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Post by azwood on Mar 9, 2018 6:13:32 GMT -5
Yeah no worries mate, I have Tues off as well. Cheers, Mark. What do you do for work it just seems you build a lot of projects how do you find time |
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Post by pitciblackscotland on Mar 9, 2018 7:12:28 GMT -5
I work as a operating theatre technician, use to be a fitter and turner a while ago. LOL you just make the time,some projects i work at it for a couple of hours a day or sometimes all day.
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Post by azwood on Mar 12, 2018 20:54:22 GMT -5
Been looking at the st50 build I like how compact it is
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Post by azwood on Mar 13, 2018 4:46:55 GMT -5
As suggested I will use lpg to start with before trying jet a fuel found this high pressure washer nozzle laying around the spray flows backwards in a real nice mist hope to use it for lpg I'll see how it goes I guess  |
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Post by azwood on Mar 13, 2018 4:49:42 GMT -5
I tig welded it onto a thick wall tube the holes are tiny maybe .50mm I can open them up if I need to
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Post by azwood on Mar 13, 2018 5:58:46 GMT -5
Been in the shed marking some more progress with the ft tonight I have just talked to exit cone on it will get cut off to sand off any drill swarf from the holes  |
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Post by azwood on Mar 13, 2018 17:34:51 GMT -5
Still can't get the jet specs app to work would anyone be kind enough to give me some hole sizes nuber and locations for a 82mm inducer
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Post by azwood on Mar 13, 2018 17:36:49 GMT -5
Sorry inducer 100mm wheel 95mm turbine 88mm exducer 140mm ft
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Post by azwood on Mar 13, 2018 17:38:09 GMT -5
Sorry inducer 100mm wheel 95mm turbine 88mm exducer 140mm ft So it's a 82 inducer and 100mm compressor wheel to be clear |
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Post by azwood on Mar 13, 2018 19:46:44 GMT -5
Ok so a calculator inline said my 82mm inducer is 52.81 scm so primery holes 15.843scm secondary 10.562scm and sustain holes 26.405scm lol but I have no idear how to break that down into drill sizes.
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Post by racket on Mar 13, 2018 22:15:58 GMT -5
Hi
OK , 5280 sq mms inducer area , 30% for Primary is 1585 sq mms , if you only intend to have a single row of holes , then you need them where a fuel spray would theoretically impact the wall , or if using vapouriser , where the outlets of them are and some others inbetween to produce turbulence , but we'll concentrate of a single row of 10 holes using 2/3rds of that 30% , the other 1/3rd for wall cooling/other things , so 1585/3 X 2 = 1056 sq mms , divide by our 10 holes = 105.6 sq mms per hole, divide by Pi = 33.6.45, square root = 5.8 mm radius , so 10 X 11.6 mm dia holes required .
The other 1/3rd or 528 sq mms would normally be used in the flametube cap , some for swirl vanes surrounding the fuel spray nozzle and some for holes in the cap to keep it cool by keeping flames away from it .
The Secondary holes at roughly mid point down the flametube will have a total of 1056 sq mms , but lets go for 15 holes as they don't need to penetrate as deep, so 70.4 sq mms/hole , div by Pi = 22.4 , sq root = 4.7 , so 15 X 9.4 mm dia holes , these can again be smaller if some of that 1056 sq mms is allotted to a row of small 2mm dia wall cooling between the Primary and Secondary rows , 2mm dia holes are roughly 3 sq mms a piece so if theres say 30 of them around the flametube we use up only ~100 sq mms , this would then bring our 15 main Secondary holes back to 63.7 sq mms each or 9 mm dia .
The Tertiary holes at the lower parts of the flametube have 2640 sq mms to be divided amongst them , so if you have 10 holes at 264 sq mms each , or 18.3 mm dia
Hope this helps
Cheers
John
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CH3NO2
Senior Member
Joined: March 2017
Posts: 455 
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Post by CH3NO2 on Mar 13, 2018 22:28:55 GMT -5
Thats a good question.
I dont have a clue on how to guess a specific diameter but maybe we can get some context on the sizing.
You need 15.843scm dedicated to the primary zone. We know this from Jetspecs.
We can't know the size of each hole but we can guess a reasonable number of holes we may typically want in the primary zone. In the range of 8 to 16 main radial jets (excluding the boundary layer cooling holes). Divide the primary area by the number of holes you think you may need. Then with the area per hole, back out the diameter.
If you (hypothetically) want to use 12 main radial jets on your primary zone, divide the primary area by 12.
15.843scm total/12holes = 1.32scm/hole = 1.29mm diameter.
PS - Never mind. As I was writing this John already replied with a much better answer.
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Post by azwood on Mar 14, 2018 4:40:44 GMT -5
Hi OK , 5280 sq mms inducer area , 30% for Primary is 1585 sq mms , if you only intend to have a single row of holes , then you need them where a fuel spray would theoretically impact the wall , or if using vapouriser , where the outlets of them are and some others inbetween to produce turbulence , but we'll concentrate of a single row of 10 holes using 2/3rds of that 30% , the other 1/3rd for wall cooling/other things , so 1585/3 X 2 = 1056 sq mms , divide by our 10 holes = 105.6 sq mms per hole, divide by Pi = 33.6.45, square root = 5.8 mm radius , so 10 X 11.6 mm dia holes required . The other 1/3rd or 528 sq mms would normally be used in the flametube cap , some for swirl vanes surrounding the fuel spray nozzle and some for holes in the cap to keep it cool by keeping flames away from it . The Secondary holes at roughly mid point down the flametube will have a total of 1056 sq mms , but lets go for 15 holes as they don't need to penetrate as deep, so 70.4 sq mms/hole , div by Pi = 22.4 , sq root = 4.7 , so 15 X 9.4 mm dia holes , these can again be smaller is some of that 1056 sq mms is allotted to a row of small 2mm dia wall cooling between the Primary and Secondary rows , 2mm dia holes are roughly 3 sq mms a piece so if theres say 30 of them around the flametube we use up only ~100 sq mms , this would then bring our 15 main Secondary holes back to 63.7 sq mms each or 9 mm dia . The Tertiary holes at the lower parts of the flametube have 2640 sq mms to be divided amongst them , so if you have 10 holes at 264 sq mms each , or 18.3 mm dia Hope this helps Cheers John Thanks your a legend mate at least I know I will be done Wright now. |
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Post by azwood on Mar 14, 2018 4:42:28 GMT -5
Thats a good question. I dont have a clue on how to guess a specific diameter but maybe we can get some context on the sizing. You need 15.843scm dedicated to the primary zone. We know this from Jetspecs. We can't know the size of each hole but we can guess a reasonable number of holes we may typically want in the primary zone. In the range of 8 to 16 main radial jets (excluding the boundary layer cooling holes). Divide the primary area by the number of holes you think you may need. Then with the area per hole, back out the diameter. If you (hypothetically) want to use 12 main radial jets on your primary zone, divide the primary area by 12. 15.843scm total/12holes = 1.32scm/hole = 1.29mm diameter. PS - Never mind. As I was writing this John already replied with a much better answer. Thanks for takeing the time to reply |
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Post by smithy1 on Mar 14, 2018 19:47:33 GMT -5
15.843scm total/12holes = 1.32scm/hole = 1.29mm diameter. Tony....You've been drinking again haven't you..??   Smithy |
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