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11-28-2011, 07:06 PM
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Join Date: Jul 2009
Location: Ankeny, IA
Posts: 210
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Winter topic: RVs in ice
In a cursory review of past VAF posts, I see a lot of discussion on how to account for winter operations in our design and construction of pitot/static systems, engine preheaters, etc., but relatively little discussion on what to expect in the most important of winter ops discussions: an actual encounter with in-flight icing.
My first GA encounter with ice was on my first IFR lesson. It was also my first flight in IMC, my first flight as PIC in a nosedragger, and my first flight in a complex aircraft. That was quite a lesson. Later, as a licensed IFR pilot, my next icing encounter was in VMC! If there's one thing I've learned about icing, it's that you can't learn enough about icing.
Disclaimer: Flight in icing conditions is a bad idea. Flight into known icing conditions (unless appropriately equipped) is illegal. If you're contemplating an RV flight that may take you into icing conditions, take the airlines. The risks of flying personal aircraft (RVs et al) into icing conditions are well-documented elsewhere, and if you don't understand those risks, don't fly in air colder than 40 deg F. This posting is not intended to encourage RV operations in icing conditions, nor is it intended to be a place for pilots to pontificate about the dangers of icing.
With all of that out of the way, I'd like to explore the topic of icing and RVs in the same way we would discuss loss of oil pressure, smoke in the cockpit, and dead stick landings: not things you would intentionally subject yourself to, but things that may be more survivable with the right knowledge, preparation, and vigilance.
I'd like to get the insight of the VAF community on how our RVs handle ice, and what we can do to put the odds in our favor after an unintentional encounter with unknown icing conditions. How does the RV airfoil react to ice accumulation? How quickly does visibility diminish relative to performance? What are the first signs of ice accumulation on the airframe? On the instrument panel?
Obviously, mileage varies greatly from one situation to the next, but if we can share some insight here, we may be able to help a fellow RV'er turn a tense situation into an uneventful outcome.
Thanks,
M
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11-28-2011, 08:08 PM
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Join Date: Mar 2009
Location: Rochester NY
Posts: 669
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Quote:
Originally Posted by foka4
How does the RV airfoil react to ice accumulation? How quickly does visibility diminish relative to performance? What are the first signs of ice accumulation on the airframe? On the instrument panel?
M
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First indication will likely be a complete frosting over of the windscreen. The wing didn't seem affected by a slight amount of ice. The thing that concerned me the most is that the horizontal stabilizer, relatively speaking, is very thin could build accumulation to the point a tail stall would be a real possibility (I didn't have the time or the chance to look out the back and try to assess how much ice was there), so if you get some ice, don't use flaps for the landing. Not too much on the panel (at least mine) that can warn you in advance. If you live up north, including pitot heat in the build isn't a bad idea.
Don't get me wrong - I love this airplane, but it wouldn't be my first choice in icing conditions. Be sure to leave yourself a plan B.
YMMV.
Dan
__________________
RV7A (N7101) - Flying 10/2008
CFI- SE/ME/Inst
A&P
KC2ZEL
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11-28-2011, 09:12 PM
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Join Date: Feb 2006
Location: Springdale, WA
Posts: 6
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RV9A in ice
I used my 9A to commute to my job in Seattle across the Cascade Mountains from my home in Eastern Washington for a couple of years. I normally filed IFR and the major concern I had was icing. I never picked up more than a quarter inch or so of rime, but that was enough to knock 300fpm off the climb and fifteen knots off the cruise until the ice sublimated off. The major effect I had was with the composite MT prop. The ice sheds unevenly and the prop vibrates in an unsettling manner. I don't fly IFR anymore unless I can stay out of the clouds when icing is possible. I commuted for several years previous to this in a Cessna 205 that would pretty much slog its way through anything but it was twice as heavy and had 100 more horsepower. RV's are great little airplanes but my advice is don't fly them in ice.
Bob House RV9A 462BD
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11-28-2011, 09:33 PM
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Join Date: Oct 2007
Location: Sacramento, CA
Posts: 3,351
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I have got caught in it twice and rather lightly. The surprising part was that both times were in summer time and I had expected it the least. The first time, it scared the heck out of me and the first sign was the ice on the canopy which seemed like a trail of water then I realized it was ice. Requesting higher got me out of the cloud and short time later, it was all gone.
The second time it was in the mountains over Idaho, I couldn?t go higher due to temp and couldn?t go lower due to MEA. Both times ice formed on the wing root area and wind shield only.
I will do all I can to stay away from ice as it scares the heck out of me.
__________________
Mehrdad
N825SM RV7A - IO360M1B - SOLD
N825MS RV14A - IO390 - Flying
Dues paid
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11-28-2011, 09:36 PM
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Join Date: Oct 2006
Location: Southeast
Posts: 569
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I maintain my normal flying activities throughout the winter, but more closely pick my spots in traveling from Illinois to New York. After all, it's not legal to fly a plane into known icing conditions without the appropriate equipment, i.e. heated windshield, heated or anti-iced prop, leading edge deicing boots, etc. The definition of known icing conditions is somewhat subjective as in "unless someone reports it in the location your flying, it's not known." At least that's how I've interpreted it over the past 40 years.
The best tool I've found for RV wintertime flying is an accurate OAT gauge. With a little more thorough detective work during a weather briefing, I've generally found an altitude or route that would work, IFR of course, that would keep the moisture in a liquid form. I've also found ATC to be very accomodating in responding to requests to exit conditions where the ice is actually accumulating. I've seen 1/4" to 1/2" buildup on the airfoil leading edges and found the plane handled it well. But, I made it a point to fly a 10 to 15 kt. faster approach speed.
I don't know why you wouldn't use flaps in the landing mode, It's just that once they're down, don't retract them inflight, something the American Eagle crew found out the hard way a decade ago south of Chicago
Of course, you need to have an out, but it's doable. The dead of winter usually isn't too bad, because any precip is already frozen and won't likely stick with temps below -5C or 25F.
One curious thing I noticed on the ramp on clear, frosty mornings away from home was that frost was only present on insulated or painted surfaces. My unpainted wings and stab accumulated no frost. The fibreglas parts all had frost along with the prop. The adjacent, fully painted, Cherokee 6 was loaded with frost.
I did make it a point to install a windshield defrost setup during my build which helps, but have yet to add pitot heat. My comfort level is different than others, so find yours and equip the plane to match.
Mike
Last edited by alcladrv : 11-28-2011 at 09:39 PM.
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11-28-2011, 10:56 PM
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Join Date: Sep 2006
Location: Townsend, Montana
Posts: 3,179
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RV on ice.....Getting to be that time of year.

__________________
Retired Dam guy. Life is good.
Brian, N155BKsold but bought back.
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11-29-2011, 04:39 AM
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Join Date: Jan 2005
Posts: 1,010
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Icing Encounter in an RV- If You Have to Ask, Don't
Rather than encourage anyone by suggesting how or how much icing an RV can handle, I'd offer the following to anyone who thinks ice is a possibility on an RV flight:
1. Pitot Heat- Don't leave home without it. Test it during you preflight. Know when to turn it on (before you encounter ice).
2. OAT - Don't leave home without it. Pay attention to it whenever you're near moisture. Have a plan before you need to execute one.
3. Carb Heat - especially on an RV, it's NOT a de-ice device. Repeat this to yourself several times. If you're not sure-LEAVE IT ON.
4. Know that when you pull the carb heat knob, you're going to lose some percentage of power- this will make carrying airframe ice more problematic.
Finally, if you're not sure of the answers to the following, you need to do some more studying before flying anywhere where freezing conditions may exist:
1. What happens to your Airspeed indicator if the pitot inlet ices over?
2. What happens to AS if the pitot drain ices over as well?
Fly safe.
Terry, CFI
RV9A N323TP
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11-29-2011, 07:24 AM
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Join Date: Mar 2009
Location: Rochester NY
Posts: 669
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Quote:
Originally Posted by alcladrv
I don't know why you wouldn't use flaps in the landing mode...
Mike
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Dropping flaps can induce a tail stall
__________________
RV7A (N7101) - Flying 10/2008
CFI- SE/ME/Inst
A&P
KC2ZEL
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11-29-2011, 09:10 AM
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Join Date: Jan 2005
Location: Rockwall, TX
Posts: 103
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Ice forecast tool
I'm now old enough to admit that I hate flying in ice. I avoid it like the plague in anything without a turbine engine (there's no magic to the turbine, but most have the performance and equipment I desire to get out of or through the ice).
Historically ice has been very difficult to forecast (except during freezing rain events, of course). Now there is a great tool on the ADDS weather system that I've found very useful and generally accurate....
http://www.aviationweather.gov/adds/icing/icing_nav.php
It does a great job of pulling together probability, severity, and PIREPs into one graphic. You can play around with the times and altitudes to help yourself avoid unpleasant encounters. Like any forecast, it isn't perfect, but this is the best I've found for icing info.
__________________
Tom Chandler,
AOPA Regional Manager - Central Southwest
RV-4 bought it, sold it, bought it back, storm totaled it 
ATP, CFII
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11-29-2011, 10:22 AM
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Join Date: Nov 2009
Location: somewherville
Posts: 160
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Quote:
Originally Posted by DanBaier
Dropping flaps can induce a tail stall
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If I'm carrying ice, and the airplane is flying, I'm not changing the configuration period.
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