Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

A few of you may know that I'm a leader in 4-H for the small engines project in our club.  Here's some of the questions I'm asking the 12-18 year old this year.  There are 3 girls and 2 boys this year.  Let's see how you guys/gals stack up.

1.     T or F     An engine is a machine that converts a form of energy into mechanical force.

2.     Small engines are generally rated up to _______ HP.  A) 20     B) 25     C) 30     D) neither A, B or C

3.     Approximately ______% of the energy relaesed when fuel is oxidized in a typical small engine is converted into useful work.

4.     T or F     Heat is the resource that provides the capicity to do work.

5.     T or F     A substance can be in solid, liquid or gas state.

6.     Three methods of heat transfer are ______.     A) conduction, convection and locomotion     B) conduction, radiation and locomotion     C) conduction, convection and radiation     D) neither A, B or C

7.     Horsepower is a unit of power equal to _____.     A) 746W     B) 33,000 lb-ft/min     C) neither A or B     D) either A or B

8.     T or F     Both 4 stroke and 2 stroke engines complete 4 distinctive events during each cycle.

9.     T or F     Small engines are either air-cooled or liquid-cooled.

10.     When heat is added to water, it changes to ________.

11.     T or F     Generators and snow throwers commonly use a verticla shaft, horizontal cylinder engine.

12.     The first successful gasoline engine was developed by _______.     A) Thomas Savery     B) Eugene Lebon     C) James Watt     D) Neither A, B or C

13.     T or F     Kinetic energy is energy of motion.

14.     T or F     Small engines are either spark ignited or compression ignition based on how the fuel is ignited.

15.     When heat it added to ice, it changes to ________>

16.     T or F     The size of lawn tractor engines commonly range from 11 to 18 HP.

Let's see how you do and I'll post the answers later this week.

Sherri

na na na naa...

im a master tech and you guys are zip.

i am so gonna burn for that one...he its gettin kinda hot in here  

later chris...aka master tech

I take issue with the false answer.

Even though the rotaion is in half-there are still 4 events that happen (fuel in-compression-power-exhaust) for 2 stroke.

4 stroke=suck-squeeze-pop-poohie    

18 degrees

MissSnowshoveler wrote:

notice that no one ever goes out for Canadian food.

18Degrees wrote:

Even though there are 4 events in both only the 4 stroke utilises 1 stroke for each event.  The 2 stroke utilises 2 events for each stroke.  So there isn't a distinct intake, compression, power, exhaust in the 2 stroke as they are doubled up, intake/compression and power/exhaust.

I just confused myself, so I hope your happy.  I can see the difference in the engines, but to put into words is something else.  maybe Snowshoveler will grace me with a better worded response. 

Sherri

 Miss SS,

 Even a turbo jet engine is  a 4 cycle engine!!!

It does not even have a piston , intake or exhuast valves!!

                                                    Fred                  

congradulations 18Degrees...miss snowshoveler has officially put you in the corner with a pointy hat on your head .

you might know better than to try to reason with a woman,even if you are right. i would have thought you would have learned that from Paula,she dosent take any prisoners.

so while your here ...you a  er want a beer or what,we wont tell the MISS okay.

later chris

Mrs. Sherri---Not many could have described the two stroke and the four stroke cycle.   I think you deserve an A +  on that information.   That two stroke , especially, amazes me. My group at the Vo-tech  school would take one of the better named chain saws and lean it to run  14,000 rpm,s.   Quite a few of them will rev that high.  Then I would divide by 60 to see how many cycles per second.  It came to  233 cycles per second.  Unreal, and a good 2 stroke will just run for years if proper gas and oil mixture is used.  I guess one reason, it changes oil every two strokes.   Take care and may we hear more from you---Your friend--Will

ha ha ha    It is always frustrating when english teahers write math or tech questions=they don't understand math or tech "enuff" to use the proper words!

my $.02 worth                                                                18  degrees

MissSnowshoveler wrote: Just to pick a few nits

Typos

3. released

4. capacity

Nits

5. There is at least one other state of matter, a plasma. Physicists keep inventing others as they play their math games.

11. Most small engine generators are horizontal shafts. Most generators are run by the utility company and I suspect they are mostly vertical shaft, I'm not sure. I'm thinking in terms of "kilograms (pounds) of generator". as "most"

13. Kinetic energy is the energy in an object that is associated with its motion. A battery in a moving car has potential energy stored inside it and kinetic energy due to its being in motion. The potential energy is moving but is not due to the motion. Another way to look as it is to think of a baseball that is dropped from the top of the empire state building. It starts at rest with a lot of potential energy and no kinetic, its way up high. As it falls the potential energy is turned into kinetic, it gets lower and lower but is travelling faster and faster.

14. Small internal combustion engines normally work that way. Small steam  engines and pneumatic tools both work from an external energy supply. I also have a vague recollection of something called a Stirling Engine that used an external heat source but worked by heating and cooling a gas ( not gasoline)..

Nice set of questions, they have generated some good discussion. How did the young adults do?

18Degrees wrote:
I've seen a number of restaurants that specialize in "Canadian" food. Typically they also have Chineese as well.