Draker
Well Known Member
Kind of scratching my head at this one. Has anyone encountered an incorrectly sized spinner cone from Vans? Quoth the plans:
OK, so I'll measure the prop hub first. The distance between the aft side of the front bulkhead and the aft edge of the aft bulkhead is exactly 9" on my (Hartzell CS) prop:
Now, I take off the front bulkhead and position it inside Vans spinner cone so that it is exactly perpendicular to the centerline of the cone. Measure the distance between the aft side of the front bulkhead to the plane of the spinner cone edge. Oh, no, it's 9-1/4":
To verify this, when I mount the cone over the bulkheads attached to the prop, the cone is exactly 1/4" too long.
Vans:
Sounds like I might need 1/4" of these spacers. But, wait: Van's spinner drawing describes building up a few layers of fiberglass to make up for small gaps. Breaking out the trigonometry, given the spinner cone angle in that location, I would need to add about 7/64" of fiberglass to the inside of the spinner to make the bulkhead snug. That seems to be a lot of lumpy weight to add to the fastest-moving piece of the airplane. I suppose I could also carefully trim 1/4" off the aft end of the spinner cone, too.
If you also encountered this, what did you do?
Before installing the S-602-1 and S-605 (or S-605SEN) spinner mount plates to the prop, fit them to the spinner. This will verify that the prop hub thickness corresponds to the relative diameters of the mount plates. [...] When both the front and rear plates are aligned with the spinner and with each other, the distance between them will be the required thickness of the prop hub.
OK, so I'll measure the prop hub first. The distance between the aft side of the front bulkhead and the aft edge of the aft bulkhead is exactly 9" on my (Hartzell CS) prop:
Now, I take off the front bulkhead and position it inside Vans spinner cone so that it is exactly perpendicular to the centerline of the cone. Measure the distance between the aft side of the front bulkhead to the plane of the spinner cone edge. Oh, no, it's 9-1/4":
To verify this, when I mount the cone over the bulkheads attached to the prop, the cone is exactly 1/4" too long.
Vans:
If the distance is greater than the thickness of your prop hub, spacers may be installed between the front plate and the forward surface of the prop. These spacers are available through Van's Accessories Catalog.
Sounds like I might need 1/4" of these spacers. But, wait: Van's spinner drawing describes building up a few layers of fiberglass to make up for small gaps. Breaking out the trigonometry, given the spinner cone angle in that location, I would need to add about 7/64" of fiberglass to the inside of the spinner to make the bulkhead snug. That seems to be a lot of lumpy weight to add to the fastest-moving piece of the airplane. I suppose I could also carefully trim 1/4" off the aft end of the spinner cone, too.
If you also encountered this, what did you do?
- Get 1/4" spacers (part #??) and longer attach bolts for the front bulkhead
- Carefully lay up 7/64" of fiberglass inside the spinner cone
- Trim 1/4" off the aft end of the cone
- Any other options???