Heymow - Lawnmower Racing Forum
Mower Building / Setup Help => Driveline => Topic started by: marcritter on October 04, 2009, 05:38:00 pm
-
Is it okay to run an actual driveline from the motor to my tranny. Kinda like a divorced trans setup. I was under the assumption that i cannot rotate the motor to run it sideways. i tried searching this but i never really get to far with the searching on this site. don't want to run the belt down and around some bushings to make it level with the tranny like it is currently. Of course I I would do this safely with a driveline loop and anything else that i need. It would also be a perfect place to attach a good big braking system to.
Any thoughts....
-
Is it okay to run an actual driveline from the motor to my tranny. Kinda like a divorced trans setup. I was under the assumption that i cannot rotate the motor to run it sideways. i tried searching this but i never really get to far with the searching on this site. don't want to run the belt down and around some bushings to make it level with the tranny like it is currently. Of course I I would do this safely with a driveline loop and anything else that i need. It would also be a perfect place to attach a good big braking system to.
Any thoughts....
If im reading this right, how would you incorprate a clutch? Basically you mean like a driveshaft RR drive cars, Right?
-
Yes thats what i was thinking of doing. and yes i have been trying to think of a clutch and have a few ideas but that would be maybe another thread. I was just curious what the deal is. Believe me I've read the rules numerous times and it says if its not here then you can't do it but there are lots of mods happening that weren't discussed in the rules so I thought I would ask. And any ideas or thoughts would be cool too.
-
I doubt you would find a tranny or transaxle that is mower orginated that
would hold up to a direct drive shaft
-
What rules are you building to?
-
I'm not 100 percent sure, but I thought that all the ARMA classes other than pro-x & supermod had to have a vertical shaft engine.
-
I don't think you will find a club that will allow that. That is a system you would have found on the old Cub Cadets etc that you see pulling. That option was only available on a Garden Tractor not a Lawn Tractor so it would outside the scope of the Lawn Tractor racing rules.
-
uslmra rules, with an opposed twin. Heres what i had in mind. I am thinking with the motor size and what not I would go with B/P
-
CP is where 20 HP and under OHV and valve in block twins run. USLMRA rules allow you turn the motor. It only states that the PTO has go through the original clearance hole. Turn it sideways and add a RAGB (right angle gear box)
-
You need a different transaxle. Find a Peerless 820 if possible.
Look in the build section for Son's build. That is what you are
looking for.
http://www.heymow.com/index.php?topic=2457.0
-
You need a different transaxle.
How did you come to that conclusion? Nothing in this post says what he currently has. I agree with you the 820 is the best tranbsaxle to have, I just can't see how you can quantify that statement.
-
CP is where 20 HP and under OHV and valve in block twins run. USLMRA rules allow you turn the motor. It only states that the PTO has go through the original clearance hole. Turn it sideways and add a RAGB (right angle gear box)
1) Engine must be originally manufactured for use in lawn mowing equipment and be stock in appearance, with the exception of air filter, air cleaner or velocity
stack. Crankshaft must be in original orientation and clearance hole in the frame.
Engine may be internally modified.
No, you cannot change the orientation of the engine in prepared classes. Only in FX!
4) Driveline may be modified from the engine pulley to the rear wheels, but must
utilize a shiftable lawnmower transmission or transaxle. Vari-drivers may only
be used in an original installation.
you could use a driveshaft, if you could do it without changing engine orientation?
6) No centrifugal and or torque converter clutches.
Don't forget this
22) Must use axle mounted brakes, no lawnmower transaxle or transmission
mounted brakes.
Nope, couldn't put your brakes under there.
Now with all the legality covered, I must ask....Why?
All you've accomplished is a whole lot of un-needed weight!
Belt drive is easy, reliable when done right, and the lightest way to mow!
-
Im not saying im right here but, the straighter you can get the drive the better, a pulley setup you would think you would lose power from the change in verticle to horiz and vice versa. Now how much power, i dont know, enough to tell? proably not.
-
I realize I should have used the term "rotate". He has a horizontal shaft motor, he isn't changing the orientation of the PTO by turning it so it sticks out side to side instead of front to rear. As far the clearance hole, it doesn't technically exist on his mowchine, does it? Anyway, with a RAGB he can have a "normal" clutch on the horizontal belt going to the transaxle.
I could be very wrong as Rooster points to some very good information from the rule book. But I still think it would work. If you are gonna run at sanctioned events, I would contact the respective technical advisors to find out for sure before you jump into a build that can't pass tech.
-
How did you come to that conclusion? Nothing in this post says what he currently has. I agree with you the 820 is the best tranbsaxle to have, I just can't see how you can quantify that statement.
I see, several posts ran together, and I got distracted on this one,.
-
I have a newer cub that runs with a drive shaft the only downside is its a hydro so it wont work... also you wont be able to change your pully's... if I read this right???
-
wow you guys are awesome to be debating like this over my post. thanks guys so much. so my problem with all this is that i don't want the belt running on the bushing if i get a little mud and seize the bushing then there goes a belt. also with my five second design ( obviously needs allot of refining) it gives me an option to change the pulleys (top and bottom) to give me different ratio's. also the clutch is simply a tension pulley.
no cent. or torque type clutch. the brake was just an idea but i will definitely follow the rules. also the rotational weight ( if any) might give me a little more stick on the outside....maybe lol
-
You should be able to replace the bushings with two pulleys right???
-
that might also work i was also thinking that i might be able to get bigger bushings and put sealed bearings in it i guess. Does a pound or two make a difference overall on these things? I never thought about the weight being a problem with the drive shaft.
-
while a pound or two does not make a difference, that pound, this one and the 30 other spots you could of saved it does!
And I doubt what your talking about would be a pound or two.
-
so I can't twist the motor 90 degrees in C/P class. I shouldn't add the drive line because of too much weight.
So i'm left with what i have to begin with and should just update the rollers.
-
No, you should look thru the build section at proven driveline layouts and copy what works and is dependable
ie: 700 and cart axle or 600/820 trans axle and jackshaft
-
Humble opinion here, call the USLMRA (847-272-2120) or ARMA (http://www.golawnmowerracing.com/contact.php) and ask the Technical Advisor if your motor can be turned 90 degrees and still be legal for the class you want to run in. This sport is not an absolute science yet. Of course there are many PROVEN things to do (700/live axle) but that does not mean something else won't work or be legal. I still think that rotating the motor adding a RAGB and putting a "normal" clutch on the horizontal belt would be legal. You haven't changed the orientation of the motor (taking a vert shaft and mounting it horz.) You are still using the original clearance hole for the PTO, (there technically isn't one). You are not using a centrifical clutch, and still utilizing a shift-able trans axle. Again my advise is to ask the head honcho, not us peons that like a certain set-up (I prefer the 700/live axle btw)
Toad
-
Its not so much a matter of legality as it is of practicality....
Twisted belt system simply won't hold up to the higher rpms of a racing mowchine, allow a slip clutch to work properly, and loses a good bit of hp in the twist...
It's not the first time some one has tride this and the result is we don't see many (if any) on the track that do work.. even a little
So why try to reinvent the wheel when there are proven methods that work and work well
If you have time look up Case racers setup with a cub clutch/driveshaft direct to 700 set on its side...Nice idea, but impractiable and hard to keep together.
Not trying to discourage "thinking out of the box" but alot of these "new" ideas have been tried numerous times before and for various reasons didn't (don't) work out
Just trying to save you from the hassle and dissapointment and set you on the right track with again a proven/reliable setup
-
Correct the twisted belt systems do not work for higher RPM machines and I agree with you, "Why re-invent the wheel?"
I stand behind my idea as it is being used by others, maybe in other clubs/classes but it is a viable solution to his mower, just maybe not for the class he wants to run. That is why I continue to point towards the tech advisors of the sanctioning bodies to get their input. They would, in my opinion have the final say about rotating the motor and using a RAGB to take the horizontal PTO (vertical belt) and turn it 90 degrees to run a horizontal belt to a transaxle. This set-up is used by Hitch on one of his builds (accept the class it is built for allows centrifical clutches) I have also seen FX and AP machines using the same concept with jackshafts and chains. The idea is soild, the question remains; will it pass tech for USLMRA's CP class?
-
If you used an ragb to make the 90 then went to mower tranny/transaxle with a belt clutch then yes it would pass USLMRA tech
At that point though you wouldn't really need to "turn" the motor from original orientation to get the 90* effect...
-
I suppose there might be room to do that. Hmmmmm what if you simply coupled the the RAGB and the PTO shafts and eliminated the one belt.......? That might actually help with the lowering of the rear end.
-
Your still going to lose power in your ragb.
-
Everything you pass power through robs power.. everytime power has to change direction you lose power.
Make it simple
-
We are talking driveshaft ( direct drive) like a sprinter is setup, right?
-
We are talking driveshaft ( direct drive) like a sprinter is setup, right?
sorta only no torque tube.
No, you should look thru the build section at proven driveline layouts and copy what works and is dependable
ie: 700 and cart axle or 600/820 trans axle and jackshaft
any way someone could help with the search im having a hard time
-
Thats gonna be hard with a mower orginated trans or trans axel
-
Twisted belt system simply won't hold up to the higher rpms of a racing mowchine, allow a slip clutch to work properly, and loses a good bit of hp in the twist...
I'd like to know more about this.
Why is RPM such a problem? I'm pretty sure I've seen factory lawn mower's use a twisted belt to drive the mower deck, and that see's just as high as RPM's as we do driving the wheels.
I know a slipper pullley clutch wont work, but a centrifugal clutch should.
And I'd be willing to bet that twisting a belt 90º will take a lot less power then a bevel gear set.
-
Why is RPM such a problem? I'm pretty sure I've seen factory lawn mower's use a twisted belt to drive the mower deck, and that see's just as high as RPM's as we do driving the wheels.
Not even close in rpm....
-
Not even close in rpm....
What do you mean not even close? The deck pulley off the engine is quite large, and the blade pulley small. In fact, I'm very sure that the deck belt RPM is spinning just as fast (if not faster) as some of you guy's drive belt going to the tranny.
-
Belt speed is not there if the motor doesn't go over 3650 rpm...
and decks run constant rpm not on the gas off the gas
-
Belt speed is not there if the motor doesn't go over 3650 rpm...
and decks run constant rpm not on the gas off the gas
Sure the motor pulley does'nt see any thing over 3650 rpm's, but having a 6" pulley drive a 3" pulley is over driven enough to say that the belt speed is quite high.
Deck speed is pretty constant once on, but it still needs to be engaged and disengaged.
-
I'm not sure how to do the math, but an 8" pulley on a motor turning 6500 rpm will have a way higher belt speed than a 6" mower deck drive pulley on a motor turning 3650 rpm.
-
The belt speed is determined by the engine pulley diameter and the engine speed.
I think I got it figured out. Here's what I came up with.... A mower engine with a 6" pulley spinning at 3650 rpms will have a belt speed of 95.51 feet per second. An engine with an 8" pulley spinning at 6500 rpms will have a belt speed of 226.78 :omg: feet per second. That's a pretty big difference.
Now I gotta go rest! My little pea brain is tired! :D
-
I'm not sure how to do the math, but an 8" pulley on a motor turning 6500 rpm will have a way higher belt speed than a 6" mower deck drive pulley on a motor turning 3650 rpm.
6500 @ 8" = 13606 FPM
3650 @ 6" = 5730 FPM
Not even close.
-
How many of you guy's are running a 8" engine pulley?
And, how do we know RPM is a problem for a twisted belt set up? Why is it when the belts are parallel they can spin what ever RPM you can throw at it, but if you twist one of the pulley's 90º all of a sudden 3651 RPM's will cause it to exsplode?
-
How many of you guy's are running a 8" engine pulley?
Most of us
And, how do we know RPM is a problem for a twisted belt set up? Why is it when the belts are parallel they can spin what ever RPM you can throw at it, but if you twist one of the pulley's 90º all of a sudden 3651 RPM's will cause it to exsplode?
In case you haven't noticed, some guys play heck keeping belts on a race mower.
One of the things George recently taught me, and my mower demonstrated well, is the slap you get out of a belt when you let off the gas. Basically, your pulling on it very hard, when you quit pulling on it the belt section behind the pulley has alot of stress and momentum in it and comes slamming forward. with out a good guide set-up it will throw the belt right off of a pulley. Twisting the belt would make this alot worse.You do not have this problem stock because you don't have near the stress or momentum in the belt.
And the calculation for belt speed is: Diameter of Pulley X RPM X .262
This is called Surface Feet Per Minute, or SFM. It is one of the most important calculations we use in machining and is applicable to any spinning object.
As far as twisting the belt, with the power we are putting to them, you'll twits the cords.
-
More than the math you learned in third grade..... Here is a link to a great chart that has several formulas for calculating the types of forces we deal with in building these machines. Many times what looks like it will be strong enough to do a job actually isn't because of the monumental amounts of torque, force and RPM applied to them.
-
More than the math you learned in third grade..... Here is a link to
Where is the link?
-
I see, several posts ran together, and I got distracted on this one,.
I hate when that happens :doh:
-
I see, several posts ran together, and I got distracted on this one,.
I hate when that happens :doh:
Me too...
But it does goes to show ya on one thing.... mower racing is more technical,
than just taking the governor off grandma's mower and going to race it.
We use them fancy mathiplications and stuff.