news2.htm
This page will include progress reports, notes, random brain farts, and other ramblings.
I was sent a copy of great article on an SFRJ. It's titled "Light Rocket Features Solid-Fuel Ramjet," Aviation Week and Space Technology (AW&ST), July 31, 1961, pp 87-90.
This paper describes a Texas company that uses a 2.75 inch solid rocket to boost an SFRJ second stage to about Mach 2. The SFRJ then climbs and accelerates slightly through 70,000 ft. The ramjet stage then coasts to 200,000 ft (flight proven). The system carried a 1.5 lb payload for atmospheric testing.
The ramjet fuel was a magnesium and magnesium-aluminum alloy. The Isp for this propellant is about 700 seconds but the company had plans for one with 1,200 seconds. This compares to the 180-240 typical of current solid fuel rockets.
The company was Anderson, Grenwood & Co., of Houston Texas. The ramjet was designated as the AG-32 Met Jet. If anyone knows anything more about it then please let me know. I've asked for permissiont to print the entire article on this site but don't know if AW&ST will go for it. Many libraries will be able to find the back issue.
The last two months have been busy, mostly with other than the projects.
I've spent a lot of time talking with people and thinking about how best to put on a ramjet conference. It's amazing how many misconceptions and misinformation there is floating around. I've had people tell me that ramjets can't go transonic then be amazed when I tell them NACA did it 50 years ago. For all the interest (mostly commercial and military) there's also a lot of dis-interest. I had one guy tell me to get out of the field and a couple more, whom I thought would be very interested, say they would not attend. This has left me in a quandry as to how best to do this.
I did get one set of testing done. I built a simple X-shaped gutter-type flame holder and stuck it in a 4 inch pipe using the big shop-vac for an air supply and liquid propane for the fuel. The range of fuel/air that would stay lit was not very good.
So I started building a can-type with a conical skirt made out of thin (about .005) cheap stainless. This should have very good characteristics. Unfortunately, trying to weld this thickness of metal is not easy (even the welders at work say it's very hard). Lately I've been playing with my AC welder to try to coax it into being a spot welder. A friend from work is going to buy a small spot welder and we'll both use it. There's a design in the Kamp's model airplane jet engine book but it really doesn't give many details.
Having read where NACA regularly used gasoline and considering the problems of weight and pressure with propane I've decided to start working toward gasoline as the fuel of choice. While shopping for parts to fix up this house I bought some 1/4 inch copper tubing to make a pre-heater for the gasoline.
I'm still trying to figure how to best go about testing my ramjets. This was all so much easier before I started building one. I would like to fly one on a model airplane so I can get some experience with varying speeds and F/A ratios then build up to higher speeds, maybe supersonic. The planes I've seen at the hobby shop won't quite make it. There's a pulsejet-powered delta wing that looks good but it will require a long accelerating run, possibly with bungees. A quick search of the internet found little technical information on bungees or on sellers of what I need.
So, that just about sums up the last couple of months. If it rains tomorrow I may get some more work done on the spot welder and maybe temporarily braze my flame holder. Otherwise it may be next weekend or the following one.
This Page created December 29, 1999
Last Updated Sept 4, 2000