- Concept Design to Moulded Model
[Flight of the
prototype No 2] [ Test flying
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”
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
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
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.
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.
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
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
Watch this space for my updates as this exercise progresses.
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
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
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
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.
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.
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
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
I'll report back again soon.
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
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
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.
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
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.
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
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
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