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  1. #61
    CB750 Enthusiast KIRBY's Avatar
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    Quote Originally Posted by amc49 View Post
    Quit talking and build it, you will then find out. If it is as resolved as you think it will fall into place. If not..............I for one see enough problems with each idea I am tired of faulting them.
    I appreciate you allowing me to bounce my ideas off you. I probably haven't conveyed what is in my head well enough.
    Last edited by KIRBY; 04-01-2020 at 02:47 PM.

  2. #62
    CB750 Enthusiast KIRBY's Avatar
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    Quote Originally Posted by dirtdigger View Post
    you also have to look at the added shock of trying to get two engines to run perfectly the same as well as the added harmonics of two engines trying to run together.

    Yes, well I would join the two crankshafts through a hard rubber cush drive coupler. Easily obtained from a motorcycle rear hub unit, It may not keep the two engines exactly in sync, especially when one engine's gearbox is in a different gear, but with one engine firing 90% after the other, a few degrees will hardly be noticeable.

  3. #63
    CB750 Guru amc49's Avatar
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    Build it, I'm tired of arguing with you, you want to break every physics law there is. You apply it 90% and then the last 10% you ignore to kill you. I can write 2 paragraphs on why the last post won't work but you won't listen. You still never grasped that that many trans ratios to begin with are wasted, you will spend all your time shifting and to the point of it driving you crazy. At some point you will start skipping most of them to wonder why you did what you did.

    Wait until you get faced with the timing advance issues that linking two engines at different power levels and all the time changing will buy you, you will be holing pistons in one an hour after the thing is built. The lagging engine will be fouling plugs like nobody's business as it is not under load and even being held back beyond that. You will lose a BIG chunk of power simply dragging it around. If you drive the lagging engine hard enough with the on power one you will get misfires when the lagger overruns to then not get enough fuel/air to then miss as it will be underfed to not fire evenly. Study what decel valves do, Honda (at least the DOHC) already do it bad enough in stock form. You are however proposing to take that momentary condition and turn it into an all the time issue to tear up engines and I am telling you it will. So now you are adding fuel in constant running just because an engine is being dragged along and there goes your fuel mileage. And all to gain an extra trans ratio set not even needed other than for somebody's ego. You've got a serious issue with that part. People have linked countless engines together but you have never seen it done under the premise you propose to, I'd bet it has been done but whoever didn't want to publicize it as it failed miserably. Ask GM why 4-6-8 ignition failed after spending millions on the idea. Why I don't like wasting time on it.

    Your whole entire idea as posed is the money pit of an engineer and I have been THERE before. Watched somebody else lose thousands on ideas 'that will work', only they didn't. They seem to at first but then the details kill you if you insist on going there. You as well do not do things simply to do them, all effort needs to have a clearcut purpose, it helps to trim out all the waste on projects that otherwise can sink you. Part of any design criteria is efficiency, you don't do things that drag that down, the double trans and engines flopped out of plane just for sound quality when you can gain more engine power and reliability in plane and simply change the exhaust pattern only to get the sound; those things are problems of the highest order and you insist on them. It's a serious defect in the thinking there.
    Last edited by amc49; 04-02-2020 at 05:03 PM.

  4. #64
    CB750 Guru amc49's Avatar
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    Was just reading on the insanity of Nissan making a variable compression engine (VC-T) that also turbocharges and how over 300 new patents don't increase gas mileage any more than regular engines, BMW was even better with half the moving engine parts. I predicted the engineering overkill would be a waste and it is. That lead me to think back to this thread again and what Car and Driver said...........

    'The whole point of a Rube Goldberg machine is to use absurd complexity to accomplish a trivial task.'

  5. #65
    CB750 Enthusiast KIRBY's Avatar
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    Quote Originally Posted by amc49 View Post
    I'm tired of arguing with you,
    Who wants to argue? I'm just throwing ideas out there for discussion. Please don't be upset if I don't agree with all of your advice. You've brought up a lot of good points for me to consider, and helped me refine my idea.

  6. #66
    CB750 Guru amc49's Avatar
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    I strongly feel there is no refining for where you want to go, only whopping more complication. When you refine you trim back not add more. You obviously have dealt with such things only on paper. Your ten speed idea will turn out to be unworkable. Your one engine at 90 degrees will put the whole length into an unbalanced condition with different rocking moments on both halves of the overall 'engine' thus breaking parts. Straight eight engines were well known for breaking cranks even when evenly spaced as far as firing impulses, you want to make that much worse. Vibration will likely eat you alive. Why engineers laugh at straight 8 now, they are going backwards.

    You have not given any thought to trans shifting as in how? Sometimes you will shift one engine and sometimes two, how to memorize when and how? Any 'shifter' for such to simplify that would be a monstrous arrangement. Maybe 100% electric. We've already looked at what will happen when you let one side of your differential go unpowered for a second.

    Don't remember if we went over it but if the trike weight overwhelms the one motor not at power then the high power setting motor will defer to trike weight and use the diff case to try to spin the low power sprocket BACKWARD thus tearing engine up. Jack a car both front wheels in air and in park to then turn a wheel by hand and see what the other one does in a differential, it goes backwards. Your hand is the powered motor, the trans in park is overwhelming trike weight and the turning backwards wheel is the low power motor. BOTH powered inputs from the side must be at the same amount of power to drive in the same direction or you have trouble. The less power you have coming out of one side and the more weight you add to trike will add to the force trying to get out backwards through the weak side.

    You say you are refining but I haven't seen a single cure yet for all of the myriad issues you insist on still being in place.
    Last edited by amc49; 04-03-2020 at 03:08 PM.

  7. #67
    CB750 Enthusiast KIRBY's Avatar
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    OK: The design has moved forward from what I originally posted, partly because of the feedback I've received, here.
    .
    Quote Originally Posted by amc49 View Post
    You obviously have dealt with such things only on paper.
    Yes, this is true, so far.

    Quote Originally Posted by amc49 View Post
    Your one engine at 90 degrees will put the whole length into an unbalanced condition with different rocking moments on both halves of the overall 'engine' thus breaking parts.
    I have recently decided to put a cush drive between the two crank shafts, to soak up such problems .

    Quote Originally Posted by amc49 View Post
    You have not given any thought to trans shifting as in how? Sometimes you will shift one engine and sometimes two, how to memorize when and how?
    Yes, I would have paddle shifters on the steering wheel, one on the right for the right hand engine, one on the left for the left hand engine. Each would operate an electric servo on it's own shift lever. Each paddle shifter would also operate an electric servo on it's clutch cable, and ignition coil cutoffs on both engines, so engines would not run away during shifts, and the accelerator pedal would not need to be lifted during shifts A separate clutch pedal, operating both clutches, would bypass the cutoffs for pull away from stops. I would mount the bikes' gear position lights on the dash, to remind me which transmission needs to be up shifted next.

    Quote Originally Posted by amc49 View Post
    We've already looked at what will happen when you let one side of your differential go unpowered for a second.
    The aforementioned dual engine ignition cutoff switches during shifts.

    Quote Originally Posted by amc49 View Post
    Don't remember if we went over it but if the trike weight overwhelms the one motor not at power then the high power setting motor will defer to trike weight and use the diff case to try to spin the low power sprocket BACKWARD thus tearing engine up.
    I have relocated the spider gears to within the rear wheel hub. , driving them from the two large (sun) gears, one on each side of the hub, (search 1901 Locomobile Differential for the layout, though mine would drive from the sun gears) When both sun gears are rotating at the same speed (same gear) the spider gears would be locked,(pulled forward at the same speed on both sides) and the wheel hub would rotate forward at the RPM of the two sun gears. When one sun gear is rotating faster than the other (different gears) the spider gears would rotate on the spider , somewhat like rolling a pencil between your two palms, and the spider and wheel hub would rotate forward at an RPM that averages the two sun gear RPMs, thus giving a gear ratio between the two inputs. With the two crankshafts joined, There would never be a case where one side is held stationary.If one engine "dies", it would still rotate at the same RPM, being pulled through the cush drive linkage by the running engine.
    Last edited by KIRBY; 04-04-2020 at 12:36 AM.

  8. #68
    CB750 Guru amc49's Avatar
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    'There would never be a case where one side is held stationary...'

    Not possible, the vehicle weight can do it through the center of your diff. Then the power engine overrules the weak one. Say at a heavy load takeoff. The vehicle weight is more load on the diff than the weak engine is, weak engine loses and tries to turn backwards. A diff rolling straight forward does so based on EQUAL power coming in from two directions. Why a diff gives on one side when a corner is turned. The only way to avoid that is two one way clutches in the diff side drives. A diff that lowers power on one side of it loses drive on the other side as well. Unless both tires are firmly planted on a surface one side of any diff is essentially freewheeling not attached to anything.

    As far as the moving of the spider gears you are absolutely lost there, spiders cannot be remote and work as such. And way out at the end of the axle? I saw the 1901 pic but it is a conventional differential in 100% of its' action.

    You can't drag a lower power engine with higher power and both at the same time, the lower power one will tear up after a point. When you spin it with no power the piston inertia forces reverse and you will crack skirts. And your adoption of a rear wheel hub as a joining point is going to bite you hard too. Your coupling will actually need to be splined, steel, and covered entirely to run oil in a case or it will not live.

    You are talking easily a $30K -$50K effort there with no trouble at all getting there. And undrivable to boot. I still see no solving of the true problems at all.
    Last edited by amc49; 04-04-2020 at 02:51 AM.

  9. #69
    CB750 Enthusiast KIRBY's Avatar
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    Just gonna have to win the lottery, and build it.
    Last edited by KIRBY; 04-04-2020 at 01:24 PM.

  10. #70
    CB750 Enthusiast KIRBY's Avatar
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    I think I see the miscommunication

    Quote Originally Posted by amc49 View Post
    As far as the moving of the spider gears you are absolutely lost there, spiders cannot be remote and work as such. And way out at the end of the axle? I saw the 1901 pic but it is a conventional differential in 100% of its' action.
    That statement makes sense in a trike with two rear wheels, but, my trike is a reverse trike, with only one wheel at the back. That wheel rides on bearings, with the spider and it's four spider gears riding within the hub, and in the same plane as the hub. Sun gears on each side enmesh with the spider gears. When one sun gear turns faster than the other, the spider gears have to spin to keep up with the two sun gears' teeth (like the pencil between your palms - try it. hold one palm still, and move the other forward. The pencil will spin and move forward half as fast as the moving palm.This is the differential travel.) In the trike, one sun gear rotating at 200 RPM, and the other at 100 RPM will result in the wheel rotating at 150 RPM,the in-between speed.
    Last edited by KIRBY; 04-04-2020 at 12:22 PM.

  11. #71
    CB750 Enthusiast KIRBY's Avatar
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    OK, this drawing is a bit rough, but this is the general idea of the single rear wheel with built in spider gears:
    Attached Thumbnails Attached Thumbnails motorcycle wheel and tire.JPG  

  12. #72
    CB750 Guru amc49's Avatar
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    Since most weight is on the front there then that would lower the ability of the weight alone possibly empowering the diff to turn one engine backwards but does not get rid of it completely. And you just added 100% more complexity by making the front end with two wheels have to be suspended when you could have simply used a bike fork assembly to do that. Now you can't, and now you have to invent a steering system that will work too.

    It's like you are trying to go out of your way to make the most inefficient most expensive vehicle you can. Nothing about the way you are going about things is the smart way to get reliability and easy to build. Add another $10K to that price by deciding to run it backwards the way you are, you show no sense with almost every choice you make. Nothing personal intended there at all but it is what it is. A much more logical choice for a backwards trike is modifying say a FWD car to use the front half only and power that and simply use a non-power rear wheel. I have a zetec ATX Contour that could be used for that easily and it mounts on a solid subframe that can be modded to weld on an extension to the back for seating and the rear wheel which can be another fork flipped backward and locked down. 70% of the work already done for you. 130hp. and 130 torque already and easy to add another 40 to it and still bulletproof. Careful choice of car and parts could build it for under $10K.

    Good luck with that lottery, myself, I never play, I know a voluntary tax when I see one. I will never win but I win in essence $2-$5 every single week that others play on. It adds up.
    Last edited by amc49; 04-04-2020 at 07:12 PM.

  13. #73
    CB750 Enthusiast KIRBY's Avatar
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    I'm still not seeing this "turning the other engine backwards" thing. Yes, on a conventional car, if you have the drive shaft in park, and you turn one wheel, but this setup is not like that. Since the power(s) flow the other way, the rear wheel would take the place of the drive shaft, and move forward. Both engines act as one, with the crankshafts tied together through the cush drive coupling. They HAVE to both turn together. This differential is not like a two wheel rear end with one ring gear. There is a sun gear on both sides of the spider setup. The spider gears do the adjusting to prevent the two suns from being locked together, when in two different gears, and that adjusting is what gives the in-between gear ratios. IF the wheel were not allowed to rotate, THEN the engines would bind up, (the same would be true even if the two transmissions were in the same gear.)but the spider gears allow the two sides to rotate at different RPM while turning the wheel at an average Rpm of the two sides. The front end would be from an air cooled VW Beetle, and both engines would be behind the driver and passenger seats. Words are not working for me to show you what I mean. Think I might buy an RC car bevel gear set, and build a physical Proof Of Concept model. (Oh, yeah. I don't do the lottery, either.)
    Attached Thumbnails Attached Thumbnails Differential Gears For RC Car.JPG  
    Last edited by KIRBY; 04-04-2020 at 10:40 PM.

  14. #74
    CB750 Guru amc49's Avatar
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    Dude, you are still missing that you have a standard differential there, I don't care how much you say no. And misusing the term sun gear too there is NO sun gear anywhere in a spider gear set, only in planetary. Another gear has to revolve around the sun and NOT in a concentric way, you have all concentric gears there where one line can go through the dead center of all gears there, that makes none of them suns. A sun MUST have a planet to make it a sun, or TWO lines through TWO gear centers that are NOT centered on the same line. Example..........earth north to south axis and the same on sun, they do not ever touch.

    'IF the wheel were not allowed to rotate, THEN the engines would bind up...'

    YES, because one begins to try to turn backwards. Car jacked up in the air you are doing the same as increasing trike weight with trans in park, then turning one wheel reverse turns the other. You cannot escape it. Your wheel turned is the power one with no power on the other, equal power is a lockup.

    ' There is a sun gear on both sides of the spider setup.'

    No, that as explained is NOT a sun. Consider it end of axle, doesn't matter as it impacts nothing.

    You can hold ANY part of a three drive/driven element diff to make the other two act differently. The amount of power applied affects the output hugely, it can switch the output axle back and forth depending on the amount of load on each. LOCK the center final drive to the trike ONE WHEEL and then study what only ONE engine puts to the diff gears, assume it is the high power one and watch what the other side gear does not u7nder power, it tries to go BACKWARDS. Why one wheel up in air does it.

    You are correct in the engines being locked together and where I went in the first page of posting on this thread, that it would explode something. What should happen if you lock engine drives together and then try to turn them in opposite directions or same direction at different speeds.

    The ONLY thing you have different there from a standard differential in a car is that you are putting power in it BACKWARDS through the outputs rather the the input. And trying to vary the outputs with the locked together at the engines while turning different at the diff case. Why I've said all along it cannot work.

    Somehow you are weirdly thinking you can lock two engines together in output at crank yet have them enter later in varying amounts of rpm, they CAN go into the diff backwards like that but then how do you resolve the fact they are locked together at the cranks to not be able to speed independent of each other??? You can't magically have same rpm locked and the same output later be different with no change in between unless they stay in the same gear. Change gears and it blows up.

    I reached this conclusion once before then started second guessing myself, no more. Clear as a bell on it now.

    BUILD YOUR MODEL, you now HAVE TO. IT WON'T WORK.

  15. #75
    CB750 Guru amc49's Avatar
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    'This differential is not like a two wheel rear end with one ring gear.'

    WRONG, it is EXACTLY the same thing.

    '...the rear wheel would take the place of the drive shaft...'

    Incorrect, they are already essentially the same thing. Nothing changes operationally there at all.

    You need to simply throw the diff away and do this. Take two engines and lock the cranks together like you propose, then connect a chain between each using same sprockets on both and start engines both at 1000 rpm and put one in first gear and the other in second and let the clutches out and see what happens. You WILL tear something up, it's called being in two gears at once. I've seen race trans do that and it blows to smithereens. The only way you don't is the two engines absolutely cannot be connected at crank.

    Your problem is not the differential, it's trying to carry differential power TO a differential, you can't do it under those circumstances.

  16. #76
    CB750 Enthusiast KIRBY's Avatar
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    I'm tired of trying to convince you. I'll be back with my model.

  17. #77
    CB750 Guru amc49's Avatar
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    I understand that you think the difference in drive speeds is auto-evened out with the center gear adjusting for the difference in the two side speeds. It may not blow up instantly but at the least you have added loads onto the three drives that are absolutely unnecessary. Your engine coupling will be overloaded due to it and your insistence on putting the two motors out of sync too. Your clutches at the least will go through hell and DOHC clutches go out pretty quick in stock form so you may not want to use those engines and also because they miss so easy on overrun like one engine at very high power and the other one dragged along for the ride.

    Another thing to think about with this mutation of yours. Differentials are designed to only use the spiders on limited occasion, when you split power through them all the time like you propose, the spiders wear like lightning, they were never intended to be used like that 100% of the time. Most of the time they rotate as a single unloaded mass not turning, the friction then drops a huge amount. Spider gears sap torque like nobody's business, there is scrub loss in there.

    Even if the model works you have so many issues injected in there by you that the outcome will likely be bad. I build successful engines of all types both bike and car and those issues are screaming no on this project. My view is that you have tried to design the most unworkable device you can think of. You can't possible convince me out of that, model or no.

  18. #78
    CB750 Guru amc49's Avatar
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    Another thing you haven't considered is chordal wear based on using the spiders so much as power splitters. Spiders have very wide teeth and the chordal effects go way up with them. Not a problem when rarely used but all the time like you want? I envision you changing the spider gearset every 6 months at the least from undue wear just for that.

  19. #79
    CB750 Enthusiast KIRBY's Avatar
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    Quote Originally Posted by amc49 View Post
    I understand that you think the difference in drive speeds is auto-evened out with the center gear adjusting for the difference in the two side speeds. It may not blow up instantly but at the least you have added loads onto the three drives that are absolutely unnecessary.
    I realize that the power through the two engine/transmissions will be unevenly split when the two are in different gears. I've calculated the highest imbalance to be the 1/2 gear combination at 120%/80%. That's why my initial question of whether a CB 750 engine could handle an increase of 25%.

    Quote Originally Posted by amc49 View Post
    Your engine coupling will be overloaded due to it and your insistence on putting the two motors out of sync too.
    Perhaps I don't need the out of phase. I can set the coupler to have L1 and R4 fire together, followed by L3/R2, L4/R1, and L2/R3. Should smooth out the rocking, and the shock on the coupler.

    Quote Originally Posted by amc49 View Post
    you may not want to use those engines and also because they miss so easy on overrun like one engine at very high power and the other one dragged along for the ride.
    I'm not sure what you mean by "miss".

    Quote Originally Posted by amc49 View Post
    Another thing to think about with this mutation of yours. Differentials are designed to only use the spiders on limited occasion, when you split power through them all the time like you propose, the spiders wear like lightning, they were never intended to be used like that 100% of the time.
    And I wouldn't. Only in acceleration would I use the half steps. Cruising would be in matched gears, so the spider gears would not spin on the spider.


    Quote Originally Posted by amc49 View Post
    Spider gears sap torque like nobody's business, there is scrub loss in there.
    I've shown straight cut bevel gears, but there do exist helical cut bevel gears.

    Thank you for giving me more to think about. You've probably talked me out of 8 separate firings, and into four couples of firings.
    Last edited by KIRBY; 04-05-2020 at 08:12 AM.

  20. #80
    CB750 Enthusiast KIRBY's Avatar
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    Quote Originally Posted by amc49 View Post
    there is NO sun gear anywhere in a spider gear set,
    Yes, I see. Perhaps I should call them Side Gears and Spider Gears. Thanks.

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