Report on -40F/C test run

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I took advantage of a cold snap here in Fairbanks Alaska to test my new 3P in minus 40F (and C) and thought I would share some of what was observed. After reading at various forums that sudden onset battery failure was a potential problem, I elected to begin a hover test over a homemade 'Pastrana Pit' made of foam padding. I also programmed my C2 button to bring up the battery page to monitor battery temperature. Two new batteries with three flights each were used. Camera was operated in 4K as it produces the most heat, necessitating the tiny muffin fan on the camera module for normal operation.

The bird was initialized inside to try to offset warmup time. Barometer drift became apparent about 1 minute into the hover test, followed by a loss of video transmission about 30 seconds later that never returned. Around a foot of altitude gain per 45 seconds was the norm throughout the test. A 12 foot hover eventually produced a -16 foot reading. Battery temps were at 24C at takeoff and plunged as low as 14C. Taping the battery compartment gills off slowed cooling considerably; all arm vents and VPS vents were left uncovered. Surprisingly, the tiny muffin fan on the camera module seemed to run the entire time.

The bird was lowered to about 6-7 feet and a very significant gimbal oscillation was observed. It looked to be about a 120 cycles per second shake moving the camera about 1/3 inch. The camera recorded flawlessly and the oscillation was not evident when the video was reviewed. No icing was present on the blades or body(extreme cold takes all of the moisture out of the air) and inspection afterwards showed no apparent cracking of the rubber gimbal parts. Up/down camera movement was normal throughout although I purposely kept movement down to a few adjustments every few minutes.

Very surprising was the battery life: from 97% and 96% to 30%(which dropped to 18% in the minute between shutdown and running inside to thaw) both batteries produced 15 and 18 minute flights. The number 1 and 4 cells would drop into the red first, number 1 leading the way. This occurred just at the 30% warning, and 14C battery temp. I elected to land at that point. The batteries have each been charged 7 or so times since then and show no sign of holding a grudge. My P3 was purchased in December and I haven't done any updates but I think I may have the cold weather battery management upgrade on board already.

The clear air of minus 40F is a photographer's dream; if you can compose without video feed you can catch some stunning images. While I am not hoping for more -40F if it shows up I can test my 3P while waiting for pipes to freeze and cars to break down…...
 
And for your nose to fall off LOL! nicely detailed trials. guess I won't complain too much about my 15-20 F temps:cool:
 
I have flown down to zero F area and the phantom handled it better than my fingers...

Nice report and test,
I too noticed gimball shook somewhat at low temps , even an occasional momentary "stick"
but videos were super clear as you mentioned no matter.

Got pretty good at framing shots and video without FPV on an p2 and go pro typ camera so do a lot that way anyhow.

BTW my son and his family are your neighbors,
He is 3-21 Inf at Ft Waiwright.
Yea the temps have been a little chilly. esp for them coming from NC this past summer!

Please let me know if you are posting any videos , I would love to have them check any out.
I sent him a parrot bebop 1 last month I had here so he could get some shots of that awesome scenery.

good luck and have fun flying.
 
I would agree that the hands are the weakest link at these temps. I used Army arctic lanyard mittens(from Ft Wainwright! Got here in '70 as an Army brat) with chem hand warmers inside.

I forgot to mention the RC unit held a charge really well even though it spent most of the test sitting out on a tripod table. I still wonder whether the video tx failure was on the bird or somehow at the RC unit.

Hope to have videos up on YouTube soon. I figured I would have the coldest flight but some character in Alberta flew his at minus 48F and had decent footage up there.

I am looking for the tiniest min/max thermometer I can find to collect that data on my flights. Any ideas?
 
I would agree that the hands are the weakest link at these temps. I used Army arctic lanyard mittens(from Ft Wainwright! Got here in '70 as an Army brat) with chem hand warmers inside.

I forgot to mention the RC unit held a charge really well even though it spent most of the test sitting out on a tripod table. I still wonder whether the video tx failure was on the bird or somehow at the RC unit.

Hope to have videos up on YouTube soon. I figured I would have the coldest flight but some character in Alberta flew his at minus 48F and had decent footage up there.

I am looking for the tiniest min/max thermometer I can find to collect that data on my flights. Any ideas?
If you are a quick learner, (or already a programmer) you could use something like Microchip's MPLAB Xpress evaluation board (part# DM164140). It only reads from -25 to 125C, but you could use something like a LMT88DCKR analog temp sensor, easy to use, paired up with a 16F18855 Microchip microcontroller, the entire package, (plus a 5 volt power supply, perhaps a micro buck converter) need be no larger than a dime!
(Note that you would need a programmer to use the standalone parts)
 
If you are a quick learner, (or already a programmer) you could use something like Microchip's MPLAB Xpress evaluation board (part# DM164140). It only reads from -25 to 125C, but you could use something like a LMT88DCKR analog temp sensor, easy to use, paired up with a 16F18855 Microchip microcontroller, the entire package, (plus a 5 volt power supply, perhaps a micro buck converter) need be no larger than a dime!
(Note that you would need a programmer to use the standalone parts)

Yeah, being a last century analog type of guy that isn't an option but sounds intriguing. I was hoping for something the size(and ease of application) of the old $1 stick on digital LCD clock.
 
Yeah, being a last century analog type of guy that isn't an option but sounds intriguing. I was hoping for something the size(and ease of application) of the old $1 stick on digital LCD clock.

So, how about this? T110 Digital Thermometer Temperature Meter with 2m Probe -50°C to 70°C NEW

I was perusing E-Bay looking for something else, & stumbled upon this, looks kinda like what you were looking for?

(This has 2 meter leads on the probe, way longer than you need, but , it is a NTC (Negative temperature co-efficient) sensor, so, you can cut the leads & re-connect, with no effect on accuracy, you do not even need to keep track of which lead is whitch)
 
That is around the size I am looking for but as I don't want to see the readout in flight I need one that records min/max temps.
 

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