Two engines, sychronized together on one P.O. shaft for a boost in H.P.

[woodbowl]

When I think about needing 50 or 60 HP on a saw mill, I also think about $5000 or $6000 and 400 or 500 lbs of weight.
   A 25 HP Kohler is around $1600 and weighs 97 lbs. I can't help thinking about connecting two engines together to achieve a higher HP at a reduced price and weight. I also have a few used engines with different HP that are sitting around doing nothing. I would like to utilize these unmatched gasoline motors by putting them together on a common shaft to power machinery that require higher HP.  Does anyone know how to do this? I'm sure there are isues of RPM, sychronization, horse power, torque, ratio's and who knows what all. Surely it can be done.

[UNCLEBUCK]

I watch alot of rfdtv and those tractor pullers always have alot of engines tied together and stuffed in some old frame like 6 v-8's or even more and all power transfered to one shaft . I would think you could sure do it especially down in mr.hootie country . I just watched a show where a man took about a dozen 8 horse lawn mower engines all the same and made a tractor out of it .

[highpockets]

That is an interesting question and I have wanted to do it for years.  When I was MUCH younger I remember a dragster that had four Pontiac engines in it.  I also remember a guy locally that built some sort of garden tractor and mounted two Briggs on it. 

I worked as a rig electrician on the offshore rigs when I was only 19 years old.  We had three 750 h.p. cats pulling a.c. generators. Of course with a gen set one can watch the kw's and see if each are sychronized, and taking surge loads ok. 

I have always felt that if a fellow hooked up identical engines on a common shaft he could monitor the load via a vacuum gauge on each engine.  I have a set of 4 gauges that I used to set the carbs on my Goldwing Honda.  seems like it'd about the same thing.

My concern would be getting the power of the two to the blade.  I'd guess you'd have to run a common shaft fed by the engines then from that shaft to the blade.  I'd sure like to see you try.  Of course we need photos.

[isassi]

I saw a small circle mill sometime back that had 2 V4 Wisconsin engines on it. One was belted direct to the arbor, the other was "slip" belted and had a shaft mounted torque converter looking drive sheave. I didn't see it run, but the point would be one engine gets the machinery turning, the other is brough up to speed, and the fluid torque converter allows speed variance between the motors.

I don't know if that would be really neccessary, and actual synchronization is not needed. If both engines are tuned well, then the only problem is getting one up to speed and bringing the other "on line". If the RPM's were different, the faster running engine would slow in the cut and the slower engine would pick up the load. The only thing I can see would be maybe a larger spped drop before both governors  on the motors would be pulling down. You might also experience some over speeding as the engines come out of the cut.  Just my 2 cents.

[sawguy21]

Highpockets, you might be remembering TV Tommy Ivo's dragster. It was not very practical, mostly for show. This is a common practice. The engines could be mounted side by side and routed through a combination gearbox to a common shaft but this requires perfect sync or one engine becomes a parasitic load. Also both engines come up to speed together. This is how the Bell twin engine helicopters do it.
The tractor guys hook the engines in tandem, probably with clutches in the couplers. The torque converter idea might work the best. Probably the cheaper route.
Have a look at the Dolmette http://www.dolmar.com/755.php, a bike with 24 Dolmar 7900 powerheads through a Harley transmission. They had to slow the engines so the tranny could handle it :D

[Tom]

To do it short-time (like a tractor pull) might not be to complicated.  To do it for a long-haul job might be quite a task.  Perhaps hydraulics would solvee the problem.  It wouldn't be cheap, but if each engine drove its own  hydraulic pump that was tied to the load, the hydraulics of the slower would spend time "catching up" rather than the faster one dragging the slower one.  The affect might be more like pushing another truck down the road.  If he slowed down, you would bump him.

[slowzuki]

With a pair of small motors I can't see a problem.  One will always be putting out a bit more power than the other but it won't hurt the other one at all, it will just use less fuel.

Especially for similar motors, just get an rpm tach and set their no load rpms to match at wide open.  When they load up they will contribute what they can, won't hit parasitic losses unless one quits.

Now me I hate working on small gas motors so I wouldn't want an extra one to look after!

Ken

[D._Frederick]

Back in the fifties, I saw a sawmill operation using the stationary  JD D size tractor engines belted to the saw arbor.  When not sawing, these two engines would "fight" each other. They would back-fire and whip the belts that they would almost come off the pulleys. I don't know how they could saw with this set-up.

To get two engines to work together, they should have a "master governor" to control the engines.

[slowzuki]

It is the not sawing times that is the problem because the rpm is being limited by the idle settings and not either the load or governor.

Once they are wide open at the carb they will find their own balance of sharing the load.

[isassi]

Although impractical for this purpose, some twin engine aircraft actually have master/slave governors. The operate on electrical frequency slaving and are accurate. The 2 JD engines "fighting" each other would be more inline to what I am thinking would happen when you came out of the cut when both motors would load drop...might be interesting to see what would happen.

I have been thinking a lot about building a bandmill and if I could find a generator that would pull a fifteen or 20 hp electric motor, I think that might be the thing to do, rather then try to mount two seperate gas motors together on the bandhead.

There is one other thing you might consider. I have seen 60 hp V4 Wisconsin engines out there. They are not common, but I have seen a few on E-bay, and that might be something to be considered.

[Murf]

Somewhere in my cyber wandering looking at sawmills I came across one that ran a chainsaw motor on each bandwheel.

I don't recall if there was anything but a simple common throttle but it seems workable.  :

I would think for that sort of hp requirement it might almost be easier to run a small car engine to power either a generator or a hydraulic pump, then drive the blade with either a hydraulic or electric motor.

That way all the weight, gas engine, pump & reservoir or generator would be remote to the saw, you would only move a hyd. or electric motor and line set.  :

[Opiki]

Im not sure if adding two motors doubles the torque as same as H/P does ? Cause in the end H/P is irrelevant it is the torque that you require. I.m not sure.

In saying that as far as the engines behaviour at the end of the cut a practical fix is to put a wireless remote throttle control system in.

I have designed and put one into my Mahoe (double cut mill) and it works a treat once the engine is running one press on the button and the actuator engages the guvenor to full revs for the cut, Once the cut is completed another press on the same button drops the engine back to idle speed.
In my situation this has several benefits.(Igenerally mill by myself)

1. Less wear and tear on the engine. As I am grading and docking the cut timber the engine is only idling therefore doing considerable less work.

2. Less fuel use. with the remote I use 20 litres of diesel a day. Without about 40 litres per day.

3. If the blades jam in the cut the remote has a second button which activates the diesel shutoff valve in the guvenor therefore shutting down the engine instantly. ( no need to run a round and hit the key.
And if you arent quick enough saves replacing burnt out belts.

It could easily be designed to activate two engines in the same manner.

It works for me

[RichlandSawyer]

Back in my teenage years i got hold of two twin cylinder engines a friend and i put them in line and coupled the shafts together. these engines had about three inches of shaft out the tail and about 2 inches of shaft sticking out the fan side. we coupled the tail to fan then connected spark plugs together so both engines would fire at the sametime. We mounted it on an old modified garden tractor frame. You wanna talk torque!!! that thing could pull a 18' trailer loaded with firewood. Only used it one summer, it shredded the gears in the transaxle. It probably wouldent have done well in the winter because the spark was split between two plugs but that could be fixed with a coil to heat up the spark. I know BMW's have coils inline with the each spark plug. AAAHHHH those were the days, didnt believe anything was impossible. Dad would tell me something wouildnt work or just couldnt be done and that was like a dare.

[red]

i like how Timber King does it with one motor running the bandsaw

and a small motor running hydraulics 


another thought  is boats with twin motors  inboard/outboard

[highpockets]

Sawguy 21 I think it was Tommy Ivo.  We were down here in the sticks with no money when I was in school so we cut down Model A Fords and stuck an olds or whatever in it.  I got a 1939 Chev when I was in school.  Nice, clean. 

As for the dual engine thing, I don't think overspeed is a big problem.  I used to have to monitor our control panel on the rigs when we jacked up.  We had 36 each 75 h.p motors on the jack system and three 398 cats sychronized on 750 Kw generators. When they dropped the load (maybe 2200 h.p.) off them they may go to 62 cycles for a few seconds and settle down. 

Lets do it.  It is a good experiment.  Of course we need to use someone elses money. Maybe JPGreen 

[jpgreen]

If you don't start just calling my "JP" I'm gonna charge you a special added surcharge..  :D

[highpockets]

Well pardon me sir, I really thought there were two JP's on the forum.  A JP and a JPGReen.
You can call me anything just make sure you call me for dinner.  javascript:void(0);
javascript:void(0);

[highpockets]

I have trouble with the smiley faces showing up.

javascript:void(0);
javascript:void(0);

[highpockets]

One more try


javascript:void(0);

[jpgreen]

Dick you seem to be smiley challanged this morning..  :D

You were right about the JP thing though... I stand corrected.. 

[woodbowl]

The reason I have been pursuing the yokeing of two motors together is because of hopefull simplicity and quickness in arranging a high HP power source from either low cost motors or useless motors that are just  laying around, for instance, riding lawn mower motors. They are virtually free in this throw away society. A flat tire, dificult cranking from sitting up over the winter is reason enough for some people to buy a new mower, just like the neighbors better than the neighbors next door. They are everywhere.
    Imagine a simple coupling system that has eluded our finest engineers. In this day and time things are not made to be repaired and are designed to wear out at a given rate which is, just in time to buy a new one. Complications and high cost of parts is meant to deture repairs and a would be minor repair of yesteryear suddenly turns into a major undertaking, prompting the decission to junk it and buy new.
   This erks me to the core and it tickles me when I see people with good ideas come out of the woodwork with their latest ingenious invention. Some of the highly educated degree holders look down their long nose of knowledge and mock the origin of technology. They forget that the building blocks of progress is what they are now standing on. Money is the goal and seems to take us into the future on a roller skate filled with circuit boards and sofisticated computors.
   But some people remember, they do indeed. There are a lot of them on this forum and there are a lot that do not know yet that they have the spark of ingenuity that can explode into a never ending sea of origional and clever projects. Rbarshaw, Dangerous_Dan and many others here on the forum have been able to take an idea and go forward with it. One of my favorite programs is Junkyard wars.
    Yes, I have an idea that two motors coupled together could work very well to run a bandsaw. I am eagerly awaiting more thoughts from the wealth of original individuals that truley think for themselves.  Thanks.  :P
   
                         

[Dangerous_Dan]

Use 2 engines that are the same.
attach engine #2 to the side of the sawhead next to engine #1 but on the outside of the vertical  column.  Balancing some of the cantilievered load from engine #1 and the sawhead.
Use timing belts in a 1-1 ratio off the flywheel side of the engines to couple them together.
Make a linkage that operates the throttles the same and add a tube between the 2 intake manifolds to balance vacuum.
Hook both starters up to crank together.
Engine #2 drives engine #1 through the flywheel sides of the crankshafts.
Engine #2 has nothing on the PTO side - unless you want to add a giant alternator or whatever.
Engine #1 handles all clutching and belts as normal.
The engines will not fight each other. The problem I see is hunting up and down of the throttle, but spring adjustments and lever lengths on the linkages could possibly fix this "problem that don't exist yet".

[isassi]

I have gave this some thought, and I think the practical way to couple two engines together would be as follows: A common base, so one engine can sit in front of the other, the output of engine #1 to the flywheel of #2, PTO out of #2 to the bandhead. The governor rod from either engine couples to the other, throttle hooked to engine with "master" governor. With direct crankshaft to crankshaft coupling, then the engines will run in synchronization with no "hunting" for a balance point. Only one governor would be needed, 2 will make the engines not synchronize. I don't believe the manifolds need to be balanced, the only care would be to synchronize the carburators, similar to setting them on the old Honda and Kawasaki motorcycles.

In short, following this plan would result in one motor being made from two, aqnd maybe needing a good starter to turn both over. The would need to be coupled on cycles so you would have a true, smooth two cylinder (or 4 cyl.) engine.

It came to me that some old aircraft used back to back radial engines and GMC used to have a gas engine that was two V6's mated together to make a V12.

Richlandsawyer said he remembered two JD D's "fighting each other" on the common belt. This would be eliminated by using only one governor to run both engines.

Oh yeah, it would be simple to get a "lovejoy" or flex type coupler to work between the motors. I know this will work on identical motors and maybe work on others that were different HP, ect, as long as the manifolds were not balanced with a vacuum line. If different motors were used, the the "throw" of the governor and how much the linkage traveled would be a factor due to wanting to be certain the engines were both developing power together, and one not just along for the ride. ;)

[dail_h]

   I once sawed on a ground mill pulled by two IH engines,a ud9,and a ud6. The 9 was belted to the saw shaft,which was belted to a balance wheel. The 6 was belted to the back side of the balance wheel. They were supposedly throttled to the same speed. When the saw slowed down ,and the balance wheel took up,the govonor on the 6 kicked in ,and it took up the slack. Quite a ride,but one got used to it.