I bought an "original" 912 Mount

6 posts in this topic

Posted (edited)

Hi guys. i am in the market for a 912 mount ever since i bought my unfinished avid Model C over a year ago.by now i have ordered two replicas of the original avid mk iv engine mount for hte rotax 912 from two independent sources (one from avidkitplanes, the ohter one is a guy in the netherlands who supposedly has a jig and offered to produce one). both orders are pending since last spring and neither of the two has delivered anything (in all fairness, they haven't billed anything either, so all is good).

Imagine my excitement, when i recently found an Ad on a german UL site, where someone offered an original, unpainted, unused 912 mount for the avid. I immediately called the seller and bought the thing. Today I got the parcel and anxiously unwrapped it.

Well that was a bit of a shock, because what i took out of that box looked as if i had tried to build an engine mount myself, an i have no clue about welding! all i have is a cheap mig welder with a low and high power setting and i use it like a hotglue gun, only hotter! to my eye, the engine mount i got looks like it was produced by a person with about the same take on welding as myself.

so those of you familiar with either welding or the build quality of the original avid parts, can you please take a look at those pictures and tell me, if against my intuition, this thing could really be trusted to hold a 100hp rotax at the front of my avid?

Screenshot from 2020-07-23 11-06-42.png

it does sit flat on the floor, so whoever built it seems to have had a jig at least for the firewall or it was welded directly ont he firewall,

Screenshot from 2020-07-23 11-07-01.png

the different bows are not all in the same plane.. they don't really form a ring. not sure if that was even intended but it sure looks a bit off like that.

Screenshot from 2020-07-23 11-07-28.png

Screenshot from 2020-07-23 11-07-40.png

that's what i mean by "hot glue only hotter" .. this is exactly what my welds look like, and i too take a grinder to it afterwards if i want to make it look pretty ;)

Screenshot from 2020-07-23 11-07-49.png

Screenshot from 2020-07-23 11-08-06.png

this pipe shows "wrinkles" from bending it.. it seems to have been bent by adding dents on the inside rather than forming it with a rolling tool.

Screenshot from 2020-07-23 11-08-14.png

on one of the two larger arcs, there is even a serous dent which looks like it happened either when clamping, hammering it in place or while bending the pipe.

Screenshot from 2020-07-23 11-08-29.png

one of the straight pieces at leas shows the letters "MIL" which seem to indicate this is some kind of military grade material

Screenshot from 2020-07-23 11-08-38.png

the bushings are all marked with probably some angle numbers, 42°, 40.5°, 41° and 38° if i interpret them correctly

Screenshot from 2020-07-23 11-08-51.png

some of them look like they had a hard time so far.. a few dents are probably from storing and shipping it around, but most of it seems to have happened in production already.

Screenshot from 2020-07-23 11-09-00.png

so many different colors and so much grinding.. with the little experience i have, this really looks like no one could guess what the material strength at this attachment point really is. i did things like that for little push-carts i have built and these where exactly the kind of joints that would crack up and break first.

Screenshot from 2020-07-23 11-09-10.png

even though everything looks like it was never used, this pipe seems to have some primer or something left on it.. so maybe it was scrapped from somewhere? or is that only a protective paint that's put on the raw stock to preserve it?

Screenshot from 2020-07-23 11-09-21.png

If i had mad this, this would be the weld i'd show everybody and brag about ;) .. it is also by far the nicest on the entire mount and accessories.

Screenshot from 2020-07-23 11-09-33.png

so please tell me what you think about this mount.. maybe i can at least use it to build a jig and then hand it over to a real welder to produce a safer replica of this..

i have to say, i have never seen any original avid parts in a raw state.. i bought my avid fully covered and painted with a rotax 582 at the front which did some ground runs 20 years ago and was then left sitting in a shed, so that one really needs to go and i want to replace it with a 912 before the maiden flight of this avid.

by the way, i've payed about 750$ for this.. compared to a new one from avidkitplanes for 1000$ this seemed like a fair offer for a 2nd hand part... not so sure about this deal anymore.

cheers

Pascal

Edited by Pascal

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Posted

I am not a pro welder by any means but I.ve never had to grind down my welds. A couple of the welds look like they don.t have proper penetration. I would have doubts that this was made by Avid.  The quality just doesn't look like it came from Avid. As far as strength goes, that's a guess at best. I, myself, would redo it. After I was sure it fit the engine and firewall.

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Posted

Definitely not a original Avid part or even a copy of the Avid mount.  I wound not trust that mount on a go kart let alone an airplane.

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Posted (edited)


Paul, are you saying that the original mount is also different in its design (like where the pipes attach to and all that)? that would mean i can't even use it as a template

EDIT: i can actually answer this question myself.. looking at the avidkitplanes engine mount it is clearly even a different shape.. the upper and lower connecting rods between the round mounting holes are straight here and bent in mine.. also the round mounts look far bigger and seem to have a different shape alltogether.

geee.. i'll try to convice the seller to take that think back.. thank you all for confirming my observations (and i'm happy to hear that this is not the quality level of the rest of the plane ;))

 

 

Screenshot from 2020-07-23 14-51-55.png

Edited by Pascal

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Posted

Grinding a weld is what you do to try to make an ugly weld look nice.  That is what I would have to do.   And that's why if it's something at all critical, I take the piece to someone who knows what they are doing, and have them weld it.  I've never seen any thing that came from Avid look like this.   JImChuk

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Posted

well i guess i should have posted this to the "dumb stunts" forum ;) i called the seller and he agreed to take it back and pay most of the money back, minus some $$ for packing it up etc. but that's allright.. i don't think he knowingly sold me chunk and after all i could have looked closer at the original picture he posted in the ad which was low res but still good enough to see the geometrical differences between his mount and the avidkitplanes one.

so after all just a dumb stunt that cost me a few bucks to learn a lesson ;) 

so in case anybody out there has a 912 mount for my avid, please let me know ;) i'm still interested!

this at least helps me to understand, how we got to the over-regulated stucture in aviation as we know it. in switzerland even experimentals are quite regulated and anything structural needs to be verfied by approved engineers and stuff before you are allowed to mount it to your plane.. for exmaple this engine mount, since i can't prove with pictures that it has the same structure as the original and since it is obvious, that it was not welded professionally would probably never make it through the final inspection before getting the permit to fly.. i'm not saying that i agree with the politics, that we need to save every idiot's live by taking away the freedom of everybody else and over complicating things, but at least now i understand, how this specific regulation probably got into existence..

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