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fsxlover

Cessna 152 II, When do you turn on the carburetor heat?

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Hey guys, I finally made my first Carenado purchase and I am very excited to be using this aircraft. I am pretty new to FSX and flying. I am using the Angle of Attack Tutorials to learn. Anyway, so when are you suppose to turn on the carburetor heat? does it have to be on during take off and landing? it seems to me when you turn it on your RPM drops.

 

Thanks everyone.

 

oh I have finally made my first video as well using Carenado Cessna 152 II.  

 

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You can encounter carb icing on the ground on a warm summer day so turn on the carb heat after starting the engine for a while and use it in the air if you encounter icing.

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It's really best if you do as much reading as possible on the subject, rote memorization of procedures is not a good way to learn to fly.

 

With that said, I was taught to always use the carb heat when you are outside of the green arc on the RPM gauge. So in effect, for approach and landing.

You'll want to turn it off in the event of a go-around, because, as you've noticed, it robs power. In the real aircraft, during a go-around you would push both the power full forward, and the carb heat full forward (off) in the same motion.

The above oversimplification has its limitations. Depending on conditions, carb icing is possible even with full power.

Jordan

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I was also taught to apply carb heat during periodic checks such as the FREDA that you do on every turn (or approx. 15 mins or when there's nothing else occupying you) and during downwind checks in the circuit.  A FREDA goes something like this:

Fuel: Valve on and contents sufficient for remaining flight

Radio: Tuned to active ATSU with upcoming frequency tuned in standby

Engine: Carb Heat: ON, note RPM drop, Temps & Pressures in the green, Carb heat: OFF, note RPM rise

Direction Indicator and compass aligned, steering planned heading

Altimeter set to correct pressure setting, aircraft at planned altitude

 

As I got faster at FREDAs during training, I tended to leave the Carb Heat OFF until the end so as to give it a little longer to warm up the carb. I've not noticed FSX ever simulating a little rough running and cough when using carb heat, though this will occur if the heat causes melting of icing that has been taking place and consequent water vapour in the mix.

 

Carb heat is normally switched OFF after you vacate a runway since the mechanism opens a flap that could drag in FOD (grass etc). You tend not to do it before vacating so that you can stay focussed on any ATC instruction.

 

Z

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Case in point, I was in a brand new Cessna Cardinal in NZ in the 1980's flying from Auckland Intl. to Christchurch Intl. I think around 4000'. Clear summer's day. The engine suddenly started to run rough. Suspecting icing I applied carb heat for about 10 secs and the engine proceeded to cut completely. I was over difficult terrain well north of Wellington.  I got the engine restarted but it still ran rough. I called up Wanganui (on the coast to the southwest) reporting possible engine trouble and continued direct. In the descent I applied carb heat as I was trained to do (in the RAF and in my flying club) and at about the 2000' feet the engine was running as sweet as could be. I completed the landing without incident witnessed by a fire engines and ambulance in attendance, all lights flashing. I was invited to take an engineer up for a circuit and the verdict was severe engine icing despite warm ambient conditions and we continued our journey the next day. We were informed that the Cardinal (300 hrs on the clock) was prone to icing issues. In this case I think the early application of carb heat at altitude must have dislodged copious amounts of ice which then succeeded in putting the engine out. Bit of a drama in the end, but better safe than sorry. Lessons?  Don't be shy about applying plenty of carburettor heat when you feel it's needed. It won't do any harm (unless full power is needed for some reason).  Also: where possible, know thy aeroplane.  

 

Regards,

 

Gareth, 

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.Hi,

 

Thanks everyone for your help and all the great tips, it makes a lot more sense now. 

 

Great story Gareth.

 

Thanks again

 

S

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Nice video by the way.

I've never seen a C152 door shut as nicely as Carenado make it - you open the window, grab the door and pull hard then lean on it a bit to make sure it has latched fully. More than once I've had to re-close it in the circuit. First time it happened was a bit scary but after a while you chill out.

 

Some trivial observations on your flying if I may:

  • Get into the habit of doing a power check before takeoff. This is normally done on the taxiway just short of your holding point faced into the wind. RPM 1200, brakes: on, look behind, gauges checked, RPM: 1700, Ts&Ps, carb heat check, mag check, rpm to idle, Ts&Ps, RPM: 1200, Controls: free & correct sense, Harnesses & hatches: secure etc
  • Try to track along the runway after takeoff. Obviously a crosswind makes this more fun.
  • FRET check at 300 feet (Flaps, RPM, Engine, Ts&Ps). Trim for climb attitude (i.e. on full power, pitched up to a 70kt IAS climb you should not require any pitch input on the controls)
  • When landing, ensure the main gear lands first!!! Keep bringing the elevator back until the nose wheel lands itself. You should hear the stall warner just before your main wheels touch.

Better still, go visit your local flying school!! :D


Z

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Thanks Z,

Thank you for the flying tips. I am still learning how to taxi properly with my Saitek Cessna rudder pedals. I am trying to coordinate between pushing on the pedals for rudder movement and breaking. I am not sure if it is the same in the real life flying but it is definitely something I need to improve on, to be able to track along the taxi and take off lines. 

I wish I could join a flying school, it is so expensive though. I would love to do that though.:)

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Thanks Z,

Thank you for the flying tips. I am still learning how to taxi properly with my Saitek Cessna rudder pedals. I am trying to coordinate between pushing on the pedals for rudder movement and breaking. I am not sure if it is the same in the real life flying but it is definitely something I need to improve on, to be able to track along the taxi and take off lines. 

I wish I could join a flying school, it is so expensive though. I would love to do that though.:)

 

You're very welcome. As for difficulties in coordination, you should have seen my early performance on taxi. Woeful. I could never brake without lurching in one direction or another. Eventually my instructor made me put my hands in my lap and then it all started to come together. He then started offering free beer if I could roll the nose wheel over every taxiway light and to this day has never had to pay out (to me or any student afaik).

 

Agree that flying training is expensive but it can be a lot less that most people assume with a bit of planning. Go say hello anyway (most are pretty friendly) and see if they'll sell/loan you a checklist. (It will be much more useful than one you'll find on the internet.)

 

Z

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I've been told that you turn on carb heat when going to 2000RPMs or below on approach or cruise.  I'm studying to get my private pilot license (in a 152) so that's what I think should happen. You check it during a run up (check before taxiing onto runway for take off done on the side of a taxiway or designated area). The RPMs should drop not futher than 125 RPMs if it's working properly (check a checklist for the 152 for precise numbers).

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RPM below the green = carb heat in a Cessna in most cases. My 182 has a carb temp gauge so no guessing for me.

 

That's not true for a Piper though. Some designs are more susceptible than others.

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