Recirculate cockpit air to keep feet warm?

I have been watching........yes, a ton of cheap switching convertors create errors to other electronics. This alone can create issues.
Period.
Sunlight/ER keeps feet warm.
Insulation to metal pedals keeps feet warm.
A "warm circulator" may help, insulation is first. Wicking away moisture is second, anything else is a bonus.
No, I have no real time in extreme flying cold, I have dealt with hiking, camping, etc.

Damp sucks.
Solar helps.

Yes, may be warm at the airport, sucks to be way up in cloud shadows.........

On Saturday, December 29, 2018 at 10:55:23 AM UTC-5, Dan Marotta wrote:
A cheap voltage converter is likely to be very noisy in the RF
spectrum.Â* I tried one for charging a pda and it continually broke
squelch on my radio.

And, as to the original topic of circulating cockpit air, I don't think
that would be of much use and the air in the cockpit is cold. You feel
warm due to infrared heating from the sun.Â* I've felt quite warm in the
sunlight, seen my breath condense in front of me, and been very cold the
instant I flew under a lennie.

Dan

Many of us use such a 12V-5V converter to power a device, such as a PDA, phone, tablet or e-reader, that serves as a glide computer. Some of those off-the-shelf voltage converters are radio-noisier than others. I chose one that had a reputation for reasonable quietness, and added ferrite rings on the wires on both ends of it. It does not cause any practical problems with my radio reception.

Interesting musings infrared heating by the sun. Yeah the perceived cooling when the sunlight is blocked is very fast.

An alternative to these insoles are heated socks. I bought a pair years ago from a hunting supply catalog. The advantage is that they warm your feet all around up to your ankles rather than grilling just the bottom of your feet. They run on 4.5VDC. I built a 12V-to-4.5V converter using a fast switching power supply with a simple on-off rocker switch for temperature control. Worked well and did not drain the battery too badly.

Uli
'AS'

Uli: if those socks are designed to work with 3 alkaline cells, nominally 4.5V, they probably would be quite happy with 5V too (like fresh alkalines). (Or you can put a regular silicon diode into the supply line to reduce the 5V to about 4.3.) So you can use a cheap 12V to 5V converter (designed for USB jack charging).


Hi Moshe,

... if those socks are designed to work with 3 alkaline cells, nominally 4.5V,...)
That's exactly how they were supposed to be powered. Each sock had a long lead connecting to a small pouch that held three D-cells (remember those? ;-) ). No on-off switch - basically a 'short circuit' through the socks!

USB port? Ha - I built this long before there were USB ports! :-) The fast switching power supply does a good job of regulating the voltage down to 5V and these socks - being a resistive load - seem to be quite happy with that. I have not measured the amps they draw. A 12V-5V cell phone charger may be at it's limit with that type of load.

Uli
'AS'

I wouldn’t argue with the suggestions for foot/boot insulation – that’s all good. I would only add a perspective on treating causes vs. symptoms.

I lead winter outings for the Sierra Club and have read a moderate amount about the issues of keeping warm. A key point is that the reason (cause) for hands/feet/ears/etc. getting cold is that our core (chest & central organs) are getting cool, so our body compensates to protect the core by reducing blood flow to the extremities (symptom). We of course don’t want to be so warm at our core as to sweat, but one response to feet being cold is to add a layer to our core, so as to move up within the range of comfortable core temperatures. In other words, you might not *feel* particularly cold in your core, but still be able to be somewhat warmer without sweating. Something to consider.
- Frank Allen

Skyboots 4g from www.streckenflug.at are excellent.

On Thursday, December 27, 2018 at 12:40:59 AM UTC-5, V1 wrote:
I wouldn’t argue with the suggestions for foot/boot insulation – that’s all good. I would only add a perspective on treating causes vs. symptoms.

... A key point is that the reason (cause) for hands/feet/ears/etc. getting cold is that our core (chest & central organs) are getting cool, so our body compensates to protect the core by reducing blood flow to the extremities (symptom). ...
- Frank Allen

OK, but people do differ. In my case, with rather long and very skinny legs, my feet (and fingers) get cold even when my core is quite warm and even sweaty. Long underpants and/or leggings like flubber mentioned do help. But like I said, there was a huge change in my feet comfort in cold conditions when I changed from a glider with the transparent canopy extending to the feet vs. one with the feet and lower legs in the shade.

On Thursday, December 27, 2018 at 10:52:22 AM UTC-5, wrote:
On Thursday, December 27, 2018 at 12:40:59 AM UTC-5, V1 wrote:
I wouldn’t argue with the suggestions for foot/boot insulation – that’s all good. I would only add a perspective on treating causes vs. symptoms.

... A key point is that the reason (cause) for hands/feet/ears/etc. getting cold is that our core (chest & central organs) are getting cool, so our body compensates to protect the core by reducing blood flow to the extremities (symptom). ...
- Frank Allen

OK, but people do differ. In my case, with rather long and very skinny legs, my feet (and fingers) get cold even when my core is quite warm and even sweaty. Long underpants and/or leggings like flubber mentioned do help. But like I said, there was a huge change in my feet comfort in cold conditions when I changed from a glider with the transparent canopy extending to the feet vs. one with the feet and lower legs in the shade.

If your feet get cold, wear a bigger/better hat. I use a knitted cap with thinsulate. I switch from a normal soaring hat when I get off tow. Also, I switch socks just before takeoff to reduce moisture, and spray my feet with antiperspirant in the morning. Making sure you don't sweat getting the glider ready is also critical.

The sun and you are about the only sources of natural heat at altitude. Outside air circulating around the feet is especially cold. After eliminating that, then it's conceivable that circulating inside air with the right sun angle might help. But the sun isn't always going to be so cooperating.

For more comfort on a less than nice day, you can be adjusting for +70 on the ground and -30 in the cockpit at altitude. Eventually some heat for the toes is good. With electric heaters under your foot pads, it takes less than a watt per toe and you definitely need to be able to control it.

The best socks I've found are these.
https://www.thorlo.com/shop/men-mountaineering-socks

Those, plus boots, and adjustable layers starting with capilene long johns work for me.

I had really good luck sticking with my original footwear. (after a wave camp participant had to hike out after an accident, serious though to functional footwear)

I think put my cycling neoprene overshoes on OVER my footwear, with chemical footwarmers on TOP of my original footwear, but under the neoprene.

Plenty of warmth, without overheating my toes with the heaters on my feet directly.

In the event of a land out.. Peel them off and on your way.

JP

I have used that idea - neoprene cycling boots over ordinary boots + thick socks. The neoprene helps a little but absolutely nothing like as good as Skyboots 3g or 4g over flying boots. Chemical warmers are ok but a bit pot luck. Electric insoles or socks are OK but the batteries are a nuisance - I have various types in my sock drawer.