Moving the GPS and COMPASS MODULE.

[John Hennessy]

Hard to follow all that, but one point I'd like to make is it is not correct to assume six x 25 amp ESCs implies a possible 150 amp load total. The motors are wired in a parallel circuit where all the motors see the same (roughly) line voltage and the total system current is shared by each motor.

Think about it another way, if it really was possible to pull 150 amps (6x25) the battery would last a couple of minutes.

Thanks for that Phaedrus,
I am not that up on electronics, why would Yuneec put in big muti strand cables if they were not needed. That's a lot of cheaper wire that they could use instead of the smaller less trend ones. I will find out from the Yuneec repair shop for Australia that happens to be boutique 3/4 of an hr drive away. The std wire size is 3.3 mm and a huge amount of strands and the adapter is 1.6 mm and 19 strands. When I was young and had a drag car we put the battery in the area behind where the front passenger would sit and needed er cables , so being a Carpenter on a b I found one big cables and used them only to find out when not too successfull by the utopia lectrician that I need one thing like welders cable to be able to carry the amperage over a longer distance.. I will send some photos of see what you think, my mate wants to use the bigger battery and I just thought that it would unsafe.
johnno Hennessy.

 

[John Hennessy]

Thanks for that Phaedrus,
I am not that up on electronics, why would Yuneec put in big muti strand cables if they were not needed. That's a lot of cheaper wire that they could use instead of the smaller less trend ones. I will find out from the Yuneec repair shop for Australia that happens to be boutique 3/4 of an hr drive away. The std wire size is 3.3 mm and a huge amount of strands and the adapter is 1.6 mm and 19 strands. When I was young and had a drag car we put the battery in the area behind where the front passenger would sit and needed er cables , so being a Carpenter on a b I found one big cables and used them only to find out when not too successfull by the utopia lectrician that I need one thing like welders cable to be able to carry the amperage over a longer distance.. I will send some photos of see what you think, my mate wants to use the bigger battery and I just thought that it would unsafe.
johnno Hennessy.

Here are the photos, and your opinion would be great.
Johnno Hennessy.

 

[John Hennessy]

Hi Ronrod68,
I was wondering if your MODULE STAND that you purchased from Ricky Smith was printed like this on the inside or did my mate just the dud. He was expecting it to have at least 4 posts to the module on least like mine. I will put some photos for you to look at and see if his is the same as yours. Thanks for your reply in advance. Johnno Hennessy.

 

[John Hennessy]

Hi Members,
I have recorded some video footage of heat build up in the top of the shell of the H where the compass module is located on a standard she'll and I put the Carbon Fiber STAND on to a shell also and one of my TOWERS on another shell. I had a few spare top shells laying around. The results are amazing and will be posted tomorrow night. Now just a quick test that I could do by myself and not require my mate to be able to get the video ready to load on the forum and a link for the full video, if you watching things get HOT. Don't get me wrong I do but not a machine. Now here are some photos of the temps for my module outside of the H and the inside of the H on its controler.
The ambient temperature was 24.8 °C the module was 24.7 °C and the inside controler was 24.6 °C ,
The module is on 3 extention leads with my white cap just put on top to try and simulate normal flying conditions, (but there was a lot of air getting to it) and also the top shell on the H was loose as you will see. After 10 minutes of being turned on , no motors running, no battery heat from the motors even starting or ideling. The result was module rose to 27.6 °C but the inside controler went to 45.1 °C. These temps were taken with an infrared red thermometer as you will see in the photos.
Now this is what I have been talking about with my TOWER not only does it get the GPS and COMPASS MODULE up and out in clean air but it is out of all that heat. You will see tomorrow night the huge amount of heat that is in and around the ELECTRONICS. So here goes and I hope that this works, but I am slowly getting better.
Johnno Hennessy. Keep flying on the green side of the grass.

 

[RPR]

Can someone post a field flight review? I’m pretty sure that there are a few of you that John sent the module to.

In fairness to John’s hard work, post a flight review.

 

[John Hennessy]

Thanks for that RPR,
Maybe there are a lot like me and are very limited being able to post anything without help, I am hopeless without the help of my mate that guides me every bit of the way. He is fabulous for 72 yrs old and loves it. Now all go to my YouTube channel Yuneek ideaz and you will see the heat video or I will put a link in (hopefully) to a video site.
Now I don't want to bang on about this TOWER of mine and heat inside of the electronics of the H, but it all goes hand in hand if you don't ventilate it gets very hot and I doubt if people realize the temps that it reaches. A brief explanation of how this test was conducted and what was used.
Here is a video of 3 different SHELLS for the test
D) std shell with no compass module (as I don't have enough for all tests) but thermometer sensor in the same compartment with the copper shielding stuck back in place like standard H.
C) std shell, no module, the CARBON FIBER STAND made by Ricky Smith and sold on eBay, hole drilled in the shell where his video said to and the sensor inserted for temps, hole not plugged up and copper shielding with a hole for connector as if on the H.
B) std shell, no module, has Yuneec ideaz TOWER installed and no fan, white in colour with sensor put up inside where the module would sit and copper shielding with the flap cut and sealed as standard.
They are all as standard as can be to the instructions of the makers.
The photographer was me and it is as good as computer knowledge, which is terrible, but stick with it as the results are very significant.
RESULTS-- D) -- std ABS plastic shell 1.5 mm thick heats up quicker and also cools quicker. Characters of the materials and thickness.
C)-- CARBON FIBER STAND takes longer to start to get hot but goes well past all for temps and cools down slower. It is the character of the materials used.
B)-- White Yuneek ideaz TOWER was slowest to heat up and stayed the coolest by 6°C over D and
13 °C over the TOWER that is massive. This is not the fan model, I think that it creates a venturi effect or chimney effect and draws the air through the shell.
Then we go inside or the cooldown and this is where my mate lost most of his hair, I said I thought that the camera was Auto everything, it is but not Auto fix a disaster, but he salvaged some so that you will get the idea. This coupled with the short post and photos the other night gives you some idea of how much heat is generated, and don't forget that we don't have all the electronics running nor motors idling or taking off and flying or battery heat. The test thermometers were purchased from CORE ELECTRONICS Australia and are accurate to .05 of degree C.
After this, my next tests will be the FAN TOWER vs the Std TOWER .
NEXT, a video for Ah-G1 about the flight characteristics that the TOWER may vary on the H. Both my work H'S have both only had there gyros and accelerometers and gimbal s calibrated once and that was when I first purchased them in early 2017. To this day they fly smooth and stable in allconditions, which I will post.

The video s on my YouTube channel Uneek Ideaz. Now I will try to put the video link in.
https://video.com/327207928
If this does not work I will summon some help from my mate, but you can get it on my channel.
Johnno Hennessy,
Keep flying on the green side of the grass.

 

[John Hennessy]

Here is the link for the vimeo video.

 

[Phaedrus]

What happens if you use a black tower?

 

[John Hennessy]

What happens if you use a black tower?

Hi Phaedrus,
With the early testing for temps, the black was the hottest, but that is why I went along designing a fan to go into the Tower.
In the early part of this thread or New TOWER keeping the H cool was the results of the static heat tests. As I move forward I am going to test all of the colours with the FAN TOWER and see what difference there is, which I think there will be but the flow of air from the FAN will substantially reduce this by how much I will have to test and post for all MEMBERS. But colour does have a big influence on the absorption of heat, GOOGLE CLOURS OF AIRCRAFT and there are heaps to read why they are WHITE or SILVER, but we all know that a dark GREY or BLACK H is easier to see than a WHITE one. I have got some easy peel paint (WHITE ) that I will spray one of my top shell's with for a demo and if you don't like it you just peel it off and try another colour. The young car enthusiast's use it to change the colour of there wheels ETC. It is called DUPLI-COLOR CUSTOM WRAP removable coating and all of the youtube vids are American. Have a look and a PLAY. MY COLOURS are on my site uneekideaz.com and some more information on the heat readings. Johnno Hennessy.

 

[John Hennessy]

Here is a shot of the product to paint with. Johnno Hennessy.
Keep flying on the green side of the grass.

 

[Phaedrus]

Years ago I sold cars in Arizona. We did a test with several colors of the same model car to see interior temps in the blazing sun. White was the best, and there was (surprisingly) little difference in other colors. Black and red were the hottest. Other colors almost as hot, and white cooler by a wide margin. I agree on the CF. Bad choice all around.

 

[John Hennessy]

After that information it is nearly the same as my tests. I am sure that I am heading in the right direction and after looking at heat sinks ,which are good but to be super they need air flow,so you need a fan. I decided to loose the weight of E heat sink and concentrate on the fan model.
Johnno Hennessy.

 

[ronrod68]

So after running my H through two batteries (one yuneec and one Ultra-X)

I thought I would go ahead with the battery mod and larger battery offer by R. Smith on Ebay.

So far the gps mod has worked as designed as I had yet to get a gps error message since install

The bird found 17 ants but wood not show as ready and would not allow motor startup.
Powercycled the bird and got the ready indicator and proceeded to take flight. the bird started flying all Wonka and I began getting gps lost warnings.

On the way back toward me it started flying as if it were being controlled by someone else. I was only about two meters in elevation and just prior to running I to a tree I brought down for a hard landing. She flipped and I broke just a prop.
So in summary...don't waste your money on that crap as I did.

You're welcome for the field test. lol
(it was literally over a field)

 

[PatR]

Were those ants found in the wood or on the wood? Sorry, couldn’t resist. Sorry to learn how your experiment ended.

With all due to everyone, Johnno pretty much offered to send me one of his early units but I declined the offer as I stopped doing field tests of experimental stuff a couple years ago. I had also stopped flying my H’s.

Looking back I should have accepted because I knew it would be effective as all the testing Johnno has been doing is nothing more than a repeat of electrical component and systems testing that was performed on both RC and military grade stuff back in 2005, and continued through 2008 with various outfits. Stuff was falling out of the sky like crazy, or failing on the ground before launch after sitting on hot ground for too long. The results of that testing put cooling fans in the avionics of some missile breathing UAV’s and replaced product brands in other stuff. It also changed (increased) the upper limit of minimum thermal resistance requirements.

RC radio manufacturers did not receive the benefits of the test results as they were all maintained “in house” with the various groups conducting the tests. The product buyers paid for what they got and owed manufacturers nothing afterwards. Bear in mind that was all higher end products, not cheap, low quality Chinese stuff. Lacking that info the radio manufactures saw their receivers “cook off” after sitting under a model airplane canopy on warm to hot days. RC Gas engine ignition modules of some brands would do the same thing. End result for either was a crashed airplane. Some VERY expensive airplanes.

Bottom line, electrical components that were not intentionally designed and tested to operate above 60C failed with high frequency. Common components designed with no particular heat resistance often failed above 40C.

So do what you will but if you think EMI is the only destructive activity occurring inside your aircraft and that’s all you address, you will keep losing aircraft. Just look at the manufacturer’s recommended thermal operating range. The window is narrow, limited to fairly benign temps at both ends, and component failure is the reason.

Just for general reference, the better electrical assemblies are certified to -20C/+60C and some ambient environments need more than that on the upper end. Places like Saudi, Arizona, equatorial Africa, and parts of Australia can hit 60C in the shade during the hot months. EMI/RMI testing is a never ending process as frequency combinations, wire gauges, wire/component positions, antennas, and power levels can do things not anticipated using just mathematical theory as a guide.

For the record, I participated in a lot of that testing, so been there, done that. I was also helping Johnno out behind the scenes with design advice on directions to take without providing stats that are still proprietary property. The big guns spent millions of $ establishing exactly what Johnno is learning (verifying actually) in his garage.

 

[PatR]

A couple other things.

For some reason people seem to think you need a rocket scientist to figure this stuff out. Far from it.

Go into a shopping center parking lot on a hot summer day, rest your bare forearms on the trunk of a white car, a red car, and a black car. Which ones burn your arms? One will not, one will be tolerable, one you won’t do a second time.

White reflects heat, black absorbs heat (think solar panels) and red retains heat. Farmers paint their barns red because it retains collected heat longer without gaining too much heat. Black both absorbs and radiates heat, depending on the conditions at the time. Sunny, it collects. Dark and it radiates.

Anything electrical has resistance when current flows through them. An extreme example is a toaster. When not in use it is cold but in use it gets darn hot. It gets hot due to resistance built into the size and type of wire filaments. Similar occurs with our all electric multirotors, and the more current pushed through them the more heat they generate because of resistance. The ESC’s are inside the fuselage and they get HOT! Two of them are right next to the compass/GPS modules.

The basic design of the H chassis and cooling vents virtually prohibits cooling. The inlets are too small and not correctly oriented. Outlet air exit area lacks the area volume necessary to be at all effective. Then we have the placement of the boards that inhibit the free flow of air movement. Worse, there’s no baffling to direct the flow of cooling air to where it’s needed. Hot air rises to the top of the cover, stays there, and collects even more heat just sitting on the ground. Whatcha got is essentially a convection oven.

Lacking a venturi effect there’s nothing present to direct cooling air over, through, and past the boards. Even with a venturi the exit area HAS to be 3x to 4x the inlet area. Then we have air dwell time to deal with. Moving too fast and it won’t collect enough heat to do any good. Adding a tower that provides area volume sufficient to allow hot expanded air to naturally migrate upwards is a great start. Add a low to medium volume fan near the aft portion of the body, in or ahead of the tower, improves cooling efficiency greatly as it draws more air into the cooling inlets and directs it over and through components to the tower. The fan in effect acts like a venturi accelerating air intake volume and flow while the volume of the tower provides the means for hot air with greater expanded volume to escape.

 

[Mrgs1]

There is silver too. The most popular colour here for solar reflective paint, especially for roofs.

 

[RPR]

How come your don’t this module on your H, Pat?

 

[Phaedrus]

I can speak to one example given, that of RC receivers failing due to heat under a canopy on model airplanes. I was involved in some of the testing of the brand that Pat is likely referring to. It was ultimately determined that one batch of of a single model of receivers had an out of spec component installed in it. Shocking as it might be, most consumer RC stuff is not built with Mil-Spec components!! So they are not as robust out of the box.

Subsequent to that batch of failures of a single RX model there have been no issues. And there were no issues with other RX models under similar circumstances. But it shows the importance of mitigating heat and exposure of electronics to it. Even when design specs may allow for operation, there is always the chance for something being out of spec, or a combination of events that result in an out of spec situation.

I placed a piece of white vinyl on the GPS cover on my H+. It is noticeable cooler than the adjacent gray pieces of the cover. I will likely color the entire top shell white using either vinyl or some sort of paint.

I did not pay much attention at the time, but I wonder if DJI got a lot of heat related failures with their Obsidian edition Phantoms compared to the normal white shell. The Phantom shells were not particularly well-vented either.

As to heat testing not being rocket science, here's a story. When I worked in the oil industry we used electronic tools lowered into the well bore to collect information. The deeper you go, the hotter things get. Most logging companies had special "Hot hole" tools. I asked one major supplier how they designed their hot hole tools. The response was "We don't. We take a normal tool, cook it in an oven until something fails. Then we replace that failed component and repeat the process. We keep dong that until it can soak in the oven for 6 hours without failing."

See, not rocket science at all. And this was a billion-dollar company suppling mission critical tools for oilfield use where minutes are worth thousands of dollars and lost time is the Devil. Guess what, even the "tested" hot hole tools still failed fairly frequently. They always brought two along just in case.

 

[PatR]

How come your don’t this module on your H, Pat?

Because I don’t fly them and haven’t flown them since November ‘17. The 920+ was and is better and I enjoy flying it more.

Toss in that I only had one issue with one H in December ‘16 that was corrected, they both always worked perfectly thereafter and I didn’t have a need to fix what wasn’t broken.

I put three flights on the oldest one last year to prepare it for a buyer. I’ve had that one since May 2016 and all it needed was a full calibration and GPS update to be good to go. The buyer didn’t close the deal so it sits with the other on a shelf.

 

[PatR]

Phaedrus,

To expand on your last with a bit of a tangent, experience has shown that most “design” engineers don’t design anything at all. What they really are is “catalog shoppers” and adaptation specialists. They are given a performance requirement and they spend hours, days, or weeks reviewing pre-existing components where the catalog specs fit the bill. From there they spend tons of time adapting them to the task at hand. Once they land on a component they sink their teeth into it like a pit bull and won’t change regardless of being shown how something else could work better. There are very few truly inventive engineers.

If a Chinese company makes something they follow a similar path but take it a step further. Their business model puts cost versus profit ahead of anything else. If pre-existing components can be made cheaper they will be reverse engineered and recreated using lower cost materials and manufacturing processes. That process continues to evolve through multiple iterations until product cost is reduced to the lowest possible level. More often than not some level of component quality is sacrificed to enable lower cost manufacturing. The end result produces components where the original performance specs end up severely corrupted. They even label the stuff with OEM part numbers, allowing them to get mixed in with the original high quality components being sold in other markets. That causes immeasurable problems as the counterfeit stuff frequently fails under various stresses and investigations have to be performed for root cause failure analysis.

Avoiding U.S. military stuff we can look at the RC industry to see where this was done to reduce manufacturing cost and quality in order to undersell the companies that designed and marketed a much better product. DA engines were copied to produce DLE and DLA engines. CH ignitions were copied to make RC Excel ignitions, where one critical component was replaced with a finishing nail to become a conductor. RC Excel continued on that path in copying NGK CM6 spark plugs. Several companies copied and modified 3W engine designs. Have pity for those that bought them. Carden and other high end U.S. and German kit makers saw their stuff copied and restructured to reduce cost, to become Chinese ARF’s. From there the Chinese outfits stole from each other to redesign models to capture their piece of market share, with some brands so structurally defective they would fold up when flown. RC radios have followed the same path, just as multirotor auto pilots have.

None of them functioned as well or as long as the originals but they sold for less money so buyers flocked to the cheapest price and suffered reduced performance and longevity because of it.