"Fat Boy" 12/118 thrust engine

[racket]

Hi Ron

I think I'm in a similar situation, there was probably enough battery decay in the past 4 months to tip things into the hung start region :-(

Hopefully the auto electrician will confirm our suspicions

Cheers
John

[racket]

Hi Ron

Found this whilst trawing around the Net to get an idea of whats required for a stalled freepower wheel blading ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19800024211.pdf lotsa very detailed information about the entire engine , worth spending many hours digesting :-)

Cheers
John

[azwood]

Oct 13, 2019 18:22:37 GMT -5 racket said:

Hi Ron

Found this whilst trawing around the Net to get an idea of whats required for a stalled freepower wheel blading ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19800024211.pdf lotsa very detailed information about the entire engine , worth spending many hours digesting :-)

Cheers
John

I hope you can sort this out without banging your head against the wall to much more.i feel you're pain for sure but mine did run but results weren't that extieing I'll keep trying because I'm a glutton for punishment haha

[turboron]

John, thanks for the report. Chrysler and Ford did a lot of good work. I worked on automotive gas turbines in the late 60's when I got out of the Air Force. I did not know NASA supported Chrysler. I also worked on advanced centrifugal compressors with a consultant from AirResearch (now Honeywell). That experience is what started my interest in small gas turbines.

What is your background? How did you start working on these engines?

Thanks, Ron

[racket]

Hi Aaron

Yeh , keep trying , get a P2 gauge on her so you know whats happening , better to have a poor result with cool temps than a hot one with damage ..........LOL, I thought the C30 wheel would have been more than big enough to prevent that from happening , I never thought about a hung start scenario ............bummer .

Cheers
John

[racket]

Hi Ron

I started on turbine engines because my turbocharged motorcycle engine that I'd cobbled together kept on having troubles with the engine but not the turbo , so in ~1990 I thought I'd ditch the reciprocating bit and see what I could do with the turbo , went to the local library and found a kids book on jet engines and noticed that the old Nene engines of the 1950's ran centrif. comps with temps and pressures that a turbo could survive with, and the rest is history .

The little Rayjay turbo on the 90 cubic inch V Twin wasn't going to be big enough so I went and purchased the reconditioned Garrett TV84 for a 475 HP Detroit Diesel as I thought I might as well start with something big to have a chance of producing enough shaft horsepower to get a bike moving , it took a decade to get there though , not much info around in the 1990's here in Oz to help a backyard tinkerer , so I was pleased to finally get onto the Net some years later and find the old Yahoo DIY Gas Turbines Group and other guys doing similar things with turbos.

LOL.............and the hobby has kept my brain busy into retirement, unfortunately my "ambitions" have always been greater than my skill levels which has often led me into troubles like I find myself in at present, but I keep telling myself "theres always a way around it " , just gotta find it ;-)

Cheers
John

[azwood]

Oct 13, 2019 20:27:04 GMT -5 racket said:

Hi Ron

I started on turbine engines because my turbocharged motorcycle engine that I'd cobbled together kept on having troubles with the engine but not the turbo , so in ~1990 I thought I'd ditch the reciprocating bit and see what I could do with the turbo , went to the local library and found a kids book on jet engines and noticed that the old Nene engines of the 1950's ran centrif. comps with temps and pressures that a turbo could survive with, and the rest is history .

The little Rayjay turbo on the 90 cubic inch V Twin wasn't going to be big enough so I went and purchased the reconditioned Garrett TV84 for a 475 HP Detroit Diesel as I thought I might as well start with something big to have a chance of producing enough shaft horsepower to get a bike moving , it took a decade to get there though , not much info around in the 1990's here in Oz to help a backyard tinkerer , so I was pleased to finally get onto the Net some years later and find the old Yahoo DIY Gas Turbines Group and other guys doing similar things with turbos.

LOL.............and the hobby has kept my brain busy into retirement, unfortunately my "ambitions" have always been greater than my skill levels which has often led me into troubles like I find myself in at present, but I keep telling myself "theres always a way around it " , just gotta find it ;-)

Cheers
John

I'm still keen to build a bike but glad I'm learning on the kart.antill my workshops got a nice mill and lathe I don't want to attempt a bike my standards for my bikes are high and wouldn't be happy with what's in the kart it would be something more like your fat boy engine.what was the v twin you had I'm tipping being 90 cube it was a Harley I've just got a 103 cube one it's a fun bike she doesn't corner like my sport bike or stop for that matter but it pulls like a stern train.

[racket]

Hi Aaron

A few pics from the 1970's and '80's.









Bottom end was a 1,200 CC Harley side valve unit from circa 1940 which I converted to OHV by using AJS 500CC heads and home made cylinders fitted with 93mm Ford car pistons , I also had to fiddle with the valve timing as the back cylinder valves were "back to front", it was a tight squeeze fitting it all into a ~1970 Norton Commando frame , lotsa other mods necessary to cope with the extra torque compared to the original 750 CC engines output.

I initially had it on carbs , then "blown" at ~12 psi using a sliding vane blower off a VW , then in ~1981 I got a turbo of a VW converted aero engine , small turbos were kinda rare back then, only huge earthmoving gear had them

The bike never lived up to its potential , in hindsight the ignition was "poor" despite mods , and other factors made it hard to develop , I even got the welder to the cams to increase duration and lift , then I need heavy duty VW racing valve springs in place of the "hair pin" springs .................LOL, it kept me ammused for years, but eventually I needed a new challenge , and gas turbines have satisfied that for nearly 30 years :-)

Cheers
John

[azwood]

Oct 14, 2019 0:05:57 GMT -5 racket said:

Hi Aaron

A few pics from the 1970's and '80's.









Bottom end was a 1,200 CC Harley side valve unit from circa 1940 which I converted to OHV by using AJS 500CC heads and home made cylinders fitted with 93mm Ford car pistons , I also had to fiddle with the valve timing as the back cylinder valves were "back to front", it was a tight squeeze fitting it all into a ~1970 Norton Commando frame , lotsa other mods necessary to cope with the extra torque compared to the original 750 CC engines output.

I initially had it on carbs , then "blown" at ~12 psi using a sliding vane blower off a VW , then in ~1981 I got a turbo of a VW converted aero engine , small turbos were kinda rare back then, only huge earthmoving gear had them

The bike never lived up to its potential , in hindsight the ignition was "poor" despite mods , and other factors made it hard to develop , I even got the welder to the cams to increase duration and lift , then I need heavy duty VW racing valve springs in place of the "hair pin" springs .................LOL, it kept me ammused for years, but eventually I needed a new challenge , and gas turbines have satisfied that for nearly 30 years :-)

Cheers
John

That's awesome I can appreciate the work gone into it Harley parts in that frame would have upset the purests haha love it if you're not upsetting people building a custom bike you're doing wrong dad always said he was a triumph guy he liked to put Norton cranks in them and go from 650 to 912 here's the latest one think that's 9 now.

[racket]

Hi Aaron

Now that looks a nice ride :-)

I started off with Triumphs , a sprung hub 650 "paddock basher" , then a road 650 once I got a licence , with a nice new Bonneville in 1968 , such a beautiful machine , but then I started getting the backyard tinkering bug and fitted a ~1928 side valve Harley engine that I'd been paddock bashing in a rigid Triumph frame , into the Norton, followed up by the latter constructions , I wanted a good handling bike but also a larger capacity than the then average 750cc ...........not a lotta choice back in the early 70's , so guys did a lotta modifications , sadly a thing of the past .

The Norton was fitted with a Manx GP front wheel/brake and large tank as well as alloy bits where I could, she was pretty lightweight for an engine that size and pulled like a diesel engine ...............it still live on as a "vintage bike" locally , we parted ways ~16 years ago ......................LOL, I sorta blame my bad back on having to kick start that beast , it often "bit back" .

A well made turbine bike though will pull much harder and go from 0kph to 200 kph without a gearchange , they're sweet to ride, the ultimate cruiser machine :-)

Cheers
John

[turboron]

John, very interesting post. I loved English bikes such as the Triumphs, Nortons and Royal Enfields when I was a teenager. They were not available where I grew up in rural Kentucky. I tried to buy a Harley with side shifter that a family friend was killed on when I was sixteen. My parents told me they would buy be a car if I did not buy the motorcycle. Of course I went for the car.

Thanks, Ron

[htevo80]

Hi Racket
If you're using lead acid batteries they are defiantly degraded. I'd suggest as a replacement you should consider lithium batteries. They have a way higher energy density and can hold a higher voltage under load. I have an 8s lifepo4 24 volt battery on my kart and I balance charge it with an rc charger. It's been fairly easy and extremely reliable.
Gavin

[azwood]

I've still got dad's t120 (trusty) and the BSA in the track master frame (the Munster) there's something awesome about the way they made those motors back then they had soul.

[racket]

Hi Gavin

I had the batteries tested by my local auto electrician and he found them OK and easily supplying >300 Amps and suggested I check the starter which I'll be doing today .

Yep , theres better batteries available than the ones I'm using but they've been doing the job until now ,...........for onboard kart use I can appreciate why you're using the batteres you are , a much better proposition than 30Kg of lead acid .

Hows you build coming along ??

Cheers
John

[htevo80]

We'll at least the batteries are ok. That starter must be getting very hot that's alot of power.
If you buy used batteries it's about the same as lead acid with longer life. It's crazy with electric cars now.
Its going good I've just been refining the ECU and fixing a couple things to make it look nicer and run smoother. I moved away from manual oil pressure control and am having the Arduino ECU control it. makes starting it less stressful. I was going to take it out for a run yesterday but my brother pulled a muscle and could help me lift it so hopefully next week.
I've been contemplating A/B designs but that we'll be next