Tight fit Aerovee motor mount

[Darick]

I searched but couldn't find posts on the motor mount not fitting easily into the fuselage mounts. The bottom motor mount outside dimension is 33". The fuselage distance is SLIGHTLY LESS than 33", (the mount must fit inside the fuselage brackets). It seems the round landing gear receivers, which extend about 1/4" past the square part of the mount, needs to be filed off so they will fit better into the generous radius of the fuselage mounting angles. I'm not sure at this point if this will totally solve the problem but it will help.

I can't see how I could have made the width (33") too short since this distance has been determined by the prepunched holes in the bottom skin.

Help with any suggestions please?
Darick

[peter anson]

Hi Darick, I think there are two problems fitting the engine mount: The first is caused by the taper of both the fuselage and the mount. You might find that it's just a matter of getting everything in the right position and it will just slip in. I helped a friend recently with a Xenos and we had exactly the same problem. The mount couldn't possibly fit and suddenly it was in. At worst you might have to do a little bevel on the aluminium (that's aluminum) fitting but I think you will find that it fits if bring the mount in from above and angled forward slightly.

The other problem is more serious and takes more drastic fixing. The lower extension of the steel tube that the gear leg fits into interferes with the lower fuselage fitting. I think Sonex should have fixed this one up years ago. I had to carve a large amount out of both the lower fuselage fittings which seriously reduces the lateral strength of the fitting. My friend with the Xenos had to do the same with his and when I visited another builder I asked him if he had done the same. He said no, but I think he had just forgotten doing it because the fitting was obviously modified. I'll send you a photo.

I'd like to hear any other views on this.

Peter
Sonex 894

[Bryan Cotton]

Ah yes- the old tight motor mount. Page 37 on my thread down towards the bottom:
viewtopic.php?f=39&t=578&p=11749&hilit=+motor+mount+#p11749
Mainly don't panic that it is tight and yes you have to hack up those angles to clear the gear leg sockets if you are building a taildragger.

[Darick]

Thanks Bryan and Peter for photos and info. I'll be working on getting the motor mount installed today.

[Bryan Cotton]

One thing I would do differently- before you install the gear either dent the firewall so you can get the nut on and off and have clearance, or make holes/covers that line up with the bolts.