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Banggood Polaris Lander


Shaun Walsh
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I have a Hobbyking Skipper which is great for flying when the field is wet and puddled but wanted something a bit bigger and easier to see so I ordered a PNP Polaris Lander from Banggood, basically a Skipper XL which Hobbyking has now discontinued

.Polaris Lander PNP

The web site says it has a 1300KV motor, requires a 3S battery and shows it with a 3 blade prop.

I received the model on the date stated with no duty charges that I know of so far, great. However, the little bit of information that came with it says that the motor is 1000KV which would require a 4S battery, there are no markings on the motor indicating the KV value. It was also supplied with a 2 blade prop. Have raised a ticket with Banggood. Don't want to return it so I hope its a 1300KV motor or, failing that, that Banggood can send a replacement with the advertised 1300KV rating.

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Shaun, personally I would take with a pinch of salt 'the little bit of information that came with it' bearing in mind that it comes from China and things are often lost in translation. So it may be fitted with a 1300v motor after all. Secondly assuming that it has a 1000kv motor why the assumption that it has to run on 4s LiPo? The spec. says it has an 8x4in prop. Is that is what has been supplied, which would be very small for the motor on 3s, so perhaps a larger three bladed prop is what is required?

The spec. on the Bangood website says it has a flying weight of 1080g (about 2.3lbs). Using the old rule of thumb of 100W per lb equates to 230W which is easily achievable with your motor I suggest? The question is, is the supplied prop suitable and if you run it with a watt meter you will soon find out. The spec also says that a 40A ESC is supplied so in theory would be good for about 350W approx. if it's possible to fit a big enough 2 or three bladed prop.

What I am really saying is why don't you suck it and see, as what is printed in these instructions is often wrong in my experience. (The website also says the product weight is 6kg! I rest my case)

 

Edited By Piers Bowlan on 24/11/2020 09:33:39

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Polaris plans used to be available on the net, so sure they can be built a lot cheaper than what Banggood want.

Having built 3 at various sizes using Depron, can say they are great fun and an easy plane to start float plane flying as its almost impossible to end up inverted in the water if you mess up the landing.

Keeping the water out is the difficult part when using Depron so on the last build I used nylon applied with Poly C which worked well.

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Thanks for the replies, a couple of further bits of information.

I will check the KV value using a tachometer when I get around to building the model.

When I bought the model it was free postage, wouldn't pay the £80 they are now asking.

Will check thrust available and current draw with 2 and 3 blade props although eCalc results show that a 1300KV motor with a 3 blade 8x6 prop gives the best results on a 3S battery.

If it is a 1000KV motor and it doesn't produce enough thrust I will just swap it out for a higher KV motor.

I think the product weight includes all the packaging, the model certainly isn't 6Kg!

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Started to put this together and more frustration, The rudder dropped off but then I would rather it fell off now than in flight, easily fixed with a few cyano hinges. I ran the servos on the servo tester, the rudder was fine but the aileron servo really struggled to the point where the servo was moving not the control rods. Took out the servo and found that the pushrod angle was so acute that the rods were really stiff in the tubes to the point where I couldn't get one of the rods back in. Will need to think about the best way to resolve the problem.

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Two thoughts on how to resolve the aileron problem.

1) Fit twin servos in the wings. Which would mean cutting holes in the wings, running the servo leads through to the fuselage and fitting covers.

2) Use carbon fibre rod instead of wire pushrods. I have tried some 1.5mm CF rod in place of the 1.5mm wire pushrods and they slide freely, probably because they are more flexible and can cope with the sharp bend. If I go this route I shall epoxy the clevises to the end and slide some CF tube over the rod between the fuselage and the aileron to stiffen it.

Any other suggestions?

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More frustration, dry assembled the wings and the wing joining rods are 4mm diameter and fit into the wings fine, however, the holes in the fuselage are 8mm diameter which means that there is no contact/support offered to the fuselage by the joining rods, relies solely upon the glue join between wing and fuselage.

Now need to look for some suitably sized tubing to fit in the fuselage holes. VERY ANNOYING!

dsc_0498[1].jpg

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Posted by Toni Reynaud on 25/11/2020 14:45:46:

Using a hot wire to cut holes to mount the servos in the wing is fairly easy (if you have cut foam before and have the gear to hand). To run the wires, just cut a slot from servo to fus entry point using a sharp blade and a straight-edge and push the wires in edge on.

Think I will try the CF rod method first, if that isn't satisfactory I will go the twin servo route.

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Shaun, I think the idea of the wing joiner is that it is only meant to maintain the dihedral and is free floating through the fuselage with the wing roots locking into the fuselage socket to tie things together. I don't think there needs to be a close fitting sleeve through there.

My Skipper XL came with something like a 1000kv motor which I swapped for a 1400kv Turnigy one to use on 3S.

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Posted by Bob Cotsford on 25/11/2020 15:53:31:

Shaun, I think the idea of the wing joiner is that it is only meant to maintain the dihedral and is free floating through the fuselage with the wing roots locking into the fuselage socket to tie things together. I don't think there needs to be a close fitting sleeve through there.

My Skipper XL came with something like a 1000kv motor which I swapped for a 1400kv Turnigy one to use on 3S.

Quite possibly Bob, but I like to ensure everything is tied together LOL!

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Just run up the motor on the Polaris Lander.
3S battery 8x6 prop as supplied
150Watts
14A
9000RPM
Clearly not the 1300KV motor as advertised.
Have emailed them requesting either a motor as advertised or a partial refund to purchase a new motor myself.


Description:
Brand: RC Lander
Model: Polaris Seaplane
Wingspan: 864mm
Length: 1168mm
Flying Weight: 1050g
Product Weight: About 6kg
Servo: 9gx3
ESC: 40A
Motor: 3632 1300KV brushless
Propeller: 8x4 propeller Click here
Battery: 3S 2200mah or 2600mah T plug(Not included) Click here
Control System: 4CH transmitter and receiver (Not included) Click here
Balance Charger: Not included Click here

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Shaun, what is maximum dia. prop you can fit without it fouling the top of the fuselage. If a 10x6 or (10x8) will fit how many Watts will your motor pull with your 3S battery? Alternatively try a three bladed prop if a 10in prop won't fit - simpler to rectify and cheaper than buying a new motor? Might even work! laugh

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Posted by Piers Bowlan on 27/11/2020 15:04:21:

Shaun, what is maximum dia. prop you can fit without it fouling the top of the fuselage. If a 10x6 or (10x8) will fit how many Watts will your motor pull with your 3S battery? Alternatively try a three bladed prop if a 10in prop won't fit - simpler to rectify and cheaper than buying a new motor? Might even work! laugh

If you fit anything bigger than an 8" prop it would be a very effective circular saw no

Will try a Master Airscrew 8x6x3 but the numbers in eCalc don't look too promising, 200W approx on a 1.05Kg model, I would normally be looking for around 300W on a model of that weight , my modified Riot has over 400W available in a 1.5Kg model. But you are right, try the cheapest option first.

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Posted by Piers Bowlan on 27/11/2020 15:04:21:

Shaun, what is maximum dia. prop you can fit without it fouling the top of the fuselage. If a 10x6 or (10x8) will fit how many Watts will your motor pull with your 3S battery? Alternatively try a three bladed prop if a 10in prop won't fit - simpler to rectify and cheaper than buying a new motor? Might even work! laugh

I don't think a 10" prop will fit based on these pics; according to the RCGroups thread even a 9" will be a squeeze...

On that basis a motor change to around 1300-1400Kv or move up to 4S are probably the only options - this post is instructive...

Edited By MattyB on 27/11/2020 15:39:42

Edited By MattyB on 27/11/2020 15:42:35

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Further update

None of the servos appear to be "attached" to the fuselage, they all move when pushed/pulled. Also the control clevises are made of string cheese, one broke as I was removing it to reattach the rudder.

I despair, for just £10 more (if that) this could have been built to a satisfactory standard, as it is it wouldn't survive its maiden flight.

However, my HK Skipper flies well off a wet strip so I will persevere but no way is this a PNP model unless it means Plug and Pray!

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Posted by Shaun Walsh on 02/12/2020 09:01:25:

Currently playing customer service ping-pong with Banggood, they don't seem to be able to understand the problem with the motor. I will persevere but it may be necessary to raise the problem with Paypal and try to get a partial refund.

Banggood have at last confirmed that the motor supplied is 1000KV, not 1300KV, the item supplied is therefore "not as described". I shall therefore purchase a motor suitable for use with a 3S battery and try to claim back the cost from Paypal.

Has anyone tried getting a partial refund from Paypal for goods which were not as described?

Edited By Shaun Walsh on 04/12/2020 09:52:34

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Well, after I contacted Banggood and pointed out that consumer law requires the item sold to be "as advertised" they came back to me with a perfectly reasonable offer of a partial refund.

Pleasantly surprised, it was a bit of a drawn out process but providing customer service in a language which is not your first language must be a challenge.

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Quick update on my progress with the Polaris.
Have cycled all the servos and so far they seem OK (famous last words).
Have fitted the SK3 3536-1400 motor and after trying a number of props have settled on a Master Airscrew 3 blade 8x6 pulling 34A , 390 Watts on a 3S battery @12320 rpm , 1.35Kg thrust. Using the supplied 40A ESC.
Have been fiddling with the linkages, all the clevises will be replaced for more robust ones.
The rudder and elevator will use the supplied metal pushrods.
I have found that if I replace the aileron pushrods with 1.5mm carbon fibre pushrods, they move much more freely but are a bit bendy so the pushrod ends at the servo will be 1.5mm CF changing to 2.5/1.5mm CF tube outside the fuselage terminated with 1.5mm threaded rod at the control horn, This should be flexible where needed and stiff where it isn't!
Strobon light mounted under the servo hatch.

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