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Old May 29, 2012, 01:24 AM
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Han2007,
Elevator extension or not, that's going to fly just fine. Just get the CG right and you're good to go. Great looking Polaris!
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Old May 29, 2012, 02:06 AM
Aussie, Aussie, Aussie!
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Melbourne, Australia
Joined Apr 2009
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Originally Posted by Han2007 View Post
I really want to thank everyone for there help and advice, especially nrg2go, D66, and Scott. Going on your advice using the 2212-6/40amp-ESC/and 2200mAh batteries I nixed the vents and just went with the heat sink. Plus I just saw a video on youtube where a Polaris gets dunked on landing and figure an absence of vents would really be a plus.

Also, D66 once warned me not to over think this build but I guess my OCD is really flaring up. With all the recent talk regarding the negative incidence angle on the elevator/engine nacelle it got me wondering. The underside of my nacelle is set at zero plane to the wing (to help disguise the negative incidence) with the motor and the top of the nacelle/elevator set at the -2 degree down angle. With the underside of the nacelle being as wide as it is I figured it would act as a control surface so I widened the elevator by an inch for more control. My question is will this be enough? Or am I just over thinking this again and don't sweat it.
I said it before and I'll say it again..... That's one awesome looking Polaris, especially the wide body Nacelle.

As long as your motor mount is not 90degs to the bottom of the Nacelle (meaning the thrust line should be at -2degs), I really don't think the underside of the Nacelle will matter too much.

You simply must have a dedicated photographer on the day, no two! Another one on a video camera as well. What I'd really like to see is the good old reflection photo taken just above the water with this beauty. Can't wait.
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Old May 29, 2012, 04:39 AM
Tony Audsley Retired Locksmith
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Australia, WA, Perth
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Niiiiiice looking Polaris Han2007, love the widened nacelle

Lockey
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Old May 29, 2012, 06:53 AM
59 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Originally Posted by Han2007 View Post
With the underside of the nacelle being as wide as it is I figured it would act as a control surface so I widened the elevator by an inch for more control. My question is will this be enough? Or am I just over thinking this again and don't sweat it.
Yes, you're over thinking! In fact, your potential problem is just the opposite. With a whole lot of extra elevator, you will have to be careful setting up the controls so you don't get excessive sensitivity. There are probably more Polaris crashes caused by over sensitivity and the resulting over control than any other issue.

All you need to do, though, is to set up the elevator on low rate so it has about 1/2" throw each way. That should be ample for good control and will give you a chance to find out how much throw is needed for the kind of flying you want to do.

With the change in size and angles, you may find that the model needs a bit of elevator trim to fly level, so be ready for this on your first flight.

Be careful to set up the ailerons with moderate throw. About 1/2" is plenty for low rate. Use 30% or so expo on A and E.

Rudder is not critical, so use an inch or so, but it helps to have expo to reduce sensitivity around neutral for steering during takeoff.

Make sure the CG is on the step or no more than about 1/4" ahead.

It's a very nice looking model, so be careful till you have things sorted out. Best of luck. We're expecting flight pictures.
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Old May 29, 2012, 11:55 AM
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The Netherlands
Joined Oct 2008
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Originally Posted by ak68 View Post
Nice flying deadalus! Nice pond too. Especially for RC I understand?

Video: when the sun goes down: uncut
How boring
AK68

Mavlo77: You are invited: "het gat" (name of the location)
Cool video AK68! Nice landings too.
Yes I wish to fly together with you in "het gat" (good that we don't need to translate that...).
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Old May 29, 2012, 01:33 PM
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I am getting ready to build the Polaris XL and ran into a glitch. I had the file "Polaris Parts Templates (Scaled 133 Tiled).pdf" printed at an office supply store but when I started to measure the parts I found that they were the same size as the standard Polaris. i.e. 29" wing span and 4" fuselage width. The 4" scale pattern measures 4" so I am puzzled. Has anyone else had this problem or have solution?

PS - This file printed on 2 pieces of 34" wide paper. Is there a truly "tiled" drawing that I can print on 81/2 x 11 paper at home on my printer like the original? Those large format prints cost almost $14.
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Old May 29, 2012, 02:36 PM
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Nevada City CA
Joined Nov 2001
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Originally Posted by Ramblin View Post
I am getting ready to build the Polaris XL and ran into a glitch. I had the file "Polaris Parts Templates (Scaled 133 Tiled).pdf" printed at an office supply store but when I started to measure the parts I found that they were the same size as the standard Polaris. i.e. 29" wing span and 4" fuselage width. The 4" scale pattern measures 4" so I am puzzled. Has anyone else had this problem or have solution?

PS - This file printed on 2 pieces of 34" wide paper. Is there a truly "tiled" drawing that I can print on 81/2 x 11 paper at home on my printer like the original? Those large format prints cost almost $14.
Yep, the PDF "Tiled" version will give you a 133% sized plans, that are too big for even large format printers to put out, or will not print out correctly. Spent $11 finding this out too...
As you begin to print, there is a choice of scale and "tiled", I used the "tiled" option. I printed it out on my home printer, 48 pages! in all I believe, which gives you two plan sheets, taped it all together and cut out my parts. Took some time but if you like puzzles, it can be some fun.
One interesting "problem" was that the left and right fuselage sides are different sizes! I found that one side was about 1/2" to 5/8" taller at the step than the other. Maybe it was my printer, but the side lengths were correct...so I used the larger fuselage side and made two foam sides from it...
Like others have commented, the plans appear to have been purely "scaled up" so that the thickness of the depron is closer to 8mm rather than the standard 5-6mm, so some adjustments must be made. Same with the height of the motor pylon and placement of the "second" CF wing spar. Once printed, I adjusted the foam slot thickness for the wing, added the second spar about 4 1/4" forward of the main spar, made sure that I had at least 4 1/4" prop clearance on the pylon motor mount. Looks like my pylon is a bit big at 2 1/2" square, as I cut the pylon too short and added to the top of the pylon to get the motor firewall up high enough for a 8" prop but fits in with the rest of the larger model. Took a little planning but that is the best part of scratch building, IMHO.
My XL is ready for maiden flight, just needs the prop and a little more trim tape for color. So far, AUW without battery is 29 oz. Seems in step with other builds, as I added a little 'glass and enamel paint to the bottom and pylon, with somewhat larger CF wing rods (all that I had available) and a 80 gm HET 1500 kV motor (older brushless). So I may be in the ballpark...got to try to read the older posts again.
Pictures added. Big Sucker...compared to the 100%.
TK
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Old May 29, 2012, 03:02 PM
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Originally Posted by sam2000pres View Post
Yep, the PDF "Tiled" version will give you a 133% sized plans, that are too big for even large format printers to put out, or will not print out correctly. Spent $11 finding this out too...
Thanks for the info. I have read every post of this forum and do not recall ever reading about this problem.
Also you mentioned a second wing spar.Is this necessary for normal flying or just for high speed aerobatics?
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Old May 29, 2012, 03:40 PM
59 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Originally Posted by Ramblin View Post
Thanks for the info. I have read every post of this forum and do not recall ever reading about this problem.
Also you mentioned a second wing spar.Is this necessary for normal flying or just for high speed aerobatics?
It has been discussed before (e.g. post #13988). The scaled up plan is just that and must be adjusted to allow for the thickness of material. The XL is a distinct design with, for example, a proportionately lower nacelle limited to an 8" prop, whereas the scaled up version can take 10". The XL should be slightly superior in handling, but I doubt you'd notice.

The XL/133 doesn't do high speed aerobatics (though it definitely does do aerobatics!). It's distinctly slower than the 100% Polaris (about 10 mph). While I haven't tried it without the second spar, I strongly recommend that you include one, as the wing is quite flexible. I've never had any problems in over a year of flying, but I do have pictures showing considerable bending of the wing during serious pull-outs, and that's with two spars.
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Old May 29, 2012, 03:53 PM
59 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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How to launch a Polaris

We had the initial trial of a new launch device at our club pond today. The pictures tell it all.
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Old May 29, 2012, 04:00 PM
59 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Originally Posted by sam2000pres View Post
My XL is ready for maiden flight, just needs the prop and a little more trim tape for color. So far, AUW without battery is 29 oz. Seems in step with other builds, as I added a little 'glass and enamel paint to the bottom and pylon, with somewhat larger CF wing rods (all that I had available) and a 80 gm HET 1500 kV motor (older brushless). So I may be in the ballpark...got to try to read the older posts again.
Pictures to follow. Big Sucker...compared to the 100%.
TK
Anywhere in the mid-30 oz range is fine for weight, and mine was still OK at 39oz when I tried it with two 2200 batteries in parallel. That motor sounds about like the standard 2810-9 in terms of KV and size. I'm sure it will do the job. You may need to experiment a bit to find the ideal prop. An 8x6 APC would be a good starting point and you might find you want to go to an 8x6 three-blader for maximum performance. But keep an eye on current.
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Old May 29, 2012, 04:33 PM
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Nevada City CA
Joined Nov 2001
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Polaris XL

Ramblin,
Ditto what Daedalus66 wrote...
My XL Polaris wing (2 CF spars) is more flexible under loads than the smaller 100% Polaris (1 CF Spar). That extra 10" of span needs the second CF wng spar or there will be trouble...
I fly an old Tribute 3D 40" flat foamie that has twin CF wing spars, that really bow nicely under load. It has a speed limit due to the tail feathers not liking that much wind, as the fuselage is also more flexible than the new style 3D foamies. Have not failed it with many overspeed, panic pullouts so far...

Daedalus66, you mentioned the APC 8x6 as a good starting point for this motor, and I agree. The motor flew an old Alliance pattern foamie using a 9x6 APC, 2200 3S pack and a Phoenix 35, pulling about 25-28 A. This combo flew for years before I retired the airframe. I also agree that the 8x6 3-blade would be excellent, if I can find one locally. These new 25C and 30C lipos are the ticket for great performance. I got used to 6 min. flights with the 100% on 1600 mah lipos, got a little warm with the 2200kV motor but sure is entertaining. Looking forward to some more relaxing flights with the XL.
TK
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Old May 29, 2012, 04:35 PM
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Melbourne, Australia
Joined Apr 2009
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Originally Posted by Daedalus66 View Post
We had the initial trial of a new launch device at our club pond today. The pictures tell it all.
I was expecting a catapult launching device that would have the model flying in less than a second. Don't build us up like that, but clever.
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Old May 29, 2012, 05:04 PM
59 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Originally Posted by sam2000pres View Post
Daedalus66, you mentioned the APC 8x6 as a good starting point for this motor, and I agree. The motor flew an old Alliance pattern foamie using a 9x6 APC, 2200 3S pack and a Phoenix 35, pulling about 25-28 A. This combo flew for years before I retired the airframe. I also agree that the 8x6 3-blade would be excellent, if I can find one locally. These new 25C and 30C lipos are the ticket for great performance. I got used to 6 min. flights with the 100% on 1600 mah lipos, got a little warm with the 2200kV motor but sure is entertaining. Looking forward to some more relaxing flights with the XL.
TK
I would just add that you really do need to measure current to get a sense of how much a given prop is drawing and stay within motor limits. If you measure static current (with a watt meter or similar) you can knock off 2-3A to allow for unloading in the air. I used an Eagletree logger and the effect was very clear.
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Old May 29, 2012, 06:23 PM
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Originally Posted by sam2000pres View Post
Ramblin,
Ditto what Daedalus66 wrote...
My XL Polaris wing (2 CF spars) is more flexible under loads than the smaller 100% Polaris (1 CF Spar). That extra 10" of span needs the second CF wng spar or there will be trouble...
Thanks to both of you for pointing me away from that trouble.
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