Engine revvvving but no

[jamiesawyer28041978]

Raptor was running fine last night had a few flights all was well , started up normal tonight everything fine reves up but the disk was hardly turning at all . Had the engine out tonight and checked the clutch and everything but no idea what is causing this. Any ideas welcome please . ( just put a new clutch and bell in it two weeks ago.

Regards jamie

[Steve]

Engine was possibly running backwards - the disk won't spin as the clutch won't engage, and it will rev its txts off!

The engine can fire backwards if you remove the starter wand too quickly, and it can run backwards after a lean-out at the end of a tank.

Or, you had your starter plugged in the wrong way around?

[jamiesawyer28041978]

Thanks for that , didn't know that an engine can start the wrong way but im prety sure the starter was the correct polarity . Ill try it again tomorrow morn , bit dark now .The engine was sounding normal to me , would the timing not make it sound like it was running hellish .

[jamiesawyer28041978]

Disk was turning in the correct direction too

[Steve]

They usually sound exactly the same backwards as the do when going the right way, they just tend to rev hard because the clutch doesn't engage so there's no load on the engine.

[nightstalker]

Thanks for that , didn't know that an engine can start the wrong way but im prety sure the starter was the correct polarity . Ill try it again tomorrow morn , bit dark now .The engine was sounding normal to me , would the timing not make it sound like it was running hellish .

Yeah every engine can go backwards, when u go into reveres in ur car it does it hence why u go backwards


((sorry))

[jamiesawyer28041978]

funny funny nighstalker but all jokes apart wouldnt the disk turn the different way as to normal clockwise direction

[Ade_Law]

defo sounds like its running backwards. if the engine is overly rich on the idle its quite common for it to start forwards but then switch by itself.

if you have something like a raptor 30 with a non constant drive tail you will see the tail spin backwards when you try to rev it up.

if you have one of the 50s with a constantly driven tail then you will see the main gear spinning but not the head or tail.

what happens is that when you rev the engine up when its running backwards the clutch engages as normal but the auto bearing just spins.

Ade

[Steve]

No - because the clutch won't engage (have I said that already????)

The disc might even turn the correct way just because the wind is blowing it around!

[Steve]

I stand corrected!

Cheers Ade

[nightstalker]

no as u have a one way bearing on the main gearing and it will only engage one way, if u hold of your rotor head and hold the main gear with the other hand and turn it ant clockwise the head will move freely and not make the main gear move, but spin it the other was it will engage the oneway bearing and move the gears,

But yes the engine can run backwards as there isn't anything for timing on these engines it just goes up and down and dont have valves

almost the same as ade said but mine was was better to understand (joke)

[jamiesawyer28041978]

Thanks for the support will check the tail in the future if this happens again

[nightstalker]

give us an update once u have tested it tomorrow so we know ur ok, as we do worry

[jamiesawyer28041978]

Just in , helli is working fine again . Leaned the engine up on the bottom end and rea adjusted the top end and all is well. Can the bottom end screw turn through vibration during time . Must have fired up back wards last night ( didn't know they could do that ). Light is going again and a bit windy but couldn't resist

Thanks for the help again .

Jamie

[Bug]

I fired mine up backwards, wonderd why is wasnt pulling attall as i walked out, tried to start it up and the engine just died, lolz, its one of thoose things you dont realise will happen untill it does