Q-D fuel fill mod.-Hiller turbine helo

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Q-D fuel fill mod.-Hiller turbine helo9-3-07Below is the turbine powered Hiller that replaced Mark Minkema’s piston-powered Hiller, last year. It has more power and load capacity than the piston, burns kerosene instead of avgas (at $4.25/gallon). The turbine and gearbox cost multiples of a piston version, but they have a known maintenance schedule (in the tens to over $100K), and offer much more reliability than a piston can. If a helo engine ‘hiccups’ at the wrong time.....you’re in a heap of trouble. Especially, when spraying 20’ or less off the deck, or committed to landing, too far into the hover, to get back out. This year the helo is doing more dollar volume than the AgCat. It’s much more versatile and can do many things the AgCat just can’t. With a market value of $250K, the Hiller needs to earn its salt and it does.The helo does not have air-conditioning, as the AgCat—now does. The plexi bubble, makes the cockpit extremely toasty. Mark flies with the right side door off, for some air; but the pilot still gets baked and can be very ornery after flight. He got grumpy with myself and Nick, last week during our efforts to figure out this fill neck mod. We just took it in stride.....after Mark’s cooled down in the office, he’s much easier to talk to.The transport trailer is having detachable, booms to hold and position the main rotor blade during trailering. As of early this afternoon, Monday, 9-3-07, Nick Minkema was doing the finish details on the blade booms, while I was there. Then he has to paint it, in 100 degree weather. The trailered helo and the long 5th wheel support trailer (with its own landing pad for the helo on top of it—an item I finished the design and fitup on, several years ago), will be bouncing down the road to Wyoming; starting tomorrow am-Tuesday, 9-4-07.http://www.weldingweb.com/attachment...1&d=1197703316With 2 trucks and 2 trailers, this spraying helo operation, is completely self-contained, mobile, go-anywhere. The helo can land on its own pad, be re-fueled, reloaded with spray stuff, right at the spraying area. The helo is flown on and off this trailer, which requires the pilot to consistently spot the landing skids on the trailer within plus or minus an inch! (Mark’s amazing good at spotting, even with the wind rippin’. He’s a high time, highly qualified helo and AgCat pilot.) The spraying navigation is done with a SatLoc, GPS computer, similar to what’s used on the AgCat.The spray booms are removed by their quick disconnects, prior to transport. There’s 2 white tanks, one on either side, for the spray solution.8-27-07Twin Cities Aviation’s turbine helo, will be trailered to northeast Wyoming, after Labor Day for contract noxious weed spraying, for a county there. It will be cooler-there, too! This mod. Is to enable the refueling by another helo operator (who will also be spraying) located there, who uses a quick-disconnect fuel fill.     The Hiller didn’t have this, so it was tee’d into the existing 3” o.d. Aluminum tubingfuel filler neck, which mounts via a bolt flange to the top of the fuel tank.http://www.weldingweb.com/attachment...1&d=1197703367    Establishing, ‘what’ the alignment of this 1” S. 40 alum. pipe was to be—since there was very little room for error, was ‘touchy’. Above is initial test fitting to establish and verify light scribed lines, as to exact location of this pipe.    The fuel fill hose when attached to this, is relatively heavy—requiring that the pipe be strongly mounted on the thin wall (.050—18 gauge) tube filler neck. Both the 1” pipe and the 3” fill neck will be fastened to the frame tubes with Adel clamps, on final install; to help stabilize this unit.http://www.weldingweb.com/attachment...1&d=11977034031-I cleaned, trimmed and rolled a doubler plate from .063 6061-T6 sheet, trimming it to fit half way around the circumference of the 3” tube filler neck. The rolling was made slightly smaller, so this doubler would clamp itself fairly closely to the neck—which, really helps fitup.****Always make a curved doubler, smaller to clamp onto the work    TIP TIME----after making alignment marks with pen, pencil or marker—scribe these lines lightly with a sharp carbide scribe—BEFORE the parts are sanded or polished—or you will loose your alignment marks. Obviously, in some applications—such scribe marks might be considered ‘stress risers’....so you can carefully sand them out, if you wish. I just leave’em in---since this is just a part for a helicopter.      Another option is to locate your scribe marks in the areas that will be welded over.2-Templated then cut an 1.250 id hole in the 3” tubing, templating and cutting a 1.375 id hole in the doubler, then carbide burred the ellipses. The ellipse in the 3” tube is purposely smaller than the one in the doubler plate. This is to allow an area exposed on the 3” tube, to be welded fully, all around, to this doubler. The doubler was tacked on its perimeter, prior to the ellipse welding. I wanted this doubler assembly to have maximum stiffness. Run back to airport to check alignment and fit a poster board template to gauge the angle of the filler pipe, when in the weld fixture.3-The pipe was tacked in one place-only, to this inner ellipse weld, after setting up the assembly in a fixture, to support it and verify horizontal and circular plane locations.4-The tacked assembly alignment was then checked-again on the helo. Sutter County Airport is 6 blocks down the street from my shop, conveniently.5-Assembly goes back into fixture, then weld most of the ellipse—after tacking it around, in about 10 places—to help prevent weld distortion pulling it out of alignment. On an angular, elliptical pipe to pipe fitup—you can have tremendous pulling and mis-alignment.6-2 gussets from .125 plate were templated, trimmed, polished and tacked in place.7-Back to the airport..(again!).....for another check on alignment. It had not moved. (relief!)8-Back to shop, to finish weld—below:http://www.weldingweb.com/attachment...1&d=1197703429Above, won’t get any awards for good-looks---I could care less. (It's just a part for a helo    )Due to all the fitup tacking, the welding has to just wet up, around and over the existing tack welds. Fusing everything in, flattening it down, pulsing over the bead—is nice and pretty.........but the melt and burn-thru one creates by doing this on the inside, makes a weakerjoint and causes other problems.    It’s seal-tight and--(as usual!) there is NO BURN-THRU OR MELT-THRUinto the inside of the 3” thinwall tubing.On thin aluminum, I can control melt thru, very, very, very well. http://www.weldingweb.com/attachment...1&d=1197703449The filler neck above, in primer. It will be epoxy top-coated. Paint by TCA. Attached ImagesBlackbird
Reply:nice work and nice right up thank you,and know i want a heilo  ChuckASME Pressure Vessel welder
Reply:Looks alot like the old school TH-55s the Army used to use to train it's helo pilots a long, long time ago.