i3dm

My Feedback: (51)

If i had a P-20 i'd be out flying it !

BaldEagel

Then I don't understand the information I have been given by two reliable sources that the Pump can not take over 10 volts from the ECU battery? How does 10volts get to the pump to make this information/statement correct?

Mike

i3dm

My Feedback: (51)

Perhaps pump voltage with the (tiny) P-20 pump actually gets to these values while running ? has anyone checked ? ill try to look up ALi's video of the P-20 running to check this..

i3dm

My Feedback: (51)

[youtube]http://www.youtube.com/watch?v=gXkavTVN6YU[/youtube]

Pump voltage maxes out at about 4.7V

mick15

Well there's a surprise. lol.

m

drdoom

My Feedback: (9)

Looks like it is Ready.

Gordon W

If there are 4 wires going to the P-20 pump instead of just two as on my Wren 44's Flightworks pump , then maybe there's some active circuitry within the pump body that maxes out at 10V.

Gordon

Couch Potato

Doesn't the P-20 pump have 2 integral solenoid valves in a block ?

4 wires could be

+ve supply
pump pwm -
kero/gas start solenoid pwm-
run solenoid pwm-

BaldEagel

If you look at the pic on post 1 you will see the valve block by the side of the pump, these plug into the pump for their power and I presume signal, hence the four way plug into the pump you are probably correct on the signal wires for the valves, but the valves are not integral to the pump.

Mike

wojtek

My Feedback: (73)

I know what you mean about boring ! lol I came into the hobby on Jetcat p80 abd p120s ... But some of the most fun i have had with jet engines has been running manual air start on some AMTs i had/have ... Its fun being manually being involved in running up the air, kicking in the gas, backing off the air, lighting the plug, and ramping back up with the air, and being able to have a "feel" for it getting perfect starts [8D] .. then again the thought of lugging around a scuba tank, start valve boxes, etc still made me opt to use my p200 in my latest project over an air start at450 ... fuel and go


~V~

Gordon W

That sounds possible, though I don't understand why the solenoids need pwm - I'd have thought DC on or off would be sufficient, but I've not been around jets long enough to know. If the solenoids do have a common +ve with the pump, one would need to take care not to exceed their voltage limits too - is it likely the solenoids would withstand more than 10V? Just a thought.

Gordon (who always finds his Wren 44s exciting )

BaldEagel

Copy of a post by Dave Wilshire:

Mike

The ECU V10 could run on 3xA123 batteries (ECU accepts up to 14V) but not the P20-pump. This is limited to maximum 10.0V input.

JeyCat recommend to run the P20 only with 2S LiPo!


On upcoming engines using the ECU V10 it will also support 3cell A123 batteries, but for me on small models the weight of A123 makes little point.

(2xA123 cells will not works as they provide too low output voltage, ECU needs 7V at minimum)

Dave

I have had a similar responce from Ali.

Mike

BaldEagel

You guys have put forward some good reasons why the pump will never see the ECU battery voltage, I wonder why two reliable sources have been told not to use three cell A123's and that its the pump that will not take over 10 volts by JetCat? the question has been asked on the JetCat Turbine Clinic thread without any responce so far, It will be interesting to see what transpires.

Mike

Ali

My Feedback: (5)

Hi Mike
The comments that I posted were a direct copy and paste from an email that I received from Roman at Jet Cat. Other than Markus ( Owner and designer) I dont think anyone else at JC has as much knowledge of the turbines as he does.
Regards Al.

Ali

My Feedback: (5)

Hi Mike
The comments that I posted were a direct copy and paste from an email that I received from Roman at Jet Cat. Other than Markus ( Owner and designer) I dont think anyone else at JC has as much knowledge of the turbines as he does.
Regards Al.

BaldEagel

Hi Ali

I just repeated what you had told me and I belived to be correct, others have different opinions, hence this disscusion, it would be nice to get an explanation to satisfy everyone, perhaps we will in the JetCat Turbine Clinic thread.

Mike

Ali

My Feedback: (5)

Hi Mike,
No problem at all . I just wanted to make sure that everyone knew where the information I was providing came from.
Regards Al

Dave Wilshere

Mike

Markus designs the electronics on all JetCat's it was him who had given me the information I posted last week for you. The P-20 pump is magnetic drive...

Dave

AndyAndrews

Lets see the viper Fly!!

bigplumbs

I cant believe it started first time..................... You are using a Futaba

BaldEagel

Yes I know, I just hope the P20 turns out to be as reliable.

Mike

BaldEagel

It seems this was a correct suposition on my part the pump and valves see the maximum voltage of the ECU battery and its the switching on and off from the ECU that controls the speed of the pump and the voltage into it, what is seen on the GSU is the controlled voltage.

The P20 has a requirement for 110cm of fuel line into the turbine from the pump, this is to prevent pulses from the pump reaching the turbine, this is very evident on start up on a Kero burner without the long length of fuel line, but does not seem to inhibit the good starting I have experienced so far, I am running the P20 in a Toki Ducty without a UAT just a pleasted paper clunk filter in the main tank, so far faultless running and so much fun, just grab a fuel bottle and Tx and go fly, no retracts or brakes to pump up, simple winter flying fun.

Mike