What is necessary for a hypothetical supersonic speed Radio Controlled Jet?

[kalabren]

You can probably buy an old Mig-31 from somewhere. They're reliable, still in service, and super fast. Similar role to the F-104 but newer design.

 

[Baluncore]

A rifle can launch a missile that exceeds the speed of sound. You will need to make a very small radio control receiver to steer the spinning bullet. There are gyros that will easily fit with the receiver inside a round. The very small control surfaces on the spinning bullet will need to operate at above 1 kHz.

 

[jrmichler]

Summary:: What its the necessary elements for a Radio Control Jet?

Im very corious about if this its possible to do and achieve the sonic boom.

To summarize the thread so far: It is possible, but...

1) You need to design and build an airframe that is controllable over the full speed range
and
2) Is strong enough to withstand the aerodynamic forces
and
3) Low drag at supersonic speeds
and
4) Takeoff and landing speeds low enough to be able to use existing runways
and
5) A semi or fully autonomous control system
and
6) Get permission from the FAA
and
7) Design and build a jet engine capable of supersonic operation
and
8) A suitable telemetry system with pilot interface (think glass cockpit)
and
9) A few things I did not think of yet.

The effort required is years, not weeks or months, for each of the above items. That explains why nobody has done it yet. Also, high speed flight has considerations that are not necessarily obvious. For example, a 2 G turn at 1000 ft/sec will make a circle about 6 miles diameter.

 

[DaveC426913]

"...a 2 G turn at 1000 ft/sec will make a circle about 6 miles diameter"

Uh huh, and what is that reduced to at >12g's?

Spoiler: Hint

<1 mile

 

[cjl]

Point-of-order: I am greatly concerned about the discussion potentially veering into ways to design and engineer what amounts to a remote-controlled missile. A 20 pound object being consciously directed at 1000mph into a target can do a lot of damage.

I see it as no different from discussing how one might make explosives or toxins - i.e.: As long as readers obey the law, there's no harm - and yet - it's still it's arming and informing those who wish to do harm. The PF I know and love frowns on that.

Just my 2c.

Honestly, the way I view it, anyone with the technical ability to make this actually happen won't have that much difficulty figuring out how. This is well beyond just assembling commercially available parts here, even with all the information provided above.

As I said, a significant amount of what I know about it comes from a former professor of mine working with a team of aerospace graduate students and a decent amount of funding, and though I'm confident we came up with a viable concept for a mach 1.4 drone based on commercially available parts, it took a huge amount of time and still involved a lot of custom work to get it (hopefully) functional, and as far as I know, it never actually turned into real flight hardware.

To me, this is very different from something like an explosives discussion, where it genuinely is plausible for someone with little experience to make something that at least is fairly dangerous by themselves without a lot of additional resources. To make a working supersonic UAV, you'd be talking tens of thousands of dollars and hundreds or thousands of hours of design and fabrication work, and that's assuming you know what you're doing.

 

[Rive]

Uh huh, and what is that reduced to at >12g's?

12g for a DIY custom drone? The question would be about the debris distribution, right?

You can probably buy an old Mig-31 from somewhere.

Sure. Though a Mig-21 would be a better choice, and it's dirt cheap.
But, to actually fly it (to keep it in flying order) would take lot more than just the bird, you know...

 

[DaveC426913]

12g for a DIY custom drone?

Premise already established that it will hold together at Mach 1+. So not a stretch.

 

[kalabren]

A rifle can launch a missile that exceeds the speed of sound. You will need to make a very small radio control receiver to steer the spinning bullet. There are gyros that will easily fit with the receiver inside a round. The very small control surfaces on the spinning bullet will need to operate at above 1 kHz.

Guided smallarms rounds do exist. As far as I am aware, the USA and the PRC both have one, though they are too expensive and temperamental to use operationally.

I don't know any technical specifications of the rounds, in particular whether or not they spin if they have control surfaces.

You can probably buy an old MANPADS (the shoulder anti-air missiles) for USD 300 and a goat. If you were trying to be super bad, that's probably much easier that building your own missile. As such, I don't see any inherent danger in this thread.

 

[Astronuc]

1) You need to design and build an airframe that is controllable over the full speed range
and
2) Is strong enough to withstand the aerodynamic forces
and
3) Low drag at supersonic speeds
and
4) Takeoff and landing speeds low enough to be able to use existing runways
and
5) A semi or fully autonomous control system
and
6) Get permission from the FAA
and
7) Design and build a jet engine capable of supersonic operation
and
8) A suitable telemetry system with pilot interface (think glass cockpit)
and

I like jrmichler's response, but I would put the FAA at the top of the list, since they regulate what goes up into the atmosphere, especially aircraft.

https://www.physicsforums.com/threa...eed-radio-controlled-jet.1007617/post-6580673

https://www.faa.gov/newsroom/supersonic-flight
Currently, U.S. law prohibits flight in excess of Mach 1 over land unless specifically authorized by the FAA for purposes stated in the regulations. The two supersonic rulemaking activities would not rescind the prohibition of flight in excess of Mach 1 over land.

Unmanned Aircraft Systems (UAS)
https://www.faa.gov/uas/
https://www.faa.gov/newsroom/small-unmanned-aircraft-systems-uas-regulations-part-107 (probably precludes supersonic UAS, or small UASs). I would imagine that if one obtain permission, one would have to test/fly such an aircraft in restricted airspace, similar to that for small spacecraft /rocket launches.

Some rules concerning drones/UAVs

Operating Requirements
Just as there are rules of the road when driving a car, there are rules of the sky when operating a drone.

• Always avoid manned aircraft.
• Never operate in a careless or reckless manner.
• Keep your drone within sight. If you use First Person View or similar technology, you must have a visual observer always keep your drone within unaided sight (for example, no binoculars).
• You cannot be a pilot or visual observer for more than one drone operation at a time.
• Do not fly a drone over people unless they are directly participating in the operation.
• Do not operate your drone from a moving vehicle or aircraft unless you are flying your drone over a sparsely populated area and it does not involve the transportation of property for compensation or hire.

Recreational Flyers & Modeler Community-Based Organizations
https://www.faa.gov/uas/recreational_fliers/

There may not be a rule for supersonic UAVs, since nobody does that - yet. Yes, US, Russia, China, and others, are looking a hypersonic aircraft/missiles obviously with military applications, which is why it may not be legal for supersonic drones (UAVs).

Technically, one only needs a propulsion system that can push such a craft through the atmosphere, meaning the thrust must equal drag at the designed supersonic speed. The rest (aircraft geometric design, flight control surfaces, strength of materials (structural integrity), . . . is pretty straightforward.

 

[berkeman]

Okay, I think the question in the OP has been answered pretty well, including practical considerations for how to keep track of such a fast RC aircraft/drone. Since we are heading into discussions about SA-7 missiles and goats, it's probably best to tie off the thread now. Thanks everybody for an interesting discussion.