Kaman Aerospace Group has been selected by Transcend Air Corporation to build the Vy 400 high-speed vertical takeoff and landing aircraft.
And yet another short haul electric project materializes. I'm not an aircraft engineer but those engines seem ridiculously small for an aircraft of that size.
In the renderings the rear props are folded while on the ground - makes sense since you don't want to let passengers wander into the sharp bits. However those are referred to as 'cruise props' and the front ones as 'takeoff/climb out', so BOTH sets of props are folding, is my interpretation.“In a normal aircraft, it makes sense to have this quite complex and heavy mechanism on your propeller in order to operate optimally over the whole range,” said Norcia. “Electric propulsion provides some opportunities to just massively simplify the aircraft. So all four of the propellers are fixed-pitch: the ones in front are pitched for takeoff and climb out, and the rear ones are for cruising.”
With a heavy, complex, expensive traditional engine, it would be silly to double the number just so you don’t have to use variable pitch propellers for takeoff. But with light, simple, inexpensive electric engines, it makes perfect sense to do so, even if it looks unusual.
The front and rear propellers are only both active during take-off and climbing, with the front ones folding away afterwards as then the rear ones take over completely for cruise. It mechanically simplifies things — no heavy duty hinges and hydraulics — and in fact putting the prop back there seems to improve efficiency by about 10%, said Norcia. “It’s pretty cool,” he added. (And they’ve applied for a patent.)
You raise a good point about liability. In the U.S. there was an important piece of legislation enacted called GARA that shielded manufacturers like Cessna and Piper from frivolous liability claims and allowed the general aviation sector to roar back to life. I assume somethimg similar could be put in place to help the Evtol sector thrive. Just out of curiosity, does Europe have anythong similar to help protect its smaller GA manufacturers from liability abuse ?And yet another short haul electric project materializes. I'm not an aircraft engineer but those engines seem ridiculously small for an aircraft of that size.
I reckon this as one of the more reasonable proposals although with the usual caveats;- it’s wing aspect ratio gives good cruise performance, while its wing area, combined with flap (Cl max) yields the very low landing speeds (55kts) which is essential for getting into the small strips. Yes the wing mass and turbulence response are both undesirable.The claimed mass fractions don’t look too unrealistic but the performance claims again seem to lack a climb fraction, battery aging fraction, battery operating low temperature fraction, real world considerations such as anti icing etc and again it maybe over reliant on maintaining natural laminar flow.
Yes the motors do look small but assuming they’re axial flux they might not get that much bigger. The prop idea is really novel and technically interesting, but I don’t like the concept of having the pax walking through the prop arc to board the aircraft. Props are real dangerous and Pax can be real dumb….. a combination made safe by a few switches?
One aspect never mentioned by these wannabe companies is the public liability aspect and potential litigation. I once worked with the former chief engineer of BAE Systems Jetstream business and he informed that this market sector was particularly bad compared to others. The basic problem was the operating organisations (airlines and airports) were typically too small/marginal to adequately manage the full range of business and technical risk. Incidents and business failures would routinely spill over to the aircraft provider, who was sued as they represented a very lucrative, indeed the most, cash rich target. The main reason BAESYSTEMS pulled out of the sector was a continuous trading loss coming from legal defence costs. Very few claims against them were successful but they had to pay money out of the business to fight every single one, and there were a lot.
I wonder where the batteries go...under the floor?
It would sound good for the stability. But given the large span wing, maybe in the center wing section. There is also the fact that cabin section is rather minimal when you think that passengers would have to crawl their way forward ro reach their seats.
I wonder if the solution favored by the Tecnam P-Volt that involves mounting the bulk of the batteries in a streamlined belly pod is the best one. I believe that would be the safest location in case of a thermal runaway event. Considering that Tecnam and Rolls Royce have more experience with the certification process than these start ups, maybe that configuration has the best chance of getting approved by regulators. But there would be quite a bit of drag with a belly pod though, so it's a tradeoff between performance and safety.
I think the idea of the pod is to be capable of being released in flight in case of an emergency. If there is a battery fire, the best way to put it down could be to drop it away. Then, either a safety battery take over or a dead stick landing has to be done anyways.
Single engine a/c operating under cs23 have anyway to route plan for crash landing.
Kaman Aerospace Group has been selected by Transcend Air Corporation to build the Vy 400 high-speed vertical takeoff and landing aircraft.verticalmag.com
PSI think the idea of the pod is to be capable of being released in flight in case of an emergency. If there is a battery fire, the best way to put it down could be to drop it away. Then, either a safety battery take over or a dead stick landing has to be done anyways.
Ah no, not certifiable under CS23.1300 where maximum mass that can detach is 0.5kg. Good requirement too as a ton or so, of burning
battery pack coming in at 9.81m/s2 is an unwelcome gift to anyone on the receiving end.
The landing gear with its total absence of wheels is interesting. You have to wonder what's the logic behind such a choice.
REALLY odd. Especially since a tilt-wing configuration gets a very nice payload/range boost if used in STOL mode. This may not be the most frequent use case, but when possible, you could really improve the performance of the vehicle.The landing gear with its total absence of wheels is interesting. You have to wonder what's the logic behind such a choice.
The problem with recovery of a VTOL aircraft via BRS is that BRS systems similar to a Cirrus require forward speed or a drop in altitude of 900-1000 ft to inflate the parachute canopy. Aviation Safety Resources has designed a ballistic chute system that inflates multiple small chutes that require less time to inflate.
Aviation Safety Resources (ASR) designs, tests and produces whole aircraft emergency parachute systems designed to bring down the entire aircraft and its occupants in the event of an in-air-emergencywww.aviationsafetyresources.com
This is true according to the article below. In fact EASA penalizes manufacturers for the inclusion of a BRS system in their designs. EASA's goal is to push manufacturers to devise a means of a "controlled" and "steerable" descent, or essentially a controlled crash in the event of a catastrophic failure. Unfortunately, many of the designs provide no other means of vertical lift to control the rate of decent other than the designs primary powered lift system.According to EASA, a BRS cannot be credited within the certification safety case. They’re classified as survival equipment. If the certification is satisfied, the loss model achieved, it means the BRS is obsolete, and becomes a very costly burden for the operator to carry around (it’s mass displaces a fare paying pax) and maintain.
results are rightly described as "remarkable." The lithium-metal battery with this architecture had an energy density of 560 Wh/kg. For context, there are research consortiums dedicated to breaking through the 500-Wh/kg density threshold in order to power next-generation electric vehicles, while today's best-in-class lithium-ion batteries have energy densities of 250 to 300 Wh/kg.
The Transwing configuration is elegantly simple compared to many other VTOL approaches. On the question of the high loads on the wing pivot hinges and mechanism, that is certainly a challenge but not one I think is that is technically challenging to overcome in my opinion.
This makes me wonder if sodium batteries could be amenable to a similar chemistry and enable cheaper high power density than lithium.results are rightly described as "remarkable." The lithium-metal battery with this architecture had an energy density of 560 Wh/kg. For context, there are research consortiums dedicated to breaking through the 500-Wh/kg density threshold in order to power next-generation electric vehicles, while today's best-in-class lithium-ion batteries have energy densities of 250 to 300 Wh/kg.
For electric planes to really take off and for electric cars to travel far longer distances between charges, we'll need batteries that pack far more energy without becoming prohibitively heavy. A team in Germany has now demonstrated a new lithium-metal battery with a density well beyond the…newatlas.com
This makes me wonder if sodium batteries could be amenable to a similar chemistry and enable cheaper high power density than lithium.