Radio control jet international august septemper 2016

THE WORLD’S PREMIER R/C JET MAGAZINE

AUGUST/SEPTEMBER 2016

ON TEST: POWERBOX MERCURY SRS XICOY AIR SEQUENCER

MIKE’S MB-339

A close up look at this outstanding model

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AUG/SEP16 • £5.99

2 MAIN JET EVENT REPORTS: NEW ZEALAND JET SPECTACULAR NYE JETS SPRING MEET

CARF ROOKIE ‘LAST EDITION’ TESTED

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CONVAIR YF2Y-1 SEADART: PART 1

AVIATION DESIGN’S SUPER SCORPION 80 EDF REVIEWED

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CONTENTS AUGUST / SEPTEMBER 2016

Issue 139

EDITOR Tony van Geffen email: tony.vangeffen@traplet.com GROUP EDITOR Kevin Crozier REGULAR CONTRIBUTORS David Gladwin, Colin Straus, Alex Jones, Stuart Hellyer, Ian Titchell Mark Beacham, Dave Wilshere CHAIRMAN Tony Stephenson MANAGING DIRECTOR Tom Stephenson DESIGN AND PRODUCTION MANAGER Nick Powell MAGAZINE DESIGN AND LAYOUT James Scott ADVERTISING SALES Angela Price Tel: 01684 588568 email: advertising@traplet.com MARKETING Ally Alldritt, Abbey Morris, Samantha Minton email: marketing@traplet.com ADVERTISING COPY CONTROL Tel: 01684 588517 email: adcopy@traplet.com PRINTER Warners plc NEWSSTAND DISTRIBUTION Seymour Distribution Ltd. (020 7429 4000) HOBBY TRADE DISTRIBUTION Traplet Publications Limited (01684 588522) US DISTRIBUTION Traplet Distribution USA Ltd., 806 Parkland Ct, Champaign, IL 61821, USA Tel: (001) 217 355 2970 email: info@traplet.com AUSTRALIAN DISTRIBUTION Traplet Publications & Hobbies, P.O. Box 501, Engadine, NSW 2233, Australia.

Tel: (02) 9520 0933 Fax: (02) 9520 0032 email: sales@traplet.com.au SOUTH AFRICAN DISTRIBUTION P.O. Box 1067, Oudtshoorn, 6620, South Africa. Tel/Fax: +27 44 272 5978 email: southafrica@traplet.com PUBLISHED BY Traplet Publications Ltd, Traplet House, Willow End Park, Blackmore Park Road, Welland, Malvern, WR13 6NN, England.

Tel: 01684 588500 Fax: 01684 578558 email: customerservice@traplet.com SUBSCRIPTIONS Ally Alldritt 1 Year subscription prices: UK £35.94 Europe £42.48 W/Wide £45.84 USA & Canada US $78.36 2 Years subscription prices: UK £71.88 Europe £84.96 W/Wide £91.68 USA & Canada US $156.72 BACK ISSUES UK £5.99/US $10.99 Customer Service: 01684 588599 Order Hotline: 01684 588599 Online Ordering: www.trapletshop.com © 2015 Traplet Publications Limited.

All rights reserved.

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SUPER SCORPION 80 EDF

CHECK OUT PAGE 36 FOR OUR LATEST SUBSCRIPTION DEALS ON THE COVER:

This superbly-detailed Airworld Aermacchi MB-339 is owned and flown by Mike Donnelly. We take a close-up look at the creative finish, and performance in the air (TvG photo)

This magazine is sold subject to the following conditions: that it shall not without written consent of the publishers be lent, resold or otherwise disposed of by way of trade in excess of the recommended maximum retail price. All rights strictly reserved. No part of this publication may be reproduced in any way without the prior agreement of the publisher.

All letters must be accompanied by the sender’s full name and address. The publisher cannot accept responsibility for unsolicited correspondence nor some of the opinions expressed. All material and artwork originated by Traplet Publications Ltd., photographs, drawings, plans used in this magazine become the publishers copyright under Copyright law. Some photographs may have been digitally re-mastered.

The Company reserves the right to suspend or refuse any advertisements without giving reasons. Whilst every care is taken to avoid mistakes, Traplet Publications Ltd. cannot be liable in any way for errors or omissions. Nor can the Publisher accept any responsibility for the bona fides of advertisers. © Traplet Publications Limited 2016 ISSN 0968-3291

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Regulars 6 From The Cockpit Editor’s news and views

70 Gas Turbine Performance Comparisons 72 Buying Power

Readers’ free classified advertisements

74 Next Issue

Forthcoming features in the October/November 2016 Issue

Features

POWERBOX MERCURY SRS

58

10 Technically Speaking

In this issue Dave Gladwin takes a look at the PowerBox iGyro 1e plus more new products, tips and topics

16 Convair YF2Y-1 SeaDart: Part 1

In this series Alex Jones takes us through the different project stages of designing and building this amazing model

22 Super Scorpion 80 EDF

This ‘full-house’ 80 mm EDF jet model from Aviation Design for 6S LiPo power is assessed by Colin Straus

30 New Zealand Jet Spectacular

Stuart Hellyer reports from this 10th Annual jet meet

38 CARF Rookie ‘Last Edition’

Ian Titchell describes the assembly and flying of this uncomplicated sports jet

46 Nye Jets: Spring Meet

Mark Beacham reports from the 2nd memorial event at Throckmorton

52 Mike’s MB-339 COVER STORY

NEW ZEALAND JET SPECTACULAR

30

We take a close-up look at the finish and flying of Mike Donnelly’s superb Airworld model

58 PowerBox Mercury SRS

Colin Straus goes in-depth with this latest power management system with optional GPSII from PowerBox

62 Xicoy Air Sequencer

This miniature landing gear and door air sequencer is described

66 Jet Chatter

Dave Wilshere passes on some tips regarding helpful transmitter aids and spotting weary fuel pump and starter motors

NYE JETS: SPRING MEET

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Plus! More features, regular columns, news and reviews from across the complete spectrum of the R/C jet modelling hobby October/November issue will be on sale Thursday 15th September 2016

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AUTHOR & PHOTOGRAPHER: ALEX JONES

Convair YF2Y-1 SeaDart Project

PART 1

A large, twin turbine US NAVY experimental single-seat fighter that has four fifths of the earth’s surface as its runway. Designed by Convair in the 1950s and faithfully reproduced in quarter scale by The Little Jet Company to operate solely from water

SeaDart YF2Y-1, 135764 seen at Wings Of Freedom Aviation Museum, Pensacola, Florida (courtesy WOFAM)

I

n this series we follow the team of modellers building this ground-breaking twin-turbine powered model starting with the research, followed by the model build from start to finish and overcoming technical issues, and concluding with the first flights.

Researching the Type

This project has already taken the team to destinations around the world in the name of research, but after thousands of hours we can finally begin. This is one of three large scratch built composite multi-engined jets we have been commissioned to produce. All are unique but none more than this!

The first task was to research the aircraft extensively. Starting with the obligatory Googling we found plenty of dead ends but it did lead us to San Diego Air & Space Museum that holds the archives for Convair. The curators were beyond helpful and, without their valuable input, this project would be that much harder.

With plenty of original drawings we were certain we could achieve as close to 100% scale fidelity as is possible on an aircraft that had been consigned to history long ago. Along with the drawings we have plenty of historical high-resolution photos from which we can extract scale details.

Our last research trip took us to Orlando to photograph and measure the SeaDart at the ‘Sun ’n Fun’ Museum at Lakeland Airport. This trip was essential as it unlocked some of the issues we had been having when replicating the ski retraction – a geometrical challenge and a huge project in its own right.

Much of the research showed the first SeaDart to be built, being the XF2Y-1. This was the ‘sugar scoop’ aircraft in reference to the shape of the rear end with the

Westinghouse J34 non after burning engines.

We blended the data together to give us all we needed to build SeaDart YF2Y-1.

This was the second SeaDart to be built and went supersonic on 3 August 1954 in a shallow dive from 30000 ft. It was used to develop ski design. Sadly this crashed on 4 November 1954, killing Chuck Richbourg, as he struggled to control a high-speed pilot induced oscillation, which led to the aircraft going beyond its structural design limits.

The first SeaDart XF2Y, 137634

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CONVAIR YF2Y-1 SEADART

This second SeaDart, 135762 is the example to be modelled

The Prototype

The second SeaDart YF2Y-1 is the aircraft we will be modelling and the only one not to survive the programme. This had the twin ski setup like the first and proved very stable on the water and we hope this will translate to our 1:4 scale model.

We made a research trip to Orlando at the Sun ‘n Fun Museum at Lakeland Airport. The Museum curators were helpful and gave us permission to get up close to the SeaDart.

This SeaDart YF2Y-1, 135765 never flew but was finished to the specification developed in SeaDart three.

We spent two days photographing every inch of the aircraft, making templates and taking down measurements to compliment the research already collected from San Diego. This helped our understanding of the ski retraction mechanisms and also proved invaluable for the rivet counter that lurks within all scale modellers... over 100,000 to be applied to our 1:4 scale model.

We were careful to cross-reference this aircraft with our research that showed some differences, mainly due to the passage of time.

With these differences filtered out and our San Diego data merged, we now had enough to make a start designing YF2Y-1, 135762.

We picked the twin hydroski aircraft because it is the most complete flying design that represents the SeaDart 135762, the aircraft that we are modelling, which went supersonic and was the only airframe to do so. The final twin hydroski design on 135762 was essentially the best that the team at Convair could do to reduce the harmonic effect between the fore and main oleo mountings as the ski flexed. The vibration became intolerable in the cockpit on certain even wave patterns, at speeds approaching the 125 knots rotation speed. A choppy larger wave pattern broke up the harmonic.

The single ski design was not able to completely retract because it was made purely to test the effect of the single ski landing and take-off and the effect of wave induced vibration. The test results showed that the single ski, though harder to learn in the same way that a water skier would find mono to two skis, was the way forward. The main oleo struts were parallel and vibration was reduced to tolerable operational levels with the additional help of a variable damping system. Aileron throw was increased and the pilot was able to balance the aircraft and even bank into the turns as a slalom water skier would, dragging the inside wingtip in the water!

As ‘The impossible takes a little longer’ shows, the vibration was not discovered during

On display at Lakeland, Sun ‘n Fun, this SeaDart YF2Y-1, 135765 never flew

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