Peter
How many hours/years on The Lord mounts? It is recommended to replace them around every 500h or 5 years as they soften allowing the engine to sag.
Ben
In this case, the Lord mount sagging won’t affect the clearance to the oil pipe fitting.
On the TB20, one can check for sagging mounts by comparing the upper surface of the cowling with the upper surface of the spinner. In my case, there has been no visible sag since 2002
The mounts were however changed in 2008, when the engine went for the crank swap job. I initially bought Barry mounts but decided to not use them as they seemed much less sophisticated than the Lord mounts. That might have been a stupid decision, of course. I still have the Barry mounts on the shelf, but the 8130-3 form has been lost (if anybody wants to buy them cheap).
The motorsport answer would be to remove the male/male adaptor which is NPT/JIC. It would be possible to run a die down the NPT end so that it would screw further into the oil cooler.
Steven
It always amazes me how NPT threaded parts go in by a very small amount – just maybe 3 or 4 threads. Yet these are used all through aviation.
The result is that most of the fittings waste much of their length.
Your suggestion is great, but I don’t think it would be legit. Even under the FAA owner produced parts concession, one is not allowed to make up one’s own equivalents of AN or MS parts.
It would be possible to run a die down the NPT end so that it would screw further into the oil cooler.
My tendency would be to investigate tapping the oil cooler NPT thread slightly deeper, instead of modifying the adaptor fitting. I’d imagine the original thread depth on the oil cooler would have been specified primarily to accommodate the fitting without running out of male threads. It appears that the clearance issue could be resolved within that constraint, leaving the adaptor fitting intact.
had a 50min flight today – before that I took this video
Nobbi’s lacks the extra adapter.
I would recommend you to solve it using less parts, either as I suggested, or the way it has been done at Nobbi’s. Then you don’t have this problem.
In my opinion it would be wrong to slightly relocate the oil cooler, the baffles are prone to cracking at the heavy weight of the oil cooler anyway, you don’t want to weaking that “structure” even further.
The problem with that approach is that you don’t have proper adjustment on the angle at which the hose comes off the oil cooler. The only adjustment you have is tightening or loosening the NPT tapered thread, which is a very bad way of doing it because those threads are loose until they go tight and when they go tight they go very tight very quickly – over about 1/2 a turn. Another 1/4 turn and you will split the oil cooler bushing… NPT fittings are absolutely critical on correct torque otherwise you just split things.
You may get lucky as to where it ends up in angular terms, or you may not…
This bit is difficult to explain with words, but moving the oil cooler say 4mm away from that rubber mount is not a problem. The four oil cooler mounting holes are obviously matched against four holes in the baffle. But Socata didn’t get the matching right. They placed the two vertical columns (2 holes each) too far apart. So to move the oil cooler further away one doesn’t need to modify all four holes. One needs to modify only two holes.
The problem is getting in there. It will be necessary to unscrew the two hoses and completely move the oil cooler out of the way. I never like disturbing oil or fuel hoses. Even though these two are top spec teflon, and running at about 10% of their test pressure, hoses tend to fail after being disturbed. So we will have to do that very carefully.
If Nobbi’s pic is from a GT, that is really interesting. So I looked in the IPC (I have the Feb 2006 CD, off Ebay, and it is later than anything Socata published because they stopped in 2005) and found that they changed it. Up to (roughly) S/N 1842 (which is pre-GT) you have Nobbi’s solution
and after that you have mine
The 2nd pic is dated 1999.
I can only imagine that Socata changed that for a reason, and about a year before they did the GT project. Probably because somebody managed to crack their oil cooler…
The only adjustment you have is tightening or loosening the NPT tapered thread, which is a very bad way of doing it because those threads are loose until they go tight and when they go tight they go very tight very quickly – over about 1/2 a turn. Another 1/4 turn and you will split the oil cooler bushing…
Can’t buy an NPT plug tap in the UK? Three turns and you’re done.
The drawing from the later GT shows an AN822 union 90 degree NPT/JIC (as a guess only it is AN822-08D) from LAS http://www.lasaero.com/site/products/article?id=A386EVKT this then has a straight union on the flexible hose. The problem is indexing the 90 degree union in the tapered seat in the oil cooler.
