f106jax

My Feedback: (16)

Having recently bought a Futaba 12FG with the 6014 2.4 receivers, I've been following the threads about high heat causing the receiver to go "off line". Is anyone aware of this situation happening with a turbine powered jet? The posts in the other threads all reference prop planes, I haven't noticed any mention of jet installations being affected. If it is not affecting jets, is it possible that the tailpipe augmenter is pulling enough air through the fuselage to keep the receiver cool enough to not exceed the shutoff temp?

Jetkopter

My Feedback: (1)

Mike, I think that most of the problems where with giant scale stuff, in hot climates like AZ. I know that the climate in PA around Liberty Bell can get pretty warm, but most of the jets dont have the sun beating down through the canopy and on to the rx. I have been flying the new futaba 6014 in several of my jets and have nothing but good things to say about it. I guess time will tell. See you soon.
Don

afterburner

My Feedback: (18)

From the info I've seen, the Rx shutdown is occurring at an ambient temp around 160+ degrees F. Seems to have happened in Arizona with aerobats where the Rx is sitting under a clear canopy in the desert sun. Just gotta keep a light towel over the canopy when not flying. I'm using the same setup you have and it has been working great. I can't even walk far enough during a low power range check to get a failsafe.

Marty

George

My Feedback: (57)

I just heard of this problem this weekend when I returned home and have been asking local flyers who fly the system if they have experienced anything or even heard of a problem; none have.

I've been flying my BC in AZ for the last six weeks with 6014 with no problems, but then again the hottest day I flew in was 98 degrees and the sun does not beat directly on the receiver for long periods of time (only when the canopy is off for charging, fueling or starting).

I'm currently switching two more jets over to FASST, so as Don siad, "time will tell".

George

f106jax

My Feedback: (16)

Thanks guys, glad to hear that the equipment is working good in our installations. Right now, my concern is about receiver flooding instead of overheating. When will the rain end?!

Looking forward to seeing you guys this summer.

mr_matt

My Feedback: (10)

Hi Mike,

In my experience (at my real job) the short answer to your question is a qualified "yes". Any movement of air around the receiver will help the situation tremendously.

In fact, if I had to bet I would say that when all the smoke clears, Futaba will have some sort of improved plastic case for the receivers, that either has more cooling slots and/or a built in "heat pipe" that mechanically couples to the most susceptible electronic components.

In my real job, thermal management is a huge issue. A convection cooled device like this receiver needs moving air around it to work. If you can improve the air movement (especially the air movement right around the most susceptible parts) you are doing great. My guess is Futaba will change the plastic RX case and put stronger words in the manual about mounting and airflow and that will be the end of it. Just a guess.

GrayUK

Guys.
On the temperature issue.
Lets look at what has been reported.
We have a handful of failures in Arizona and one or two others in very hot places.

All of the failures (as far as I can tell) are in large prop aerobatic models with large canopies and the rx’s in the canopy. Other flyers in hot areas such as Florida are flying jets with no issues reported

Reported failure temps of the RX body is 167 F. 75C.

This is not ambient air temp but the temp the rx has got to by radiant heating through large transparent or semi transparent canopies. Basically the greenhouse effect has cooked the rx. I also wonder if the large curved canopies are acting in some way as a lens and concentrating the suns energy (magnifying glass and paper!)

We also know from work done by a German guy called Jurgen that the temperature rise on an rx from above ambient by its own heat generation is nominally 9F or 5C.
So whatever the ambient temp of the air is we get another 9 of 5 to add to it.

So if the failure temp is 167F/75C without any radiant heating or greenhouse effect the rx can take an ambient temp of 158F or 70C.
Now this is bloody hot! Where in the world does it get to those temps naturally? (And would you be out flying?)

Just looking at the 70C for a moment and put it into context , the highest ever recorded temp on earth was 57.7 °C (135.9 °F) Al’Aziziyah,Libiya 13 Sept, 1922 (Ref: http://en.wikipedia.org/wiki/Extremes_on_Earth ) remember this is air temp and does not include greenhouse or concentrating effect behind plastic or glass covers.
For most of us in the world a very hot day is to 35C / 95 F if we go to extremes lets say 50C which is 122F we are still nowhere near the required ambient failure temp of 70C 158F. (The highest ever recorded temp in England / UK was 38.5C in 2003).

I did tests myself on two models, Hawk and L39.
The Hawk has a canopy floor and the RX is about 3 inches below that.
The monitor showed the ambient temp was 29C/84F
I placed the thermocouple on the rx body and recorded only a 1 degree rise in temp (without the rx on) to 30C/86F.
The L39 has an open canopy floor with the rx fitted to the side of the fuselage below what would be the canopy floor, so potentially it is worse than the Hawk.
Monitor showed the temp recorded at the rx 31C/87.8F. A rise of 2 C only (without the rx on). It can be seen that the lack of floor and the greenhouse effect has doubled the temp rise. (Very simplistic but you get the point).

Jet installations usually have the rx out of direct sunlight and radiant.
I agree that some radiant energy will still be present in the cockpit and that in turn will warm the structure etc.etc. But it is not going to get the rx up to the kind of temperatures needed to fail.

We know from other thread posts that Futaba are looking into this, but until they conclude, I see no reason why we should not all continue to fly, most without any changes and some of us with some minor alterations.
For the rest of us not living or flying in these extreme temps I propose that you just go and fly!
I did last weekend, all 3 FASST models (2 Jets and 1 Prop), one with a 14 channel rx, one with and 8 and one with a 6. All performed perfectly as normal and I had a great day.

Paul

mr_matt

My Feedback: (10)

Hi Paul,

For a pure convection cooled device, if their is no air movement, the receiver itself can self heat to the failure point, even at just a few watts. The question at hand is whether air movement helps, the answer is always "yes".

Solar loading is a big issue as well, do not put the unit "on the dash" so to speak (in a car, imagine almost any item left on the dashboard in hot weather).

To me the issue might be moot, the fact that Spektrum can survive in equivalent environmental conditions is a big marketing issue for Futaba. They need a real "solution" IMHO.


Boy it is great to not be a radio rep....very liberating :-)

f106jax

My Feedback: (16)

Hi Matt and Paul,

Thanks very much for the information and research. My plan is to mount the receiver with 2 narrow strips of Velcro placed along the edges of the receiver. This will create a "tunnel" between the bottom of the rx and the plate that it is mounted on. Hopefully that should help the receiver's generated heat disperse.

GrayUK

Matt Hi.

“For a pure convection cooled device, if their is no air movement, the receiver itself can self heat to the failure point, even at just a few watts.�

Agreed:
But for that to happen the rx would need to be very well insulated to stop conductive heat loss and have no path for ANY convection.

Solar loading is, I believe the real reason for the failures. I agree with you completely.

Spektrum still fails but 18F above FASST. (from the reported data i have seen)
With the solar loading from radiant, they too are vulnerable in that type of istallation. It may be that some of the reported mysterious failures on Spektrum could be attributed to this, I do not know, but it is possible.

I am not brand warring here, it is not necessary, Spektrum fails but at a slightly higher temp, I agree with you, I feel that this may be inherent with the 2.4 technology chip sets. I am not sure what Futaba (or Spektrum for that matter) can do about it, other than, as you say, improve ventilation for convection and offer much better guidance on installations.
A comment on another forum has suggested that the RX should be mounted on its side or even upside down. The chips that get the hottest are at the bottom of the rx, so it would definitely help with convective heat transfer. I feel this is all very unnecessary for the vast majority of us who will never see ambient temps as high as Arizona. But, a good install, is a good install anywhere in the world! It is not bad practice to ensure good airflow for cooling on ANY electronics. I think it is something we may have to get used to and consider more. I remember having to install valve receivers suspended on elastic bands….. soooo old…. [&o] [&o]

GrayUK

A good idea, makes sense and can not do any harm

mr_matt

My Feedback: (10)

Agreed 100%

BTW I have definitely had RX installs that could almost be considered "insulated"!

Having said that, my gut feel is that the thing pushing this Futaba temperature issue "over the edge" are installs under a clear canopy. We (at my real job) make products for use in automobiles, and this "dashboard" requirement is beyond difficult (melting high temp ABS at 85C). Rumor has it that Daimler/Chrysler has observed conditions on the dashboard (at Arizona proving grounds) that will boil water.

I cannot imaging the pressure that has been on Futaba and Airtronics engineering to play "catch up" with Spektrum. And look at Hitec. Not a word out of them, and this could kill them long term. Tough business.

rhklenke

My Feedback: (24)

Matt,

I think that the excellent data that Paul has gathered (thanks Paul!) shows that the heat issue with the FASST stuff is fairly minor. I believe that mounting the RX in such a way that it is not in direct sunlight and that it has at least some airflow around it will be more than sufficient. I do not believe that the actual power dissipation rate of the FASST RX's is such that the overall thermal resistance has to be very low to prevent self-heating - i.e., just a little airflow/space should be sufficient.

As far as the pressure on Futaba to "catch up" to Spektrum, I think that's all done with. The FASST system and the high-end Futaba TX's are *vastly* superior to what JR has available. I have heard that the programming on the 12X is similar to that of the 10X, and I can't imaging a worse programming paradigm for a modern radio. I just setup an A-7 EDF on my 12FG and it was a breeze! Remember how much of a pain in the butt it was to mix nose wheel steering to rudder on an aux channel and have a knob for separate nose wheel trim - on either the old Futaba radios or the 10X? On the 12FG, just plug the nose wheel servo into channel 7, set channel 7 to function "Rudder2," activated by "J4" just like the rudder, and trim to "T6," and you are done. Perfectly simple and elegant and no P-mixes involved!

BTW, I just got back from the Joe Nall. We flew FASST RX's in 3 different seaplanes down on the pond. At times there were 6 planes in the air on the pond, 6 in the air on the main flight line, and 6 in the air on the 3D flight line. FASST was rock-solid at all times as far out as we wanted to fly. On Thursday there were a reported 12 transmitters in the impound (for 400+ registered pilots at that time) on the main flight line, so it was obvious there was a lot of 2.4 activity.

I can report that all 3 6-channel RX's were enclosed in air-proof boxes (not necessarily water-proof [] ) and at least they never got hot during operation. In addition, I found out that just like the 72 MHz RX's, the FASST RX's stop working when dunked in the water [&:], but just like the 72 MHz RX's, when you dry them out, they return to function just fine...

This FASST stuff is the best thing to come along to RC since the Jetcat turbine!

Bob

tahustvedt

For what it's worth, the manual of my TM-8 module/608 receiver states that the receiver must be protected from temperature extremes. I bet the 6014 manual says the same.

cactusflyer

My Feedback: (4)

All very good information indeed. It's a shame to see global warming effect our hobby. I'll take a 18° F safety margin any day...That's getting REALLY hot! 176°F!!!! Even for the desert.[:-]


With a little luck, I'm sure this will all work out over time...it usually does.

Tailwinds,

John

Greg G

My Feedback: (5)

I was just curious if these were permanent failures where the RX was damaged or did they just stop working at high temperatures and worked properly again at lower temperature?? I would think it would be hard to get to those temperatures while flying, were there any failures in the air or just on the ground?

Greg

f106jax

My Feedback: (16)

Greg,

The reports indicated that the rx began working normally upon cool down. As I recall, all failures occurred on the ground.

Greg G

My Feedback: (5)

Hi Mike,

Just guessing and its hard to generalise, but Jets may be less affected by the issue perhaps because they have smaller canopies with less clear area, may be more likely to have a cockpit in a clear canopy shading the receiver, and are more likely to have a removeable hatch that can ventilate the radio compartment before flight.??? Jets usually have nose gear retracts that have openings in the fuse usually near the radio compartment that can offer some ventilation...


Seems like common sense, but I guess if you really want to fly in suspect high temperature conditions you should keep yourself and the plane in the shade before flying and ventilate the radio compartment before flight if possible. The TX may have similar issues with its electronics so you should keep that in the shade and not on the dashboard of your car because you would probably be uncomfortable holding a 160 degree TX

Gary Jefferson

My Feedback: (167)

Bob, I wouldn't believe everything you hear!! Not sure if you have read the manual for the new 12X yet, but I have and I can tell you that it is little or nothing like the 10x series of radios. I have owned every JR 10 series of radios (10, 10s, 10sx, 10sxII, and lastly the 10x) since the very first one was introduced and the new 12X is much more like the JR 9303 that I now own in both programming style and flexibility. It is without a doubt a modern radio with great flexibility for what we do with the jets and it likely has more capability than most people will even use or bother to learn anyway.

Heresay from others or having someone on RCU describe what it does, and actually reading the manual are vastly different. Take the time to read the manual and you will see that it is nothing like the 10X (if you are familiar with the 10X) which I agree has been outdated for some time now. Using 10X style programming for a new JR radio would have been a major step backward for JR...Gary

RonLongAZ

My Feedback: (29)

Mike,

I have both JR and Futaba 2.4 systems and I fly in AZ I have not had a problem yet. All Jets Maybee I sould Knock on some wood.


Ronald R Long

rhklenke

My Feedback: (24)

Gary,

I'm glad to hear that they are not sticking with the 10X programming style for the 12X. Yes, I've done a fair bit of 10X programming and its always struck me as completely obtuse and inefficient - requiring PMixes to do almost anything with the aux channels on other than the default switches...

BTW, I like JR stuff too - their servos (8411, 8611, 8711) are by far the best bang for the buck, and I've used their matchboxes and channels expanders too, its just that for "bank-for-buck" wise, the Futaba TX/RX is far better and since I rep. no one, I go where the efficiency is...

Bob