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Old Jul 14, 2011, 09:14 PM
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Cheyenne, WY
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Got to fly my Polaris some today. All I have to say is WOW what a fun plane.
Video sorry about the quality

Polaris wring out (3 min 22 sec)
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Old Jul 14, 2011, 10:52 PM
Slipping the Surly Bonds
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Attica, MI
Joined Dec 2006
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83% Polaris Maidened

I was able to get the 83%er to a maidenable state this evening. Did'nt know I was even going to do that much. All I have to say is Wow! what a nice smooth flying plane. No wonder it is such a popular model. I really like how it grooves, and the smooth takeoffs and landings. Great big Kudos to Mr. Steve Shumate on a fantastic design.

At this point the model weighs 8.3 oz without the battery. First flight was with a 1000 mAh 20C 2s battery, so the flying weight was right around 10.3 oz. My wire adapter from the Deans Ultra plug on the ESC to a JST plug on the battery was almost melted after the flight, but I know that has really cheap wire in it. Not able to transmit the demand for power.

Got to pretty up the joints and gussie it up with some colored packing tape. Even if its covered entirely with tape, the additional weight will be one ounce or less.

Ken
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Old Jul 15, 2011, 02:28 PM
Wait... what?
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United States, MI, Plymouth
Joined Sep 2010
284 Posts
Very nice! What motor/prop are you running on 2s? You hit th nail on the head with jst, its not beefy enough for motor/esc current demands. Definitely want to put a deans or similar on your battery.
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Old Jul 15, 2011, 04:24 PM
Slipping the Surly Bonds
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Attica, MI
Joined Dec 2006
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Quote:
Originally Posted by aeryck View Post
Very nice! What motor/prop are you running on 2s? You hit th nail on the head with jst, its not beefy enough for motor/esc current demands. Definitely want to put a deans or similar on your battery.
Thanks!

Motor is a 3000 Kv HXT 2730 (Blue Wonder) with an APC 5.1 x 4.5 prop.

Ken
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Old Jul 15, 2011, 08:17 PM
unconventional :-)
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Brisbane north, Australia
Joined Feb 2009
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I am thinking of an alternative way to mount the motor and servo doubler. At the hardware shops there are thin, self adhesive aluminum signs and the glue bonds very strongly. I am thinking of shaping these components from the sign material rather than ply. I prefer the way these little screws work in aluminum rather than wood for some reason. I think it would be quite neat.

I would do the vstab stiffener as well but I think the bond between the vstab and the ply is structurally important.

Anyone tried it or have advice?

PS I wonder what glue they use. You just peel off the wax paper and press the signs on, and it is a very strong bond.
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Old Jul 16, 2011, 05:09 PM
60 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Quote:
Originally Posted by dz1sfb View Post
I was able to get the 83%er to a maidenable state this evening. Did'nt know I was even going to do that much. All I have to say is Wow! what a nice smooth flying plane. No wonder it is such a popular model. I really like how it grooves, and the smooth takeoffs and landings. Great big Kudos to Mr. Steve Shumate on a fantastic design.

At this point the model weighs 8.3 oz without the battery. First flight was with a 1000 mAh 20C 2s battery, so the flying weight was right around 10.3 oz. My wire adapter from the Deans Ultra plug on the ESC to a JST plug on the battery was almost melted after the flight, but I know that has really cheap wire in it. Not able to transmit the demand for power.

Ken
Glad to hear of your success. I'm not surprised you get nice performance with a 10-11oz 83%. That's about like a 16oz 100%. Should be a real floater.

Judging from my experience with the 75% I would guess that you are using around 70 watts with the 83%. With a 2s battery, that translates into about 9A, which is an awful lot for the JST connectors. I've used them for up to about 7A, but above that would use the Deans Mini (or is it micro?). You don't need the Ultra.
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Old Jul 16, 2011, 08:44 PM
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Tualatin, OR
Joined Oct 2009
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Quote:
Originally Posted by dz1sfb View Post
Hi Gary,
What gauge wire did you use for the motor extensions?

Ken
Ken,

I don't remember exactly what the gauge of the wire extensions I used was, I think it was the same gauge as what was on the motor, though, so probably about 16g.

Gary
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Old Jul 16, 2011, 08:53 PM
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Tualatin, OR
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Quote:
Originally Posted by dz1sfb View Post
Thanks!
My wire adapter from the Deans Ultra plug on the ESC to a JST plug on the battery was almost melted after the flight, but I know that has really cheap wire in it. Not able to transmit the demand for power.

Motor is a 3000 Kv HXT 2730 (Blue Wonder) with an APC 5.1 x 4.5 prop.

Ken
Ken,

I'm using plain old JSTs on mine with the same motor. I generally run an 800mAh 2s battery. I haven't had issues with the wires or connector getting hot. I don't have the extra adapter you are using, though, so I wonder if more connectors is causing a little loss of efficiency and more heating.

I'm also using a GWS5030 prop, which will probably pull a bit less current, might be the difference.

Glad to see you got it flying. It is a fun one.

Gary
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Old Jul 16, 2011, 09:54 PM
60 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Aquacat

Here's what I've been up to for the past week: flying the Aquacat at a cottage on a lake. It was an ideal location, except that it faced east, so the sun was a problem in the morning.

Aquacat is a terrific model that makes a very nice alternative to the Polaris. It uses the same motor and has a Polaris hull, vertical tail and nacelle, but swept wing and twin boom tail. It's better for the classic aerobatic maneuvers that involve looping and rolling but not as agile as the Polaris in low speed flight. On one landing you can see a bit of wing rock as the model does a slower than usual approach and flare. But it's a most enjoyable model to fly. It's a ModelAero kit.

I also had along the Polaris Mini but only got one flight before the ESC gave out (it didn't fail completely but wouldn't generate enough power for takeoff -- I tried a substitute motor with exactly the same results).

Aquacat at the Lake (2 min 7 sec)
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Old Jul 16, 2011, 10:12 PM
Slipping the Surly Bonds
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Attica, MI
Joined Dec 2006
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Nice flying D66!

I have had good success with the JSTs for up to 10A, but I never run them at that continuosly. I am running a 15A ESC. Bench testing showed that I could pull that much on 2s. I put the Deans Ultra connector on because I will use this ESC elsewhere in the future, maybe. Did a direct solder up on the motor wires though with 16 ga. silicone insulated wire. Made up a new adapter to get to the JST on my batteries. Very short and high quality wire. The heating issue is gone.

I would like to try a smaller diameter prop first. I like the pitch speed I am running now. It has enough ummph to get off the water on 2s. Also got some forward and rearward facing video from the plane to process and show. I was flying from my yard.

More to come,
Ken
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Old Jul 16, 2011, 11:21 PM
Slipping the Surly Bonds
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Attica, MI
Joined Dec 2006
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Did a quick amp test this evening. Running the 3000 Kv BW motor on 2s, with a 5 x 4.3 GWS prop reduced amps drawn to 10. That seems like a more reasonable load on 1000 mAh batteries for some duration and less getting warm.

I let this combo run WOT for a rew minutes and the battery wire and connector were getting quite warm. I suspect the connector was warming the wires.

Ken
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Old Jul 17, 2011, 02:24 AM
unconventional :-)
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Brisbane north, Australia
Joined Feb 2009
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Can extreme aileron put you into a spin?

Just used 4 batteries, last battery was a smaller one and was way too far back, had to adjust the trim 3 or 4 clicks. It was flying ok so I started doing loops and rolls at full throttle. Loops....good, roll right....... good, roll left and

It was just spinning and twirling in the one spot. Center sticks and full throttle..... just kept spinning. I thought I snapped a wing spar.

Cut the throttle and let it fall some, stopped spinning and plopped down in the water, right way up. What a relief.

Taxi'd home, no damage but a cracked battery tray and battery sitting down 20mm from where it should be. The battery tray foam was this soft batch of depron that is weak and flexible.

So did my battery tray snap during the roll and mess up my CG in the roll, or snap during the splash down?

Was it a true spin because of my CG so far back and my extreme deflections with no expo on this model?

Just my luck today, when I put the model down in the garage, I snapped the left wing tip off. A little glue and this old battered model will be flying again.
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Old Jul 17, 2011, 08:18 AM
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United States, TX, Kingsland
Joined Sep 2005
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Quote:
Originally Posted by kadil View Post
It was just spinning and twirling in the one spot. Center sticks and full throttle..... just kept spinning.
Was it a true spin because of my CG so far back and my extreme deflections with no expo on this model?
Sounds like you got it into a flat spin. Flat spins can have high rotational speeds, but not very high rates of descent. Flat spins are hard to get out of when your CG is shifted too far back. You did the right thing by neutralizing your controls, because large surface deflections only keep the plane "stalled" in a flat spin.

I've had planes that would not come out of flat spins and have gone all the way down to the ground. Most have suffered very little damage due to the low vertical speed of the "landing" and several have just needed to have the pilot's drawers dusted off, the CG shifted forward a little, and they were flying again.

McD
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Old Jul 17, 2011, 08:26 AM
60 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Quote:
Originally Posted by kadil View Post
It was just spinning and twirling in the one spot. Center sticks and full throttle..... just kept spinning. I thought I snapped a wing spar.

Cut the throttle and let it fall some, stopped spinning and plopped down in the water, right way up. What a relief.

Was it a true spin because of my CG so far back and my extreme deflections with no expo on this model?
I think it was almost certainly a result of the CG being far back. The large control deflections (mainly elevator) then forced the model into a true spin condition, where one wing is fully stalled but the other is still lifting.

When I experimented with spinning a Polaris I got all sorts of weird behavior if I shifted the CG back enough. Unlike most traditionally configured models, the Polaris with its delta wing typically doesn't go into a consistent spin. With CG far back it may flop around, spin for half a turn or a turn then stop, reverse direction of rotation, etc. I had a couple of episodes which sound like your experience, where the Polaris did go into a sustained flat spin from which it didn't recover with neutral controls. I was able to stop the spin with a good blast of power to get airflow over the tail, so maybe your CG was even further back than mine.

In case anyone is worried that this might be a problem in flying the Polaris, let me stress that with a normal CG (on or very slightly ahead of the step), the Polaris will only spiral dive, not do a true spin, and its recovery is immediate when controls are neutralized.
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Old Jul 17, 2011, 08:31 AM
60 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Originally Posted by kingsflyer View Post
I've had planes that would not come out of flat spins and have gone all the way down to the ground. Most have suffered very little damage due to the low vertical speed of the "landing" and several have just needed to have the pilot's drawers dusted off, the CG shifted forward a little, and they were flying again.

McD
It can also be that they need lateral area that isn't blanked in the flat spin. Many years ago I had a Debolt Jennie (shoulder wing with .35 engine) that behaved that way. The cure was a subfin under the fuselage.
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