What proportion of the enclosed wing volume is the tank volume on a TB20?
They did contribute the data that they died.
Yes, but they might have dived straight in (etc).
What proportion of the enclosed wing volume is the tank volume on a TB20?
I would have to do some measurements of the wing but I would guess the tank is about 50% of the wing. On the TB9/10 it is much less; the tanks are shortened.
However the empty space would fill rapidly with water. There are big holes in the trailing edge e.g. for the flap/aileron linkages, landing gear, and other big holes which do nothing. I know, because I spray ACF50 in through them 
Over the years I have invested in a few things with that scenario in mind, by decreasing order of importance:
1/Maintenance
2/Recurrent training
3/IR
4/high altitude, low wing, high glide ratio, retractable gear plane
5/life raft
6/life jackets
7/signalling equipment ATTACHED TO THE LIFE JACKET (gps PLB, waterproof torch, flares)
Note that all these are as useful on land as over the sea, apart from 6/. The life raft will make a great shelter in any inhospitable terrain.
From my crossing altitude, if the engine quits I’ll have at least 15 minutes before I hit the water; but I always wear my jacket regardless – I’ll be busy during those 15min, especially with passengers on board.
Which kind of plane do you have in mind that is fast, flies high, has retractable gear, and still has a high glide ratio ? I have a Beech F33 – the glide ratio really sucks, to be honest :)
When talking about “staying afloat”, I guess all we can expect is something between 1 and 5 min. max.
Taking the TB20, empty weight 900kg, tank volume 332 litres i.e. ~330kg. And most of the 900kg is metal
Most of which is aluminium. And while most of the weight is metal, much of the volume is plastic, leather, rubber, foam, cork, pipework, etc. So it’s probably conservative to take an average specific gravity of about 2.7. Sea water is about 1.03.
The TB20’s empty weight in air is 900 kg, so assuming most of the metal is aluminium, weight in sea water is approx 900 x (1.7/2.7) = 570 kg.
Deduct the 330 kg displaced by the fuel tanks, but add, say, 70 kg of fuel, and we have a net weight in water of about 300 kg. It’s still going to sink after all but 300 litres of trapped air has escaped from the airframe – unless you inflate a spare life raft in the fuselage.
BUT WAIT… If you fit a brace of 31" bushwheels (as you should!), you’ll only need another 100-odd litres of buoyancy in your cargo hold and you’ll no longer be in command of a flying submarine.
@EuroFlyer what you are looking for is the Mooney Rocket – retractable, very fast and with a fully feathering prop it has a great glide ratio.
Would be nice ! The Mooney Rocket is a conversion by Rocket Engineering, of a K model Mooney with an engine upgrade (TCM TSIO 360 replaced by TCM TSIO 520 with 310 hp), plus the feathering option….. Quite an awesome machine, however they don’t do this conversion anymore, as far as I know. There is another model, the Mooney Missile, where the feathering also was part of the conversion (in this case a Model J).
I’ll have a look into the feathering option in the Beech; I have a TCM IO 520 perhaps its somehow possible.
They don’t but they still support it.
Peter wrote:
Yes, but they might have dived straight in (etc).
There’s usually some evidence what happened: for instance, there’s been evidence left that an egress was successful but the occupants succumbed, or there has been evidence of a high speed impact with water (prior ATC communications, weather conditions vs pilot rating/aircraft equipment, fragmented wreckage floating/washed up, for example last year’s Rockwell Commander near Blackpool). Not all unfortunate aircraft/water interfaces leave zero traces.
EuroFlyer wrote:
Which kind of plane do you have in mind that is fast, flies high, has retractable gear, and still has a high glide ratio ?
The PA46 isn’t bad at all. Book says 2.4nm/1000feet. I assume 2nm/1000feet when estimating how long I’ll be out of range. I have never tried shutting down the engine in flight to experience what it’s actually like, but there are quite a few examples of successful dead sticks landings to an airport.
