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#1
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Anyone have any bright ideas on how to keep the water from freezing?
Salt? Antifreeze? Anything? |
#2
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On Nov 23, 9:20*pm, Scott Alexander
wrote: Anyone have any bright ideas on how to keep the water from freezing? Salt? Antifreeze? Anything? Yes antifreeze, but the type of antifreeze that is made for winterizing RV drinking water tanks. (not toxic when dumped) -Paul |
#3
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On Nov 23, 10:20*pm, Scott Alexander
wrote: Anyone have any bright ideas on how to keep the water from freezing? Salt? Antifreeze? Anything? The two best solutions are Methanol and Propylene glycol. Salt absolutely not! Cost wise it will depend on how much of a freezing point depression you need. Freezing Point Propylene Glycol Solution (% by mass) F 0 32 10 26 20 18 30 7 Methanol Concentration (% by mass) F 0 32 10 20 20 0 30 -15 Methanol will cost about $3 to $4 per gallon, Propylene Glycol can be purchased as RV antifreeze in either -50 or -100 solutions. These are 25% and 50% solutions so you will need to to dilute accordingly. Price for the -50 runs about $4 a gallon. Lets do a back of the envelope calculation of what you need for a day where you want to protect down to about 15 F. Propylene Glycol you will need a 22% solution by mass or about 27% by volume so you for a 40 gallon total load in your glider you will need about 35 gallons of off the self -50 antifreeze. Cost of about $140 per flight. Methanol you will need about 13% by mass or 16.5% by volume. So you will need about 6.6 gallons of menthanol at a cost of about $25 USD per flight. |
#4
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In the USA methanol (CAS #67561) is a HAP (hazardous air pollutant).
Your state environmental agency will not be happy about your discharge of about 210 lbs of a HAP into the atmosphere. In the concentrations above I suspect the solution would also be classified as flammable by OSHA to say nothing of the risk to your glider and youself in the event of an incident (yes--sparks can happen in a glider accident). Stay away from the methanol. Skip Guimond |
#5
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On Nov 24, 12:20*am, Scott Alexander
wrote: Anyone have any bright ideas on how to keep the water from freezing? Salt? Antifreeze? Anything? You mentioned Dan & Dave Cole in another thread in the context of getting good, conservative advice. Ask them. I predict you'll get some more good, conservative advice :-). Temptation to fly with ballast in extremely cold weather is sometimes an indicator of an excessive BCS ratio. -Evan Ludeman / T8 |
#6
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On Nov 24, 8:39*am, flymaule wrote:
In the USA methanol (CAS #67561) is a HAP (hazardous air pollutant). Your state environmental agency will not be happy about your discharge of about 210 lbs of a HAP into the atmosphere. *In the concentrations above I suspect the solution would also be classified as flammable by OSHA to say nothing of the risk to your glider and youself in the event of an incident (yes--sparks can happen in a glider accident). Stay away from the methanol. Skip Guimond Actually the mixture in these concentrations (under 20%) and temperature ranges (under 10C) will not be flammable and methanol is highly biodegradable. From Wikipedia: "Methanol is readily biodegradable in both aerobic (oxygen present) and anaerobic (oxygen absent) environments. Methanol will not persist in the environment. The "half-life" for methanol in groundwater is just one to seven days, while many common gasoline components have half-lives in the hundreds of days (such as benzene at 10-730 days). Since methanol is miscible with water and biodegradable, methanol is unlikely to accumulate in groundwater, surface water, air or soil. (Reference: Evaluation of the Fate and Transport of Methanol in the Environment, Malcolm Pirnie, January 1999)." No one is recommending that we ingest it or handle the concentrated methanol with bare hands. It is commonly used in windshield washer fluid and other applications. How many gallons of that are sprayed each day? Being a relatively simple organic compound (CH3OH) it breaks down quickly. A better alternative, but I don't know where to buy it would be simple ethanol (95% ETOH and 5% H2O azeotrope) denatured with a few percent methanol. The price should be in the $2 to $3 per gallon range but it is difficult to find currently in mostly pure form do to the concern that you will want to drink it rather than use it for other purposes. Overall you have to have a really good reason to want to carry water in winter conditions to justify the hassle and cost. |
#7
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![]() Stay away from the methanol. Agreed, methanol is bad, you should use Ethanol instead. It is virtually identical to methanol in antifreeze properties, but is non toxic and certainly biodegradable. Plus you can use any leftover ballast as a pre-chilled refreshing post flight celebration beverage. You can also make it yourself for just pennies a gallon. http://www.appropedia.org/Amal's_ethanol_still Just be sure to keep your eyes peeled for those dang revenuers. |
#8
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On Nov 24, 12:26*pm, T8 wrote:
You mentioned Dan & Dave Cole in another thread in the context of getting good, conservative advice. *Ask them. *I predict you'll get some more good, conservative advice :-). Temptation to fly with ballast in extremely cold weather is sometimes an indicator of an excessive BCS ratio. -Evan Ludeman / T8 Ditto on that. We at Blairstown fly ridge all year round, and over the years folks have fiddled with this stuff. There are just too many things to go wrong. I have a great photo somewhere of Dave Michaud (UM) with like 8 lbs of ice (okay, probably not 8) hanging off his tail boom. Some combination of leaking dump valve in the wing and getting the mixing ratio of anti-freeze wrong. Frankly, the days are too short for record flights, so the only reason to carry ballast is to smooth out the ride a bit or go a little faster. I submit that it's just not worth it. P3 |
#9
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On Nov 24, 2:38*pm, Papa3 wrote:
On Nov 24, 12:26*pm, T8 wrote: You mentioned Dan & Dave Cole in another thread in the context of getting good, conservative advice. *Ask them. *I predict you'll get some more good, conservative advice :-). Temptation to fly with ballast in extremely cold weather is sometimes an indicator of an excessive BCS ratio. -Evan Ludeman / T8 Ditto on that. *We at Blairstown fly ridge all year round, and over the years folks have fiddled with this stuff. *There are just too many things to go wrong. * I have a great photo somewhere of Dave Michaud (UM) with like 8 lbs of ice (okay, probably not 8) hanging off his tail boom. * Some combination of leaking dump valve in the wing and getting the mixing ratio of anti-freeze wrong. *Frankly, the days are too short for record flights, so the only reason to carry ballast is to smooth out the ride a bit or go a little faster. * I submit that it's just not worth it. P3 The concern over ballast freezing in the wing is not the issue. Forget about all antifreeze additives, particularly alcohols and salt. As pointed out, leaking valves is the issue. Water cools slowly to zero and then it has to jump 80 calories per gram to freeze (heat of fusion). Starting with relatively warm water gives you many hours of sloshing; I have contest experience in New Zealand with flights of many hours in the wave (-20 degrees) without ballast freezing. The wing's foam cores serve as insulation and freezing is not a problem in all but the most extreme circumstances of time and temperature. Warm water can extend the hours significantly. Carry water all year if you like, just make sure you have water tight valves. Freezing the valves shut is more of a concern than dangling ice for wing-mounted dumps; fuselage dumps are another matter due to possible CG shift from accumulation on the tail boom. Overall, it is not a big concern. ron tabery |
#10
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If there is a concern of water freezing when dumping it out over the
rudder, flaps or ailerons, then consider this. The CRJ-200 has a limitation during certain icing parameters to move the ailerons (wiggle them) every 5,000 feet during climbout. There's been a few CRJ's that had the ailerons freeze up due to ice. Seems like if we were to dump ballast, then during the dumping move the control surfaces back and forth that are going to get wet until the water is all dumped out. |
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