FxRES April 2022 2m F3L/F5-RES Monthly Duration Challenge

[AnthonyB]

I now think my time was longer, because it looks like I dived from 4m in 1 second, where it actually took longer.

(There are no brakes) Landing is done in speed mode 2 (more authority) and I let it sink, then pull back on stick, you can see to 2 "bumps" before landing. The actual landing is done by skimming the ground. As there is no mass, it slows up fastish. 

I can assure you it is still in one piece. As I said, I am still working out how it all works. I (also) think the above was (about) flight 50 and it is taking my abuse well !

[cirrusRC]

Yes I agree, the graphing sucks, for clear timings.   I resort to timing on tx also.

Definitely we should be including launch phase on all charts, so we can see motor run and launch height etc. 

[AnthonyB]

6 minutes ago, cirrusRC said:

Yes I agree, the graphing sucks, for clear timings.   I resort to timing on tx also.

Definitely we should be including launch phase on all charts, so we can see motor run and launch height etc. 

If you look back I was doing that, but it causes a long post - I am happy either way.

More interesting is the landing. I was in "speed mode 2" and to make headway against a strong  wind. The sink rate was 4.8m/sec.

You can clearly see the effect as I pulled back on the stick.

So who needs brakes ?

[martynk]

My preference is that the graph is used as an indication of the flight, I prefer a 'proper' timepiece to record the duration of the flight more accurately. I actually find the graphs very interesting, trying to fathom out what is actually happening and when. I suspect that most of the sinky bits are when a pilot is trying to get back upwind but appreciate that is not always the case.

 

Anyway, nice flight Anthony,  updated table:

 

     

 

[AnthonyB]

“My preference is that the graph is used as an indication of the flight, I prefer a 'proper' timepiece to record the duration of the flight more accurately.”

 

I cannot agree, for a “postal” comp. A photo of a stop watch does not cut it for me.

When flying alone, the moment of launch is a bit busy to be messing with a stop watch. My Mpx has 3 timers, but there is no permanent record of the flight, nor that it was a flight.

I did a few thousand 10min flights. That is – from the moment it leaves your hand, to the instant it touches down, with a record. I used a “talking timer” and that was set to 10:10. With the stopwatch started, you start the motor at 10:02 and that gives a release at 10:00. The flight log is the ONLY way you can have a permanent record that a flight took place.

The log is “awkward” because if it is a complete log (from switch on to switch off) a few seconds either way cannot be seen. So first you have to define the flight, and as it is from 20 sec after motor start, NOT from where the motor cuts, I display from that point.

I spent a few years doing 10min flights. That's 10mins where every second counts. At a conventional comp, a 3rd party does all the timing and writes it down. In a postal, there is probably no 3rd party, so it has to be the log. (At some comps, I would love to have seen the logs, because they were not based on reality).

So I flew by a talking timer, but used the log. The timing of the 2 was always perfect – both timings were the same.

In the past I have added all my work to the exam sheet, which can make a confusing report (if done by me).

(woops – better add) The software for both Altis and RC Electronics understands all these problems and so has a “magnify” function, so you can have precision to parts of a second – it is exact and does not rely on a 3rd party to get it right.

So – a log is the only way to be spot on. The actual full log is really the only way........... This is for fun, so who cares ?

Well in this cynical world we are now in – I will be as clear as possible.

Here is from switch on, to motor on, to launch. Note there is a good 2sec between motor on and launch.

Landings can be a problem to log / evaluate. In a just “how long” setting (like here), I would NEVER use the brakes and gently float in. In a set time situation, drifting just above the ground is not satisfactory, it has to be precise. Hence I changed style to – 20m up, 20m away and 20sec to go. This was done with as much crow brake as possible, and it becomes really clear on a chart the exact moment of touch down.

So, here we are. I prefer to use the flight log, chopped to show the exact flight, from the rules. You can just use a 3rd party and a stopwatch. I think "mates" can get slightly biased................ Just more of my rambling thoughts.

[StraightEdge]

I'm not too troubled by this.  For me the log is interesting as a graphic record of a good duration challenge flight, but I always hit the timer switch on the TX a moment after I ping off the bungee, then knock it off a moment after touchdown - and that's the time I record.  If there's a second or so of error either way, then it is of no real consequence in 99.9% of the monthly challenges.

In a comp setting everyone flying off the bungee is going to be timed by someone else.  It's more complicated with electric-launch I accept, but don't know for F5-RES comps whether the scoring will be done using stopwatches or by interrogating everyone's Altis data?

[AnthonyB]

The flight above terminated at 10:28.

The launch, not motor on, was at (about) 00:27 and so the flight was 9:59....... No dispute.

[AnthonyB]

StraightEdge ........ None is really that important. You say you flick the switch - at the moment of ping is a bit busy for me.... Whatever you like.

In a "real" comp, the pilot says (to timer) motor on in -  " 3  -   2  -  1" and that's the start. The watch is stopped upon landing and 20sec are deducted. If the CD does that, then it is the same.

(again) It is just for fun. I will do over 100 flights per month. If I do a good one, it goes here (even not so good).

The problem is that it has become a strange world and cynics seem to rule. So I prefer my flights to be precise and provable.

 

[Stewart Walker]

Had a few goes this afternoon, prop brake now works, times still rubbish, Graphs below, can anyone explain why in flights 31 and 37 the motor cut well before any of the time/altitude settings.

 

Thanks

[AnthonyB]

Stuart, you are climbing at >6m/sec   -   You are doing the 60m in 10 seconds. This is also giving a good zoom - which is deemed good !!

It could be that you are dropping the battery voltage too low because of  high power....... But that is a function of the esc and not the AMRT, or so I would think !

This is where I cut the throttle and did not wait for the switch........ One line

 

This is where the switch cut and then I closed the throttle - 2 lines .......... Please check yours.

[Stewart Walker]

Hi, thanks for the reply and advice, went back to the graphs and removed the altitude and added the motor input and output signals, looks like the ESC is cutting the power, maybe because its only 12amp and I'm overloading it, dont think its the battery because I managed good climbs on subsequent flights. I'll have a play with it on the ground and see what needs doing, thanks again

[AnthonyB]

Didn't  think about esc - I usually have double the needed capacity.

[AnthonyB]

I think you are on 7 x 4.5 ........ Measure the true size.

You can easily get to 7.5 x 4.5 without seeing it.

[StraightEdge]

If you have a watt-meter and can measure the max static load on the work-bench, what does it read?

I'd be more comfortable with a 20A ESC - gives you loads spare.

I'd also put the throttle on a slider rather than a switch, so you can modulate just how much power you need.

[Stewart Walker]

I've done 8 static runs on 2 batteries, lowest voltage was 10.5v, load was about 7.8A 90w, prop dia is 7.75", batteries are just warm to the touch, motor was to hot to touch after 8 2min runs. Can't get it to reproduce the early cutout. I'll go back to flying to see what happens.

Apologies to Martyn for clogging his monthly postal thread, I'll post any new comments on a new thread

[StraightEdge]

Stewart, your figures aren't much different to a static test I did using an ADH300L motor on a 9"x5" prop with a 3s 450mAh battery, where the peaks were 10.1v, 8.4A, 85W.  But how much the current draw differs with a model moving in the air I don't know?

Is it possible that your previous early cutouts were a wiring/vibration issue?  Or programming?

Jon

PS I know it drifts from the thread subject, but as your posts are already here I for one don't mind if they stay here.  Alternatively, if you post under https://www.barcs.co.uk/forums/forum/47-electric-soaring-and-f5j/ you might get a broader range of responses.

 

[martynk]

On 12/04/2022 at 16:31, Stewart Walker said:

 

Apologies to Martyn for clogging his monthly postal thread, I'll post any new comments on a new thread

 

No problems at all. Historically, these postal posts have always been full of chat.  

[AnthonyB]

My best flight this morning was a frustrating 22:23. That does not beat my entry I did earlier - but interesting.

I will discuss on the channel I opened, so not to bung this up.

[Graham Lorimer]

Another day at Fish Meadow, some reasonable lift in the morning, nothing after 2.30.

Problems with my Purito (motor burnt out on first flight of the day) and Magic 2 did a 7 minute flight first time up, and landed just in the field but a long way downwind. Long walk to retrieve the model, back to the launch point, and no motor function.

Assembled Circle Dancer (third and final choice for the day) and had about 25 flights, (without any further failures), with a best flight of 18 minutes 42 Seconds.

Now back to the workshop to investigate the failures. I do know that I am extracting more than the recommended Watts out of the DYS Motor, and it has done many many flights, so I guess at just £12.50 I can not complain if it has failed.

Further investigation has now shown that one motor wire on the Magic 2 has come loose, all fixed now .......... and the motor and ESC were blown in the Purito, spares used and ready to go again. Will put a smaller prop on the Purito to try and stop these failures.

Fish Meadow

Circle Dancer 18 minutes 42 seconds

[martynk]

Quite a selection..

Updated table