Tipsy Nipper

Hi all,

I need to remove the prop driver from a VW 1834 engine (SAUER conversion) fitted to G-AVKI. Can anyone point me in the right direction, i.e. is the big nut a R/H or L/H thread and is there an easy way of locking the crank to prevent rotation?

Thanks in advance

PS, despite repeated e-mails to SAUER, I've never had a reply, nor do I have a manual! Can anyone help - even a similar manual would be better than nothing!

Hi Gary,

The prop' bolt is a normal right hand thread. The flange should be a heat shrink fit, and you may distort it if you use a normal two or three leg puller. The best way to remove it is by using a press with the crank out of th engine. If the crank is still in the engine I have a tool you could use to pull it.

If the flange is not a shrink fit I personally would not re-use it. There are ones about that are "slip on", but I believe there have been issues with crank failures. Barry Smith would be a good person to consult on that one.

A tool to counter hold the crank flange is easy to make. A long flat bar about 30mm x 8mm x 1m long with another lever 200mm long bolted to the end of it to create a Y at the end. Holes drilled in the ends of the Y locate onto the holes in the prop' flange by bolts. I have just loaned my tool to a friend so am unable to photograph it for you. I hope you understand my description.

I am not personally familiar with the Sauer conversion, could you post a photo?

Neil

Hi Neil,
will take some pics next time I'm down at the airfield; I don't think the SAUER conversion is anything special, just a twin plug head and some adaptations for the intended role in an aircraft. It was originally fitted to a Falke motorglider.

Once the prop and the alloy spacer was removed, I unscrewed a long allen headed bolt from the centre of the prop driver, this is in the centre of what appears to be a large (about 30mm) hex headed 'bolt'. Am I correct in thinking that this 'bolt' isn't actually screwed onto anything, but is a push fit (onto a splined shaft perhaps?) which can be removed with a puller?
I don't think that I'll distort my prop driver with a puller as it's a fairly substantial piece of machined steel - I need to remove it so that I can assess/remove some surface corrosion.

I was hoping there's be something simple like a rigging hole to lock the engine,
but I can picture your special tool to prevent rotation perfectly; should have thought of it myself.
Sorry if my description's a bit diffcult to interpret; I know what I'm talking about though

cheers

Gary T

PS, do you have any details about the aircraft fitted with bungee donuts instead of multiple rubber rings? I'd like to do the same if possible and life would be much easier if i can point to an existing mod.

Gary,

Confirm R/H thread. Rollason used 0.002" interference fit on their engines. The prop hub was heated in an oven before being offered up.

David G-ARBG

microlightgary wrote:PS, despite repeated e-mails to SAUER, I've never had a reply, nor do I have a manual! Can anyone help - even a similar manual would be better than nothing!

Could be worth speaking to Dave Allen at Rufforth 07973 765552

He had a go at retailing Sauer engines, as he was so impressed with them, but they weren't interested. However, he does have contact details (I think).

Bugger, mine doesn't look anything like that David! Will have to take a picture when I go to the hangar.

Spot,
thanks for the contact details, will give him a call

OK, here are some pics of the SAUER engine and the prop driver. You can see from the surface corrosion why my inspector wants it removed.
Not sure what exactly the allen bolt down the center is screwing into, or its purpose really.

Hi Gary,

Thanks for posting the photos.....it's amazing how different all the Nippers are!

I personally think you are opening a can of worms by removing the prop' hub. May I suggest you ask your inspector if he REALLY needs the prop' hub off, or if you can't just remove the rust by rubbing it down with emery cloth and repainting? You will need to ensure no debris enters the front of the engine via the gap between the hub and the front of the crankcase. This could be done with some string wrapped around the hub up close to the crankcase.

I would think the large bolt is the same as my 1834 engine, in that it is a normal RH thread, and the allen bolt is actually a locking device of sorts.

Barry Smith may have more info', if you don't have his tel no then pm me and I will forward it.

Neil

I managed to remove the bolt today but I also spent quite a while sanding the corrosion off. Am hoping that I can convince the inspector that it's serviceable! It's come up quite well so far - will do a before and after photo. A good tip about the string Neil, thanks for that.

Getting there! Still some more wet & dry to go through...

.......by the way, I see you are running an Ellison TBI.....do you have inverted oil as well?

Neil

Hi Neil,
unfortunately no inverted systems, just an entry in the original logbook stating that the original (bing) carb was replaced with the Ellison throttle Body.

Good news - G-AVKI had her Permit re-inspection today. All went well and thankfully he was more than satisfied with my efforts at removing the corrosion from the Prop driver so thanks to all for their advice.

All things being equal (and assuming we get some decent weather soon!) KI should be airborne for the check flight shortly and fully Permitted soon thereafter.
Here's looking forward to the Old Warden Nipper gathering

cheers

Gary T