Cowling and spinner interference

[inflight]

I assume this is due to the new engine mount bushings. I don't recall where it was when I first bought the plane and I have had all the cowling off since then. Any ideas on a fix? I haven't run the motor yet since replacing the bushings so maybe it will "settle in" a little. Also, why do my pictures all come up sideways and how do I fix that? Thanks.

[jiott]

The simplest fix would be to install washers under the bolt heads where the engine mount attaches to the firewall. The shim washers under the top bolts would tip the whole engine assembly down and forward, which is what you want to line up with your cowl. The down side of this, of course, is that you will have changed the whole thrust line of the engine, which will affect the flight characteristics to some extent. How much I don't know. Maybe you will get lucky and it won't require enough shimming to matter much.

The other fix is a more laborious rework of the cowl where it attaches to the firewall to pull it up and back.

A longer prop spacer would get you clearance, but the lineup with the cowl would still be ugly.

[rosslr]

HI Mark,

I am no expert but something doesn't seem right here to me! I mean the cowls would have fit ok originally when the engine was first fitted and the bushings were new would they not? Others more knowledgeable might be able to suggest possible reasons but the only thing I can think of is that the original bushing may have been different to ones you have used????? I guess I would just want to understand why the new bushings have raised the engine to the point of interfering with the cowl rather than restoring it an even distance all round? Does the old owner have some pics of the gap you can compare?

I am sure you will get some good advice here but looks like you are making good progress with your overhaul - wont be long now!

cheers

ross

[jiott]

Good call Ross. That is hard to explain. Some investigation is in order.

[inflight]

The motor and mount came from another airplane originally and had around 100 hours before being installed on this plane. That is why I was thinking there may have been a bit of sag before the cowling was originally fitted for this airplane.

[Dave S]

Mark,

When you got the plane originally....was the cowl in place and correctly aligned?

Reflecting off Ross's comments...if cowl/spinner was correct originally, a person would think it should be the same with new bushings.

I see you have one photo of the ring mount, firewall mount and the bushings that were in place from your 7/12/2016 post.....in comparing that photo to the current asssembly of the mount - can you observe any differences in front/back offset between the top and bottom rubber bushings? The rubber bushings from the 7/12/2016 photo appear to centered correctly??

I am sure you will figure this out...and it is an interesting predicament.

[inflight]

I have definitely learned that you can't have too many photos. You would think I would know that already. Here is a shot from before the cowl ever came off the first day we saw it.

It looks like it may have had some clearance issues from the beginning but it is hard to tell from this photo. You can see some of the darker blue from the spinner on the cowl. But that may suggest some separation and only an occasional contact. I wish I had a better shot.

[Mcslamma]

A simpler fix might be, after considering all the other ideas mentioned here and ensuring no deficiencies were present, would be to lose that spinner alltogether and install an IVO skullcap spinner that allows for quick access to prop mount bolts and inspection of tape etc.. and does not get anywhere near the cowl,

My model IV had a large spinner same as yours when I obtained the airplane, but I replaced it with the skullcap when I changed the original prop with IVO IFA, and I have come to really like the look of it, as it reminds me of the front of a DHC Beaver every time I look at it.

From your pic it looks like you have an IVO prop as well..

Good luck in your efforts...

[Av8r_Sed]

I second Craig's comment here. I cracked a blade at the root on my IVO medium due to the fiberglass backplate on the UHS spinner. The problem occurred because the fiberglass compresses after torquing the prop bolts and the blades then loosened. Removing and replacing all the spinner screws in order to follow the IVO torquing schedule is also a pain.

[Esser]

I have a the 914 FWF manual if you need any info off of it. I'll be home tomorrow aft so I can dig it up for you. But Beyond torque values, I'm not sure how much help it will be for you.