Travelling, in the european context, = international flying. Therefore, I was not referring to intra-UK flights (where, admittedly, the situation is more unique, with the possibility to fly IFR cross country at 1000 feet AGL).
In Germany, my estimate is that 90% of the normally aspirated aircraft with 200 hp or less are not IFR approved. On the other hand, 80% of all aircraft with 230hp or more (or those with a turbocharger) are IFR approved. There are reasons for this demarcation line.
Another point is range, which is very important for travelling machines. Let me list those european countries which don't have a regular network of Avgas refuelling points: Italy, Greece, Bosnia, Macedonia, Romania, Bulgaria, Turkey, Ukraine and all the baltic states. That effectively is half of Europe. Then, you can add northern Africa to the list. Even in western Europe, several big airports don't have Avgas any more. Being able to "skip" a refuel is great value.
Well, in the end it probably really boils down to the definition of "travelling" vs. "adventure touring".
The UK is a very different case because most enroute CAS is Class A (TMAs and airways basically) which cannot be penetrated under VFR, and due to the strict demarcation in ATC services it is virtually impossible to get a pop-up IFR clearance into it under any circumstances (other than possibly an emergency). The only way to get into it is to file a full Eurocontrol flight plan, and even then if you file the level too low (the rules for this are confidential but say FL060 or lower) the IFR control service (London Control or Manchester Control) will dump it even before you departed. So this cannot be done in an ad-hoc manner.
So the UK has a big culture of flying in the Class G below, for which the IMC Rating can be used, and this is very handy because in Class G you can change VFR-IFR anytime, no radio required, etc.
It's a great system which has stood the test of time since 1969 and is very safe. The rest of Europe cringes at the thought of flying in cloud without radar but there has never been a midair collision when doing this. And you can usually get radar cover from one of the LARS units if you really want it.
The problem is that one often spends a lot of time in cloud, because the clouds always seem to know where the Class A base is and they grow just a few hundred ft into it 
Flying on the full IR is totally different in that one climbs up and sits there in VMC.
In Germany, my estimate is that 90% of the normally aspirated aircraft with 200 hp or less are not IFR approved
However, isn't that simply a result of the German "IFR Certificate" maintenance company fundraising scheme? People flying the lower powered stuff don't bother paying the extra money, and if they don't have an IR it would be a waste of money anyway. I know this is required only for the D-regs but they probably form the vast majority of the "not regular IFR" fleet. I would bet that anybody in Germany with the will/money to get the full IR will then buy only a capable IFR machine - what would be the point otherwise?
Just about every "normal" (non aerobatic, non special purpose) plane with an ICAO CofA leaves the factory approved for IFR and you just need to make sure it carries the avionics as required by the owner of the airspace you want to fly IFR in. For example a new SR22 has always been illegal for IFR in the UK (in CAS) because it had no ADF and no DME, yet nobody would say an SR22 is not IFR approved. Every PA28, every Cessna, etc, are IFR approved from the factory.
Incidentally how did a D-reg SR22 without a DME get the IFR Certificate?
Another point is range
That is really vital. Most PA28 types have a zero fuel range of about 600nm which is OK for flights up to say 300nm. The better IFR tourers have a range over 1000nm (TB20 is ~1300nm) and this makes them far more practical. Especially if one has a fuel totaliser so one really knows the fuel situation.
1300 NM range at what powersetting? I always thought/read the TB20 has a range of 900-1000 NM. No?
Well, non radar flying in IMC is something to get used to. The fact that there has never been a midair does not necessarily mean that it will not happen... I do see the advantages, but there is an obvious risk too.
TAS at FL100-120 is about 140kt and the fuel flow is just below 9 USG/hr. That's straight peak EGT, wide open throttle. 2200rpm. Lower RPM helps - see here.
I have often seen the range showing as 1300nm after the top of climb, in no wind conditions.
Yes, the POH says something different, but the way Socata worked out their "best economy" and "best power" tables remains a mystery.
Can it be flown lean of peak? Next time I fly i'll check what my range would be at 140 ktas. I have 7 gallons less fuel though ;-)
Can it be flown lean of peak?
Yes but careful measurements suggest there is almost no MPG gain.
Most of the "LOP gain" comes from flying slower
My engine doesn't run very smooth when significantly LOP so I don't bother.
The main reason why i fly LOP is because for the Conti (have no idea about Lyc!) the engine will last longer, mainly (but not only) because the temperartures are lower. At least this is the standard point of view among a couple of thousand Cirrus Pilots at COPA at the moment.
But the efficiency is cool too: 170 KTAS at FL110 with 12-12.3 GPH
Thank you for the replies and good to see simple FG SEP being used for IMC. My thesis is that these aircraft with a $300~350k new price point have such a statistically significant safety advantage record (two to three times safer than retractable gear aircraft, heavier complex FG SEP and an even higher factor for MEP), that it is difficult to see a volume re introduction of retractable gear aircraft in the industry.
In effect Darwin has led to a segmentation with FG SEP like these having a less than 0.5/100,000 hour fatality rate and providing OK dispatch for 300~350nm missions. The next segment is populated by a rapidly dwindling population of experienced middle aged pilots flying older legacy more capable aircraft. Note the next price point for new aircraft is two or three times higher ($600k+) than the taper wing Warrior and 172S, with a more than doubling in the accident rate.
The kinetic energy of an accident in a more capable aircraft, combined with the benign flying characteristics (the taper wing Warrior perhaps has never had a loss of control stall/spin fatality) of the simpler FG SEP, suggests that these safety advantages are built in.
In effect the future outside Kitplanes/LSA is likely to be simple FG SEP for 300~350nm average missions, and multi crew commercial turbine for the rest. The Cirrus being the only volume contender that might provide medium range IFR capability.
A re-engined, updated Turbo Dakota (200HP turbo) or similar 172S might be an interesting development if they could be introduced at $400K, but this is unlikely.
The next segment is populated by a rapidly dwindling population of experienced middle aged pilots flying older legacy more capable aircraft
That's a good analysis (the comment makes me smile ) but I think it is specific to Europe, where a capable plane is a chocolate teapot unless you have an IR, but the private pilot IR process has been thoroughly shafted by regulation and FTO revenue creation.
In UK airspace, you have the IMCR but you don't need a 150kt FL200 IFR plane to use that, given that you spend much of your time cloud hole drilling at 2400ft/3400ft/etc. You can do it with anything that is stable, preferably has an autopilot, and with ILS and a decent GPS which can be a handheld because there is no BRNAV etc equipment carriage requirement.
But in the USA, Cirrus for example sold best part of 10k planes. I am sure many of them fly only VFR (which is viable in the USA, due to the 18k Class A base) but that sales figure could have never happened in Europe where an SR22 is poor value without an IR. And not all US based SR22 pilots are in their 50s or older. Many are a lot younger.
So I think it is mainly Europe's screwing over of IR holders that has driven more capable GA here into the ground. Of course there are other factors like a lack of airports...
So I think it is mainly Europe's screwing over of IR holders that has driven more capable GA here into the ground
Absolutely.
