Comment by chasd00

4 years ago

about cruise missiles, wasn't there one of those DARPA contests to see if a guy in the garage could produce a cruise missile? IIRC it got quite scary and was cancelled or something. Being in the drone and high power rocketry hobby i have absolutely no doubt there's enough knowledge and electronics availability for a guy in their garage to come up with something that delivers 50lbs to a precise gps coordinate a few hundred miles away for less than $10k. Once you do that, it's easy to scale up to 500lbs

I'm skeptical you could hit that sort of range for anywhere near $10K. Forget the electronics, you need an engine powerful enough to lift a few hundred pounds for that distance. Unless you want it detected immediately by early warning radar you need it to fly at a low altitude, like a hundred feet or less. Unless you want it to take forever and be susceptible to infantry with small arms it needs to be traveling fast, in the hundreds of miles an hour. That's simply not possible with an electric system with today's technology, and a rocket engine won't provide the endurance or efficiency you need. That leaves a jet engine or pistol engine. Plus, flying at that speed and altitude means you need an effective autopilot system that uses terrain-following radar. You'll also need some nice guidance packages that allow the shooter to set multiple waypoints, so the missile doesn't have to just fly a direct course. And a 50 lb payload of high explosive just isn't that helpful. There aren't a ton of targets where you only need 50lb of explosives to defeat them, that are also going to stay in the same exact GPS position long enough for your missile to travel a few hundred miles. So you'll want a different terminal guidance method, either some sort of radar sensor or infrared.

I don't think you could get an engine capable of getting you hundreds of miles at that speed and altitude, much less the sensors and guidance system.

  • A lot of the cost in defense contracts is paying for guaranteed domestic supply in the event of a war. If you buy COTS parts and outsource your machining I see $10k as very achievable, the majority of that being metal and explosives. The electronics are nearly trivial, but some of the IR tracking is embargoed and hard to get outside the US.

  • V1 was 160 miles, 1800lb warhead? You saying a bunch of nerds in 2022 can't beat 1940's tech to bring the price down a bit?

    • I think they can bring the price down a bit, but not to $10K, even with a smaller size payload. Also I should mention the V1 was barely accurate enough to target a city the size of London. Not that adding modern GPS guidance would necessarily cost that much, of course.

  • Gliders though.

    • So you use a solid rocket booster or maybe make it air-launched and have it glide to the target? So that is definitely a thing, an example I can think of is the US small diameter bomb (https://en.wikipedia.org/wiki/GBU-53/B_StormBreaker ) or the JSOW (https://en.wikipedia.org/wiki/AGM-154_Joint_Standoff_Weapon ). Though those aren't in the "hundreds of miles" that OP originally proposed, they are in the 50-75 mile range. Those also technically aren't cruise missiles, and don't have the primary advantage of a cruise missile: the ability to travel at low altitudes to evade enemy radars and air defenses.

      That said, you could probably make a glide bomb for pretty cheap. The two examples I gave above are in the hundreds of thousands, but I bet if you sacrificed some of the accuracy and payload, and you were really optimizing for cost, you could get that into the tens of thousands

> wasn't there one of those DARPA contests to see if a guy in the garage could produce a cruise missile? IIRC it got quite scary and was cancelled or something.

This sounds similar to the Nth Country Experiment, conducted by the US in the 1960s. The idea was to see if three freshly minted physics PhDs could design a working nuclear weapon using only publicly available information. In less than 3 years, the three succeeded in creating a credible design for an implosion-style bomb.

https://en.wikipedia.org/wiki/Nth_Country_Experiment