Blimp Questions
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Apophis
Resident Iconoclast
Well,
As far as speed is concerned, the best answer is "it depends." Airships are much more affected by wind than other types of aircraft, so knowing what the winds will be doing is always a critical portion of our flight planning.
The airship I'm currently flying has a Vmo of 48 Knots indicated. Since I've been flying, I've seen ground speeds anywhere from 10 knots (that day was brutal) to 52 knots. Of course cruise speed also depends on the cruise power setting we use. 25-35 knots over the ground is usually about normal on a relatively calm day.
As far as range is concerned, once again, that depends on our power setting and the wind conditions we experience. The a-60 airship I currently fly holds 69.0 gallons useable fuel. 2400 RPM gives a total fuel burn of 6GPH. At 2500RPM the cumulative fuel burn (both engines) is 7GPH. At maximum continuous power (2600RPM) you're up to just over 8GPH (these figures are for the Limbach engines, not the Rotax).
The longest I've currently spent in the airship without refueling or getting out was a hair over 10 hours.
The two models that I fly at this company have either twin 80HP Limbach L2000 ECI engines, or Twin Rotax 912F3's. There is no mixture control for either.
As far as speed is concerned, the best answer is "it depends." Airships are much more affected by wind than other types of aircraft, so knowing what the winds will be doing is always a critical portion of our flight planning.
The airship I'm currently flying has a Vmo of 48 Knots indicated. Since I've been flying, I've seen ground speeds anywhere from 10 knots (that day was brutal) to 52 knots. Of course cruise speed also depends on the cruise power setting we use. 25-35 knots over the ground is usually about normal on a relatively calm day.
As far as range is concerned, once again, that depends on our power setting and the wind conditions we experience. The a-60 airship I currently fly holds 69.0 gallons useable fuel. 2400 RPM gives a total fuel burn of 6GPH. At 2500RPM the cumulative fuel burn (both engines) is 7GPH. At maximum continuous power (2600RPM) you're up to just over 8GPH (these figures are for the Limbach engines, not the Rotax).
The longest I've currently spent in the airship without refueling or getting out was a hair over 10 hours.
The two models that I fly at this company have either twin 80HP Limbach L2000 ECI engines, or Twin Rotax 912F3's. There is no mixture control for either.
Murdoughnut
Well sized member
No, I only fly my mother-in-law to destinations in Florida.
Apophis
Resident Iconoclast
Mark815 said:
Maximum operating altitude for the A-60+ is 10,000' MSL. It is 6000' IIRC for the Rotax model. You have to remember though, the purpose of airships is generally advertising or aerial coverage for events. Therefore we usually spend our time below 1500' AGL or so.
Also, how high we can go depends on a phenomenon called "pressure height". We can't fly above pressure height without dumping helium. Pressure height varies with temperature, elevation (pressure) changes, as well as the quantity (mass) of Helium inside the envelope, among others.
Certain things you would never think about in an airplane are actually quite critical in airships.
Apophis
Resident Iconoclast
X-Forces said:
Yes, we have a Vmo. It's 48 knots indicated on the one I'm currently on, and 52KIAS on our Rotax models.
It is extremely difficult to exceed Vmo in these things. In fact, I'm really not sure how you would be able to be in a situation where it could be exceeded. Even at max power you're usually nowhere close to Vmo. Even in a steep descent, your pressure limits would be exceeded before reaching Vmo.
Just like any aircraft, structural damage is a possibility above Vmo.
In airships, airspeed isn't really as important as it is in airplanes. We are much more concerned with pressure control and management, as well as static condition.
Planning is much more detailed in these things than anything I've ever done in airplanes.
Apophis
Resident Iconoclast
Fencer said:
No problem, Fencer. Especially considering how awesome your SU-24 thread has been with all the photos and information!
Airships are frequently thought of as slow and ungainly, but I'm really enjoying flying these things. It's such a unique and rare form of flight.
I find the term "creature" to be quite accurate. An airship really is like a living, breathing creature. They have to be taken care of and are quite fragile.
A member of our ground crew always stays with the airship when it's locked on it's mooring mast, 24/7. Basically he or she watches the airship, ballasts it according to the changing conditions, and takes hourly pressure readings and monitors everything.
They really do have to be "babied"!
Mark815
Well-Known Member
wow I didn't realize that! That's pretty crazy!
Apophis
Resident Iconoclast
I_Money said:
Right now, I've only been over some minor league baseball games. I'll be on our TBS themed Conan O'Brien airship starting tomorrow doing MLB playoff games. That contract goes until the middle of November. Our Metlife airships do golf tournaments, as well as NFL games on Sundays among others.
Also, if you've seen the DirecTV airship over the US open (tennis) or NFL games, that's also our company. I don't fly the DirecTV airship, it's a much larger model with a 170,000 cubic foot envelope.
As for your other question, if we have to go across country, we generally fly the airship there. It takes awhile, especially if there's weather that delays us. Generally the airships are only deflated and packed away when we send them to do overseas contracts, or once a contract for a particular ship ends. The Conan contract I mentioned earlier ends in November, and after that, that particular ship is going to be deflated. I'll then move to another operation.
Apophis
Resident Iconoclast
Minuteman said:Do people ever use the helium to make their voices sound funny?
Does that ever get old?
Hah, nope. Helium inside the replenishment tanks is under very high pressure, plus, it gets very very cold as the gas expands leaving the cylinder. Not a good idea to be breathing that!