Plastic Seat Tanks

[gyroo]

Thanks for your offer Nick - I"ll bear that in mind!For the moment I"m using photos and diagrams from all over the Web, modified if required in MGI Photosuite (an old but extremely simple jpeg editing program).Cheers,Mark

[tonydenton]

can some one pm Gerry"s phone number to me so that I can contact him on please.

[RossM]

Try some experiment with your old seat tank Nick.Cut the top off it, cut a hole for the drain,

[gyroo]

Howdy Ross,Novel idea. From all the Web hunting and research I"ve done on fuel system safety, it seems pretty clear that fuel tanks or fuel cells with internal bladders are definitely the way to go. Certainly, for a fuel tank to withstand the FAA 50 foot drop test, it has to have a stout bladder inside.Most "racing fuel cells" have a steel or aluminium outer shell, then an internal bladder. The internal bladder is usually filled with foam to prevent the bladder from collapsing like a collapsed lung, and which also acts as an anti-sloshing measure. A different design of fuel cell is one with an outer metal shell, then a spun cross-linked polyethylene internal tank. The polyethylene inner shell is self-supporting, and inside that tank foam blocks for anti-sloshing are placed into the lower 1/3 to 1/2 usually kept in position by a baffle, sheet or web.These fuel cells are all well and good for 4 strokes, but not so good for 2 strokes. Theoretically you shouldn"t use foam in a 2 stroke tank because the fuel won"t necessarily quickly mix thoroughly if 2 stroke oil is tipped in directly during refueling (as in, like, a 2-stroke bike"s teardrop tank being filled at a servo). This would only be a concern if, for instance, the oil was tipped in then the fuel tipped in then the gyro started and immediately flown. Of course, you should opt to scrupulously premix your 2-stroke fuel before tipping it into the main tank). Cheers,Mark R

[birdy]

Sloshing???, in a rotorcraft that should never go negative?If your fuel isnt pinned to the bottom of the tank by gravity, air in fuel is not your greatest consern.

[gyroo]

hah hah -I thought I"d get a nip or two about tipping the oil in then putting the fuel in!The only time I do that is on a completely empty tank, and where I know exactly how many litres of gasoline are going in immediately following the oil. The most usual scenario here is when you"re at the last servo with 98 octane gas before arriving at your flying field. Rather than line up 2 or 3 jerry cans it"s easier to just fill the gyro tank direct. Mixing is really thorough as the gasoline cascades in picking and swirling up the oil, and final mixing occurs during the drive to the flying site. I have on occasions also done a thorough pre-mix in small 5 litre fuel cans, then tipped the very red oil-rich gasoline mix into the gyro tank immediately before the gasoline goes in. Obviously the whole process become trickier when you"re dealing with a part-filled tank and you need to work out precise fractions and percentages in relation to how much oil goes in.Otherwise, my usual method is to line up whatever number of jerry cans I think I"ll consume and to do the pre-mix in the jerry cans with X amount of oil going in to each before the 20 litres of gasoline goes in immediately after. I then obviously bounce and slosh the jerry cans a bit around to ensure complete mixing.And - yeah, Birdy - I thought you"d wake up and bite about sloshing! I dunno why the race car world is so concerned with sloshing, but anti-slosh baffles are mandatory in most racing codes for some reason. Also, the FAA requires baffles in tanks after they get to a certain volume, but I think that"s more to do with having those baffles there to keep the sides from bowing out.Mark R

[GraemeMonro]

I have seen one bloke fly pretty well sloshed.

[WEST OZ FLYER]

And - yeah, Birdy - I thought you"d wake up and bite about sloshing! I dunno why the race car world is so concerned with sloshing, but anti-slosh baffles are mandatory in most racing codes for some reason. Also, the FAA requires baffles in tanks after they get to a certain volume, but I think that"s more to do with having those baffles there to keep the sides from bowing out.Mark R Nope, the foam actually is there to prevent vapour concentration. More importantly prevents the vapours mixing with air reducing the explosion risk. The baffles are for "strength" in the tank. In the event of on accident you have smaller quantities of fuel contained in smaller area thus limiting the forces causing stress and cracking of a large quantity in a large area. A bit like trying to swing 4 small hammers or one sledge hammer of equal weight and force. The 4 smaller hammers with a smaller arc may dent what you are hitting but the sledgehammer will smash as it has time and space to build it"s energy.

[Des Garvin]

"I have seen one bloke fly pretty well sloshed" Yeh he was a little bloke (about Graeme"s build) and he had a very well built partner and she got disgusted with him always coming home sloshed, so he flew when she threw him out aye Mr Munro?

[MadMuz]

Sloshing doesn"t mean that there is any negative involved, the fuel can go from one side to the other and back again from rudder movements even at straight and level..... or a

[birdy]

Theres a big difference between a ground bound fuel load and one ina aircraft.Hangn a drift in a car means the fuel will be pinned to the side of the tank thats on the outside of the drift. The airborn fuel dose the same ina 90* bank, but the tank is at the same angle, so the fuel is still pinned to the bottom.And if you have an air suc issue with little things like wen you blast off, chop the throttle, flop the foot rests, then youd better reroot your fuel systm so,s its like a proper aircraft.

[WEST OZ FLYER]

The airborn fuel dose the same ina 90* bank, but the tank is at the same angle, so the fuel is still pinned to the bottom.If this was not true your automotive engine in your aircraft would make some horrible noises mid corner.

[birdy]

yes, sum folks just dont understand the blood chilln effect silence can have, ina aircraft.

[t-bird]

Hi MarkYou have said that your aspiration is that fuel tanks should be drop tested to 50 feet as per FAR 27.952 and have fuel bladders in.My question is why ?If you sit on a fuel tank then surely the pilot will also need to be drop tested, I for one will not survive a 15 meter fall.You are also advocating separate non seat type tanks. Millions of motorcycle riders sit on fuel tanks with their crown jewels.I think that most accident impacts in a motorcycle will be higher than in a gyro. Does your car or motorcycle have a fuel bladder ? Fuel bladders add additional weight to the gyro and reduce the fuel capacity.Cars also burn in accidents but they don’t require fuel bladders etc.The reason cars and motorcycles don’t require fuel bladders even if they burn in accidents is that it is not a common occurrence and would have been fatal even if they didn’t burn.And remember that cars and motorcycles in other countries like Germany are traveling over 200 km/h on the autobahn without bladders in their fuel tanks.All I ask is for some perspective before overregulating and killing the sport.

[WEST OZ FLYER]

If you want to see the consistency of rotomoulding, have a look through the neck on your plastic jerry can ( preferably without fuel or vapours in the container