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Sep 06, 2010, 02:22 PM
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Stroke vs. cycle


I don't want to be argumentative or anything, and I know in common usage we say "2-cycle" and "4-cycle", but I wanted to mention that there is a difference between a stroke and a cycle.

A stroke is one movement of the piston from top dead center (TDC) to bottom dead center (BDC), or vice versa.

A cycle is one complete process of the engine accomplishing four events: intake, compression, power and exhaust.

What we are describing with "2" or "4" is the number of strokes the piston moves through in order to complete one cycle.

The more correct terms would be "2-stroke cycle" or "4-stroke cycle". In common usage, these are usually shortened to "2-cycle" or "4-cycle", and while it is widely understood what we mean, it is not quite correct.

Again, I do not mean to be argumentative or a smart-aleck at all, but I did want to point out that there is a difference between a stroke and a cycle in engineering terms.
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Sep 06, 2010, 05:19 PM
What goes up must come down
jfacky's Avatar
Quote:
Originally Posted by jbryan80
I don't want to be argumentative or anything, and I know in common usage we say "2-cycle" and "4-cycle", but I wanted to mention that there is a difference between a stroke and a cycle.

A stroke is one movement of the piston from top dead center (TDC) to bottom dead center (BDC), or vice versa.

A cycle is one complete process of the engine accomplishing four events: intake, compression, power and exhaust.

What we are describing with "2" or "4" is the number of strokes the piston moves through in order to complete one cycle.

The more correct terms would be "2-stroke cycle" or "4-stroke cycle". In common usage, these are usually shortened to "2-cycle" or "4-cycle", and while it is widely understood what we mean, it is not quite correct.

Again, I do not mean to be argumentative or a smart-aleck at all, but I did want to point out that there is a difference between a stroke and a cycle in engineering terms.
You are absolutely correct
corrections done
Mar 07, 2012, 12:52 AM
Registered User
ok so it looks like we beat a dead horse to death in this thread how about some useful terminology like:
stab
dihidral
f3d
barn doors

mixing? how do you do that is that when the elevator and ailerons move together to produce quicker pitch

and theres about 50 others i see getting thrown around
Jan 17, 2014, 04:48 PM
Closed Account
Nitro-methane is an additive added to glow fuel in varying percentages, including none. Some engines are very happy with zero percent nitro.
Stab.: is an abbreviation of the word stabilizer and the word stab. generally pertains to the horizontal stabilizer.
Dihedral: given in degrees or inches in models, is the angular difference of the port and starboard wing panels and refers to the height of the wing tips, in comparison to the the center of the wings.
F3D: Is about fast airplanes, not into this, so someone more knowledgeable needs to better define this for you.
Barn Door: is a type of aileron. Barn Door Ailerons are generally located out near the tips of the wings as opposed to Strip Ailerons, which run most of the trailing edge of the wing.
Mixing: Mixing is a combining of channels to remedy a specific problem. Probably the first Mixing situation that a flyer might face is mixing some rudder into ailerons to over come adverse yaw. When banking an airplane, sometimes the down aileron causes more drag than the up aileron. This pulls the nose of the airplane towards the outside of the turn. This can be overcome with a small amount of rudder pushing the nose into the turn. This is only one example of mixing. Mixing will become more important, as you learn to do more aerobatics.
Last edited by Mode One; Jan 18, 2014 at 07:15 AM.
Jan 21, 2014, 01:29 PM
Master of the Figure "9"
hogflyer's Avatar
Here's a few more:

Datum: A reference point or line to base other measurements or locations from. Datum lines generally are looked at running down the length of the fuselage in the X axis and used to set the incidence of the wing(s) and stabilizer, and the engine up or down thrust angles.

Decalage: The angular difference between two airfoils or fixed control surfaces. The most common reference is the angular difference between the wing and horizontal stabilizer, usually expressed in degrees, but sometimes in inches or millimeters. Decalage can also be referred to as the angular difference between the upper and lower wings of a biplane.

Angle of Incidence: The angular difference between the centerline of the airfoil and datum reference line of the fuselage. Example: the center line of the airfoil raised 2 deg. at the leading edge would produce an angle of incidence of +2 deg. When centerline of the airfoil is set parallel to the reference datum line of the fuselage, then the wing is considered to at 0 deg. incidence, or 0-0.

Wash-out/Wash-in: The amount of twist in a wing from the root to the tip. Wash-out referres to the trailing edge of the wing at the tip being higher than the leading edge. Wash-in is the opposite with the leading edge higher than the trailing edge. Wash-out is good as it reduces tip-stall and increases stability in some models while wash-in is bad as it'll induce the tip to stall before the center of the wing which is a bad thing.

Hogflyer
Old Feb 18, 2014, 05:55 PM
BradLeBlanc76
A moderator felt this post violated the following rule: Personal Attack. It is temporarily hidden while BradLeBlanc76 edits it.
Jul 08, 2014, 10:12 AM
Registered User
lukes221's Avatar
A slight correction, not to start anything.

Dihedral: is as described by Mode One, however it is typically when the tip of the wing is above the root of the wing. As in if you look at the plane from the front the tips of the wings will be up in comparison.

Anhedral: is written exactly the same as Dihedral but it is where the tips are down in comparison to the wing root. Respectively if you look at the plane from the front the tips will be down in comparison.
Last edited by lukes221; Jul 08, 2014 at 10:18 AM.
Jan 21, 2015, 05:04 AM
Youtube channel : solentlifeuk
solentlife's Avatar
Just to ressurrect and get pot boiling again ..................

Diesel Engine .... is a term based on a Persons name : Diesel and in fact is NOT the correct term for such engine. It is purely an accepted term by common usage.

The correct term is Gasoil ... and the engine is a COMPRESSION IGNITION engine as against a SPARK IGNITION in a petrol / gasoline engine.

GASOLINE is a correct term as PETROL ... BENZIN ... GASOLINE are geographically localised correct names for the same fuel. (I am fully aware that BENZENE is actually a specific other product but many languages such as Russian use the term Benzin for gasoline).

Just commenting after reading this historic thread !!

Nigel
Apr 22, 2015, 04:25 AM
Closed Account
The name Benzin(e) was derived from the family name of Karl Benz, who constructed the first automobile... "Benzin" was the fluid it ran on, and AFAIK it was quite different from what we now know as Benzin or pertrol or gasoline....

Brgds, Bert
Apr 22, 2015, 07:00 AM
I bail out, anywhere, anytime
Taurus Flyer's Avatar
Quote:
Originally Posted by Brutus1967
The name Benzin(e) was derived from the family name of Karl Benz, who constructed the first automobile... "Benzin" was the fluid it ran on, and AFAIK it was quite different from what we now know as Benzin or pertrol or gasoline....

Brgds, Bert
Bert, from wikepedia,

Dutch
Hoewel zelfs in Duitsland het verhaal gaat dat benzine afgeleid zou zijn van de naam Benz, bestond in werkelijkheid de term benzine al voordat Benz de auto had uitgevonden (1885).

English
Although even in Germany the story goes that benzine would be derived from the name Benz, in reality the term benzine was there even before Benz invented the automobile (1885).


Benzine-engine?

In 1864 developed the Austrian Siegfried Markus the first ''benzinemotor'' of the world.

Taurus Flyer
Apr 22, 2015, 07:42 AM
Closed Account
Who else but Quagmire? Like a moth to a flame....
Last edited by Brutus1967; Apr 22, 2015 at 08:08 AM.
Apr 22, 2015, 08:28 AM
Youtube channel : solentlifeuk
solentlife's Avatar
Benzine was an additive to National Benzol Petrol in UK for years ... many people swore by it. Unfortunately Benzene is highly Carcinogenic and was banned from general use.

It is still used in refinerys etc. as a 'spiking agent' principally in Cat Cracking Gasolines ... or another Pyrolysis Gasoline ....

But we are getting away from the fun !!

Nigel
Apr 22, 2015, 08:48 AM
Closed Account
That would be "Benzene", not "Benzine"

Benzine is the dutch term for the fuel, Benzeen the dutch term for the aromatic hydrocarbon.

Brgds, Bert
Apr 22, 2015, 09:04 AM
Youtube channel : solentlifeuk
solentlife's Avatar
Quote:
Originally Posted by Brutus1967
That would be "Benzene", not "Benzine"

Benzine is the dutch term for the fuel, Benzeen the dutch term for the aromatic hydrocarbon.

Brgds, Bert
Sorry my post was a bit poor .. if you go back to it - you see the change from ZINE to ZENE ... I meant to mention and highlight that.

The Benzine additive was a product with high % of Benzene ... so high in fact as to be near enough straight Benzene.

Not only have I worked ashore with the stuff .... I also carried thousands of tons of the stuff in my shipping career ... some of the Pygas was over 70% Benzene ... some levels totally outlawed today !

Nigel
Apr 22, 2015, 09:35 AM
Closed Account
We still carry it... as well as Nitrobenzene and other nasty concoctions...

Brgds, Bert


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