Spinner/cowl clearance

[Dave S]

On our S7, I pretty much stuck to the spacing between the spinner and cowl (about 3/8") in the build manual. The spacing still requires a lot of care when removing the cowl with the spinner in place.

I am wondering what spacing others have used that might make it easier to pull the lower cowl without removing the spinner?

[jiott]

Mine is also about 3/8" and I have to use some care in removing the lower cowl, but it is not too bad; I can do it alone without help.
More clearance would definitely make it easier but would start to look sloppy.
Be generous with the cutout for the exhaust stinger; that also helps. I have over 1000 hours on my original 912uls factory kit exhaust system with no signs of any cracks. I understand that this is quite unusual, but I attribute part of it to a generous exhaust cutout so the pipe never contacts the cowl during a shaky startup or shutdown.

[Dave S]

Hi Jim,

Thanks for your feedback. I've been reluctant to increase the clearance due to the sloppiness appearance factor. I might leave it as is.

I do have a respectable clearance around the stinger and that has worked out just fine.

FWIW, I believe I have a similar vintage (skystar) exhaust system and no cracks or wear so far, although I have fewer hours on the plane than you do. Early on in installing the engine I noticed a small tab welded to the bottom of the muffler on the stinger side. Asking John McBean about that he indicated there should have been a brace to the stinger which he had parts in stock for. Due to the old skystar bankruptcy I was missing several small parts as well as the big stuff so got relatively proficient at sourcing more than a few things.

Fly well