It’s a bit of a grey area honestly. I believe I saw that this UAV can carry a 10kg payload. In contrast to Storm Shadow/SCALP EG, which delivers a 450kg dual stage warhead, it’s hard to classify this directly as a “cruise missile”. It’s possible that there will eventually be a settled terminology for this classification of range and payload that makes more sense, since the use case and application are very different than traditional cruise missiles.
I expect cruise missiles to get a guided mode in the future. But indeed the size and payload will depends. I very much see a hull that could make for either regular cruise missile or guided drone.
I wonder what the design decision was for the forward-swept wings. These typically decrease lateral stability and increase structural weight, because they require substantially higher stiffness for flutter-resistance compared to straight or rear-swept wings. Maybe so the main wing spar can be further aft to have a larger contiguous payload bay. The HansaJet had forward-swept wings for a similar reason (no main spar in the cabin).
I would think it’s got to do with spanwise flow. The forward swept design brings the spanwise flow toward the fuselage and allows for more effective control of the ailerons when traveling at transonic speeds like can be expected from a “drone/missile/UAV” like this.
It also allows for a reduction in vortices formed by the wingtip which would increase drag and decrease efficiency. That means you can get away with a smaller wing, decreasing weight and either increasing your payload or maximum range.
If it were beneficial in total, most transonic planes would have it. The only aerodynamic advantage over backward swept wings is higher manoeuvrability, which isn’t a priority here. This isn’t a dogfighter. My money is still on better payload distribution.
more effective control of the ailerons
Not sure what that means. I don’t think agility is a priority with a jet-powered drone. Or benign stall characteristics.
reduction in vortices formed by the wingtip which would increase drag and decrease efficiency
That is negligible. We know how to reduce wingtip vortices, and reverse sweep is not the answer. Raked wingtips as used on the 787 and the larger-wing versions of the 777 and the 777X are optimal for transonic flight. Blended winglets are a close second, as used on the A350 and A330neo. Again, not forward sweep.
This thing also does not look very refined aerodynamically, and there are many more things that could be done to reduce drag that are much cheaper. Wing-body fairings come to mind to reduce interference drag, or winglets if you really want to go there. This has all the looks of “Eh. Good enough. Send it!”, which makes sense given the urgency.
I think they don’t have at their disposal a proper aerodynamic tube. Perhaps you would kindly recommend some software to model the aerodynamic properties?
That’s the point. This is not a very refined design, it is a quick-and-dirty, “good enough” approach to get it out of the door as quickly as possible while still fulfilling the requirements. Which is why I found it surprising that forward sweep was deemed the best option, despite its aerodynamic and structural challenges (which usually outweigh any benefits). And as I said, fuel efficiency was not foremost on the designers’ minds. Case in point: small turbojets are notoriously inefficient (only pulsejets and rockets are worse), and many small details could be improved cheaply. But having a large unobstructed payload bay is a very good reason for forward-swept wings on such a small design and can greatly simplify operation. I will not recommend any computational fluid dynamics package, because it takes many years of study and experience to apply it to real-world problems meaningfully. And if the design team includes aerodynamicists, they will know what software to use anyway, and don’t need my recommendation. Surprisingly, if you have good data on the airfoil cross-section performance, X-Plane is not the worst tool to get a good idea of performance and stability. It was used for Solar Impulse in that way (also for pilot training).
This is an ECM/reconnaissance drone, not a cruise missile. So no “target” in the normal sense (although I wouldn’t be surprised if it was going to be used a cruise missile, too). And reduction of induced drag (raked wingtips or winglets for transonic; straight high aspect-ratio wings with elliptic lift distribution for subsonic) works the same at both scales. At a cruise speed of 600 km/h this is fast, but almost certainly fully subsonic, so sweep makes little sense aerodynamically, in either direction. If they were bothered about fuel efficiency, it would have long, straight, high-aspect-ratio wings, like the Global Hawk, or the Reaper, or the Predator, and a turbofan or turboprop engine.
I’m sure they’re no idiots and have very good reasons for the design decision. I just doubt that the reason is aerodynamic efficiency.
The beaver cruise missile is completely different, it is a propeller-driven canard with straight wings. But that may actually be the reason: they re-used the fuselage design, and with the same wing attachment point, forward sweep was required to maintain a reasonable centre of lift in a conventional configuration. Again: a compromise for a short time to deployment. Not aerodynamic refinement.
Only if it’s meant for a single one-way flight that ends with a big kaboom. Presumably since they’re calling it a drone it’s meant to fly somewhere, do something (deliver ordnance or just surveil an area) and come back for refueling, repairs, and redeployment.
I think the difference between this and a regular cruise missile is that this has manual control and can be more than just a explosive payload delivery system. A cruise missile usually has an assigned target that when fired it will fly to and hit, this can do more complex things like reconissaince.
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