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WOTZAT I hear you say????

It’s not every day that something really special comes along, but the more I fly my new creation the more I like it……

So it began a little while ago, while flying on my Northerly slope, Jeffery Hill, I was having a chat with a great bunch of guys also making the best of the North facing ridge. Talking about models of course, they were enthusiastic of my collection of flying machines. It was through one of these Rivington Soarers that I was put in touch with another of their group, Mick, who wanted a new set of wings for his Jart. Well one thing lead to another and during a meeting in my workshop I was invited to Winter Hill, at the heart of the Rivington soaring association slope sites and not too far away either.

A good North Easterly was blowing and it was duly arranged to meet up on Winter Hill under the TV Aerial mast. I wish I’d met up earlier in the day , as the conditions were fantastic - a really nice ridge just a very short walk from the cars and a good breeze. A lively bunch of modellers were already there making use of the strong constant lift.

 There were a good selection of models on show; a Typhoon mouldie, Vulcan bomber, BD5 and many more. One of the models that was putting up a lively performance was a flying wing called a “Poky 40” and I was quite taken with how quick it was. A few of the usual questions of what is was and where did you get it saw me researching the Poky on the ‘net.  

A few weeks on and a moment of daja vu when I was chatting with another good friend from down in Staffordshire who wanted one of my Evolans that he said had also taken receipt of a Poky from the Germany company at www.stratair.com

The seed had been sewn and it wasn’t long before I was challenged by a few good friends to make a model that could possibly rival the Poky. I had been thinking of such a project and as I already had a baseline from which to work it didn't take long to make a start. So over the next couple of weeks using my Evolan model from which to develop a new faster model, I formulated a set of dimensions and had a selection of aerofoils to choose from. A set of vac bagged wings soon took form and I made a lost-foam epoxy glass fuselage to suit.

   

A couple of new thin Emax 3352 servos had arrived in the Xmas post, so roll the clock forward to current day having been away for the festive holiday, I was desperate to get back in the workshop and onto a hill to fly. It didn’t take more than a few days to finish off my creation, paint and install the radio. The model was taken to my local farmers field for a test launch which confirmed the C of G at 18% was a good starting point and with no trim change it was ready to get it out on to the slope.

The following day, New Years Eve (‘18), I managed to get up onto Parlick with a nice Westerly wind gusting 25mph. For most, it may have been a little too cold especially with the wind speed and the associated wind chill, but I was not deterred. I know the hill well and this type of model just begs for some good compressive lift so I didn’t have any concerns with such a wind speed for a test flight.

Having checked out the conditions with my Evolan, I then chose to launch the new model. Following the necessary pre-flight checks it was launched into the big blue yonder. Not so much blue, a cloudy dull day actually but with some good lift. I had dialled in a little too much reflex for the launch which saw the model climb straight up, elevator style from the gentle chuck. The launch reflex had been set up on a switch so having cancelled this, the model just started to build up speed, faster and faster with only a few tweaks on the elevator trim.

The C of G was indeed a good balance, with little tendency to pull out of dives on its own. Rolls were not as crisp as expected but were good but needs a little more throw to achieve. The stall was non-existent through normal control inputs.

Tight turns were surprisingly good with little speed lost and I was soon into the groove so to speak. Loops, rolls even a bunt didn’t over challenge this speedy little model. Not a model to take your eyes off while flying though, as it covered a huge amount of sky very quickly but a model that certainly gave me a buzz and a big, big grin!... A success!

A few passers-by, ramblers making the most of the dry weather asked the usual questions; that’s unusual, Did you make it, what is it etc, leaving me with a dilemma…… what was I going to call it,  so I have temporarily given it a title of “Wotz@” (Wot-zat) for obvious reasons.

Well that’s it for now as Breakfast is calling, and given that the first day of 2019 is sunny with a Northerly breeze, I’m going to go to Jeffery Hill to fly my new creation a little more, along with my usual go-to models, Evolan, Midge etc.

The first flight is now on Youtube at the following link

 

The first day of 2019, saw a light breeze from the North, but on arrival at Jeffery Hill, the wind seemed too light to fly. Even the Paragliders were having problems getting airborne.

I did commit the new model to flight and managed to fly it around gently for a few circuits but the wind was too light. I tried one of my other models, but the conditions proved too light also, so I went home.

The weather over the following few weeks has not been too kind, given low cloud, rain but good times will return and I’ll be ready.

In the meantime, being so pleased with the model I am already making a plug for the fuselage mould and have cut another set of wings with slightly different dimensions to compare performance. Time will tell.

Happy New Year for 2019.

Roll the clocks forward to what is now approaching the end of January, the weather being pretty poor since the first flights, and the forecast to be much the same for the next week but Sunday 27 Jan saw North – North Westerly wing a forecast of wind speed between 40 and 57mph. Well it turned out to be a bright day with sunny intervals and the clouds were moving pretty fast. Not to be deterred, I thought I would venture out to Jeffery hill to see if it was flyable. On arrival a couple of other modellers had just arrived with a collection of foamies, SAS “Wild Things", I think.

After the short walk with all my cold weather kit on, I checked the wind speed. The forecast seemed a little excessive, it actually measured 35 - 49mph, although during my first flight it seemed like the occasional gusts were much stronger causing me to find a better footing to stand upright.

Once again, the “Wotz@” just ate up the sky giving so much confidence in its controllability and leaving the heavily ballasted “Wild Things” almost stationary in comparison. I had slightly increased the aileron deflection which improved the roll rate with no trepidation in flying the pocket rocket around. The model just oozes confidence and one that I just want to fly more and more.

I have decided to make a proper mould for the fuselage and to try a slightly higher aspect ratio wing as a trial to find out if indeed I have already got the perfect formula or if it can be improved a little more. How? Well I don’t know but it’s worth having a play with a slightly different wing to compare.

In the meantime, I am wishing for some nice weather to go slope soaring again soon.

 

Feb 2020
I can’t believe that it’s a little over a year that has passed since this slippery design took flight, and a lot has happed since its concept.

Making the fuselage mould has being somewhat eventful with problems with tooling gel coat and release agent. I used to use Polyester gelcoat and resin for my moulds and have not had any problems until I started the Mould for this model. A few trials and tribulations, I’m playing it all down a little......... its been a Trial!!!!! lots of lessons learned and I now use epoxy for my moulds. Much easier to work with, although a little more expensive, I think well worth the investment and I’m now back on track.

I also decided to make a mould to utilise an internal bladder system to help improve the fuselage mouldings. The inflated bladder pushes the cloth into all the nooks and crannies, it makes a better job of the seams and actually pushes out unnecessary resin, which results in a strong and much lighter fuselage. This technique was new for me, but a few you tube training videos later, I’d got it sorted, and the added bonus, is that it doesn’t take all day to get the two halves of the mould joined. From start of the lay-up to joining now only take a little over a two hours, where before, a couple of hours to lay up then wait till the resin has gone "green" before trimming and joining. effectively an all day event which need a planned approach.

The use of modelling balloons to inflate from the inside of the fuselage can be seen in the photo. Clear resin, with balloon pulling the guide tube and balloon adding colour to the moulding until it is removed. Removal of the balloon is fairly easy given a little patience. Gently pulling the tube and the end of the balloon see’s it releasing from the internal contours of the fuselage.

Once the resin swarf is trimmed from the moulding seam then everything is good to go, with just the cockpit and wing wiring openings to cut out.

Feedback from friends who had me cut them a few wing cores, which they married up with a range of home brew fuselages, has been useful. Whilst the little 40” model continues to blast around the slopes, a new idea that was suggested was to increase the wingspan a little to see how it would fair against the original design. A set of 48” cores for a friend which were vac bagged with 100g uni-direction carbon making for a really strong wing. He married these up to a homemade lost-foam epoxy glass fuselage, which worked really well. The vtrst flight was good and later putting 7 oz of ballast in it made for big manoeuvres with the model retaining energy well.

Another good friend had me cutting a set of 50” cores for him and I decided to put one together for myself as well, which I planned to marry up to to the first moulded Wotzat Fuz.  Given the steer and a source of 100g uni-direction carbon from Easy Composites, I also laid up the cores with a layer of 100g uni-carbon and 80g glass in the vac bag and with the addition of a carbon leading edge, I have been so pleased with the results.

Without waiting to paint the model, I cut and freed the living hinges for the Elevons and fitted the gear. 2 Emax 3352 MG servos for the wings and a 2/3 AF NiMh and mini receiver to the Fuz. A little moulded nose weight and I had the model balanced at 18%.

The first flight was in fairly light conditions which saw the model buoyantly flying lazy figure eights with good speed. The following weekend, had me travelling down to the Leek and Moorland slopes joining a good crowd at the Mermaid pool slope.

Not a weekend for the faint hearted, Initially the 50mph high winds measured at the top near the cars, and slightly lower down on the ridge - a cold brisk 45mph. Conditions got worse as the day progressed within increasing wind speed and punishing gusts causing lots of turbulence.

I decided to give the stretched Wotzat model an airing. A bit of a challenge for its second flight, but I had confidence in its pedigree and having put 170g ballast in the fuz on the CoG, it was all or nothing. The model launched well and proved a success. It scooted around in the turbulent conditions with an air of grace. Loops were big and whilst the roll rate had been improved with greater control input from the first flight, I hadn’t got the aileron differential quite right with the rolls initially a little wobbly. Its second flight of the day was better and rolls much more axial having made a few tweaks to the transmitter settings, but there is still a little more tweaking required. I was really thrilled with its performance and only the bigger gusts of wind during turns had an effect on its composed posture. I was fairing a little worse by having to go down onto one knee to stay upright in the punishing conditions. I figure that for these conditions, more ballast would help the model and I have prepared a 300g slug to fit in the fuselage for next time we have a big blow, maybe a trip to the Great Orme, assuming I will still be able to stay on my feet in such windy conditions.

To compare its performance, I launched the smaller, 40” version into the extreme weather. 120g of lead ballast added first, and as before, the launch was uneventful. The smaller model was less effected by the turbulence and felt good on the slope. Not bad for a AUW of 500g!

I am now finally putting a little colour onto the new 50” model, it’s a shame to cover up the carbon, but I do like a nice colour scheme; In fact, the unpainted model was at times, difficult to see against lower reaches of the valley floor. The current weather isn’t conducive to painting the model though, not wanting to make a mess of the workshop, requiring a dry fairly calm day to warm up the paint, rush outside to put down the colour on the airframe and rush it back inside into the warmth to dry. Not ideal, but I don’t want to have to wait till the summer to finish all the paint jobs.

A week or so on, and a break in the very wet and windy conditions has allowed me to finish the painting which I am quite pleased with. I even got the underside paint to give me a carbon effect weave texture....
 

Now for more flying once the latest storm Dennis has died down............

 

 


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