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Using Xicoy ECU on a Evo Booster 90

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Old 07-17-2018, 02:22 AM
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Jgwright
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Default Using Xicoy ECU on a Evo Booster 90

I have just had success with converting my Evo Booster from the original ECU to the familiar Gaspar Xicoy Fadec. The original ECU would not work and I had acquired the engine with a failed ECU. I thought about replacing the original kero stick which is 12v with the more normal 6V one. Unfortunately the assembly is very difficult to get at as the engine uses sticks at the front like the Jetcat engines. On the Booster 90 this caused problems with combustion. The slots that were needed to accept the needles required small flaps spot welded on the face of the chamber. I did think of using a Wren chamber but in the end decided to leave it alone and use twin voltages.

I also wanted to fit the 2 valves under the cover top make a neat installation. This was achieved by making 2 small glass fibre plates that fitted in place of the old pc board. I soldered the various connections without too much of a problem and secured the Multiplex connectors to the board with acrylic glue. I checked all the connections worked correctly and checked the front intake cover would fit. In the end I replaced the electric motor and bendix with a Ball raced 280bb motor for extra durability. It was a tight fit to get everything plumbed up but it was not impossible.

I then spent a while on the test bench trying to get the engine to start. The Xicoy Ecu was fitted in a plastic box with the appropriate connectors. on the underneath I have the wire connections from the various connectors. I also fitted a relay that closes when it senses voltage on the pins of the Multiplex connector of the Xicoy unit that lead to the kero stick. This then feeds 12 volts from the separate 12v battery to the internal kero stick. The Xicoy unit needs to sense a load on the kero stick line and I got round this by simulating a kero burner using a 25W wire wound resistor. This is the gold part on the outside of the box shown in the photo. It of course does get hot and care is needed not to grab hold of it after a start! The 12v battery can be removed after the start.

Everything was checked and I tried a start, I had problems initially due I think to the long thin copper wire attached to the thermocouple and I hadn’t calibrated the thermocouple properly. This resulted in the engine going straight to switch over and then overheating. After calibrating the thermocouple I solved that problem but I was still faced with a large spike in temperature rise at about 15,000 rpm. Reducing the fuel flow allowed the engine to run past the over temp point, but then it did not have sufficient fuel to reach idle. A lot of head scratching lead me to conclude that the thermocouple outlet on the engine was the problem. It sticks out in the airflow about 3mm between the guide vanes getting overheats very easily, when the engine was clearly not over hot and not glowing red. I tried altering the axial position and this did not cure the problem. I then fitted an external thermocouple to by pass the internal one. I knew that this should work, albeit not look quite as neat as envisaged. After fitting the external one and calibrating it the engine did at least start but clearly needed more fuel during the ramp. Small adjustments have solved the slow start and I now have an engine that starts fine.The original Booster ECU must have had a way of electronically avoiding the flash overheat of the thermocouple. The ECU needed a ring magnet to be fitted into the compressor.

Since making the conversion it has been flown 3 times.There is still life left in old engines!

John



New Xicoy valves on 2 new fibreglass plates


Rather a tight fit to install it!


Multiplex plugs glued in place with acrylic glue


Very neat final installation


ring magnet required for ECU


New 280bb starter motor


Relay that switches the 12v battery on for start


Final installation fitted to the plane
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Old 07-17-2018, 09:29 PM
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Felix Barrao
 
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Great work, John!
Where do you get the 280bb motor from? This sagami motors are great, but impossible to find today.

Regards
Félix
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Old 07-17-2018, 11:31 PM
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Jgwright
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Felix

You are right the best starter motor is not that readily available. I bought 6 when I last saw them advertised. I still have one left but it is not for sale!

There are 370 6v high speed electric motors on Ebay but I haven't tried them. Superficially they look much the same spec as the old Speed 300. As you know JetCat used to fit a ball to the shaft to take the end load. Having said that they are nowhere near as good as a ball raced motor. The best motors now available are brushless, but none make a plug in 0-7.2v analogue to brushless converter complete with ESC.

John
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Old 07-18-2018, 04:25 AM
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Felix Barrao
 
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Yes, I have tried the " chinesse" 370 6V and works the same way that the speed 300. The splined shaft is the same also. With the " ball " trick ( also used in the old Jet central) works fine, but doesn´t last forever like the 280BB.
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Old 07-18-2018, 06:48 PM
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Johnny Isaiah Woods
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Hello John,
Did you place the magnet in the spinner nut? or in the compressor wheel. Also, did you replace the bearings? I plan to do the same to my 160. Thanks for giving such a great tutorial.

Johnny
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Old 07-19-2018, 12:09 AM
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Johnny

Thanks for the kind comments, I machined a groove in the top of the compressor and fitted it in the groove. The compressor nut does have enough 'meat' in it to machine in the same way. The ring magnet was bought from Gaspar. Yes I replaced the bearings and I balanced with my commercial balancer. I have since doing this conversion converted a Jetcat 120 to the Xicoy ECU and that too starts fine. I will post a separate thread in case it is of interest.

John
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Old 07-19-2018, 09:12 AM
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Felix Barrao
 
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I did xicoy fadec conversions to P20, P60, P70, P80, P120 and P160.
Some conversions with the magnet ring into the nut, but it´s difficult to center in the lathe, and not too much room to fit the magnet, You loss some thread to. It´s better way as John says to insert the ring in the compressor wheel.
P20 and P60 has magnetic sensor, so, not needed to add the magnet for the conversion.
Start of the P160 Kerostart with xicoy fadec.

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