Launching in winter?

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not much effect, if any...Plastic parachutes won't open, but since there is no warm air to rush in, there is very rarely any wind.


https://rocketryforum.com/showthread.php?t=19555




Braden

I really,really dont want to hear about winter :kill: Anywhoo-other than that ,WELCOME :roll:

The cold shouldn't effect black powder motors too much. I think one of the potential problems is cycling the motors between hot and cold repeatedly. This can crack the black powder in the motor and cause it to fail. I have heard of people keeping the motors in their pockets to keep them warm until shortly before launch. That might be overkill, but then again I don't see how it could hurt.

Your rockets will probably be more frragile in extreme cold and you might see more broken fins on landings and things like that.

If you use electronics such as altimeters, the batteries need to be strong to ensure that the electronics work properly. I have had an altimeter fail due to low battery power during a winter launch. The altimeter reported the battery was OK, but something went wrong duroing the flight.

Your rockets probably won't fly as high in very cold air as cold air is denser than hot air and will cause more aerodynamic drag. I am not sure how much difference this will make.

I've flown a couple times on frozen Lake Wissota. It's great, especially if you have a snowmobile for recovery. I usually don't have a problem with chutes not opening if I pack them right before launch. I've never had a problem with cold engines either. Even if the chute doesn't open, snow makes for a nice, soft landing. On the lake it isn't all that deep either, the wind blows a lot of it off.

One little story I have about winter launches. Back in my younger days we'd launch at the local high school. In the winter we had to launch in the parking lot, and they would drift into the football field. I launched an Estes Bandit and the nose cone failed to come off, and it was coming straight down over almost all plowed asphalt. By a big stroke of luck, it landed nose first in the big pile of snow between the road to the parking lot and the sidewalk for the school. It was buried to the fins, but undamaged.

Usually not a problem. It's often harder on the rocket flier than it is on the rocket.

https://www.crmrc.org/gallery2.htm

https://www.crmrc.org/2009_launch_reports.htm#January

https://www.crmrc.org/2010_launch_reports.htm#February

https://www.crmrc.org/2011_launch_reports.htm#January

My old club (The Goddard Society) used to host a sport launch on frozen lakes all the time (The Kelvin Event). The biggest problem was for the folks flying trying to keep warm

Just be sure to follow proper ice safety. Check with the local authorities as to how safe a particular lake is at the time, dress warm, bring a large stick with a nail or spike in the end (to help pull yourself out of the water should you fall through)...

As for winter flying in general, heck CMASS hosts the Winter Follies every January. Here is our most recent.

I also teach rocketry year round in New Hampshire, as can be seen here.

We fly year round also, doesn't get cold enough long enough around here to allow flying from frozen ponds or lakes...just too thin ice but we do fly from frozen snow & ice covered fields during the winter months... Some of us aging members don't do as well as long as we used to LOL!! but the models usually do pretty well. Plastic and Mylar chutes need to be well seasoned (crumpled many many times) and talc baby powdered well to open in sub freezeing weather.

As for BP motors: MOST Catos are seen in low air temp conditions. Remember the 75°f rule. "Launch BP motors within 75°f of the highest ambient temperature to which they have been exposed". The lower the ambient air temp the more likely this can be exceeded.

pick1e said:

I was thinking of good places to launch today (currently launching at the high school field). I'm in Michigan surrounded by farmland so usually if there aren't crops in the fields it's muddy.

Then I thought what about the middle of a frozen lake in the winter? Out on Saginaw Bay (Lake Huron) you can see for miles in any direction. Does the cold affect the motors? What about the rocket's flight in cold air? The only thing I can think of is the materials like fins and glues will be more brittle when frozen.

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A-D motors seem to do well in winter but I have seen E motors cato a lot when it gets around 45* or lower.

Verna
www.vernarockets.com

Verna said:

A-D motors seem to do well in winter but I have seen E motors cato a lot when it gets around 45* or lower.

Verna
www.vernarockets.com

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All BP motors need to be protected from thermal cycling, as Micromeister described. They have a much greater chance of failing when they have been allowed to get too cold for any extended period of time. 45° is a spring day; they can easily survive temps in that range. It becomes a problem with prolonged exposure to temps that are significantly below freezing, especially sub-zero temps. Composite propellent motors don't suffer from this problem. To protect against thermal cycling, store black powder motors in a sheltered, warm location during the cold winter months. At a winter launch, keep them in an inside coat pocket until you are ready to use them.

FWIW, I've seen 3 different people destroy 3 very nice rockets within 15 minutes of each other using E motors, at or just below 45* that had only been on the pads for about 5 minutes before launch. They came out of warm cars. The first I thought was a bad motor. The second a coincidence. The thrid made it obvious to me E's are sensitive to even minor cool temperatures.

On the same day I flew many A-D, including several clusters that had been out all day and after temps had fallen to about freezing with no problems. But I will say that of all the bp motors I have seen cato they have all been E's. Perhaps the larger the motor the more susceptible they are to temps.

Verna
www.vernarockets.com

Verna said:

FWIW, I've seen 3 different people destroy 3 very nice rockets within 15 minutes of each other using E motors, at or just below 45* that had only been on the pads for about 5 minutes before launch. They came out of warm cars. The first I thought was a bad motor. The second a coincidence. The thrid made it obvious to me E's are sensitive to even minor cool temperatures.

On the same day I flew many A-D, including several clusters that had been out all day and after temps had fallen to about freezing with no problems. But I will say that of all the bp motors I have seen cato they have all been E's. Perhaps the larger the motor the more susceptible they are to temps.

Verna
www.vernarockets.com

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I wouldn't blame this entirely on cold. Earlier this year, our club prez had a new pack of E's, all of which exploded imediately on ignition, under good weather conditions. I surely wouldn't think a temp around 45 degrees could be a factor. We fly at temps near zero up here and don't see too much increase in motor failure rate.

I have launched Estes for 40 years and launch E9's like Amy Winehouse goes through cigerettes and I have never, ever seen an Estes engine CATO. Maybe they just ship the good stuff to Texas. oint:

Rocket_Man said:

I have launched Estes for 40 years and launch E9's like Amy Winehouse goes through cigerettes and I have never, ever seen an Estes engine CATO. Maybe they just ship the good stuff to Texas. oint:

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The only times I've ever seen Estes motors CATO it has been E9's, and they've all been fairly recent. I think there's more to the story than temperature.

chadrog said:

The only times I've ever seen Estes motors CATO it has been E9's, and they've all been fairly recent. I think there's more to the story than temperature.

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temperature cycling and humidity. the BP will expand when it gets hydrated, and it will expand when heated. the cycling will cause it to develop microfractures that when exposed to the flame front and pressure will crack and increase the pressure until the clay nozzle explodes.

edwinshap1 said:

temperature cycling and humidity. the BP will expand when it gets hydrated, and it will expand when heated. the cycling will cause it to develop microfractures that when exposed to the flame front and pressure will crack and increase the pressure until the clay nozzle explodes.

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How big of a factor could humidity be on a sealed package?

those packages have printed cardboard backsides, that might prevent a rapid swing in humidity, but they will allow 'moisture' to enter(and leave) slowly. unless the motors are stored in a climate controlled space from manufature to your hands...they will be subject to humidity/temprature cycling. thats not even considering the possibility that they might have been dropped...say when the clerk picks them up, scans them then tosses them on the counter(seen that one, asked the clerk to not do that again).
rex

Rex R said:

those packages have printed cardboard backsides, that might prevent a rapid swing in humidity, but they will allow 'moisture' to enter(and leave) slowly. unless the motors are stored in a climate controlled space from manufature to your hands...they will be subject to humidity/temprature cycling. thats not even considering the possibility that they might have been dropped...say when the clerk picks them up, scans them then tosses them on the counter(seen that one, asked the clerk to not do that again).
rex

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And they have gloss printed front sides. Not much water is going to pass through that, not without a pressure washer that is.

I have to go with the "breathable" cardboard idea. I have packages of A engines from 1972 with rusty igniters but the packages have never been opened.

Verna
www.vernarockets.com

Verna said:

I have to go with the "breathable" cardboard idea. I have packages of A engines from 1972 with rusty igniters but the packages have never been opened.

Verna
www.vernarockets.com

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After nearly 40 years I wouldn't rule anything out!

Geez...45° is anything but cold; it's just moderately cool. It's light jacket or sweatshirt, no gloves weather. It's shorts and a hoodie weather. If motors were having problems at those launches, they weren't caused by the ambient temperature at the time. They may indeed have experienced temperature cycling, but it probably occurred long before they were ever brought out to the launch. Five minutes sitting inside a motor tube inside a rocket at the pad when the air temp is 45° is simply not going to cause the problems associated with temperature cycling. Five minutes sitting at the pad in 20° weather won't even do it. Try a few hours to a few days at temps below 30°.

If motors blow up after spending just a few minutes outdoors at 45°, how the heck do people get away with doing night launches? How the heck do I get away with using E9s at my club's launches in the spring and fall? I have never had a cato with an E9.

Planning on spending half the day standing out on a frozen lake in -6℉ in mid-January? OK, then you'll need to take some precautions.