Isn’t the lightbulb idea simpler and as good as the oil radiator, which will likely use up more electricity thus contribute more towards global warming?
Honestly asking about the downside of a simple lightbulb instead of a more elaborate solution, assuming electricity is available.
A lightbulb has the added benefit of always raising the temperature somewhat above ambient, whereas an electric heater would need the thermostat set to some relatively high temperature. Then again, the bulb might not be enough when it’s really cold…
I use ready silicate bags (€ 8 each) from the car supply shop in my airplane. Started when I had condensation in the PFD – has not happened again. Airplane stands on a turntable … so I cannot leave it with electricity connected.
The lightbulb is very dangerous. It produces temperatures of 2500-3000°C inside and easily over 100°C on the outside. An oil radiator does not have any high temperatures anywhere and dissipates heat over a large surface. It can be configured to dissipate the same energy as a lightbulb which it achieves using pulse width modulation using the oil as a buffer. The efficiency of the oil radiator is higher because the lightbulb converts some of the energy into photons which is a waste as you don’t want your aircraft to be illuminated.
And of course my electrons only come from solar and water so fully eco friendly.
A free EuroGA bag of silica gel to the first person to spot who is taking the p1ss above 
Cobalt wrote:
CaCl2
I think the difference here is that silica gel adsorbs moisture (not absorbs) but the CaCl2 forms a hydrate that uses up eventually the whole crystal of CaCl2. This means the silica gel’s effectiveness will be very much more based on surface area rather than weight (adsorbtion = moisture is held onto only on the outside surface of the silica gel).
I’ve only ever flown aircraft that have lived outside. But some of the above surprises me.
If you have electricity available, presumably that means that you are inside a hangar. Does the condensation problem exist inside a hanger too?
I, perhaps nievely, assumed that being indoors and out of the rain, the probably wouldn’t exit.
dublinpilot wrote:
Does the condensation problem exist inside a hanger too?
Yes, of course unless the hangar is sealed and heated. If you have an air mass with a certain water content and you cool it down, relative humidity increases until water condensates.
Try not heating your apartment in winter and you’ll see water condense on the inner side of the windows, maybe even on the walls.
achimha wrote:
Yes, of course unless the hangar is sealed and heated
Even without that, a draughty unsealed unheated hangar will help.
We tend to get condensation in these parts not on wet overcast days, but from autumn through to spring whenever there is a clear still night. Then everything has condensation on it. Objects outside such as aircraft radiate their heat into outer space, and cool very quickly, well below the air’s dewpoint meaning everything has a thick layer of dew on it (or frost, if it falls below freezing). However, even in an open hangar, so long as the aircraft doesn’t have a view of the sky, no dew will form because the hangar roof prevents the aircraft radiating out into space.
Dew (outside condensation) is a separate topic. Condensation can happen inside the aircraft (e.g. inside instruments) even without any rain or dew involved. It’s just a matter of cooling down air masses with a certain water content.
If you have a nice and warm cabin and you put the aircraft in the hangar, the air will cool down and that alone can give you condensation. I usually get visible moisture inside a a turn coordinator.
Interestingly the most noticeable place in my TB20 is in the two Sandel EHSIs, whose LED → LCD → polariser screen projection system stops working if there is the slightest condensation. The effect disappears a couple of minutes after power-up. I have seen this only a couple of times which is why I am really on the case with the silica gel.
The other approach, already mentioned I think, is to somehow blow dry air into the cockpit. Ideally one would also blow it up the exhaust system. I have found that this can be done with a battery powered device (it needs to power only a small fan, pushing air through a big silica gel bag) but it creates a new problem: if the plane is moved by the ground crew… one would need to somehow attach the device to the plane.
