Larry's geared turbofan jet engine.

The free turbine turns 60K RPM. The planetary gears reduce it to 14K RPM.

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Geared-fan technology is being further developed and refined by major manufactures like Pratt & Whitney. I actually received an email from a member of the team working on it! He said someone printed out my page here and it's hanging on the wall in the lab. He said everyone gets a kick out of it.

Where am I going to find a 14 (or 15 or 16) inch diameter fan that can turn 14,000 RPM? Where? Ha! Here's one on eBay! Oh no! Someone made a wall clock out of it! Argh! Rats --- I would have bought it anyway EXCEPT the thing was bid up to over $250.00!!! GE said (in a TV ad) they wish they could have helped Orvil & Wilbur, ha, Hey GE, what about me? All I want is 300 pounds static thrust and would settle for 200. My turbine engine is producting only about 50-60 HP. I saw 300 pounds thrust with a 68" 3 bladed prop, and 310 pounds with a 72" 3 blade prop (IVO 372). With 500 pounds I could fly 100% vertical. There are new engines being developed for new little business jets that have fans just like what I need. Like the Eclipse 500 that will cost only $1,000,000.00. It has two little fanjet engines. The fan is just the right size - about 14 inch diameter. My 20-to-1 gear box outputs 3,000 rpm. If I remove one gear, I can tap-out 14,000 rpm. This is my spare engine. I assembled it from boxes of parts and flew it a few times before changing over to the professionally assembled (and wired) one. We tore this one down to check the bearings - and all looks good. I'm modifying it a lot to reduce weight and simplify the fuel and throttle system. I'm thinking a 14 inch is a good diameter because turning at 14,000 rpm it will have a tip velocity of about 1,000 fps which is about supersonic. The number 7 seems good. I get 7 miles to the gallon, and I burn 7 gallons per hour. So a radius of 7 inches looks just dandy. I read somewhere that having a stator would be good. I found a couple on eBay for $15 each. They are 15 inches across -- just right. The fan will need lots of blades, maybe 100 or more?: These blades are 0.9 inches wide and 2.7 inches long. They have a nice twist and weigh 0.05 pounds each. I found the formula for centripetal force on the internet: Fc = (mass * velocity **2) / radius. So if I did my arithmatic right, the blades will "weigh" about 50,000 times as much? These cost me $1.00 each on eBay. I think I have about 120 or more, I hope enough. I don't know what the blades are from. Here's one with some numbers on it. It would be very cool to find a hub that holds these. I found this hub here on eBay for $20 It's the right diameter but the wrong slots. AND it's what they call "de-Milled" or something like that. They actually destroy it by cutting it so no one can use it for it's intended purpose. (thanks a lot guys!) So once again I have to make it myself - reinventing wheels is not helping this project. Why can't I just buy one at a local jet junk yard? A blade weighs 1/20th of a pound standing still. But when it's being pulled around in a 7 inch radius circle at 600 miles per hour, it will pull away from the center with a centripetal force 50,000 times more, which is 2,500 pounds per blade! So I need to make a machine that will pull that much so I can test the hub I make and the materials I use. In this photo is a 1 inch thick chunk of 6061 aluminum which I drilled some holes the blade fits into. Next I need to test if it will hold. Here is the engine I've been flying with a propeller. I placed the large round part on there to get an idea of what it may look like with a fan. It will be a pusher turbofan. And I'll probably need a "duct" for the fan. On the left is the oil tank and oil cooler ($22 in the auto parts store, new!) This engine starts easy, runs real smooth, and sounds totally awesome.     One last photo. Williams International has designed an engine with a 14 inch FAN for the new Eclipse 500 business jet but lost the deal to Pratt & Whitney's larger engine. I wrote Williams, they were very nice to me and said they will continue to develope the FJ22 engine technology, however they cannot help me because of "litigation issues related to experimental aircraft" and other things. GE blew me off with a form letter. I sold my shares of GE at $31 and bought BA (Boeing) at $42. Boeing it a real aircraft company - and they bought my old employeer McDonnell Douglas. NOTICE: (update 11/2006 - 2 years later) GE stock is up from $31 to $35, but the Boeing I bought at $42 is now $86 !!!MORE THAN DOUBLE!!!!!!!! 6-Jan-04: My trip to pick up turbine engine part with Jack Rogan - can't be worse than BarneyCam, can it? IPO: Sunday, 4-January-2004 My home page. See my other crazy projects. About 2000 page views from Jan04 to Jan05, wow, not much considering all of Pfranc.com has over 2600 visitors and over 7500 page views PER DAY!