance.

Btw, the servo circuit-board looked like it was treated with something like plastic spray to get it waterproof.

There were no labels on the servo, so I can not tell you the brand. But it has these dimensions (bigger then I thought it should be):



Glued everything back into place:


The repair is visible offcourse if you know what to look for.

Last test:




I think it's good to go now.

I even used the balloon:


There's a strong wind blowing here at the moment but as soon as it calms down I will do the maiden. I can't wait too.

P.S. I made a small video of the gap. Sometimes a video is better then foto's:

Joysway Dragonfly rudder servo fix (0 min 18 sec)
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Old Aug 01, 2013, 03:29 PM
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I had the maiden flight tonight. I must say it is not as stable as my other Polari. Maybe because they are much faster. This one wiggles like a drunk duck.

The throw on the controls is out of the box way too high. I reduced it with my transmitter to 50% elevator and 60% ailerons, and that's more then enough. I am going to change that by placing the rodds in another hole in the servo horn.

I am also going to place the ESC further back because I could not get the CG right with a lipo higher then 1300mA

But it flyes like a Polaris. So, I am very satisfied about the first flights. And no more servo problems.

I tested on grass, next time it will be on water. Don't forget my swimming outfit!
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Old Aug 05, 2013, 01:37 PM
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Dragonfly by Joysway - on DIRT, on GRASS & on WATER

Hello Guys !

The Dragonfly is perhaps the best offroad plane ! Cheap and powerful, a must have !

Check our last video edit : Dragonfly unboxing, set up and maiden flight
You will see it on GRASS, on DIRT and on WATER

VIDEO Dragonfly : the offroad plane
http://www.youtube.com/watch?v=swEflG5ypu4

Have Fun & Fly. Over.

www.matterhorns.ch

www.facebook.com/MatterhornsFlyers
www.twitter.com/MFlyers
www.youtube.com/Matterhornsfly
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Last edited by DOCFIGHT; Aug 07, 2013 at 04:31 PM. Reason: obsolete URL video link
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Old Sep 30, 2013, 04:46 PM
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Hobbyking call theirs the "Skipper All Terrain Airplane." It is listed under "Parkflyers and Indoor Flyers".
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Old Sep 30, 2013, 06:13 PM
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I saw it fly at Neat Fair and the Skipper did well.
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