I posted this picture on Facebook and got about 75 responses everybody loved it!
Awesome! Than I should think of making an even prettier version to sell on ebay
Your construction looks very similar to what i created and i think the velcro will create a gap between the plastic material and the airframe allowing air in. That is why i used elastics to push my coroplast pieces against the airframe. Yes i know the elastics are not as pretty as velcro but the elastics i used stay very securely.
The gap is very small, I turned on a big flashlight and made a photo so you can see the gap, it's more on one side but it's anyway very small. It can also be minimized even more if I'll sew the velcro directly on textile material and not on the foam. I'll make some more test next week.
Yesterday I did my very first flight of my I1 Pro and the temp was about 34F. I had the battery in the copter when I left my apartment and I put it in the hatch back for the 25 minute drive to the launch site. I set everything up and then took the copter out of the car and set it in the inch deep snow. I quickly powered things up, performed the compass cal, then launched reasonably quickly to limit the time the batteries could get cold.
The flight went on without a problem and when I uploaded the log to HealthyDrones it indicated the temp was 57F at power on and then dropped to 55.7F as I was doing the compass cal. As soon as I got her in the air the temp started rising and by the end of the 8 minute flight the temp was 87F or 29C.
So, what this tells me is if you start with a battery that's warm enough and you don't waste a lot of time getting the bird in the air it should be fine as the current flow will warm the battery. I don't know that I'd want to fly with the temps much less that that as my hands got real cold and I'm not sure I'd want to wear gloves and lose the feel.
Brian
34°F (1°C) is not that low, it will be a an even higher difference when you fly at 14°F (-10°C) and also if it's a photography session, I don't fly around that much as when I make videos, and when the copter is just hovering the temperature of the battery won't rise to much. As you can see in this flight the temperature dropped even when I was flying, don;t remember exactly if I was flying very slow or what. This graph was made with a protector made of the same foil that Dxtrty used, in my test that material is better than 2 mm felt but not as efficient as the 5mm Balsa wood or 5mm extruded polystyrene
looks all a bit complicated, i just use (PE or PP) closed cell foil. you'll find them in diff thicknesses; i use 3mm.
Add some double sided tape to stick it o t frame. i keep some spares in case i lose one.
When i go out for a flight i keep my Batt's in a seperate box around 20˚C and add a 33cc softdrink bottle with water at 60˚C (don't let it touch the batt's)
i flew at 5-8˚C outside T˚ and when i landed after 15-18min flight GoP app indicates 30-35˚C .
i made a new box lined with a Gyproc&tiles with seperations for each batt, (also for safety) so if i pre heat it it will keep warm for a while.
i always double check with a little IR T˚gauge during testing.
2 the Battmobile ! let's go !
Good ideea with the softdrink bottle with heated water
I want to have a light solution for my next backpack, as when I'm with the car there's no problem keeping the batteries warm, but when I'm going to the mountains, hicking, I need to have something light, and so far the handwarmers are ok, they are light and they can be activated anytime, the bottle after a time gets cold and cold will be, on the other hand , the handwarmers can be activated after each flight session, when you open up the backpack and cold reaches to the other batteries.