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radio control models and electronics

Turboprop Pilatus VOL.66 NO.9 SEPTEMBER 2023

d lflyi g k www.modelflying.co.uk

ONE OF THE MANY STARS AT WESTON PARK

One model comp

CLUB FUN WITH W PHOENIX GLIDERS

Push me pull you

REMEMBERING LINEAR SERVOS

Swing g wing g B-1

LARGE LANCER REVIEWED

PLUS II F5J FINE TUNING - THERMAL SOARER SET UP II CHIPPING AWAY - DEHAVILLAND SCALE BUILD

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

W

elcome to the September 2023 issue of RCM&E. In late spring I received an unexpected birthday gif t in the form of some pristine £10 notes. It wasn’t a vast amount but was welcome nonetheless, especially as I have been making good headway on cleaning up my workshop ready for, I hope, some good old-fashioned balsa bashing come autumn and winter. I instantly knew what I would spend it on and that was a label printer so that I could neatly mark up the contents of the multitude of small boxes that had piled high during my recent clearing out sessions.

A bit of research online, including visiting that famous internet shopping company, whittled down my options to two well-known makes of label printers, with one product coming out marginally better in reviews than the other. As they were very close in price, regardless of the shops I checked out, it basically came down to one being less wasteful when cutting of f each label than its competitor. Replacement label cartridges also seemed to be more prevalent in local shops than for the other type.

So, I ventured to a nearby newsagent, part of a nationwide company that does sterling work selling this and other Mortons Media publications, handed over my readies and was soon back in my workshop happily printing copious numbers of labels. It will also come in very handy when printing my operator ID number for attaching to any new models!

Roll on just a couple of days and a much-needed holiday in Cornwall beckoned. So, along with my better half, we nipped round to the local supermarket – the one with the magnetic (to me!) centre aisles that I mentioned a couple of issues ago – to stock up on a few essentials. Of course, I couldn’t resist taking a detour down said centre aisles looking for any new bargains and was cock-a-hoop to discover a box of print cartridges for my shiny new printer. At well under half the normal price, I had to resist buying too many – af ter all how many labels does any shed-dweller really need – and so I finally settled on two packs, which should keep me going for a bit.

A few days later, af ter dodging the rain showers all around the River Tamar, we were back in the same supermarket again, this time topping up the cupboards at home with a few things whilst we awaited our weekly grocery delivery from a rival store. (Home delivery is best, my wife reckons, to stop me picking up things that we – make that I - don’t really need!)

4 | RCM&E

Anyway, I had to take a sneaky look at down the middle of the shop and that was my downfall. There, staring at me, were a neat row of the same label printers, but these were going for less than half the recommended retail price that I had paid just over a week before. My gast was well and truly flabbered!

Oh, well. I’ve had a good run I suppose when shopping in there for bargains, so perhaps it was time for my luck to run out. I doubt if it will put me of f though!

Time now to take a brief look at what we have lined up for you in the October issue of RCM&E, starting with our regular columns.

In his latest Retro Ramblings, Shaun Garrity finds himself unfazed as three predictions in his last column fail to materialise, before going on to discuss the pros and cons of linear servos. In Make It Scale, Danny Fenton continues with his deHavilland Chipmunk build using the Jerry Bates plan.

Then it’s over to Graham Ashby and Kick The Tyres in which Graham broaches the thorny subject of accident-prone pilots, then lightens the mood with a ritual sacrifice For this month’s centre-fold Pro-Plan, Tony Nijhuis returns with the third EDF jet in his latest series of TN Mini Jets. The aircraf t modelled by Tony this time is the F9F Cougar.

Our feature articles start with Part 2 of Creating Your Own Model during which Martin Hardy details the design and build of his 90-inch span electric powered Avro Shackleton. Next we have the concluding part of another two-part feature, The Road To Bulgaria, where Alex Maxfield continues his preparations for participating at the F5J World Championships in Bulgaria later this year. Concluding this month’s features, Mike and Al Freeman team up to tour the stands and roam the pits at this year’s Weston Park Airshow International.

On test this month David Ashby test flies a mighty B1-B bomber and discovers that XFly’s new swing-wing jet is a bit of a beast, albeit a friendly one. Finally, a one-model gliding comp is a fun way to spend a flying session, as I found out when assembling my club’s chosen soarer, the Volantex Phoenix S 1600.

I hope you enjoy reading it all.

Happy Flying!

www.modelflying.co.uk | September 2023

CONTENTS

RADIO CONTROL MODELS & ELECTRONICS I VOLUME 66 ISSUE 09

86

ONTHECOVER

Photo: Mike & Al Freeman One of the stars of this year’s Weston Park show, Mark Leavesley’s Pilatus PC-21 Turboprop beats up the strip with smoke on. This 2.68m span fully composite model is manufactured by Tomahawk Aviation and was supplied

by Az Aerosports. She is powered by a JetCat SPT10-RX Turboprop engine.

Mark says she is a pleasure to fly; he certainly put on a smashing display.

Reviews

10 B-1B LANCER

As David Ashby discovers, XFly’s new swing-wing jet is a bit of a beast, albeit a friendly one

64 PHOENIX S 1600

A one-model gliding comp is a fun way to spend a flying session.

Kevin Crozier assembles his club’s chosen soarer

64 Regulars 8

SWITCH ON

Our latest round up of model flying news.

36 COUNTERPOINT

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

72 PILOTS’ PICTORIAL

Send us a picture of a new or favourite model and it could appear in our regular readers’ models gallery

78 GOING PLACES

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

10

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 October ‘23 issue of RCM&E

98 PARTING SHOT

We close this issue with Bill Cousins photographs of Dave Keen’s 28% scale Vailly Aviation Fw190 on its LMA over 25kg certification flight

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www.modelflying.co.uk | September 2023

28 22

Features

28 CREATING YOUR OWN MODEL

Martin Hardy details the design and build of his 90-inch span Avro Shackleton Mk.2

62 SUBSCRIBE…

... and receive Luftwaffe Fighters & Supermarine Secret Projects FREE!

Columns

16 RETRO RAMBLINGS

Shaun Garrity isn’t fazed as three predictions in his last column fail to materialise

38 THE ROAD TO BULGARIA

22 MAKE IT SCALE

86 WESTON PARK 2023

80 KICK THE TYRES

Alex Maxfield continues his preparations for participating at the F5J World Championships

Danny Fenton continues with his Chipmunk build using the Jerry Bates plan

Mike and Al Freeman team up to tour the stands and roam the pits at this year’s Weston Park Airshow International

38

Graham Ashby broaches the thorny subject of accident-prone pilots then lightens the mood with a ritual sacrifice

48

16 free pro-plan

48 F9F COUGAR

Tony Nijhuis returns with the third EDF jet in his latest series of TN 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.

September 2023 | www.modelflying.co.uk

RCM&E | 7

SWITCHON

Get in touch...

kcrozier@mortons.co.uk

DEPERDUSSIN DEVELOPMENTS Following his article on his 1911 Deperdussin in the July issue of RCM&E, Ian Turney-White has been busy developing his impressive 3.8 metre span Edwardian monoplane. His main efforts have centred around replacing the 342cc Westlake drone engine for something a bit more powerful. Here’s what Ian has told us so far over a series of emails: ‘I decided to borrow, for now, the JPX 425 cc motor, its reduction drive and the 56” x 26 “ prop from my Hanriot biplane (I’m making enquiries about obtaining another JPX.) I removed the JPX’s ‘bell’ mount and replaced it with a flat plate mount to reduce the engine’s length and the effect on the Centre of Gravity.

I am also making a new larger volume steel silencer that will just fit in the lower fuselage cut-out.

When I flew the Deperdussin with the Westlake it was marginal on power. But with the JPX running nicely at around 4600 rpm it’s running at its peak power of 26 horsepower, which will allow me to do so much more when flying it and also

8 | RCM&E

have a useful reserve of power.’

‘I fitted the JPX plus reduction drive and test run it. There’s at least a third or more power. I had to move all the batteries rearward etc.

I hope to test fly it when my inspector gets back from his holidays next Sunday.’

‘I finally got round to flying it with the new engine last week. The larger engine flew it so much better - more power, much better climb rate and I was able to fly the model with the engine throttled back.

I had moved the radio and start batteries as far back as I could, plus I added about 12 ounces to the tail end to move the Centre of Gravity rearwards. I ended up adding a few ounces more, which allowed me to get rid of most of the up trim and I felt the model becoming much more responsive.

I had four flights but on the last flight I had just turned the model downwind over the wheat field that surrounds the strip (which had grown considerably whilst I was waiting to be able to fly the model) when the engine just stopped. There was no chance of getting back to the strip so I could only level the wings and try and flare it onto the crop. Wheat is not very forgiving, and the model sadly suffered a lot of damage to the front fuselage. The pilot’s body and upper legs were smashed to bits but I but have since rebuilt him and he’s now fit to fly again.

It’s Sod’s Law that the engine stopped just where it did. The only fault I could find was that the sensor/lead was inoperable; with a new sensor/ lead the ignition unit was sparking away merrily. With hindsight I wished I had

flown it somewhere else with more useable room but it’s always easy to say that.’

‘Besides repairing the Deperdussin, I will advertise in the British Microlight Association’s magazine for a JPX motor, plus I have a French friend who is a modeller and an Air France pilot whom I may ask for some help in tracking down one of these motors (they were made in France.)

Plus, if I can get a JPX, I will make an improved reduction drive system that uses a new type of drive belt which, by all accounts, is very long lasting and has minimal vibration.

Then the engine/reduction drive unit I borrowed will be fitted back in the Hanriot and extensively tested.

The Deperdussin rebuild will give me the opportunity to move the elevator and rudder servos rearwards, minimising tail weight. Plus, it will have a slightly shorter nose, again to help with the CG. I will also fit the alloy disc that has the magnet (for the ignition) fitted to it onto the protruding rear end of the crankshaft, plus the sensor/lead where it will be more protected from any possible damage.’

Thanks for all the updates, Ian. We are sorry to learn of the damage sustained by the Deperdussin but we are sure you will have her back in the air soon. Please continue to keep us informed.

www.modelflying.co.uk | September 2023

PAYLOAD CHALLENGE CORRECTION With reference to her BMFA Payload Challenge report in Switch On in the last issue, BMFA Outreach Director, Helen Jones has asked us to publish the following correction:

“It has come to light that when I wrote the report for you that I hadn’t got an up-to-date results sheet. Therefore, it meant that I have given incorrect information regarding which

team won the Distance challenge. It was actually I School Chenmai.”

Many thanks for letting us know, Helen. And congratulations I School Chenmai.

TWICESIZECLASSICS Over now to our resident shed based correspondent, Dave Goodenough: I’d long wanted to recreate the models from my aeromodelling formative years and once I had lots of free time available, I decided to get on with it - but with a twist…

I built the twice-size Keil Kraft ‘Invader’ (featured in a previous article in RCM&E) as a ‘proof of concept’ and with that model being so successful I began to annotate the two times enlarged plans for both the Keil Kraft ‘Topper’ and Veron ‘Verosonic. The Topper was built and modified exactly as the ‘Invader’, with a split wing pivoting on the tubular wing joiner and operating as a ‘Twisteron’, or ‘Pitcheron’ via two fuselage mounted metal gear servos, giving a very positive form of control.

A 300W outrunner in the nose and a flat-bottomed aerofoil gives the model both flat field and slope practicality. As with the Invader, the two-metre wingspan Topper has proven to be a very able model, being easy to control and a pleasure to fly.

The Verosonic was a different kettle of fish, as the swept-back wing would be very difficult to modify for ‘Twisteron’ control. At some 2.4m span the wing structure was adapted for a flat-bottomed aerofoil, with aileron control and joined using Graupner wing blades,

September 2023 | www.modelflying.co.uk

which are slim but very strong - as I found later! The tailplane was modified for elevattors and secured with a bolt-on fin. No rudder iss used as this is an Aileron/Elevator/Motor model, despite its size. Having one spare, I fitted a 500W outrunner up front, to allow for f slope and field use. Despite a club worthy telling me that the Verosonic was ‘too heavyy and didn’t have enough power’, the model simply ignored him and flew just as well as the original 1949 Phil Smith confection was designed to do. It does fly with a distinct nose-down ‘sit’ but that may be my fault as I might have got the wing angle of attack a bit ‘off’. It looks very good in the air though, fighter-like on a fast and close-in slope pass! s!

I was taking a chance by committing so much time and a small grove of balsa and bass wood to the project, but the result is three very flyable and most enjoyable mod dels that are far removed from ‘the usual suspeccts’ on the field and slope.

The Verosonic proved its innate strength when I mistakenly attacked a drystone wall with it on an extended approach. The outer section of the right wing was smashed, right up to the main spar, yet the bass spar didn’t break, saving the main structure and making the rebuild simple. I won’t do it again, promise!

RCM&E | 9

B-1B

LANCER As David Ashby discovers, XFly’s new swing-wing jet is a bit of a beast, albeit a friendly one Words & photos » David Ashby

W

ell, this is a seriously impressive drop of ready-to-fly R/C aeroplane.

You’re looking at a B1-B with twin 70mm EDF units, bespoke CNC machined undercarriage, an onboard stabiliser, eight navigation and landing lights and - yep - a swing-wing mechanism that pushes the span out from 1040mm to 1776mm (70”). It’s a bit of a beast.

But then, so is the real thing. If you’ve ever seen a ‘Bone’ (as it’s affectionately known, B1 - Bone) fly past then you’ll know what I mean. For sheer presence, noise and downright impressiveness it’s right up there with the Vulcan and B-52.

There’s insufficient space to relate the type’s history (do look it up, it’s interesting), suffice to say that the prototype first flew in 1974, it’s capable of mach 1.25 (around 950mph) at altitude, the USAF ordered 100 and, as of 2021, the remaining 45 are planned to retire by 2036.

Which, incidentally, will be before the B-52 that it was designed to replace.

10 | RCM&E

BIG BIRD

Anyhow, let’s talk about the miniature. Has anyone modelled the B1-B before? The challenges are obvious, which is probably why I don’t recall seeing one. As you’d expect, this one is moulded from EPO foam and the finish is excellent. While it’s certainly large, both wings, the nose cone and rear fuselage section can be removed for convenient transportation if necessary, although my large estate car just about manages to swallow it up in one piece. Like some other XFly models the foam packaging can be used to protect the fuselage and wings for storage or transport should you wish.

A detailed instruction book guides the assembly sequence and glue isn’t required.

From a quick glance you’d assume that the process is a 30-minute job but it’s wise to prepare a large space and take your time.

There’s nothing difficult here but a methodical approach and a good read of the booklet pays

dividends. Oh, make a cuppa and sit down to watch the assembly and set-up video by the US distributor, Banana Hobby (search: Ultimate Guide: Setting up the XFly B-1B Lancer). I say that because the video, while very helpful also reinforces the importance of a few unconventional yet essential ‘need to knows’.

ASSEMBLY

A sticker on the foam packaging reminds you not to connect the flaps until the model is powered up. In this way the deflections can be adjusted while avoiding the risk of servo damage. I followed this advice but found that one of my flap servos was lifeless after buzzing noisily for a few seconds during the first power up. It was easy to swap out with an identical spare that I was fortunate to have lying around.

You’ll be impressed with the all-moving stabiliser’s rigidity and the ease with which the stab halves are aligned thanks to the threaded holes in the joiner rod to which the retention

www.modelflying.co.uk | September 2023

TESTING, TESTING | EDF scale jet

“A detailed instruction book guides the assembly sequence and glue isn’t required”

bolts screw. I think it’s sensible to apply thread-lock to the elevator servo quick link grubscrew while you’re at it.

There’s a substantial piece of hard wood running across the fuselage shoulder with swing wing mechanisms firmly fixed at either end. A single 25g digital metal gear servo does the pulling and pushing while nicely machined metal hinge assemblies and drop-in hinge pins secure the wings in a reassuring manner. I used a little tape to make sure the servo lead connectors were tucked away and didn’t foul the mechanism.

A large hatch cover reveals a generous sized battery bay while a small cover on the underside, magnetically retained, hides the combined gyro (stabiliser) and mixer board.

All servo leads converge in the battery bay where there’s plenty of room for a receiver too. The leads are marked, except one, a two-strand black/white lead and that’s for the ESC.

September 2023 | www.modelflying.co.uk

RCM&E | 11

“Keep the rates at 100% and avoid the urge to add expo and trim the model in flight” Perhaps it’s no surprise, given the nature of the machine, but the main takeaway from the video is that the on-board stabiliser plays a far greater role than those you may have encountered in the past. It’s not switchable (on/ off) in flight, although a small switch on the unit itself deactivates it - and deactivate it you must before the control surfaces are centered during assembly.

Another unusual feature: on the ground the control surface movement is slowish and the surfaces don’t self centre when the gyro is on. It seems strange but you’ve got to go along with it and trust the gyro. That gyro is king.

In testing I noticed that the flaps dropped a couple of millimetres when the wing sweeps back. It’s a programmed response and my guess is that it’s to camber the wing and provide a little extra lift as the shape changes in flight.

PRE-FLIGHT

The manual and the video stress the awareness of a few fundamentals. Firstly, the rates and trim mustn’t be altered. Keep the rates at 100% and avoid the urge to add exponential and trim the model in flight. Rudder is the only exception to allow adjustments to nose leg steering sensitivity.

12 | RCM&E

If you power the model when the gear is up then nose-leg steering is unavailable after the gear comes down, so just remember to cycle the power again after the gear is down.

Let’s talk about the C of G. You won’t be surprised if I tell you that the good ol’ C of G has come up for discussion more than a few times among early adopters in the online forums.

The C of G moves rearwards when the wings go back and that’s going to have some effect on the model’s stability and flying feel. The full-size machine pumped fuel between its wing and fuselage tanks in order to maintain equilibrium but until someone comes up with a way of shifting the LiPo battery in flight the gyro does all the work.

XFly’s suggested C of G is 48mm behind the leading edge measured at the wing root.

Banana’s video strongly suggests 81mm so this is what I’ve used and with hindsight I’m very glad I have.

FIRST FLIGHTS

I’ve flown many different model types over the years, so only very occasionally will something come along where I feel a little nervous. You won’t be surprised when I say that this was one of those. I had a healthy 12mph breeze coming straight down the strip for the first few flights.

It’s something I prefer for new EDF jets anyway as they sometimes need a bit of encouragement unsticking, or at least until I can suss out their take off traits. Such was the case here; the model accelerated to a respectable pace, but a little elevator wasn’t encouraging it to unstick. As the end of the strip approached, I had a choice of aborting or holding in a bucket load of elevator and hoping for the best. I did the latter and it leapt up with a few feet to spare.

For the second take-off I asked a helper to hold the tail, then give it a little shove as I throttled up. But that had little effect. Again, as the end of the strip approached, a lorry load of elevator saved the day. Dropping flaps a couple of millimetres did the trick for take-off number three and she was up in half the length.

There’s no mention of control surface deflection measurements in the manual so while it seems counter-intuitive, as I say, you just have to let the gyro do its thing. I left the wings out for the first flight and it flew very nicely with a positive, predictable feel.

It cruised nicely at around 60% throttle, low passes felt comfortable and, at full throttle, there was plenty of power in reserve if needed.

My first landing wasn’t the prettiest. I let it sink a bit too much on finals and although

www.modelflying.co.uk | September 2023

TESTING, TESTING | EDF scale jet

It’s not the first swing wing ready-to-fly EDF jet, although it must be the largest.

This digital metal gear 13g servo shifts the all-moving horizontal stabiliser.

A simple mechanism closes the nose leg doors.

Above: All retracts are reassuringly robust.

Left: Main retracts are beautifully done.

some power extended the glide path it touched down a bit heavier than I would have liked. No damage though. The first flight lasted 3.5 mins, the battery checker reporting my (800g) 50C 6S 5000mAh LiPo at 20% afterwards.

With a bit of height for comfort I retracted the wings when flying into wind during the second flight. The model started pitching down so, remembering the manual’s ‘no trim’ rule, only elevator would hold it level. Roll sensitivity increases when the wings are back, but the overriding impression was the need to keep the nose up. I felt relieved I’d set the C of G at 81mm as I hung on elevator far more than I really wanted to. Mindful of the need to keep the speed up and prevent a stall (gyro or not), high, wide manoeuvres were best in this configuration, especially as the nose has a tendency to dig in through tighter turns.

Keeping things big and smooth is best; it looks far more ‘scale’ too.

The gyro feels like a heading-hold unit and works hard to blend the variations in pitch that the swing wing creates. It’s not perfect but I think it does well given the task. Loops and rolls are possible and the videos are out there, but why would you? This one looks ridiculous the wrong way up.

The second landing was a happy event.

September 2023 | www.modelflying.co.uk

Here’s the clever bit. This combined stabiliser/mixer unit smooths out the flight wrinkles and helps the model manage the C of G alteration when the wings move.

A single 25g servo drives the swing-wing mechanism. Note the hard wood bearer and machined steel bracket and hinge pin.

Just like the full size this is an imposing beast.

RCM&E | 13

DATAFILE Name: Model type: Manufactured by: UK distributor: RRP: Wingspan: Fuselage length: All-up weight: Wing area: Wing loading: Power system:

Connector type: Functions (servos):

Required to fly:

Rates, expo and trim should be left alone. The gyro does all that.

B-1B Lancer Semi scale EDF jet XFly-Model CML Distribution cmldistribution.co.uk £749.99 1776mm (70”) - 1140mm (45”) 1920mm (76.8”) 5000g (11lbs) 573 sq.in.

130g/dm2 2 x 70mm 12-blade EDF units, 2 x 3060 2000kV motors, 2 x 80A ESC, 6S 5000-7000mAh LiPo XT90 Ailerons (2), flaps (2), elevator (1), rudder (1), wing sweep (1), main U/C gear doors (2) 6S 5000-7000mAh LiPo battery, receiver

I nearly ran out of runway during the first take-off before appreciating that a little flap helps it unstick.

Twin 80A ESCs receive some cooling airflow on the underside.

With the wings fully extended again I dropped flaps to the 10mm maximum suggested in the video. She dumped some speed and greased in comfortably, the small wheels untroubled by the short grass strip.

FRIENDLY BIRD

A methodical approach to assembly and flight prep is required here. This isn’t a model you can screw together without a second glance at the manual. Take your time, do your research, get the C of G back to 81mm (for your first few flights at least) and trust the gyro.

Battery bay is large which is just as well because some LiPo battery shifting is required. I flew with a C of G at 81mm compared to the 48mm in the manual.

This one was always going to present a number of challenges to the developers at XFly, not least in the C of G department, but the result of their efforts is very impressive.

Whether it’s for you will depend on your budget and flying field.

It needs a good short grass or tarmac strip and a big flying space, especially one that provides the room to settle it down during the landing circuit and approach. It’s a friendly beast then, a machine for experienced pilots, but it’s a gentle giant, one that looks and sounds fabulous.

Sight and sound.

Low passes are terrific.

Only in strong sunshine did I realise that the cockpit glazing masks an interior.

14 | RCM&E

www.modelflying.co.uk | September 2023

TESTING, TESTING | EDF scale jet

Although it’s nearly two metres long the nose and rear fuselage section can be quickly removed for transport.

“…it’s a gentle giant, one that looks and sounds fabulous” September 2023 | www.modelflying.co.uk

It’s well behaved when the speed drops. The flaps slow it down nicely.

XFly’s Lancer is certainly a head turner!

RCM&E | 15

Kwik Fly 3 is back in a respectable state.

For black trim I used a new (to me) heatshrink covering from Ripmax called AERO Film. I am very pleased with the results. It is unusual in that it has no backing sheet to remove.

SHAUN’S CRYSTAL BALL BREAKS! Shaun Garrity isn’t fazed as three predictions in his last column fail to materialise

L

ast column I made a few predictions that the mystery item was going to prove challenging, my Kwik Fly 3 would only take a few hours to repair the mouse vandalism, and someone would have a plan or kit for the DB Bumble-B. Well, I was very wrong.

On the upside I’ve probably had the best ever response to a mystery item and everybody was correct. It was a combustion chamber from a WW2 V2 ballistic missile on display at Cosford museum.

V2

The V2 (project name Aggregat A-4) was the world’s first long range, liquid propellant rocket engine, guided ballistic missile and was also the first man made object to travel into space by way of passing the Karman Line, 62 miles above sea level.

Developed in WW2 the V designation stood for Vengeance Weapon and it was designed

by Wernher von Braun. Von Braun gained his enthusiasm for rockets as a teenager in the 1920s and was further inspired by the development of the Opel-RAK manned rocket cars and rocket

16 | RCM&E

words & photos » Shaun Garrity

The fearsome V2 ballistic missile on its launch pad.

Dan Sharp Collection.

Retro Ramblings | Column

Detailed drawing of the rocket’s internals showing the combustion chamber location. Dan Sharp Collection.

planes. The development program sadly ended because of the Great Depression of 1929 when Fritz von Opel left Germany and emigrated to France, then Switzerland.

This didn’t dampen von Braun’s passion, however, and in early 1930 he attended the University of Berlin where he assisted Herman Oberth in liquid fuelled rocket motor tests. He had gone full circle as it was Oberth’s book ‘The Rocket into Interplanetary Spaces’ that von Braun had bought as a youngster, garnering his initial interest.

Long story short, the Nazi party gained power while von Braun was working on his doctorate and an artillery captain called Dornberger arranged a research grant for von Braun. The initial liquid fuelled rockets he developed were tested at the Kummersdorf test site alongside existing solid fuelled types.

By 1934 he had successfully launched two A series rockets, with one achieving a height of 2.2 miles. Buoyed by this he then wanted to develop much larger gyro guided rockets capable of hauling a 1-ton payload skyward with a 170-mile range. From what I can establish the V2 was developed in 1938 at the Army Research Centre, Peenemunde.

Interestingly, it is alleged that Hitler initially wasn’t very impressed with the V2 and likened it to an artillery shell that merely had more range and significantly more cost. Constructed at the Mittlewerk site by prisoners its main purpose was to be promoted as a Wonder Weapon to help maintain German moral.

Detailed drawings of the V2 were acquired in 1943 by the Austrian resistance, along with locations of the manufacturing sites and these helped the allies formulate a plan to bomb these facilities. Starting in September 1944 more than 3000 were launched by the Wehrmact against allied targets.

After the war, von Braun and another 125 scientists and engineers were sent to Fort Bliss, Texas in the USA under a military operation called Project Paperclip to work on rocket technology for the US Army. In 1960 President Eisenhower moved the group to NASA to develop space travel. Von Braun died in 1977 and during his time in America he also worked with Disney on programs about space travel.

Oh, and first past the line identifying the mystery object was Martin Harris, who emailed me. But thanks to all the others for taking the time.

Another prototype German missile from 1944, the Henschel Hs298 air to air missile, had a design flight range of one mile. Radio controlled using a solid fuelled rocket, it never went into production, with development ending in 1945.

September 2023 | www.modelflying.co.uk

Last month’s mystery item is no longer a mystery.

Estes rocket powered R/C boost glider.

Brilliant fun but a tad expensive to run unless you caught a thermal. This is another model that is back on my ‘I want another one’ list.

ESTES

Anyway, you may be wondering what this V2 ramble has to do with modelling. Well, a few decades ago I bought a rocket boosted R/C canard glider called the Astro Blaster.

Manufactured by Estes, who were well known for their range of free flight model rockets (they were experimenting with a rocket powered boost glider back in 1957), I just had to have one, my inner child having gone into overdrive. I mean, what wasn’t there to like vertical take-off, smoke, flames, speed and no way to shut it off once the burn had started.

On opening the kit I seem to remember being initially disappointed as, like a number of US kits of the time, the foam wing cores were not sheeted and you had to do it yourself.

The die cutting was more die crushed and the balsa selection questionable, but I could have been unlucky. Impatient to get skyward this proved an annoyance, but the kit assembled quickly and my mini tantrum was forgotten.

Finished and pointing almost vertical on the take off ramp, I must admit to being unusually a tad nervous. But to be fair I had never put my expensive (at the time) R/C gear in a winged firework before.

It had an electric fire mechanism with a launch button. Honestly, a real fire button, so after a quick twiddle of the sticks to ensure everything moved as expected we started the countdown. I was expecting ‘10, 9, 8, 7’ etc.

RCM&E | 17

An early Estes advert promoting this branch of the hobby to the masses. (Please don’t try filling in the coupon! – KC)

A full colour advert makes products far more appealing. The Estes range of rockets was huge and you were spoiled for choice.

Model rocketry has been popular for many years.

This Aeromodeller article was from 1963.

but my mate was keen to get it going so he shortened it to ‘10 – fire!’ My first vertical takeoff was an interesting experience and I had to resist the temptation to level her out as the aim was to achieve as much height as possible to get the longest glide. I can’t remember how much airtime I achieved from each launch, and I am sure it was less than my rose-tinted spectacles make me believe, but the expense was worth it for the kudos of being the only rocket man in the club.

Another feature of the Blaster was that you could also easily use a small IC or electric motor as an alternative power source. Additionally, it flew well as a slope soarer, so it was a good all-round model to have in the fleet.

I could fancy another one but no doubt it has become a desirable catch for the dreaded kit collector, destined to be bought at a highly inflated price and stuck in a cupboard, never to see the light of day again. Come on guys, girls, they/them (it’s very confusing and getting increasingly difficult not to offend someone these days), kits were designed to fly, not be hidden away. So please build them or flog them to someone who will stick the small bits of balsa together to make a bigger piece.

If you fly at a noise sensitive site then maybe rocket power could be the answer if you are feeling the need for speed. I mean, who didn’t want to be Dan Dare as a kid?

By 1985 scale rockets had become popular, with competitions for the skilled and dedicated.

18 | RCM&E

There are several books available on the subject.

Bowden’s was first published in 1948.

www.modelflying.co.uk | September 2023

Retro Ramblings | Column

Kwik Fly 3 stripped and ready to re-cover. I managed to retain the original film on the tail and fin.

KWIK FLY 3 - PART 2

As detailed last time, I believed a couple of hours work would sort out my newly acquired flying mouse house. I got that epically wrong.

On close inspection Mickey had nibbled at more bits of the wing than I originally believed and it had been testing out the odd bit of fuselage as well. I managed to save the lower wing covering and the fin and tail, but the rest had to go. A small bonus was the red film came off with ease but the white film delaminated, with the clear plastic coming away from the white coloured adhesive and leaving this well stuck to the balsa. After quite a few hours work I finally managed to remove most of it. Replacing the nibbled wood consumed more hours but finally it was ready to cover. This took a few more hours as it was a multi colour design but eventually I could see the light at the end of the tunnel.

Other problems were sourcing the odd shaped fuel tank, the weird bolt pattern of the motor mount and finding an engine. As luck would have it, I was at a fly in and there were a few bring and buy tables stacked with goodies where I found the exact items I needed. My mate also had a little used Irvine 46 for sale, which was the engine originally fitted by Geoff, so the cowl would be a perfect fit.

The plan was to get it finished so I could fly it in the retro aerobatic slots at the Pontefract

New mounting plates were made for the aileron servos.

I was pleased that I had some red film in stock that almost matched the original to cover them with.

September 2023 | www.modelflying.co.uk

After much hunting around I managed to find an engine mount that matched the firewall bolt holes.

Single Channel & Retro show in July. But there must be a time thief in my house as I’m running out of this valuable commodity at a rate of knots, so time will tell.

LINEAR SERVOS

We received the following email at editorial HQ, and it tied in nicely to a planned item I had for Ramblings and the advertised up and coming servo feature: Having reached the ‘Next Issue’ page of the June issue I am delighted to note that you will be including an article on servo selection and application. Perhaps it’s too late now to raise a question but here’s one that has puzzled me for some time.

My first digital proportional radio (early 1970s), a Skyleader set, was supplied with American EK Logictrol servos. These had twin parallel linear outputs moving in opposite directions which made it easy to connect them via quick links to the control surface pushrods. Being linear one had no worries about the sideways motion of the quick links. Control throw was adjusted at the control horn. I always found these servos to be robust and reliable (in up to 10cc aeroplanes).

Was their demise perhaps due to the conversion of rotary to linear motion (loss of efficiency) and/ or stripping the gear teeth on the linear outputs?

Keith Cherrington

Linear throw servos were once very popular.

The RM Propo book had a wealth of information on linear and rotary servos.

I was always a fan of linear servos, especially for ailerons. It made for a simple, relatively slop free set up, especially when using Bowden cable links directly to the control surfaces. This was obviously back in the day when a servo cost as much as a stately home, so modellers generally used just one centrally placed unit.

Out of the spares box, I pressed some DS821 digitals into service. Not shown is a new ply mounting plate that needed making for the throttle servo, Rx and battery.

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Above: From the top: Bonner (also rebadged

by Skyleader on the 3+1 set), early Gold Kraft, blue German BRUKA reed actuator and a more modern Kraft KPS 11.

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Below: From top left: Orbit PS3, SLM kit built, Orbit PS2, Futaba DigiMax FD11, red HB Precision Micro-Lok, Futaba FD21M, Waltron badged E.K. Logictrol, Skyleader SRC.

Although called linear because of the push pull output they didn’t give a truly linear output to the control surfaces at larger deflections.

The further away from the servo centre the less linear the response exhibited at the control surface due to the arc the control horn goes through; a sort of built in geometrical expo.

Several very early proportional servos were linear, being simply converted from reed actuator mechanics and cases.

I can’t find an absolute answer to Keith’s question re their demise. I would guess they were a little more expensive to manufacture

and the properties of plastics at the time limited how big in terms of output force was achievable, as he suggests. I’m not sure how practical (at model sizes) a leadscrew method of providing a linear output would be for larger servos but I imagine they would be quite weighty when compared to a rotary equivalent.

I don’t think speed would be an issue though as a CNC machine I built several years ago used leadscrews for moving the router head around on the work piece with excellent accuracy.

My favourite linear was the secondgeneration model from Futaba; reliable,

www.modelflying.co.uk | September 2023