I cannot understand what is weird by someone taking over a Tx in an EMERGENCY situation. And this was mentioned in the context of the second, experienced, pilot who found that none of the controls were responding, eliminating the possibility of "the flier not being truthful".

The flier who lost his aircraft had adequate experience to be flying solo and the use of a buddy box does not arise in this case.

The weird part is a reference to the short time window.  I believe what remains is a model that has had a head first crash, and I am not sure if the second flyer got adequate time to be of any help in that short time frame.  Do we have confirmation that he had enough to check for control input before the model hit the dirt ?

Also, if the aircraft had a head first crash, I am not sure how confidently someone can determine if the linkage rods etc where binding/stuck etc in some stick positions.  While leaving open the possibility that there is defective equipment (after all it is all electronic components), I am still not sure if all common sense possibilities have been eliminated.

I will repeat that the question is not whether the second flier had time to recover but that he found no response to his inputs.

As I have said in my posts on this, the usual culprits have been eliminated. Was looking for inputs beyond that, things that our - local - collective "uncommon" sense may have overlooked.

And what I was trying to get clarification (obviously at the expense of getting on your nerves ) is whether the second person had enough time at all for verification of response to his inputs before the model hit the ground ? After all, it is a matter of seconds and fractions of seconds.

I would suggest that a foamy be flown a few times using the same receiver in the same location for the next few flights.

i have a question, did this happen to only this guy or most of the fliers experienced glitching that day or time 

Sushil,
I have  seen one such crash myself and have heard of 2 further crashes on FASST the most likely culprit in all the cases was receiver heating  and/or low voltage  resetting .
You might find some answers in this thread :
http://www.rcindia.org/radios-and-receivers/crash-on-futaba-fasst/

All these were attributable to the fact that the receiver did not have sufficient air flow over it .

Sai

Sai

Whatever. And if that is a likely cause on an overcast day then I think that FUTABA has a lemon. I just cannot fathom how and why a receiver should overheat. They do not need much power and the only possibility is the microprocessor is dissipating a lot of heat. It also seems to be a not uncommon problem.

Any which way, even if these incidents are isolated, they are indicative of a not fully developed technology. I also accept the advantage is in the impossibility of frequency clashes. But that, to me, is the only tangible "pro". The "cons" of these type of problems still outweigh that, in my opinion.

Sushil ,
This might be of interest to you :
http://www.aaccmac.org/documents/2.4FutabaCautionNotice.pdf

Sai

Ah, so that's the game being played    We have a huge thread already on why a receiver can over heat when servos go bad or when the linkages are stuck causing higher amp draw by the servos.  That, coupled with Futaba's poor choice of components with a 60celcius temperature tolerance does pose some risks unless you follow a few common sense best practices.  Still not a problem, unless you are careless in your setup.

I feel sad for all the people who risk their gassers, turbines, expensive helis and scale planes on the Futaba lemons (all the while they have access to many other 2.4 brands and technologies) !  And no clue why it is a major player (if not the major player) still in most fields around the world.

And there are other brands of 2.4 with no real issues reported in any sizable quantities at all yet (ala Airtronics), in case anyone feels adventurous enough to go for the tangible "pro" (without these "types of problems"). 

It always boils down to one crash, where people think they have investigated and eliminated every common possibility. And even when all such items are meticulously eliminated, it is not uncommon to have a single bad receiver.  What we seem to excel in is generalization.

PS: Where did I leave my list of the "types of problems" affecting 72Mhz ?

QuotePS: Where did I leave my list of the "types of problems" affecting 72Mhz ?

oh come on 72mhz or similar band are not that bad

Sahil - I have a synth 9C and a recently acquired 7C (got it for $60, from RCU classifieds ).

I am not against 72Mhz, and that was just a sarcastic reference. I converted from 72Mhz not too long ago, and still use it for buddy training etc.  But I hate these generalizations and scare mongering based on one off incidents.  Some people accuse me of the same when it comes to 72Mhz. But the distinction is very clear, that frequency interference on PPM/PCM is a 100% reproducible issue.  It is the major reason why 2.4 was invented in the first place.  Stating such a fact about Mhz and generalizing based on rare incidents about 2.4Ghz are two different things. 

I hated the stickied post on the other forum that scares people (who did not take the time to investigate, or newcomers) from using 2.4 technology. I wish these people tried some other brand of 2.4, in case they are not comfortable with Futaba or JR/Spektrum (something like Airtronics or Assan conversions); instead of blurting out generalizations.

QuoteSahil - I have a synth 9C and a recently acquired 7C (got it for $60, from RCU classifieds Wink).

for me this is the reason,now more then ever i want to stick to 72mhz or similar bands because for me its price that matters besides i will soon be getting my 9ch radio with built in synth n scanner almost near to WFSS (wireless frequency select system)so it should solve/avoid/warn major problems

also did you know there are radio system where in one can transmit on dual frequencies but this for DIY type,although i remember seeing similar commercial unit.

Anwar

With due respect to your objections, I would still like to enquire if the rx was in a nonventilated space away from all other heating devices (like batteries, esc's etc) and with no room for airflow over it ?

You see, the earlier reference to    http://www.aaccmac.org/documents/2.4FutabaCautionNotice.pdf

shows one how the Futabe Rx heat up on its own, and therefore a precautionery ensuring of air-flow over it, could mean all the difference. This is not to vindicate any arguments made here and in earlier posts elsewhere  but as an elementary precaution when working with these type of rxs'. It does not deride the fact that Futaba and Airtronics are sitting on some of the world's best model RC technologies, the difference being that Airtronics rxs', as noted by all sources of information, do not heat up. The JR/Spectrum 2.4Ghz is next in line and then comes others like  ASSAN and others.
This also does not mean that they are bad by any comparison. All these technologies have proven many times over in many airfields where typically there could be atleast 30 or more numbers of  2.4ghz fliers all working simultaneously in various assorted manners. Meaning to say they are all good technologies

But I am still looking forward to a little wedding....

Saju

Saju not again   
I would rather

Quote from: anwar on October 15, 2009, 01:11:26 PM
That, coupled with Futaba's poor choice of components with a 60celcius temperature tolerance does pose some risks unless you follow a few common sense best practices.  Still not a problem, unless you are careless in your setup.

Saju - That's for you I would suggest that you read that paper carefully to justify your "gets heated all by itself to 60C" argument (more like 72C per the article), unless of course, other events contribute, like high amp draws by stuck servos. I am tired of repeating this.

While reading, pay careful attention to phrases like "I am trying to represent is a model that has been left on a tarmac pit area in the sun on a summer’s day" and "How much current would a stalled servo consume".  The article says cooling is a good idea, which Futaba itself says when they recommend that the receiver should not be wrapped in foam.

Sai - Me too 

Quote from: mpsaju on October 15, 2009, 03:33:46 PM
I would still like to enquire if the rx was in a nonventilated space away from all other heating devices (like batteries, esc's etc) and with no room for airflow over it ?

Not sure about airflow (it is certainly a good thing, don't have enough data to say that is a requirement). But away from heat sources, right antenna orientation, and not wrapped in foam etc are issues to be clarified, and I believe they were all considered (as these are part of the "common" reasons).

Quotefrequency interference on PPM/PCM is a 100% reproducible issue.

The 100% reproducibility is exactly the point I have been trying to drive at. With the 2.4GHz problems there is only conjecture and uncertainty. This is the real issue.

Also, even if Futaba has issued an advisory, I consider it inadequate design if the radios cannot be used in a fairly typical environment in many countries. The same conditions do not affect other type of radios from working satisfactorily. I would also like to add that this would hold true for ANY manufacturer who dared to release a product with an inherent flaw.

Imagine a car manufacture issuing a caveat that, for example, it should not be used if there is more than 10mm of rain, or some such thing.

Basically, if one product and/or technology cannot work in the same manner, in common conditions as ALL OTHERS, then there is a flaw, and a deep one at that.

But we have drifted a bit and come down to Futaba specific problems because my report just happened to concern that brand. What about other 2.4GHz radios?

Anwar


Well what is bound to get heated gets heated when powered up whether you like it or not... Look at your standard PC... The Pentium chip for example gets heated up just doing the functions at high speed... The higher the speed the higher heat it dissipates and therefore the higher the efficiency of cooling one has to provide. The same thing goes here as well. This doesnt stop you using it.
The microprocessor (Micro-linear ML2724) has to do a formidable task of checking for blocked and unblocked frequency bands continuously at very high speeds and successfully transmits its signature in two of the free bands simultaneously in the Tx. The Rx also has a similar microprocessor running at high speed to unravel the signature from the right bands, authenticate it via the tx signature, decode it to the different channels at 1.5mbps.
The technology is superior, but with cautions... whether it is Futaba or not is not important, when it comes to Physics.

Cheerup man...

Quote from: sushil_anand on October 15, 2009, 04:35:43 PM
Basically, if one product and/or technology cannot work in the same manner, in common conditions as ALL OTHERS, then there is a flaw, and a deep one at that.

In common conditions, there is no issue, is what I have been trying to say all along.  Just make sure the receiver battery is strong, antenna orientation is OK, do not wrap the receiver in foam, and make sure your servos and linkages are setup right (not binding).  These are the simple rules everyone I know have been following for Futaba, and they have been fine so far, in the blazing hot conditions in Qatar (yes, NO one flies at noon in summer!). You may call that "lucky", but those are the facts.

Quote from: sushil_anand on October 15, 2009, 04:35:43 PM
But we have drifted a bit and come down to Futaba specific problems because my report just happened to concern that brand. What about other 2.4GHz radios?

I have said time and again that Futaba made a poor choice in terms of component selection, so that they missed an opportunity to accommodate an even wider range of temperatures and operating conditions (like people not following proper setup instructions). Again, this is not an issue for routine use.  Other brands are even more accommodative of such excursions.  Just try Airtronics 2.4, if Futaba 2.4 gives you sleepless nights   But there is no logical reason to completely bad mouth this technology, that is seeing wide-spread adoption.

But people just go on generalizing against the use of any kind of 2.4Ghz use, which defies and all common sense (and common sense of the majority of RC users who are already happily flying 2.4G !)  It seems that a conscious decision has been made to bad-mouth this technology, until the day arrives when they also buy a 2.4Ghz radio (for whatever reason ! I hope they all receive one as gifts from somebody who cannot take this anymore )

Anwar

I dont think any one is generalising here about 2.4Ghz use... There is no question about 2.4Ghz being good technology... Since Futaba came out with one of the first FHSS systems, they used an earlier processor which so happened to have this limitation on temperature. Others who came later skirted around this problem, their own way or use of later more advanced technology. This does not in any way deride 2.4Ghz or who ever use it, me included...

Saju

Quote from: mpsaju on October 15, 2009, 05:06:56 PM
This does not in any way deride 2.4Ghz or who ever use it, me included...

Unforunately Saju, that is not at all what I see from other posts here, and elsewhere. Just read through the posts here carefully.  You can find even more glaring examples elsewhere.

Time to put a lone sticky post on the "Radio" board which proclaims 2.4Ghz is more dangerous than the H1N1 flu

We are all intelligent enough to see that radio technologies and brands come and go. But having a closed mind on something that is being widely adopted begs for questioning.

PS: And my fingers are tired of questioning   

Ok, I am a little concerned here. We know that the Futaba Faast Rx is susceptible to problems due to heating. Now, wouldnt 6V battery pack (A123 even more ) , heat up the Rx ore than 4.8V ?
Also, if we use high torque digital servo with a huge current load, then wouldnt the Rx heat up ?
I noticed that the 14ch Rx was slightly warm even after a few minutes of just leaving it turned on with 6V .
I do abide by the guidelines with the Rx installation, but still i am a little unsure about the heating issue. How do others here plan to overcome this ? or do we all just ignore this and move on ?

Gaurav -

Like anything in life, do not do anything that you have second thoughts about.  But try to do your research first, so that you can draw your own meaningful conclusions. If you feel uncomfortable even after that, do NOT do it.

Ever since I became aware of the heat issue, I was looking at how people are dealing with it, and if this is affecting people's confidence in deploying this.  To my surprise, I found that more people who are flying the bigger models (especially gassers) were going for Futaba FASST as compared to any other radio !

I am not sure if Futaba would be my first choice, if I had know about the heat issue.  I always loved the ease with which they can be programmed, so I went for one.  But further reading made me comfortable enough to decide that for routine use, there is no real issue as long as I followed a few simple guidelines.  I would have been just as comfortable or even a bit more relaxed with a JR 2.4 system back then.

Newer receivers are coming to the market from Futaba, and I did not do much research on how much they have fixed the heat issue in those.  May be with the newer receivers, this whole issue is a non-issue ! After all, it is only the receivers that are the cause for concern.

They do have one of the best (if not the best) 2.4 systems in terms of interference handing capability (mostly due to FHSS), and that is probably why they are doing so well in the 2.4 market !

To directly answer you, the number of gasser flyers who use Futaba 2.4 is a good indication that you are safe.  There aren't any guarantees about most things in life, so hopefully you will not take me to court for saying what I just said  

Even the higher torque servos draw a safe level of current in normal use.  Only if they get stuck that they overdraw current and tend to cause issues.  The receivers are rated for 6V, so there should not be any cause of concern there too.

Quote from: gauravag on October 15, 2009, 11:31:50 PM
Ok, I am a little concerned here. We know that the Futaba Faast Rx is susceptible to problems due to heating. Now, wouldnt 6V battery pack (A123 even more ) , heat up the Rx ore than 4.8V ?
Also, if we use high torque digital servo with a huge current load, then wouldnt the Rx heat up ?
I noticed that the 14ch Rx was slightly warm even after a few minutes of just leaving it turned on with 6V .
I do abide by the guidelines with the Rx installation, but still i am a little unsure about the heating issue. How do others here plan to overcome this ? or do we all just ignore this and move on ?

Gaurav
Please note that most TTL based IC technology use 5v as a standard. The 4.8v spec given is the lowest value the ICs can tolerate. The higher value of 6v provided is just to provide a sort of protection from wrong polarity by way of a diode in series with the Rx main circuit. The forward bias drop of a silicon based diode is 0.7v. So if that is subtracted from 6v, we arrive bang on the std TTL voltage upper tolerance of 5.3v. Therefore providing 6v is a non-issue.

Abiding by the guide lines in terms of proper air circulation over the Rx to dissipate heat created by its processor is important and should be followed as a good measure. Doing so in a gasser or Glow engined plane is tricky as it could mean that some of the exhaust may get collected over the rx and its compartment, especially if the plane is of balsa construction. The other way could be use of a very small fan over the rx. If you are using high torque servos which draw high current, it is best to only connect its signal wire to the rx and connect the power wires to a junction board separately connected to the battery, thus not transferring the high current over the rx board copper. But then again one has to compromise depending on ones best judgement.

Gaurav ,
Not withstanding all the tech talk  for which i don't even need a helmet to avoid  it flies way over  

In simple language : Rx Heat is an issue with FASST that needs to be addressed as long as you  are  firstly aware of this issue and take adequate precaution  to ensure against failure due to it you are fine  .
You might have to undo some old habits and learn some new ones  but  what the heck that is adjustment to change  in any case  

Sai