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Author Topic: E-36 "Puzzle"  (Read 14303 times)
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Tapio Linkosalo
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« Reply #100 on: February 13, 2017, 05:07:09 AM »


Yes, it was a learning experience. So far I have considered that my model wings should be strong enough to withstand a full-speed immediate DT. Turned out that the wings were, but the 3mm pultruded carbon wing joiner was not! OK, the model was flying barrel rolls, so it was facing downwards half of the time. Anyway I now need to consider if I would have to re-do the RDT procedure. Maybe add a delay of 1 to 2 seconds from motor cut to DT? But then again, on some cases that delay might turn out to be too much... I would not go the route of "one push cutting the motor, the other DT'ing the model", as that would provide an option to cheating - if your climb is going bad, abort the climb and move to glide phase with radio control! There are no specific rules banning that I think but definitely it is not in the "spirit" of the RDT rules.
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« Reply #101 on: February 13, 2017, 11:41:07 AM »

Tapio,
Regarding the "double press RDT method". Clearly the double press is an invitation to cheat as you point out. Here in the USA that issue is covered by the AMA rules. Any use of radio must terminate the flight and that the flight time is official regardless of duration. The FAI rules are less clear yet state that RDT can only be used to terminate flight. The difference is that the FAI rules allow an attempt score if the flight time is less than 20 seconds.
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Tapio Linkosalo
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« Reply #102 on: February 13, 2017, 12:47:19 PM »


Correct. F1Q rules read "F1Q models may use radio control only for irreversible actions to control dethermalisation of the model. This may include stopping the motor if it is still running." I recalled that there is the "irreversible function", however was not sure that also "to control the dethermalisation" was included. So that excludes the "two button DT", as you may cut the motor together with DT, bt you are not allowed to cut motor only.

For what it is worth, F1S rules do not say anything about RDT... IN the chapter for model characteristics (where F1Q also defines the use o RDT) the F1S rules say that "the same applies to the batteries", but do not mention RDT.
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rivers
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« Reply #103 on: February 13, 2017, 02:43:27 PM »

Tapio,
I read the F1S rules to be the same as F1Q regarding the use of radio. All the rules in paragraph 3.Q.2 apply to F1S....
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Tapio Linkosalo
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« Reply #104 on: February 14, 2017, 12:50:18 AM »

Ok, let me do some nitpicking. In F1Q, the RDT rules are indeed in paragraph 3.Q.2.
Quote
3.Q.2. Characteristics
<snip - I do not copy it all as it also describes the energy limiters...>
F1Q models may use radio control only for irreversible actions to control dethermalisation of the model. This may include stopping the motor if it is still running.
For F1S, this paragraph reads:
Quote
3.S.2 Characteristic
Nickel Cadmium (NiCad), Nickel Metal Hydrate (NiMH) and Lithium (Li) batteries can be used. Only 2 cell Lithium batteries or up to 6 cell Nickel cells can be used. Other battery related specifications in 3.Q.2 apply.
Maximum duration of motor run .................................... 10 seconds during the regular flights.
Minimum weight ........................................................... 120 g
Maximum wing span ..................................................... 91.44 cm (36 inches)
The number of models eligible for entry by each competitor is three.

So the rules state that the battery related specification of Q apply to S!

Finally, let's see the general rules for FF:
Quote
B.1.2.1 Category F1 - Free Flight
a) This is a flight during which there exists no physical connection between the model aircraft and the competitor or his helper. Radio control functions are allowed only when specifically stated in the rules for the relevant class. Closed loop control systems with active sensors and operating aerodynamic flight controls or moving mass are not allowed, unless allowed in the class rules.

So I conclude that RDT is not allowed in F1S, as there is no specific mention of it in the rules! (Hopefully there is still time to fix this in the spring meeting of CIAM?)



While on the subject, the rules for the motor run are also ambiguous, they only state that the moximum motor run is 10 seconds. I feel that the rules should read that the motor run is from launch to prop stop, and that the time can be measured either in flight, or statically. The latter should make testing the eligible run a bit easier than trying to see the prop turning high above...
« Last Edit: February 14, 2017, 01:05:24 AM by Tapio Linkosalo » Logged
danberry
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« Reply #105 on: February 19, 2017, 09:20:17 PM »

Well, I would argue that RDT is legal now and would have been fifty years.
With a caveat-----
After a max, what happens to the plane has no bearing on the score. RDT after a max is no concern for the timekeeper or CD.

In AMA events, when the RDT is used, the score must count. You cannot RDT and get down for an attempt.
I thought the FAI rules addressed this after realizing that allowing RDT to get in for an attempt isn't a really terrific idea but I must admit that I don't follow FAI rules very close.
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Starduster
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« Reply #106 on: February 20, 2017, 05:38:48 PM »

Well, I would argue that RDT is legal now and would have been fifty years.
With a caveat-----
After a max, what happens to the plane has no bearing on the score. RDT after a max is no concern for the timekeeper or CD.

100% Disagree!

Using this same logic, after the max occurs, I could pick up my 3 channel R/C, start up the motor and fly the airplane back to the launch point.

I personally think this is a great idea, and should be legal, but I double-dog dare you to try it at a contest!



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danberry
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« Reply #107 on: February 20, 2017, 07:26:48 PM »

Well, I would argue that RDT is legal now and would have been fifty years.
With a caveat-----
After a max, what happens to the plane has no bearing on the score. RDT after a max is no concern for the timekeeper or CD.

100% Disagree!

Using this same logic, after the max occurs, I could pick up my 3 channel R/C, start up the motor and fly the airplane back to the launch point.

I personally think this is a great idea, and should be legal, but I double-dog dare you to try it at a contest!





Yes, you could do that. You probably would still need to go downwind to get it.
And... with all that extra weight you would be solidly in last place.
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Tapio Linkosalo
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« Reply #108 on: February 21, 2017, 12:45:23 AM »


Cannot comment on AMA rules, but for FAI (as quoted above) the rules are clear. RC is only allowed when specifically mentioned in the class rules. For F1Q (and many others) there is a mention that RC can be used for DT purposes only, and for F1S there is no mention whatsoever. So in F1S the RDT is not allowed, and in no FAI class can you use RC to fly the model back to flightline after max.
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Starduster
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« Reply #109 on: February 21, 2017, 07:34:36 AM »

AMA Sporting Code, Outdoor Free Flight, 2017- 2018, Section 1, Paragraph 2 (Page 1: https://www.modelaircraft.org/files/OutoorFreeFlight2017-2018.pdf )

"2. General.
A Free Flight model airplane is flown without controlling or guideline(s) and
without any control of functions by radio except that the de-thermalizer function
may be radio operated from the ground by the contestant..."

I dunno, seems pretty clear to me, but what do I know? No mention of before, after or during the max flight time.

But, like I said, I'm just a happy idiot...

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Tapio Linkosalo
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« Reply #110 on: February 21, 2017, 09:47:22 AM »


Besides, FF models are so slow that the idea of steering the model back headwind to the flight line after a max does not work. Just observe your model turning towards the wind in moderate wind conditions, it is already flying tail first downwind relative to the ground.
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BG
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« Reply #111 on: February 21, 2017, 10:31:31 AM »

Guys, We all know the spirit of the rule here. RDT is a reasonable tool for trimming and general DT duties. I can't imagine that it would be disallowed in F1S due to a lack of it being mentioned in the rules. In fact, I would decline to fly the class if it were disallowed. I am sure F1S will be flown with RDT like all of the other mini classes (F1G, F1H, F1J etc.).

I have sen a fair number of flights short DTed with RDT to prevent a crash. In a few cases the model was down within the 20 second limit and a reflight was made. I don't see this as an issue. To win you still need to pick good air, fly consistently, and win the flyoff. In the end a reflect due to RDT here or there is of very minor import.

So, why the heck are we getting wrapped around the axel on this issue?

BG
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Tapio Linkosalo
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« Reply #112 on: February 21, 2017, 10:41:47 AM »


I totally agree that DRT should be allowed for F1S, that is why I suggested that the CIAM took the issue on the agenda in the coming meeting and would change the rules accordingly. I also would vote yes in any contest, at the pilots meeting before the contest, if it was suggested that RDT is allowed to use in F1S despite the current rules.

The reason that I brought the subject up is that I have seen way too many classes, where you need to "understand the spirit of the rules" to build your models match them. The problem is that this undefined "spirit" is (slightly) different for each and every one of us. Therefore I am very strongly promoting that class rules should be written in great consideration and detail, so that there is no room for interpretation, but for any feature you can tell if it is allowed or not. That is just and fair for all.
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« Reply #113 on: February 21, 2017, 10:58:08 AM »

Yes the rules to F1S should be clear about RDT. I flew F1S at the Kiwi Cup and used RDT. In fact RDT is the only way to DT my plane with the chip i use on my timer. I don't see a problem.

I watched a couple of Stan Buddenbohm flights with his 10 second model. Performance was ridiculous and it's not even his best plane. Stan set a new E36 AMA record with 15 maxes. He didn't drop a max. He stopped flying because he wanted to fly something else.  His hot E36 does 3:10-3:20 on the 5 second engine run. Amazing!
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Derek
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« Reply #114 on: February 21, 2017, 11:30:41 AM »

Not only to my understanding the missing mention of RDT in the F1S FAI rules is a omission and not done purposely.
The best thing to do is to avert your FAI delegate to add the wording about RDT in F1S the same as in most other classes:

F1Q models may use radio control only for irreversible actions to control dethermalisation of the model. This may include stopping the motor if it is still running. Any malfunction or unintended operation of these functions is entirely at the risk of the competitor.

I already did it,
Urs

PS: never saw a CD disallowing RDT in any class
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che
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« Reply #115 on: March 16, 2017, 08:48:34 AM »

Yes RCDT should be allowable in any class for, er, DT and any other function is a trimming aid. I'm sure a jury would allow same if someone wanted to test the rules/be pedantic.

Like Tapio I have used timers that have a double action RCDT (engine then DT separately). This is great for trimming but, yes, may be questionable for contest flights. But as you are supposed to get your timekeeper to check your engine run (UK at least, and Scotland whilst we're still connected) then any short run could question the flight ?

One comment on the Forge E36 timer as developed in conjunction with Prof. John Thompson. This requires a transmitter that sends single pulses to the receiver or else multiple pulses may well stop the engine and DT in quick succession - not recommended. Unfortunately I think this means that the Bauer RCDT (hold the button for multiple transmit signals) and the Bodnar units (3 transmits per button press) can't be used with this timer. This is a great shame and perhaps needs to be looked at with, perhaps, a set delay between engine stop and DT signals being recognised; so if, say, 3s delay was enforced then perhaps these two popular units could be used.

CHE
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Tapio Linkosalo
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« Reply #116 on: March 16, 2017, 11:25:03 AM »


Just to make things straight: my timer/RDT setup does not allow for separate motor cut and DT, but they both happen at the same time from the same pulse. I consider re-programming my timer to have a short delay from motor cut to DT, as I recently folder my wing joiner when DTing a model going wrong (the wing withstood the DT ok, but 3 mm carbon joiner broke). A second or two of slow-down time would spare the airframe.

Also, I prefer the term RDT (as suggested by Ken Bauer). Radio DT, not Radio Control!

 
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che
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« Reply #117 on: March 17, 2017, 05:27:25 AM »

So what controls the DT in case of R(C)DT ? The radio does, hence it's radio controlled DT isn't it ?

And isn't stopping the engine an irreversible action - just wondering.

CHE

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« Reply #118 on: March 17, 2017, 11:41:23 PM »

I think the term "control" implies more than just a single non-reversible action. Hence I'd agree that Radio DT fits better than Radio Control DT. You could make a case for "radio activated" or "radio triggered".

Tmat
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Tapio Linkosalo
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« Reply #119 on: March 18, 2017, 01:22:56 AM »


Exactly my thoughts too, Tony. Of course you can argue that triggering the DT (and cutting the motor) is control, but in common use "radio control" refers models that need constant pilot input to remain airborne...
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« Reply #120 on: March 18, 2017, 06:37:24 AM »

Re CHE's observations on my Forge Electronics E36 Timer - John Thompson showed me two Bodnar RDTs - one of which gave a single pulse per button push (good range but not 'instant' acting) and a second one which gave 3 pulses per button push (with less range but 'instant') - so it depends which of those types you have as to their suitability. I can't comment on the Bauer unit, but anyone having the specification of the RDTtrip pulses from the Bauer unit is welcome to contact me and I can check it's functional compatibility with my timer (ignoring the multiple pulses issue - but see next paragraph) 

However John's idea of being able to stop the motor was only for use in trimming flights as during a competition flight he states that BMFA rules only allow a single transmission to the model. Thus my timer can be user configured to only accept an RDT transmission during the glide phase - so either of the Bodnar units would work equally well in this case (and maybe the Bauer)

Again I'm told that in the event of a launch going badly wrong, some fixed delay between motor kill and DT will only work to save the model in a particular circumstance, whereas allowing the user to choose the moment to DT following a previous motor kill gives a much better chance of saving the model.

Alan
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« Reply #121 on: March 18, 2017, 12:14:13 PM »

Alan,

Thanks for commenting on my comment on your Forge timer.

I had a look at your website and noticed the issues with single or multiple pulses but please correct me if I'm wrong but a user CAN configure an engine cut separate from a DT using the correct RCDT (or RDT or RADT or RTDT, depending on which country you live in) - is that correct ?

If so then the necessity to use just a single pulse transmission is not a good one as there is no quarantine that this single pulse will operate the required function. This is why the Bauer RCDT, Fx, Multiclass and many others will transmit multiple times; basically to ensure the signal gets through.

I'm sure there is a simple software change that would enable multiple pulses to be ignored in these trimming cases which would give your timer better access to flyers using those RCDT units. I for one think the option to stop the engine separate from the DT is so useful for trimming that I wouldn't leave home without it.

CHE
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« Reply #122 on: March 18, 2017, 06:55:35 PM »

Che

Rather than replying just yes or no, for clarity I'll try and summarise the situation - read it carefully distinguishing between the words PUSH and PULSE !

Motor & DT OPTION  (single pulse per RDT TX button push)
If motor is running, first push stops it. Second push operates DT. If motor run was completed, first push operates the DT.

Motor & DT OPTION (multiple pulses per single push of RDT TX button)
If motor is running a single push will stop the motor and, at some interval later determined by the RDT pulse repetition rate, operate the DT. If motor run was completed, a single push operates the DT.
 
DT only OPTION
either single or multiple pulses from the RDT RX will operate the DT only

I have no knowledge of the internal workings of other RDT compatible timers that may be in use, but note your statement about the quoted RDT systems issuing multiple pulses "to make sure the signal gets through" - another interpretation of that statement could be "to make sure the timer has a chance to see the signal" - just suppose (though I may be wrong) those timers software have a housekeeping loop running at 20mSec (to keep refreshing the ESC and DT servo at the correct rate) which checks for an RDT pulse once somewhere in that 20mSec loop, then a short RDT pulse could get missed (eg the Aeris is 5mSec)  whereas the Bodnar pulse is 100mSec so the timer would have 5 chances to spot the pulse. That was how I made my prototype as no data on the Aeris site told me the pulse was only 5mSec long - the short Aeris pulse was only discovered during testing with John Thompson's Aeris unit! So I adapted my design such that RDT pulse detection is handled by a software interrupt so it responds almost instantaneously - no chance now of missing an asynchronously emitted short pulse.

Alternatively I recognise that an RDT system intended to be used up to say 5 minutes after launch may have a reception issue at that range and the designers chose to issue multiple pulses for that reason, but I'd prefer not to use such a system if the designers doubt its range integrity and seek to mitigate a range problem this way. If someone can offer a valid alternative explanation I'd gladly eat humble pie!

A software change that for example considers 3 pulses to be a single button activation is possible but what if one of the three "doesn't get through" as you are apparently convinced that some pulses *can* go missing ? (your justification for the multiple pulsing). Neither would such a change suit the Aeris or the Bodnar single pulse variant for example.

And suppose I did your software mod - here's another problem. The Bodnar triple pulse variant issues its three pulses at 0.5 sec intervals, so an untrimmed model behaving dangerously (to itself or spectators) would continue to be powered for a further 1.5 secs after pushing the button in panic to kill the motor.

I appreciate that you acknowledge the usefulness of this option to be able to stop the motor during trimming flights - but if that feature is to be accessible to flyers using the multiple transmission RDT systems I think we would need to customise the timer software for every RDT system in the market. Validation testing without access to these systems (you can't afford me to buy one of each!) would be problematical too.

However, just to emphasize it again for those losing the will to live after reading my lengthy explanation -single or multiple pulse RDT systems are fine for use with my timer if the RDT input has been configured to operate the DT only.

Best regards

Alan
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« Reply #123 on: March 20, 2017, 06:07:13 AM »

Thanks Alan, an extremely useful description of some RCDT issues and how your timer deals with them.

There are some timers that have the double DT option (motor + DT) that work fine with multi-pulse systems so I guess there is a way to configure the software to ignore the 'extra' pulses, however, I understand your rationale for not doing that.

I hope the timer sells, it's a nice system.

And apologies to Tapio for semi-high-jacking his thread - it's about his model after all.

CHE
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« Reply #124 on: March 20, 2017, 04:38:08 PM »

CHE

OK, I've been thinking about how best to address these various issues, but it might be worth discussing this first - "when is a single pulse NOT a single pulse?" Answer:- A Bodnar single pulse is issued at some random time up to 2.5 seconds after pressing the TX button (so the average delay is 1.25secs) but if you continue holding the button pressed then 2.5 secs after the first pulse another (single) pulse will be emitted and so on, until the battery is flat or your finger falls off. Obviously releasing the button following the first pulse being sent stops this continual slow pulsing. However holding the button down indefinitely on an Aeris TX results in just one pulse. The button has to be released to 'prime' it for a subsequent pulse to be sent. I have no knowledge of the Bauer or other systems you mention so cannot comment until someone wants to fill me in on *precisely* how those systems issue their trip pulse(s). The sort of data I need is unlikely to be on websites or spec sheets, it needs measuring with an oscilloscope - which I had to do for the Aeris and both of the Bodnar systems.

What I would propose for my timer is to offer two different versions because I feel my work-around for a multi-pulse system would compromise the responsiveness of the timer in dealing with the preferred single pulse systems (see later) but I remain receptive to any better suggestions. The standard timer stays as it is and a further version might work as follows. We only need consider dual trip operation (motor & DT) with a multi-pulse RX in this case.

The timer will stop the motor on very first pulse detected - this might be the second or third issued if you still really believe that they might not get through - but considering the model has just been launched and is only seconds away (the motor is still running after all!) if a pulse doesn't get through now, how on earth can it be expected to DT a model that is two or three minutes downwind? So, having stopped the motor on the first pulse seen, the timer now ignores any number of further pulses for a certain time period to ensure the last of the multiple pulses has been issued. This period might be 3 seconds for example - but you multi-pulse system users will have to tell me what this 'deafness' period needs to be for your system and on your heads be it of you get it wrong. The DT would occur at some later time following that 3(?) second delay when the user activates his TX again and the timer receives the first pulse of a the next multi-pulse group.

The Prof and I don't consider this to be a prudent way of operating as we would hope that anyone flying a model which has misbehaved and is heading straight towards us would chose to go 'click' 'click' and certainly destroy their model before it hits us rather than go 'click', pause 2 seconds . . . . . whoops, sorry gents . . . . . pause 1 second, 'click'

Finally for a bit of light relief, I have to ask if a multi-pulse system is compliant with the rules anyway as only a single transmission may be made to the model - and three pulses equals three transmissions if you are a Formula 1 Motor Racing Team seeking to disqualify a competitor on a technicality which though it complies with the spirit of the law actually breaks the letter of the law - lets have some fun with this!

Best regards

Alan
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