Curious... Why a RPM limit???

[PullinPrairieGold]

I know that pulling clubs all over try, & have a very hard time policeing RPM limits... I am very curious to why you need a RPM limit, when you have a speed limit???? does anyone have a serious answer to my question????

 

[1945GMPULLER]

SAFETY!!!!!!!!!!!!!!!!

 

[deereabhm]

F = mv^2 / r

I'm not 100% sure, but I'm fairly certain that as velocity increases the force on the flywheel is squared..... An old cast flywheel isn't designed for high rpms. Ever seen a flywheel explode.. not pretty

 

[770]

You have never seen a flywheel explode, have you. It"s not pretty, especially for people within the immediate vicinity. Parts can fly over 100"+ easily. A lot of clubs mandate steel flywheels for certain classes that turn higher RPM"s.

 

[A.P.]

You might want to check out these photos for results of a flywheel explosion.
http://www.pulloff.com/phorum/file.php?2,file=3586,filename=deere_in_half_2.jpg

http://www.pulloff.com/phorum/file.php?2,file=3585,filename=deere_in_half.jpg

 

[Anonymous-0]

a friend cut a 900 Case in half, well not completely in half,the temp sender was still connected! The clutch housing and flywheel were gone!

 

[jd b puller]

To reduce the chance of one redneck killing another.

yeah, I know, you'll still have the "Hey ya'all watch this" issues with chainsaws and knives.

 

[Anonymous-0]

ah he** that tractor was took apart. dont need no da*m rpm limit

 

[Marbarger farms]

I was at that pull. It was very scary when that flywheel let loose!!! A 15 lb chunk went throught the wrought iron fence and in to the base of the grandstands! Noone but the driver was hurt, and only a busted leg. Talk about god watching!

 

[Lamont]

And I thought there was no such thing as a DUMB question!

 

[johns]

I think this is a good question, in farmstock with a 3/3.5mph limit how high can you really get the rpms before your over the speed limit? Also guys that run open class should be required to have a scatter blanket and I would think if they are serious about pulling they would've balanced the engine and taken other durability issues(like using a steel flywheel instead of cast) into consideration.

 

[JD hauler]

Yes, good point, alot of guys are 3 ft thick on this one, in the brain that is.

 

[1970-1655]

I was at a pull at a state fair several years ago and a flywheel let go. People started checking and no injuries in the stands. But a lady was waiting in line at the food stand outside the track. She got a large chunk of the flywheel in the face. Never knew what hit her. The tractor driver never pulled again and even any mention of pulling tore him up. He was always safety conscious and checked everything twice.

If horsepower and/or rpm has been increased at least 25% and used for pulling, for me, I will be running a steel certified flywheel and clutch as well as a blanket. I do not want that on my conscience the rest of my life.

 

[Anonymous-0]

fact-if rpm's are doubled centrifical force trying to tear apart the flywheel quadruples!

 

[Mopower]

I'll try to be as serious and intelligent as possible. Sometimes that is a tall order. I tend to agree with you regarding many rules in speed limit classes. RPM limits are usually created for safety. I have often wondered about setting a 2500 or 3000 rpm limit for all tractors. In a speed limit situation I think this would allow maximum participation and engines of many sizes.

However, mechanical limits of antique tractors vary. A 2500 rpm 2 cylinder Deere would scare me. Not that it can't be built to do it (I know guys that can), but not everyone will. This is where the foggy gray area of "fairness" creeps in. Do we set one limit for everyone and a lower limit for Deere? I'd say sure, but Deere guys will holler. Some Fords ran 2500 minimum. Their engines could stand much more.

Intelligently, I have no fair solution. Speed limit is a great equalizer. Open class rules should probably be more restrictive than speed limit because of this.

 

[jdeereg]

My only comment relating to this discussion is that all safety equipment should be in place to run in the "open gear" classes. If a tractor has the minimum thickness side shields, a scatter blanket, steel flywheel, working kill switch, etc., it should be allowed to turn a little more. I realize that a 2500 RPM two cylinder is dangerous, but why not allow the tractors to turn over 30% of the factory rated RPMs. Maybe 40% or even 50% with a cap of 3000-3500 RPMs. We don"t want to get anybody hurt, especially ourselves. We just want to be able to get the performance out of our tractors.

 

[PullinPrairieGold]

I was assuming that any one who spent the time & money to build a tractor capable of turning these higer RPM's Would use a steel flywheel, scatter shield blanket, & any other safety equipment to keep any & all safe.... seems to me that most of the arguments arent over the safety aspect, but over the performance aspect...

 

[PullinPrairieGold]

No, i've never seen a tractor flywheel come apart, but i,ve seen plenty of race cars do it... very dangerous.... lots of people been hurt that way.. i realize antique tractor pulling should be a safe motorsport, but any one participating in any motorsport is at risk... i've seen several fans come apart & sling blades to who knows where... & RPM's didnt have anything to do with it...

 

[Mopower]

Sounds quite fair to me. I've seen some wild stuff screaming. It was wrapped up tight!

 

[oliver_man]

once you see a fly wheel break off and roll down the track you"ll know why theirs rpm limits

 

[buickanddeere]

Because taking an engine with a 1400rpm redline to 1980rpm doubles the stress on the flywheel/clutch/fan etc.
How lucky do you feel with somebody else's life?

 

[showcrop]

It appears to me that your question is about competition and maybe 10% variations in RPMs for pulling advantage, as opposed to serious RPM increases and potential mechanical failure. And as you point out high RPMs and successful speed limit pulling are pretty much mutually exclusive. Am I right?

 

[CoopertownBob]

RPM limits are for safety reasons. Just because you, me and twelve other guys are safety conscious and build our tractors to all the proper safety specs, doesn't mean some ya-hoo just starting out will. Then, there is always the people with what I call the "just a little more" syndrome. You know the ones, they think that if it all held together at 3000 RPM, then they need to try 4000 next, if it holds, go to 5000, and so on. Next thing you know, some guy pulls onto the starting line with a 1939 H Farmall attempting to turn 10000 RPM and still running the original cast crank in it! It is just like Forrest's momma said, stupid is as stupid does.

As for me, I run stock RPM classes, period. I don't even like to be around tractors that pull at 20% over, let alone 3000 or more!