Light Aircraft Association

Hi All,
I have a dream regarding upgrading the spinner on my Jodel 120 and as I know nothing about the process, thought I'd raise a post.

The current spinner is a little semi-sphere on the inside centre of my Evra prop (so no backplate at present). Although I think it'd look even nicer with a big spinner, if the effect would be just cosmetic I'd not bother. I'm imagining it could add ~4knts to my top speed (~100knts at present), and a few onto whatever power I cruise at.
So obvious questions:
1) Is it worth doing (would a big spinner like most Jodels have, improve performance)?
2) I assume this would be a minor mod??
3) Can anyone recommend where to get a backplate/spinner made up?
4) And roughly how much such items may cost (break this one to me gently)?

As ever, I hope I'm not wasting anyone's time and all info is greatly appreciated

Cheers,
Will.

Hi Will, you have a couple of options. Pete Smoothy (Airworld UK) sells a kit which includes pre-drilled front and rear bulkheads to fit the O-200/C90. It is a special order item and I have no idea how much it costs, but it will save you a lot of heartache. You will still need to do the prop cut-outs and the screw fittings that attach spinner to bulkheads, but the critical front bulkhead diameter for an Evra will be correct.
I’m not convinced you’ll get a noticeable increase in speed but they do look nice. I had one of Pete’s spinners on my Jodel, surf for a pic of G-BFGK and you’ll see what it looks like, it has been on there for quite a few years and hundreds of hours without problems.
The other option is to buy a spinner kit from somebody like Aircraft Spruce. They may also have the ability to provide front and rear bulkheads drilled for your prop flange, if not then you are going to have to get it done yourself. Some of their kits do not have front bulkheads but I would not consider fitting a spinner of the size required without a forward bulkhead. In my experience they end up cracking at the forward edge of the prop cut-outs and if the spinner were to break in flight it could do a lot of damage to the prop and/or airframe as it departed.
I wouldn’t drill a bulkhead either unless you have the appropriate equipment – a dividing head for instance – to ensure the bolt holes are perfectly concentric, otherwise it will run out and eventually crack.
The real pain with spinners is getting the correct diameter front bulkhead, you may end up having to space it off the propeller to get it right, and that means spacers and longer prop bolts.
I have no experience with carbon or glass spinners, the latter work well on Van's RVs but you still have the bulkhead problems to resolve.
If you are not already a member of the Jodel Yahoo forum ([email protected]) I'd join it. There are plenty of people on there willing to offer useful advice.
Rgds, Brian

Thanks for all the great advice