First spoolup of 10/98 jet engine

Home made jet engine using a Garrett TV94 turbocharger rotor, flowing ~2.33 lbs/sec .
Engine starter not powerful enough to spin rotor to self sustain rpm resulting in a hung start , possibly due to excessive rotor drag from high oil pressure (65 psi) to the OE "brass bush" bearings and thrust surfaces .
May need to reduce lube pressure during spoolup until engine stabilizes at idle

Category:

Autos & Vehicles

Tags:

• jet
• engine

[donbruce54]

Almost there. Would increasing the starter voltage give you the extra revs?

[racketmotorman]

Will be trying 18 V as a last resort , the increased no load rpm could put the starter into unsafe rpm , will try preheated oil first

[racketmotorman]

Nope, comp nut is high tensile steel , coupling 7000 series alloy , guess who won the fight :-)

[racketmotorman]

Yep, bearings felt the same as before the testing other than being a little freer as the lube heated up , the comp and turb blading clearances are reasonably generous at ~0.012" - 0.3mm for the comp and about twice that for the turb , normal sort of turbocharger clearances .

Just fitting a lube bypass to do some rpm testing with lower oil pressures .

[racketmotorman]

Yep , getting there , only another 5,000 rpm and she'd be "over the hump" and accelerating away to idle , hung starts are a bummer :-(

[mightyfinejonboy]

intense  LOL!!!

[stimps90]

Slowly getting there:) is the compressor nut rounded off now aftet that? Lol !!

[monsieurcollins]

Hi John, looks nice, saw you spin the blades by hand at the end was every thing ok for clearances?

[JETGRAN]

so close ;-)