Simviation Forums

this is more geared for Flight Sim flying, but I know that you real world pilots would know more of the answer than anyone else.


In setting up for a flight, and I set the temperature for 95 degrees F (hot and humid South Carolina summer),  how would I go about figuring out what my Temperature Aloft is going to be, to know if I need Pitot Heat or not?  Is there a general altitude that I should turn on Pitot Heat no matter what the temperature is on the ground?

Granted if the Temp on the ground is below 70, I would probably need heat even at 10,000 AGL; but if the temp is 90 - 100 at the surface, do I still need it at 10,000 AGL?



Just trying to get the most realistic settings and experience out of FS9.

I guess there are two parts to your question. First is figuring out temperature aloft. The quick way to do this is to use the standard lapse rate of 2

The second part of your question is about when to use pitot heat. In reciprocating engine aircraft, pitot heat is typically turned on prior to flight into visible moisture. This is usually done even if the temperature is above freezing. If the temperature is around freezing but there is no visible moisture, there is no need for pitot heat. Most jet aircraft will leave the pitot heat on for the entire duration of the flight, regardless of the weather conditions.

Indeed. I don't think there are too many disadvantages to having it on all the time anyway.

The second part of your question is about when to use pitot heat. In reciprocating engine aircraft, pitot heat is typically turned on prior to flight into visible moisture. This is usually done even if the temperature is above freezing. If the temperature is around freezing but there is no visible moisture, there is no need for pitot heat. Most jet aircraft will leave the pitot heat on for the entire duration of the flight, regardless of the weather conditions.

Indeed. I don't think there are too many disadvantages to having it on all the time anyway.

I think the Pitot Tube does consume a fair few Amps from the Power supply, which probably affects smaller GA Aircraft with limited Battery Power.

..and of course, those of us with piston prop, normally aspirated engines, also have to remember to apply our Carburetor Heat at regular intervals, (especially before closing the Throttle), the prevent Carburettor Icing! ....again this puts a strain on the Battery if left on unnecessarily.

Its always a good idea to remember to apply Pitot Heat, and Carburettor Heat at regular intervals during the flight, whilst keeping a careful watch on the instruments, and listen to the sound of the sound of the Engine(s) for possible malfunction...It will help in the "Real Flight"... ...!

Paul

..and of course, those of us with piston prop, normally aspirated engines, also have to remember to apply our Carburetor Heat at regular intervals, (especially before closing the Throttle), the prevent Carburetor Icing! ....again this puts a strain on the Battery if left on unnecessarily.

I think you're getting confused here Paul. Carburettor heating on a normally aspirated piston engine is done with hot air diverted from the engine exhaust manifold. No electric power is involved. This can reduce the available power from the engine so be careful when you use it.

..and of course, those of us with piston prop, normally aspirated engines, also have to remember to apply our Carburetor Heat at regular intervals, (especially before closing the Throttle), the prevent Carburetor Icing! ....again this puts a strain on the Battery if left on unnecessarily.

I think you're getting confused here Paul. Carburettor heating on a normally aspirated piston engine is done with hot air diverted from the engine exhaust manifold. No electric power is involved. This can reduce the available power from the engine so be careful when you use it.

...quite right, Doug....

...Knickers in a twist again... ..!

Carb Heat affects the Power available.

I've got so used to applying Carb Heat on all my little Cessna 150/152's, that its now become automatic to use it when necessary....

Apply heat before closing the Throttle prior to landing, and cancel Carb Heat before touch down if an aborted landing becomes necessary and maximum power is required for go-around, ....or a touch-and-go.. ...!

..the same Icing problem affected all my "Old" Motor Bikes, and Vintage Motor Car, fitted with Carburettors, in adverse Cold + High Humidity Weather conditions.... ....!

Paul...just heating up a nice Cup of Tetley Tea... ...!

When I fly a carburettor equiped airplane, I touch the carb-heat lever any time I touch the throttle, and then decide whether or not to apply it. In most C172s, this is easy, becuase the throttle and carb-heat are next to each other. If you have a large hand, you can grab them simultaneously.

As for pitot heat... I have two, hard rules.

1) Always on while IFR
2) Never on until airborne

A pitot heating element can overheat and burn out while on the ground.

The other good rule to  "live"  by.. is that if you think pitot ice is possible...you should either be flying IFR, or not flying at all  8-)

I think you're getting confused here Paul. Carburettor heating on a normally aspirated piston engine is done with hot air diverted from the engine exhaust manifold. No electric power is involved. This can reduce the available power from the engine so be careful when you use it.

Apply heat before closing the Throttle prior to landing, and cancel Carb Heat before touch down, if an aborted landing becomes necessary and maximum power is required for go-around, ....or a touch-and-go.. ...!

I wouldn't be doing anything else right before touchdown except flying the airplane!

Since we're splitting hairs   :)

I wouldn't be doing anything else right before touchdown except flying the airplane!  The flare and landing should have your full attention.  You shouldn't be fumbling around with the carb heat.  It can be closed after touchdown.  Should a go-around be needed, carb heat in, full power!

I turn it off on short final. A go-around could very well be a last second decision where the difference twixt hitting the runway in the manner you're trying to avoid, and climbing away safely will require instant throttle response.. even a worse time to be groping for the carb-heat knob.

Also Brett.... #2 - Never on until airborne.

Pitot Heat is usually a line-up checklist item.  I always turn it on while taxiing on to the active, along with transponder and lights.  If you have to wait awhile before takeoff, then leave it off.

Can't argue with that technique.. I'll admit that it's a personal rule. Turn on course, turn on pitot heat (if IFR).

[quote]Since we're splitting hairs

[quote]Since we're splitting hairs

carb heat.  = on BEFORE Idle, off BEFORE bat out of hell.  -- gotcha.

pitot heat = (ugh i hate metric scale being i live in Farenheight land) -- (reported ground temp) - 3.5

The nice thing about the little Cessna Trainers, is the "Aircraft Owners Handbook".

A careful study of that covers most everything, and puts you in good stead for managing most Aircraft... ...!

Paul....G-BPLF...FS 2004... 8-)...!

P.S....I wonder how many Simmers actually read it?...

I should point out that quite a lot of light aircraft have no carb heat control or heated pitot head. I'm thinking specifically of the Tiger Moth but there are many others.

A careful study of that covers most everything, and puts you in good stead for managing most Aircraft... ...!

Paul. I've noticed a worrying trend towards Americanisms in your recent posts. First carburetor & now this.

I should point out that quite a lot of light aircraft have no carb heat control or heated pitot head. I'm thinking specifically of the Tiger Moth but there are many others.

A careful study of that covers most everything, and puts you in good stead for managing most Aircraft... ...!

Paul. I've noticed a worrying trend towards Americanisms in your recent posts. First carburetor & now this.

Well, Doug...

I was "almost exactly" right... ... ... ...!

Paul... ... ...!

P.S. ..I must ignore the fact that my Firefox Dictionary keeps telling me that there are NOT two "T"'s in Carburettor... ...!

.... ....!