KJ66 Conversies

Toch een magisch ontwerp wat die Kurt en Jesus gemaakt hebben in de jaren 90.
Begon volgens Wikipedia met 7 kilo stuwdruk. En nu ben je bezig er het 3x zoveel uit te krijgen.

Succes met de bouw. En maak het ons alsjeblieft lekker, door veel foto's te posten
 
Very interesting Gerald!

I have two comments or questions maybe.
1: on the GR180 there is a small gap, a difference in tipheigt of the compressor and the heigt of the diffusor channels. I know this is by design, in an effort to reduce velocity somewhat. I am no expert but as I understand, all sudden changes is bad in theese velocities, it might induce a turbulence that makes the effective throat area in the beginning of the diffusor channels smaller. I have made my diffusor according to plans and you engine seem to work brillianly anyway so I might just be talking bull here

The second question is that it seem to be space for a longer combustion chamber than i the plans, this might be helpful in your monster engine, see picture of my GR180. Combustor could be at least 5mm longer?
full
 
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Tnx Melvin en Hoeby! :D


Slowswede zei:
all sudden changes is bad in theese velocities, it might induce a turbulence that makes the effective throat area in the beginning of the diffusor channels smaller.
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Yes I know, the step is in fact designed to induce some turbulence and the idea behind it is to reduce tip loss energy from the compressor, difficult to explain. Our diffusers are something else, way different compared to full-size engines. There's soo little space to do the work that extra tricks need to be done to improve pressure energy as much as possible. I did not invent this gap, just brought up by someone else to try and after some tests it worked better than a smooth transit. Some manufacturers used the same trick, Wren also did....;) Still our diffusers are in developing state, latest diffuser technology is a difficult path, calculated by cfd software. My diffuser is just a compromise to make building more easy. More on this later for my GR220 design......;)


......that it seem to be space for a longer combustion chamber than i the plans, this might be helpful in your monster engine, see picture of my GR180. Combustor could be at least 5mm longer?
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Interesting you have more space, did you use another casing with more length? If so, you could indeed make the chamber longer, no problem. It might cool the air better as there's more room to mix the air. Bear in mind as stated in my preface of the drawing they are experimental and any changes to improve engine efficienty are welkom. There aren't loads of these engines made so therefore the design stay's in testing and experimental zone, hope you understand.

Hope this helps.

Best regards,
Gerald

Grotefoto-FG73AZOF.jpg
 
Gerald Rutten zei:
Interesting you have more space, did you use another casing with more length? If so, you could indeed make the chamber longer, no problem. It might cool the air better as there's more room to mix the air. Bear in mind as stated in my preface of the drawing they are experimental and any changes to improve engine efficienty are welkom. There aren't loads of these engines made so therefore the design stay's in testing and experimental zone, hope you understand.
Klik om te vergroten...

Thank you Gerald for taking your time to answer about the reasoning behind the diffuser "step". I will for shure follow your development of the 220-engine with eager eyes!

I used the same 470 casing as you I believe, the shaft tunnel/diffusor ngv and so are allso to plan as best as I could, so I thought you had this much room to play with allso :confused: The combustor overlaps the ngv by 3 or 4mm's now so It does not seem to be displaced too far to the rear. I will only make a bigger combustor if I need to. I just thought that I would pass my findings on to you. You might need all the space for your 220 if you can fit it at all in a cv470 cannister :schrik:

I understand that your engine and plans will be perhaps, forever in development/prototype stage. But I'm very glad that you want to share this with us. I bought the complete UT170 plans but your approach to this (sharing info) made me decide what I wanted to try and build.

Anyway, will do a proper dynamic ballancing of the rotor of my engine before further tests but so far everything seems good.
 
Latest test run. up to 90.000 rpm now after dynamic ballancing (dynams pro)

Engine starts quite nice now, it seems that the move of temp probe to indicate kero ignition made starts a lot faster and less wet at teh same time. Will adjust preheat parameters and fuel ramp a bit more.

Engine seems to run very cool so far. I can not se any glow of NGV at 90.000 rpm even at night. Maybe things will change the last 30.000 rpm ;)

Found a nice piece of stainnless to use as centre body after the turbine wheel, this will be fixed next. And allso some kind of thrust measure?

Regards

Björn

http://youtu.be/DJSrzSZ8_7M
 
Very Nice Björn! You constructed the engine very good indeed! It's not uncommon to have these low temperatures with no (unrestricted) exhaust cone. Also idle is usually higher, then egt drops with rising rpm until between 75-90.000 rpm where engine is most happy. Higher rpm demands work to be done and so temps will rise again.Yours is a very good starting point! Congratulations!

Best regards,
Gerald
 
Afgelopen week langzaam begonnen met onderhoud aan de Rafale. Tank systeem na kijken, leidingen vernieuwen en alles goed nakijken. Gelijk mooi moment om de laatste luchtstart motor om te bouwen naar electro start.

Ingredienten;
Grotefoto-ZIRXAKWV.jpg


Lege romp....;
Grotefoto-Y8TOLP4I.jpg


Stoffige tank, hoppertank en verharde leidingen;
Grotefoto-YT6BT6QP.jpg


Alu huisje in wording:
Grotefoto-W7QLJSVN.jpg


Huisje reeds gedraaid met een pseudo 280 motor er in:
Grotefoto-XEDTVYEW.jpg


Groetjes,
 
MPC Permax 280BB???

Hmmm, moet nog motortje bestellen maar kan hem nergens meer vinden!!!:confused:

Ik gebruik de Multiplex permax 280BB maar overal waar ik zoek zijn ze uitverkocht, zelfs bij MPX zelf! Iemand enig idee waar die dingen nog te vinden zijn? Worden ze niet meer gemaakt of zo? Hoop wel eenzelfde type te vinden, heb een paar starters met motor diameter van Ø24,0mm, vervelend om daar weer nieuwe huisjes voor te maken mocht er geen vervanger voor zijn.

Iemand?

Grt,

332538_P_01.jpg
 
Ik zal van de week eens gaan zoeken in mijn rommelhok, best kans dat er wel ergens eentje rondslingert.

Ook al eens met W&W gebeld?

Minimaal 1tje heb ik voor je, is wel gebruikt, maar nog goed.
 
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