Van's Air Force
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Naive question about fuel tanks
- Thread starter awilson
- Start date
Correct. The plumbing is much simpler if the tank is in the fuselage.
I don't know if that is a good idea or not but I do know that when this is done, builder put baffling in them otherwise when they are half full they slosh back and forth when banking. That is a long way to slosh and the weight and momentum can make you over roll. That's what they say anyway.
Wing tanks full of fuel will also impose extra inertia loads on the wing structure, which will reduce the safety margin and possibly overstress some of the parts that you may be relying on to stay airborne.
N42AH
Well Known Member
Portable Tank
John,
Where did you find this tank and fittings?
Why not just add one of these! Plus its removable!
John,
Where did you find this tank and fittings?
David Paule
Well Known Member
Those marine tanks leak in negative gs, at least the two in my sailboat do. Since I remove them to take them to a gas station, and the gas sloshes around, it's a bit awkward. This happens even with the vents closed.
I see that yours are rigged to vent overboard, a very good thing.
Other than that, it's a neat solution. Removable, portable, inexpensive.
I see that yours are rigged to vent overboard, a very good thing.
Other than that, it's a neat solution. Removable, portable, inexpensive.
Jetguy
Well Known Member
Where indeed!
The Theory and the basic concept is easy, its finding the hardware locally to make it all come together, that's hard.
I suggest you visit your local Aviation Bass Pro shop or Aero Cabelas. They have some great stuff for Airplanes.
http://www.basspro.com/Moeller-Mari...Portable-Fuel-Tanks/product/10205455/-1339432
The Theory and the basic concept is easy, its finding the hardware locally to make it all come together, that's hard.
I suggest you visit your local Aviation Bass Pro shop or Aero Cabelas. They have some great stuff for Airplanes.
http://www.basspro.com/Moeller-Mari...Portable-Fuel-Tanks/product/10205455/-1339432
flytoboat
Well Known Member
If you keep the ball centered, the tanks don't know (or care) if they are banked or not...
RDOG
Well Known Member
It's not all about range
It's not all about range. It's about premium mogas. The tank allows us to fly out for two hours and back for two hours and not worry about fuel. Yes we can use 100ll but we want to keep the lead out of the engine and gearbox. $3.00 mogas is better than $4.50 100ll. I know it is not much but it adds up in the long run. We also save in that we can do 50 hour oil changes by running mogas whereas if we run 100ll a lot we must do 25 hr oil changes. I can't believe I am going to say this but, we are trying to operate this wonderful airplane green. How's that for ya. The RV12 is a green vehicle if you run mogas. Remember the tank comes out in about 30 seconds. If you don't need it don't take it. I do love having the option. Have some fun out there.
Colin
It's not all about range. It's about premium mogas. The tank allows us to fly out for two hours and back for two hours and not worry about fuel. Yes we can use 100ll but we want to keep the lead out of the engine and gearbox. $3.00 mogas is better than $4.50 100ll. I know it is not much but it adds up in the long run. We also save in that we can do 50 hour oil changes by running mogas whereas if we run 100ll a lot we must do 25 hr oil changes. I can't believe I am going to say this but, we are trying to operate this wonderful airplane green. How's that for ya. The RV12 is a green vehicle if you run mogas. Remember the tank comes out in about 30 seconds. If you don't need it don't take it. I do love having the option. Have some fun out there.
Colin
MacPara
Well Known Member
Darn! I can't find the 'Like' button for this post ...
They mix - no problem, but -
You likely will not know the difference in how it runs. ROTAX has approved 100 hour oil changes if only Mogas. 25 if 100LL. Really increases cost and labor to do. Also the inside of the engine does not like 100LL. Better to avoid it if possible. If you want to go on a long CC, then you may have fewer choices. If you carry an empty 5 - 6 gal gas can, you can often go to a local station and get Mogas. More hassle, but depends.
John Bender
You likely will not know the difference in how it runs. ROTAX has approved 100 hour oil changes if only Mogas. 25 if 100LL. Really increases cost and labor to do. Also the inside of the engine does not like 100LL. Better to avoid it if possible. If you want to go on a long CC, then you may have fewer choices. If you carry an empty 5 - 6 gal gas can, you can often go to a local station and get Mogas. More hassle, but depends.
John Bender
MartySantic
Well Known Member
From a .pdf file on the ROAN website. www.rotax-owner.com
Avgas and Autogas Mixing
For the Rotax 912/914 series engines Avgas and Autogas can be mixed together in any ratio; this is done primarily to increase the octane rating of Autogas.
Method:
-100LL has a minimum motor octane of 104
-Regular automotive gasoline (87 AKI) has a minimum MON (motor octane
number) of 82.5 You can get a fairly close guess of the octane number by multiplying the MON by the percentage of that fuel in the mixture.
EXAMPLE 1:
50% 100LL and 50% Regular
(104 x .5) + (82.5 x .5) = 93.25 MON (rough approximation)
EXAMPLE 2:
75% Regular with 25% 100LL
(104 x .25) + (82.5 x .75) = 87.8
The fuel retailer will be able to supply the MON number of the fuel you are
purchasing.
Avgas and Autogas Mixing
For the Rotax 912/914 series engines Avgas and Autogas can be mixed together in any ratio; this is done primarily to increase the octane rating of Autogas.
Method:
-100LL has a minimum motor octane of 104
-Regular automotive gasoline (87 AKI) has a minimum MON (motor octane
number) of 82.5 You can get a fairly close guess of the octane number by multiplying the MON by the percentage of that fuel in the mixture.
EXAMPLE 1:
50% 100LL and 50% Regular
(104 x .5) + (82.5 x .5) = 93.25 MON (rough approximation)
EXAMPLE 2:
75% Regular with 25% 100LL
(104 x .25) + (82.5 x .75) = 87.8
The fuel retailer will be able to supply the MON number of the fuel you are
purchasing.
engineerofsorts
Well Known Member
Which tank size?
John, Colin--which size of tank did you use--the 3 or 6 gallon?
John, Colin--which size of tank did you use--the 3 or 6 gallon?
With the 912S it's 50hr oil/filter changes when running in excess of 30% 100LL and 100hrs if running less than 30% 100LL. There are some other changes such as binning the spark plugs at 100hrs rather than 200hrs and an earlier gear box internal inspection.
It all mixes with no problem.
At work we are the UK dealers for the Tecnam range of aircraft - including the IFR certified P2006T with twin Rotax 912S. 135KIAS on 38LPH total fuel burn (and yes it does climb on one engine). The aircraft is certified for Mogas up to 10% alcohol.
At the moment we are running nearly totally 100LL but hopefully will soon have some unleaded, alcohol free 95 Octane Avgas to trial.
It all mixes with no problem.
At work we are the UK dealers for the Tecnam range of aircraft - including the IFR certified P2006T with twin Rotax 912S. 135KIAS on 38LPH total fuel burn (and yes it does climb on one engine). The aircraft is certified for Mogas up to 10% alcohol.
At the moment we are running nearly totally 100LL but hopefully will soon have some unleaded, alcohol free 95 Octane Avgas to trial.
RDOG
Well Known Member
True but in this case you would have to be perfectly balanced otherwise it will move. I still think it should be considered or is worth further investigation to be sure.
RDOG
Well Known Member
full until it is empty
With the tank in the picture it is full until it is empty. The tank is pumped into the main tank when the main tank is at about 10 gallons. When we hit 10 gallons we switch on the transfer pump for about 10 min. all the fuel goes into the 20 gal tank and we confirm transfer by watching the float gage go to 16 gallons. Then add 6 gallons to the totalizer and press on with current info. The aux tank is empty so no sloshing. It works really well and remember this tank is removable so it can be used as a gas can at an out airport. Take it with you in the airport car get 6 gal at a local gas station an in about 2 min it can be reinstalled in the airplane or just transfer it into the main and do it again until the airplane is full. This system works quite well and we don't have to use 100LL.
Colin
With the tank in the picture it is full until it is empty. The tank is pumped into the main tank when the main tank is at about 10 gallons. When we hit 10 gallons we switch on the transfer pump for about 10 min. all the fuel goes into the 20 gal tank and we confirm transfer by watching the float gage go to 16 gallons. Then add 6 gallons to the totalizer and press on with current info. The aux tank is empty so no sloshing. It works really well and remember this tank is removable so it can be used as a gas can at an out airport. Take it with you in the airport car get 6 gal at a local gas station an in about 2 min it can be reinstalled in the airplane or just transfer it into the main and do it again until the airplane is full. This system works quite well and we don't have to use 100LL.
Colin
Bill_H
Well Known Member
Colin and John (N1212K) - Great info. Where is the pump? Where do you plumb the output from the pump to the main tank? Do you use an accessory plug as the power source (I still call it a cigarette lighter plug) or something else? Switch location? Are those quick-connect fittings? Get much leakage when you disconnect them? More details please!
Thanks
Bill H N412BR, tail complete, and wings almost complete
Thanks
Bill H N412BR, tail complete, and wings almost complete
RDOG
Well Known Member
Hi Bill,
The pump is mounted on the front left bolt for the main tank. A switched power port from Radio Shack powers the pump. The tank vent is just like the static port but is mounted in the inspection panel under the main spar. Yes they are quick connect fittings form Aero Cabelas. If fuel is in the line you get a drop or two but if you pump the tank dry we get no leakage when we disconnect. We are in the testing phase now and when we are pleased with all the parts we will put more out about the tank.
Colin
eldercaddy
I'm New Here
Yeah, definitely awilson .
Ken Herchuck
Member
Extra Fuel
Wing tanks on a RV12 sound wrong to me. As mentioned about the design factor into the aircraft originally. If you want wing tanks get a S-19.
The extra tank is an interesting idea, especially if you are running MoGas only. I know a local man who checks his MoGas for water content and alcohol content every fill up. Not to say there isnt a quality standard for LL.
I am on the fence about MoGas vs LL in this plane. I know Rotax warns of lead buildup, and some I have spoken to are not concerned about the minor build up. Some run strictly LL. For availabiltiy. Of course this may be in the same discussion as to primer the inside surfaces or not.
I know looking at my local airports, MoGas is not an option, and if you plan a long cross country, say Pittsburgh, PA to Imperial, NE....and you are running MoGas, you could be in for some interesting pre planning.
I do agree, however, that 3 hours in the air, is about the right time to land, get out and get refreshed. Its not a Mooney doing 230 after all. With the fuel capacity on board, and the 4.5 to 5 GPH usage, 20 Gals would be enough to get you to the first fuel stop with a good reserve, and room for headwinds or unexpected diversions.
Wing tanks on a RV12 sound wrong to me. As mentioned about the design factor into the aircraft originally. If you want wing tanks get a S-19.
The extra tank is an interesting idea, especially if you are running MoGas only. I know a local man who checks his MoGas for water content and alcohol content every fill up. Not to say there isnt a quality standard for LL.
I am on the fence about MoGas vs LL in this plane. I know Rotax warns of lead buildup, and some I have spoken to are not concerned about the minor build up. Some run strictly LL. For availabiltiy. Of course this may be in the same discussion as to primer the inside surfaces or not.
I know looking at my local airports, MoGas is not an option, and if you plan a long cross country, say Pittsburgh, PA to Imperial, NE....and you are running MoGas, you could be in for some interesting pre planning.
I do agree, however, that 3 hours in the air, is about the right time to land, get out and get refreshed. Its not a Mooney doing 230 after all. With the fuel capacity on board, and the 4.5 to 5 GPH usage, 20 Gals would be enough to get you to the first fuel stop with a good reserve, and room for headwinds or unexpected diversions.
E. D. Eliot
Well Known Member
Larger tank?
This certainly is a good solution to those of us who want more fuel. I may even go this way.
Why not design and build a 25 gallon tank to replace the 'stock' one? It could have whatever fuel gauge sending device we like, no sight window, and have a larger capacity without affecting the w&b too much. Simpler and would be installed after the test phase if finished.
Maybe Van's could offer this as an option.
This certainly is a good solution to those of us who want more fuel. I may even go this way.
Why not design and build a 25 gallon tank to replace the 'stock' one? It could have whatever fuel gauge sending device we like, no sight window, and have a larger capacity without affecting the w&b too much. Simpler and would be installed after the test phase if finished.
Maybe Van's could offer this as an option.
frankh
Well Known Member
Same holds true for the Lycomings
The Lycs of don't differentiate oil change time based on leaded gas or not, but I do notice my oil is less dark on mogas than it is on 100LL so I tend to opt for 50 hour changes on 100ll.
I too have a hard time burning 100LL for environmental reasons, it just bugs me that I'm puking lead into the atmosphere when there is no reason to be doing so.
Frank
The Lycs of don't differentiate oil change time based on leaded gas or not, but I do notice my oil is less dark on mogas than it is on 100LL so I tend to opt for 50 hour changes on 100ll.
I too have a hard time burning 100LL for environmental reasons, it just bugs me that I'm puking lead into the atmosphere when there is no reason to be doing so.
Frank
Ken Herchuck
Member
Some may argue that flying is not enviromentaly friendly at all. From the effort to make the materials to make the plane, plastics etc, none of it then is safe. Not to mention the fuel usage on production aircraft. Some will always be against "flying" "auto racing" "fill in the blank" because fuel is used. Lead or lead free it will still be an issue. Some arguments can be had for the additives in todays special MoGas blends for different parts of the country, those chemicals in the fuel are not good. What is the PPM for an auto for one year vs an aircraft using 5 gph flying with LL for one year?
Then they will go after the land used for the airports in the first place. Flying is for the affluent, remember? All the electric that goes into VOR's, Infrastructure to the airports, Radar. (what damage is that doing?) The carbon footprint that flying entails? (rental cars, etc) The finger pointers are out numbered by the folks they point the finger at, but for some reason yell louder.
I do not believe "electric" planes will be an answer for some time, or will be another "accepted" alternative by the proper "people". On one hand hate the Chinese, but love their little electric airplane?
For example, on the Chevy Forums, a place I haven't been in a few years, arguments over the pros and cons of the Volt, about how its not good for the environment due to the battery pack, production methods, and on and on. 20% of the population will never be happy about anything, and the other 80% pay for it. The same can be said for the Prius and Escape battery packs, good for 3 years--then what. These are the same people that use wood burners to heat their homes, and tell you that having dogs and cats are bad for the environment. One of the reasons I stay away from forums.
Having said all that, I am an EAA member because I like to see "regular" people build and fly airplanes. A certain percentage are "affluent" which is fine, but I would say that a larger percentage of us are not.
To see the people over at Sonex moved toward an electric aircraft, I applaud them. Practical? Not sure. If you build a glider and can use that energy to get up to soar, then it might be. A Cessna 150 electric? Not so sure. Based on current technology, electric aircraft may exceed performance of electric cars. Who can say? The right technology for the right application?
Every so often "we just don't know". We just don't know what fuel to go to, we just don't know if it will really work in all GA aircraft, we just don't know if we checked it for safety enough. We are just people after all.
Are we doing enough to get people interested into GA? I believe the ranks will continue to fall, as the "great generation" of fliers leaves us, and those in their late 60's fill their spots, I can see GA going the way of service organizations like the Lions Club. Smaller bases of interest will leave us with fewer pilots or people interested in flying. And if user fees get inacted, I can see less people even think of flying.
So mabey with that thought process in mind, should I even bother getting my Sport Pilot Licence this spring, start to build an aircraft this fall? Investing
60K into an aircraft that may be unable to fly due to fuel restrictions 10 years from now?
Yup, totaly off topic at this point.
Then they will go after the land used for the airports in the first place. Flying is for the affluent, remember? All the electric that goes into VOR's, Infrastructure to the airports, Radar. (what damage is that doing?) The carbon footprint that flying entails? (rental cars, etc) The finger pointers are out numbered by the folks they point the finger at, but for some reason yell louder.
I do not believe "electric" planes will be an answer for some time, or will be another "accepted" alternative by the proper "people". On one hand hate the Chinese, but love their little electric airplane?
For example, on the Chevy Forums, a place I haven't been in a few years, arguments over the pros and cons of the Volt, about how its not good for the environment due to the battery pack, production methods, and on and on. 20% of the population will never be happy about anything, and the other 80% pay for it. The same can be said for the Prius and Escape battery packs, good for 3 years--then what. These are the same people that use wood burners to heat their homes, and tell you that having dogs and cats are bad for the environment. One of the reasons I stay away from forums.
Having said all that, I am an EAA member because I like to see "regular" people build and fly airplanes. A certain percentage are "affluent" which is fine, but I would say that a larger percentage of us are not.
To see the people over at Sonex moved toward an electric aircraft, I applaud them. Practical? Not sure. If you build a glider and can use that energy to get up to soar, then it might be. A Cessna 150 electric? Not so sure. Based on current technology, electric aircraft may exceed performance of electric cars. Who can say? The right technology for the right application?
Every so often "we just don't know". We just don't know what fuel to go to, we just don't know if it will really work in all GA aircraft, we just don't know if we checked it for safety enough. We are just people after all.
Are we doing enough to get people interested into GA? I believe the ranks will continue to fall, as the "great generation" of fliers leaves us, and those in their late 60's fill their spots, I can see GA going the way of service organizations like the Lions Club. Smaller bases of interest will leave us with fewer pilots or people interested in flying. And if user fees get inacted, I can see less people even think of flying.
So mabey with that thought process in mind, should I even bother getting my Sport Pilot Licence this spring, start to build an aircraft this fall? Investing
60K into an aircraft that may be unable to fly due to fuel restrictions 10 years from now?
Yup, totaly off topic at this point.
