Peter
When you move away from Metal for the construction of aircraft you also move away from things being exactly the same size, most composite aircraft have minor variations in size so much so that when you go on a Diamond type maintenance course at the factory they will talk about the selective use of bolts.
Wooden aircraft vary by the day, my Robin that has be in a very wam and dry hangar under re-build for far too long has shrunk and this can be seen by the sharp observer , I have no doubts that a few days outside in a more humid environment will return the airframe to its correct size before we fully rig it.
Once when touring Spain and having parked the aircraft in a particularly hot and dry place I returned to the aircraft to find a small amount of play in the Stabiliser fittings, the solution to this problem was to launch a bucket of water over the back of the aircraft to increase the humidity in the wooden structure, within hours the play was gone.
In these days of ultra high precision manufacturing people don’t like to talk about manufacturing variations and tolerances but the good old art of trimming parts to fit is alive and well even in the highest Tech carbon composite workshops.
Your tails of the RAF Tucano fleet ring true I was once told that in an early aircraft during maintenance the Rear ejection seat could not be removed as it fouled the side of the cockpit……….. investigation found the rear fuselage frame had been installed backwards.
As an owner of a TB20 since 2002 my view is that while the French are good engineers and tend to come up with effective engineering solutions to things, the end product is negatively affected by a massive cultural preference to buy “French made everything”. This is not to be interpreted as an attack on France, please!! Lots of other countries do the same, but most of them can’t and don’t make anything much… The problem with doing this in aviation is that the customer gets shafted on parts prices and, inevitably, availability. Airbus were very aware they could not sell their product around the world if they did that, so they use standard US parts (my A&P/IA maintains them in his day job).
The result is that the plane uses a lot of nonstandard (which in aviation means non US made) parts which, in the ultra-tight EASA Part M business, and with the average maint company naturally preferring to make a margin on the most expensive option, have to be bought from the airframe manufacturer. They are made by little outfits in sheds around the French countryside (which vanish when the old guy pops his clogs), by some bigger firms many of which have been bought by US companies and the low volume parts shut down (I found this when tracking down OEM parts – example), by really obscure firms making parts for the UL market (which the aircraft mfg buys and certifies under their 145 approval; a lot of hydraulics parts) and for some they do use standard parts (Cleveland wheels and brakes). Many of the supply chain firms don’t even have a website so finding them (and buying parts under false pretences 
) is hard.
This in turn creates a high value parts supply business. The reluctance by Socata to pass this on is what reportedly frustrated various attempts to restart the TB production by various 3rd parties; nobody is going to build a plane if they have to buy all the bits from elsewhere; the profit of a parts business comes from buying them cheap, from non aviation sources, and converting them into “aviation” parts under your oganisational approval, and selling whole planes is no good because you make the profit only once.
With a plane with a conventional engine, like a TB, you can bypass the factory for anything engine related (crafty people even bought the hoses directly, but this is possible only if you are not over the barrel of a maintenance company which prefers to make a 25% margin on €2000’s worth of hoses) so your need for airframe parts is just the, ahem, airframe, and you won’t be needing much of those unless the plane has been neglected (neglected TBs are expensive to keep going). But on a diesel Robin you are over the barrel on the engine too…
And with no FAA TC you can’t put it on the N-reg and run Part 91 maintenance which allows the use of used parts, with flexible options on the required certificates. An 8130-3 is accepted by anybody even if not actually required, and it doesn’t have to be issued by the airframe mfg.
The present-day Robin company has been described to me by owners as barely hanging in there organisationally, running a “1970s Aston Martin” type of assembly line and currently struggling to make 1 plane per week and with quite some backlog, and with no two of them being the same size (made of wood, and minimal use of jigs) if say you have to replace a door, the new one doesn’t fit until it is “trimmed”. It reminds me of the story of the RAF Tucano when it was built by Shorts Brothers in Ireland; one test pilot reported a variation in dimensions of the order of 10cm (!) on the overall length, so some of them could be recovered from a spin and some could not 
I find it very hard to think of a worse combination for the private owner that a new robin aircraft with an early Thielert engine.
To start with the engine it was unreliable in that it would throw up warnings at the drop of a hat, most of these being spurious, fortunately the Thielert engine ( or whatever it’s called this week ) has become reliable and I don’t think I have been offsite to fix a spurious fault in the last three years.
When it comes to the Robin customer support I am at a loss to understand how they can make procurement of spare parts such an administrative epic, in the these days of ordering stuff on amazon and getting it shipped overnight the attitude of Robin simply beggars belief, Robin simply must get its act out of the 1930’s if they want to be taken seriously. The only saving grace is they will make stuff for the older aircraft……….. eventually!
Personally I fly a Robin because it is such fun to fly and economic to run and I have access to stock of common parts that we need to support customer aircraft. I would not operate a Robin as a commercial aircraft because the customer support for what could be a superb club trainer is so poor that the aircraft could be grounded for weeks for the most trivial part and the paperwork required to get it.
As you might guess my Robin is powered by that famous ex- agricultural water pump engine from Lycoming……… at least I can get the parts quickly.
boscomantico wrote:
It confirms my decision to buy a new airplane, but with an old school engine. No troubles to speak of, in 14 years now.
Yes, see my post #58 (posted only three years ago, not fourteen, but same conclusion).
Check back in another three years and see if Continental is still selling Thielerts, and to whom.
Thanks Neal.
Dreadful these stories of small lamps grounding you before some specific engineer comes to the place where you happen to be.
It confirms my decision to buy a new airplane, but with an old school engine. No troubles to speak of, in 14 years now.
In fact, I would say the sweet years of an airframe are between the third and the eighth. In these years, you essentially just change the oil, and otherwise fly, fly, fly. YMMV.
NealCS wrote:
What is amazing is that they still support every Robin ever made and will manufacture whatever part you need.
I wish… We’ve been trying to get a replacement fuel sender for our DR250 for four years.
Thanks beta tester Neal, it really is an amazing summary. You normally only hear hagiographies or rants, so a balanced write up is invaluable. Our club did try the factory demonstrator in 2008, but there was no mention from the sales person about resetting the electronics or anything like this
I don’t know the exact rule of it but:
I have flown a lot DA42 in the early of their Centurion engine 2.0. We have in the plane a small laptop and the connector to delog the engine fault.
I always send it to our maintenance shop and depending on fault (usually cam sensor fault) we reset the fault ourself…
I got one time a faulty FADEC (engine stop on ECU test) that needed our guys to bring us a other FADEC
I would think that the electrical path to the starter motor is very simple – due to the heavy current involved. It is typically something like
battery → ground power relay → master relay → starter relay → starter motor
and you just need a voltmeter to trace where the problem lies.
That’s unless the Robin doesn’t use the normal key switch for starting, and the “computer” turns on the starter relay. Then one will find the source immediately by putting a voltmeter on the starter relay coil.
You are right about deep pockets, although buying new alleviates that one, by having a warranty. I think the warranty bill on mine was best part of 100k
