dieselguy86
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Post by dieselguy86 on Apr 16, 2022 15:17:33 GMT -5
Today's "haul" includes the final bits for my ignition system (thanks Monty!) and a 4" x 6" piece of high temp ceramic glass. I guess it's not really glass, rather just transparent ceramic, the Neoceram is capable of withstanding 1,470°F at only 3/16" thick. Was $39, expensive for the size of it, definitely affordable tho. I'm going to be doing some combustor testing here soon under real world flow/pressure on a setup I have to try and work out the best way to use these injectors. This glass will let me see what is going on, I'll post more on that when I get to it. Side note, health has been improving so the build shouldn't really slow down much. Work is getting in the way more than health. -Joe
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dieselguy86
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Post by dieselguy86 on Apr 11, 2022 17:38:25 GMT -5
Reason for the grooves is not to get oil to all the holes, that's the "scallops" job.
The grooves on full floating bearings reduce the centrifugal pumping affect on the oil.
On semi-floating bearings the grooves DO distribute the oil to all the holes.
-Joe
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dieselguy86
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Post by dieselguy86 on Apr 9, 2022 16:13:44 GMT -5
Hey guys, Well, wasn't a 100% successful day. I didn't fail, I just found 1 way not to do it. First issue was I forgot to put a flat on the motor shaft. The set screw just slipped as soon as the pump started making pressure, no big deal, and got it sorted quickly. The big failure was I didn't pay attention to the direction of the "grain" of the 3d printer. The motor holes were drawn in a square pattern, 2 holes horizontally in line with each other, coupled with a horizontal "grain" meant there was a quick and easy place for the mount to snap. I can fix it by adding some more gussets and changing the printing pattern. What I did find out was the "injector" pops off at ~220psi with a pretty nice atomized spray. I got it up to 400psi before I decided holding the shaking motor with a pair of pliers was to sketchy to continue. I don't think the low kv motor and 12v battery will get it to the 1,000psi full throttle mark anyways. 24v should handle it just fine. I didn't get a chance to really get a good look at the spray angle, but it appeared to be pretty narrow, guessing 20-30°, with a good amount of axial travel. I'm thinking it's going to take some combustion testing to use some opposing mixing holes to get the fuel spray redirected so it's not trying to travel so far down the combustion chamber. I have some ideas and tricks to get this done. Right now I'm getting the printer warmed up for tomorrow's test. I gotta say I don't miss the smell of diesel on my skin, but it is nice to be "back in the saddle"
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dieselguy86
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Post by dieselguy86 on Apr 9, 2022 11:31:42 GMT -5
Your about right, 40mm is good for around .4 lb/sec mass flow. Using John's educated guess of 1 lb/sec for 50hp, you'll be pretty close to 20hp.
Your biggest headache will be figuring out the freepower unit.
I would go up to gt35 sized, you can find ball bearing ones cheap, pair it with an hp841 freepower unit and you won't have all that much invested, both time and money. Reason I say bb is because it takes alot less oil, and you have alot less oil heat to worry about. Having a bush turbo and freepower will need a good oil supply system when the oil gets up to temp.
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dieselguy86
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Post by dieselguy86 on Apr 8, 2022 21:55:57 GMT -5
Hi John,
Not to mention, one thing I've learned with my wren 44 heli engine, is that turbo-shaft engines don't run at 100% throttle as often as thrust engines. Saving the bearings even more. I bet you're right, run a filter on the engine and id bet those bearing services could be pushed to 100 hours.
-Joe
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dieselguy86
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Post by dieselguy86 on Apr 8, 2022 19:31:56 GMT -5
Gerald Rutten's website has plans for an engine that would fit your needs pretty well. It's not "industrial" quality (sealed shaft tunnel, closed loop oil system) so it'll need rebuilt more often, but atleast you have a solid set of plans to build from, taking alot of guesswork out of it. The compressor needed for it is available from kts. -Joe
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dieselguy86
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Posts: 186
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Post by dieselguy86 on Apr 8, 2022 18:59:51 GMT -5
Electric go kart accelerator came today, somethings "just work out". The kar-tech pwm driver takes 9-30v, and has a 5v output. The pedal takes 5v as power as sends the output signal to the input of the driver. The driver converts that to pwm and "drives" the solenoid. It looks messy in the pic because I hurriedly hooked it up, but it works great. If anyone decides to use this driver, I highly advise to buy the optional gate programming tool. I cheaped out, the method of installing and pulling jumpers and turning a small pot to dial in all the settings is quite cumbersome. I now have the gate tool coming. Hoping to have some fuel test numbers tomorrow, I finally have everything I need to get that done.
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dieselguy86
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Post by dieselguy86 on Apr 6, 2022 22:40:25 GMT -5
Hi John,
Today was already better than yesterday, so hoping it's a stress/rest ordeal and it doesn't hold things up too long, been wanting to do this for 2 years now. Good wakeup call to what is important in life, and that I'm not 18 anymore lol.
The good parts are starting to roll in now and the excitement is building. Forgot to mention the solenoid piece sitting on the pump base is the proportional relief valve for throttle. A couple oring fittings and it'll be plumbed in. It'll be controlled from the pwm valve driver I bought earlier. That is controlled by a potentiometer input, had no clue what pot to get, then the work to design up a bracket and pedal assembly to use it. Good ol ebay found me an accelerator pedal off an electric go kart, a nice shortcut I'll gladly take lol.
Only thing I haven't worked out yet is a good strong ignition system, was almost thinking glow plugs.
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dieselguy86
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Post by dieselguy86 on Apr 6, 2022 20:25:42 GMT -5
Pump motor and driver showed up yesterday. I already had the mount designed and 3d printed. Downloaded spyder couplers from McMaster and edited them to fit, then printed those as well. Ordered the flex coupling and it fit perfect, also got the rest of the pieces put together to test popoff pressure, spray pattern, and flow rate, and then the kicker happened... Apparently the last month of 15hr days every single day, caught up to my heart. Er visit showed positive results, so was not any kind of heart attack, Dr appointment tomorrow, but so far hoping it's just stress induced. I've already canceled the end of May show that was my deadline. Sucks but its not worth my health. Here's a few pics of the test rig.
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dieselguy86
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Posts: 186
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Post by dieselguy86 on Apr 4, 2022 22:44:23 GMT -5
Hi John,
Yep, I'd rather have too much starter power than not enough. I converted an AMT engine to autostart with a brushless motor and once the ecu settings were dialed in, haven't had one single slow or failed start. Brushed motors just don't have the oomph that brushless ones have.
I actually have plenty to take pics of, fuel system is in, turbo is assembled and ready for cc, once flanges come in it'll only take a couple of days to get cc built and test run made. Besides the normal p2,t2,tit and p4, any other things to measure? I'm going to try to get it all on my banks idash gauge, which will allow me to have shaft speed as well.
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dieselguy86
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Post by dieselguy86 on Apr 3, 2022 15:05:26 GMT -5
Hey guys, Thought id give a bit of an update as i havent posted in awhile. Despite 10hr workdays on my full time job, and then an additional 5hrs at night on turbos, ive been making progress on the engine. i have to since i have an end of may deadline. I thought i had most of what i needed to be able to get it put together quickly, but the more i get the more i realize i need. Designing multiple systems from the ground up is alot of work. Respect to everyone here who makes it look easy! Gt42 chra showed up from china last week, im amazed at the prices they sell them at, only $87, although shipping makes up for it. Had to machine the comp cover to fit, nice fiddly job that was. Was only off a few mm, not worth taking it to the cnc lathe, so lots of small cuts and grinding to get it right. Next was starter system, I thought this starter would be up to the job at 15k rpms. but once it showed up today, testing showed it definitely wasnt. was only able to get around 5k rpms with no oil, and after ~20 seconds the motor started smoking and wires were warm. But i REALLY liked the starter cone on it, so i measured the shaft diameter and went a hunting. Found this motor on ebay. its the right shaft diameter and 2100kv at 13.5volts should get me around 25k rpms unloaded, hoping 15k loaded, which will increase once the fuel is lit. Bought a push solenoid from mcmaster that will push the motor to start. Next thing ive been thinking on is the fuel and oil system. im not against electric powered pumps, i just think its alot of extra "stuff", wires/relays/switches/fuses etc that seem to give everyone grief. i found the cvt transmission input constantly spins, and there is a centrifugal clutch on the secondary clutch, so this means the input shaft of the transmission will always be spinning. Since i have to make my own input shaft anyways, my plan is to extend it out of the belt cover and use it as an ancillary belt drive. Only problem is that during start up, the power turbine wont be spinning enough to power the pumps. well i think i found my solution. when i bought that sullivan starter, i found they also make starter/alternators for uavs, you can browse the controller here, and the starter/alternator here. I think im going to put a one way bearing in the ancillary drive belt pulley so that in start mode the motor will only be spinning the pumps, but once the power turbine comes on, it will take over and be doing the driving. almost everything is here for the combustion chamber, just waiting on a couple vband flanges to show up so i can construct it. im not sure im going to have time to wait for the inlet manifold to be casted, so i might end up with a more normal inlet. In order to get all of this done in the remaining month and a half, its going to come down to time management. i can build a new combustion chamber relatively easy later, so as long as something simple can work now, ill be happy. im not the greatest at taking pics, but i promise ill get some loaded here soon, its just been parts and pieces showing up, with lots of measuring and thinking.
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dieselguy86
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Post by dieselguy86 on Mar 12, 2022 13:12:43 GMT -5
Monty, Yep, that's why I bought a 3d printer, I can design and print whatever I want and try it before I waste metal. My only limitation is that I suck at cad modeling lol. Worked on mating the 841 output to the transmission input, this turns out to be super easy. All I need is a 1/2" adapter plate, and the 841 case drain fits into the 150cc case's drain. Here's pics of where I got last night... Came in and drew up an adapter while my cc "manifold" finished up after 36hrs of printing. You can see some obvious modeling errors that I need to learn how to fix, but it should be good enough to test for now. I'll fix it to my leaf blower with some strings taped to the straightening vanes to see how much swirl there is. I didn't get any pics of the adapter, but dumbass me copied the 841's bolt pattern mirror opposite. Not a big deal, I ended up having to move the drain hole as it would hit the fwd/reverse shifter. I actually like it better now, there's a baffle and a longer path for the oil to travel to hopefully get some of the air out. Once joined together, I could fit it into the frame, where I found out mating the freepower to trans was the easy part. With the hot section I'll be into the tire, I measured and I can shift everything to the left a solid 4", maybe 6" with some moving of some other components. I guesstimate with engine I'll be ~26" long from 841 output flange, to gt42 inlet flange. In afraid my only option is going to be too mount the engine beside the freepower unit, and have a 180° bend from engine to the 841 hot section. Not ideal but it is what it is. I'm not going for a world record or anything so I can live with the free hp penalty.
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dieselguy86
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Post by dieselguy86 on Mar 11, 2022 12:20:15 GMT -5
Monty,
That is awesome, their basic holder is only $425, I'll contact them to see about what broach I'll need. Making my own may or may not be cheaper, but it'll definitely be faster and give me future possibilities.
-Joe
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dieselguy86
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Post by dieselguy86 on Mar 11, 2022 8:58:45 GMT -5
Hi Monty,
I don't have access to much, I have a manual lathe is all. Buddy of mine has cnc lathes and mills, I can ask if he has a rotary broach holder.
If I could cut the splines myself that would be great.
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dieselguy86
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Post by dieselguy86 on Mar 10, 2022 23:03:52 GMT -5
Ron, I found them on ebay, I was lucky to get mine for $250 cause after that they went up to $750. Spent some time in the shop tonight, I was hoping I could get the kart to start before I tore it all apart, but when it wouldn't start even with ether I knew something was damaged. Stripped the head off and the piston was junk. So got the engine/ trans ripped out to see what I was working with. I hoped the engine was a seperate casing than the transmission was, it wasn't. I have half a case I need to machine off before I figure out how to adapt the hp841 gearbox to it. Then there's the hp841 I have to figure out as well. The output is a 17 tooth starter gear that does me no good. It looked like it was held on by a bolt so I popped it off. Under the bolt is a thick washer, and it does not want to move. I ended up hearing it cherry red and got a chisel to bite into it and it popped off. It's recessed and probably press fit, explaining why it was so hard to get off. But that was the easy part, the hard part was the gear. They didn't want it going anywhere. I heated it up to a dark blue and it took several beatings to get it to pop off. One off, here's the output you have to work with... 1" shaft, 18 spline, which is kind of hard to find, but I only spent 15 min browsing. I need to go from that to about a 15mm shaft for the cvt transmission primary clutch. I'll probably end up machining the shaft myself and find a gear cutter that can cut the splines for me. Unless anyone has a better idea.
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