stevejet66 Posted July 15, 2013 Share Posted July 15, 2013 My kj66 is 75% homebuilt with the exception of the compressor, ngv and turbine wheel, Anyone wanting to build one can do so on a budget, I do not use a fadec because of the cost, They are not complicated neither is it difficult to managed the engine control within safe parameters. Its just so easy to buy of the shelf turbines, But such an achievement to build your own. I may be doing a static display at the LMA cosford on sunday just waiting for the invitation, Come have a chat and take a look. Heres my website, Hope it encourages some to get building! **LINK** Quote Link to comment Share on other sites More sharing options...
Dave Cooper 3 Posted October 14, 2018 Share Posted October 14, 2018 Steve Is your website coming back soon ? I couldn't get your above link to work ! Would love to see some more on this as it's my ambition (long-term) to build a turbine-powered Jet Provost and the commercial offerings are just so expensive... Down at the Thornbury Model Engineering Show (North Bristol) this year there was a guy who had built his own rig for dynamic balancing of the rotating parts. He said anyone who is building his own turbine could contact him for a possible loan /test. This could be the most difficult part for me ! Regards, Dave Quote Link to comment Share on other sites More sharing options...
SR 71 Posted October 14, 2018 Share Posted October 14, 2018 The page is not available to me either, im also interested in home built, i fly turbines now, Quote Link to comment Share on other sites More sharing options...
stevejet66 Posted October 14, 2018 Author Share Posted October 14, 2018 Hi guys, Im afraid i had to abandon the website, From what turned out to be a fun project (which it still is to me and should be for anyone) Became a bit of a nightmare. I didnt expect the attraction that i had anticipated, I was getting endless emails from around the world, Mainly turkey, Russia, Romania, Greece, Saudi arabia, Unites states, I just couldnt keep up with them, It even flowed on to my facebook page via PMing having to eventually block them. Amazing what a website can attract. If i can try and help i dont mind but please take into consideration that some degree of engineering skill is required for home build and endless hours perfecting the final results so its quite a task. Not forgetting todays modern turbines are all cnc machined plus all the software that is needed to operate them, Hence the cost! Quote Link to comment Share on other sites More sharing options...
Dave Cooper 3 Posted October 14, 2018 Share Posted October 14, 2018 Hi Steve, Many thanks for the update, and, I quite understand your predicament... For the time being, I would be happy to have some basic design parameters to feed into my model project. If you are OK with this, could you give some guidance on the following :- 1. Realistic target thrust for a DIY build with non-CNC machining. (I can do most manual machining) 2. Are there circuit diagrams available for the FADEC (I'm reasonably competent with soldering /bread-boarding / component installation - but not surface mount ! Also, testing / fault-finding). 3. What sort of jet-pipe temperatures can be expected at full thrust. Is 'Stainless' likely to be ok for material or do I need to go 'exotic' - Inconel etc. 4. If you have any flying experience with turbines, what sort of Fail-safe's would I need to consider - fuel cut-off, JPT limits exceeded etc. (SR 71 can you help here please ?) Thanks for you patience with this ! Dave Quote Link to comment Share on other sites More sharing options...
stevejet66 Posted October 15, 2018 Author Share Posted October 15, 2018 1. Realistic target thrust for a DIY build with non-CNC machining. (I can do most manual machining) Answer: My realistic thrust target was aimed at 12lb, However this depends not so much on rpm but ensuring the the inner and outer exhaust nozzle is the correct shape and size, This was made by making a plug and the inner cone was pressed over the plug via an outer ring to form the shape. Thrust is now 16Lb. 2. Are there circuit diagrams available for the FADEC (I'm reasonably competent with soldering /bread-boarding / component installation - but not surface mount ! Also, testing / fault-finding). Answer: There are circuit diagrams but would take for ever and a day to build, These were about 10 years ago or so ide be very surprised if components were still available plus you would need a chip programmer and other software to configure exactly what you want your Hombuild fadec to do My thoughts are its not even worth the paper its wrote on. I dont use fadec, My throttle control is programmed on the helicopter throttle curve on my spektrum DX7 and a fuel expansion tank for precise throttling. 3. What sort of jet-pipe temperatures can be expected at full thrust. Is 'Stainless' likely to be ok for material or do I need to go 'exotic' - Inconel etc. Answer: At full throttle my turbine runs at a cool 525 degrees centigrade, Thats cool! I use an inconel turbine and NGV and stainless combustion chamber. 4. If you have any flying experience with turbines, what sort of Fail-safe's would I need to consider - fuel cut-off, JPT limits exceeded etc. (SR 71 can you help here please ?) Answer: ive only flew it once, But regarding saftey i have micro switches operated by mini servos and saftey shut off valve for fuel, Again operated by servo all programmed on my DX7. This enables the fuel pump to be switched off and fuel shut down as another back up. Hope this helps dave, There many other factors to, You would also need to work out how you would monitor the rotational speed of your turbine, I had no way or devise to help me with this so i had to work out what was the rotational speed by the amount of thrust it produces quite simply by using kitcken scales, A simple enough task but only one would be a fool to be as excited to see your turbine kicking out 20Lbs or so of thrust when its probably on the verge of distruction, Keeping within parameters is absolute. Quote Link to comment Share on other sites More sharing options...
Dave Cooper 3 Posted October 15, 2018 Share Posted October 15, 2018 Thanks for the comprehensive reply Steve - that really helps....I forgot to mention 'ceramic' bearings and any special lubrication needs ? For the rotational speed, you could try contacting the "Gas Turbine Builders Association". I don't think they have a website yet but seem very knowledgeable about model turbine design and development. I have a contact name and email : James V.G Hill, [email protected] Best regards for now, Dave Quote Link to comment Share on other sites More sharing options...
stevejet66 Posted October 15, 2018 Author Share Posted October 15, 2018 Dave there are plenty of places that supply ceramic bearing but be very carefull as not to get ripped off, One well known manufacture in the uk wanted 100 pounds for two bearings, Got mine online for 35 pounds the pair, As far as the gas turbine builders association are concern you may as well try filling a bucket up without a bottom in mate because youll get more out of it., The association was more for there own benefit than anyone elses. Quote Link to comment Share on other sites More sharing options...
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