Gday,

I'm forming a fuel tank for a edf to turbine conversion. It's the Pheonix Preceptor. It'll use a K 60.

Question is how much direct air does a turbine require? My other turbine jets, Viper and F 15 have nice ducting. Im trying to keep most of the fuel over the cg. So the tank Im building will be blanking out the bottom half of the engine, Air will flow around the tank and enter the top 60% of the engine.
Will this be sufficient?
Also will ram air at speed just bypass the engine and not enter the engine?(it's an argument I'm having with a buddy, I think it'll enter regardless as the engine is sucking the air in)

The jet will keep it's first couple of inches or so of intake.

Just after some answers so I don't affect the engines performance and/or limitations. It's the first conversion I have attempted.

Also, any one who own a K60, will 1.5 lires be enough for general flying? Wont go full throttle much as the jet will be a little over powered, estimating most flight will be 1/2 and less. I tested on the stand and got 6.30mins of mixed throttle and enough for 2 missed approaches, on 1.2 litres.

cheers

Matt

Matt

Turbines are not as fussy about direct smooth air as EDF. The EDF inlets are bigger than needed on a turbine aircraft, so cutting them off and sticking a tank in front is not going to cause you a problem. Tail pipe set up to draw out the hot air and gasses is more critical, turbines don't like breathing hot air, so partly blocking the inlets is probably good.
I've only seen one Preceptor fly and it looked heavily loaded even on 6s EDF. The std legs are chocolate aluminium as they bent easily on a landing which got a little bouncy. Mt CARF Spark with a P-60 and 1.8 ltrs did 7 minutes blasting it around. Start with the timer at 5 1/2 minutes and see how you are after a couple of flights, not using full power (at all) makes a big difference to fuel useage

Dave

Thanks for the reply Dave,
I thought I was on the right track with the intake.
I have ordered a tail pipe from Jettech USA, it has a 83mm out let, dual walled for 60 size engine should be good.

Ive flown the Preceptor on 10s already as a test wether it is worthy of conversion. I think it'll be excellent with this engine. Actually landed fairly slow. It's gained some weight tho, cuz Ive strengthened the wings and glassed them. But will only be marginally heavier on take of than the EDF, .... I think.

Ive found so far the struts to be very good, I am aware of the Chinese cheese metal. Ive the same struts on my little Blackhorse Viper and they have held up to grass field op's very well after many flights.

I'll probably go 4 to 41/2 mins for a start and then see from there.

Cheers

Matt

Matt

Sounds good, guess your landings are better than the ones I saw :-)
Don't go too short or you end up landing heavy!

Dave

Turbine power does mean you should land lighter than you take off

marcs

Thanks Marc, I was hopeing for that to happen.

Matt

[QUOTE=Dave Wilshere;11908928]Matt

Sounds good, guess your landings are better than the ones I saw :-)
Don't go too short or you end up landing heavy!

No worries there Dave, Ive got over 300 meters availiable..

Matt

I had similar concern when I build my first turbine some years back, the fuel tank blocking air flow, but don't worry, it sucks what ever it needs if you have enough cheater holes in the frame. This one is powered by 60 size PST in its 8th year, still no melt down, 2 liter tank 6-8min. Good luck, J.