PDA

View Full Version : Question about balloons


UniFoxOs
2nd Feb 2006, 12:29
One of my better Christmas presents was a flight in a hot-air balloon.......over the Serengeti!

It was a fascinating flight and I was placed next to the pilot so I was able to ask quite a few questions about it, but he was fairly busy with working the balloon and pointing out the game to the punters so I was left with still a couple of points that I was puzzled about. Maybe the pprune knowledgebase can help.

First - how does the basket remain oriented facing the direction of flight? - Surley there must be some leakage of air out of the balloon, and as it is unlikely to be symmetrical it would tend to cause a jet effect to rotate the balloon? Also short wind gusts, that would be too brief to accelerate or decelerate the whole assembly, would have more effect on the side of the basket with the bigger pax in it (more wind resistance). These effects would be small - but over a flight of an hour I was impressed that we were still facing forwards.

Second - the balloon needs occasional blasts of hot air to keep it airborne. The pilot gives it a blast of about a second, it rises fairly quickly a few feet, then gradually falls back over the next 20 seconds or so, when another blast is required. My question is - why is there not a facility to run the burner at, say, 5% power continually to maintain height. It would probably be possible to do this fairly quietly, which would be more peaceful than silence for 20 seconds then a really noisy blast for a second or so. OK, I accept an occasional "top-up" would probably still be needed, but if the continual-running jet was adjustable the pilot could probably fine-tune it so that top-ups would only be needed every few minutes.

UFO

steinycans
2nd Feb 2006, 12:55
hi some interesting things ive never thught about either. i havnt been in a ballon yet but one day i am hoping to complete my ballon IFR rating (haha).

so lets start with the assumptions

about assymetric jet affect of leaks, im guessing but perhaps they have valves in the balloon that keep the presssur to a managable level so the leaks dont have that much of an effect?

an for the 'running at 5%' instead of short blasts, perhaps the heat generated by running at 5% doesnt raise sufficiently into the balloon?


Anyone else?

G-CPTN
2nd Feb 2006, 13:05
The pilot has a device that acts as a rudder. How else could he steer the thing to go in the direction that he wants?

sir
2nd Feb 2006, 13:06
I'm not a balloon pilot either - but interested nonetheless...

I would think the constant running of the burner at 5% would lead to the top of the balloon heating up too much - it will always be taking the brunt of the heating. Bursts give it a chance to cool down. It's the air we want to heat - not the balloon itself. Imagine blasting a hot air gun into a plastic bag - a quick blast wouldn't melt the bag, but constant running at low temperature would cause the end to melt...

As to how it kept pointing the right way - absolutely no idea !

Parapunter
2nd Feb 2006, 13:19
At ones service...http://www.cameronballoons.co.uk/hotairballoons.htm

steinycans
2nd Feb 2006, 14:29
"Search Results

Search results for: ifr baloon


No results found."



dissappointting :(

ExSimGuy
2nd Feb 2006, 15:43
As to how it kept pointing the right way - absolutely no idea ! You can't see them from inside because you'd have to hang over the side, and you can't see them from below due to the construction, but a baloon has a "tail", similar to the concept of a traditional kite. This hangs from the rear of the base of the basket and is made from a thin wire with little transparent plastic "bow-ties".

Near the baloon end, it mostly hangs downward due to the small, but significant, weight of the construction. Nearer the free end, it is "trailing" more.

Although this is not a great deal of force, it's enough to keep the baloon pointing sufficiently straight-ahead to convince most people.

Jerricho
2nd Feb 2006, 15:47
"Search Results
Search results for: ifr baloon


Not in my fricken airspace!!!!! :suspect:

G-CPTN
2nd Feb 2006, 16:51
Do you mean Beardy had to land everytime it got dark?