Venting Deflations

by Don Piccard

This column will appear long after most of the big noise about who invented what in deflation systems for hot air balloons has withered away, but several people have asked me about it and so I will make some comments.

When the British saw my Red Dragon nearly thirty years ago (they called it The Red Monster), they saw the value of my original lobular gore design. But they couldn’t make my "Window curtain" side vent close up tightly on their version (Ha! Mine didn’t let out much heat even when wide open.) They put bungee in to pull it closed and that worked. I felt mine closed perfectly, if rigged right, and didn’t even bother to check to see if bungee was O.K. to use in a hot air environment. I just assumed it wasn’t.

Then about 1980 Dick Roberts of Kalamazoo, Michigan had one of my 21,000 cubic foot "Pick-Ups", that had no side vent. It had a circular overlapping top that was held loosely in place by a daisy chain of loops. It could be vented in flight a little, or deflated for final landing by releasing the loops and pulling the disc out. Dick replaced the loops with several five foot lengths of bungee each anchored radially out on the balloon fabric. I was sure that with the high operating temperatures of that small balloon the bungee would fail almost immediately. Then I checked with the bungee manufacturer and found Mil Spec exerciser cord that was designed for 300 degree F. use.

Now, in Dick’s modification, the bungee held the top disc in place automatically with no difficulty in getting just the right adjustment, but it held it out so taut that it didn’t settle up into the opening like Tracy [Barnes Parachute Top]. It always went into place dead center, but the air just whistled out with the disc chattering up and down. That caused me to perfect the inner seal, which is a flap inside the balloon from the edge of the opening leading out radially. While the bungee held the disc taut, the seal could settle down against it like a doughnut cushion and make a sealing area.

Now, with elastic centering cords, the top could be pulled in towards the center instead of down, making it much easier to open. In order to get long enough sections of bungee to let the top be pulled into the center and yet keep the attachment points high enough so they wouldn’t pull the disc down themselves, I used pulleys at the anchor points and then led the double length of bungee back to the opening. With the pulling lines very short, like bowstrings rather than parachute shroud lines, a gentle pull on the vent line curls the top in and it vents like crazy. You don’t have to pull the whole disc down against the air pressure.

That was what I used in the envelopes I built for Solo System balloons. (Dick Roberts sold one person ultralight balloons under the Solo System name in the mid to late 80’s. Ed)

Then I added a second "Cinch line" running around the disc through little rings. It pulls even easier (but many feet hand over hand) to really purse the disc up for a simple final landing deflation system independent of the other line. Redundancy! Either line can be used to vent in flight or to deflate at landing. When the cinch line is used, the basket can be bouncing along on its side and you still don’t pull yourself out of the basket, but yet the top stays open.

That is what I used on the Piccard P-80 and now am putting it on the new SkySailor balloon Type Design which is now in the final stages of an FAA Certification program.

Other inventors, some seeing or taIking about the Solo System or Piccard P-80’s, perhaps, like me at first, didn’t like bungee. Without bungee, they have had to let Tracy’s original non-extensible centering cords loose in order to permit the disc to pull in to the center. So then they have to use a second line to manually pull them back into place.

That seems more complicated and could fail in embarrassing ways. It may be an improvement and worthy of further patents, but SkySailor seems to be happy with my top as it is. It is so simple and fully automatic in flight and also self setting at inflation IT DOESN’T EVEN NEED VELCRO TABS. And I’m happy to report it passed the FAA Type Certification Flight Tests beautifully for the SkySailor Ninety. Sliding that in between perpetual rain storms on Martin Luther King Day in California took efforts above and beyond the call of duly by the California FAA (volunteering to do the job for the Chicago office). Many thanks. But that’s a story for another time. P.S.: I don’t get any percentage from SkySailor-my deal with them was a straight sale on the patent, type design etc.

For those of you have read this far, a reward: when I got back to the icebox from "sunny" California and was doing some clean up in the loft I found a long forgotten General Balloon Corporation built Piccard AX-7 with zero hours! (GBC manufactured and sold Piccard balloons. The company went out of business in the early 80’s. Ed)Since I’m so happy with the SkySailor I can let this one go now to someone that needs a super balloon at a super low price. (It has the two inch Velcro with the Capewell safety lock deflation system, Nomex mouth, Twin burners and a 3x4 real rattan basket, etc.) Call me at 612/333-6912, but hurry. With spring on its way I may start flying it and then it won’t be zero hours anymore.....