Good link to a nitro starter

[waveydavey]

It connects through the clutch stack, the clutch engages centrifugally when you spin the engine with enough revs. The shaft you are spinning in order to start the engine goes through the centre of the clutch to a one way bearing in your case on the 600. This engages in order to spin the engine and then once started can stop because of the one way.

[Keratos]

Erm, nope, still dumb on this side of the brain. I reckon I'm going to try to google something about this to discern how this works. Interesting though and as an Engineer (albeit Aerospace Software / Systems) I do like to suss how things work.
Cheers anyway for trying to explain to the uneducated

It connects through the clutch stack, the clutch engages centrifugally when you spin the engine with enough revs. The shaft you are spinning in order to start the engine goes through the centre of the clutch to a one way bearing in your case on the 600. This engages in order to spin the engine and then once started can stop because of the one way.

[hedge]

Your in luck you've got a Trex 600 the clutch has a one way all you need is a solid wand to go with the dynatron you need to buy.

In this hobby there is so much to learn without worrying about stuff you don't need to know. get spending, start flying and concentrate on what you need to know. Then in a couple of years you can come back to all this unnecessary stuff :-)

if your bored start reading about changing engine bearings and resetting throttle linkages as i can almost guarantee this will be needed either straight away - you say the helis been sitting around - or within the next 2 or 3 gallons.

[Keratos]

get spending, start flying and concentrate on what you need to know. Then in a couple of years you can come back to all this unnecessary stuff :-)

LoL - Sounds familiar

[helijohn]

Erm, nope, still dumb on this side of the brain...................
Cheers anyway for trying to explain to the uneducated

As an engineer I am sure you would have come across this concept particularly in aerospace developments and can grasp this concept easily. You need to research sprague bearings if you are going to Google it.One way bearings - HeliFreak

Something you may not have grasped is that when the engine starts it revs like ****. It goes faster than the rev capability of the starter. The one way gear on the clutch shaft (or the wand or both) allows the engine to go/rev faster and thus ahead of the revs of the starter as it only grips when being driven. Don't forget the clutch bell is connected to the blades via a pinion and drive gear and the clutch shoe is connected permanently to the engine (a bit like a car's manual gearbox).


This may not be the best analogy but...........If you ride a pushbike which is not fixed wheel then when you have stopped applying torque to the chainwheel (via the pedals naturally) you can freewheel. So imagine if you will that a big starter (or motor) is attached to the centre of the chainwheel (at the crank spindle) and is used to turn the crank/chainwheel/pedals or whatever to drive the bike forward. When the speed of road wheel is faster than the chainwheel is revving at (and thus the starter) your bike freewheels. In short the starter is no longer driving the bike along.

In some mowers there is the same clutch shoe setup as in the heli but the engine driving the mower is permanently attached to the clutch/shoe as it is never anticipated the engine will go slower than the mower it is propelling except when throttled back of course which then disengages the clutch to allow the engine to idle free of the encumbrance of the mower (blades and roller) so it can come to a halt.

Might I suggest some bedtime reading such as Ray's heli manual or an equivalent.

[Keratos]

As an engineer I am sure you would have come across this concept particularly in aerospace developments and can grasp this concept easily. You need to research sprague bearings if you are going to Google it.One way bearings - HeliFreak

LoL
thanks anyway - I am a software and systems design engineer , not mechanical engineering. Can waffle for days and hours on C++, ADA, OOP, OOD, Operating systems, Event drivemn architecture, windows stack, DLLs, sensor fusion, programatics and logic - but sorry, no can do mechanicals.
I have found this
Understanding one-way bearings - Page 1 - RunRyder RC Helicopter
but that still doesnt explain to me how this benefits the starter and allowing the engine and starter to rev at different speeds

Don't forget the clutch bell is connected to the blades via a pinion and drive gear and the clutch shoe is connected permanently to the engine (a bit like a car's manual gearbox).

absolutely in russian to me - sorry

Might I suggest some bedtime reading such as Ray's heli manual or an equivalent.

yes - if I knew where to find it - google no doubt. thanks for the tip

[helijohn]

yes - if I knew where to find it - google no doubt. thanks for the tip

RAY'S AUTHORITATIVE HELICOPTER MANUAL - Your Complete Guide to Successful Model Helicopter Flying: Amazon.co.uk: Ray HOSTETLER: Books

Did you not get the bicycle analogy??? I expect you have ridden a bike downhill and freewheeled to save your legs keeping up with the road wheels!

[Keratos]

cheers
I like watching the youtube vids as well, that explain in animation terms, how "stuff works".

RAY'S AUTHORITATIVE HELICOPTER MANUAL - Your Complete Guide to Successful Model Helicopter Flying: Amazon.co.uk: Ray HOSTETLER: Books

Did you not get the bicycle analogy??? I expect you have ridden a bike downhill and freewheeled to save your legs keeping up with the road wheels!

[Keratos]

EDIT 22:05

The one way gear on the clutch shaft (or the wand or both) allows the engine to go/rev faster and thus ahead of the revs of the starter as it only grips when being driven.

but the one way bearing prevents (locks) rotation of the main gear in the anti clockwise rotation (assuming - as is in my bird - that the blades rotate clockwise). The one way bearing is inside the main gear. The main gear is driven by the clutch gear. The clutch houses a centrifugal mechanism that engages at a certain engine RPM. This turns the clutch bell that in turn operates the clutch gear. The starter coupling is attached to the clutch gear. There is no direct mechanical interaction between the one way bearing (in the centre of the main gear) and the clutch gear (that interacts with the teeth on the main gear)

Consequently the one way bearing has nothing to do with the clutch - not according to how I read the manual in front of me. Its purpose is to allow the autorotation gear to rotate if there was no power to the main gear.

So what has a one way bearing got to do with allowing different revs , he ponders? Argghh - I wont let this go 'cos I do not understand and its in my nature to understand such interesting and detailed concepts - this is what I relish. Ah well, bed now, I shall pick this subject up and try to find some good vids. Many thanks John for trying to educate.

EDIT#2: Actually, do i need to start a new thread about one way bearing as this is sliding off topic some may feel??? not sure?

[helijohn]

EDIT 22:05


but the one way gear prevents (locks) rotation of the main gear in the anti clockwise rotation (assuming as in my bird the blades rotate clockwise). The one way bearing is inside the main gear.
Nope, the starter one is under the clutch bell. The one way bearing we are discussing is for starter purposes though there is one in the main gear as well for autos etc.

The main gear is driven by the clutch gear. The clutch houses a centrifugal mechanism that engages at a certain engine RPM. This turns the clutch bell that in turn operates the clutch gear.

Nope. When the clutch bell housing is engaged and spinning it is turning the blades by a pinion (on top of the bell) and a gear and does nowt else.
The starter coupling is attached to the clutch bell.

Consequently the one way bearing has nothing to do with the clutch - not according to how I read the manual in front of me. Its purpose is to allow the autorotation gear to rotate if there was no power to the main gear.
That is another sprague bearing and another issue.

So what has a one way bearing got to do with allowing different revs? Argghh - I wont let this go 'cos I do not understand and its in my nature to understand such interesting and detailed concepts - this is what I relish. Ah well, bed now, I shall pick this subject up and try to find some good vids. Many thanks John for trying to educate.

So it seems you are focusing on the mainshaft sprague and you need to forget that one for this discussion.

[waveydavey]

Your 600 has a one way in the main gear and also a one way in the clutch itself. The one in the clutch allows the operation of the starting mechanism by grabbing the starter shaft whilst being span in that direction (ACW from above) and releasing it once the engine starts to drive, IE the clutch then overtakes the starter (because you've heard the engine and stopped pressing the button on the starter). The one in the main gear allows the blades to freewheel if engine power is cut for some reason, or if you cut it allowing an autorotation

[Keratos]

Hi John, well looking at the drawings which i can read and understand - thank god - the clutch bell surrounds the clutch gear, which rotates inside a normal bearing (not one way), which is secured by a clutch nut which sits under another normal bearing (not one way) which sits under the starter coupler. This is very clear in the Trex Nitro 600 manual in front of me.

The index pages identify only one "one way bearing", 18x16mm, p/n 50B049-1, just the one, and nothing to do with the clutch. It sits inside the main gear. around the one way shaft that drives the main shaft. The main gear is driven by the clutch gear. there is no other one way bearing?

EDIT. Talking bollocks. There is another one way bearing, P/N 50NHF1012 inside the clutch, tiny, but its there. so I need to analyse this and understand. Ohhhh the fun. I stand corrected.

[helijohn]

The transmission chain.
The engines starts and at revs will throw out the clutch shoe to grip the clutch bell. The bell then starts turning (with the same revs as the engine) and the pinion on top of the bell (which is pre engaged to the main gear) makes the main gear turn as well. The main gear is attached to the mainshaft so the mainshaft turns as well and voila the blades rotate.
The pinion is on a shaft which goes down to the clutch which is where the sprague is actually is found - in the clutch shoe!
To start, you plonk the starter wand on the top of the pinion which is on the top of the clutch bell BUT the shaft used goes through a sprague bearing so when the clutch, the bell and it's pinion is turning and is going faster than the wand the sprague lets go.

[waveydavey]

This is the bearing in the clutch made by INA HF1012

http://www.vxb.com/Merchant2/graphic...-one-way-1.jpg

[Keratos]

... and this prevents the shaft taking off and inserting itself in your eye socket or converting ones two blade arrangement into several shorter blades!!
Got it.
Phew!
Hard work arent I
Sorry - I just cant help myself , this sort of stuff interest me - sad eh.
Okay, i can sleep now.
Nitey
thanks John

The transmission chain.
The engines starts and at revs will throw out the clutch shoe to grip the clutch bell. The bell then starts turning (with the same revs as the engine) and the pinion on top of the bell (which is pre engaged to the main gear) makes the main gear turn as well. The main gear is attached to the mainshaft so the mainshaft turns as well and voila the blades rotate.
The pinion is on a shaft which goes down to the clutch which is where the sprague is actually is found - in the clutch shoe!
To start, you plonk the starter wand on the top of the pinion which is on the top of the clutch bell BUT the shaft used goes through a sprague bearing so when the clutch, the bell and it's pinion is turning and is going faster than the wand the sprague lets go.