RCM&E July issue 20-Page FREE preview

FREE COLIBRI PRO-PLAN! Colibri Swiss Homebuilt

Gloster Gamecock VOL. 66 NO. 7 JULY 2023

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& OTHER HIGHLIGHTS AT CLASSIC PROPS

1911 DEPERDUSSIN GIANT SCALE EDWARDIAN

INDOOR SCALE NATS SMALL WONDERS AT WALSALL

FRUITY RADIO

LATEST LEMON RX ON TEST

PLUS II 4-MAX UPGRADE - MOTOR SET SWAP II SC STRIP DOWN - GLOW ENGINE REFURB

WELCOME Editor: Kevin Crozier. Mortons Media Group, Media Centre, Morton Way, Horncastle, Lincs LN9 6JR kcrozier@mortons.co.uk

W

elcome to the July 2023 issue of RCM&E. Our town has long had one of those discount supermarkets famed for its centre isle bargains.

But it’s a relatively small store and parking is a bit of a nightmare, especially as it seems to attract the kind of driver who tend to throw their large SUVs in at random angles. It’s only a few minutes away but it’s also up a busy road, hidden behind a parade of older shops, so it’s easy to put to the back of one’s mind if you’re the kind of person, like I am, that is attracted to their famous centre isle to scour it for cheap tools and other bargains to populate a model building area with. In fact, I haven’t been in there for quite a while, not since the last time that they had rapidly depleting stocks of their long-awaited small foam gliders (by aeromodellers at least!) which are ripe for conversion to radio control.

However, just before last Christmas this supermarket’s main rivals arrived in town, championed by an orange vegetable with the same forename as yours truly! Their shiny new store, much larger than their competitor’s, has a big car park with enough room to park well away from the ‘throw it in sideways’ merchants. And, to make matters worse, it is only a short walk away and is situated just off the main road that I have to take every time I go flying.

Of course, such temptation is now very difficult to overcome and I find myself inextricably drawn to the delights of its centre aisles at least once or twice a month, often on the slightly tenuous grounds of volunteering to nip round for some item missed from the weekly shop. Even if there’s nothing to immediately attract my attention their dastardly marketing coves have a cunning ploy up their sleeves by lining the packing shelves just after the checkouts with thin brochures advertising soon to be available bargains, with the hard to resist tagline, ‘Available in store next Thursday!’ This has worked at least twice recently, the first requiring an early morning dash to grab a voluminous ‘Angler’s Backpack’ to replace my well-worn modelling rucksack. Then, only last week, I was at it again, this time sniffing out the location of some neatly packaged ‘precision’ hand tools. I really only wanted to look at the micro drill set but ended up with their small hand saw and tiny screwdriver bit sets too! Oh, and while I was at it, those bargain

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pegboards looked very handy, especially as I was just about to start hanging up some of my expanding modelling tool collection. Two of those as well, please…

So cunning Kevin has got me in his firm grip. I think I need some non-retail therapy!

It’s time now to take a brief look at what we have lined up for you in the July issue of RCM&E, starting as usual with our regular columns.

In Retro Ramblings, Shaun Garrity buys a remodelled Graupner Kwik Fly which once provided shelter for a mouse and its many relatives. Shaun also looks at DB designed Micro-Mold kits and pays tribute to MFA. Next, in One Man & His Shed, Dave Goodenough starts to clean up a bargain priced SC glow motor.

Tony Nijhuis returns as the designer of this month’s Pro-Plan feature with the latest EDF model in his new Mini Jet series. This time the spotlight falls on the F9F Panther, which has numerous colourful schemes to choose from.

Our feature articles begin with Ian Turney-White’s description of his new giant scale Edwardian era aeroplane, a mighty Deperdussin from 1911. Mike Freeman is next, taking the lead to describe some of the things to consider when choosing a servo for your next R/C aeroplane. Then it’s time for this month’s event reports, starting with Danny Fenton’s photo essay hot foot from the Scale Indoor Nationals. Barry Atkinson has been out and about with a camera too, joining some of the UK’s top pilots at Classic Props as they headed for Wales for a relaxing weekend of propeller driven fun flying.

On review this month John Stennard builds a well thought out Discus Launch Glider kit, the Kavan Cumul, before yours truly looks at pepping up the aerobatic performance of an old airframe with a little help from 4-Max Models. Shaun Garrity finishes off this month’s reviews as he flight tests the latest ‘Generation 2’ receivers from Lemon.

I hope you enjoy reading it all.

Happy Flying!

www.modelflying.co.uk | July 2023

CONTENTS

RADIO CONTROL MODELS & ELECTRONICS I VOLUME 66 ISSUE 07

ON THE COVER

Photo: Barry Atkinson Mark Parker’s Laser vee-twin powered Gloster Gamecock is a real stunner, built to the highest standard. Mark’s model was one of several fine scale models that visited the Classic Props event held on the last weekend of July 2022 near picturesque Usk on the Welsh borders.

Reviews

88

10 KAVAN CUMUL

Regulars

22 MAXED OUT

8

SWITCH ON

Our latest round up of model flying news.

36 COUNTERPOINT

John Stennard builds a well thought out Discus Launch Glider kit.

In the search of better aerobatic performance from an old airframe Kevin Crozier turns to 4-Max Models for advice

64 FRUITY RADIO

Shaun Garrity flight tests the latest ‘Generation 2’ receivers from Lemon

A selection of new gadgets, kits and bits for you to buy

44 ALL WRITE

Have your say in RCM&E’s monthly chat room

78 GOING PLACES

Our monthly list of model shows, events and competitions for you to visit over the next few months

94 MARKETPLACE

Sell off your unwanted airframes and engines or maybe buy a few new ones

95 NEXT ISSUE

Take a look at what’s coming in the August ‘23 issue of RCM&E

98 PARTING SHOT

Bob Jennings’ mighty 102” BAe Nimrod MRA4 heads low over sunkissed waves

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64 22

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www.modelflying.co.uk | July 2023

48

16 Features

Columns

28 DEPERDUSSIN

Ian Turney-White describes the build and maiden flights of his latest giant Edwardian monoplane

38 SERVO SCIENCE

16 RETRO RAMBLINGS

Shaun Garrity’s musings this month include a rodent wrecked Kwik Fly, more Ken Willard wonders, DB designed Micro-Mold kits and a tribute to MFA

72 ONE MAN & HIS SHED

Mike Freeman offers advice on some of the things to consider when choosing a servo

Dave Goodenough starts to clean up a bargain priced glow motor

62 SUBSCRIBE…

80

... and receive Luftwaffe Fighters & Sea Harriers FREE!

80 SCALE INDOOR NATIONALS

Danny Fenton reports from the BMFA’s spring scale bonanza

88 CLASSIC PROPS

Last July some top pilots headed for Wales for a relaxed weekend of propeller driven fun flying. Barry Atkinson joined them with his camera

28

free pro-plan

48 F9F PANTHER

72 July 2023 | www.modelflying.co.uk

Tony Nijhuis returns with the second EDF plan in his latest series of Mini Jets

All reasonable care is taken in the preparation of the magazine contents, but the publishers cannot be held legally responsible for errors in the contents of this magazine or for any loss however arising from such errors, including loss resulting from negligence of our staff. Reliance placed upon the contents of this magazine is at readers’ own risk.

RCM&E | 7

SWITCHON

Get in touch...

kcrozier@mortons.co.uk

JOIN THE CHEDWORTH CLUB The Chedworth RC Flying Club, situated between Cirencester and Northleach in Gloucestershire, is looking for new members.

This long-established club operates from a tarmac runway, 90m by 30m, in private farmland with beautiful Cotswold views.

Landing on grass is not available. We have our own locked car park. The club currently has a flying site permit up to 1500 feet for models up to 25kg. We can fly every day of the week except for about seven days during the winter. We are affiliated to the British Model Flying Association, so BMFA

membership is a mandatory requirement.

All styles of radio-controlled models are flown at Chedworth, fixed and rotary wing. The proximity of trees and a public footpath across either ends of the runway tends to naturally limit the size of models that may be flown, and gas turbines are limited to a maximum of 120 Newtons. We abide by the noise code so piston engines do require adequate silencing.

The 2023 membership fee is just £65 and there is no joining fee. We do not hold regular club meetings, but we do try and have a few flying events at the airfield each year.

Further information and a contact form is available at our website https://www. chedworth-rcfc.org.uk or email secretary.chedworthflyingclub@gmail.com Harry Curzon, Treasurer, Chedworth RC Flying Club

WEALDEN HANKY PLANKIES KEEP COMING! At the end of the 2022 season the December issue of RCM&E included plans for the Hanky Planky, with a challenge to make several as a club build. The Wealden club, led by our Secretary Bob Hart, took up the challenge as a winter project and the membership rallied to this call.

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A number were rapidly built and in the March edition of RCM&E (p.49) a picture was published showing that seven had been completed. Since then the numbers have more than doubled and we now have over 14 built. This project has really fired up the membership and while the Planky is only a small aircraft compared to the usual more complex aircraft and helicopters in the club it has proved to be a very bonding exercise.

Another byproduct of the challenge is that several members were encouraged to build a model rather than assemble an ARTF. Now we are into the new flying season it’s time to fly and numerous pictures, some shown here, demonstrate the fact we can all interpret R/C model plans. All our Hanky Plankies fly very well and it has proven to be a lively machine with sensitive controls. The members have elected to use a variety of motors and LiPo batteries, most running 3S 2200mAh packs but many are also using 3S 1300mAh LiPos. Capt. Gregory J Cassar www.modelflying.co.uk | July 2023

INDIAN CANBERRA

BMFA FESTIVAL OF SCALE

The BMFA Scale Technical committee are pleased to announce a weekend ‘Festival of Scale’.

This relaxed event is aimed at all things scale. As well as fixed wing aircraft we are looking forward to hosting scale gliders and helicopters.

Models will not just be radio controlled but control line and free flight models are welcome too, weather permitting.

Unfortunately, we cannot accommodate turbines due to adjacent crops.

On the flight line slots will be organised to make sure that everybody gets some airtime. We are planning to hold some technique workshops too.

An online booking system has been set up and it can be accessed via: https:// scale.bmfa. org/2023-festival-of-scale

Chester Model Centre received an unexpected customer enquiry all the way from Bangalore, South India.

Arun Swaminathan was looking for an elusive die-cast model to add to his collection in memory of his late Uncle, Wing Commander Padmanabha Gautam, a highly decorated Indian Air Force pilot who flew the English Electric Canberra during his distinguished career.

Paul Boyland, the owner of Chester Model Centre, says: “We’ve been running our shop in Chester for over 10 years, and we couldn’t do it without so much local support. Having said that, the modelling community is global and we were really happy to help Arun get his hands on the Corgi model of the Canberra that his Uncle Gautam had flown.”

Arun says:“I cannot tell you how grateful I am to you. This model means a lot to me especially as this English Electric Canberra has been etched in my heart after my Uncle Gautam was killed in a crash in 1972. My father always wanted to take me to Poona with my Uncle Gautam (see picture) so he could put me in the cockpit of every aircraft under his command.

Unfortunately, my uncle died before this trip happened. When I miss him I go and stand by the Canberra at the HAL Museum near my house in Bangalore. I am writing his biography and this model will feature as my most treasured model in my collection.”

Arun is hoping to make a trip to the UK in the future with a visit to Chester Model

Centre on the top of his list of places to see.

Paul says: “We are quite a traditional hobby shop and giving people a hands-on experience on the high street is really at the core of what we do.

We had been digital dinosaurs but we realise it’s important that we evolve as a retailer. We launched our website during the first lockdown (Spring 2020) and are now active on social media. We’ve been contacted by customers from Australia, America, France and Italy. The attention from across the globe has prompted us to think bigger.

We are currently planning to make international delivery available to our customers and hope to have this service up and running in the next few weeks. As a local independent shop this opens up a big market for us.”

The English Electric Canberra is a popular model and it is thanks to Wing Commander Gautam’s story that we can appreciate this incredible aircraft even more. You can learn more about his life and what makes the Canberra so special by visiting Chester Model Centre’s website: https://www. chestermodelcentre.com

AFTER SANTA CRUZ Our regular Portuguese correspondent Arnaldo Correia, who keeps us updated on scale projects being undertaken in Iberian countries, has sent in details of the latest seaplane project being built by his friend Mário Vilaça: “Please find attached a photo I received of Mário’s newest project. It’s a four engined flying boat with ‘a little under 3m’ wingspan. I think you’ll recognise it as a Martin JRM Mars, one of the two used for firefighting in July 2023 | www.modelflying.co.uk

Canada and the USA until a few years ago. It will be equipped with four HK Grumman Albatross power sets (motor/ESC/propeller), with a 4S battery (probably 5000mAh) being used as the power supply.

It will be a ‘quickie’, or a sports model if you prefer, so Mário is looking forward to having it flying this year.

After Santa Cruz (see Dec 22 and Jan 23 issues) it’s understandable he may want a simpler model! On the other hand, Mário being Mário, from a few feet away it should look lovely.”

RCM&E | 9

CUMUL Fancy trying your hand at a Discus Launch Glider? John Stennard builds a well thought out DLG kit from Kavan words & photos » John Stennard

Cumul is a star performer and looks attractive in the air.

T

here are two things to look at straight away: one is Kavan and the other is Cumul.

Franz Kavan started his kit and accessories firm in Germany in 1965 and the Kavan brand (www.kavanrc.com) is now handled by the Pelikan Daniel firm (www.pelikandaniel.com) based in the Czech Republic. In addition to his high-quality products, Franz Kavan is perhaps best remembered as the designer and manufacturer of one of the first successful R/C helicopters, which was introduced in 1972.

Kavan products are available from some retailers in the UK, and I purchased my model from Model Shop Leeds.

Now, as to the name Cumul, all I’ve been able to come up with here is that it’s an abbreviation of Cumulus which, to me, sounds more attractive.

DLG HERE WE COME

I’ve always had an interest in DLG gliders but they are lower down my enthusiasm list than aerobatic electrics and EDF, although I’ve

10 | RCM&E

www.modelflying.co.uk | July 2023

TESTING, TESTING | Discus launch glider

Kit comes in an attractive box. CNC cut balsa and ply parts are all excellent quality.

Semi-finished pod. 21 parts in total!

Two 6g servos are a snug fit.

Tail unit is easy to build and fits securely to the boom.

owned and flown several DLGs. Mine have been the type of model that I load in the car along with others, but not necessarily assuming I will fly it. Some of this reasoning comes from the fact that achieving successful flights with a DLG can be very dependent on weather conditions. So, the model will either get flown or stay in the car.

Having said that, I have always really enjoyed the challenges inherent in a DLG, both when launching one and in the quest for lift.

STARTING POINT

One thing I’ve never done is build my own DLG. My previous models have all been of the

July 2023 | www.modelflying.co.uk

minimal assembly type with ready covered wings etc. Finding myself without a DLG, and possibly some good flying weather ahead in 2023, I did a bit of hunting on the net and spotted the Cumul. This model is a bit different as it is a modern kit, with all mod cons.

However, I had to be patient and wait until there was a delivery of this glider from the Czech Republic. Model Shop Leeds were on the ball and emailed me as soon as they arrived, and a surprisingly small parcel was quickly and safely delivered.

The size of the box is dictated not by the carbon fibre (CF) tube boom but by the beautiful, full size rolled plan. All the balsa parts are equally impressive being of excellent RCM&E | 11

Completed wing framework is very strong.

This tiny 150mAh NiMH pack is just the right size.

quality and accurately CNC cut. The many parts are separated and stowed in six separate bags. A curved and slotted length of balsa has you guessing, until you consult the plan and find that it’s a rib jig that can used in turn for assembling the two wing halves. Many of the parts interlock to ensure a speedy and accurate build. The ribs, for example, have jig tabs allowing for both for the undercambered build and to include washout. Non balsa parts include a CF tube main wing spar and beech dowel leading edges, plus the CF tube boom. A lightweight heatshrink covering is recommended. Although primarily intended as a DLG, a tow hook is also provided.

A 27-page A5 manual is included, which does make for a small font - time to put on the reading glasses! It also includes several pages with colour photos to help with

construction. Kavan mention that this model is ‘maybe not an ideal first model for a newcomer without any previous experience’. The model’s design certainly has a high performance feel about it.

So, with an excellent plan, comprehensive instructions and set of CNC cut parts all I really need do here is to highlight some points in the construction and finishing, and then report on flying the Cumul.

ENJOY THE BUILD

Having read the instruction booklet and perused the plan I decided it made sense to build the model in the suggested stages. I confess I don’t always do that and sometimes I build a model in the order I fancy. Regarding adhesives, a selection of PVA, cyano (CA) and epoxy are required.

All-important discus finger grip feels just right.

The instructions start with the tail parts, which is a nice introduction to the assembly process and the kit parts. There’s nothing to report here but it gave me the opportunity to dry fit the tailplane and fin in place and get an idea of what the tail end of the model will look like.

The instructions move on to the fuselage pod. Your first thought might be, ‘A pod, that’s simple to build.’ But this pod involves 21 pre-cut parts! Using the precision cut parts the pod assembled easily and I could now see the available space for the receiver (Rx) and flight battery. The pod includes a hatch for access to the servos. The Rx can be positioned under the wing, where there is adequate room for a small or micro receiver and a quick check showed that a Spektrum AR 410 would fit easily. But I soon realised that I did not have an Rx battery pack that would fit in the pod in front of the servos. As I fly mainly electric powered models I rely on the BEC for power. However, I found a very small Rx battery pack on the Component Shop website.

It’s a 4.8v 150mAh NiMH of 1/3 AAA flat configuration. It only measures 10 x 14 x 43mm and weighs just 16.2g. When the servos were fitted I found that this pack would slide in past the servos so it can be removed for charging.

ON A WING AND A PRAYER

The wing build proved to be quite challenging, mainly because it uses a completely different technique to the type of construction I am used to. Checking things out I realised that the wing ribs have no markings on them and there are 21 ribs/riblets in each wing half. Comparing the sheets of ribs with the plan I was able to identify and mark all the ribs prior to construction. The trailing edge and the leading edge jigs have rib slots in them which matched up but the slots did not match up with the wing drawn on the plan. I was puzzled by this and an investigation showed that the plan was incorrect.

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www.modelflying.co.uk | July 2023

TESTING, TESTING | Discus launch glider

Pod access hatch is secured with a ply finger and a magnet.

DATAFILE

Name: Manufactured by: UK Stockist:

The wingspan is listed as 1096mm but in fact it’s 1010mm, according to the pre-cut balsa parts! This made the construction a slower process as the ribs/riblets, other than the tip rib, did not line up with those drawn on the plan.

As I mentioned the wing construction is unusual as one has to thread all the ribs and riblets onto the CF tube and carry on the construction from there using the slotted trailing edge and leading edge jig. It was

not a quick build, but it has resulted in a very strong wing.

The final addition before covering was to glue the discus launch CF tube in place. This is reinforced with glass matt.

My choice of heat shrink covering was dictated by what I had left over from my last model! I covered the wing in a transparent yellow film as I like to see the wing structure through the covering and I used transparent red on the tail surfaces and pod.

Part No: RRP: Wingspan: Length: All up weight: Wing section: Functions: Required to fly:

Cumul DLG Kavan Model Shop Leeds https://www. modelshopleeds.co.uk/ catalog/index.php KAV02.8023 £88.99 1096mm 880mm 180g YA0801 Rudder and elevator Small Rx, two 6g servos & Rx battery

Late January and a pre-test flight photo shows the attractive lines of the Cumul.

July 2023 | www.modelflying.co.uk

RCM&E | 13

“Cumul is easy to launch and is then responsive and smooth to pilot”

I was absolutely delighted with the way the Cumul performed.

FITTING OUT

Two 6g servos fitted the pre-cut balsa servo mount perfectly and ball type control rod connectors were fitted to the servo arms. An unusual feature is that in order to suit the position of the snakes and wire inners these fittings are positioned on the underside of the output arms. A brass threaded connector must be soldered to the servo end of the wire control runs. The control surface end uses a 90-degree bend or Z bend.

After the fin/rudder assembly and the tailplane/elevator had been covered and hinged using the covering film they were glued to the CF tail boom. The plastic snake outers can then be threaded through the boom and into the servo area of the pod. Connecting up Cumul shows off its construction through yellow transparent film.

the control runs is more fiddly rather than difficult but it’s important to make sure the servos are centred and the piano wire inners operate freely.

With the battery in place a C of G check showed that some nose weight was required.

I had to fit 20g of weight ahead of the battery to achieve the recommended position, which increased all up weight (AUW) to 200g. The instructions show 180g AUW. Test glides will show if the nose weight is required.

LET’S FLY

The instructions include a section on test flying and a detailed explanation of the discus launch technique. Once a level glide has been obtained you are ready for a discus launch. The

instructions recommend using a small change in rudder and elevator settings for the discus launch. This can be achieved using a ‘Flight Mode’ switch set up.

It’s 30th January, the sun is shining, it’s not too cold and there is a light wind. So it’s a promising day to try some test glides at my local farmer’s field, just five minutes away.

Only test glides of course, none of that discus stuff! The test glides were almost perfect, with the model being just a tad nose heavy. Elevator seemed a touch sensitive, so I put in some expo to calm this down.

Cumul looked great in the air and a nagging voice in my head kept alternating between ‘Go discus, go!’ and ‘No discus, no!’ Having discus launched before I decided that it had to be done and started with a shallow launch. This was encouraging, with the model showing no unforeseen tendencies. I quickly built up to steeper launches and they proved to be perfect. This is possibly the easiest DLG model I have ever launched. The longish grass was not conducive to fast pirouettes so I was never going to reach any great height. However, I was absolutely delighted with the way the Cumul performed. She came off the top of the climb cleanly and flies so smoothly. I went home a very happy man!

Subsequent flights were equally satisfying and with faster pirouettes and stronger throws I was achieving my best ever discus launch heights and flights.

PILOT’S NOTES

What a delightful model this is. I think the kit is good value and the building process is interesting. The finished result is a very attractive built-up model with not a scrap of foam in sight. The Cumul is easy to launch well and is then responsive and smooth to pilot. I’ve already had more satisfaction from this model than any of my previous DLGs.

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www.modelflying.co.uk | July 2023

HOOTS MON! Shaun Garrity buys a secondhand model and finds ‘…a mouse loose aboot this hoose’ words & photos » Shaun Garrity

G

eoff, a fellow club member, had decided he needed to unload some of his gliding fleet. So never one to miss a potential bargain I went round to see what was on offer.

After delving through the pile of gliders and kits in his workshop a deal was done. But just as I was leaving, I noticed a Graupner ARTF Kwik Fly 3 sitting up in the rafters. I’ve been after one of these for several years and, even better, it was for sale.

The fuselage came down first and other than a lot of dust and some slackened off covering film it looked in great condition. Grabbing the wing I noticed the rubber tyres looked

16 | RCM&E

like they had been subjected to a hard life on tarmac or concrete runways, with lots of pieces missing, but other than that the lower covering was in good condition. Turning the wing over told a different story, however. I noticed a red trim panel was lifted and on closer inspection, there it was - a mouse nest in the wing. Said mouse had obviously vacated casa Kwik Fly but it did me a favour as the price suddenly and significantly dropped.

Pulling out the nest cleared up the mystery of the wheels as lots of nibbled bits of tyre were scattered in the wing. Strangely, on removing the top covering film the mouse obviously

had delusions of grandeur, wanting to extend its property empire and had nibbled its way to the other wing tip, seemingly having a particular liking for the top spar and shear webbing.

The good news is the rodent vandalism can easily be repaired with an hour or two of effort and I’ll have the Kwik Fly 3 airworthy and back in the sky very soon. That is when I’ve located a very weird shaped fuel tank and a motor mount with an extremely odd bolt pattern.

Oh, and found a suitable two stroke motor!

I think Geoff’s next purchase should be a shed cat to protect his remaining model fleet.

www.modelflying.co.uk | July 2023

RETRO RAMBLINGS | Column

Currently a ‘Not So Kwik Fly 3’, but it won’t take long to fix Mickey’s vandalism and have this classic airframe back in the air.

1

1. Rodent vandalism has re-profiled this tyre.

3

2

2. And then I found the nest…

3. It didn’t look too bad when I removed the film on this side of the wing with just one rib nibbled.

4

5

4. But the other side had some major tooth inflicted modification to the spars and shear webbing.

5. Mickey was obviously keen on some significant remodelling in his new house, attacking these ribs as well.

July 2023 | www.modelflying.co.uk

RCM&E | 17

MORE WILLARD WONDERS

Deciding to have a bit of a clear out myself, I started going through all my models employing a simple rule: if I hadn’t flown it in the past five years or so then it was time to move it on.

I came across what I thought was a McCutchen wing. Also known as a Charybdis (the name of a whirlpool between Italy and Sicily), this strange looking flying plank is essentially a single blade free flight helicopter; the only moving part is the engine. The original design by Charles McCutchen was published in July 1954 Aeromodeller and was no doubt inspired by Charles watching a sycamore seed ‘wing’ its way to the ground.

A quick look at the accompanying plan will clear things up but essentially Charles described it as: ‘A wing and motor on opposite ends of a boom with a weight on the end of a stick to put the Centre of Gravity ahead of the leading edge and to ensure that the moment of inertia is largest about the axis perpendicular to the wing.

In flight the wing sweeps out a cone and the balance arm, owing to centrifugal force, is nearly horizontal. When the engine is running the

gyroscopic precession of the propeller raises the balance arm above the horizontal position, giving the wing a positive angle of attack. The thrust from the engine keeps the whole machine rotating and it climbs. When the engine stops the angle of the wing and balance arm falls below the horizontal and the machine autorotates down to the ground.’

Charles found that not all configurations were stable but fortunately due to a good understanding of aerodynamics and lots of experimentation he cracked it. If you want chapter and verse on the theory of this odd ball flying machine, I would suggest tracking down a copy of the original article.

Anyway, my particular wing had been given to me a number of years ago and I always assumed it was a McCutchen. But on researching Ken Willard designs last month I came across the Rotoriser and realised my Charybdis was actually Ken’s version. I would love to be able to fly it at our field, but free flight isn’t allowed as it’s a public space. If you ever attended the BMFA Nationals at Barkston Heath, it was common to see a number of these whirling dervishes heading skyward in the evening ‘chuck and duck’ sessions. I have seen a You Tube video of a modeller who’s made

As can be seen from the plan it’s very simple to construct.

The McCutchen Wing made its debut in Aeromodeller. True ‘out of the box’ thinking for this unique model.

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an electric powered Charybdis, with an R/C throttle to enable a modicum of controllability.

Maybe that’s the future and it will certainly sort out any carburation and fuel feed issues.

This one I’m keeping, so the rule breaking had already started.

Another model I extricated was the Das Ghosten Flugboot. I covered it in RCM&E, December 2016. Originally designed back in 1970 by Derek Walton, this flying boat was novel for a number of reasons and used Galloping Ghost with a home-made actuator.

Again, whilst looking through Ken’s back catalogue, I came across his Shearwater design from 1967 and it’s not hard to see where Derek got his inspiration from for his flying boat.

BUMBLE-B

Back in the late 1960s and early 1970s there was a range of quick build kits designed by David Boddington for single or two channel.

They featured a moulded 40” injection moulded foam wing that was common to the range: Kestrel, Nipper, Flapper, Planet and Bumble-B. These kits were manufactured and distributed by Micro-Mold.

McCutchen inspired Ken Willard Rotoriser.

Ken Willard’s version of McCutchen’s whirling dervish.

www.modelflying.co.uk | July 2023

RETRO RAMBLINGS | Column

2

1 All but one had traditional balsa/ply fuselages, with the Kestrel featuring a moulded ABS fuselage. These kits were low cost and provided an easy way to get skyward as the wing was essentially ready finished. In fact, it didn’t even need covering.

The Kestrel glider was an updated version of a traditionally constructed model designed previously by Dave. Nipper was essentially a Ghost Rider look alike, while Flapper was clearly influenced by the Barnstormer, Planet a sort of Craftsman and the Bumble-B a midwing 1/2A racer similar to the Ghost Racer and Emperor. The recommended power range was 0.049 to 0.09 cu.in., the exception being 0.020 to 0.049 for a power pod option on the Kestrel. Cox TD’s or even the humble Babe Bee would have them zipping around the sky.

Last year I managed to pick up a Kestrel kit. I had been after one for a long while as this little model caused me some serious grief many years ago and there was a score to settle…

I’ll explain. I’d managed to dislocate my shoulder and after a month of recuperation I went flying. On arriving at the field, and being the first there, I set up the model, fired up the little Cox and checked the radio – all good. With virtually no wind that day I gave it a hefty lob skyward. This is where things went sideways quickly because my arm decided it wanted to try to follow the Kestrel and dislocated again. Having no throttle on the Cox the next five minutes was the least enjoyable flight I’ve ever experienced and, adding insult to injury, the fuselage broke on landing - a salutary lesson in why not to fly solo.

Anyway, many years on I now have the opportunity to enjoy what the plane was designed to do. Unfortunately, I dislocated the same shoulder a month ago after a fall.

Maybe this is a cursed model that I should forget about!

I have a request. Does anybody have a Bumble-B kit sat in the loft that will never get finished. The reason I’m asking is I want to build one. I’ve even called Dave’s son, Andrew to see if he had the plan, as I have a few of the Micro-Mold wings, but unfortunately he hasn’t. So, if you have one, please contact me so I can arrange to get a copy.

July 2023 | www.modelflying.co.uk

3 5

4 1/2: Comparing plans, you can see Flugboot was a very similar design to the earlier Shearwater, which was an uncomplicated flying boat. Ken Willard designed a number of these aquatic wonders.

3: I’ve had a lot of fun with my Das Ghosten Flugboot.

4: I have a few in the build pile. The one-piece injection moulded wing seen in the foreground was common to the range, 5: Micro Mold had a vast range of modelling related products and produced some interesting kits besides the Bumble-B that I’m after. The Lark helicopter introduced many modellers to rotary flight.

RCM&E | 19

MFA were one of the UK’s first suppliers of electric powered aircraft.

MFA

These kits will be built. But they will not be fitted with brushed motors and NiCads!

MFA Olympus belt drive units were a great way to eek out extra usable power from your brushed motors. Also shown are noise suppression capacitors and a simple on-off switch that could be servo operated or coupled to the elevator so up turned it on and down turned it off.

20 | RCM&E

Boat modellers were also accommodated for in MFA’s wide product range.

Model Flight Accessories. If you’re of a certain age you can’t fail to have come across them as a modeller. Established back in 1967 and based in Deal, Kent they provided a wide range of products for modellers and were one of the first UK companies to get involved in electric flight, carrying a wide range of brushed motors, gear boxes, pulleys, gears, shafts, motor mounts etc. along with motors and accessories for the boat modeller.

Another product line was their aircraft and boats kits, with a number of planes designed specifically for electric power. The Spearfish, Piranha and Fairey Fantome boat kits featured glass fibre hulls, very complete hardware packs and exceptionally quick assembly, with the option of IC or electric power. The early electric only planes were called Hummingbird, Magicfly and Britten Norman Islander Twin.

The Hummingbird, to be fair, struggled in the air with its heavy NiCad payload and direct drive motor. But the Magicfly featured MFA’s Olympus gearbox, which was a belt driven 2.3:1 unit. With a standard Speed 550/600 motor it could easily turn a 10 x 6 to 11 x 6 prop and knocked out a lot of useable draught. In its day the Magicfly was one of the better aerobatic electric models. The mistake a number of modellers made was to choose the foam wing version for build speed over the traditionally constructed wing for lightness. Back then every gram of weight saved improved flight

performance as the available power from these very heavy electric set ups was pitiful - and that’s being kind. Using a gearbox was a way to squeeze out the best performance. ESCs were not required as you either wanted full power or zilch, so a servo operated switch would suffice; or if you were feeling particularly flush a relay operated switch. The Olympus drive unit was also sold adapted for model cars and boats.

I have all three of these kits in the build pile but not being a masochist I will be using brushless motors and LiPo’s. However, I’m certain that replacing the original NiCad pack with an equivalent lighter LiPo, a suitable ESC and modern mini servos, it would still fly well on the original motor and gearbox set up.

From memory other popular kits were Golden Eagle, High Sierra gliders and the everpopular Yamamoto trainer.

HUGHES 500D

My first foray into R/C helicopters was with an early Morley Bell 47 kit. No gyro, fixed pitch and an unskilled pilot (me) equated to frequent re-kitting, so it was side-lined.

A few years later I came across MFA’s Hughes 500D and at the time Magnum P.I. was a popular TV show that starred (besides Tom Selleck’s huge moustache) a Hughes 500D, resplendent in a black, yellow and orange colour (this was a factory standard colour, not a custom job for the show). I instantly got carried away and bought one (the 500D, not

www.modelflying.co.uk | July 2023