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ww2planes

Well Known Member
Well I have cut the material and made a mock up of my ER Tank. I am only putting one in due to my flight mission profile. Based on the numbers the one tank should get me 9.3 gallons. It will work very similar to the SafeAir 1 system with a significant design change to get the additional quantity. I figure that I now have a 45 minute reserve and will be able to extend my range by a comfortable margin.

It is straight forward to install and is easier if you are able to do it while skinning the wing but I am sure that I could do it in a retrofit situation as well. I have an estimated weight of less than 15 pounds for the entire system. I will know more as the design gets closer to being completed.

I thought about making one for each wing but I don't think that either my wife nor I can sit that long. If I did however, I would be looking at nearly two extra hours of flight time and would have over a 1000 mile range. Sounds appealing but that may be too far in one shot for me.

Forgot to mention, Weight and balance issues should be nil with my design.
 
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Any pictures yet?

Happy Easter, Bill !

Whenever you have pictures of the mockup I probably speak for several when I say I'd love to see them.

Best,
Doug
 
I have 17 extra gallons and use it

I have 17 extra gallons in two span extending tip tanks and I use them. You mention weight and balance is not an issue but if you put an extra 50+ pounds of fuel in one wing you are going to have to compensate for that and the tank weight somehow. I would go for the 1000 mile range two tank configuration and land with a little extra reserve. You know the old saying that you can only have too much fuel if you are on fire - I think it has merit. Theoretically, I should have 5.5 no reserve hours at a conservative planned 10 gal/hr burn rate on my O-360-A1A but I get VERY unsettled when I hit the 4 hour mark and I'm not within glide range of my destination.

Bob Axsom
 
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Good Point Bob

I had thought about doing both tanks but I built the first wing without the ER Tank. I had figured that I can use my aileron trim to offset the heavy wing if it were an issue. I plan on building a trim tab into the aileron. I am putting the tank in the right wing and I am fairly sure that my chubby physique will offset the heavy wing. I theorized that a 9 GPH Burn would yield a duration of just over 6 hours if I had both tanks. That will never happen so I decided to just go with the one.

By the way, are there any builders out there that would be interested in these types of tanks?
 
ww2planes said:
By the way, are there any builders out there that would be interested in these types of tanks?
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I'm building eventually, so I'd like to see some more concrete info...
 
Interested yes, but what are the advantages over just pushing the main tanks out one more rib, and making new skins? That's what a -4 guy I know did.
 
Reply

I did not want to modify the outer leading edge for several reasons. I did not want to re-make the rib or deal with the skin, a new bulkhead and figuring out how to attach it to the spar. Besides, I am entertaining the resale advantages of my design and if I modified my leading edge I just don't think that many folks would want to remove ther leading edge and make it all over again and deal with that many headaches. New install is not so much and issue but a retrofit in an existing wing would be terrible using the leading edge theory.

Thanks for the interest.
 
Right, for retrofit my idea for the mod would SUCK... Do you have drawings of how it's gonna work?
 
There are just couple of modifications I've planned and ER tanks are one of them. Therefore all ideas are welcome and I'd like to see different ways to implement them before choosing my way to do it. Also interested details like how thick material you are using and such...

Anyone know details about SafeAir tanks? Thickness etc.
 
Mock up

This is an overall of the system. I had to redesign the end tank as I did not have the quantity that I wanted yet. This is the new tank. I checked the clearances today and it has about a 1/2" inch at the closest points so I hope that will be enough.

http://img115.imageshack.us/img115/8000/p10002035zk.jpg

After doing the math I show that these will hold about 10.3 gallons. That is the perfect number for me. I figure that conservatively, there will be about 1/2 gallon of unusable product in the tank. At 9.5 usable this is the perfect size.

Now to ordering the hardware and the welding of the pieces. I hope this thing works.
 
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ER tanks

I had given the ER tank(s) some thought. The wife, (she will be my most frequent co-pilot), says 4 hours at one time is just a little more than enough time in the sky without a break. She likes to stretch the legs and powder the nose more often than I do.

Then again, I don't always have to use them - now do I ! ? ! ? ;) :)

Robert
 
ww2planes said:
p10002035zk.jpg
Click to expand...

Looks great! I'm definitely interested in following your progress.
 
ER tanks

kevinh said:
Looks great! I'm definitely interested in following your progress.
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Me too. I agree with Bob that you may want to reconsider your idea of only having the tanks in one wing. An extra 60-70 lbs will be almost impossible to compensate using aileron trim, and even if it were, it would add a lot of unnecessary drag. If you really only need 10 gallons, make two smaller tanks. Best of luck!
 
Robert M said:
I had given the ER tank(s) some thought. The wife, (she will be my most frequent co-pilot), says 4 hours at one time is just a little more than enough time in the sky without a break.
Click to expand...
I would not build ER tanks to make extra long flight times but to avoid some of the extra fuellings. So instead fuelling on every airfield I'd like to keep going without worrying how to fill up the tank in the current airfield. That also gives you reserve if after all there is no fuel available for some reason at the place you land (fuel tanks blown up second a go, so you couldn't check it before ;)) -- assuming you that you already didn't burn all fuel.

So 2 - 3 hour flight time is just fine, but I'd like to do 2 - 3 of them before really need to stop.

Edit:

to Bill: it's nice to see that someone is going to test the idea i had of ER tanks (two tubes instead of one). Defenitely want all the details!
 
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Pirkka said:
I would not build ER tanks to make extra long flight times but to avoid some of the extra fuellings. So instead fuelling on every airfield I'd like to keep going without worrying how to fill up the tank in the current airfield. That also gives you reserve if after all there is no fuel available for some reason at the place you land (fuel tanks blown up second a go, so you couldn't check it before ;)) -- assuming you that you already didn't burn all fuel.

So 2 - 3 hour flight time is just fine, but I'd like to do 2 - 3 of them before really need to stop.
Click to expand...

I agree. The fact that the fuel is onboard doesn't mean you have to fly until reserves. It would be very comforting to know I had plenty of fuel onboard at my intended point of landing and find out the pump broke 5 minutes before I arrived.
 
One Wing ???

I would have to strongly echo what others have said about adding weight to one wing. These airplanes are light and well balanced, especially in roll.

I'm really sorry to say this but I think this is a very bad idea. I think after a few flights, you will realize this and then be faced with a very difficult decision. I would do both wings or neither. No in between.

BTW, in my 4, 20 minutes of flying on one tank causes a slight wing heaviness. Tells you it's time to switch tanks. That's only about 3 gallons burned. You might not notice this in a larger (more clumsy) airplane but in an RV, you will REALLY feel 10 gallons difference.

Good luck with your project.

John
 
I Give

I am going to do two tanks. As one of my wings is already built this would be a good retrofit exercise. I don't always have to have fuel in them nor do I have to fill them all the way. I am going to get the tip fitted on the wing this weekend and ensure that my clearances inside of the tip are good. I will then get some plumbing items and have the tank welded. I am anticipating about a month for completion of the first tank.

I am going to double and triple check my numbers to make sure that I am not talking out of my ear. Each tank should have at least 10 gallons in it and the usable amount I will leave up to anyone who buys them.

My target price is going to be similar to those already on the market. I just don't see why they need to be that much so, in the end, depending on materials cost and assembly cost I am hoping to be in the $1,800.00 range. I could save money by providing a kit and sending out the pieces for the builder to assemble, along with their favorite welder.
 
Extended range tanks

Matt Luthi in Australia has a pretty good website for his RV that entails beefing up the fiberglas wing tips, bulkheading them, adding filler, vent, drain and outlet at each wing tip. Total capacity gained: approx. 24 total (12 each side) U.S. gallons of your engine's favorite beverage or approx 2-1/2 hr. add'l endurance at typical cruise settings. I'm doing the about the same procedure to mine. :)
 
Thread resurrect

What happened to this idea????

Im thinking MORE fuel for the RV 7a

Frank
 
Frank.... What are you thinking? This is the first I have seen of this(two tubes). A very good friend of mine is a welder/fabricator by trade. He does beautiful work with aluminum. I am also interested in this idea. I just don't like the 1800 dollar price tag. If we designed it, I know he could build it. Extra 20 gallons? Is this right?
 
I like

The napwars method as it uses all the stuff i already have a part from a few baffles..One can also build this tank to anysize..

15 gallons each side sounds nice!

Need to think about the line of AN3 rivets being strong enough or not.

Thanks

Frank
 
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