Carb ice

[kaz3g]

I seem to remember the carby heat on a Rotax 912 is more about training than necessity?

 

Kaz

 

 

[SDQDI]

With my 914 I don't have Carby heat

 

 

[Dafydd Llewellyn]

A sensor to measure the temp of the carby body wouldn't be a major cost. It would be a lot colder than ambient. The whole length of the manifold is heated by tapping of some of the exhaust in the car installation with the VW. Nev

Here's another case where people need to read the relevant design standard. DON'T GUESS.

§ 23.1093 Induction system icing protection.

 

(a) Reciprocating engines. Each reciprocating engine air induction system must have means to prevent and eliminate icing. Unless this is done by other means, it must be shown that, in air free of visible moisture at a temperature of 30 °F.—

 

(1) Each airplane with sea level engines using conventional venturi carburetors has a preheater that can provide a heat rise of 90 °F. with the engines at 75 percent of maximum continuous power;

 

(2) Each airplane with altitude engines using conventional venturi carburetors has a preheater that can provide a heat rise of 120 °F. with the engines at 75 percent of maximum continuous power;

 

(3) Each airplane with altitude engines using fuel metering device tending to prevent icing has a preheater that, with the engines at 60 percent of maximum continuous power, can provide a heat rise of—

 

(i) 100 °F.; or

 

(ii) 40 °F., if a fluid deicing system meeting the requirements of §§23.1095 through 23.1099 is installed;

 

(4) Each airplane with sea level engine(s) using fuel metering device tending to prevent icing has a sheltered alternate source of air with a preheat of not less than 60 °F with the engines at 75 percent of maximum continuous power;

 

(5) Each airplane with sea level or altitude engine(s) using fuel injection systems having metering components on which impact ice may accumulate has a preheater capable of providing a heat rise of 75 °F when the engine is operating at 75 percent of its maximum continuous power; and

 

(6) Each airplane with sea level or altitude engine(s) using fuel injection systems not having fuel metering components projecting into the airstream on which ice may form, and introducing fuel into the air induction system downstream of any components or other obstruction on which ice produced by fuel evaporation may form, has a sheltered alternate source of air with a preheat of not less than 60 °F with the engines at 75 percent of its maximum continuous power.

 

(b) Turbine engines. (1) Each turbine engine and its air inlet system must operate throughout the flight power range of the engine (including idling), without the accumulation of ice on engine or inlet system components that would adversely affect engine operation or cause a serious loss of power or thrust—

 

(i) Under the icing conditions specified in appendix C of part 25 of this chapter; and

 

(ii) In snow, both falling and blowing, within the limitations established for the airplane for such operation.

 

(2) Each turbine engine must idle for 30 minutes on the ground, with the air bleed available for engine icing protection at its critical condition, without adverse effect, in an atmosphere that is at a temperature between 15° and 30 °F (between −9° and −1 °C) and has a liquid water content not less than 0.3 grams per cubic meter in the form of drops having a mean effective diameter not less than 20 microns, followed by momentary operation at takeoff power or thrust. During the 30 minutes of idle operation, the engine may be run up periodically to a moderate power or thrust setting in a manner acceptable to the Administrator.

 

© Reciprocating engines with Superchargers. For airplanes with reciprocating engines having superchargers to pressurize the air before it enters the fuel metering device, the heat rise in the air caused by that supercharging at any altitude may be utilized in determining compliance with paragraph (a) of this section if the heat rise utilized is that which will be available, automatically, for the applicable altitudes and operating condition because of supercharging.

 

[Amdt. 23-7, 34 FR 13095, Aug. 13, 1969, as amended by Amdt. 23–15, 39 FR 35460, Oct. 1, 1974; Amdt. 23–17, 41 FR 55465, Dec. 20, 1976; Amdt. 23–18, 42 FR 15041, Mar. 17, 1977; Amdt. 23–29, 49 FR 6847, Feb. 23, 1984; Amdt. 23–43, 58 FR 18973, Apr. 9, 1993; Amdt. 23–51, 61 FR 5137, Feb. 9, 1996]

 

 

[Captain]

Thanks Dafydd,

 

 

 

I found the turbine data particularly useful and can't wait to apply it in my next build.

 

 

 

Bet you are the life of the party at a CASA Men's Night up your way.

 

 

 

However I do need to point out that a couple of my mates were discussing this very issue at the Club the other day and one of them told me that one of your stated amendments has recently been superseded.

 

 

 

Regards Geoff

 

 

[Dafydd Llewellyn]

If that means people are finally starting to look at design standards, and actually think about them, GOOD. FAR 23 applies to everything up to commuter aircraft - read the bit that applies to your situation & ignore the rest.