AMT Olympus HP涡喷发动机评测

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作者：COLIN STRAUS
图片：COLIN STRAUS
原载《Radio Control Jet International》杂志2014年04-05月刊

The Olympus HP comes with a very full complement of ancillary and support parts, this even including charge leads for the ECU battery and EDT

    AMT Turbines from Holland are to my knowledge the second company in the world that produced commercial model sized turbines, starting with the very successful Pegasus,which was first available back in 1994. They are now the longest surviving company still manufacturing turbines for model use,although more recently the company has been focusing more on the lucrative UAV and drone markets, developing larger and more powerful turbines.
    Given this long and very successful history it is surprising that until now no AMT engine has been fully-tested for RCJI, however thanks to David Gladwin, who has kindly loaned his new Olympus HP for this issue’s test, we can finally add AMT to the many brands of turbines that have now been evaluated.
    AMT produce three turbines for general model usage, these ranging from the Mercury HP of 88 Newton thrust, through the latest version of the Pegasus mentioned earlier, this latest Pegasus HP providing 167 Newtons of thrust, and on to the largest model sized turbine, this being the aforementioned Olympus HP under test, which is listed as having 230 Newtons of thrust. AMT also offer two larger turbines, which are aimed at the
drone and UAV markets, these being the Titan with 392 Newtons thrust and the even more powerful Nike with no less than 784 Newtons,whilst a third and larger still engine named Lynx with a huge 1569 Newtons of thrust is due out soon!

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The engine is superbly produced and finished, note the one-piece main case and exhaust cone, the external igniter and the protective covers for intake and exhaust

In the Box

    Supplied in a heavy-duty cardboard box, and with extensive foam packaging, the engine itself was the first item removed for inspection, and the immediate impression was of the superb quality and finish of the exterior of the turbine. The main body of the turbine, including the exhaust cone, is produced in one piece, with an attractive brushed finish, whilst the front cover is a flawless purple anodised unit.
     The compressor is very neatly produced, as is the turbine wheel and the internal cone inside the exhaust, and the large electric starter bullet is machined from alloy, as are its supports. Externally there are three Festo connectors fitted through the front cover, one for the fuel input, the second for the kerostart supply whilst the third is left plugged, although it is available for air input for starting should this be required.
     The kerostart igniter is fitted externally, and has the input for the starting fuel supply tube,which runs from within the front cover, whilst the thermocouple is installed through the two mounting straps and into the exhaust cone. Notable of the thought that has gone into the engine are the moulded covers for both intake and exhaust, these ensuring that nothing can get inside the engine until they are removed before running the engine – should the engine be accessible once installed in a model these covers could be fitted between flying sessions for additional protection.
     There are a number of ancillary items supplied along with the turbine, the fuel pump is another superbly produced item, having a machined aluminium finish, whilst the ECU is somewhat unusual these days in that it is relatively large, and has no less than 12 individual cables fitted, all of these apart from the Telemetry lead having to be connected to various other components before the engine can be run.
     A pair of very neat but rather large solenoid valves are supplied, a standard unit for the Kerostart system, and a high flow version for the main fuel supply, and the large EDT (Engine Data Unit) is again unusual, as it includes a battery that must be charged, and it does not have the ability to program the ECU,this job being done using the CTF (Combined Throttle Function) switch, either independently or in conjunction with the data being shown on the EDT.
     Also supplied is a 4-cell, 2500 mAh LiPo ECU battery, as well as a matching charge lead, as well as a charge lead for the EDT, computer interface lead, fuel tubing and filter and CD containing the full manual, which is an extremely detailed and well written English language publication of over 60 pages, and which covers every aspect of safely operating the engine.

A close-up of the intake area showing the quality of finish of the front cover and the compressor itself

A view down the exhaust cone showing the inner cone and the turbine wheel

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Like every other part of the Olympus, the fuel pump is beautifully produced, however it is both larger and heavier than pumps supplied with competitors’ engines

On Test

     It did not take long to install the Olympus and its ancillary components onto the test rig and carry out the programming to the radio being used. The first starting attempt did result in a failed start, and it took a couple more tries before the engine started and ran up to idle and control was passed to the transmitter. I suspect that the problem was due to some air bubbles remaining in the fuel and kerostart lines after the priming procedure had been carried out, and the quite rapid start regime of the engine resulted in this air being ingested and causing a flameout.
     Once this slight hiccup had been overcome starting proved to be quite straightforward and took less than 50 seconds before control was passed to the transmitter. Once the engine had stabilised at idle the throttle was opened to full and the engine accelerated to full power very rapidly, settling quickly and precisely to the 108,500 rpm specified, although it was noted that the idle rpm was slightly above the 36,000 detailed in the manual at 36,500 rpm.
     With the engine running smoothly the test programme was started, with data being taken at idle and then at four further points up the rpm scale, it being noted throughout this that the engine ran exceptionally smoothly. The maximum thrust was measured at a corrected figure of 226.5 Newtons, which is just slightly below the 230 Newtons claimed, whilst the fuel consumption was found to be slightly above the claimed 640 gr/min (800 cc) at 675 gr/min (845 cc).
     Acceleration of the Olympus HP was very fast at just over 3 seconds from idle to full power, with the response once over around 1/4 throttle being almost instantaneous. It was however evident that some adjustments might be required before the engine was installed in an airframe as the engine suffered from a transient period of what might best be described as a booming resonance at between 2/3rd and 3/4 throttle whilst accelerating,unless the throttle stick was moved slowly.
     This noise only occurred for just under a second, but was rather loud while it lasted. I suspect that the problem may be that the very fast acceleration of the engine is on the very edge of inducing compressor stall, particularly as the engine is being operated statically, so is experiencing much lower intake air pressure than it would when in flight.
     Speaking to David after the testing, he mentioned that his AMT Pegasus also has this characteristic when running on the ground,but that once the model is airborne it disappears completely, so it is quite likely that flight testing will prove that the Olympus HP behaves in a similar manner, however if it does occur in flight it is likely that reducing the fuel flow during this stage of the acceleration will effect a complete cure.
     Apart from this relatively minor issue the Olympus behaved impeccably, with very smooth running characteristics, a complete absence of vibration, and absolute stability at all of the rpm points selected during the test running. The deceleration time was measured at between 3.5 and 4 seconds, which is also an excellent performance. No other problems were encountered during the testing programme, and in fact the engine proved to be very simple to operate.

The ECU is again a sizeable unit, and although not particularly heavy, the weight of the myriad of cables does add to the total

Two of these neat solenoid valves are supplied, a standard one for the kerostart and a high flow version for the main fuel supply

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Conclusion

    In conclusion, the AMT Olympus HP is a superbly engineered, very high quality engine with equally high quality ancillary components,however perhaps partly due to this it is significantly heavier than other engines with the same performance. It is now also showing its age in terms of the size of the ECU and the quantity of cables required between it and the various other system components, as well as the size and weight of the fuel pump and solenoid valves.
     The running characteristics of the engine are very good indeed, it runs particularly smoothly, and due to its superb build standard it gives every indication of being a very long lasting and reliable turbine power source.

AMT Olympus HP涡喷发动机评测

AMT Olympus HP涡喷发动机评测

AMT Olympus HP涡喷发动机评测

AMT Olympus HP涡喷发动机评测

AMT Olympus HP涡喷发动机评测

The Engine Data Terminal is used purely to display information; it is not used for programming or setting up the turbine

AMT Olympus HP涡喷发动机评测

The Olympus on the test stand – ready for its first run

Contacts：
www.amtjets.com

AMT Response
     Since the test on the Olympus HP has been completed AMT have advised that from the middle of 2013 the Olympus HP has been supplied with a redesigned diffuser stage which eliminates the compressor stall issues found with the test engine and which also gives 5 to 6 Newtons more thrust at the same maximum rpm.
     Further to this AMT have also advised that the standard maximum rpm of 108,500 can be raised if required to 110,000 to give an additional 10 Newtons thrust, without adversely affecting engine wear or the warranty.