I 4-2-4'd a Cox

RknRusty wrote:The Clown?

Yep, strange eh?

I was flying with some older dudes who are amazingly good flyers, I told them to have a go with the Clown. Nope! "too fast" I was told.

Too fast! What a buncha wusses. A good running 1/2A can separate the pilots with guts and skill from the wannabes. Sure precision stunt takes skill, but guts commands respect.

RknRusty wrote:Too fast! What a buncha wusses. A good running 1/2A can separate the pilots with guts and skill from the wannabes. Sure precision stunt takes skill, but guts commands respect.

I bet these guys could have flown it easy. I would love to be able to fly like them. 1/2A is fast compared to the big guys.

One of them brought a Jr. Ringmaster. I should have taken a picture as I brought my S1 and Baby Ring.

Glad the clown's a quick one Ron!

nitroairplane wrote:Glad the clown's a quick one Ron!

It's actually my best flyer. It always keeps tension and does what I ask it to do. Thanks Indra!!

When I flew competative stunt eons ago in Class B, 2-4-2 was standard practice though some engines were better at it than others. The larger planes have the wing area and longer lines that clause them to fly relatively slower than 1/2A's giving the pilot greater time to plan and react to manuvers.

In times past my favorite plane/engine combo was a Kenhi "Cougar"/ Veco .35 w/54" span and flaps. (It's still in my family today needing re-covering) BTW, the Kenhi "Cougar" is in production still today.

SD

I know I'm not savvy on all of the CL lingo... what is a 4-2-4?

Travis:

re: 4-2-4 = four-cycle/two-cycle/four-cycle

The engine needle is set to allow the engine to run slightly rich, then break into two-cycle during manuvers then return to four-cycle.

Four-cycle slows the the engine speed and plane in straight and level flight. When a manuver, like a figure 8 is entered the engine leans out to run at "full scream" with full plane speed. When the manuver is complete the engine returns to four-cycle and slower plane and engine speed.

The trick is to "needle" the engine correctly which takes pilot experience.

SD

ok, what does cycle mean.. I guess I'm still not quite following...

So, Ron did 4 laps - 2 maneuvers - 4 laps.... is that right?

I'm one of those kids that knows what a 3s4500 means

Or is a 4-2-4 mean:
Rich-Lean-Rich...
Slow-Fast-Slow....
So, I guess it speeds up for the maneuvers???

2-4-2:
Fast - Slow - Fast... I guess it would slow down for the maneuvers???

My guess on cycle would be the sound difference between a 2-cycle and 4-cycle engine?

Travis:

Four-cycle = the engine fires every other time the piston reaches TDC (top dead center) with slower RPM reached. (This is due to the richer fuel mixture)

Two-cycle = the engine fires EASH time the piston reaches TD with engine to run at full speed. (This is caused by the leaner fuel mixture)

SD

I guess I didn't know a Cox would fire as a 4-stroke... being that it's designed as a 2-stroke...

Travis:

Yes, manuvers are better and more gracefully done at the slower speed largely to the the wing area of large planes.

SD

I dunno... logically it doesn't make sense... (4 cycle - 2 cycle)

I can see that when pulling a maneuver that the engine would lean out. So if your rich and pulling a maneuver it would lean out.

Now if your NV is in it's sweet spot, I guess that would be more lean then rich, so when you would pull a maneuver, the engine would go leaner which would slow the engine down because it's starving???

Not really "starving" but leaning out.

I you think about for a time it'll make sense.

SD

Ya, if you run the sweet spot and then go leaner, it's really starving for fuel.

When flying full size, you richen the mixture for any take-off/landing or close to earth maneuvers. If you don't the engine could lean out and stall, which will be bad at lower altitudes.

WingingIt74 wrote:I guess I didn't know a Cox would fire as a 4-stroke... being that it's designed as a 2-stroke...

Not only a Cox but other two-cyles will too i.e. a chain saw. It has to do with the porting on a two-cycle (aka: two stroke)

SD

I dunno about that... seems a little weird to me.

Travis:

Sorry, my bad. Got the numbers reversed (but at least I got you thinking)

Make that 2-4-2. (The memory is the second thing to go)

SD

a 2-4-2 would slow for maneuvers, correct?

I still don't see how how a 2S can act like a 4S, that has to do with timing. A 2S has a constant timing, which fires at every TDC.

Here's a 2-4-2

As I understand it a 4-2-4 means it runs rich during level flight (4) leans out when the nose of the plane goes up (2) goes back to normal in level flight (4) i never understood why it's often referred to as 2-4-2. It's basically the sound the engine makes. Rich lean rich etc.

Ron

An over-rich two stroke glow engine will commonly fire every other revolution. This is known as 4-cycling, or 4-stroking. There is some debate as to what causes this. The theory I subscribe to is:

A rich mixture does not burn completely, and two strokes don't have great exhaust scavenging. The left over fuel vapor contaminates the next charge, making it to rich to ignite. While this mixture does not ignite, it does serve to clean out the cylinder so that the next charge does ignite. The engine ends up firing on alternate revolutions.

To get a 2/4 break for stunting, the tank is mounted a little below the spray bar. This makes the engine lean out a little when pulling Gs.