Textron has teamed up with California-based ZeroAvia to develop a hydrogen-electric powered Caravan. The companies want to get an STC for the design, which will carry hydrogen in a wing tank to run ZeroAvia’s ZA600 powertrain in place of the PT6 that powers standard Caravans. The two companies said in a joint release that carrying the hydrogen under-wing leaves the fuselage free for its normal passenger and cargo load. Performance projections were not included in the release but the duo hopes to have the plane in service by 2025.
2 issues I see here. Ten knots already went away with the cargo pod, how much more speed is lost with those huge tanks hanging on the wing struts. With that extra loss of speed I can’t see this configuration maintaining flight into known icing certification. Laws of aerodynamics mean additional power will not mean very much increase in cruise speed. And getting ice on those tanks just greatly increases the drag created on an airplane that normally does not handle ice very well.
@Matt W. - Well, I suppose that still leaves all the warmer parts of the world for it to work in…?
It strikes me that ‘bolting-on’ a H2 FC drive-train will never really work and the fact that no-one is even talking about a a ground-up H2FC aircraft suggests that this is just another ‘tinkering with H2’ pipe-dream that a few individuals will get rich over due to the almost required government interest - and tax-payers money - that will be lavished on it.
We really need to come up with a ‘fuel’ (if that’s what’s needed) that carries renewable electrical (?) energy in a highly portable form and which does not involve wasting 50 to 70% of the original energy used to make it (as H2 does). This would, in my opinion, be a much more worthy ambition for all the time, energy, talent and money going into H2-based systems that have had billions squandered on them over the last 50 years to very little practical effect.
Wonderful. Now tell us how you make, compress and/or liquify the hydrogen. I hope not steam reforming natural gas, which produces CO2 in the process.
Yet another stupid boondoggle. All of aviation isn’t exactly low hanging fruit for CO2 reduction (around 2 to 3% of human caused CO2 emissions). That’s if you are silly enough to believe, without any definitive evidence, that CO2 emissions from human activity are a problem.
We are in an interglacial. What we think of as “normal” climate has only been around for 11,000 years in the current interglacial. Enjoy the warmth, the ice will be back soon enough and then things will get grim.
Realise also that most academic “scientists” who tell you all this is a problem would make good livings as used car salesmen.
Best way to handle hydrogen as a fuel is to store it attached to nanoscale backbones of carbon atoms. Stores at room temperature, dense and easy to handle. I’m going to call it Avgas and Jet A1.
Great comments here. Another claptrap idea that would not be pursued were it not for government money and naive investors. All based on the false premises of CO2 being bad and humans causing climate change. Stupidity and ignorance are expensive.
One average wide-body burns approximately 30,000 gallons of Jet juice per day or enough to power 600 flight hours per day of Caravan flight. Why not power the bigs with a tiny reactor. The technology already exists. Pollution problem solved, range problems solved, weight issues solved, post crash fire problems solved………and while we are at it let’s power the electrical grid with tiny reactors…………
The sound you hear is me clapping and applauding your comment and my morning laughter. Strong work, Mike B. very strong work!
Another argument for stored solar energy in those nanoscale carbon backbones is that its energy density is much higher than electrical energy storage devices. Based on my experience walking in a forest on a summer day, that solar energy conversion to stored nanoscale carbon backbones conserves thermodynamic energy too, which we release in the winter to heat our camp and roast marshmallows.
If there is any way replace our existing fleet and to stop burning fossil fuels in the process, then it’s going to require new power plants and air frames. Correct?
Here we have Textron Cessna, one of the few companies on the planet with the ability to actually get new planes through the process and onto the market, deciding to use the STC route in order to avoid certification hassles. One could easily argue that Textron’s true competence is no longer design and manufacturing but dealing with government. IMO, that’s just the plain truth.
Couldn’t they just as well have written a press release that the entire certification process is what really needs innovation and upgrading?
The true problem trying to be solved is how to store enough energy to power an aircraft for a reasonable amount of time within the weight and space constraints allowed for each specific aircraft design. The current solution is to combust a liquid fuel to convert it from chemical energy directly into thermal and mechanical energy. It also happens to be one of the easier methods, but it has its own drawbacks.
What I think a lot of people overlook is that a proposed alternate solution doesn’t have to be the final solution. It’s an iterative process to discover what works and what doesn’t, and sometimes one proposed solution can lead to something entirely different that may be the breakthrough that was needed for something better. History is filled with experiments that lead to something entirely unexpected, but you’ll never know unless you try.
That’s how I see this and all other alternate propulsion systems being proposed: an experiment to try something different, because if you always do the same thing, you’ll never learn something new.
More weight, more drag, and then adding an even less energy-dense power source than even batteries. This must be either a joke or the acme of delusional pseudo-science.
As I have commented in other threads the impasse for electric airplanes is not the motor but the battery.
As I have also opined HFC would work, so IF we are going to be forced off safe and proven IC technology this is likely the best pathway.
Electric motors are superior in many (maybe even most) ways to IC but batteries cannot work in aviation due to weight and the realities of the periodic table dictating rules of electrical potential.
The other point in favor of this is here we have a genuine aviation company proposing a genuine aviation product. Not some paper startup making a paper airplane.
“Build a better mousetrap, and the world will beat a path to your door.”–Ralph Waldo Emerson
It’s been years since the basic mousetrap was invented–and despite all of the attempts–it hasn’t been improved upon.
Today, there are a lot of people trying to build “aviation mousetraps” (alternatives to liquid combustibles)–but so far, nothing beats the tried and true ones. Like the classic mousetrap–liquid combustibles WORK, they are relatively CHEAP–they are ENERGY DENSE, and well-suited to their mission.
Perhaps one has to be “of a certain age” to recall Rube Goldberg–his fanciful cartoons employed difficult “solutions” to simple perceived problems. Rube Goldberg seems to be alive and well, and trying to work in the aviation industry.
Compressed hydrogen/fuel cell cars seems to stay at the initial level of non acceptance mostly due to lack of infrastructure, stations to refuel. I think the other drawback is expensive fuel cell technology. If I’m not mistaken, compressed hydrogen stored in well designed carbon fiber tanks have sufficient capacity for range with little weight issues. Perhaps the lighter weight of fuel cells powering a light weight electric motor allows configuring tanks for sufficient range without weight penalties. Initial prototypes of a fc/e-plane Textron/Cessna/ZeroAvia as proof of concept is no small undertaking. It will be interesting if they succeed.
You can probably make this work but there are many problems with hydrogen with one of the main problems being economics with the cost of hydrogen and the fuel cells. I think that the answer for this application will be battery electric but it will not be a conversion of an existing aircraft. Eviation’s Alice just made its first flight with existing lithium ion battery technology. I believe that we will have commercially available lithium sodium batteries within the next 5 years that will have about 3 times the energy density of the current lithium ion batteries. This will make battery electric flight practical for short haul flights up to at least 750 miles but the aircraft will need to be more aerodynamically efficient than a Caravan. Yes, i realize that I will be mocked by some of the more ignorant people commenting on this article.
Energy density of rechargeable Li-Ion batteries is 2.1 MJ/L. Gas is 36 MJ/L. Hydrogen is 5.8 MJ/L … better density than batteries. Also, not affected by cold temps, fast recharge. Fuel cells will power electric motors that are more efficient than gas. All of it is an improvement over batteries. Our arrow can go 600 miles in any direction on 504 lbs of gas. Batteries that could do likewise would weigh far more than the Arrow while h2 despite the limitations you describe could provide 600+ Still, I agree that presently nothing packs the punch of a gallon of gas. This electric stuff gets annoying. Whether cars or planes, batteries fall far short of replacing gas.
Do my degrees from Rutgers College, my doctorate from Rutgers Medical School, or my post doctorate training at Yale University School of Medicine make me ignorant?
Or maybe its my time working for and teaching at Stanford with the Palo Alto Medical Clinic?
Or my multiple leadership and teaching positions at higher academic medical institutions and hospitals?