Was expecting the usual story about air traffic control, an F16 and ground speeds, or the one with the flyover way too close to the tower, but this one was new to me. Thanks!
The model in the video look more like an A-12 (earlier CIA version of the SR-71) to me. They flew with bare metal and black leading edges and were single seat.
The YF-12A looked different, the chines didn't extend all the way to the nose and had a ventral fin
Those engines cost more than us$8k each, I hate to think what all the other equipment on board costs. I'd be surprised if the all-up cost for that model was less than ~$25k
I get nervous enough flying my ~us$800 helicopter.
There's only one engine in there. The red glow you see in the mock engine nozzles is produced by LED light rings; which is a really great idea, btw. That really adds to the authenticity. None the less, the actual thrust comes out of the fixed nozzle you see at the center. I'd pin the cost at significantly less than $25k.
EDIT: I just checked, and the cost of a JetCat (a popular R/C turbine vendor) has dropped significantly since I was in to the hobby. Their largest turbine (>50 lbs of thrust) comes in at around $5,500.
I thought the LEDs were a nice touch, and I was a little surprised by their placement, assuming they wouldn't last long exposed to the heat of the exhaust.
On review, I thought the middle exhaust was simulating an APU, which didn't seem quite right, but you appear to be correct, there's only one engine in the middle.
I've seen large, turbine powered scale helicopters sell for more than NZ$20k. That said, helicopters are mechanically more complicated, and they don't look like they're supposed to go mach-3, so they have considerably more exterior detail.
Well, the article is full of other issues too. If you look at the grass behind the plane at the beginning of the video you'll see only one streak of the exhaust, so I'm inclined to believe the GP.
Heh, just a question - could one use e.g. eight of these jet turbines and create something like a fucking-heavy-load octocopter, or is the reaction time of jet turbines too high for this application?
I mean, a single AMT Nike has 800N/80kg of thrust (-11kg for the turbine weight), so eight of these should provide roughly half a ton of load capacity?
No, but not because of the reaction time. Unfortunately jet engines are much less efficient at low speeds like this. They work best when accelerating a large volume of air a little bit, and that means they work poorly in the hover configuration required for an octocopter. Wiki link for the math: http://en.wikipedia.org/wiki/Propulsive_efficiency#Jet_engin...
Larger, slower props are required for maximum efficiency in a hover. The pressure above the prop is never more than one atmosphere, so "suction" is limited unlike when the airplane is flying at a high speed and air is continually forced into the inlet nozzles.
The 800N thrust of those engines is measured at cruising speed, when the only opposing force is drag and the intake and exhaust velocities are very similar. It produces much less thrust starting from zero velocity on the runway, when the opposing force is the inertia of the aircraft.
Jet airplanes, RC electric ducted fans, and jet ski watercraft have similar thrust-vs-velocity response, and are better for their intended purpose as a result - but that doesn't help for octocopters. However, tugboats use a ducted fan for the opposite effect. I am investigating the use of accelerating-configuration ducted fans or "Kort Nozzles" for octocopters.
And yes, the insane reaction time of miniature brushless electric motors is largely what allows these craft to function; you would want variable-pitch props or vectored thrust to make a turbine or internal-combustion craft work well, but that's not the reason they aren't used.
There's nothing preventing one from using a single turbine for lift (or a cluster of them near the center of mass) and some sort of reaction control system (possibly taking bleed air) for stabilization and attitude control.
I've thought about that for a while, didn't actually went as far as doing a feasibility study or actually building the thing.
That's a great model. It has proper nosewheel steering, and can throttle back to taxi speed. They taxi it out to the runway and take off properly. When they land, they taxi back to the parking area. That's much closer to normal aircraft operations than most model aircraft.
That video is from 2012. By now, it would probably have an autopilot and camera.
My Dad is constantly sending me these sorts of videos. The POV ones where you can get camera footage from the plane itself are really amazing. I guess it is cheaper than owning/flying your own plane :-) But I am always impressed at the time and passion these modelers bring to the fly offs.
Add some small arms to something like that and it would be an urban terror. I assume the sole challenge is the ammo would be too heavy, but clearly looking at the future of warfare...
Wow, the pilot sticks the landing. That has to be difficult. The model appears to be moving much faster than a typical R/C plane. If you add the pilot's viewing angle... it must take a lot of practice.
Miniquads FTW.