Rotax E Gearbox - Sprag Clutch ?

[boleropilot]

G'day All,

 

Recovery from that little altercation with terra firma a month ago is progressing better than expected, so sale of 0455 is on the back burner for the time being - time will tell...getting the 'new' 582-99 fitted to 0455 is now the priority.

 

Today I discovered that the spare gearbox that came with the aircraft (and has been sitting in a box attached to an out of hours 582-90 that came with the aircraft) is in fact an E type. Just wondering if anyone has any information they would like to share with respect to the Sprag Clutch that is usually fitted to E boxes - I've been doing some serious googleing to find out what I can, tomorrow I will be removing the 'box from the motor and having a peek inside to see if the sprag clutch is fitted, and if so, try to determine the state it is in.

 

Any information most appreciated - I've read a fair bit about how they work and the drama they can cause, but I'd love to hear some comments from those who have had hands on experience with these (especially if fitted to a 'box bolted to a 582 motor).

 

cheers,

 

BP

 

 

[boleropilot]

well this is going to be a fun changeover - just looking at the way the standard two radiator system has a joining hose that goes from the base of each radiator to each other, that is where the starter motor is situated with the E box - so where does the joiner hose go when using a E box? maybe just a longer hose that is fitted under the motor out of the way?

 

funnily enough, the three radiator system that was fitted to 0455 (look at the setup on the Ant's Aircraft Drifter) and it looks like I will have to stick with the three radiator setup anyway - goes well with the E box

 

come to think of it the original 582 fitted to 0455 did have this E box as original, so maybe that's why they went to the 3 radiator setup in the first place?

 

I'm so confused...as far as the sprag clutch is concerned it seems to be a 'good idea' as long as certain parameters are met, including a big fat healthy battery for all starts to avoid damage to the sprag clutch

 

but wait, there's more -

 

BP

 

 

[M61A1]

G'day All,Recovery from that little altercation with terra firma a month ago is progressing better than expected, so sale of 0455 is on the back burner for the time being - time will tell...getting the 'new' 582-99 fitted to 0455 is now the priority.

 

Today I discovered that the spare gearbox that came with the aircraft (and has been sitting in a box attached to an out of hours 582-90 that came with the aircraft) is in fact an E type. Just wondering if anyone has any information they would like to share with respect to the Sprag Clutch that is usually fitted to E boxes - I've been doing some serious googleing to find out what I can, tomorrow I will be removing the 'box from the motor and having a peek inside to see if the sprag clutch is fitted, and if so, try to determine the state it is in.

 

Any information most appreciated - I've read a fair bit about how they work and the drama they can cause, but I'd love to hear some comments from those who have had hands on experience with these (especially if fitted to a 'box bolted to a 582 motor).

 

cheers,

 

BP

Sounds like you need to talk to a Dragonfly driver. There's a couple that tow hang gliders at Dalby they have clutches in them, not sure why or what advantage.

 

 

[skippydiesel]

Hi Bolero - I replaced the sprag clutch on my Rotax 912 ULS about 12 months ago. Pretty straight forward, as long as you follow the step by step instructions in the manual.

 

As you have intimated, the life of your spragg clutch is, in part, associated with having plenty of battery cranking amps (CCA).

 

I have never understood why people use batteries with marginal CCA or persist with a dying battery. The potential damage to your starting system is far more costly than having a good battery with plenty of CCA.

 

These days battery technology has improved by leaps & bounds. You can now get a lighter battery with higher CCA for almost all applications.

 

If battery weight is a Cof G consideration, get the same weight with vastly greater CCA.

 

 

[boleropilot]

thanks Skippy - I might have to take that message off my bullbar now = HERE SKIP

 

as far as I can determine (not many replies indicates a distinct lack of knowledge here) the motor should start easier because the starter motor only engages the main gears and propellor after X amount of revs are reached - there should also be a smoother idle because of the same process - once X rpm is reached the moving gadgets (I think they're called sprags) expand out via centrifugal force and thereby engage a gear that is on the shaft that connects to the gearbox main gears and propellor. Apparently this is the case with the aftermarket RK400 clutch that fits C gearboxes (it don't fit the E, maybe because the sprag thingy is already there?).

 

I've seen video of a 582 with C box idling and the noise is so different and quiet, also the prop doesn't actually move until revs are increased - apparently this is a big deal for acft on floats for mooring (I get that).

 

Would LOVE to hear from any 582 owners with an E gearbox fitted - or am I the only one???

 

BP

 

 

[M61A1]

I think what you are referring to is a "centrifugal clutch". The E gearbox has a sprag clutch for the starter motor only just like a lot of modern motorcycles.

 

RK 400 clutch, Rotax clutch, clutch for Rotax C drive, centrifugal clutch for Rotax C drives.

 

 

[boleropilot]

the E box is now completely removed and disassembled for checking out and finally fitting to the 582 I got from Clifton

 

everything inside is in A1 condition so it is a relatively simple matter to do that - as above, the only drawback is how the radiator lower connection pipe is routed

 

there may also be an issue with the starter motor clearing the engine mounting frame, I've been told that is not likely to be a problem because the frame was designed to accept all gearboxes - we shall see!

 

btw, one of the benefits of the E box is that with the mounting of the starter motor at the back of the engine it is possible to have the pull starter system on the front as a backup - nice...

 

hoping to have both motor and gearbox mounted within a couple of weeks - watch this space

 

BP