Cold weather operation

[JohnW]

I am in Nebraska where it actually gets cold, something a lot of you don't see :D. Today we were sitting at about 19 degrees and it's going to get a lot colder. Has anyone run into equipment problems due to cold such as li-po's loosing power (on a receiver) or a high current drain due the mechanics of the helicopter getting cold and stiff? I am aware of the temp related power loss of Ni-MH batteries. Does this power loss apply when the temp is cold but your pulling high amps on a Ni-MH flight pack? My camera also has Ni-MH and has shut down while I am taking pictures due to the cold.

Do any of you have "hard limits" on temp that that you won't fly below?

[MarkWebber]

I'm even wondering if there isn't some way to keep the rx pack warm in flight. Like a mini heating blanket. I've always flown planks in temps colder than I could stand for long. I'm not sure why heli's would be different but am interested in others replys, too.

[rerazor]

How does the Ap2000i work in cold weather? If for instance your flying in a snow covered field will it still be able to read different temps?

[dreslism]

How does the Ap2000i work in cold weather? If for instance your flying in a snow covered field will it still be able to read different temps?

It *should* be fine. I have not flown with mine in snow yet, but it uses the fma sensor. I used to flyl with my co pilot on an ap plane in the winter and it was fine.

The copilot you were supposed to "calibrate" before each flight. It would wag the rudder to tell you how much differential it saw during calibration.
It would wag a rating of 0 -> 10, with 10 being the best differential.

A few times it only wagged a 2, and this was when it was VERY cloudy and the clouds were low, so a very low ceiling, and it was winter and we had one of those wet and warmer winter days, so it could not see much difference between the ground and the sky at that time.

They always said to fly a helicopter that you need to have at least a reading of 3 or more.

I think the FMA worked differently though as you would calibrate it by pointing the nose at the ground and the tail at the sky and taking a reading.

They also always said to calibrate over the coldest thing you would fly over. For instance if you calibrated over a hot asphalt parking lot, then flew inverted over snow, it might think the snow is colder than the parking lot (meaning the snow is the sky) and try and loop you back upright.


A feature of the fma copilot is that if you were inverted and you centered your sticks, it would loop you back to upright, so I think this is why it needed the pointing to the ground and daily calibration.

I believe the ap2000i works in just keeping the differential the same on both sides of the sensors, so it does not care about mistaking ground for sky or vise versa by not calibrating over the right thing like the fma copilot could.

Any how, enough ramblings by me...

[enigma]

I'm even wondering if there isn't some way to keep the rx pack warm in flight. Like a mini heating blanket. I've always flown planks in temps colder than I could stand for long. I'm not sure why heli's would be different but am interested in others replys, too.
How about hand warming packs?

[rerazor]

Is it possible for the the snow covered ground to be the same/close to the the air temp? Or is that a little to far fetched?

[MarkWebber]

I haven't had the opportunity to fly in the snow, either(that's not such a bad thing :wink: ) As soon as it snows, I will definately give it a go.

Probably more of a concern would be condensation on the electronic components on your heli. A short associated with condensation would not be good on any electrical parts.


Is it possible for the the snow covered ground to be the same/close to the the air temp? Or is that a little to far fetched?


I suppose that would be possible, however unlikely. To date, I have tested the function in the worst IR conditions available to me. I have never been dissatisfied with the performance of the AP2000i. Even immediatly following heavy rain at dawn with very low cloud cover and some fog, I did not have to exceed 70% gain to have very solid stabilization.

[ehx]

Living someplace relatively warm in the winter like Nebraska would be nice for flying. I could do it more often.

All batteries used for RC have reduced output as they get colder. In general, the NiCads hold up the best and Lipos the worst. Nimh and lithium ions are in the middle.

There are two types of cold weather flying. One is where the heli (and the receiver pack) have been exposed to the cold for ~ 1 hour or more. The other is when the heli is brought out from someplace warm and is flown within 15 minute or so. In the first case the battery pack is as cold as it can get and is therefore at its weakest. In the second case it's still cooling off and has a bit more power.

You can do your own tests to see how cold your battery pack can get and still function properly. For example, last year I put my heli outside when it was 0F. After 15 minutes I turned it on and moved the servos around while watching a voltage meter reading of the battery under load. It worked OK. Later, after recharging I put it out for 1 hour. Again the servos worked fine, but the battery was much weaker. Too weak for me to trust it. Last winter I did make some flights with the temps around 15F when the heli had been out for 1 hour plus. No problems.

Of course how your fingers handle the cold is a big deal also. 15F when it's sunny and the winds are calm is much easier on the fingers than 15F when it's overcast and windy. If you haven't done much cold weather flying I suggest you test your fingers also.

[JohnW]

Living someplace relatively warm in the winter like Nebraska would be nice for flying. I could do it more often. :lol: You got me, I just read something about a week or two ago about somebody in Cal. saying it was cold :D

The temp here is o.k. by itself but add the wind in and it really stinks. My wife would kill me if we lived anywhere colder. She hates winters here!

I like your suggestion about setting it outside and taking voltage readings. That will be easy / cheap insurance to get some idea of where the batteries stand.

I have worked outside a lot in the winters, my hands don't like the cold! I have tried gloves without flying and the transmitter just does'nt feel right in my hands. I ran across a link to a transmitter mitt http://www.slopeflyer.com/artman/publish/article_13.shtml It looks like a great idea but there were some first hand warnings about inadvertently hitting switches with it, like throttle hold :shock: :shock:. That could ruin the day when unplanned!

[ehx]

Yep, do your own testing. On the ground first and then in the air. I've tested lithium ion, nicad, and nimh receiver packs down to 0F with no adverse effects. They may quit, but when warmed they come back. Lipos supposedly don't like being below 20F or so. I never tried using them as a receiver pack. I use them all the time in a Maxi Joker for power, but I keep them warm until right before flight and once in use they won't freeze.

I've got a mit too, but don't use it often. I guess with planes hitting the wrong switch on the transmitter is no big deal. With a heli it is. About 6 years ago I read an article about a Swedish flyer who made a transmitter box with a plexiglas cover and it was heated with car tail light bulbs (at low voltage). If I was to do a lot of cold weather heli flying I'd go that route.

One other thing. Watch all your electronics to make sure they seem to be functioning correctly. Especially your gyro. Cold weather can affect them. Give your heli at least 5 minutes to adjust to cold temperatures and you will probably be OK with good modern electronics. No guarantees though.

[furyphoto]

Oh I am so used to the cold! I have lived in Whistler, BC for 12 years, and shoot skiing and other winter stuff regularly.

While my swift is not off the ground yet (motor and esc arrived from tppacks yesterday!) I have done a great deal of shooting in the cold. 2 days ago it was -28c, thats about -18 f Really cold!!! :shock:

I would imagine that helis behave like any other electronics in the cold. here are some tips. but ehx is right, do your own testing!

1 - keep your batteries inside, or in your pocket until you need them. the cold will drain the batteries. If they are warm when you start using them they will last longer. If your batteries regularly warm up during operation this will help them to keep their power. (warm is warm no matter how it gets warm)

2-Enigma is right with the hand warmer packs, but try boot toe warmer chemical packs instead, as they usually have a sticky side for sticking to your socks that you can use to stick them to your batteries. I have shot many times with boot warmers stuck to my camera of flash. http://item.express.ebay.com/32-HAND-32-FOOT-WARMERS-64-TOTAL-WARM-UP_W0QQitemZ220054673691QQihZ012QQtrZexpQQcmdZExpr essItem

3-the MOST important thing about using electronics and especially cameras in the cold is condensation. It's not a big deal when you go out into the cold, but when you come back in to the warm house that the moisture will condense all over your electronics (or inside your lens :( which will lead to fungus in the lens eventually :shock: ) It is good practice to leave your camera or other electronics in some sort of case or bag and let it warm up slowly to room temperature. this might mean putting your heli in a duffel bag outside in the cold, and leaving it in the garage for an hour before bringing it inside, and then leaving it in the bag until it gets to room temperature. Letting moisture condense on your electronics is pretty much like giving your heli a shower. It can ruin the electronics, and cause parts to rust. Please warm it up slowly! My camrea usually stays in the bag for 2 or 3 hours after I come in from shooting in the cold. If you are anxious to see the photos, take the memory card out outside, and put it in your pocket to warm up while you pack up the rest of your gear!

4 - One other note, in -28c the grease in my tripod head froze solid, I could hardly move the thing. So there is a temperature where it might not make sense to fly because your bearings will freeze waiting for you to spin up. I don't know how cold is too cold, but if you can't feel your fingers you probably shouldnt be flying anyway! (although the full size twinstar was flying around here the other day in -28)

Just a little advice from the Great White North.

-A

[JohnW]

I use them all the time in a Maxi Joker for power, but I keep them warm until right before flight and once in use they won't freeze.. I want to find out if the NiMH flight packs I am running will be similar, taking them out of a warm environment prior to flight, if the high amp draw will mitigate the effects the cold has on them. I think I will do some hovering near the ground and seeing how long they hold up.

Watch all your electronics to make sure they seem to be functioning correctly. Especially your gyro. Cold weather can affect them. Give your heli at least 5 minutes to adjust to cold temperatures and you will probably be OK with good modern electronics. No guarantees though. Yeah, I was not thinking about the gyro, that could get exciting.... Would the gyro be obvious as you are lifting off or would it be as likely to start acting funny after your up in the air?

As far as condensation I have always been careful with my SLR's but need to keep that in mind with the hilo also.

[ehx]

With gyros there are just a lot of "it depends". Sometimes with an old Voyager E I would purposely not let the heli adapt to the cold so the gyro would start making weird corrections in the air. This was just for fun. Not a problem if you are expecting it. That was with an old JR400 gyro in normal mode. My guess is the newer, better gyros handle temperature change better. I've never had the urge to find out with my Maxi Joker though.

A Rotopod (or similar) is always helpful in stress testing your heli. It won't protect you from all failures, but hovering very near the ground a gyro failure, for example, probably won't crash your heli.