04:01:13pm, Sunday, April 28, 2024
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Thinking outside the box: New sled designs
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Moderator Registered: 07/06/2008 Posts: 1,347 |
In another thread, a poster and a modified tractor puller have had a brief exchange regarding the unlimited modified class.
The poster mentioned sleds being loaded down to the point that this class sometimes has issues putting on a good show. The mod puller and poster each had points. This prompted a thought: The sled has had the same basic design since the 1970s (maybe even a little before). Is there a design that may work better at transferring weight with today's vehicles? Is there something that looks nothing like the sleds we're used to that may be easier to adapt, have a lower towing weight even if they could carry as much or more weight than the current design? There's not a right or wrong answer, but if a puller or sled owner has ever wondered "what if somebody tried this?", what sled innovations may work better, even if they are radically different from current sleds? |
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Re: Thinking outside the box: New sled designs
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Registered: 04/04/2008 Posts: 1,522 |
More resistance,less weight.more grousers ?? |
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Re: Thinking outside the box: New sled designs
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Registered: 02/23/2017 Posts: 137 |
More bars, taller (deeper) bars, tear up the track more as a class goes on. In some types of dirt, the track goes away, on other types, it goes back together better, either way it becomes a numbers game usually.... |
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Re: Thinking outside the box: New sled designs
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Registered: 04/04/2008 Posts: 630 |
Logan,
Agreed more bars are not a good thing for consistency. To further some of the discussion about the Unlimiteds, I've felt for years that that class often doesn't put on as good of a show as some other mod classes because the sled has to be so heavy to stop them in a reasonable distance that they suffer greatly on the starting line as well as slower passes. As an operator of a sled what are you thoughts? S'no Farmer |
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Re: Thinking outside the box: New sled designs
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Registered: 02/23/2017 Posts: 137 |
Personally, I've never hooked the NTPA unlimited class, only the PPL super mod class. But yes, the more weight that has to be loaded in the wagon definitely affects how easy/hard it rolls to start off with. A trailer with 10 bales of hay pulls easier than a trailer loaded with 20 bales of hay..... |
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Re: Thinking outside the box: New sled designs
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Registered: 04/04/2008 Posts: 1,522 |
More bars tears up the track,more weight hurts the starting line and speed,raise chain some does both,lengthen chain does both,longer track limits event venues..looks like the power needs backed down a bunch |
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Re: Thinking outside the box: New sled designs
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Registered: 01/31/2012 Posts: 99 |
I've always thought that if the sled was able to preset a desired tension to the pull chain and partially propell itself for the first 75-100' it would help them not spin the tires so bad. But then that would require more weight to stop them after an easy start, probably create controversy of sled operater control, and a lot more sophisticated sled, which likely lead to more break downs |
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Re: Thinking outside the box: New sled designs
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Just Sayin’
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Let’s think a little differently, why not think maybe the promoter, in order to book the UNL class, has to have a minimum 350’ (or whatever) of workable track? Giving them more room to run & be stopped. Just an idea. It’s like they hook at your local, smaller county fair |
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Re: Thinking outside the box: New sled designs
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You said thinking out side the box. What if the chain attachment was on a movable mount that was gear driven. As the sled went down the track the chain angle changed reducing the lift on the front of the pan. Or a switch like the pan drop. When the pan dropped the chain mount moved up a few inches
H |
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Re: Thinking outside the box: New sled designs
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Tomah winner
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I'm wondering, will this only be for the unlimited class, or will it affect all classes? |
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Re: Thinking outside the box: New sled designs
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Registered: 02/17/2013 Posts: 120 |
If today’s sleds are having issues stopping the mod classes, why not lower the hitch height in the rules….? |
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Re: Thinking outside the box: New sled designs
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?
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That would be the simplest and easiest and by far the cheapest route to take !!! I agree on that concept !!!! |
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Re: Thinking outside the box: New sled designs
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Registered: 09/10/2017 Posts: 60 |
Possibly make the grousers progressively engage as the box nears the top. This would make for a smoother more controlled stop and could be tied into the sled mechanically. |
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Re: Thinking outside the box: New sled designs
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Registered: 02/23/2012 Posts: 542 |
Look at the hillbilly deluxe sled in Kentucky he runs something different in his air bags that makes it more progressive of a stop
It’s the smoothest sled I’ve ever hooked but he can still stop ya |
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Re: Thinking outside the box: New sled designs
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Had it ever happened that someone built a sled with a progressive box movement? I mean, for instance the basic velocity where is the sled is working totally linearly, with the box each run at e.g. 270' at the front, shall be 0-15mph. And for each bit of additional velo a kind of cvt drive (vario-matic?) makes the box faster. In such a way that if the weighted average mean speed is e.g. 20mph instead of 15, the box already reaches the rails front end at 250'
Equivalent to 25mph could be 230' etc. With a main gear set of lets say 5-8 diff basic settings, and superposed with that non-linear velo contribution. Had someone ever tried such a mech? Or is it undesirable at all? |
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Re: Thinking outside the box: New sled designs
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Paull
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Sounds practical, and very common sense,same principle as the weight box coming ahead of the wheels and then ahead of the pan pivot. |
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Re: Thinking outside the box: New sled designs
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Registered: 01/23/2011 Posts: 241 |
How about a traction dynamometer, with computer controls you could make the load curve as you wanted. |
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Re: Thinking outside the box: New sled designs
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Well RCP, basically that would be the simplest way to get the mentioned result. But I would rather choose a traceable mech sys instead of some computer stuff, because of a) transparency to avoid suspicious voices in terms of cheating , b) to have something that could be maintained easily with hammer, torch and wrenches instead of specialists for IT or mechatronics.
The thing with transparency is not just only for the competitors amongst each other, avoid doubts etc, it's furthermore to make it somehow visible for the fans in the grandstands what actually happen during the individual pull, that they can notice somehow the relation of a significant increased speed and a sooner arrived box. With a traction dynometer as a black box, this relationship never could be made visible. The only computer stuff I like to suggest is to have an adequate monitoring system of the things that happen in real-time inside the sled. Place a screen under a pavilion in the pit area, where competitors and/or other teams can see the individual graphs of the current class with respect of sled speed, pulling distance and box movement. Provide the ability to get this info/data as PDFs as well. And whom it concerns can aftermath this stuff, review the results, cross-check with equations and after a while feel pretty confident that there is no cheating inside. If you like, call it a confidence-building measure. And by the way, to achieve this offer, this could be a task for younger people which are eager to help with their computer/IT/mechatronic skills. By the way, the vehicle of the picture seems to be a modified version of the famous MAZ 535, prepared for research purposes. Normally this front attached tow bar was applied for the vehicle to use it as a push-tractor. In combo with another MAZ tank trailer tractor (537) it was used to push/pull icbm missile trailers. The engines of this tank trailer tractors of the MAZ factory (minsk avto zavod) are pretty much the same as in the common soviet main battle tanks (Transmash W2 / D12A2 525 , Diesel V12, 2373 cu.in.) , from 1940s (T34) until 2000 (T90). Basically I disbelieve that this kind of "wheel-based" traction dynometer is suitable for tractor pulling purposes beyond a particular power level. The expected travel speed will quite soon exceed the given capabilities of such a thing, with the results that it will start hopping, bumping etc and probably will just fall apart. If at all a traction dynometer vehicle, then it seems necessary to choose a tracked vehicle basis. |
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Re: Thinking outside the box: New sled designs
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Registered: 01/23/2011 Posts: 241 |
The advantage of being computer controlled, is the load could be reviewed after the pull to determine if things were done correctly. Accusations of cheating by sled operators is nothing new and having only mechanical systems does not eliminate those accusations. |
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Re: Thinking outside the box: New sled designs
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Registered: 08/27/2019 Posts: 212 |
Nabraska uses such a vehicle to test tractors, and pretty large and heavy ones at that.
I'd say one could stop anything , right up to super stock or unl. mod with no problem. I't would be interesting to say the least and probably more expensive i'd assume. |
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Re: Thinking outside the box: New sled designs
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Sounds interesting to me. Would be fun to do a research test campaign, first measure some typically sled runs on real pulls, then simulate them with that traction dyno. After validation of "are the measured runs reproducible?" it is a basis to perform parameter studies, in terms of hitch settings, tire choice etc, or even with non-linear box movement choice. The only thing that needs to be at most reliable is the pulling vehicle. I guess that the wear&tear on a typically unlim mod is to expensive to repeat several runs with different settings. Only possible choice: turbine powered mods. But I assume that they are not really representative in terms of general pulling behaviour, drivability etc. |
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Re: Thinking outside the box: New sled designs
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What would be really cool and I'm surprised no one is doing this would be to put a strain gauge on the hook of the sled and measure the tension force in pounds. This would be really interesting for the fans to see on a big screen because it would show them clearly the difference between the classes when it comes to how much the sled is loaded and working against the puller. it would also be of great interest to the pullers to see the force plotted by distance to see how the shape of the curve as the force is applied. It would be different for every track. To really know something you have to measure it and you have to do that before you can make any type of real innovations.
Mike |
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Re: Thinking outside the box: New sled designs
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I agree, that would be a real eyeopener for many people. And we would get rid of the phrase "hot farm seems to be of comparable power alike unlim mods because they are going as well 280-320' with partially 25-30mph" , if people can see these numbers which reflects the true physics at the chain. |
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Re: Thinking outside the box: New sled designs
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Registered: 02/17/2013 Posts: 120 |
Took a bit to find it. They no longer make it apparently but I thought it was a neat idea. [www.bamberengineering.com] |
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Re: Thinking outside the box: New sled designs
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Registered: 08/27/2019 Posts: 212 |
That link no longer works , or goes to what your referring to....at least on my end anyway. |
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Re: Thinking outside the box: New sled designs
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Registered: 02/17/2013 Posts: 120 |
Correct, thats the reason why I said “they apparently don’t make it or sell it anymore”, all the link was meant to do is let ppl know something similar was made and if you really want more information here’s the link to get to their website to email or call them. Instead of a hook with a strain gauge, it was a tractor drawbar for say a Haslag hitch and you hook it to you data logger …..if you DuckDuckGo or google bamber hitch sensor you can read a very little bit of the description of that product they sold. Edited 1 time(s). Last edit at 04/14/2022 07:21AM by IHFarmer07. |
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Re: Thinking outside the box: New sled designs
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Yes, very cool, but would be much more interesting to have it on the back side of the chain on the sled, so you could compare runs within and between classes.
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Re: Thinking outside the box: New sled designs
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Registered: 04/04/2008 Posts: 1,522 |
I like the idea of a strain guage to.be of interest to everyone,esp with a good announcer |
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