Springbok Flyer

Hi guys,

I am about to install a Xicoy telemetry unit with my KingTech 180 and KingTech 210 enigines, using an 18MZ. The default pump factor for the unit is 400, but I am sure by now there must be many pilots out there who have already tested these two engines and found the sweetspot. What have you found the pump factor to be on these two engines - it will be nice to have a tried and tested pump factor for my first flight, rather than just using the Xicoy default of 400 and then having to recalabrating.

Thanks for your help.

Jan

George

My Feedback: (57)

Sorry Jan,

I thought you were taking about the pump limit. Mick's reply clarified it.

mick15

The easy way I found was to set it to 300 then adjust the fuel tank size from there. 3l gave me a good alarm point.

m

Springbok Flyer

Hi guys,

Surely, every engine will have it's own pump factor and will only need finetuning based on our individual throttle usage. Anyone have a pump factor that is working with either of these engines (without fudging the tank capacity)?

Jan

Springbok Flyer

Hi George,

The manual calls it the 'Pump factor'.

Jan

mick15

You asked if anyone had a pump factor for the 210, I answered your question, you didn't mention tank capacity. The two parameters are interdependent for an alarm situation, there is no fudge as you suggest.

m

Springbok Flyer

Mick,

The pump factor as explained in the manual is not dependent on the tank size. The tank size is only a figure (stated correctly) that will enable the pump factor to determine the fuel remaining in the tank

From your answer I understood that you chose 300 and then found that a 3 liter tank size will give you the correct fuel remaining in your model. If indeed your model has a 3 liter tank, then I humbly apologise - if not, then it is a fudge to get the remaining fuel to tally.

Thanks anyway for your answer. Now at least I also know that you were referring to a 210 and not the 180.

Jan

number27

K170G tank size 4.8 litres pump factor 340
k210G tank size 4.8 litres pump factor 350
Jet Munts 140 XBL tank size 4 litres pmp factor 330
trail and error
set tank size, set pump factor, fly, land, empty tanks, adjust
no simple way

ticketec

My Feedback: (2)

Thanks Steve,

ive been looking for a starting pump factor for the M140XBL myself!!

dave

Springbok Flyer

Hi Steve,

Yes, you right. That is exactly why I asked the question, because someone (like you) will have done it already. So like Dave, I can enjoy the benefit of your trial and error.

Maybe we should start a post and report all the pump factors for engines using the Xicoy telemetry - it will be very helpful to all pilots setting up with thise engines.

So as a guess I think the K180 will be around the 340 mark then.

Cheers,

Jan

Len

My Feedback: (3)

My Merlin 100XBL likes 260 as its pump factor.

Springbok Flyer

Hi Len and Steve,

I detect a pattern developing here which might suggest some very simple starting pionts with various size engines. So far we have:

TURBINE SIZE/PUMP FACTOR
210/350
180/342
170/340
140/330
100/260

I will update this post as we get more guys telling us their findings.

Thank you for your input.

Jan

luge_racer

Hmmm... so it seems like for my K120, 300 should be a good starting point.

Springbok Flyer

Yes, 300 sounds like a good point to start on a 120. Let us know what your final pump factor turn out to be and I will add it to the list above. Once I hsve settled my 180 I will post that pump factor too.

Cheers,

Jan

Springbok Flyer

Hi guys,

I have now flown and fine tuned for the 180, a pump factor of 342 worked almost 100%. In fact it is quite amazing. My Viper has 4550ml of tank capacity; after landing with 27% fuel remaining (1228ml), I drained the fuel and actually had 1265ml left. Definately good enough for me...LOL.

Cheers,

Jan

luge_racer

Update on the K120G. After a few flights I have my pump factor set at 200, with 3.4 liters of fuel (sky master f-15). Last landing was with 17% on the telemetry and about 19% actual fuel load. So, close enough for me. I might fine tune it later. I'm a little concerned that the number is so low comparatively.

Springbok Flyer

Yes 200 sound very low on a K120, as Len above is using 260 on his 100.......

Jan

LA jetguy

I'm using 75 for a K45... Fairly accurate

Springbok Flyer

Hi guys,

I have had 5 flights with a K210 in my Ultra Lightning, tank size 5800ml. Started with the 350 tank factor as suggested by Steve, but the telemetry thought I had 48% left instead of the 58% I actually had. After playing a bit on subsequent flights with the pump factor, I am now on 310 which on my last flight suggested I had 39% (2262ml) left. I actually had 2310ml (40%) left - so close enough for me.

This little experience bears out exactly what Steve suggested - trial and error, nothing simple. It also seem that there is a lot more at play here as the pump factor is obviously not based only on the engine and or tank capacity, but also the pump and the general installation.

My suggestion to anyone trying to set up the correct pump factor is to go about it as follows:

- Input your exact tank capacity.
- Start with a pump factor from the suggested ones in this thread.
- After the first flight, check the telemetry against the actual fuel left.
- If the telemetry is lower than the actual, then reduce the pump factor by 20 to 30 for every 10% of difference. Visa versa if it was the other way around.
- After the next flight check again and adjust from there.

Do not change the tank capacity to get the correct result - you will only fool yourself and the rest of us too.

Good luck and let us know what you ended up with. Please also tell us what model it was.

Cheers,

Jan

Gaspar

The fuel used on ecus using brushed pumps is measured indirectly by measuring the electrical power consumed by the pump, sothe different pumps and fuel installations and fuel type make differences between one engine and another of same model. Also changes in fuel installation and pump wear will ask for recalibration over time, although a sudden difference from measured and real usually points to clogged filters. On brushless pump ecus the fuel is measured by effectively counting the revolutions of the pump, so the precision and stability is much much better.

For calibration, I would suggest the method in the instructions, calibration in one flight. if using a factor of 350 you had a 48% displayed but 58% real, then just do the math:

350 x (100-58) / (100-48) = 282

No need of trial and error in several flights… Of course the precision of the calculated number always depend of the initial measures.

Gaspar

JSF-TC

My Feedback: (2)

Gaspar,


After chasing the correct pump factor on my Merlin 140 XBL installation over a few flights with major swings in the updated pump factor, I believe that I found an error in your described calculation of the new pump factor value.


Example;

Tank size = 2000ml
Initial Pump Factor = 350
Landing Fuel Remaining - displayed (FD) = 10%
Landing Fuel Remaining - measured (FM) = 20%

Based upon your quoted calculation, PF(new) = PF(old) x (FD/FM), that would give a new Pump Factor of

350 x (10/20) = 175

which is a drastic change for what is only a 10% (200ml) of fuel error.


I believe that the correct calculation should be based upon fuel quantity USED, not remaining.


Keeping in the displayed percentage fuel format, that would give;

PF(new) = PF(old) x ((100-FM)/(100-FD))

Which =gives 350 x (100-20)/(100-10) = 350x(80/90) = 311


Dropping the Pump Factor from 350 to 311 to correct the above example seems a much more intuitive change to correct the 200ml fuel error than halving the original value.

Using the above revised formula, I zeroed in on a corrected pump factor with my Merlin 140 after only one flight.

Please advise if you agree with my new formula.

Regards,

Paul

Gaspar

Hi Paul,

Oppss yes, the correction should be calculated using the fuel used, not the fuel remaining. Thanks for spotting the error, i have corrected my post and the docs.

Thanks again,

Gaspar

Springbok Flyer

Paul and Caspar,

Neither of your methods are working for me. If you look at my example above you will see what I mean. Only by trial and error could I get it right on my K210.

Cheers,

Jan

wfield0455

My Feedback: (7)

Gaspar,

I have 2 Kingtech K140Gs. One is using the FC1 and the pump facter shown in this thread works quite well. The other uses the first generation Xicoy Jeti telemetry interface and if I use the same pump factor as for the FC1 when I land I still have 50% fuel remaining but the telemetry adapter indicates 0% fuel.I have carefully measured the fuel capacity of both models and it is set correctly in the interface. Does such a large difference in pump factors for 2 similar turbines sound possible ? Also, the Jeti telemetry adapter is the first generation version. Has there been any changes in the software that could explain this ?

Thanks for any information.

Springbok Flyer

Paul and Caspar,

I think the formula should be:

FD-FM = 10%, then PF (new) = PF (old) × 0.9. If the FD is more than the FM, then the 0.9 becomes 1.1 instead. So basically using the difference between FD and FM to adjust the PF.

This way in both my and Paul's experience where the FD was 10% less than the FM, the new PF will be 315. Which again is very close to my actual 310 and Paul's 311.

Regards,

Jan