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Northstar mods - Tell me what you think

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Northstar mods - Tell me what you think

Old 06-16-2015, 04:39 AM
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Originally Posted by Cougar429
If you plan to fly from water you need to keep the sharp edge between the bottom and side sheeting or it will make a nice boat.

Believe me.I know this to be true. Back in the 80's I built the fiberglass Parkinsons version and their round edges would not let it break suction. Would not even get onto the step.

What radio are you using? Pretty much all programmable systems should accommodate multiple discreet models.
Huh. Well, if I try it and it doesn't work, I can always rebuild the underside. Or fly it off ground only. Or fit a 'step' along the sides perhaps, and see how that works.

It's a FlySky FS T-4B, for the 4-channel. It's not a matter of programming, I think. The lights I used on my first North Star require a channel to change light patterns. The FS T-4B only has enough channels to run the controls, unless I was inclined to build it without ailerons, which I'm not.
Old 06-16-2015, 01:35 PM
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I was thinking the 6-channel you mentioned flying 001. If programmable you may be able to use another compatible receiver for #2 and program that model separately.

My JR stores 30 discreet models and with the Hansens model the Futaba 32. Should carry my for a bit yet.
Old 06-16-2015, 05:46 PM
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Do not round the corners. I guarantee that it will never lift off from water surface. I know that because when I was asked by Bob Parkinson to design N/S for him to produce as a fibreglass kit. I did that with the sharp edges on the bottom of the fuselage. In order for him to make removing of the fuselage sides from the moulds easier, Bob rounded the corners. First time I tried to fly the model from the water, the model was just ploughing in the water . As soon as the model started to move forward, the water attached it self to the fuselage sides holding it as glue. To give the model more power, we even tried racing ROSSI .60 engine. Did not help. Finally I made removable step with sharp edges that I attached to the front of the fuselage up to the step. Did not help. The water was attaching it self to the fuselage behind the step that still had rounded edges. We gave up and flew from the hard surfaces only.

One more thing. If you are planning to build the N/S with two fins, make sure you have one or two water rudders.
I have one question. I use to be able to post the pictures. Something changed since I can not now.


Originally Posted by RedDwarfIV
Huh. Well, if I try it and it doesn't work, I can always rebuild the underside. Or fly it off ground only. Or fit a 'step' along the sides perhaps, and see how that works.

It's a FlySky FS T-4B, for the 4-channel. It's not a matter of programming, I think. The lights I used on my first North Star require a channel to change light patterns. The FS T-4B only has enough channels to run the controls, unless I was inclined to build it without ailerons, which I'm not.

Last edited by LADDIE; 06-16-2015 at 05:53 PM. Reason: Added sentence
Old 06-16-2015, 07:05 PM
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Laddie, I can confirm that. I had a Fox 50BB on mine, (still have that engine) and brought it with us when we went camping just south of North Bay. We took the kids there every year and thought this would add to the fun. Could not get it to break free in front of the campsite and that's when one of the local boys came up and said "Gee mister. Nice boat"!!!!!!!!

Took it out into the lake with a friends pontoon boat and even generating waves did not help.

Went up to North Bay and found some triangle balsa stock to bond to the edges ahead of the step and STILL could not get it to break loose. Even made a trip down to Bob's place and he ended up no help at all.

Cannot remember what happened to that version, but whoever got it must have cursed me ever since.
Old 06-18-2015, 11:49 AM
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Originally Posted by LADDIE
Do not round the corners. I guarantee that it will never lift off from water surface. I know that because when I was asked by Bob Parkinson to design N/S for him to produce as a fibreglass kit. I did that with the sharp edges on the bottom of the fuselage. In order for him to make removing of the fuselage sides from the moulds easier, Bob rounded the corners. First time I tried to fly the model from the water, the model was just ploughing in the water . As soon as the model started to move forward, the water attached it self to the fuselage sides holding it as glue. To give the model more power, we even tried racing ROSSI .60 engine. Did not help. Finally I made removable step with sharp edges that I attached to the front of the fuselage up to the step. Did not help. The water was attaching it self to the fuselage behind the step that still had rounded edges. We gave up and flew from the hard surfaces only.

One more thing. If you are planning to build the N/S with two fins, make sure you have one or two water rudders.
I have one question. I use to be able to post the pictures. Something changed since I can not now.
I'll try putting a removable step all along the side at some point. It's not a hurry though, since I can't fly my Northstar at all right now, unless I manage to take it to one of the clubs that are, at closest, 2.6 miles away (a long way carrying a multiple kilogram plane, I imagine). This is one more reason why I'm building a second one that I should be able to fly in much more nearby open spaces without threatening parkgoers with what my Dad likened to a lawnmower with the blades facing forwards, flying through the air. By comparison, an EDF jet is more like a strimmer - you can only hurt yourself if you deliberately stick your hand inside it.

I'm definitely putting two rudders on it. I'm leaning towards using seperate servos, probably on a two-way splitter (getting a five-way splitter for the three EDF jets I'm going to fit so they'd all run on one throttle control has opened my eyes to the possibility of such things.) I'm also considering fitting a thrust-vectoring system, having seen a video on YouTube where someone made a really simple one for their EDF jet.

What was the question? Or was that aimed towards the forum moderators?


Anyway, paint scheme:

Based on:


The tail booms will probably be further apart than shown - depends on the surface area of the original design's horizontal stabiliser.
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Last edited by RedDwarfIV; 06-18-2015 at 11:51 AM.
Old 06-18-2015, 12:36 PM
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RedDwarphIV, not sure if there is a supplier your side of the pond, but a possibility may be the Polaris or Polaris Ultra, (smaller foamie electric versions of the Northstar) if you wanted something to fly in confined areas.
Old 06-18-2015, 02:56 PM
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Originally Posted by Cougar429
RedDwarphIV, not sure if there is a supplier your side of the pond, but a possibility may be the Polaris or Polaris Ultra, (smaller foamie electric versions of the Northstar) if you wanted something to fly in confined areas.
Yeah, but that wouldn't keep me occupied for very long building it. Besides, I've already started buying the parts - three 70mm EDF jets (with ESCs), three 4-cell LiPo batteries, balance charger, battery low voltage buzzer and a few other things. And... well, why have a small plane you can fly in the park when you can have a big​ plane you can fly in the park?
Old 06-24-2015, 12:45 AM
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Managed to get one of my EDFs running. Well, technically two, but I used the same ESC for both. All three batteries have arrived, and I'm now waiting for the third EDF and the balsa wood to arrive. I've already started building a mounting for the EDFs.
Old 06-24-2015, 03:11 AM
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I did not believe it possible to run two brushless motors from the same ESC.
Old 06-24-2015, 03:14 AM
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Originally Posted by Cougar429
I did not believe it possible to run two brushless motors from the same ESC.
Oh. No, I swapped the EDFs. I just wanted to make sure my soldering on the bullet connectors worked. What I meant was, I haven't tested the second ESC yet. I think.
Old 06-24-2015, 04:48 AM
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O/K. Good thing you do the soldering yourself. A lot of failed ESC's I check have substandard soldering hidden under the heat shrink or covering.

I also am personally not a fan of lead-free.

Can't wait to see pics of this one.
Old 06-24-2015, 09:22 AM
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I only had one sheet of 4" balsa left from the original kit/(what-I-got-off-eBay-because-the-kit-had-stuff-missing), so I can't do the entire EDF mounting yet - just one piece of it. It's a 4-inch sheet with 3-inch sheeting glued to the back to reinforce it. By putting it against the top of my first Northstar, I could see that it came to about the same height as the (raised) fuselage.

Oh, I'm also considering Thrust Vectoring. I was thinking that it would help with takeoff - one EDF northstar I found while researching EDF Northstar modifactions had trouble lifting off from water. Since I'm basically running air from intakes all the way to the end of the fuselage, rather than putting the jets on wing nacelles, I think I have an opportunity to take advantage of how much leverage it would have. The air nozzle would be a comparatively long way from the centre of gravity. This would likely also increase pitch control - something Northstars are often mentioned as being sluggish in.
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Old 06-25-2015, 03:41 AM
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Trying to figure out your description of the intake ducting. Also, instead of moving the EDF units themselves, (requiring them to be close to the exhaust point themselves), if properly controlled the exhaust flow can be redirected. My friend had a turbine jet with that feature.

As for sluggish pitch control, this is the first mention I know of and can think the only instance would be at low throttle and high alpha where the wing could blank the tail, (an issue with full-size aircraft, as well). Throttle up should take care of that on the original design as the elevator was immediately aft.
Old 06-25-2015, 05:32 AM
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Originally Posted by Cougar429
Trying to figure out your description of the intake ducting. Also, instead of moving the EDF units themselves, (requiring them to be close to the exhaust point themselves), if properly controlled the exhaust flow can be redirected. My friend had a turbine jet with that feature.

As for sluggish pitch control, this is the first mention I know of and can think the only instance would be at low throttle and high alpha where the wing could blank the tail, (an issue with full-size aircraft, as well). Throttle up should take care of that on the original design as the elevator was immediately aft.
I wasn't planning on moving the EDF units. I saw a video on YouTube where someone made a movable EDF jet, and they said the rotation was screwing it up. As you say, it's better to control the exhaust.

Basically, my new plane with look something like a DeHavilland Sea Vixen, with the end of the fuselage having the engine exhausts, and the tail coming off twin booms attached to the wings. If I put thrust vectoring at the exhaust, it would have much more leverage than If I put thrust vectoring on a wing-nacelle-mounted EDF.
Old 06-26-2015, 05:23 PM
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The top is left open so I can access the mount's attachment points, if I need to put in or take out the screws that will hold the jets in place. I will probably add a removable top to this later.

All three ESCs have bullet connectors now, but only one of the EDF jets has them. I'm waiting for some to arrive in the mail so I can fit them on all the EDFs. I'm also waiting for a new balance charger, since my old 2-cell charger has disappeared somehow.
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Old 10-20-2015, 02:49 AM
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Red Dwarf, any progress?
Old 03-11-2016, 03:47 PM
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Since I decided to go electric with my Balsa USA Northstar kit which does not have the locking tabs shown on the original plans, I thought I would use some of the weight savings to put the rudder and elevator servos in the nacelle. I had some leftover carbon fiber strip (10mm wide x .56mm thick) which looked useful to provide some some additional support for the upper fin. The idea evolved and I decided to use the two forward fin supports as the primary support structure for the elevator servo, which is mounted to the underside of the horizontal stabilizer. The horizontal stab, elevator, and upper fin will be removable to make it easier to transport the airframe.
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Old 03-11-2016, 06:08 PM
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Looks a lot like mine. I opted for only the elevator and throttle servos in the pylon.
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Old 03-14-2016, 05:15 PM
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Cougar,

Did you waterproof the inside of your Northstar? If so, any suggestion for what the use for a lightweight waterproofing?
Also, why the cover on the back of your Nacelle?

Bob
Old 03-14-2016, 05:37 PM
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I used Water-Based Polyurethane in a spray can to do the fuse and wing before bonding them together and installing the top skin. I did the same for the Seamaster before re-covering.

NOTE: I used a supplementary brush on bonding for the covering along the edge where it met the painted bottom skin. Prevents water from peeling it away. Would have to go looking if you want the info.

That back piece is more for looks than any real function.

Well, may have to take a hiatus. Just sold my Northstar to my friend. I had built him the second airframe and he still has that hanging in his hobby room. No time to finish.

As it is I have 3 other amphibs and am working hard on getting the nitro Seawind ready for this season.
Old 03-16-2016, 11:15 AM
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Cougar,

Thanks for the information regarding waterproofing. For the seams I will use the sticky stuff that sig sells. I have used it before and it works pretty well.

You mentioned that you have a nitro powered seawind that you are prepping to fly this summer. I assume it's the 71" Great Planes version. I have been flying mine with electric power since 2008 and I have been working on it off-and on this winter to fix a variety of problems that come with age and abuse (it was my first water plane). I am working to devise a patch for the interior rib back by the pylon which cracked, making the pylon a bit loose. My approach now is to use carbon fiber strip, reinforced by carbon fiber tube and attached with epoxy.

Question- how does the Northstar fly in comparison to the Seawind?
Old 03-16-2016, 12:20 PM
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Mine is the NitroPlanes version. Approximately the same size, but there are some changes. Along with no ability to mount retracts one notable is a wing tube rather than the extruded spar GP uses. I added a second C/F tube where their original small wood alignment pins were located to more accurately hold incidence and share the load, along with hopefully stopping the entire wing breaking free under torque such as flap extension.

I also identified where the pylon had the most flex and installed a bulkhead. As I intend to have the tank down in the fuse with a pump feeding the Saito 100, (will test this out on the engine stand first) this gave me a place to mount the throttle servo. Some other major changes were to use nyrod for the elevator and rudder, rather than have servos bolted to the external skin. The design had interference between the elevator linkage and rudder right out of the box! Now everything will be up front. The elevator nyrod is 4/40, the largest you can buy and very strong. I have the horn now on the top so it pulls for up, (I don't intend for much inverted as it will be flown scale). Much better arrangement for this linkage type. On that note I also built a new elevator as their stock unit was very soft balsa and bent like paper.

There are other differences between the two machines. I looked at the G/P first and will still grab one if the price is right, but they have some problems with fuse separation and an incorrect step placement that would have to be dealt with. Not sure if they suffer the same problem with inadequate bonding. I had already reskinned the wings and redid the rather dubious glue job. It looks like they preferred something akin to contact cement, which did not penetrate very far, nor hold that well. For peace of mind I did the same to the horizontal stabs and was glad I did. The C/F rods were flopping in the ribs and again very bad glue bonds.

As for flying qualities, that assessment will have to wait till I get the Seawind airborne.

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Old 03-16-2016, 09:16 PM
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Good luck with your Seawind. I know with my Great Planes Seawind the primary problem was getting it off the water; it had a horrendous tendency to porpoise on takeoff. For awhile I found that the only way to get it off the water was to let it bounce twice and let cut the power at the high point of the third bounce and then gradually add power and pray that it was high enough to keep flying. Eventually the solution was to add significant, about 3 deg, downthrust and a much more powerful motor. This combination worked well and I have been happy with the airplane ever since. I sure wish Great Planes would make the airframe lighter, beef up the internal structure with carbon fiber, and re-release it.
Old 03-17-2016, 05:23 AM
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From what I saw online guys had much more luck moving the step back a bit. Perhaps double sided tape and some blue foam cut to shape on your could confirm if that works before permanent mod.

I had the Parkinsons fiberglass Northstar back in the 80's and the fuse/side interface was rounded. Never did get it off the water,
Old 03-17-2016, 10:44 PM
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With the added downthrust the Seawind is so well behaved getting off the water that I have shelved any idea of relocating the step. It is just not necessary to get a smooth, controlled takeoff. I have seen quite a number of posts by others who swear that relocating the step is the way to go but at this point it is not required for my style of flying. If it could be demonstrated that the aircraft could handle much rougher water I might consider the mod but at this point if the water is rough I just fly something else or not at all.

I am very interested in how well your NitroPlanes Seawind performs.

Last edited by Bob93447; 03-19-2016 at 02:25 PM.

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