Ram Rise?

[sixtyniner]

Can someone please explain to me what this term means. RAM Rise. I was asked this during an interview and have not found the answer since I have been back. Thank you.

 

[dispatchguy]

Basically, it means that youre going so fast, that the temp indicator indicates higher than actual.

Example - actual OAT -50C
Speed, say 400 kts
Ram rise 25 C (since youre going so friggin fast, due to friction of the air)
Indicated (sometimes called total) air temp -25C

Look up Total Air Temperature

 

[norskman2]

Ram temperature rise causes the cockpit temperature gauge to indicate that it is warmer outside than is actually the case. This happens at high speeds/altitudes because of the compression heating of the thin, high speed air against the temp probe, plus frictional heating of the probe also.
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[banned username 2]

Ram Rise is due to frictional heating of the air... It is a true temperature rise on certain areas of the aircraft, it isn't simply a change in indication. The areas that are most affected by this rise are the leading edges of everything (wings, engine inlets, probes, etc...)

We typically see around a 28-30°C ram rise (i.e. our TAT (Total Air Temp also known as RAT or Ram Air Temp) is typically around -27°C while the SAT (Static Air Temp) is -57°C... This would be at say 41,000 ft doing Mach 0.84... We activate our anti-ice systems based on TAT, not SAT... So if you are going fast enough, it could be well below freezing outside but due to ram rise your leading edges are warm enough you don't need A/I...

Hope this helps...

 

[100LL... Again!]

Is that ram rise, or are you just glad to see me?

 

[flying4food]

Is that ram rise, or are you just glad to see me?

LOL, LOL,LOL, that was a good one!!!! You very funny man!!!!

 

[mckpickle]

Ram Rise is also used to describe increase in TQ on turbo prop engines. Example. You run the engines up to 85% TQ. Once you are rolling down the runway the engines get more air since the air is "ramming" into the engine. This will cause your TQ to increase. In the ATR we would set aroun 88% TQ and by the time your at 80+ knots the TQ would be up to the target of 92.5%. Since the air is being forced into the engine it is allowing the engine to perform better.