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Evolan - Concept Design to Moulded Model

[Flight of the prototype No 2]  [ Test flying complete]                                                                                                   [Evolan Assembly instructions]

Over the years of building models, finding new techniques and just wondering how do they do that, I have logged many questions in the mind vault until the opportunity arose to either ask or discover the answers.

None more so than whilst having a general idea of vac bagging, initially, it all seemed too difficult. But to watch someone doing this only to realise that it is an easy and fairly simple process, it’s just a different way of doing things, which only requires a few additional bits of kit to perform, and if like me, you can adapt equipment to suit (eg an old fridge compressor for a pump), it doesn’t have to be expensive. Once tried, never to look back and use the technique more and more, wondering why I had not adopted the process before, it would have certainly helped on many of my previous projects. This was recently applied to the manufacture of a decent building board – see “how to” article.


Over the years having owned a number or moulded models, and scrutinised many more, wondering how hollow wings are actually made, How many layers of cloth, types of reinforcement and how are the wipers on the controls made….. Lots of questions.

A couple of weeks ago, I was a little unwell which kept me off the slopes, out of the workshop, and off
work for a while and I found my way to YouTube in an attempt to discover some answers. There are many threads / videos out there, all variations on a theme to achieving the same goal. With my head full of questions an armed with my note pad, I began my quest to learn, I set to work watching what I call “Trade Training “ videos. Well, it beats day time TV by a long way…..


To cut to the chase there are a few people out there that offer my kind of experience in the videos that they have made available and whom I could relate directly with what they were doing with some informative banter as they progress through their respective tasks. There are a few nutcases (meant in the nicest possible way) out there too, but while these offer a source of entertainment, they can often fill in the gaps of knowledge or at least present yet another question. The secret is to watch and learn; sometimes coming out of the experience with more questions than answers, but eventually the search yields the secrets.

Needless, to say, I was eager to try out some of this new information and techniques. Firstly Spraying the paint onto the Mylars prior to the glass epoxy lay up for vac bagging – saves having to paint afterwards …. Success !!!! Cutting the controls from the wing without the need for additional hinges (using a Living Hinge) Success!! Making the wipers for the controls on the wing…. Again success! but room for improvement and so on.

I have even discovered how to make moulds to achieve the retail quality of the products available. Having made and used some moulds which are fine for what I do but can often result in minor imperfections in the moulded fuselage – nothing a little extra resin of filler can’t resolve; I always wondered how they achieve the necessary standard of quality. Simple as using a bladder inside a different type of mould and used to push the cloth and resin into the nooks and cranny’s to ensure that there are no bubbles or imperfections………. Even down to how to make the inflatable bladders.

Armed with the knowledge, just needing the practise, I decided to create a new model, a small flying wing, the end goal being to create a small fully moulded model.

Meet Evolan - a new concept model, to develop the skills and techniques necessary; if it turns a few heads, then so much the better.
After a little design work, and keeping the design relatively small to ensure that I didn’t waste too much material during the development and learning process, the wings were cut from closed cell foam (Floor mate / Jackodur -extruded polystyrene) to the chosen plan shape and Aerofoil (MH45). With the necessary conduits installed for servo wiring, the wing halves were assembled as a once piece wing. The Mylars were cut to allow the glass to be transferred to the foam cores.

The mylars were lightly spray painted using some old part cans of paint. Well, it was a good enough excuse to have a clear out too. The paint was allowed to dry overnight, before the glass was laid up on to the mylars with epoxy. The leading edge and tips of the foam cores were reinforced with Glass and some carbon followed by the whole one piece wing being sandwiched between the mylars and vac bagged overnight.

A day later and the moment of truth to see if the technique of painting before layup had worked….. Oh Yeah!!

When the myalrs were peeled away from the cores, the mylars came away free of any paint which, almost by magic, had been transferred to the wing with a really good finish. The paint could have been thicker providing a more opaque finish, but I was using what paint I had left and it was always my plan to have a light paint finish for the first wing, if nothing else but to keep the weight down. There was some trimming of the leading edge, tips and trailing edge to complete, but otherwise a really good start.













After a couple of days of curing in a warm room, the servo recesses were cut using a hole cutter and dremel router tool. The leading edge wing dowel and tube fabricated and installed and the Elevon controls cut free. This was also the first set of wings using new techniques that I managed a consistent method of getting the installed living hinge to work without the fuss – no hinge tape required this time! Even manufacturing and installing the wipers that seal the control surfaces. This really worked well as during the test flight, the model was almost silent when flown at speed, more on this later.

A couple of Hitech 65MG installed on the Elevon controls and set up on the radio gave a slope free and responsive installation.

The fuselage was the result of another lost foam exercise, used on some of my other models (SmArt, Volitan). The shape was carved and sanded in closed cell foam, wrapped with epoxy glass and once cured, the foam was removed leaving a one-off glass fuselage. The fin was fabricated out of 3mm Balsa and covered in 25g cloth and resin. Once cured, it was trimmed and install in the fuselage tail boom.
The fuselage was given a coat of paint to match the upper wing surface. The battery, switch and Rx installed and with the model assembled, the model was balanced on the calculated CoG position. Two weeks from start to finish, and the model was essentially ready for its test flight.

The test flight could not take place the following weekend as I had planned to go down to Neils’ for a thermal soaring event. But I took the Evolan with me along with many other models, if nothing but to test glide it over some long grass before committing to the slope. A Quick teak of the CoG and it was ready to go.

The following Sunday after the initial rain proved to be good, so off to the local slope mid-afternoon; the sun was out and there was a steady breeze. Getting to the top of my local hill flying site, Parlick was a pleasant climb. The wind was a little fresher than expected, constant 16mph gusting 26 mph but ok.

I flew the Volitan for a good while to check out the conditions which, other than the occasional gust was free of turbulence, landing proved challenging as landing on many slopes you have to land on the face in good lift, but all was set for a test flight of the Evolan.
After the obligatory static photo shoot, I set up the camera on the gorilla pod and set it atop of the dry stone wall to record some video of the first flight(s). With the CoG and control checks complete Evolan was launched straight into wind. Slight down elevator was needed to get it to penetrate the stiff breeze and it was noticeable that the model was in need of some Roll differential. The model was landed, a small additional amount of nose weight added to help with the penetration and some differential dialled in and launched again.
The model was launched, checked and landed several time to make adjustments to the differential, finally arriving at 80% more down than up (opposite to a conventional model) and some lead (ballast) on the CoG to provide more penetration in the prevailing conditions. Well, the model is very light topping out at just 430g AUW.

A further and more prolonged flight ensued with a sprightly turn of speed and manoeuvrability. Indeed, the gradual application of full up elevator was used to get the model to drift backwards , stalls were predictable and straight and if full elevator was applied at speed the model did not screw out it just did what was asked of it, although it did bleed the speed off dramatically, something that was practiced and used on the final landing to good effect which arrested most of the forward speed before a gentle landing in what was becoming quite blustery conditions.

More and more clouds were gathering in the distance, some clearly producing rain, and the weather was coming my way. Given a 15 - 20 minute walk back to the car, I made a hasty retreat and went home very pleased with the afternoons outing and results of the test flight.
More outing to follow in different conditions, but first impression was this will be a good little model, just right to progress to the moulding stage.

Watch this space for my updates as this exercise progresses.


April 2016


It's been a while since I wrote about my flying wing, Evolan, so I though I'd better bring you up to date.


If I said that Evolan is a really special model, you probably would not believe me, but it's true. I take it on almost every trip to the slope and is definitely one of my favourites. In fact, on the few occasions that I've given the transmitter to my flying Buddy, Neil, it has been a challenge to get the Tx back off him.


The glassed foam wing has proven to be quite durable and quite resilient to knocks. The model has been tweaked, benefiting from Differential Elevon on Roll. however, unlike most conventional models, most flying wings require more down than up aileron, Evolan is set 80% up, 100% down giving a nice smooth roll. The model raced around in most conditions, but initially suffered from lack of inertia in loops and bunts. Adding a little ballast on the C of G gave it the performance I was looking for.


Last week I took the model down to Leek and Moorland, Staffordshire - a great range of slopes and whilst the conditions were fairly light and variable at "The Gate" slope site, Evolan ripped around when others were only just holding their own. The secret is to let it fly, let it move without the temptation to hold back the elevator, but that can be said for most models.













An impressive view, those are the Jodrell Bank telescopes in the distance.

Given The flying wings' performance, and the encouraging comments from everyone that sees it fly, I am now progressing Evolans' design.


I have made a new fuselage, a little more aggressive in appearance and one that can be moulding easily.


Before I commit to making moulds for the wing, as this is the model I want to fully mould, I have just one more trial to complete. I have already created a new wing with a different wing section just to compare their performance. Why you might ask?


Well, I have heard a lot about this new wing section, and that it achieved the world record for the fasted flying wing, then I have to give it a go.


The wing planform is slightly different, rounding the tips a little more, but everything else remains the same. I have cut the cores and glued them together and painted the mylars yesterday. This morning, I laid up the glass skins and put them in the vac bag. These are now well on their way to curing, under their heated blanket. I'll switch it off tomorrow before going to work. Tomorrow night, I should be able to check on my handy work.


That's it for now. I'll report back soon........


Monday night (Next day) and time to check on my handy work.


The wing was carefully extracted from under the quilt and electric blanket and removed from the vac bag. The moment you release the mylars is always a tense one.

But I needed not to worry as the paint had adhered to the cloth and resin well and and came off the mylars cleanly leaving a high gloss finish. Unlike my initial attempt at painting the mylars on my first wing, this time I had layered the paint and finished off with undercoat leaving it overnight before laying up the wings. I am mightily impressed how bright the colours are on this new wing.



With a mylar lay up, there is always a little trimming and smoothing of the leading edge and tips and I had just finished this task before taking the photos. I will be touching up the leading edges with some coordinating paint, but I have now put the wing back in the outer foam blanks and weighted it down with a view to let the resin fully cure over the next few days before I cut the Elevons and release the hinge and cut the servo holes.


I will report back when this has been sorted.



    A coupe of evenings in the workshop has seen the model totally re painted. The initial paint job straight out of the mylars was good, but glue fingers, really sticky masking tape.... (that normally isn't the case) and other bumps and  scratches really messed up the paint finish, so I rubbed it down and started again. I think the new colour scheme, although similar, work better.

I also made the Elevon servos and control link a little more self contained and instead of control fairings for the servo arms I decided to keep most of the control arms in the wing, and used a servo cover with a bulge and a really small fairing on the control horn side of the wing. All up, I think this has worked really well. Take a look for yourself.


07 May -Warm, dry and a good breeze
The conditions were good for a days flying and to get the air under the Evolan Mk2 wings. I had completed the radio installation last night and balanced the model on the calculated C of G position.

Parlick Fell, my local slope was the venue and after the normal Saturday morning shopping, I ventured up the hill, and met one of the local modelling stalwarts, Ron, up at the top. No one else had turned out to fly, maybe put off by the constant 27 mph, gusting 32 mph Easterly wind. But it was warm and dry and the lift was remarkably smooth. mind you the Easterly face and the bowl to the left always provides good lift. That's why the para glider fraternity like it so much, but they had stayed at home given the wind strength.

First of my models away for a test flight was a new little project which can be found on a different page. Pocket Rocket.....

Next was to fly the original Evolan, primarily to gain an insight into how it flew in today's conditions as a benchmark to compare the new model against and this was done with no fuss and it flew well in the conditions.

After a thorough range check of the Mk 2, its initial launch of the new model was back from the slope edge and it didn't go very far as It was a little sensitive on the elevator and not enough reflex for the initial C of G  position which was a little forward, or so I thought. Second launch and it was away, but again a little over sensitive on the pitch control. Although I had copied the other Evolan control settings, it was clear that this was different and certainly needed the exponential sorting out. After a couple of minutes I landed the model, there was so much lift that it was difficult to land any models but I got it down without too much hassle albeit a little fast.

Subsequent flights saw the C of G moved forward 5mm and the Exponential on aileron tweaked over a number of flights and are now set at 75% Up, 100% Down, the opposite way to a normal conventional aircraft and its now pretty close to an axial roll.

The model looks good in the air but does not seem quite as fast as the other Mk1 model, and it does have the yaw oscillations at slower speed that seems synonymous with a lot of tailless models . I had made the wing to fit both the new fuselage and the old one from the Mk1 so I swapped the wings over and flew both models again. The wings on the new fuselage displayed the same yaw issues, whereas both wings on the old fuselage, was good. To prove that the fin size needed to be enlarged to eradicate this problem, I taped the removable fin from my little experiment model onto the tail of the Mk 2 fuselage to increase its effective area and flew it again - problem solved!!!

The first flights were promising, but the jury is out on which wing is the best all-rounder. At the moment I am airing on the side of the original wing, but again, we'll see over the next few weeks.

I need to check on the parameter of each wing to make sure they are both the same percentage thickness etc

I now have a list of jobs to do in the workshop to get this permanently sorted. however I think that you will have to agree, that the new model certainly looks like it means business.


I'll report back again soon.

Jan 2017.

2016, saw lots of flying of my models, not least the Evolan. Indeed, the Evolan and the Midge were the models I preferred to take up the hill most days.

I have had many flights in varied conditions with both version 1 & 2 of the Evolan. The fuselage and wings have been swapped between each resulting in the fin area of the 2nd prototype model being increased to stop the wobble in turns at slower speeds.

Once the minor modification were complete and many more flights under my belt, I am really pleased with the outcome and have decided to progress the model to the moulding stage. The moulded model will feature the original wing section with the plan form and fuselage shape of version 2. I have made the fuselage and wing plugs and these now being processed to make the moulds.

Succumbing to pressure during one of my visits to the Leek and Moorland slopes, I sold my 2nd prototype to a good friend, Mark Ollier who has really warmed to the model. Having tweaked it's trim to suit his style of flying, he never fails to turn heads when he flies the model, which I am told is most of the time during which, all you can see is a big grin on his face. In high wind conditions, Even at just an All Up Weight (AUW) of just 580g for the 1st Prototype and 620g for the 2nd proto type (Mark's model), the Evolan needs no ballast, just a little down trim and it comes alive easily coping with everything the slope and the weather throws at it. 

His trips to places like the Great Orme and flying in all conditions from light lift to gale force winds has always been followed up with a text message or email, often with photos. After one such trip he contacted me to tell me how well it flew, and I quote:

"40+ mph winds plus Midge & Evolan = Bloody Awesome"

Mark has really pushed the envelope to the extreme and never fails to impress onlookers with his flying of both the Midge and Evolan models resulting in many questions of; What is it? where did you get it from?, where can I get one?

 Well its here, at Slope dudes.

Watch this space for the fully moulded model nearing its production..... the Fuselage Mould is almost complete.

Jan 17,

I have a number of projects on going at the moment, and steady progress is being made on each. I have now produce the Fuselage mould for the X-2, the first of the X-2 fuselages has not been used on an X-2 as the wing mould is still being sorted. It has however, been used on a new Project X, which has an obechi veneered wing which has been vac bagged and then glassed again to finish, making one very strong wing.

The model is looking really good and has already been balanced and had a few test launches on the flat to make sure that it would fly straight and respond correctly. I have just to get it up the slope now, but the weather is being a little bit mean and cold presently. I have also made myself a new Midge, given that I sold my original prototypes back in October (boy have I missed these!). This also is ready for its inaugural flight.

The fuselage mould for the Evolan has also been completed; this is in advance of when I expected to finish it. This is primarily because I was approached to provide a vac bagged wing and fuselage for the Evolan, so it was an opportunity to prioritise the fuselage mould. Just got to lay up the first fuselage now and make someone happy that he has got hold of one of these models.

The mould has been polished and prepared for the first lay up over the next few days seen here with a midge fuselage mould also ready to lay up.

Once I have sorted these out, it'll be time to continue the X-2 wing mould so I can develop the skills to then progress to the larger wing mould of the Evolan.

These are such exciting times given that I have got a collection of models that really get people talking when they fly, as they are unusual and perform very well in most conditions. Indeed, my X-1 (foam version of the X-2) was flown on Xmas day on "Gummers How" in the lake district in gusting 40+ mph wind conditions. A few clicks of down trim and it just accelerated away from the slope and whizzed around - loops, very quick rolls and all without making much of a sound, its a really quite model. One could also be excused thinking that it must have been ballasted up, but this was not the case, given it's size (26" w/s) and particularly light wing loading (9oz Ft/sq) even I was pleasantly surprised at how well it performed on the day.

I didn't fly for too long on the day, the cold biting wind and the fact that I was on a walk with my good lady, but paused long enough to have a fly, before completing our circular walk followed by our festive picnic.

As soon as the Evolan comes out of the mould I'll be back to give you an update........

Early Feb 17

Over the last weekend, I laid up two fuselages. A midge fuselage and of course, the first Evolan fuselage. It is always a worrying moment when you come to release the mould, but I need not have been worried, the model came out of the mould fairly easily and with a reasonably good finish. I am very please with the outcome. This one is already spoken for, and has already been despatched to its new owner with a foam glassed wing.

I will be laying up another one soon, which will ultimately be mated with a fully moulded wing, but the moulds for this has yet to be completed.

More info to come as the fully moulded Evolan progresses.



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