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Thread: Test LB


  1. #1

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    Test LB

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  2. #2

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    RE: Test LB

    Heading: AAmotive prototype work for a really new 2.5 cc Taipan

    Background

    Those who have been interested in model engines for a long time will know what a "'Taipan" is. These engines are named after a particularly aggressive - not to mention lethally venomous - snake found only in Australia. Taipan was once a popular brand known to aeromodellers the world over. Developed by active aeromodellers for use by aeromodellers, the manufacturer of Taipan, Gordon Burford & Co Pty Ltd., was always approachable and willing to listen to and accept feedback from users.

    Adelaide Aeromotive ('AAmotive') have been quietly working on a range of new glow and diesel engines largely based on the original designs. Many are nearing production status, which is good news for those who appreciate these home-grown Australian products. The new designs, while incorporating many refinements, are faithful to Taipan's heritage, and particularly their reputation for toughness and relability. The tradition of support continues, as in addition, a repair and upgrade facility has been established by AAmotive for owners wishing to restore worn out or damaged engines from the Burford stable. Parts and service for Taipan and Glo-Chief engines is a firm committment from AAmotive, with a focus on quality control which is increasingly rare in these days of "commoditised" aeromodelling.

    The Mark 3 2.5 cc Taipan Glow. A humble engine ... or was it?

    In the late 1960's Gordon Burford released his Mk 3 2.5 cc glow engine. It became his biggest seller in terms of volume, perhaps due to it's being the right product at the right time. A simple, iron and steel plain bearing crossflow scavenged design, it nonetheless performed well by the standards of the day. Reports by independent testers including Peter Chinn were encouraging. With it's blast finished one piece crankcase, black cooling fins and natty "lightning bolt" motif on the intake port side, it was not only reasonably priced, but also well made. As icing on the cake it looked attractive and modern by the standards of the time.

    To round out it's appeal options were available including an effective bolt on muffler, and R/C throttle with true twin needle fuel metering. Amazing foresight for an engine released in the 60's, when you think about it.

    It received a number of upgrades throughout its production, including minor external and internal modifications. However no real change was made to internal design to increase power. Final examples wore black cylinders and heads, and bore a '2.5' crankcase insignia rather than the earlier '15'.

    Despite it's sales success, the engine was not quite what it was originally intended to be. As conceived it was to have twin ball races and Garafoli inspired "vortex porting". However, this did not eventuate, perhaps due to legal concerns surrounding rather dubious patents held for vortex porting at the time.

    So the engine, while perfectly tractable, reliable, and very well suited to its role of sport and beginners duties; was not the truly potent performer it could have been.

    A short walk down memory lane ...

    In 1974 your contributor acquired a late production Mk 3 Taipan glow 2.5 cc (commonly known as a 'lightning bolt', which for ease of reference I shall shorten to 'LB'). Pride of ownership for a twelve year old was immense. After powering his Aeroflyte C/L trainer, however, it was replaced by an OS 15, which had an edge on power. Until late 2011 it sat unwanted in it's box.

    How many of us have engines like that?

    Worn out LB's receive a makeover - and the old Taipan design grows some fangs!

    In 2011 I acquired two further very battered early run LB's from an estate. Each was in considerable disrepair with various parts broken or missing. I wondered what to do with them. Sell? no, I could not do it, and who would want them? Bin them? in all conscience I could not do that either.

    So, late in 2011 I sent them to AAmotive as a gift, with another more collectable Taipan for renovation, thinking perhaps they could be used for parts as donor engines. My belief was they were beyond repair. How wrong I was.

    David Burke, CEO of AAmotive said he wanted to put the good bits from the two old engines together for use in an experiment. He required data to validate a proposed revisiting of the style of porting originally anticipated for the engine for it's proposed rebirth as conceived. Would I agree? And if so, could I do some testing for him? Umm ... does a bear ... in the woods? Delighted to help, and excited at the prospect of this long dead model being re-born, there could only be one answer.

    Shortly thereafter a parcel containing an engine made up from the old LB's arrived on my doorstep. "It's a Taipan Jim; but not as we know it" my mind whispered when I looked through the exhaust port. It had a new piston and cylinder ... and I mean new, as in a new cylinder with obviously modified porting! Compression felt very strong. I was directed to do some back-to-back testing on a range of props with my original LB as a "control".

    Could this "bitzer" hybrid with it's new piston and modified cylinder outperform my never dissassembled example?

    Testing, testing and more testing ... with the result being vindication of concept

    Using the manufacturer's specified fuel containing 25% castor oil and 5% nitro methane, balance methanol, careful running in of the engine was carried out. Testing then proceeded in earnest. Results exceeded my expectations. Some data:


    Fuel: Composition as above

    Plug: Fireball Yellow (medium heat range as factory supplied with the LB engine)

    Temperature: 26 degrees C.

    Humidity: High (barometric not taken however)

    Elevation: 120 meters AMSL

    All tests were undertaken twice to verify integrity of data.

    LB standard

    Prop Max RPM (Muffler) / Max RPM (Open)


    APC


    7x3 14,300 / 14,400

    7x4 13,200 / 13,300

    7x6 12,000 / 12,100

    8x4 11,200 / 11,400

    9x4 9,900 / 9,900


    Kavan Nylon


    8x4 11,700 / 11,800


    Taipan (black gf reinforced)


    8x4 11,500 / 11,700


    LB Hybrid


    Prop Max RPM (Muffler) / Max RPM (Open)


    APC


    7x3 16,500 / 17,800

    7x4 15,800 / 16,800

    7x6 13,700 / 14,000

    8x4 12,500 / 12,800

    9x4 10,600 / 10,400


    Kavan Nylon


    8x4 13,100 / 13,300

    Taipan (black gf reinforced)


    8x4 12,800 / 12,800


    The converted engine displayed no bad habits. It started readily by hand despite being tight, and was always smooth and well behaved. It was if anything even easier to hand start than my original spec LB.

    Hybrid Testing Endnote

    Subsequent tests on the "hybrid" modified LB revealed further performance gains on same fuel, up to 18,900 rpm steady on the APC 7x3 with open exhaust. Favourable atmospheric conditions may account for some of the improvement, but to my mind it is likely the engine with it's new P&L set was still "freeing up".

    So, where to from here?

    After seeing the hybrid LB perform (perhaps as the LB always should have!) you can imagine the grin on my face when David offered to convert my old LB to the new porting as reward for carrying out the tests. It took me about 2 milliseconds to accept. It may also be converted to diesel, but that is another story. I am informed it will be the sole AAmotive modified plain bearing LB with vortex porting. However, is all this experimenting leading to a dead end? Definitely not!

    While AAmotive will not produce another plain bearing LB, they have the original Taipan tooling for the twin ball race ('LB TBR 15') version of the engine incorporating vortex porting. The mission is to volume produce it for sale. It will suit a number of specialised competition classes in F/F and C/L. Development is well under way. All being well the re-born ball raced LB engine will see the light of day, as originally conceived. Mufflers and an R/C throttle will also be offered to maximise its appeal.

    Is it intended to compete with the latest chinese ABN/C schnuerle ported 15 size engines? No. It is designed to be a good, powerful sports engine of conventional lay out which will use best quality materials. Offering pride of ownership and lasting ruggedness, there will be full spares and factory servicing back up at fair prices. In other words, it is to embody all of the qualities of the 'Taipan' marque. An engine with heritage offering lasting value.

    I am looking forward to getting my hands on one for pre-production testing. More to follow towards the end of this year.

    For Further Information

    For those who wish to know more about Gordon Burford's engines, I unreservedly recommend Maris Dislers book titled "Gordon Burford's Model Engines". The history of the LB and it's performance figures as recorded by Mr Dislers appear in pages 95 to 97 of the book. Some photographs from these pages will be reproduced below.This book is well written and beautifully illustrated. Meticulously researched, with contributions from other notables, it contains a wealth of information and hard data on the Burford designed engines.

    Peter Burford, son of Gordon Burford and a highly regarded model engine designer in his own right has in an historical context provided critical technical support. He continues the Burford family's tradition of fine craftsmanship at:

    www[dot]peterburford[dot]com[dot]au

    For more inforamtion on Adelaide Aeromotive please refer to their website:

    aamotive[dot]com[dot]au

    [dots omitted to prevent spybot activity].

    DISCLAIMER

    If you have read this far, thanks!

    So who am I? Just an enthusiastic amateur aeromodeller with no skills that set me apart from anyone. I have no business interest in AAmotive. I have never personally met David Burke or anyone else at AAmotive, and I am not remunerated for my involvement.

    I paid retail price for my two examples of the current AAmotive offerings. Why? I just like model engines, and I am a life long Taipan appreciator (as you may have gueessed). It has been a pleasure dealing with an ethical Australian manufacturing business. To be included in development test programme of the new AAmotive range is exciting, and for my part, an honour.

    [b]Photographs[b]:

    Images 1 & 2 - original LB (black head) with hybrid LB (natural head) prior to testing

    Image 3 - hybrid LB spinning a test APC prop during running in

    Image 4 - original cylinder from donor engine (all black) and hybrid cylinder (with natural aluminium insert). Crankcase in background is for a different (larger) AAmotive prototype engine.

    Image 5 - "raw" crankcase casting of proposed new LB (as per original conception with provision for front ball race) and an original silencer with some minor damage.





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  3. #3

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    RE: Test LB

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