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-   -   Jetcat P120 thrust level help needed (https://www.rcuniverse.com/forum/rc-jets-120/11636227-jetcat-p120-thrust-level-help-needed.html)

ajp 02-02-2017 02:49 PM

Jetcat P120 thrust level help needed
 
I am getting a older model ready to fly again. It has a 14 year old Jetcat P120 in it. I have the rpm set to 115000, and cannot find the graph that compares thrust levels to rpm. Does anybody know what thrust level I am getting at 115000?

Thanks
Paul Appelbaum

Vincent 02-02-2017 03:08 PM

1 Attachment(s)
Here is what I found on an old rcu thread.

rhklenke 02-02-2017 03:32 PM


Originally Posted by Vincent (Post 12302267)
Here is what I found on an old rcu thread.

Good find! I always thought it was interesting how the majority of the thrust is at the top-end. A 6.5% reduction in RPM reduces thrust by over 20%...

Bob

ajp 02-02-2017 03:51 PM

Thanks, that is exactly what I was looking for

Paul

Vincent 02-02-2017 03:52 PM


Originally Posted by rhklenke (Post 12302275)
Good find! I always thought it was interesting how the majority of the thrust is at the top-end. A 6.5% reduction in RPM reduces thrust by over 20%...

Bob

After taking a quick glance at it I was surprised too.
Vin...

Zeeb 02-02-2017 04:30 PM

Typical of turbine engines. They say with full scale that 50% of the thrust is created in the last 10% of RPM. I don't imagine their tiny counterparts would be much different.

John Redman 02-03-2017 10:44 AM

Paul,

The thrust figures listed by Vinny are for the latest versions of the P120's, mainly the SX version. If your engine is indeed 14 years old and has a serial number of under 1400 I would guess it will push around 24 - 25 pounds at full tilt unless it has been fully upgraded with the new style compressor, EGV, Diffuser, Chamber. The P120's from the serial number I listed above and older were around 24 - 25 pounds of blow. At 115,000 I would guess it is pushing closer to 16 pounds.

Just what I recall from running thousands of these engines over the years on test stands, etc.

Vincent 02-03-2017 03:16 PM

[QUOTE=John Redman;12302529]Paul,

<<<<The thrust figures listed by Vinny are for the latest versions of the P120's, mainly the SX version. If your engine is indeed 14 years old and has a serial number of under 1400 I would guess it will push around 24 - 25 pounds at full tilt unless it has been fully upgraded with the new style compressor, EGV, Diffuser, Chamber. The P120's from the serial number I listed above and older were around 24 - 25 pounds of blow. At 115,000 I would guess it is pushing closer to 16 pounds.

Just what I recall from running thousands of these engines over the years on test stands, etc.>>>>

Hi John...are you sure about that the thread I got that info from is from 2006 and the P120sx had a max rpm of 125k and 30-31lbs thrust??
Vin...

John Redman 02-07-2017 01:20 PM

Yes Vin, at 125K the P120-SX would hit 30 - 31 pounds. I am sorry, I was thinking the traditional 123K.

mblue77 07-14-2018 06:28 PM

I have a P120sx, serial no. 3476. I noticed that the ecu is set
at 123K max rpm. Can this turbine be run safely at 125K, and if so
can that be programed through the GSU?

ledd4u 07-15-2018 03:50 AM


Originally Posted by John Redman (Post 12302529)
Paul,

The thrust figures listed by Vinny are for the latest versions of the P120's, mainly the SX version. If your engine is indeed 14 years old and has a serial number of under 1400 I would guess it will push around 24 - 25 pounds at full tilt unless it has been fully upgraded with the new style compressor, EGV, Diffuser, Chamber. The P120's from the serial number I listed above and older were around 24 - 25 pounds of blow. At 115,000 I would guess it is pushing closer to 16 pounds.

Just what I recall from running thousands of these engines over the years on test stands, etc.

Your statement is neutral in context. Before 1400 24-25lbs. Above 1400 25-25lbs. Sounds like tax brakes. Just a little confused about the statement. I own a serial number 2455 and it’s definitely more than 25lbs. Non SX, those are simply a POS from what I read.


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