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New version is simpler but much more effective, will be reviled at later stage. Great flying day today with both, after further improvement, almost got drenched on the way back but just made it! I must have been paddling 10 knots on the way back as the dark clouds were well on the way. Both of my cams starting to show the old age after all these years of treatment, one cutting constantly off due to the batt. connections and the old Tachyon lost its focus.
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There was always considerable amount of flex in the tips of Elevator stab and after all these years of flying action it is certainly not getting better. After dramatic improvement in my "XL's" modification I have also fitted the same CF reinforcement to eliminate any give, which with the time could lead to demise. Rather safe than sorry, plus lot more precise model.
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Thread OP
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Now both models are solid as a brick and what a difference in the air. No more flexing after extra CF support of nacelle. Should last another 600 flying sessions.
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I don't have fun only by flying, I get even bigger kick by writing about it! " WARNING", only for readers.
In the "SKIPPERS" mode. Going back four years, after relocating to new seaside area with the salt water lake inlets, the first thing I got was a small water plane I spotted on the internet. "HK Skipper", little delta shape foamy easy to assemble just about ready to fly by the book, but as usual with these ARF models it's always a good idea to put more thought and time into it. The first thing I decided to modify was to cut out all premoulded control surfaces and install proper nylon hinges for long lasting and reliable operation. After initial bench tests, checking out the stock power set up I found 30A, ESC and the 6x4 plastic prop rather inefficient, so it was upgraded to 45 Amp unit with reshaped APC propeller cut down to 6 and 3/8 x 5, for best figures, while measuring current draw, wattage and RPMs, giving some 275Watts per pound, promising to be a lively model. After full assembly I have used silicon to seal off any joints to minimize any posibility of salt water getting inside. The maiden flight was done by hand launch at my local field, followed by the first exiting flight off the water. To cut the story short I have logged up to date just under six hundred, 3-5 minute most enjoyable flying sessions off the water, but I must ad, the model always took long distance and lot of elevator effort movement to lift off the glass like, calm water in light wind conditions. After dialing in some flap mix to Ailerons might have help somewhat, but hitting the little ripple or water wake was an easiest way to rotate. In the recent Summer month while flying this model just about on daily bases while going for a splash I got bit fed up with this struggle taking off in dead calm so finally decided to do something about it! While confiscating with out wife's knowladge some kitchen accessory I have cut out numerous shapes of skids and fitting it to the belly of the model to check the result. My initial trials with the higher skids were useless, creating even more drag and making model totaly out of ballance with the wing tip getting constantly submerged. After gradually cutting down the height of the skid to some 8-10mm it worked almost to perfection, and the final shape I was happy with made of some .6mm aluminium sheet was epoxied in. Just can't believe its effects, now the model rotates of any water surface with ease at even 5 meter distance, tho, I never fly it with the chop higher than some 5-6 inches. Over the years I had only couple of dramas with the model, when one of the Ail. servo got stuck mid flight, making the rest of the flight rather challenging, and other time burning another servo due to the corrosion and seacing off the tiny washer on the quick link hook up. The constant maintenance and lubrication of all moving parts is a must especially when flying it off the saltwater. All up weight of my model is only 565 grams with the 3S/1800mA/45C pack, and this is still one of the model in my fleet while using the good old 36 meg. 9ch. SPCM set up despite regular questions from some, "what is that thing sticking out of my transmitter?", well, what can you say, you don't fiddle with the things that work and at least I have a good wind sock right in front of myself. During our current hot Summer, while enjoying the water activities in this paradise and all the success with the little "Skippy", I have decided to get the larger "XL" version as an excuse for my last Birthday. Unavailable at the time as an ARF version I have ordered the basic kit, and all the extras separate. Rather good decision as the model needs some modifications for flying off the water. Same as with the smaller version all controls were upgraded with the proper nylon hinges, while noticing the Aileron moulded hinge was already partly broken out of the box. The stock Aileron hook up, on one servo, and the control push rods on the bottom of the wings had to be redesign, so I have installed two Ail. servos into the cut out cavities on the top of the wings eliminating the possibility of the salt water getting inside the fuse. Unfortunately the rudder control push rod runs very low along the fuselage, with water could easily get inside the guide tube so this will need constant attention with grease lubrication. As the model is being considerable larger than my old Skipper I have noticed some flex in the wing tips while handling the air frame, and it was a big mistake I haven't done anything about it right at the beginning. The completion of the model was simple, after installing the basic two Aileron, single Elevator and Rudder controls with redesign control horn attachments. Some knife surgery to the motor nacelle had to be done to hook up the power system, and extension was made out of plastic sheet to be able to fit in the coveling over the longer can out runner motor. I have decided to hand paint the whole frame instead of using the large and heavy decals, which would only create problems over the time. Sealing it off with the clear to give it bit of protection and smoother glide. The rudder fin was also extended downward some 50 mm for more efficient steering while taxi in water, the issue I have found with my little version years ago. My hope to use 9 or 10ch. SPCM receiver fail, even with such a low 4S voltage after thorough range tests, due to an excessive interference from the ESC or the motor. After quick swap to 2.4 while using older slightly puffed up battery packs I had avail in required capacity, I hurried full of excitement to do my first flight off the lake. Just before twilight, an ideal calm conditions my attempt to rotate ended in great disappointment after numerous runs. I have noticed the model sitting very low in the water despite of only 1150 grams, AUW, and while accelerating along, creating tremendous drag. My first thought was the use of an old battery, the clone APC prop and extension rudder fin as the reason. With the sadness, hopped on my fat bike, the model in hand and pedaling back thinking about the next step. Order for new batteries and number of propellers was placed and in the meantime the rudder fin was modified by some reduction to reduce the drag. To give it bit of initial lift, new "skid kicker" was cut out after another visit to kitchen draws, based on my little Skipper and well epoxied to the belly of the fuselage. Only few days later with the new fully charged batteries it was back to the lake with my "hat cam" rolling, and off she goes! Taking off in no time after application of full power, mainly thanks to the skid kicker modification on the belly. After all the excitement of another success I didn't take much notice of some oscillation during the level flights and pretty nasty, just momentarily out of control sequence during some basic manouevre while being up high. After three flights, happy as anything, impatiently waiting for the next day to have more fun with the new toy. To confirm the effectiveness of my belly modification I have done some test flights while using the old lipo battery and there was no issue rotating. Few weeks of more action in various conditions I did noticed the oscillation getting worse and on one occasion during clock wise "U" turn I had to use full left Ailerons to get out of the roll-over. Thinking it might be just some air turbullence up higher created by trees while standing in well wind sheltered position, the bells were ringing! Unfortunately, it was too late the same evening, when I took the "XL" for another quick flying session while going for my regular evening swim. Just on the verge of twilight after enjoyable 4 minute flight I thought I give it few more touch and goes as the conditions couldn't be any nicer for flying. After rotation while in gentle climbing large "U" turn on full power the model decided to use its own mind and just kept on flipping over, nose diving at shallow angle into the mangroves across the lake some 130 meters in front of me with the sound of broken branches. I have tried my best to recover but at such a low altitude I had no hope. "She is gone", was my words to few campers observing and enjoying my flying action. After being offered a kayak to get across, I firstly had to rush on my fat bike to fetch gum booth. Lightening fast, I was back and paddling across trying to beat the darkening sky as the sun was well over the horizon. Being a low tide, I have struggled to walk across some mud to reach the edge of the mangroves, and seeing almost an impossible task to penetrate through the thick growth. Being topless with shorts and gum booth only attire made the task even more fun! To this date I still wonder how I managed to get through the first 20-25 meters of this jungle because trully, seeing it, every normal person would just give up! As I have never considered to be a normal, after few scratches trying to snake in along the thick shrub I came to slightly thinner clearing, what looked like only few inches shallow pond with the solid sand base, some 3x20 meters long. My first step into it, to cross it over, off I went!, up to my waste in "quick mud", struggling to get out of it I was stinking and black all over! Immediately after, while trying to find the easiest way to get back, the model was the last thing on my mind. Only few meters further ahead, there was a flash of something white on the dark ground and there it was, the canopy with the top hatch, and the model some 2.5 meters jammed up in the thick mangroves with the both receiver lights still fully iluminated red. Miracles sometimes happen, carefully removing the model down I have noticed only lot of scratches and few small chunks of foam missing but nothing what I would call a structural damage at this point. Unhooking the battery well secured on layer of velcro, my main issue was how to get it back through the thick growth with out any more damage. I had only some 10 minutes of twilight left so back to work creating narrow corridor path in the direction of what ever glare of reminding light there was. It took me good 20 minutes and lot of bloody scratches on my naked upper torso, but could hear a great applause from the other side of the lake after emerging with the muddy trophy in my hands. What a shame I didn't have a camera to get a pic of myself, I must have looked hilarious. Probably worse than "Sh-watzy meeting Predator". OH, what a pleasure to wash it all down in the lake afterwards. Thanking to my kayak helpers I was back on my bike in total darkness with "XL" under my arm. While trying to explain in brief what happen to my impatient wife waiting with the hot dinner, her reply was, " good, at least you won't pest me, and having something to do in the shed". That's what I call a good and understanding wife! During my dinner it just kept on puzzling my brains what the hell happened. Back to the wreck with the bucket of warm water to clean the mess and quick air crash investigation. While cleaning the model it finally rang in my bell, what an excessive flex of the wing tips there actually was. The tips could be flexed with hardly any effort almost 3 inches each way, up and down and the tips of the elevator stab would twist quite easily with the rudder fin flex, one and the half inch which ever way! Certainly well overlooked at the beginning of my assembly, but to my believe it has worsened to considerable degree after few weeks of flying action and water treatment. May I ad, if flying the model in a very docile manner, some might get away with the flex creating any major issue, but if you start pushing it to its limits the worse is inevitable. I'm actualy considering myself very lucky I didn't ditch it in the lake earlier which would result in lot more dramatic way. Next day after closer look and some cosmetic touch ups I decided to install additional 5mm CF spars along the rear of the wings, eliminating considerable amount of flex, but still not good good enough for a comfort. The only way to stiffen it up was to use my old trick I often use in my own design large depron build 3/D models and joining the tips of elevator stabs to the wing tips. With the use of 2.5 mm CF rods it took out almost all the flex but I have still noticed some give in the motor nacelle caused by the weakness of the rudder fin so further support was added on each side of the nacelle and the main wings. Solid as a brick!, with a simple mod, only regretting not being done right from the start. After all the repairs I gave it couple of lacquer coats on the top and 3 coats through out the bottom of the fuselage to seal it off, also creating nice and shiny finish for smoother glide along the water. While doing this I have also changed my spedo with inbuild BEC to an 80 Amp OPTO version and used external 8 A voltage regulator, this was done as a prevention in case of ESC overheating cut off, as there is no cooling airflow over the unit. Couldn't wait for the next day to see the result after these modifications, this time just in case, instead taking my fat bike I took the kayak to the lake, perfect calm morning, tho bit gloomy and grey but off she went for re-maiden. Certainly different model I have discovered soon after getting safe altitude to check its stability while pushing it through my regular aerobatic routine. Just another great experience in my never ending RC saga. Enjoy, Joseph Frost. |
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Last edited by jofro; Mar 02, 2018 at 02:45 AM.
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What a "Skippy" day! Nearly lost it on my first flight today, while at pretty long distance model facing away I have lost momentarily signal and off she went! Managed to recover only few feet over the water, still wondering how? Great footage of it, might load it on later.
Model is solid as a rock after my carbon fiber stiffeners, should have done it years ago! Great news, my article was published in the "MAS News", just got it yesterday with the great illustrations and some good English corrections by the Editor, Many Thanks. |
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Perfect day for Skippies, hardly a breeze.
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Never ending fun with little "Skippy", still alive, enjoy.
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Back in action after some lubrication.
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Back in the Skippy mood.
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3rd. Aileron servo replacement after almost losing the model due to some moisture penetration through the casing is the cost of flying constantly off the salty water.
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Finally opened the box after few weeks to see what's inside? What a surprise, finding inside the box lot of stuff I totally forgot about I ordered at the same time.
First thing, ripping out the useless decals, secondly, fitting proper hinges. to all controls. No rush with this one, it will outlive me for sure, the way my current one is going. |
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