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Building Tips and technical articles. => 1/2 A building. => Topic started by: Dan Bregar on July 31, 2011, 09:12:17 AM
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Hey guys. I'm building a Baby Flite Streak with a AP Wasp .061 engine. I'm looking for a tank for it. The only thing I've been able to find is the BH-521 1oz. standard wedge from Brodak. I have about 1-1/2" from the back of the engine to the leading edge, and this tank will fit. 1 oz. should be plenty. Anyone know of any other options ?
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(Clip)
Anyone know of any other options ?
Make one from the K&S tin sheet.
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I can do the pattern with an AP Wasp on 27 cc of fuel with time to spare. That is just under 1 ounce (29.57 cc). The Baby Flite Streak should move right along, so you will probably need even less fuel.
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Yes I could make one from scratch if I had to. I was hoping to spend the hours it would take me to make one from scratch on something else. Maybe I'll just get the Brodak tank and take the ends off and re-plumb it instead of starting from scratch. Unless I hear a better way from you guys. ::)
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Well I hesitate to suggest it but a simple floppy-balloon tank works better than it has any right to. Not very high tech...
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How long does the balloon last ? And when it breaks, I suppose raw fuel goes all over, correct ? I remember the Firebaby had a balloon tank back in the day. I wonder if the balloon quality is better or worse than it used to be. Kinda like the silkspan dilemma. One thing for sure is the balloon tank is light.
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There two companies producing metal fuel tanks; Acme (brass) and Brodak who purchased the tanks and machinery to make then from Perfect Parts Co. Balloon tanks weigh almost as much as metal tanks due to the container that you must have to hold them. 1 ounce seems kind of much, 3/4 oz should be enough.
two cents
Larry
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Fuel requirement depends on several things: Plane size and speed, line length, and whether you are flying a full pattern or just noodling around. For me, flying a full pattern with a couple of extra laps after on 45' lines with a 6x2 prop, I need the amount stated above. If I get a rich run, even that isn't quite enough.
RSM also makes very good tanks. rsmdistribution.com
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How long does the balloon last ? And when it breaks, I suppose raw fuel goes all over, correct ? I remember the Firebaby had a balloon tank back in the day. I wonder if the balloon quality is better or worse than it used to be. Kinda like the silkspan dilemma. One thing for sure is the balloon tank is light.
the balloon lasts typically a couple of months, but degrades gradually. You'll notice it getting sticky long before it starts to leak. This is not a pressure tank, the balloon is not stretched, but just a limp bladder; I call it a "floppy balloon tank" to emphasize that. Common party balloons work fine, available in most any size. I use 35mm film canisters for containers--very light. for more capacity you must also use a larger container of course.
--Ray
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Guys (Larry & Larry)
The only tank I can find close to 1 oz. is the Brodak BH-521, which looks like the old Perfect style, and fits a profile nicely. I know RSM has their own tanks but I don't see one around 1 oz.. Am I missing something ? ::) I found a 1 oz. Acme brass tank but, I'll bet brass is heavy. If I need nose weight I could go brass, but I probably will be on the nose heavy side anyway. I will be flying on 42 ft. lines and I want enough fuel to complete the full pattern.
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Dan, I built my Brodak Streak using a metal wedge tank by Brodak. I can't remember which one exactly. The problem I was faced with using the wedge is that it puts your feed line right into the back of your engine. I had to severely bend my tank feed line downwards as soon as it exits the tank due to interference with the engine case. It's so close that every now and then it actually cuts the fuel line. It also places your fuel line outboard which now makes the engine struggle for fuel draw due to the slight bit of extra tubing it requires to get you back around and onto the spraybar. I highly suggest reworking the tank plugging the existing hole and making your fuel feed exit the bottom of the tank but close to the profile body. This of course means leaving the pipe in the tank in the correct location. Ken
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Ken
I'm with ya on that. Putting the end of the feed line where they put it means you need another 1/2" or so between the engine and tank, which on a flite streak of any type is a problem cause of the short nose. Yeah I will either change the pick-up tube to the top or bottom like you mentioned. ;D
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The brass tanks are not heavy just expensive.
Larry
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Thanks Larry. Then maybe I should consider the Acme also. Does it come with an autographed signature from the Roadrunner ? LL~
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I owned a hobby store once. I bought up a lot of boat accessories once that were not packaged. I packaged them and names them "Brand X" it get all of the free advertisement. It didn't work :-\
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I would seriously caution against using the Acme tanks unless you plan to totally do a complete renovation on them. More than once I have seen horrible corrosion within them. I've seen white powdery deposits almost like you find on a old car battery as well as black and gray deposits within them. These were brand new tanks. On another side note we all know what happens to brass when exposed to glow fuel and this typically gets worse when the plane is in storage. If your using the tank on a regular basis this shouldn't be a problem but eventually it will. I've experienced this with older Darwin tanks as well. I suppose if your in a pinch than it will work but I would surely suggest using plated tin tanks. Ken
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Thanks Ken. Point well taken. Didn't think about that. :)
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eBay is full of old Perfect tanks. At least a half dozen for sale every week.
I have a Perfect tank chart with sizes and tank #'s but my scanner is broke. Maybe someone else can post a chart.
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Mount the tank on the inboard side it will give you more room.