The concept (Buoyancy Assisted Airship) deserves a single syllable word that describes a rigid airship whose buoyancy is controllable or variable.I suggest zep. It's in usage already, but undefined. One might incorrectly call a blimp a zep.
The term zep is illiterate slang, and should not be used. Please don't insult the memory of Count Ferdinand von Zeppelin by using that flippant little expression. Thank you very much. Please do an internet search on rigid airship and learn more about airships: what they are, how they work, and what has been tried in the past, before you start asking questions that don't make a whole lot of sense. How would you use waste heat from an engine to increase the lift of an airship? There does not seem to be any practical way, and the question seems-frankly-nonsensical. Engines provide forward thrust to move the airship. Lift is provided by lighter-than-air gas. The airship is already full of gas and is at the maximum lifting capacity provided by its gas volume. Heating the lifting gas would only waste gas by forcing some of it to be released into the atmosphere. Please give up this line of inquiry and trust the hundreds of very smart people who have studied and experimented with all aspects of lighter than air flight now for more than 10 years. Everything that might work has been tried.
You should make an effort to understand thermodynamics. Nothing comes free, any attempt to harness what appears to be wasted energy could in fact result in more energy consumption. What you are suggesting is agonizingly close to the myth called Perpetual Machine. It is easy to understand why any SUCCESSFUL attempt has not been made if you realize that the main products of hydrocarbon fuel combustion is water vapor and carbon dioxide. Not the best things to be kept in a lighter-than-air vehicle. In any case, putting a block in the exhaust is not a wise thing to do. ------------- --------------- ----------------- --------------- -------------------- ----------- ------------- Edit: Two problems, one tapping the engine exhaust will reduce your jets efficiency and two, the exhaust is heavier than air because of the heavier gases and water content. You will end up using more power than conventionally heating normal air. Adding a heat exchanger would be another mistake, the energy exchanged would never justify the weight. The website clearly says why the usage of exhaust gases apparent energy content is not practical as it looks prima facie. So I wouldn't agree it is irrelevant and it also introduces the two laws of thermodynamics.
