Yak Dude

Looks great on water. Did you move the C/G aft a little? If so did it help? Wes

LADDIE

Congratulation. Great looking model. I am glad that you sorted out the radio problem. I like your neat building and finishing.
Laddie.

pacomb

Hi all

I always wanted a NorthStar in my garage.... but just never got around it.... Last week in a spanish forum a guy published a thread with his NS, because hi wanted to sell it. It was 60% built from an original Balsa Usa kit. He has moved into big gasoline biplanes, so was not going to finish the NS. At 40 eur, that was a deal I could not miss....

The construction is well done because the owner had experience building kits, jut need to go over some seams, with fresh glue.

I have read all the 11 pages, uffffffff, and have convinced my self of the following:
-Will put 2 micro servo at the rear for the throttle and the elevator
-Will be using a removable elevator surface for easy transportation
-Fiber glass 2 layers on the button fuselage
-Reinforce with some fiber glass the inside of the fuselage, where bulkheads glue to the lower part of the fuselage

Still thinking how to cover it... monocote or painted fabric

Just wondering, I have recently managed to get some used aluminum sheets used in big printer stores. They are very thin, possibly about 0,2mm. I use them to hold down delicate parts on my lathe. People use them to cover war birds planes. Could it be possible to put fiber glass on the button fuselage, and a sheet of aluminum?? would give a great looking, alu is strong, could give razor edges, and if wax applied would be great for grass takes off.... what do you think???

A picture of the actual situation of my plane.

Paco

Cougar429

My Feedback: (3)

I would stay away from using aluminum on the bottom of the plane for the sake of radio reception. Glass cloth should be strong enough and less likely to deform from impacts, (along with being easier to repair).

Cobra II

I recently picked up a Northstar from a friend. It is built and ready for radio installation. However, in reviewing photos in this thread, I see that mine was built without the forward wing root strakes. How much will this affect the flight characteristics? If someone could give me the dimensions of the strakes, I could add them. One other thing. I assume that the CG balance point is based on a full fuel tank, right?

Cdallas2

Wes - I moved the CG from about 16 1/2" (from the TE of the wing) to 15 1/4" (with the tank empty) and that made all the difference. Trimmed out okay and inverted became possible.

Laddie - Thanks for the kind words. I was just a kid when I saw the NS in RCM and I've always wanted one of my own. I've previously had a Laker and a Force 1 but the NS was always my favourite. I'm thinking of doing another one and this time going electric similar to yours.

LADDIE

I use to have one NS without the strakes. I could not tell the difference between two.
When I was designing NS I had two reason to add these strakes.
The first one was to reduce the chance of the water entering the radio compartment, specially when taxing in the cross wind when the waves are hitting the sides of the fuselage.
The second reason was to make the model to look more like F-16.
Laddie.

cavandish

I use to have one NS without the strakes. I could not tell the difference between two.
When I was designing NS I had two reason to add these strakes.
The first one was to reduce the chance of the water entering the radio compartment, specially when taxing in the cross wind when the waves are hitting the sides of the fuselage.
The second reason was to make the model to look more like F-16.
Laddie.

Read more: http://www.rcuniverse.com/forum/m_74...#ixzz0qURVKL51


Laddie
I don't doubt you for a second, as you did create the plane ! The interesting thing is that my Balsa USA instructions say not to omit the strakes, as they add so much to the flying ability !

when I built mine, fitting these was one thing that I was not looking forward to, but with cyno, kicker , and the correct timber, it is a really easy job. I found the hatch construction to be the hard part.

Cobra II

Laddie - Thanks for the feedback. I have admired the Northstar for a long time, just no time to build. I have a clear plexiglas sheet screwed and gasketed for access instead of a hatch, so hopefully the water won't be an issue. If that is the strakes only purpose, I may add some simple 1/4 balsa ones for good measure. Hope it is as much fun to fly as my Polaris.

Cougar429

My Feedback: (3)

Thought I'd add a couple of pics of the Northstar in her favourite element. Cut me some slack, I left the gear on for this as it was going directly from the water to sitting and drying on the patio.

Cougar429

My Feedback: (3)

Well, finally had the chance, (Translation: got up enough nerve) to maiden the Seamaster and Northstar last weekend. First flight for both could have been better, with a motor sag on the Seamaster having me dump it into the corn. Made on hell of a lot of noise, but other than corn leaves wrapped around the prop the plane was intact.

As for the Northstar, that one also was a bit more work than I expected, with the plane out of trim, (for some reason needs left aileron) and the engine surging, (you can hear it in the vid starting at 2:30). Still, the EVO 46 had no problem hauling it airborne. There was a serious dutch roll on take off. Laddie recommends adding more nose weight and I will go with that before heading to the field again. Personally, I think a lot of it was my being too aggressive yanking it off the ground since landing with high alpha was not so bad.

Back on the ground I found the HS needle clip had broken off, allowing the mass of the needle to vary the mixture. Solved it with a quick fix with a short piece of fuel tubing.

I did a vid flight with my friends combat Corsair and made the decision to try another with the 'Star before a weather front arrived. Not the best plan, as the second flight almost ended in disaster. On takeoff I let the elevator drop too soon and almost went for a corn dinner. Motor surging was gone, but a few minutes in the front hit and the wind shifted 90 degrees to the runway, picked up to 20+ and was increasing by the second. I could have landed into the wind if I did a healthy walk to the turn around at the end of the runway, but so far the plane was handling the wind fine and I wanted it on the ground NOW. As it came level with the top of the corn things got interesting in a hurry. Bent the main gear up slightly, but easily fixed and no other damage. Unbolted the tail and loaded it back up just as the rain hit.

I have to say I've never had two consecutive maiden flights with engine problems like this, (three if you count the linkage breaking off the Saito in the Skybolt the week before, allowing the engine to wind up full. I've put more than a dozen flights on that one, so can't count it as a maiden. As it normally only needs 1/3 to 1/2 to do everything, you can see how this would up the entertainment value.) Had to plant that one over on her nose as it's the only time the engine decided to continue to run when starving for fuel).

The problems have been overcome and now all 3 engines run full tilt with no issues. So, all told I've come home with them in the same number of pieces as they arrived and consider myself lucky.



[youtube]http://www.youtube.com/watch?v=fVapqznX0fQ[/youtube]

hattend

My Feedback: (20)

What's the little one. Does the Northstar come in a smaller size?

Don

Cougar429

My Feedback: (3)

It's the electric version from Model Aero, called the Polaris :

http://www.modelaero.com/

kloper

I made a modification to charge the flight battery with out removing the canopy as follows:

1) by removing the cap and plastic threaded part from a 1/2 pint heavy cream container.

2)I than mounted the threaded piece of the container to a balsa plate and installed the charging jack in side of the threaded plastic part.

3) I than mounted the assembly ( the balsa plate, the charging plug and the plastic
threaded piece ) to the top front portion of the fus. just above the battery.

4) I painted the cap gray to look like a radar antenna. Since the cap will keep the heavy cream from coming out of the container, theory tells me the cap will keep water out if screwed on tight.
If any one would like a picture let me know

cavandish

while you are at it, put your on /off switch in there.

Cougar429

My Feedback: (3)

Sounds like a great idea. Would really like to see some pics of the rig.

Have to love how people solve some things.

aa1a

My Feedback: (4)

Yes. pictures please on the watertight charge jack!
I am getting ready to build my second Northstar. I lost my first one last winter. I am considering buying an old YS 45 for power. It has a pressurized fuel system and allows you to put the tank in the fuselage on the C.G. I've seen one at a float fly with this setup and it flew great. Anyone have experience with this setup? Pros? Cons? Does the desired C.G. remain in the same location?
Thanks for any help you can offer.
Jim

idigrc2

On page 5 and 6 are pictures of my northstar framed up . Iam using a Y.S 45 for power. the fuel tank is mouted on c.g and I used heavy wall plastic tubing to transfer the fuel from the tank to the pod. Also I mounted the throttle and elevator servos on a rail so that they are easy to access. I've been meaning to finish this project just been busy with life and the economy hasnt helped things much ether

cavandish

I flew mine from the ocean yesterday.
the tide started to go out during the day, leaving wet mud, she flew off this surface really well too.

Goldenduff

Hello everyone, I have the northstar plans and am scratch building it. I am using a .57 (J'EN) which is a bored out .40. Anyhow, thinking of using a perry pump for two reasons.
1) fuel tank nearer CoG
2) less stress on engine pod.

I will also be using a micro servo on the throttle to reduce rear weight as a normal is overkill. Is a micro servo sufficient for the elevator?

Any other mods? The plans will be used for general dimensions so dont really need advice regarding formers etc.
Some suggest elevator can be made bigger- any thoughts?

Re; strakes I hear the theory is giving the wing two stalling points thus easing flying. Some say no change, is it worth the effort?

Any other hints would be great, thanks Adam

Cougar429

My Feedback: (3)

Although I use micros for throttle on almost all my nitro planes, with the size of the craft and the fact the elevator is in the direct prop blast would prevent the use of only a micro servo there.

There are several that have mounted the fuel tank down at the CofG. I did it in one of my earlier versions with a Perry pump and it ran fine. Only caution would be to use plastic tubing from the tank up to the engine bay since it can be heated and curved to fit much easier and long term there are no fatigue issues, (I use aquarium air tubing). My next Northstar will likely have it done that way again and I will add a hatch to troubleshoot, service or replace any of the tank components.

The added advantage would be a larger tank. I only had room for an 8oz tank behind the firewall. Am able to get 13 min WOT with the EVO 46, but will always be more concerned with time than any of my others.

According to the designer Laddie Mikulasko, those strakes are necessary for proper flight dynamics. Just the size is a bit important as too large creates a tendency to nose up when pushing high alpha flight.

If you are scratch building, I would recommend you look at what some have done, shorten the tail slightly and raise the engine pod for prop clearance. This would have helped in my case as the removeable tail required more weight in the nose than I'd hoped for to balance.

Goldenduff

Thanks for the input.

Will use micro servo for throttle
Standard size for elevator- would you enlarge the elevatro?
Will put rudder servo up front for weight purposes, not concerned about play/response in the rudder.
Have already slightly shortened tail section.
Had thought about taller engine pod but some say it would increase turning moment- ?Icould just add some more down thrust?
Will stick to wing aerofoil and strakes.
Regarding fuel tubing- I was going to use standard tubing, is this liable to kink? Would larger bore be better?Is it really necessary to use something other than silicone tubing?

Any thoughts on wing attachement options?Removing the wing will give me access to rudder servo, receiver and battery at the nose and fuel tank at the CoG.

Think the plans say 8lbs (3.6kg), I hope to attain this- Itend to get paranoid and make things stronger than they need be. By placing fuel tank at CoG I wont add any weight in the nose. I think someone said they built one at 6lbs (2.7kg) which seems unatainable?!!?!

Thanks,

Cougar429

My Feedback: (3)

I would stay away from fuel tubing anywhere access or routing is limited. Does not have a tendency to kink when new, but it eventually starts to break down. You will also have some frustration with chafing, as the weight of the tubing will cause it to flex in flight. This is the reason I heat form the plastic tubing. If done correctly, (and to admit it seems I $(W@)^ it up just as often) there should be no restrictions. Unless you plan to go turbine, standard aquarium tubing should be able to feed any and all your requirements here. It also is the correct diameter for fuel tubing to fit on tightly.

p.s. Even with the use of a pump, don't forget the vent line. It should realistically be at the same height as the carb, but the pump will overcome most installation differences. The other point i've found is muffler pressure pulses are not consistent enough for pump operation. Love some of my motors having the boss in the rear cover to install the fitting out of the muffler, but otherwise I have to CAREFULLY drill and tap the cover.

Goldenduff

Hi Cougar, thanks for the support. The perry pump will be pressurised via a connection to the engine's backplate. I haven't received it yet so i am unsure if the tank will be presurised or not but I think your concern relates to operating the perry pump via the muffler?

I am thinking of ordering in some carbon fiber for the spars instead of using spruce. What CF spar thickness do you think would suffice, (rod or tube)?(one just infront of the ailerons and another before the strakes start?) The wings will be foam with high tensile tape to keep fuel off and add strength.

Cheers

Cougar429

My Feedback: (3)

If you are using the Perry pump there is no need to pressurize the tank and your pulse connection to the back cover is the norm.

I bought some C/F tubes, (stronger and lighter than rods) at the Toledo show with the intention of using them for spars as you mentioned. Unfortunately I already had the wing framed out. I have 1/2" for the main spar and 1/4" for the rear. The way to do it is to line all the wing ribs together, orienting the rears together and front centerlines, then drilling through for perfect alignment.

My placement for the front spar was straight across at the rear of the stock landing gear notch. It was not to extend to the last few ribs as the stock spars were still to be included.