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Jun 24, 2020, 10:43 AM
Youtube channel : solentlifeuk
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Quote:
Originally Posted by van3st
I also use seperate servos for each wing and I use them in an elevon-mix, so in the case, the elevator servo fails, I still can bring it in safe this way. It worked out well a few times. If i lose a servo it is nearly always the elvator one, but donīt ask me why.
Funny that near always its my rudder one !

My wing ones are not sealed or anything ... but they keep on working
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Jun 29, 2020, 08:00 AM
Mk9
Mk9
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When my elevator servo finally failed in a vertical dive (and I lacked the presence of mind to switch to coupled mode and use elevon), I traced it back to corrosion in the extension cable to servo plug. That's a long lead for that servo. So this time I will solder the leads, not rely on a servo connector in the bilge.
Jun 29, 2020, 09:56 AM
watch your head
Well, soldering the lead is a good idea.
I use the elevonmix permanently, so if the elevator fails i realize it by having about half authority left. So i donīt care about switching to the "rescuemode".
Jun 29, 2020, 11:00 AM
Youtube channel : solentlifeuk
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Quote:
Originally Posted by Mk9
When my elevator servo finally failed in a vertical dive (and I lacked the presence of mind to switch to coupled mode and use elevon), I traced it back to corrosion in the extension cable to servo plug. That's a long lead for that servo. So this time I will solder the leads, not rely on a servo connector in the bilge.
I don't have any wires or leads in the lower section of fuselage ... all mine are in the top section other than the aileron wires buried in channels in each wing.
Today, 06:35 AM
Mk9
Mk9
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Quote:
Originally Posted by van3st
Well, soldering the lead is a good idea.
I use the elevonmix permanently, so if the elevator fails i realize it by having about half authority left. So i donīt care about switching to the "rescuemode".
When I want coupled mode, I want massive authority (loops in 1 fuze length ) and my flying skills never quite got to grips with the finesse needed to balance that extreme authority with reliable landings - a botched spot landing attempt (belly flop) resulting in a stalled, over-flared Polaris with coupled authority, a meter above our very shallow seasonal lake is a scary thing. I was getting better at leaving the 'scary' mix in all the time, but extra throw does compound the errors.

You will get water inside the hull regularly - both top and bottom, so top and bottom aren't really that different in my view - in fact, my ex-Polaris has more corrosion on the top of the servos (mounted upright through the wing) than the bottom, and the wing mounted servos have less evidence of corrosion on the bottom than the elevator servo does! I didn't use torque rods though. That would suggest water ingress through the hatch is more likely than water ingress through control rod holes, and even the wiring feed-throughs in the bilge. I did install a very big and quite leaky hatch towards the end though. [EDIT: looking at that pic made me realise I must have smeared silicone over the base of the wing mounted servos, perhaps *THAT* was a sensible thing to do!]

Access to the back area of this plane is major surgery, so I reckon anything that makes sure you never have to go in there again is worth doing, so solder and heatshrink, and silicone around the heatshrink, will be in my rebuild. Oh, and I'm not trying to convince anyone, just state my reasons behind doing it my way so other people can make up their own minds about what suits them.
Last edited by Mk9; Today at 06:40 AM. Reason: Just noticed the silicone!
Today, 11:00 AM
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I know I've shown these before but I think worth it for anyone new to Polaris ...

To avoid having to dig into the fin to change motor / servos etc. - I have led cables external faired in with tape ...



The fin being of 3 layers ... the plans channels are not cut - so you have solid 3 layers ... with central layer a few mm shorter on front edge to create a channel for cables to sit in.

Elevator and rudder servos mounted external as well ...





Aileron servos mounted as split into wings ...





The fin is supported on an enlarged ply plate :



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