|
Post by racket on Feb 4, 2016 3:40:18 GMT -5
Hi Ian
LOL...........now we've got you interested ;-)
Cheers John
|
|
gidge348
Senior Member
Joined: September 2010
Posts: 426
|
Post by gidge348 on Feb 4, 2016 20:40:13 GMT -5
Hi Ian LOL...........now we've got you interested ;-) Cheers John Yes you have, just another thought, rather than mounting the power turbine at 90 degrees to the gas flow and exhaust vertically... We could mount it at ~45 degrees to the horizontal so the exhaust goes up and back and there would not be as big a transition for the gas flow. Also the diff can still be mounted underneath leaning back at ~45 deg from vertical. It would look kind of like a big T58 exhaust. www.youtube.com/watch?v=QrkGoIFJsx8 Ian...
|
|
|
Post by racket on Feb 4, 2016 22:19:07 GMT -5
Hi Ian
Yep , a 45 degree backwards angle would be just fine, certainly an improvement on a vertical shaft,............ a few more ideas thrown back and forth and we'll be there ;-)
Cheers John
|
|
gidge348
Senior Member
Joined: September 2010
Posts: 426
|
Post by gidge348 on Feb 7, 2016 7:39:31 GMT -5
Hi John, I was just wondering, I know the Nimbus engine has the power turbine NGV only about 100mm back from the turbine wheel so only a small volume between the turbine and NGV. If we lay the turbine back at ~45 degrees in the J34 (T34??) the volume I there would be MUCH greater.... wold that be an issue? Cheers Ian...
|
|
|
Post by racket on Feb 7, 2016 16:00:17 GMT -5
Hi Ian
Nope , not a problem , the gas producer is simply supplying a "fluid" that is plumbed to a turbine which could be any distance away , the further the distance the greater would be friction losses from the ducting but thats not going to make much difference to your power output .............heh heh , you won't notice the few less horsepower ;-)
In your particular scenario it'd probably be better if there is diffusion of the gases from having the standard "bullet" downstream of the gas producer turbine , the slower moving gases would then cope better with the "angular" change into the freepower's NGV .
The extra volume would "theoretically" produce a tad of lag during throttle changes , but with such a large engine nothing happens too quickly anyway , a few milliseconds aren't going to be a problem
All sounding doable to me :-)
Cheers John
|
|
gidge348
Senior Member
Joined: September 2010
Posts: 426
|
Post by gidge348 on Feb 8, 2016 23:18:18 GMT -5
Thanks John, I will just have to think about the shaft and bearings to handle the thrust/push of the gas generator trying to push the power turbine out the back.
In the engine the turbine is just bolted and splined to the rear of the compressor shaft, the compressor is trying to go forwards and the turbine is trying to go backwards so they cancel each other out.
Having a 30kg shaft and turbine running at 12,000 rpm and flying out he back like a Frisbee could really ruin someone's day. It will need some type of cross brace behind the turbine but also a pretty big thrust bearing in there somewhere.
Cheers Ian...
|
|
|
Post by smithy1 on Feb 10, 2016 17:22:43 GMT -5
John and Ian.....I like your thinking, those old J34's certainly shift plenty of air around.
Would definitely be an interesting project..finding a diff to handle all that torque may be an issue though..! ;-) But I suspect the tyres would loose traction before any shafts think of twisting..
Smithy.
|
|
|
Post by racket on Feb 10, 2016 18:15:24 GMT -5
Hi Smithy Yep , the diff would need to be kinda robust . Ian ........you might find that you can reduce your rpm considerably without much power loss , a freepower turbine can turn out 80% of its potential power at only 50% rpm , its a VERY FAT torque/power curve ............ postimg.org/image/4g1ghuvct/Cheers John
|
|
gidge348
Senior Member
Joined: September 2010
Posts: 426
|
Post by gidge348 on Feb 12, 2016 9:31:18 GMT -5
|
|
gidge348
Senior Member
Joined: September 2010
Posts: 426
|
Post by gidge348 on Feb 29, 2016 6:20:32 GMT -5
We thought that Brock (the new Grand son) should get measured up for the jet car seat. But maybe a bit longer before he can reach the steering and the controls.... But he is just the right size to inspect the afterburner. Cheers Ian ....
|
|
|
Post by madpatty on Feb 29, 2016 8:30:09 GMT -5
The kid has got a bright future.
|
|
|
Post by racket on Feb 29, 2016 16:29:09 GMT -5
Hi Ian
Cute kid , now don't go spoiling him ;-)
Cheers John
|
|
gidge348
Senior Member
Joined: September 2010
Posts: 426
|
Post by gidge348 on Mar 1, 2016 3:04:01 GMT -5
Hi Ian Cute kid , now don't go spoiling him ;-) Cheers John Ahh no problem, we will have a Tig torch in his hand crawling up a smelly afterburner in no time ...
|
|
gidge348
Senior Member
Joined: September 2010
Posts: 426
|
Post by gidge348 on Jun 15, 2016 2:53:18 GMT -5
I was hoping that someone out there that is smart with electrical stuff can help me. The jet cars wiring like most old race cars is a mess, wires change colours several times have lots of splices and terminals. Even though it mostly works, it looks like an accident waiting to happen, so I am ripping it all out and starting again. While working on the HEI igniter box wiring it looks like both wires are spliced to run to earth??? The HEI boxes have a plug with 2 wires marked A & B, A= (-) and B= (+) the outer case is earthed but others have seen are just straight 2 wires to the terminals? The system works with the earth wires connected or disconnected and there is no magic smoke escaping from what I thought would be a dead short?? Can anyone spread some light on this? Cheers Ian...
|
|
viper
Member
Joined: August 2010
Posts: 10
|
Post by viper on Jun 22, 2016 7:47:22 GMT -5
The outer case earth would be to reduce RF interference to the avionics and other equipment when it was in the aircraft I would imagine. Most igniter boxes I have seen dont have a separate case earth wire, just earthing to the frame via the mounting bolts.
|
|