Problems!! 14MZ 2.4 R6014FS

[rcdart]

Prizzy, the exit guide is actually a 3W product.

[rcflyer]

rcdart, any product link for the 3W exit guide? Thx

[notorious_benny]

http://www.modeldesign.com.au/detail...planeacc&id=10

Heres what they look like.....

I also found them at www.aircraftinternational.com look under accessories and then finishing touches.

[03fomoco]

Ok,
I am in the same boat and was able to fail a 6014 on the bench at 165 degrees, so I shelved them all for now and wanted to see how hot an aircraft really got.

Testing was crude but effective for our use. I used a Fluke meter and also an indoor outdoor thermometer. First we checked the "cheap" thermometer against the Fluke and it was within +/- 2 degrees as we let them stabilize from an air conditioned car to direct sunlight. The aircraft was a Comp ARF 3m Extra with no cans and a sealed unvented fuselage.

The first picture shows the ambient temperature taken half way between the ground and the aircraft. The second shows the temperature taken from the left rear canopy mount bolt hole and the probe under the pilot head "fiberglass" light in color. The third picture is alarming and was a surprise. It was 88 degrees out and under the lexan canopy in direct sunlight the temperature was 156 degrees with an ambient of 88. Wow.

Now for a very interesting flight test right? Ok, FASST on the shelf and two trusty 149dp mounted (this aircraft was not converted to FASST). We took the temperature saturated thermometer and reset the min/max readings and secured it in the aircraft to the wing tube. At the time of canopy install the temp had dropped to 130 degrees. We waited until it read over 150 degrees again and went for engine start. The flight was uneventful.

After flight immediately after shutdown the temp reading was 127 degrees, it was now 91 degrees ambient. We pulled the canopy to check the minimum reading in flight and (ready for this) the temperature was 102.7 in a sealed aircraft, so I guess it is not that well sealed.

Conclusions, an aircraft in the pits in the sun is possibly 52 degrees cooler in the air at 90 degrees ambient. The clear canopy on the Comp ARF is murder for everything inside. An aircraft with minimal ventilation still receives a fair amount of cooling.

Bad news is it was only 92 degrees today and it will be 110 in a month or so. Then what, sadly someone will most likely get hurt before the sky will fall. I think it is irresponsible for a company not to at a minimum state something like "some consumers have experienced heat related failures and product model # jhsdfkl should not be used until further notice for safety." Furthermore they should halt the distribution of the product. Futaba is a large company and needs and wants to protect image but if someone is seriously injured image will mean nothing. I am sure they are working this and none of us are engineers on this product, but the simple fact is this product design does not meet the application requirements that past products did. In a situation like this, if it was known, education and informing the customer would be one of the first priorities.

Dave

[rcflyer]

Are these made of plastics or metal? How are they fastened to the fuse? Thx

[diamondave5]

in case anybody is wondering, its not just the 14, my 617 reciever failed the same way you guys had your 14 fail, it was under the canopy(tinted) of my ef yak, my pcm was in that exact same spot all last year, through the hot summer in tucson, this 2.4 failed 2 weeks ago, not even hot hear yet, put the pcm back in the exact same spot and been flying safely these last 2 weekends, in even hotter temps, and just for the heck of it today i temped my covering with a buddies pyrometer, at 11:00 am the ambient temp was still in the upper 80's, bright sun, the black covering was 169f, so yes stuff gets hot around here, but there is no shade for me, the pavilian has all the work tables under it and no room for a big plane assembled, i checked the canopy and it read 124f, not sure if it was reading the canopy or inside, my buddy said most likley was the canopy surface it self, he was leaving so i didnt get to check it later or check under the canopy, but the point is this stuff is failing at what i consider to not be extreme heat, i want to fly during the summer and i have with my pcm, sweat dripping in my eyes is more of a problem then the pcm ever gave me, i sent my fasst stuff back to tower for a refund, it was less than a month old so i got my money back, i do want to see what happens now and maybe in a year or more i might consider 2.4 again, but it concerns me at this time, you guys in florida heat not having problems?....maybe you need to be west of the mississippi

[03fomoco]

	Quote: Originally Posted by diamondave5
	you guys in florida heat not having problems?....maybe you need to be west of the mississippi

Don't forget they get 2500 more feet of atmosphere to protect them from radiant heat.

[Jurgen Heilig]

	Quote: Originally Posted by rcflyer
	Are these made of plastics or metal? How are they fastened to the fuse? Thx

They are metal and they are not ideal as air scoops. Use some nice NACA air intakes / outlets for electric flight - they work much better.

Jürgen

[rcdart]

	Quote: Originally Posted by rcflyer
	Are these made of plastics or metal? How are they fastened to the fuse? Thx

If you are talking about the exit guides, they are metal and stuck on with thick CA (Loctite 454)

[rcflyer]

	Quote: Originally Posted by Jurgen Heilig
	They are metal and they are not ideal as air scoops. Use some nice NACA air intakes / outlets for electric flight - they work much better. Jürgen

Jurgen, any links? Thx

[diamondave5]

	Quote: Originally Posted by 03fomoco
	Don't forget they get 2500 more feet of atmosphere to protect them from radiant heat.

didnt think about that, i know the sun feels hotter to me here than it did in pennslyvania, even when temps were high in summer there, it cooks me more here, i was around 300-400 feet asl back east

[Flyfalcons]

Diamond Dave, the heat in Florida typically doesn't reach that of the desert. It's just so darn humid that it feels more like 200 degrees.

I'd really like to hear some heat numbers from guys with planes that have fully enclosed fuselages. My Edge is fully enclosed and has no exposure to the sun but I don't have a temp gauge to stick in there. I'm willing to bet without the direct sunlight peeking in that the temps on the ground are much less extreme.

[Jurgen Heilig]

	Quote: Originally Posted by rcflyer
	Jurgen, any links? Thx

Just an example - Graupner stock number 2998:

http://www.cmc-versand.de/Graupner-L....html?ref=1002

Jürgen

[grayuk]

Guys.
We need to get this in context, the sky is NOT falling.
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 (as far as I know).

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 56.7 °C (134.0 °F) Death Valley, California USA 10 July 1913.
(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 today on two models, Hawk and L39.
The Hawk has a canopy floor and the RX is about 3 inches below that.
Picture 1 shows the ambient temp today 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.
Pic 2 shows 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).

So for those of us flying in temperatures up in the 50C/122F area, the first thing to do is remove as much of the radiant heat capture as possible.
Get the rx out of the canopy and under the canopy floor. Consider covering the canopy with a white cloth while standing in the sun.
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 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 today, 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

[reyn3545]

You're missing one key point... a 14 channel receiver should be designed for giant scale airplanes with greenhouse effect canopies! What else can you possibly put that many servos in?