My TR182 is undergoing an extensive annual and some things were found that will require parts with a lead time. Given that I was completely devastated about this, the shop owner offered me a TB10 free of charge as my ride for the next 10 days. I've never flown a Socata before and given that this is the official TB20 forum in all-GA disguise, I was curious 
The TB10 is like the TB20 but with a fixed gear and a 180hp Lycoming O-360 with a 2-blade constant speed prop. The aircraft is rather old (serial #178) and with simple equipment but in overall good condition.
In order to be legal, the shop owner did 3 patterns with me. It was a pleasure to fly. The controls are very well balanced and it almost flies by itself. Takeoff roll is very long compared to a C172 with only 150hp but the climb rate is rather good. Stall is absolutely benign, no tendency to do anything nasty, just wants to take its nose down and fly. Steep turns are remarkably easy, much easier than in a C182 which doesn't really like doing them. To the TB10 they were natural. Landing is easier than with any other airplane I've flown so far. Once the flaps are retracted, it wants to fly 70 knots, not slower, not faster and it flares nicely and keeps complete aileron control until touchdown. I've never experienced that before. However, after touchdown it takes the nose down rather quickly with a noticeable impact. That seems to be the way it does it but felt a bit awkward.
The cabin is very comfortable in the front row. It looks and feels like a 1970s Renault. The back row is not very good, better for luggage than for adult passengers. The cabin is significantly smaller than a C182. Even though the gullwing doors are 100x better than the suicide Piper/Mooney single door design, it becomes a sauna on hot days on the ground. The small left side window opens in a weird way and is very much in the way. I suppose that TB-pros taxi with open doors and just close them when lining up? At least one doesn't have to trust the co-pilot to hold/lock the door which can be a clueless spouse...
What surprised me about the TB10 is the fuel flow in relation to speed. The airplane does around 110kt but the O-360 consumes ca. 36l/h 100LL. That is not good. My C172M with a O-320 flies 105kt with 28l/h Mogas (1.88€/l vs 2.56€/l here).
What I also noticed is that it easily gets out of balance when weight is not distributed well. I made the mistake of starting on the right tank and being the only person on bord, I then had to apply constant aileron to the right to correct for the imbalance. I assume this can be fixed by always starting on the left tank when alone.
So while I think it is an extremely well balanced and comfortable aircraft which I enjoy flying very much, its speed does not justify the high fuel consumption. I wonder why it is so slow/thirsty?
Try throttling back a bit so you're going the speed your C172 goes. Given that form drag increases at the square of airspeed, if you slow to 105 knots you need to spend about 10% less power on overcoming form drag. Still might use more fuel than the C172 but it'll certainly make a noticeable improvement in fuel burn.
this is the official TB20 forum in all-GA disguise
However, after touchdown it takes the nose down rather quickly with a noticeable impact. That seems to be the way it does it but felt a bit awkward.
I find I have to hold it back quite actively to stop it just popping the nosewheel down ASAP. But the TB20 might be more nose-heavy than the TB10, maybe?
I suppose that TB-pros taxi with open doors and just close them when lining up?
On very hot days, it is OK to open the door and stick one's hand into the gap in a way which holds the door in (one's fingers on the outside of the door edge) so it can't fly open (hard to explain). You don't want the door to fly open in say a 30kt crosswind, because it is likely to do some damage.
What surprised me about the TB10 is the fuel flow in relation to speed. The airplane does around 110kt but the O-360 consumes ca. 36l/h 100LL. That is not good
Was it at peak EGT, etc?
What I also noticed is that it easily gets out of balance when weight is not distributed well. I made the mistake of starting on the right tank and being the only person on bord, I then had to apply constant aileron to the right to correct for the imbalance.
I thought all planes did that. When flying alone, I always run down the left tank, by about 10mm on the gauge. Otherwise, if you rudder trim so the ball is in the middle, you are flying "sideways". A plane must be balanced in roll, to start with, otherwise nothing will be right.
I assume this can be fixed by always starting on the left tank when alone.
Yes. Actually, start on the RH tank, then before the power checks (at the runway holding point) switch to the LH tank (the usual TB procedure) so the flight commences on the LH tank.
I wonder why it is so slow/thirsty?
I can't comment on the figures (I really don't know whether it should be 110 or 120 etc) but would say that if you really care (which for the short time you probably don't) do the usual checks on the gauges. The analog fuel flow gauge is PROB99 +/-10% at best (i.e. crap), the RPM gauge is very sensitive in that power is the third power of the RPM, the ASI might be way out... Even if it has a fuel totaliser the chance is that it is way off because most pilots who I know have one don't use it for anything serious.
Try throttling back a bit so you're going the speed your C172 goes. Given that form drag increases at the square of airspeed, if you slow to 105 knots you need to spend about 10% less power on overcoming form drag. Still might use more fuel than the C172 but it'll certainly make a noticeable improvement in fuel burn.
Well, my C172 does 105kt with 28/l and my TR182 does 156kt with 45l/h with much higher payload and cabin size. That doesn't compare favorably for the TB10. The TB20 however is one of the most efficient travellers. I am just surprised that the TB10 is so poor in fuel consumption/speed.
Was it at peak EGT, etc?
No, I always fly full rich, my instructor told me the red lever is just used to turn off the engine... of course it was, my TB10 has an EGT It does not have a fuel flow meter or totalizer so the consumption was taken from the POH and by asking the owner. I have not verified this numbers at the pump station yet. 110kt is what it is supposed to fly which I find to be rather low given that the fuselage looks rather streamlined compared to a C172.
Initially the TB10 appeared to me like a French PA28 clone. After having it flown for 2h, I think it is far better than the PA28.
start on the RH tank, then before the power checks (at the runway holding point) switch to the LH tank (the usual TB procedure) so the flight commences on the LH tank.
Peter
I always take off with the tank I've used to start, taxi etc. If there is any air in the line it can take a surprising amount of time to work its way through. A friend had a bad experience in Alderney with that, fortunately he was quick with the tank swap and fuel pump - plus having the height of the cliffs to glide down from!
Ted
my TR182 does 156kt with 45l/h
TAS or IAS? What altitude?
I always take off with the tank I've used to start, taxi etc. If there is any air in the line it can take a surprising amount of time to work its way through. A friend had a bad experience in Alderney with that, fortunately he was quick with the tank swap and fuel pump - plus having the height of the cliffs to glide down from!
I see your point Ted, but it isn't the TB20 POH procedure.
Also it seems that this is a tradeoff between the opportunity of discovering a fuel system blockage before departure against discovering it enroute and then hoping that you are high enough to get the engine restarted before you hit the ground.
I think the absolutely crucial thing is to do the power checks after the final tank switch. Otherwise, if the newly selected fuel path is blocked, there is a good chance of getting airborne with it.....
On some types e.g. some PA28s, people have managed to shut off the fuel completely and still get airborne. I don't think this is possible with a fuel injected system because there is no fuel reservoir (in the RSA-5AD1 fuel servo, for sure) as there is in a carburretor.
The TB10 has a carb and maybe its POH says something different.
TAS or IAS? What altitude?
TAS of course, IAS is a totally meaningless number other than Vs0/Vx/Vy etc. referring to it. I have both an air data computer (Aspen) and an accurate fuel flow meter (EDM 830). It is around FL150, my normal cruise altitude. Of course the TB10 was operated down low, ca. 5000ft but it is more similar to the C172 in performance and load carrying ability so I was expecting similar fuel flow.
The C172M always consumes around 28l/h (measured with the fuel pump) and 29l/h when going over the Alps (because the climb to 11000ft takes very long). It is quite an efficient aircraft with excellent cooling (read: terrible drag) so it can be leaned very early on (when full throttle equals to less than 75% BHP).
BTW: why do low wing aircraft never have a fuel cross feed? I think the PA28/TB10/TB20/Cirrus way of having to switch tanks is very stupid and unnecessarily dangerous. Last year a PA28 landed short of our airfield because the pilot didn't execute the checklist and was on a drained tank. In the PA28, the fuel selector is extremely well hidden (down low next to the rudder pedals) and in the TB10 it's hidden behind the yoke. It doesn't help that the French think weird pictograms next to switches are better than English words. Only the Cirrus placed it well, on the middle console next to the fuel gauges.
I can't see a technical reason for not having the cross feed. My TR182 has 7h of endurance and I never put the selector on any position but BOTH and know that I can fly for 7h without having to remember anything.
However, after touchdown it takes the nose down rather quickly with a noticeable impact. That seems to be the way it does it but felt a bit awkward.
I find I have to hold it back quite actively to stop it just popping the nosewheel down ASAP. But the TB20 might be more nose-heavy than the TB10, maybe?
Same in the -10 - will full flaps you need to smartly pull back almost to the stops to stop the nose dropping.
What surprised me about the TB10 is the fuel flow in relation to speed. The airplane does around 110kt but the O-360 consumes ca. 36l/h 100LL. That is not good. My C172M with a O-320 flies 105kt with 28l/h Mogas (1.88€/l vs 2.56€/l here).
Properly leaned I get about 125KTAS at 36lph. At 28lph I get 107KTAS, give or take. Balance can make a 4 or 5 knot difference between the front and the back limits - these aircraft really like being flown tail heavy. Getting the roll balance right also adds about 2KTAS.
