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Northstar mods - Tell me what you think

Seaplanes Aircraft that typically take off and land on water...radio control seaplane discussions are in here.

Northstar mods - Tell me what you think

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Old 05-03-2017, 10:47 AM
  #576  
RobKit
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That is a considerable altitude for any aircraft,, And have to be considered for TO and landing performance,
even a 737 have to adjust its TO/landing distance
I have built 3 Polaris (RIP),,have two Ultra/SkipperXL/Lander that I play with and have been "hooked" on that design for years now..

The NS I currently have (still alive) is probably about 4.5-5Kg when fully loaded with the biggest motor and one 5amp 90C lipo pack,, but it gives me only 4-5 minutes flight time.. If I am not careful itīs only 2-3 minutes I am probably very close to burn everything up.. What I would like to do with the core I have is to build a NS as light as it is possible and to add a dimension of versitility by being able to swap between electric and a glow engine.. however it means that some "thinking" have to be done before i start to build it.. I am planning to put the fueltank at the step/CG and also use the same space for "sliding" in a lipo pack when using a electric motor.. So if I use a 350gram electric motor (a Gartt 1220Kv, 2100watt)
i will have about 200gram lighter tail (from the glow engine) that will mean roughly one more lipo pack that can be added in the front.... Well this is the ideas I have,, but need to think it through and build it LIGHT !!
//Rob
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Old 05-07-2017, 08:41 AM
  #577  
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Rob,

I believe you need to rethink your strategy on the lightweight NS. If it is balanced correctly and you remove 200 grams of motor weight, which is behind the cg, you need to remove weight forward of the cg to keep the balance correct. Overall it makes the airframe lighter but it is not in the direction of adding battery capacity. On the other hand, if you move the elevator and rudder servos to the pylon and move the aileron servos to the wing, then the forward compartment becomes a giant cavern for lots of batteries

Bob
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Old 05-07-2017, 11:04 AM
  #578  
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Originally Posted by Bob93447 View Post
Rob,

I believe you need to rethink your strategy on the lightweight NS. If it is balanced correctly and you remove 200 grams of motor weight, which is behind the cg, you need to remove weight forward of the cg to keep the balance correct. Overall it makes the airframe lighter but it is not in the direction of adding battery capacity. On the other hand, if you move the elevator and rudder servos to the pylon and move the aileron servos to the wing, then the forward compartment becomes a giant cavern for lots of batteries

Bob
Yes you are right,, donīt know what I was thinking ..
(I was not drunk so canīt use that excuse)

As I said, have to plan this carefully..
Step one is to figure out where the weight "traps" are and how to make it even lighter,
I read somewhere that It should be possible to come down to 4.5--5 pounds.
//Rob
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Old 05-08-2017, 09:03 AM
  #579  
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Rob,

The thread you are looking for is called "Northstar Redo" over on RCG. The author is pmisuinas. His NS came in at 5.5 lbs with a 4 cell lipo in place. Most of what he did was substitute foam for balsa with some Carbon Fiber reinforcement.

Bob
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Old 05-09-2017, 03:16 AM
  #580  
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Thanks, I read it long time ago and finally found it again,,
What happened with the project, did it ever fly ?

I will certanly look in to how to combine materials and make a "hybrid" I would love to go for
Glow and Electric versatilaty in one and the same model,, if at all possible without too much difficulty,
One note I took, was a comment from Laddie to balance it "on the step" would love to know more about how it flies there.. Maybe I will test it on my "way too heavy electric version" while itīs still in one piece. //

Thanks for your interest in my project// Rob
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Old 05-22-2017, 09:21 AM
  #581  
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Northstar off the water,

After a few successful test flights of my Northstar flying off of snow, I was able to do the "water maiden" over the weekend. I'm flying with a Hyperion 3026-970KV motor driven by a 5s 4500mah battery. I also used a Master Airscrew 10x7x3 blade prop and balanced it about 1 cm in front of the step. It flew well and rolls nicely without dropping the nose. My primary problem is the rapid heating of the esc; I need to either install vents or put in a small fan. I also noticed that cross-wind takeoffs are a bit tricky as it has a tendency to roll in the direction of the wind. The addition of a water rudder is in order since the turning radius with the air rudder is limiting.

Bob
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Old 05-28-2017, 09:40 AM
  #582  
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So, it's been 2 years since my last post. What have I done?

Well... until about two weeks ago, nothing. I had other projects to work on. But a fortnight ago was when, as I was building an RC ship, I was looking under my bed for an ESC to use, I found the box of unused parts. I looked at the balsa ribs and the EDF mount and thought "these are rubbish". The ribs had been difficult to cut, easily broken and several had to be doubled up to be strong enough. The EDF mount was damaged and in several places it wasn't even straight.

So, I took to AutoCAD, got out my plans, and started modelling the parts. The result so far is this:
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So, I've got the wing ribs, nosecone, some of the wing panels, a load of wing spars (these can be acetone welded together to make them longer, or cut shorter), wing leading-edge pieces (x12, half of which failed 90% of the way through the print so will be used either behind the strakes or as structural support elsewhere.) I am currently printing the rib cap strips and the trailing edge pieces.
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Old 05-31-2017, 08:22 AM
  #583  
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Update:
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Old 05-31-2017, 09:04 AM
  #584  
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Good Progress! What's the purpose of the extra structure in the center section?
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Old 05-31-2017, 12:51 PM
  #585  
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Originally Posted by Bob93447 View Post
Good Progress! What's the purpose of the extra structure in the center section?
That would be 2.4mm balsa covering in the original design. Here, I printed out coverings that were largely empty space since ABS is much stronger than balsa is. To borrow an image from the ElectricDan blog:
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Old 06-01-2017, 01:39 AM
  #586  
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Originally Posted by RedDwarfIV View Post
That would be 2.4mm balsa covering in the original design. Here, I printed out coverings that were largely empty space since ABS is much stronger than balsa is. To borrow an image from the ElectricDan blog:
Attachment 2218028
Interesting project !!

So if I understand it correctly it is ABS plastic you are using ?? can you share the spec ?
I suppose you are looking for a stronger & lighter NS in the end, hope you will find the time to finish it soon.
Please keep us posted of your progress .

//Rob
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Old 06-01-2017, 05:28 AM
  #587  
RedDwarfIV
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Originally Posted by RobKit View Post
Interesting project !!

So if I understand it correctly it is ABS plastic you are using ?? can you share the spec ?
I suppose you are looking for a stronger & lighter NS in the end, hope you will find the time to finish it soon.
Please keep us posted of your progress .

//Rob
ABS is one of the two most commonly used 3D printing materials. Its harder to work with than PLA, but its much stronger, doesn't melt in hot cars, and can be acetone welded together to create joints that are just as strong as the rest of the part. You can also use acetone to turn failed prints or scraps into a cement that has numerous uses, and not just in 3D printing either. I've used it to insulate parts where two power cables are connected on my electric bike.

Compared to my last Northstar? I'm racing ahead with the construction on this one. And yeah, at the very least it should be stronger than a balsa version. Much easier to modify too, since you just design and print any custom parts you need.

Another advantage of plastic over balsa is that it can get wet without issue. It will never rot or warp because of water, which is kind of important for a seaplane.

Last edited by RedDwarfIV; 06-01-2017 at 05:34 AM.
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Old 06-02-2017, 08:48 AM
  #588  
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Pontoon:
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I've almost finished the right one too, just needs some triagular support beams and the rear underside covering. In hindsight, I should have made 4mm covers instead of 2mm. I didn't realise 2mm would tear so easily. Still, when its fibreglassed that will not matter.

Something nice is just how easy thin plastic will bend, unlike balsa. This was a daunting task on my previous, wood Northstar, but here it was a breeze. In fact, the general ease of working with ABS (especially how fast ABS cement sets) is making this entire build a breeze.

I'm going to redesign the fuselage bulkheads to make the end result more like Yakdude's model with its 30* sides. I've also been thinking about increasing the width of the step to help with water stability.

Wing mass so far is 784 grams.That's 1.7 lbs.

Last edited by RedDwarfIV; 06-02-2017 at 09:15 AM.
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Old 06-03-2017, 06:21 PM
  #589  
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Bulkheads and triangular support beams have been printed. Not entirely sure yet exactly how I'm going to use the triangular beams, as they can't go wher they would in the original design. Maybe I'll saw the bottom corners off and put them there instead. It would increase the support on the part of the fuselage that most needs it, after all.

The F2 bulkhead has a protrusion intended to hold a brass tube that would allow mounting the original landing gear. I won't be using it this time, but it's nice to have the option.
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Old 06-04-2017, 12:36 PM
  #590  
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Very interesting build approach,, Looking forward to the progress,,
What is your plan for the rounded surfaces ? can that be done in the printer ?

Maybe you can make this in to a commersial production ?

//Rob
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Old 06-04-2017, 12:45 PM
  #591  
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Originally Posted by RobKit View Post
Very interesting build approach,, Looking forward to the progress,,
What is your plan for the rounded surfaces ? can that be done in the printer ?

Maybe you can make this in to a commersial production ?

//Rob
Rounding can be managed with ABS cement and sanding. Or I could print off long rounded beams I suppose.

Any production would be entirely dependent on Laddie Mikulasko's input as it is his design (with some small modifications.) Further, a 3D printer really isn't suited to mass-production. If I were to sell anything, it would be the STL files so people can print it off themselves. Further, I wouldn't be competing directly with an established model-making company.
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Old 06-06-2017, 07:37 PM
  #592  
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That W3 rib wasn't straight, so I added some structure to it. The landing gear mounting and capstrips would have solved that anyway, but I thought I'd try and prevent any warping that might occur since those features aren't going to be added for a short time yet.

The fuselage sides turned out to be half the width they need to be, so I'm printing off a second set to double them up. On the plus side, they were easy as pie to fit since they bent so easily, while the doublers will also be easy to fit but once fitted will add some rigidity to it.
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Old 06-07-2017, 07:55 PM
  #593  
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Ignore this post. I was testing the image tag and thought I could delete it afterwards.
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Old 06-08-2017, 01:16 PM
  #594  
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RDIV,

I am enjoying watching your progress. It looks like an interesting way to build planes. What are you planning to use for covering?
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Old 06-09-2017, 04:49 AM
  #595  
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Originally Posted by Bob93447 View Post
RDIV,

I am enjoying watching your progress. It looks like an interesting way to build planes. What are you planning to use for covering?
Thanks. And I plan to use Monokote. I have some left over from my last Northstar project.
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Old 06-09-2017, 02:41 PM
  #596  
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I have, since this picture was taken, removed the F-3 bulkhead in order to fit the nose gear mount.
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Old 06-11-2017, 05:06 PM
  #597  
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With the twin tails reducing the size of the ailerons, I thought it would be a nice idea to give some added control authority in another way.

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EDF thrust vectoring.

If I mount four EDFs, then the centre two can be fitted for pitch and the outer two can be fitted for roll. I see this as being much easier that giving pitch and roll to all four engines.

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Old 11-24-2017, 12:21 PM
  #598  
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I've been wanting to build a Northstar for a while now and this morning I took advantage of Balsa USA's holiday sale, so I've got a kit on the way! The only problem is I'm in the middle of a 1/3.5 scale sailplane build and won't be able to build the Northstar for several more months.

So what is the current consensus on mods for this? I'll be building it for an OS46AX. One of the earlier builds (Predmech/Yak Dude) in this thread angled the upper fuse sides in 25-30 degrees and added winglets to the tip sponsons. It really made a dramatic difference in the appearance, so I'll likely do that to mine as well.
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Old 01-30-2019, 05:51 AM
  #599  
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Default North Star edf

Hello,

hope you you don’t mind the intrusion. How is the north star edf? Any pictures?!....

all the best, Adam
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