As someone pointed out to me at an indoor meet this year... * You have made a model that is too fragile to fly outside and too big to fly indoors"
So although the VC10 has proved a point with 4 x 30mm EDFs powering a 1.4 metre span aeroplane weighing 500g plus, some changes needed to be made.

I started by stripping out all the cockpit detail, which meant evicting the crew, seats, instrument panels and bulkheads. Then some surgery on the nacelles to dig out the EDFs. This meant that I could lose one battery and one Rx from the fuselage. The biggest change was to lower the trailing edge to give a 30 degree flap, changing the lift/drag characteristics to suit indoor flight.

All the above bought the all-up-weight down to a tad over 400g, so I was ready to face the indoor group at Rochdale and give it a try in the school gym.

While the flight did not go exactly as planned, (ground-loop landing was definitely not a scale maneouvre) it proved that I was on the right track.

VC10 (0 min 59 sec)

So the answer was to try the slightly bigger flying space at the Sutton Leisure centre at St Helens. Once again, the assembled flyers graciously conceded a few minutes flying time to let me fly this monster. She floats around in a most stately manner, just have to concede that figure eights will not be possible unless outdoors in dead calm conditions. Undeterred, I have cut the wings in half, ready for fitting in a custom-built box.

https://vimeo.com/manage/videos/895484569

Thanks to Stewart Bennett for his excellent video skills.

Most of the VC10 models I have seen use the classic BOAC livery, which is certainly one of the most attractive and eye-catching colour schemes.

I wanted to do something a bit different, having read something of the political struggles to which the program was subjected. Our national flag airline seemed hell-bent on buying aircraft from the States rather than our own civil manufacturers. For further reading, look at VC10.net. The joke at the time was that BOAC stood for Buys Only American Craft.

Thus it was that I chose the RAF colour scheme used for the VC10 within what was then Air Support Command. The actual aircraft modelled, XV106, was used for VIP transport, notably for Queen Elizabeth II and Prince Philip on a far-eastern visit. Only the cockpit section of this airframe survives, but it is located at the excellent Avro Heritage Museum at Woodford, Manchester here in the UK, well worth a visit if you get the chance. You can climb aboard and sit in the flightdeck!

https://www.avroheritagemuseum.co.uk...s-vc10-cockpit


I have attempted to spray models before, but failed to draw any fluid from the reservoir. I tried different thinned paints, experimented with orifice settings, tried pressure delivery by aerosol and compressor, all without success.

So it was that I embarked on this model challenge, brush in hand, with a couple of pots of Hobbycraft's finest white and light grey acrylics, using "Lifecolour" acrylic thinner from our sadly now...Continue Reading

Well, I could avoid embarrassment and keep schtum as there was no-one there to witness it, but in the interests of a useful safety message (and comedy value) the following occurred last Sunday. The VC10 was being prepped for a maiden flight after several ground tests and taxy runs. All had been checked, but the aileron leads were very fiddly to connect when fitting the wing. I made up a couple of extension leads and headed to the flying site, the wind being light it was just about perfect.
You will have guessed that the ailerons were reversed, but the model is so light that the inevitable crash just left the nose creased and muddy but still flyable. Success at the second attempt, vid link and pic posted here for proof!

Now to paint her up without adding a ton of weight...

https://vimeo.com/manage/videos/795029952

Still loads to be done, but time for a quick view of progress.
Basic airframe and RC installation is complete, work proceeds on cockpit detailing and landing gear...may be some time!

Now that the centre fuselage is assembled, it makes sense to build the nose next and create a jig for the joining tubes between nose and centre section.

Following on from the experience on the Vulcan, I modelled the nose with a series of facets, meaning that each skin band is a simple single curvature shape, which can be unfolded to make a set of 2D template shapes.

The radome shapes are simply cut as slices in the YZ plane, to be shaped once the skins are attached to the nose.

Basic frame sections have been cut using 6mm depron.
This seems thick, but has been chosen to give a broader contact face which the external skins share.

The keel halves are cut with key slots to help locate each frame accurately.

My intention is to get a friend to make a pair of aircrew using his 3D printer, so space has been carved out in the cockpit for them.

The nacelles have been assembled on a jig to ensure accuracy. This includes the aft fuselage, allowing all the EDF units and wiring to be integrated to the sub assembly.

A tube has been built into the fin, allowing elevator and lighting wiring to be routed through to the centre fuselage.

The nacelle half shells were then mated to the jetpipe / intake duct assemblies, cutting away the trim-allowance and surplus material. This took a bit of time, with some anxious moments dressing the EDF wiring through the nacelle supports.

These were made as a sandwich of: tissue/ezdope ...2mm expanded polystyrene... tissue/ezdope

Makes for a very lightweight compound contour shape, but it is extremely labour intensive!

First, I had to make a pattern on to which the shells can be formed. this was done by turning a styrofoam block into the internal surface. This took three processes:
1. I hot-wired the blank into an octagonal shape.
2. I used a mini-drill as a lathe to turn this into a smooth shape.
3. This was then shaved and sanded to give the "squashed" section of the actual nacelle, which transitions to a circular section at the front and aft ends.

Then the shape of the final shells was made by assembling 6 shaped segments (or "gores", to use a ballooning term) together on the pattern, making a half-shell using cling-film as a release agent.
These were laminated inside and out using the tissue/EZDope process, which adds significant strength to the shells.
The final assembly to the 2 nacelle core unit involves a lot of trial fitting and fettling.

Then the whole process is repeated for the opposite hand!

The basic frame has been built in 2 and 3mm Depron for frames and keel parts. I made the schoolboy error of printing out at the wrong scale, so I now have a "sample" structure to remind me to stay focused!

The nacelle support beams were a complex shape, which could have been easily made in a light-ply foam sandwich, but I needed to keep the weight down, so laminated them from 1/32 balsa strips formed round a curved pattern.

The rear fuselage skin sections are "unwrapped" from the ruled surface shapes to make 2D templates. These were then cut from 0.5mm Vector Board.

I also built a jig in which to sit the aft fus, allowing accurate positioning of the nacelles. The rudder servo is installed and sealed under the skin, so some surgery will be needed if it needs attention.

Next time I will cover the nacelle shell build.

Using the same materials and build techniques as the Vulcan, I have embarked on a more challenging project.
It may be too big and heavy for most indoor venues and competition rules, but I feel it calling to me.
It was important to keep to the same scale as the Vulcan at 1/32nd. (I remember comparing those 1/72nd Airfix war-birds we made as lads!)
It will work out at 1.4m span, so all four nacelles will need a 30mm EDF inside. This will drive AUW to a challenging 400g target.
Work started last October (yes 2021!) on the nacelle skins, which I thought were the most challenging part. In parallel, I have been working up the CAD of the complete aircraft in my spare time. Now that I have retired, there will be more time to focus on the VC10, so now is the time for me to "go public" with progress.

More soon
Andrew

In a great day of flying at the cavernous sports centre at Walsall on St George's day 2022, I got second place with the Vulcan, behind Graham Smith's fantastic Vickers Vimy. Two classic design British bombers poles apart, displayed in miniature. We had to perform a series of pre-declared manoeouvres in 3 competition flights, as well as submitting our creations to the scrutiny of the static judges.

BMFA Indoor Scale RC Nationals 2022 Open Scale Vulcan (2 min 38 sec)

Finally, a picture taken at the Avro Museum, Woodford alongside the real XM603 and a couple of images courtesy of Bruce Corfe from a calm and sunny BMFA National Centre at Buckminster.

Now to turn to the latest project, my next blog entry will start to detail progress on a lightweight 1/32 scale VC10.

Avro Vulcan Bomber (4 min 21 sec)

Session at St Helen's Leisure Centre 13th Nov 2021.

Thanks to Bob and Stewart for their photos and Liam and Nathan for the Red Arrows flying in formation!

Here are some detail views of the lightweight EDF Vulcan.
The nose slides on, two alloy tubes engage on rolled paper tubes. Three pairs of magnets hold it in place.
The lower surface of the aeroplane is a bit light on detail, the absence of landing gear doors detracts from the scale effect, so it seemed daft to try too hard here!
The decals were designed on commercially available presentation software, using a combination of custom artwork and photos from 'tinterweb. They were printed on water-slide paper using an ink-jet printer.
The matt acrylic white is brush-painted , but is not an exact match with the decals, so the edges of these transfers are visible. Any suggestions for getting this right next time will be gratefully received!...Continue Reading

A lovely calm day yesterday, with lock-down rules easing.
This allowed me to venture out to give the new Vulcan it's maiden flight.
Flew straight off the board with CG very slightly too far aft for comfort. Video footage failed. (Stupid phone flipped to look the other way!)

Has to go back today to repeat the footage, though the wind was more noticeable and the cloud cover was heavier.
Battery was placed 2cm further forward and model behaved well.

Lockdown_Vulcan (1 min 47 sec)

I now understand what artists mean, when they say that the trick is knowing when to stop.

My wife has helped with colour mixing for the fin root antenna, as I am red/green colour blind...

I won't carry on with adding any more details now, 'twould be like putting lipstick on a pig.

Now I need to make sure I can wait for dead calm for the first flights, which will be outdoors!

Here's to a bit of freedom from lock-down very soon.

When making a really lightweight indoor model, the physics of flight loads becomes the guiding design factor. Any considerations of human handling limitations are put to one side, as they would just make the aeroplane too heavy. This is clear to see when looking at duration indoor models in flight, which distort visibly, propeller bending to take the strain as the lift and drag are balanced. Any additional mass will make the aircraft noncompetitive, so the modeller will move in a mindful slow motion as they carefully extract their model from the carry box.

This pre-amble is just to put into perspective my current challenge of building a relatively large indoor scale model. The bigger an aeroplane is, the more fragile it becomes from a handling perspective, hence the title of this blog entry. The skin of this 38 inch span Vulcan is made from Vector Board, between 0.5 and 1mm thick, which, while very light and OK at resisting shear loads and tension, fails miserably in bending. The internal supporting structure is made from Depron, which is stiffer but is quite brittle. With the help of a few judiciously placed strips of balsa to reinforce highly loaded features (ie: spar caps) all this hangs together adequately for cruising round in a nice calm gymnasium.

My challenge now is to find a way to transport the model without it disintegrating in a light breeze between car and hall.

The box I need to make will have to be small enough to fit through the loft hatch from my attic workshop, but will be just big enough to contain the model. That makes it 1000 x 660 x 220mm It must also be light enough to lift above my head. Starting with a simple 3mm thick plywood sheet box design, with an internal frame of pine 15mm square section strip, I realised shortly after cutting the first panels, that this would be just too heavy....so back to the drawing board.

The next stage is to report back when I have a workable design!

Now that the basic airframe is complete, I would normally succumb to temptation and fly the thing as soon as possible! With Covid lockdown 3 still very much in place, this is out of the question, so I shall look at the thorny issues of painting and marking next.

Anti-flash white will be the lightest finish, as the base aircraft is predominantly white anyway. (some non-white parts have been painted already) I want to try airbrushing acrylic thinned 50%, (I gather that the ideal consistency for spraying is similar to skimmed milk)
There are many useful pictures on line of our local Vulcan here in Manchester, (XM603 at the Avro Museum, Woodford) so I intend to finish the model with those markings.

The picture below shows the 3 models in this evolution:

Camouflaged XM607, my first Vulcan is now twin EDF powered, with bifurcated jetpipes. It weighs 600g and flies beautifully at the field and on the slope.

The white model in the background has flown indoors and out, twin pusher propellers are powered by 5g brushless motors in the outboard nacelles. The intakes are just crudely marked on with black paint, so the wing does not have the aerodynamic embarrassment of holes in the leading edges. This model weighs 280g and can take off using a removable "dolly" undercarriage. The propellers strike the ground on take off if I am ham-fisted with the up elevator!

The new model is shown in the middle here, waiting to be finished, currently weighing 230g with flight battery. It is not intended to be completed to a competition standard, so will not have any panel lines, pitot probes, aerials etc! I might manage control surface outlines and waterslide markings.

Time for some catch-up photos as lock-down two continues, I am now into the fourth month of this project. (Funny how things always take longer than planned, but hey, I am enjoying myself!

Wings are now skinned, albeit with some dodgy joints in evidence. I am currently using copious amounts of lightweight filler to hide these blemishes. Rx fixed in a location which should allow plenty of battery location choice, depending on CG needs. Nose now needs to be located accurately and retained with tiny magnets. Has to be removable to get the 'plane in a custom box which will fit through the loft hatch, or it will never get out of the workshop.

Struggles with tiny connectors have concluded now that bigger 3 pin connectors are used.

Tried to fill in the main undercarriage frames with VB sheet to look like the real outline around the doors, but one leg mechanism touched this new edge and stalled the servo. Before I knew it, the air was filled with that unhappy smell of fried electrics. Bu993er it! One servo down, order another from micronradiocontrol pronto!

Mass target was looking good until I started thinking about painting the beast.

Well, after building 2 Vulcans to my own design templates (1/32 scale), one for outdoors and one lightweight indoors, it is time to embark on the bigger challenge of an indoor EDF powered Vulcan with retractable undercarriage.

Unlike the first Vulcan, which now weighs 600g and flies off slope as PSS or flat field power, this one will be made using Vector board for the skin parts, which is lighter than Depron. I am still using Depron for the framework as it needs the stiffness which Vector board lacks.
My target AUW is 250g. This is challenging as my first indoor example weighs 275g which has twin BL propeller drive but no retracting gear.

The new model uses Eflite UMX A10 EDFs, which is driving me to use the Rx from that model too as it has the twin ESCs on the Rx board.
There are two problems with that: Firstly the XPORT mode is locked, so CH5 and CH6 are not available. (need one CH for retracts)

Vulcan_Undercarriage (0 min 10 sec)

Secondly, this mode lock does not allow me to assign elevon mode correctly to the two wing servos. This is doin' my head in, so if anyone has worked out how to wrangle the correct servo sense for elevator and aileron controls in this set-up and explain it to me, I will be forever in your debt.

One alternative is to ditch the A10 Rx and get a pair of external ESCs rigged up to a standard AR6400 board. They will have to be able to cope with some higher current, as the six mosfets needed dominate the A10 board.

Another answer is to actually carry 2 Rx on board, the A10 unit just copes with twin speed control, the other does flight controls and U/C.

All good fun anyway, keeps me busy in lock-down.

Cheers

Vulcan_First_Flights (1 min 58 sec)

So, here I am with a shedload of 2mm Depron. Question is, can I make a decent sized model with it?

Step 1, Make a CAD model of the aircraft.
Step 2, Approximate the compound fuselage shapes with a simple faceted version.
Step 3. Spend a merry few weeks printing, cutting and glueing parts together! Note that various moulds, forms, cylinders and other shapes available in the workshop were pressed into service to help form the required shapes.

I can recommend "Canopy Glue" as a really good PVA, though it takes a while to dry properly and can slow the build if it is the only adhesive used.

I am currently shaping and panelling up the rear and lower fuselage skin sheets