Malcolm H

Hi Ed,

It would be very useful to us Jeti users if you could expand a bit more on why the Jeti needs more compensation? Hopefully when it is set to "linear" it should produce a linear receiver pulse output to motor rpm response (or at least approximately so), so it's kinda disconcerting to hear that it needs more help than other controllers.

Thanks,
Malcolm

NJRCFLYER2

My Feedback: (42)

Malcolm, the Jeti response is not linear. You don't really get a true linear response from any ESC that I've tested, but the Jeti needs more than twice as much compensation as a Castle, YGE or OS for example. I don't think that should be taken as a negative, it's just a difference that needs to be accounted for when configuring the system. Jeti's have been used successfully around the world for a good while now, and pilots have typically adjusted their throttle curves at the transmitter to get the response they want. None of that changes with the Throttle-Tech, i.e. you will most likely end up making some kind of adjustment to the throttle curve at the transmitter, but you start out with linear. The Throttle-Tech compensation factor should be adjusted first, to get it to where the start and end of the flight (and all the way through the flight) have the same, or very similar response. Then you adjust the transmitter throttle curve, and you're good to go.

I will post some data later this week or over the weekend to better illustrate how it all works, Tax prep ate my lunch this past weekend and I'm catching up on things for the next few days.

Bottom line though, use a Jeti if you like them, or a Castle, OS, Futaba, or YGE. We'll be testing other ESC's as well. The Throttle-Tech compensation factor was designed to be configurable because not all ESC's behave the same. All that is really changing is the FlexLink configuration software that runs on a PC will now allow a wider range of compensation to be set. The Throttle-Tech firmware that runs in the controller board is unchanged. I expect to release a FlexLink update within a week from now.

Malcolm H

Hi Ed,

Thanks for that.

Please see PM.

Malcolm

NJRCFLYER2

My Feedback: (42)

Malcolm, did you get my PM reply? I've had some problems on occasion with PMs getting through.

Malcolm H

Yes got it Ed thanks and I replied.

Malcolm

NJRCFLYER2

My Feedback: (42)

FlexLink release V2.2.0.0 has been posted to the Tech-Aero website downloads page. Changes to the FlexLink configuration software now allow a widened range of configuration parameters to be applied to optimize use of the Throttle-Tech system with Jeti Spin and Mezon speed controllers.

NJRCFLYER2

My Feedback: (42)

In advance of publishing a Tech-Tip that gets into more detail, just a quick note about how to configure Throttle-Tech to optimize its use with Jeti Spin and Jeti Mezon controllers. A good starting point is to set the compensation factor to 70. You may find that it needs to be set somewhat higher, depending on your particular combination of controller and motor. Once you have determined the compensation factor setting that suits you best, you may want to adjust the throttle curve in your transmitter for midrange response feel. The ESC throttle curve should always be set to linear.

Anthony-RCU

My Feedback: (2)

Hi Ed, thanks for the help with my setup with my set up the new software is much easier.

NJRCFLYER2

My Feedback: (42)

You're welcome Anthony. Just curious, did setting the compensation value to 25 for the Castle get things evened out to where you want them to be? I'm assuming you were at the default of 20 to begin with.

vbortone

My Feedback: (2)

Hi Ed,

For contra using Jetti, What is the experience? I just set it up to 70 and I will check. Before, It was on 20 so it will be interesting to see the different. I really haven't have chance to flight much so it will be difficult for me to report results. Any feedback on contra with Jetti is welcome.

Thanks,

NJRCFLYER2

My Feedback: (42)

Vince, I don't have experience with the Contra and Jeti combined. Dave Lockhart flies Castle with the Contra and I believe dials the compensation factor back just a little as compared to a conventional 2 blade. 70 is probably a good starting point with the Jeti. You could also just see what the static RPM or watts expended are with a full power run-up at the end of a flight that has Throttle-Tech disabled, and then adjust the compensation factor to get you right around the point with a fully charged battery. After that, just take some readings at the start and end of flights to see how close you have it and tweak accordingly. Not everyone wants to make it the same, but they want the compensation to be just enough to give them a more even and manageable feel, but leave a little more in reserve for times that they want it. That suits some pilots so that they can manage high winds more aggressively, for example.

vbortone

My Feedback: (2)

Ed,

Thanks. I was looking for a procedure to adjust the throttle tech. I am wondering now if I will be interesting to preserve the cruise power at 1/2 stick position during the whole fly than the maximum power. I will assume that adjusting the maximum will get it close.

Thanks,

OhD

Hi Ed,

I'm in the process of installing a Throttle-Tech with a Jeti Mezon/Neu/Contra. I've read your comments regarding linearity and I'm wondering how you measured it? When I look at PWM to the motor vs. throttle stick position, it looks just like my throttle curve in my transmitter, so I assume everything else is linear. Obviously, the power out is not linear because I need a throttle curve to get midrange linear power. From your response above, I infer that somehow the Throttle-Tech will change the midrange in a non linear fashion, as you recommend starting with a linear throttle curve. It would seem to me if I only have one adjustment point and it is set for full throttle I will take what I get in the midrange and I will still need the throttle curve in the transmitter. What am I missing? Does the Throtlle-Tech introduce a curve similar to my transmitter throttle curve?

Regards, Jim O

vbortone

My Feedback: (2)

Hi Jim, I am using the same equipment. I won't be able to fly in the next two weeks. I flew with 70 and looks like it was too much. I reduced to 64 but it was extremely windy. It appears that is OK. I was planing to measure full power watts at the beginning and end of the fly. If power is close we are good to go. However, looks like is not the correct procedure. I will wait for you and Ed to figure out. Best,

NJRCFLYER2

My Feedback: (42)

Jim:

I was referring to the power out linearity. I've measured static RPM and power developed, not PWM response linearity. The reason for recommending the selection of a linear ESC response is so that the adjustment of the throttle curve is done in just one place as you correctly suggest.

Throttle-Tech doesn't introduce a throttle curve. It's adapting the output to the ESC as a de-rated response that is influenced by the motor battery voltage. It's a smoothly integrated response, diminishing the percentage of compensation as the throttle is reduced, eventually down to zero compensation as the throttle pulse width reaches the low throttle setpoint. If you look at the pulse width to the ESC along the throttle curve as the motor battery is used up, it's just shifting up as a parallel curve, as closely as possible since it's a feed forward system.

So just go with "linear" in the ESC, whatever that turns out to be, so that you're not fighting an artificial curve being introduced in the ESC software, and then adjust the curve from the transmitter with Throttle-Tech actively in the throttle signal path. You should see that you get a very similar power response throughout the usable battery capacity, i.e., that Tx curve ought to be fairly well preserved.

Adjusting the compensation factor is really the main lever that you want to pull to get the transmitter throttle curve you set to be as closely preserved as possible throughout the battery discharge curve. It's going to vary based on motor selection and to lesser degree, prop selection. I've received feedback that starting with 70 is too high with the Jeti, and 40 is more like it, but with the Hacker Q80-13XS that I have, 70 as a starting point is reasonable. I recommend getting the right compensation factor sorted out for your setup before trying to fine tune the throttle curve in the transmitter. Please stay in touch about your experience with this.

Best regards,
Ed

OhD

Okay, I believe I understand the operation and I can see why I might need a slightly different throttle curve with and without the Throttle-Tech. Will keep you posted on test results.

Jim O

Malcolm H

Jim, I think you will find the compensation factor you end up with will depend a lot on your Contra setup. Over here in Europe a lot of people use the 10.19:1 gear set and the 22x20/22x18 mixed props. Flying this is a lot like driving your car in low gear, you have a model with a very narrow speed range but huge pulling power. Using TP 5000 mAHr batteries I find I have around 28% capacity left after a windless P15 flight dropping to around 20% in the wind. More importantly I find almost no drop off in performance or cruise throttle stick position throughout a flight.

I suspect the drop off would be much more noticeable on a higher pitch setup. I have a couple of Throttle Tech units but as we are in the middle of huge contest season not a lot of time to play with them. Would appreciate knowing your findings and setup as I too use a Jeti/Neu combo.

Malcolm

OhD

Malcolm, I like the low gear concept, but when I bought the Contra a few years ago there was talk about them being too slow so I went for the 9.89:1 gear ratio. About the same time the guys were trimming the props down and I started with the smaller APCs and now run Brenner's version of those. A good part of this decision was to conserve battery consumption. I have had a few guys tell me I'm flying too fast and a few who are really saying the same thing when I do fly slow, and they tell me how good it looks.

I recently set up my Jeti transmitter to give voice announcements of the throttle stick position. After one flight I turned it off, as it was constantly talking. That got me thinking, maybe I am moving the throttle too much all the time. Anyway, I have finally got the plane flying well and I need to improve my throttle management. I'm hoping the Throttle -Tech will assist in that department. With luck, I'll report back in a few days.

Jim O

OhD

Well Malcolm, I wouldn't wait.

I flew the Throttle-Tech (t-t) yesterday and was very pleased with the results. My setup uses the Jeti Mezon 90 with telemetering, the Neu F3A, and the Contra with 9.89 gear ratio. Props are 20x22.5 on the back and 20.5x20.5 on the front. Without the t-t the indicated rpm is 4107 at 73 amps at full throttle. ( the Mezon is set for a gear ratio of 9.9) Based on bench tests, I set the t-t to a value of 50 but guessed that might limit the power too much so I was prepared to change it between flights.

On the first flight I was surprised to find it would climb straight up at 3593 rpm and 48 Amps early in flight and happy to see 3585 rpm and 48 Amps near the end. The battery had dropped from 38.3 to 35.8 and it only lost 8 rpm. During the climb at the end of flight the PWM duty cycle to the motor was only 86% so the t-t was still limiting the rpm meaning the system had lots of margin. I flew with that setting again while a friend watched, and we decided it could stand a little more power. The results were similar to the first flight.

I then set the t-t to a value of 40 and flew two more flights. On the early vertical climb it registered 3784 rpm at 54 Amps and late in flight it was 3758 at 55 amps. The voltage had dropped from 38.4 to 35.5 and the duty cycle was still only 91%. This was looking good.

I then flew a compact P-15 schedule and really liked how it felt and after looking at the data felt even better. I found that I had used essentially full throttle on every maneuver that involved climbing and never went too fast or too slow. On top of the Golf Ball the rpm was 3736 at 54 Amps with a voltage of 37.3. Cold battery? In the Top Hat rpm was 3765 at 53 amps and in the Avalanche it was 3769 at 54 amps. The pack was now at 35.4Volts. And the bonus was, I only used 2462 mAh for the flight.

So here are my conclusions:

The t-t does what it claims to do, that is, provides an essentially constant power for a given stick position (and load) throughout the flight, to compensate for the battery voltage dropping.
It allows you to set an optimum power that provides what you require while limiting the current, thereby reducing battery energy consumption.
It allows you to set this power at full stick so you don't need to mentally compute where to put the stick based on your estimate of the plane's speed. This will make throttle management much easier.

One of the guys called F3A Unlimited from the field and ordered two units.

Now I'm wondering if the higher gear ratio and big diameter props might make my plane even better? And maybe a 4000 mAh pack?

Jim O

serious power

Hi Jim,
Good work.
The voltages you give are, I assume , under load voltages !?
Also we have stuck with the 22x18 front and 22x20 rear c/w the 10.15 gear set - can see no reason to change from this set up.
Can't wait to try the tt.

Brian

OhD

Yes the voltages are under load, the data is logged in the transmitter during flight and displayed like a strip chart on the computer. I pick a point in time where the throttle stick is at full throttle and read the rpm, current, voltage and PWM duty cycle percentage. So for example, during the Avalanche above, the 3769 rpm, 54 Amps, and 35.4 volts all occurred at the same time. The PWM was 91% so there was still margin for an even lower battery voltage. I'll try to get a screen shot. I always have to learn how to do it all over on a Windows machine each time I try. Maybe next time out I'll see what happens after I use 4000 mAh. Anything else you can think of to test this thing?

It will be interesting to see how it works on your Contra setups with the big props. I tested in fairly light wind and I can foresee that it would be nice to easily change the setting when the wind demands it. Ed, are you listening? How about changing the setting with another channel from the transmitter?

Jim O

NJRCFLYER2

My Feedback: (42)

Jim, I've considered that feature and it would be easy to do. I've resisted up to this point since it could possibly be used as a way to get around noise test results. So can the transmitter ATV, but I was trying to keep this as pure and uncontroversial as possible. This doesn't mean you can't still use a switch to select a different throttle curve at the Tx level. Throttle-Tech won't care and it saves a connector.

danamania

Now up to 3 Throttle-Tech equipped models and the beauty is truly in its simplicity. Set-it and forget it (or just leave it set to the defaults if they work for you). Then just fly any throttle curve that suites one's flying style and/or the conditions, forgetting about the T-T while concentrating on the task at hand. The throttle stick feels exactly the same at the end of the flight as it does at the beginning; no need to baby the power early on to have Volts left at the end of the flight: Just fly the sequence as one would with any IC powered model. It's that simple, an elegant solution, and the best invention since the ESC for electric flying. With the bonus of having visual confirmation that one's Rx voltage is adequate and have loaded a fully charged LiPo (or a warning that one has loaded a spent pack)! It will save many pilots' bacon over time for that feature alone. These are going into any new electric of mine that's worth assembling and flying from now on, love 'em!

OhD

Ed: I should have thought of that. Truth is, I probably would never use it as I go home if it gets too windy.

Brian: I have attached a screen shot of the flight data. I can move the cursor to any time in the flight by dragging the little airplane at the bottom of the screen. Pretty neat system.

Jim O

Malcolm H

Hi Jim,

Great info! I'm afraid if you lived here in Scotland you wouldn't fly at all because it's nearly always windy. At our contest last week the wind was 17 mph gusting 25+ but everyone coped very well.

As Brian has said we all tend to use the slower Contra setup here and I will report back once I get a chance to try the Throttle Tech on it.

Malcolm