Spinner Not Parallel to Cowl

USCANAM · #1 09-08-2007, 02:10 PM

I'm thinking that I came upon a thread way back on the subject where the backing plate/spinner does not have an even space between them and the cowl, but can't seem to locate it.
Just starting to fit the cowl on my 9A and where I have a 1/4" gap at the top, it looks like I'll have over a 1/2" gap at the bottom.
If I remember correctly, some builders were building up the space with fillers.
Would appreciate some input on the subject
Thanks All
Jack

cytoxin · #2 09-08-2007, 03:50 PM

fit the closest side then after the cowl has been fit completely you'll find this gap to shrink considerably. then you can build it up to perfection... if you already have the cowl fittted then yours is the worst ive heard of. mine was very much like you describe when i started. but it is so close now i dont know if i'll bother with it.

MrNomad · #3 09-08-2007, 09:08 PM

Yup, I had a similar problem on a 9A. The large starter gear aligned with the cowl almost perfectly after a lotta work. But then we installed the prop and realized the starter ring gear was not properly in place. Once the prop was torqued, the alignment changed.

&^%$#

Using two engine mount washers, we raised the bottom of the engine and caused the cowl to come back into alignment. There was still a bit of glass work to make it perfect, but the washers reduced the error.

If you don't torque the ring gear to the specified lbs because the prop is not on, at least tighten it to 30 lbs to make sure your target alignment is correct.

Barry

BlackRV7 · #4 09-09-2007, 06:46 AM

Quote:

Originally Posted by USCANAM

I'm thinking that I came upon a thread way back on the subject where the backing plate/spinner does not have an even space between them and the cowl, but can't seem to locate it.

Jack

Jack, my 7 cowl left a little to be desired. Having built a plastic airplane before the 7, the workmanship was overcomeable (is that a word). My bottom cowl was perfectly spaced with the backing plate with an even gap from top to bottom. However, the top cowl piece was almost touching the plate at the top and didn't even line up the the overlaps of the bottom. I ended up having to cut the top cowl ring off, do some cutting and filing then reposition and flox in the ring. Lots of micro work was required to come up with a nice clean cowl around the prop and air inlets. I didn't want to do anything with repositioning the engine as I checked and double check the alignment of it so I knew the engine and bottom cowl were correct. You just may have to do something along my lines.

USCANAM · #5 09-09-2007, 06:48 AM

William and Barry
Thanks for the replys.
I did mount the prop, not that I wanted the 3 blades to be in the way all the time, but since the back plate is mounted to the prop, I had to.
It is torqued right down.
The other day, I even checked the angle of the engine to make sure that perhaps I had a mount that was incorrect, but the thrust line of the engine is the same angle as the main longerons.
At this point, I think I'd rather fill the gap than use washers to change the thrust angle.
Right now I'm thinking about high density foam glued to the cowl front, then shaped.
A couple of layers of glass with epoxy and filler to finish.
Thanks
Jack

Kyle Boatright · #6 09-09-2007, 07:09 AM

Before you even up the spinner/cowl gap, consider that the bigger gap at the bottom will make it MUCH easier to remove the bottom cowl without causing scraped paint, requiring 2 friends to help, etc.

On mine, the gap at the top is probably 3/8", but is considerably larger at the bottom and it is still a chore to remove and reinstall the bottom cowl.

cytoxin · #7 09-09-2007, 11:44 AM

Quote:

Originally Posted by Kyle Boatright

Before you even up the spinner/cowl gap, consider that the bigger gap at the bottom will make it MUCH easier to remove the bottom cowl without causing scraped paint, requiring 2 friends to help, etc.

On mine, the gap at the top is probably 3/8", but is considerably larger at the bottom and it is still a chore to remove and reinstall the bottom cowl.

this could be helpful and with a nose leg in the way even more so. the only reason i can think of not to have a three bladed prop.

USCANAM · #8 09-09-2007, 02:59 PM

Thanks again Guys.
Dana, that's a good idea about cutting and pasting the front of the cowl ring. That is one thing that I'll consider when I have both cowls in place. Should have the upper cowl fitted with the hinge maybe by tomorrow. Rear edge is fitted, now trimming the bottom edges so I can fit the front properly to the lower cowl.
Jack