Date: Tue, 13 Jul 1999 22:03:22 -0500 From: David Domeier Subject: COZY: Ice and the Cozy John, re " What happens if the air filter ices up? " The same question occurred to me when I was installing all that stuff, and the answer to myself was it is a fairly large filter area and most of it is not facing the air stream coming into the box. I would think the front of the filter would ice up first and then gradually around the sides and finally the rear area. At that point, obviously, the engine would be an anchor. The reality of such a situation is that the airplane will be covered with ice also, and with or without the engine, it won't fly for long. These machines were not designed to be flown in freezing precip. There is no provision for ice on the airframe or in the engine intake. Carb heat might prevent ice but it won't remove it. So - the bottom line is, DO NOT fly a Cozy in freezing precip. dd PS I once overheard a Cherokee pilot report losing altitude over water on V44 southeast of Long Island. It was a rotten winter day with freezing precip and a ceiling of about 300 feet. ATC vectored the guy toward land and as luck would have it, he broke out and there was a deserted beach right in front of him where he landed. Actually, I thought he went into the sea because we were switched to another frequency while all this was going on. I read about the beach landing in the paper the next morning. He was one lucky hombre. From: "Russ Fisher" Subject: Re: COZY: Ice and the Cozy Date: Wed, 14 Jul 1999 00:08:48 -0400 > re " What happens if the air filter ices up? " Start looking for a place to land - in a hurry. > The same question occurred to me when I was installing all that >stuff, and the answer to myself was it is a fairly large filter area and >most of it is not facing the air stream coming into the box. I would >think the front of the filter would ice up first and then gradually >around the sides and finally the rear area. At that point, obviously, >the engine would be an anchor. As we all leaned in ground school, carb ice occurs when the temperature of the air entering the carb drops suddenly as it's pressure is reduced due to the venturi. This can happen with no visible precip or moisture. The pressure/temperature drop does not occur in the filter box, so this should not normally be a concern. However, if you plan on flying in conditions conducive to ice buildup on the air filter, you really should be flying something other than a Cozy. Russ Fisher Date: Wed, 14 Jul 1999 09:29:10 -0400 From: bil kleb Subject: Re: COZY: Ice and the Cozy Russ Fisher wrote: > > As we all leaned in ground school, carb ice occurs when the temperature > of the air entering the carb drops suddenly as it's pressure is reduced > due to the venturi. ah, yes; but it is largely wrong. the temp drop due to the venturi effect is small compared to the temperature drop due to the fuel changing phase from liquid to vapor. hence the reason that the ellison still requires "carb" heat. if you're webified see http://www.ez.org/carb_ice.htm for a handy chart of probable icing conditions, and ellison's excellent summary at http://www.ellison-fluid-systems.com/faqs/carburetor_heat.htm btw: i am trying to get one of the original carburetor icing reports online... -- bil From: "Russ Fisher" Subject: Re: COZY: Ice and the Cozy Date: Wed, 14 Jul 1999 18:45:36 -0400 Russ Fisher Bil Kleb wrote: >the temp drop due to the venturi >effect is small compared to the temperature drop due to the fuel >changing >phase from liquid to vapor. hence the reason that the ellison still >requires "carb" heat. No argument from me on this, however the temp drop still takes place in the throttle body, NOT the filter box. From: cdenk@ix.netcom.com Date: Fri, 16 Jul 1999 16:46:35 -0500 (CDT) Subject: Re: COZY: Ice and the Cozy More than just that!! Any visible (even fog or mist) and temps near freezing! From: cdenk@ix.netcom.com Date: Wed, 14 Jul 1999 20:31:34 -0500 (CDT) Subject: COZY: Ice on a Cosy Some comments on airframe icing 1: try very hard to stay away from icing conditions 2: Icing can occur at anytime there is visible moisture and the temperature at or below freezing. 3: It might occur with a temperature inversion, that climbing may eliminate icing. 4: Understand that below a certain temperature icing is unlikely, might be around 15 F. Have had 3 experiences with icing: 1: ILS approach tops at 5000, clear above, Awos reporting 1800 broken, 3000 overcast, temp 28F. airport elev. 780. Approach cleared us from 7000' to 3000'. I asked for cruise 3000', intending to stay just above clouds to last moment, then quick down through layer. Wasn't in clouds more than minute. On final added 5 knots to airspeed. Carrier landing, had moderate nose up attitude, but unable to get nose higher for flare. When pushing plane into hanger there was 1/8" thick ice on leading edges. 2: Departing Jackson, Wyoming, at 15,000' IFR was in middle of thin overcast layer for a half hour. Was able to continuously see blue sky up, and the ground below. Picked up light rime (looked like frost) on leading edges. With plenty of warm air below, decided to see what was going to happen. Cloud disappeared, frost sublimed off, and plane flew the same all the time. 3: IFR from Asheville, NC to Cleveland, Ohio. TOps forcast and were 5000' overcast, scattered snow showers all the way. Conditions to improve at destination at arrival time. Departing a snow shower was moving in the departure end of the runway. Asked for and got an immediate turn to stay in clear and climbed in clear to VFR on top. Flight to 50 miles from destination clear on top at 8000'. Saw hole in layer and ground below 2 miles off course, turned and went through little hole (still on IFR flight plan) to VFR under overcast. Closer to destination, ceiling got lower, got to minimum vectoring altitude, ceiling scraping canopy, and following edge of a heavy snow shower line on the ground, now away from airport, and 10 miles away the AWOS saying clear and visibility greater than 6 miles. While checking chart, ended in the snow, nose mounted landing lights visible maybe 10 or 20 feet ahead. Was in snow 3 minutes (205 mph). On landing had 1/4" wide x 1/8" thick ice on leading edges. Both approaches ended with 2.5 hours fuel at cruise speed remaining. Barring a mechanical emergency, More than enough to fly to clear conditions. From: Epplin John A Subject: COZY: RE: [c-a] Ice and the Cozy Date: Thu, 15 Jul 1999 08:32:10 -0500 > re " What happens if the air filter ices up? " > > I would like to thank the group for the discussion on this subject. Some really good experience out there. First thing is to avoid known icing conditions, knew that but maybe it takes some words from the wise to make a real believer. I am not sure if I will do anything with the setup I have now. If anything I might drill a series of holes, 1/2 in or larger, around in a circle in the filter cover and make a valve from stainless steel shim stock something like a flower with a screw in the center and bend the petals such that they close the holes until some differential pressure builds up to open them. Simple and very few pounds. Only down side I can see is the possibility of one breaking off and disturbing the airflow. Another related question. Is prop icing sort of cured with the pusher configuration? I never hear any mention of it. Carl D. shared his experiences with us and did not mention prop icing. Just another dumb question Thank again John Epplin Mk4 #467 Date: Thu, 15 Jul 1999 18:07:38 -0700 Subject: COZY: Re: [c-a] Ice and the Cozy From: "Dan & Jill Patch" John Wrote: > > Another related question. Is prop icing sort of cured with the pusher > configuration? I never hear any mention of it. Carl D. shared his > experiences with us and did not mention prop icing. Just another dumb > question. > > Thank again > > John Epplin Mk4 #467 John, Prop icing is pretty much not a problem in pushers. By the time significant prop icing would occur, you have already hit the ground out of control from an iced-up canard. Seriously, I haven't heard of prop icing in any of the canards, but I think that is because that very, very few canard operators are foolish enough fly in conditions that would lend themselves to severe prop OR airframe icing. A friend of mine was killed many years ago in a VariEze in what probably was an icing situation (known freezing rain at the surface, tops @ 12,000 ft). No info. on prop icing in this case, but the airframe disintegrated from EXTREME overspeed (>300 kts.?) suggesting nearly complete loss of canard lift (or 50 other possibilities???). If the prop is properly "clocked" (i.e., a soot free setting) exhaust gases will not impinge on the prop so you couldn't expect any help there. Anyone who has flown in rain can attest to the fact that plenty of rain can and does hit the prop. In summary, it would take a mighty strong argument to convince me that pushers are significantly more or less susceptible to icing than the "wrong end brand" under similar conditions. I sure wouldn't bet my life on it! Regards, Dan VariEze N862DP Date: Thu, 15 Jul 1999 22:28:45 -0500 From: Michael Amick Subject: Re: COZY: Re: [c-a] Ice and the Cozy > John Wrote: > > > > Another related question. Is prop icing sort of cured with the pusher > > configuration? I never hear any mention of it. Carl D. shared his > > experiences with us and did not mention prop icing. Just another dumb > > question. > > I've had light airframe & prop ice in Cessna 182 172 & 152 ; most all on let down. Icing on most props occurs pretty close to the hub. Note that "Hot Props" electric pads are about 1/3 the blade length or less. Centrifical force removes the stuff farther out. In these airplanes 1/3 of the blade rides in the heat bath of air exiting the cowling. Just my 2cents though, as I'm still building. Michael Amick From: cdenk@ix.netcom.com Date: Fri, 16 Jul 1999 15:44:10 -0500 (CDT) Subject: Re: COZY: Re: [c-a] Ice and the Cozy Didn't notice any icing, but also didn't look specifically for it. Was concerned about icing of the airfilter which is directly in the airstream. From: cdenk@ix.netcom.com Date: Fri, 16 Jul 1999 16:31:53 -0500 (CDT) Subject: Re: COZY: RE: [c-a] Ice and the Cozy The engine dies! unless you have a proper alternate air source, then with the alternate air turned on, you continue flying, possibly at slightly reduced power, abiet carb heat drop. Carb heat is a form of alternate air. Serves dual purpose on carburated engines to eliminate carb venturi icing. Just to be sure everone understands, there are atleast 5 type of icing discussed recently: 1: Airframe - destroyed airfoil on lifting surfaces and weight 2: Propeller - destroyed trust and possible balance issues when one blade has more ice than the other. 3: Airfilter - Starve the engine of oxygen 4: Carb Ice - internal carbureter- lack of oxygen for engine 5: Control Ice - Ice locks up and prevents movement of control surface - Elevator control tube at fuselage Beach King Air, Piper Aztec, and others properly equipped can handle some ice. The Ez's are poor at handling ice. I have made many NO GO decisions due to low ceilings (1000' or more), clouds only 2000' or less thick, and clear above, with ground temps less than 40 F. The instances I noted recently are total icing experience in almost 6 years and 700+ hours flying. And those 3 instances were after considerable discussions with weather briefer, checking weather in route, and reserving much gasoline. Probably as a result my own standards have been made more conservative.