I own one but have not tried it
Just found the "ICEMAN" carburetor ice detector while reading through a website of a 6A builder in Oswego New York and it really peaked my attention. Carb ice almost ruined my day once so I really respect it.
Anyone have any experience with one of these? Are they worth it for us Carb Guys? If they work like advertised it might be a good addition to my panel but I thought I better run it through the VAF Skunk Works first.
I have one but never used it yet, sorry. I have a carb temp still. I did research this before.
Apparently the ICE MAN can be a pain in the back side with being too sensitive and faults alarms. This was one PIREP I read on the web years ago. The ICE MAN signals you as soon as the optical sensor gets some frost on it, which is not really a threat (yet). Unfortunately this makes the alarm go off a lot, apparently from what I read. That is great, giving you warning of potential ice condition before you actually start losing RPM or manifold pressure. However if it goes off all the time at min sensitivity, you end up flying around with carb heat all the time or just turn the ICE MAN off. Again I am using my memory of what I read in the past. I think it was a C-182, may be with a Continental. Some Continental's in C-182's are known to be super sensitive to ice (frost). I suspect the RV will not set the ICE MAN off as much because the carb and incoming air tends to be much warmer, due to the compact cowl and exhaust location.
With a Carb Temp gauge is not a DIRECT indication of ice accumulation but you can see the actual temp down stream of the venturi (after where fuel is added), just before the butter-fly. This is the critical area. I think most RV'ers with Carb Air Temp gauges will confirm their air temps tend to run above 0C (32F). If the air is above freezing, there is no carb ice possible. However in cold conditions and lower power the temps can get into the danger zone.
Most carb temp gauges have the yellow band from about 0C to -10C (some times +5C to -15C). Below -10C (-15C) its too cold for ice to form, since all mosture is already frozen. Between 0 and -10C you can have super cool liquid that can still freeze. If air temp is above 0C than no ice, unless the collecting surface is colder.
These temps are for CARB TEMP not ambient, so please don't write me and say you can get icing at 30C (86F).[/U] I know you can get ice at 30C ambient. Carb air temp drop can be as much as 30C; that's why its possible to get carb ice at high ambient temps. The air temp drop occurs past the venturi due to pressure drop and evaporation of fuel.
CARB TEMP GAGUES IS A GOOD TOOL. It says nothing about ice only if the conditions are possible. The ICE MAN actually measures the accumulation of some ICE on the probe. If I put the ICE MAN in I will have to take out the carb temp because there is only one probe location in the Carb. If the ICE MAN behaves itself I will keep it. If not back to carb temp.
I find Carb temps in RV's tend to be out of the yellow, above 0C most of the time because of the ambient conditions I fly and the fact the carb is bolted to a hot sump in a warm lower cowl.
I don't know of any certified plane that requires any carb ice temp or detector.
For the most part GOOD pilot procedures and watching you gauges will keep you safe. However its nice having a Carb Temp gauge.
In potential carb ice conditions I watch the MAP like a hawk. If there is a lot of humidity and temps are below 70F. I will occasionally turn the carb heat on for a minute or two, than turn it off, looking for change in MAP (RPM for fixed prop). Unless the conditions are severe, you really have to only worry about low power for extended periods, not cruise or high power, at least in a RV. However +10C and +80% humidity watch out. Many places in the USA have these conditions at almost any altitude.
Also you probably know RV's and Lycs in general are less prone to Carb ice than say a O470 continental. The Continental induction plenum is cold or colder than a Lycs at least. As I said the Carb tends to cook in the RV. Prolonged LOW POWER, closed butterfly is a real danger, even with a RV or Lyc. I always use partial power on long descents. There is a NTSB report I posted before of an RV'er that had a power loss off field landing due suspected carb ice, after a long idle descent.
I always check for carb ice on the ground during run up if the conditions are prone for carb ice by applying carb heat while watching & listening for the rpm the drop AND THAN increase as (if) the ice melts off. Also when I return to idle after run-up, with carb heat off, I check to see if the RPM is higher than when I started. If it is I might have burned off some ice. I have seen more carb ice on the ground during taxi to the runway than in the air.
SUMMARY OF GOOD TIPS
— Icing forms stealthily.
— Some aircraft/engine combinations are more susceptible than others.
— Icing may occur in warm humid conditions and is a possibility at any time of the year in the UK.
— Mogas makes carb icing more likely.
— Low power settings, such as in a descent or in the circuit, are more prone to give carb icing.
— Use full carb heat frequently when flying in conditions where carb icing is likely. Remember that the RPM gauge is your primary indication for a fixed pitch propeller; manifold pressure for variable pitch.
— Treat the carb heat as an ON/OFF control – either full hot or full cold.
— It takes time for the heat to work and the engine may run roughly while the ice is clearing.
— Timely use of appropriate procedures can PREVENT THIS PROBLEM.
In the event of carb heat system failure in flight:
• Keep out of icing conditions.
• Maintain high throttle setting – full throttle if possible.
• Weaken the mixture slightly.
• Land as soon as reasonably possible.
