A little aviation Trivia for ya

[N49185]

The normal mixture for a piston engine is:

A 15 ounces of air for each ounce of fuel
B 30 pounds of air for each pound of fuel
C 15 quarts of air for each quart of fuel
D 30 pints of air for each pint of fuel

Anyone know?

 

[Timebuilder]

14.7 pounds of air for each pound of fuel.

 

[avbug]

15:1 is typical stochiometric, but not the "normal" mixture setting. Mixture is typically richer, on the order of 13-14:1.

 

[Timebuilder]

Funny.

I was thinking that stochiometric would be "normal," and that the richer setting would be "operational."

I guess the semantics left it kind of vague...

 

[Wankel7]

I always that stoichiometric was 14.7 : 1.


I would say your question is not a good question.

There are variables. What condition are you running the engine? Full rich, are you leaning before peak egt, or after peak egt......

Geez, the next time I fly I will just slap my wideband o2 sensor in the stack But my car would miss it

 

[Timebuilder]

In fact, the question did not address airplanes.

Just "piston" engines.

 

[Wankel7]

^^^ Well gee in that case.

It is still a poor question.

But in my car when is in closed loop it is maintaining 14:7 very well. However, when I get on it and goes to open loop it starts to drop to 13:1. This is under mild accel.

However, when I floor it I have tuned it to run about 12.5 : 1.

Before I had it tuned it was off the scale rich. It was just dumping fuel.

Gotta love widebands! So that is how my (Rotary) engine runs. Does that still apply?

Wankel

 

[TonyC]

I think y'all are getting too hung up on the minutia, and failing to see the thrust of the question. There are basically 2 ratios involved, and 2 ways of measuring the fuel and air.

Ratios: 15:1 and 30:1

Measures: Volume and weight



Now, pick the best answer and be done with it !

 

[Timebuilder]

All of the current electronic fuel injection systems I know of (which may not be all of them) use the Bosch licensed designs. At least in this group, which I imagine contains virtually all modern EEM vehicles, 14.7 is a normal value.

The O2 sensor started out as a part of the "lambda" system when Bosch was designing electronic injection to replace CIS systems for Volkswagen. Now, it is a hit in the auto world. OBDII has "dopubled" the sale of sensors, since we now have an upstream AND a downstream sensor. Kinda makes me wish I had bought Bosch stock.

I'm surprised you know about "closed loop." I haven't even said "closed loop" to someone for a least three years!

 

[Timebuilder]

I think y'all are getting too hung up on the minutia, and failing to see the thrust of the question. There are basically 2 ratios involved, and 2 ways of measuring the fuel and air.

Ratios: 15:1 and 30:1

Measures: Volume and weight



Now, pick the best answer and be done with it !

Back in emisssions school, and later on as well, I was taught that volume is a faulty method because it does not take temperature into account, which causes a change in density, whereas a pound of fuel or air is always a pound.

 

[Wankel7]

I'm surprised you know about "closed loop." I haven't even said "closed loop" to someone for a least three years!

I am a car nut I learned all about this when I was tired of using a narrow band o2 sensor to guess my afr. So , I built a wideband kit and learned all about this stuff

Wankel

 

[N49185]

Avbug Wins

Avbug had it right. Question 2. True or False: An American pilot with a U.S. Private pilot certificate and fewer than 200 hours of flying time wants to fly an Aerospatiale Trinidad that is in the United states but registered in France. He may not fly this airplane as PIC.

 

[Typhoon1244]

Jesus! Pull the red knob until it complains then push it back in a little!

(Actually, that's fair advice in a lot of areas, now that I think about it... )

 

[Typhoon1244]

Speaking of trivia...

This is for all you for all you DC-9/MD-80 folks...my dad won a sizable bet with this one: which is further outboard on the ailerons, the control tab, or the trim tab?

 

[enigma]

Speaking of trivia...

This is for all you for all you DC-9/MD-80 folks...my dad won a sizable bet with this one: which is further outboard on the ailerons, the control tab, or the trim tab?

The control tab is inboard. Ref: MD80 maintenance manual.27-10-00, page 5.

enigma

 

[Typhoon1244]

Ref: MD80 maintenance manual.27-10-00, page 5.

You looked it up? Cheater!

 

[TonyC]

Re: Avbug Wins

Avbug had it right.

Not to be disrespectful, but Avbug didn't answer the question. He cited a ratio, but that only eliminates answers B and D (which referred to a 30:1 ratio). He didn't specify volume (which would have been Answer C) or weight (which would have been Answer A).

Now, Timebuilder said "14.7 pounds of air for each pound of fuel" and while it can be argued that he quibbled on the 15, he was very specific about the method of measurement. He later explained why the distinction of measure is important. We can deduce from his explanation why 15 quarts of air for each quart of fuel (Answer C) is incorrect. If I were judging the contest (and I realize I'm not - - and it's not even a contest, after all) I'd give the prize for first correct answer to him.

I need another hobby...