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Old Feb 04, 2012, 01:43 PM
60 years of RC flying
Daedalus66's Avatar
Canada, ON, Ottawa
Joined Feb 2006
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Originally Posted by Wormboy View Post
Cheers for the advice, CG , expo and throws are as per scratchbuild manual dual rates are at 50% of full rates.

I've run afoul of reversed servos on previous planes so they are always on my post build as well as preflight checks

I did have a servo issue this afternoon. I stupidly didnt fire up the servos to find centre before I glued the horizontal stab on. Of course when I did power up, it was so far off centre the arm was pointing directly aft instead of off to the side. Imagine my surprise when Down stick = down elevator and Up stick = down elevator . Ended up pulling off the nacelle top again and recentering the servo arm. Derp.

How do you find the duct tape holds up to the water? I'd have thought it would peel off fairly quickly.
I would suggest setting elevator to about 70% for low rate or you may not have enough for good control. I got caught that way and didn't have enough to get me out of trouble. The real problems with control sensitivity are more with aileron than elevator, so extra elevator is easier to manage.

I've done the servo centering thing too, though not on a Polaris, so access was not so difficult.


I've used several types of duct tape on the bottom and only once had some peel off. That was because I peeled it back and restuck it. I now use fresh tape (I had a hatch in the rear bottom for servo access. It was fine till I opened it at the lake and realized I didn't have tape with me. On the next flight the whole hatch came off during a touch and go. I wondered why the trim changed and the model was slow to take off! No harm done.)

My favorite tape is Scotch Tough Transparent, but I've also used stuff from the Dollar store. Gorilla Tape is too heavy. Duck Tape is good and comes in a nice fluorescent orange.

By the way, duct tape was originally used in WW2 to seal water out of ammunition boxes and the like. It got the name of duck tape because it shed water. In was only after the war that the name was changed. In fact, it is not approved for ductwork.
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Old Feb 04, 2012, 01:53 PM
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Joined Oct 2009
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Originally Posted by Daedalus66 View Post
I would suggest setting elevator to about 70% for low rate or you may not have enough for good control. I got caught that way and didn't have enough to get me out of trouble. The real problems with control sensitivity are more with aileron than elevator, so extra elevator is easier to manage.

I've done the servo centering thing too, though not on a Polaris, so access was not so difficult.


I've used several types of duct tape on the bottom and only once had some peel off. That was because I peeled it back and restuck it. I now use fresh tape (I had a hatch in the rear bottom for servo access. It was fine till I opened it at the lake and realized I didn't have tape with me. On the next flight the whole hatch came off during a touch and go. I wondered why the trim changed and the model was slow to take off! No harm done.)

My favorite tape is Scotch Tough Transparent, but I've also used stuff from the Dollar store. Gorilla Tape is too heavy. Duck Tape is good and comes in a nice fluorescent orange.

By the way, duct tape was originally used in WW2 to seal water out of ammunition boxes and the like. It got the name of duck tape because it shed water. In was only after the war that the name was changed. In fact, it is not approved for ductwork.
Yep you want to get the high Temp osha approved tape for duct taping.
I find the bright chrome colored duct tape is best for flue pipes..on Water heaters,Garage furnaces,,and the like..
A bit pricy thought...
It works well over the wife's mouth when I'am reading a good book our watching a good movie,,??
Later,
Lenny
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Old Feb 04, 2012, 02:05 PM
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United Kingdom, England, Lincoln
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Originally Posted by nickchud View Post
Hello Alex

I've used lots of UHU Por. It's the one I like best, mainly because it's not so brittle as the CA. I spread it on one side of the joint, push the two sides together and smear them about a bit, then take them apart and wait 3 mins. It works fine, even for a destructive flyer like me. I use epoxy for motor mounts or landing gear if required.

I think I took 2 or 3 evenings for my mini Polaris. Don't waste a moment - you'll love it in the snow!

Nick
Hi Nick,

Thanks for the advice.
I tried it on more scrap pieces of depron and got better results, however, I was still able to pull the two pieces apart fairly easily. Maybe I was using too much UHU Por, or maybe not enough

Anyway, I will practice some more to get it right.

Alex.
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Old Feb 04, 2012, 02:37 PM
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Crewe England
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Originally Posted by abroadhurst94 View Post
Hi Nick,

Thanks for the advice.
I tried it on more scrap pieces of depron and got better results, however, I was still able to pull the two pieces apart fairly easily. Maybe I was using too much UHU Por, or maybe not enough

Anyway, I will practice some more to get it right.

Alex.
Nick will probably agree with me that the chances are you are using to much UHU. The surfaces to be joined both only need to have a very thin smear obtained by sliding the parts together when the Uhu is first applied to one surface. Then separate the two parts straight away and wait at least three minutes. Infact I have made a cup of tea and drunk it before finally making the joint! The surfaces should appear to be completely dry before bringing them finally together DO NOT touch these surfaces however or you will contaminate the UHU film. Make sure you have the joint aligned accurately because once the two halves meet with the smallest of pressure, you will not easily be able to separate them for a second chance, the joint will be that strong.
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Old Feb 04, 2012, 03:13 PM
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United Kingdom, England, Lincoln
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Originally Posted by acecall View Post
Nick will probably agree with me that the chances are you are using to much UHU. The surfaces to be joined both only need to have a very thin smear obtained by sliding the parts together when the Uhu is first applied to one surface. Then separate the two parts straight away and wait at least three minutes. Infact I have made a cup of tea and drunk it before finally making the joint! The surfaces should appear to be completely dry before bringing them finally together DO NOT touch these surfaces however or you will contaminate the UHU film. Make sure you have the joint aligned accurately because once the two halves meet with the smallest of pressure, you will not easily be able to separate them for a second chance, the joint will be that strong.
Thanks Acecall, I'll try that now and see what happens.
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Old Feb 04, 2012, 04:34 PM
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Canberra Australia
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With UHU POR I would suggest 10 minutes is the minimum you should wait before bringing the two pieces together. This gives an instant high strength bond, but you need to wait an hour or so before really stressing the joint.

UHU POR is an excellent glue. Even if you leave the glue for hours before joining it will still give a perfect bond. On the Alfa MiG21 UHU POR is applied on the two tailplanes during manufacture - this provides a strong bond when the model is finally assembled by the owner even though it could be months later before the join is finally made.
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Old Feb 04, 2012, 05:21 PM
Aussie, Aussie, Aussie!
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Australia, NT, Katherine
Joined Apr 2009
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Originally Posted by ggcrandall1 View Post
Instead of making the floats wider have you thought about making them deeper? Maybe just a bit deeper at the trailing edge? (Trailing end lower into the water.)

I couldn't tell much about your vectored thrust from just one viewing. I'll go back and watch it again. What is your feeling about it? Worth the effort? Do you have the thrust vectoring tied into the elevator control? Separate servo I presume.

I really like the transportation feature. Nice to be able be able to transport is a smaller space. Additional room for more airplanes. Can you post details of the construction?

Glen
Hi Glen,

I guess I should explain why I am playing with the wingtip floats in the first place.

There is one recurring issue encountered by most on this thread regarding 'flip-overs'. Aus and I have noted that just before a 'flip-over' occurs the downwind wing submerges. Once this wing submerges its game-over! The submerged wing acts as an anchor assisting the wind in accomplishing a 'flip-over'.

I mistakenly thought I could just increase wingtip buoyancy to reduce the wingtip from submerging, but this introduced more tip drag and the interesting take-off behavior. To try and maintain the increased buoyancy but bring back the drag to what the normal floats had, I am going to 'shape' the larger floats like a boat hull.

It will be worth the effort if it lessens the susceptibility to 'flip-overs' in moderate wind conditions. I think we all know the solution when it comes to high winds.

The vectored thrust? Well I was worried I would over control Vectaris in pitch on the test flight because it has vectored thrust and an all-moving stabilator. To answer one of your questions the entire Nacelle and Stabilator move as one, so there is no way to separate them. Hence there is only an elevator servo which moves the Nacelle.

The Nacelle moves +/-5degs either side of the original -2deg thrust line. For the test flight I had three flight modes set as sensitivity was an unknown. Flight mode 0 (FM0) was setup to give me full travel with 50% Expo, FM1 was setup to give me full travel with 25% Expo and FM2 was setup to give me full travel with 15% Expo.

I soon realised after take-off that I needed to move the stick back a lot further than I normally do to get her to rotate, so I switched to FM1 on the climbing turn. Required a little trim in pitch which is interesting because it was perfectly balanced on the step and the Nacelle neutral was set to -2degs using my iPhone. Once I have flown her more than the 6 packs so far, I will be interested to re-measure the Nacelle thrust line.

Is it worth it? Well I need to do some more flights before I can qualitatively answer that question. Preliminary feelings is yes, but the prototype is heavier than I like my Polarii (Vectarii) to be, so performance could be even better once I build it with care. My 100% Polaris is 650g and uses a 1300mAh pack, 100% Vectaris is 760g and has to use my 1850mAh packs to get it to balance. The tail is heavier than it should be due to the materials I used, but I can easily maintain the strength and make it lighter in future builds.

Transportability? Yes I need to add Vectaris to my blog anyway, so rather than clutter up the Polaris thread I will detail how I did this there as well as the vectored tail. I took many photos during construction so explaining myself should be easy enough. The transportability feature is a proof of concept and is intended more for the 133% sizes but as you can see it is do-able on the 100%.

Think I'll get started on the blog today.

Cheers
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Old Feb 04, 2012, 05:22 PM
60 years of RC flying
Daedalus66's Avatar
Canada, ON, Ottawa
Joined Feb 2006
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Quote:
Originally Posted by CaseySP View Post
With UHU POR I would suggest 10 minutes is the minimum you should wait before bringing the two pieces together. This gives an instant high strength bond, but you need to wait an hour or so before really stressing the joint.

UHU POR is an excellent glue. Even if you leave the glue for hours before joining it will still give a perfect bond. On the Alfa MiG21 UHU POR is applied on the two tailplanes during manufacture - this provides a strong bond when the model is finally assembled by the owner even though it could be months later before the join is finally made.
Well I've learned new respect for POR. I must give it another try. Thanks, guys.
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Old Feb 04, 2012, 05:36 PM
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Originally Posted by kingsflyer View Post
NRG2GO -- Have you had a chance to try inverted flight yet? The vectored thrust may perform better inverted than the stock -2 degree stab setup. How about high alpha when you have to jab the throttle wide open? With your setup, you may not get the sever nose down jerk normally associated with pylon mounted motors.
McD
McD,

No inverted flight as yet but it's next on the test schedule. High alpha yes Vectaris has ZERO wing rock in high alpha?? This could be a factor of the changed thrust line or the enlarged wingtip floats or both, but it just tracked true with no wing rock. I had it settled into high alpha with full back stick held, aileron and rudder inputs responded well. Vectaris seemed to transition into high alpha well so I didn't do any throttle jabbing but I can test that for you next time I fly. If the wing rock starts coming back as I modify my wingtip floats I guess I'll know how much they play a part in that wing rock phenomena.

Cheers
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Old Feb 04, 2012, 05:41 PM
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Australia, NT, Katherine
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Originally Posted by Wormboy View Post
Couple of pre maiden pix.

I'm not confident that i've sealed up the hull tight enough for a water launch yet so the maiden will be off terra firma.

I do hope to fly off water so i will be sealing the hull properly, probably with WBPU and some the missus' left over silk.
Likewise the tape racing stripes will be replaced with a proper paint job.
Nice,

It's the birthing season of Polarii by the looks of it. Having a woopsy on water is a little more forgiving than on Terra Firma but if yours isn't sealed properly yet, don't risk it. Look forward to the post test flight report, video and pics.
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Old Feb 04, 2012, 06:12 PM
Tony Audsley Retired Locksmith
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Australia, WA, Perth
Joined Sep 2011
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nmrg2go, great mods mate, look forward to seeing your blog when its finished

I will be watching with interest your reports and flight tests

Lockey
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Old Feb 04, 2012, 06:20 PM
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Joined Oct 2009
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NOSE-JOB started ,,HUMMMMM

Heavy into getting her fixed up..
Any comements or suggestions please don't hesitate ??
Sized the 2 side like Dadeles mentioned with using the wing SLOT as a guide..
Made a pattern cut for the sides to Marry..
Sticks are a little over kill and will be a problem flexing the 2 sides to line up with bottom..
But should add strenght to the bottom and sides..
A mix of 2 part epoxy on the edge of the sticks and a small stream of Gorrilla
glue up the middle.
Let set over nite..
A light bead of the same and pen pokes on the edgeing for good support bond.
I made a few extra sets Just in case they are needed again,,{I hope NOT}..
ATTACHED PHOTO'S SHOW MY PROGRESS..
2 DAY WORK AND THAT WAS AT MY PACE..
SO FAR SO GOOD??
LATER,
LENNY
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Old Feb 04, 2012, 06:33 PM
60 years of RC flying
Daedalus66's Avatar
Canada, ON, Ottawa
Joined Feb 2006
16,967 Posts
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Originally Posted by nrg2go View Post
There is one recurring issue encountered by most on this thread regarding 'flip-overs'. Aus and I have noted that just before a 'flip-over' occurs the downwind wing submerges. Once this wing submerges its game-over! The submerged wing acts as an anchor assisting the wind in accomplishing a 'flip-over'.

I mistakenly thought I could just increase wingtip buoyancy to reduce the wingtip from submerging, but this introduced more tip drag and the interesting take-off behavior. To try and maintain the increased buoyancy but bring back the drag to what the normal floats had, I am going to 'shape' the larger floats like a boat hull.

It will be worth the effort if it lessens the susceptibility to 'flip-overs' in moderate wind conditions. I think we all know the solution when it comes to high winds.
I wouldn't want people to think there is a "tip over problem" with the Polaris. In three years of flying I have yet to tip the Polaris or the Mini except in a crash. It's less likely to tip than just about any other water plane I've flown (which doesn't mean it can't be tipped if the wind is strong enough).

I have managed to tip the XL about three times, always when the wind was quite strong. Adding a couple of extra laminations to the tip floats did make it a bit more resistant to tipping, but in the end I became convinced that the issue was really that the XL has a very high fin, which gives the wind a lot of leverage.

The answer, I think, is to reduce the size of the top fin. I know the model flies fine without it, perhaps losing just a bit of directional stability. So I will have a removable top fin for windy weather flying.

Perhaps an even better idea would be Lockey-style twin booms with no top fin.


I am convinced that no practical enlargement of the tip floats will help much. As I explained earlier, they can't be made deeper if the model is to get off cleanly, and even making them wider seems to have adverse consequences.
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Old Feb 04, 2012, 07:45 PM
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Originally Posted by Daedalus66 View Post
The Vectoris looks great and flies well. I'd like to see more detail of the removable wing panels and how the ailerons work. I had thought about eliminating ailerons and using "ailevators". That is, all moving stab halves that work like elevons, but my experiments on another model showed poor roll control. So I think the ailerons are needed with a mechanical linkage.

The problem with vectored thrust on the Polaris is that the prop is very close to the CG, so there's not much moment arm for the up or down thrust to work with. The further back you can get the prop the better, which argues for shortening the nacelle as much as possible. Of course, the ideal would be a pusher setup, but it's a bit hard to see how that would work.

You don't want to increase the depth of the tip floats, as doing so would limit the takeoff angle and thus prolong the takeoff run. The way to shorten the takeoff with nearly any water plane is to increase the angle of rotation, either by increasing the depth of the fuselage at the step or by cutting away the rear of the fuselage/floats to allow the model to rotate more.

By the way, what does Vectoris weigh?
Hi D66,

I think I already answered in others questions, but I will share how I did it for those that are interested in my blog shortly. I guess for those that have an aversion to torque tubes, you ain't going to like the how.

I agree the more aft the prop the better the reaction out of vectoring. Shortening the Nacelle won't be possible in the current configuration because the prop will strike the leading edge of the vertical fin near the base. Placing it on the rear is a great transformation on Vectaris and I believe easily done once you see how I did the current version, excellent idea D66.

Edit: Having thought a little more about this I don't think I will peruse it because the stabilator and rudder will no longer have prop wash over them.

Sorry, I wasn't trying to suggest the Polaris has a tipping problem. You are most correct that compared to other types of float planes where the centre of mass is way above the water line, the Polaris is like a Formula1 car compared to an SUV. Even so, lots of individuals seem to still want to fly in less than ideal wind conditions and if a combination of modifications lessens the tendency to flip-over then I want it. I'm one of those individuals that doesn't know when to hangar their aircraft.

The materials I used in the prototype Vectaris was a little on the heavy side which overall made it heavier in the tail than it should be, but still at 760g it's not too bad for a prototype.

Cheers
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Old Feb 04, 2012, 09:43 PM
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Australia, WA, Madeley
Joined Jul 2011
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Originally Posted by Daedalus66 View Post
I would suggest setting elevator to about 70% for low rate or you may not have enough for good control.

My favorite tape is Scotch Tough Transparent, but I've also used stuff from the Dollar store. Gorilla Tape is too heavy. Duck Tape is good and comes in a nice fluorescent orange.

By the way, duct tape was originally used in WW2 to seal water out of ammunition boxes and the like. It got the name of duck tape because it shed water. In was only after the war that the name was changed. In fact, it is not approved for ductwork.
Thanks, d/r changed as per suggestions

Transparent scotch tape should do the trick for me then. That's what I already use for hinges on most of my depron builds so there is plenty lying around. The red striping is "bear tape" sort of a lower quality, less sticky tape. That will be coming off in favor of acrylic paint.

Always wondered why it was called duck tape. Cool story

Vectaris looks awesome NRG. Top job on the mods
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