I bought a Mini Max 1100 with Hirth F33 engine from a salvage yard near Fort Worth.  Only 100 hours on the engine but it sat in the storage barn 3 years.  Recreational Power in Ohio says I should ship it to them for inspection before I run it, to check for internal rust.  Fine, but that means taking the engine off the airframe and that means removing the prop.

The prop is an IVO three-blade ground adjustable ultralight prop.  Replacement would cost $750.  I don't want to wreck it.  There's one huge nut in the middle.  Just unscrew it?  Anything to know, any traps to avoid before I start yanking on the wrench?

Take lots of images. Loosen the large lock nut and turn the large bolt until the friction is at its lowest (middle of travel). Mark the position of the blades  Remove the  six bolts around the circumference. Remove the plate with the large bolt, carefully remove each blade, Remove any spacers. Be careful not to run your hand up and down the trailing edges of the blades (they may have splinters). Store all the parts. IVO has a website with all the info you will need. Consider replacing the steel leading edge guards when you reassemble the prop.
It is a great prop and IVO gives great service.
Joe

I second what Joe spoke about. I run a three blade Ivo on a 447. They have always been good to deal with in my experience.

If you choose to put the prop back on please check with Ivo on the torque for the bolts that mount the blades.

I second what was said above.

Actually I believe it is a large hollow stud if you will (vice a bolt).  Loosen the lock nut (which it may not have) then screw the stud in or out slightly (could be either direction) until resistance goes to zero (and the stud is then loose by about 1/2 turn).  Should not be pre-loaded by more than two turns in either direction.  Once this happens the pre-load is off the blades.  Then one at a time slowly start to loosen the perimeter bolts. I usually do this in a crossing pattern little by little (just the reverse of tightening sequence).

Just my 2 cents worth however.  I quick call to IVO would give you the 100% scoop.

Holy cow, I'm glad I asked.  This is a lot more complicated than I expected.  Thanks for the advice!

I'm very glad to see people pitching in here with good thoughts on the Ivo-Prop.  Awhile back a fellow was asking what prop he should use and I recommended he think about an adjustable Ivo-Prop so he could find the exact right pitch for his aircraft.  These aircraft vary a LOT in drag depending on how people approach building their particular aircraft.  He pretty well trashed my answer on the grounds that he just wanted the "right" answer for pitch for a mini-max.  It looks like you've tapped into some readers who really know these props inside and out and can really help you in detail.  That will make it much easier to learn to get the exact best setting on your prop.

Tom

More questions.  I saw a technical bulletin on the IVO prop website about adding metal tape over the joints of the blades.  Not clear if that applies to Hirth F33 engines?  Here's a photo of my prop.  What are you guys doing with yours?

Please see:

http://www.ivoprop.com/servicebul2.htm

If you fly you should always stay current on the latest Service Bulletins, Airworthiness directives, etc.

Joe

I'll get in touch with IVO.  Thanks for the suggestions.