Hello, haven't been active for a while. I'm interested in technical details of the J. guided missiles projects during WW2. I know about the Funryu project from this site ( Funryu (Raging Dragon) SAM ), but I find the info there a bit confusing. As I understand the version 4 had dual radio and radar guiding, but what about the others? How big should be the warhead to house the guidance systems with the technology of the time? If you have some info you are welcome to contribute.
Hi. There is some info about the guidance system and the position of the electronic equipment inside the radio-controlled Ki-148 (I-Go B) guided bomb at the US NAVAL TECHNICAL MISSION TO JAPAN report O-02. Converted TIFFs (archive.org) The Funryu used a similar system so the infos can be somewhat usefull. Yours tom!
Japan wasn't going to get far with any sort of guidance system not for lack of inventiveness, but rather for lack of any way to take the theoretical and produce a physical result. In 1945 they had school children cutting copper tubing to make dipoles for radar. Their electronics industry was miniscule in size compared to Germany, Britain, the US, or even the Netherlands (Dutch Philips Company)--where surprisingly Germany was getting about a third of their vacuum tubes. Anyway, Japan simply didn't have the research or production facilities and personnel to pursue something like a SAM to viability. As for a warhead, given the lack of a proximity fuze, the poor level of guidance any system they developed would have had, I'd say to ensure a command detonated weapon would get a reasonable level of kill probability you'd need a 500 to 1000 lbs. warhead.
Yes, of course, Japan had trouble building even more conventional weapons in useful numbers. But I was interested in the technical specifications and the theoretical potentials of those systems. Apparently they had developed the concept of radar beam riding, which was quite viable at least in theory for a short range AA missile. I wonder how much place the guidance system took in the warhead. Am I correct that Japan didn't develop the same miniaturization of electronics capability that the Western Allies possessed thanks to their advanced cavity magnetron? Funryu 4 had a 200 kg warhead, so it may have been quite effective.
Actually, the Japanese beat everybody to developing a workable cavity magnetron. Theirs wasn't as powerful as the one the British came up with but it worked. It took Japan nearly three years however to turn that into a working radar set that could be mass produced so they didn't have sets deployed until late 1944. While Japan didn't make miniaturized vacuum tubes and such like the Allies did, they were on par, at least in terms of engineering on most areas of electronics. They simply had no way to produce more than one-offs or a few sets of something. For most of the war, Japan ran two parallel electronics programs, one army, one navy, and the two didn't share much if anything on their developments and research. The total employment in these was around a thousand people total making their programs miniscule in size. It didn't help that the army in particular would syphon off men from their program for combat service. As for a guidance system, beam riding was the early go-to for many SAM programs. It was the British choice for Brakemine and Stooge, the German choice for Wasserfall, Rhinetochter, and Ezinan, and for the US Little Joe, Lark, Nike, and GAPA programs (at least initially). The biggest issues with early SAM's were: Subsonic was found unacceptable. Such missiles were simply too slow to get the job done. Lack of supersonic data made building and controlling such a missile difficult to impossible to accomplish Beam riding guidance was ineffective on maneuvering targets Controlling the missile in flight was a huge issue that took a lot of development effort to get to work properly. Of the early SAM programs, the stand-out one that really was on the right track to a good system was Project Bumblebee in the US. It was more advanced in most ways in 1945 than any other SAM project anybody was working on. That program by early 1945 was firing (unguided) missiles at Mach 1.5+ to 12+ miles and 30,000 + feet that worked. There was a parallel program in progress to develop supersonic flight controls that worked, along with a guidance system that would maximize range and accuracy.
Thanks for the interesting info bro. Do you have more information and sources on the Japanese cavity magnetron and on Project Bumblebee? I thought that the first missile from that project was tested in October 1945. Good to see that some fancy new weapon wasn't German for a change I just read The German Way of War by Jaap Jan Brouwer, and according to him it would seem that the Germans did everything right and all the others couldn't tell t*t from a**, if you pardon my French... Maybe I'll make a new thread with a review of that book BTW.
A baisc starter (though I feel uncleran posting Wiki) Yoji Ito - Wikipedia Japanese radar is an area I know precisly nothing about, beyond what I have googled just now
There isn't a lot on Bumblebee as a whole program. I'm currently researching and doing a book on early SAM systems (1940 to 1955). As for the Japanese cavity magnetron, there's an article in Radar Development to 1945 Russell Burns ed., entitled The History of Japanese Radar Development to 1945 by Dr. S. Nakajima. Their first one was the M2, also called the Mandrin or Tachibana type developed in 1937. It operated at 20 cm. The M3 of 1939, operated at 10 cm. The M3 was used in the development of Japanese millimeter radar but only really became a serious research item after May 1941 when Japanese military officers saw German radar sets in use. That's the 2 shi 2 go (or No. 22) radar set that operates at 10 cm. It started going on ships in early 1944.
I've lost my bookmark that GRW provided a few Years ago that had a very good article on the US early cruise missile programs. My uncle was stationed in White Sands mid 1950's and they would launch from there send a missile to near Wendover Nevada, have it turn around and fly back over the base. Only thing that could 'almost' keep up was a F100. Radio and camera following map was used then. With beacons stationed along the route I think. Blow off the wing as it neared the area of the base and helo' out to pick up the leftovers.
I just dug up the PDF I had buried in my bookmarks. Google : "The Evolution of The Cruise Missile" by Kenneth P. Werrel. The photos leave a little to be desired by it has some interesting reading.
I got an interesting book, which I had only time to skim through so far: Japanese Secret Projects. Experimental Aircraft of the IJA and IJN 1939-1945 by E.M. Dyer. Lots of technical info and beautiful drawings about a bunch of strange aircraft, some of which I had never heard about. As I said I haven't had time to read it thoroughly yet but I'd recommend it to any of you guys interested in Japanese mil. tech from WW2.
That would be the USAF's Mace and then Matador (SM 61A)--Mostly Matador missiles. Those launches occurred from the test range at Holloman AFB rather than the US Army's WSMR. Most flights were one-way however. The follow-on Snark SM 62 was tested almost totally at Cape Canaveral Florida as the range had increased from hundreds of miles to close to 1000 as these missiles were intended at intercontinental cruise missiles at the time.
Air Vectors also has a very good overview of US cruise missiles. US Cruise Missiles Also Drones, missiles, and various smart weapons. AirVectors: Weapons
After posting my last entry I started to read Japanese Secret Projects and I found that at the end there is a section about missiles, which basically answer my OP questions. I made a JPG of the relevant pages and I'm attaching it here.
