Hydraulic Dune Buggy Design: Is My Math Correct?

In summary, the conversation is about a project involving building a hydraulic-driven dune buggy vehicle. The participants are seeking help with the design and component selection for the vehicle, which will operate with two handles for steering and a gas pedal for control. Questions are raised about the math calculations and the accuracy of formulas for determining motor size and power requirements. The participants also discuss the potential challenges of steering at high speeds and the cost of using wheel hub motors. It is clarified that the vehicle will be strictly for off-road use.
  • #1
larkinja
63
0
Hi all. I don't know if I have posted this in the right section, but I am hoping someone might be able to lend me a hand with a project.

A friend on mine and I are always looking to build something challenging and unique. We recently finished building a truck completely from the ground up, designing all our own parts (besides engine, tranny, etc..) Anyway, inspired by our commercial lawn mower and our bobcat, we would like to build a hydraulic driven dune buggy-ish looking vehicle. Many have asked why, and the answer is simple, its something different and we would like to learn more about hydraulics in the process. I have researched power requirements, done many of the formulas, but I am having a tough time translating data into the real world. In other words, will it work)

My DATA:

Vehicle Mass - 2000lbs
Maximum Speed - 70mph
Maximum Incline - 20degrees
Wheel Radius - 13"
Axle Ratio - 2.5:1
Rolling Resistance - 0.037

With these values, I have concluded this:

Drawbar Pull - 758
Wheel Torque - 9854.524 in/lb
Motor Torque - 3941 in/lb
RPM - 2261rpm
Power Required - 141hp

If I calculate based on 3000psi system and 4 drive motors I get:

Flow Rate - 80gpm
Torque on each motor - 985 in/lb

Concluding a minimum motor size of 2 cu in/rev motor

Now for my questions. 1st, is my math correct? I did this all on paper, then created a spreadsheet that solves all the equations so I can change the variables to meet the end goal.

2nd question, am I going about this the right way. Where my confusion lies mostly is in the motors and pumps. The math does not seem to match manufacturers specs for there motors. So is a formula not accurate enough given the different types of hydraulic motors?

I am wondering if there is anyone out there with any hydraulic experience that can point us in the right direction. Maybe with component selection, and even possibly helping us coming up with the schematic.

We are just starting the research, so any suggestions would be helpful. Do don't want a traditional steering wheel. We want it to operate with two handles just like the commercial mower works. Both handles forward it goes straight. Left handle up, steers right, handles back, reverse. A gas pedal to control engine speed. Currently the thought is one motor for each wheel. Front left and rear left on the same circuit. Same with the right side. Front wheels would be on steering spindles, tied to each other, but left to free steer. Possibly use stabilizers to help with hitting bumps and ruts and returning to straight. This would just be a concept to test, don't know if it would steer well that way or not.

I am still looking for the best method for braking. On the mower, you just easy back on the handles and it stops. If you let go of the handles, it comes to a abrupt stop. Which I don't think would be very safe at higher speeds. Maybe at valve center, a bypass which allows the wheels to free spin, and then use traditional braking. I have read about using accumulators for hydraulic braking. I don't care about fuel efficiency, this isn't a car, which it what this is used for such as the UPS test truck.

Anyway, this post has gotten long enough. If anyone wants to give me a hand I would be very grateful. And just so everyone knows, this is not a design for a commercial vehicle, just boys and there toys, so let's not think in terms of production.

Thanks again,

Jason
 
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  • #2
You mention 4 drive motors which implies wheel hub motors. 70 MPH is not in your budget. Have you researched the cost of wheel motors and the planetary systems that go along with them?
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Oh I just reread your post. Front wheels are simply on casters at 70 MPH? Steering a vehicle with a zero turn radius at 70 MPH can't be anything but, well, I can't think of words other than crazy, impossible, etc. BTW, what you describe IS a zero turn radius vehicle even if you hadn't mentioned it specifically.
 
  • #3
Actually, I wasn't thinking wheel hub motors. I was thinking stationary motors, with a gear reduction box, and a cv shaft to the wheel hubs. The question more is do you use a high rpm motor with a gear box, or a motor that already has gear reduction that already has the appropriate rpm out put to be couple directly. Either way, I was thinking of mounting a motor to the frame and using a cv shaft. This eliminated side load, etc...

As far as the steering, no I am not after zero turn. Zero turn would allow a direct pivot of the vehicle. I don't need or even want that.

As for 70mph, I realize that may not be practical, just a design consideration. The ideal speed would be more in the 40-45 range. But just because the wife's minivan can go 130mph, doesn't mean you should.

Also, please I am looking for some help with the design, not just a "you're crazy" response. I can get that from the wife anytime.

If anyone has an application suggestion, or any specific components in mind please let me know. Or even an engineering firm that won't charge a fortune to draw something up.

Thanks again
 
  • #4
Also, one additional note. This is in no way going to be driven on any road. This is strictly an off-road vehicle.
 
  • #5
I was in a hurry when I posted earlier today. You mentioned 4 drive motors. You mentioned that the front wheels will caster. So it's obvious to me that the 2 back wheels are driven off of one hydraulic motor each(that's what you said), but then where will the other two motors be used? You mention that you intend to steer the vehicle by allowing the front to caster freely (no problem with that, at low speeds anyway) and varying the speed to the back wheels to pull one side around more than the other. No problem there either. If you intend to drive the vehicle with CV joints and a drive shaft, I would then assume you don't intend to drive the front wheels? This is the reason I asked what you intend to do with the other two hydraulic motors. The reason I assume you don't intend to drive the front wheels is because if you allow them to caster freely how will you attach a driveline to them? Think about this. There are several reasons why vehicles use hydrostatic drive. 1) Infinitely variable speed. 2) Difficulty getting power transmitted to the wheels with conventional drive shafts. 3) Zero turn radius. By using two hydraulic motors to drive the back wheels along with CV joint drive shafts you are proving that you DON'T need hydrostatic drive because of my reason #2. You stated that you didn't want zero turn radius so you have eliminated reason #3. Is reason #1 that important to you?
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Have you priced hydraulic motors with a built in gear reduction? I have, but it was a wheel motor. Expect to pay between $5000 and $10,000 for just one.
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I see this project as a worst case. You are accomplishing things by using the least cost effective design.
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So, to wrap my post up, please elaborate on what you intend to do EXACTLY. I want to know what you intend to do with the front wheels castering and if you intend to drive them. I personally can't imagine freely castering front wheels even at 30 MPH.
 
  • #6
Torque is measured in Newton-meters, or Lb-force feet, not in in/lb.
Power (watts) = HP/746 = torque (N-m) x 2 pi RPM/60
Bob S
 
  • #7
Sounds like a fun project. But extrememly challenging. Fluid power has been my occupation for the last ten years. There are many reasons you do not see hydrostatic buggies running around.

Your math is correct on the flow and pressure required to get 141HP. But, being a mobile application using an internal combustion engine you are going to need 200+ HP motor. The reason for this that with an electric motor varying loads are instantly met by an increase in current. A combustion engine cannot react to loads by increasing fuel consumption quick enough so the engine needs to be oversized to accommodate load changes. Rule of thumb is 2x theoretical HP required.

Basically, take that engine out of the truck you built and put it in the buggy. That will be the easiest part of the project.

You won't want to regulate the speed of the engine. You want this to maintain an optimum RPM to accommodate the loads. You simply want to control flow to your motors to control your speed. There are a couple of ways to do this but let's say we do it at the pump swash plate.

Now we have to determine the pump configuration. Are we utilizing a single variable displacement pressure compensated pump (with overcenter swash plate capability for a reverse function) or one for each motor? If we utilize one for each motor we have a few options for pump mounting. We may be able to stack them inline or mount them on pump drives, something like this: http://www.twindisc.com/IndustrialProducts/IndustrialPumpDrives.html" [Broken].

If we use a single pump, which would be more efficient from the pump side of things, it's pretty easy. The problem is prioritizing flow to your motors. Oil will go the path of least resistence. If a wheel somehow sees no load, let's say it caught some air going over a bump, all your oil is going to want to go towards that wheel causing an immediate drop in power to the rest of the wheels. To counter this we need to introduce a flow divider. This will require some research. You will want a configuration that is accurate but has enough play that when you turn your inside wheels won't be fighting with your outside wheels. Kind of like an old school 4wd dif.

Braking, this will be touchy. Feathering the brake won't be so easy. But I'll continue after I hear what you think so far...
 
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  • #8
larkinja said:
Actually, I wasn't thinking wheel hub motors. I was thinking stationary motors, with a gear reduction box, and a cv shaft to the wheel hubs. The question more is do you use a high rpm motor with a gear box, or a motor that already has gear reduction that already has the appropriate rpm out put to be couple directly. Either way, I was thinking of mounting a motor to the frame and using a cv shaft. This eliminated side load, etc...

As far as the steering, no I am not after zero turn. Zero turn would allow a direct pivot of the vehicle. I don't need or even want that.

As for 70mph, I realize that may not be practical, just a design consideration. The ideal speed would be more in the 40-45 range. But just because the wife's minivan can go 130mph, doesn't mean you should.

Also, please I am looking for some help with the design, not just a "you're crazy" response. I can get that from the wife anytime.

If anyone has an application suggestion, or any specific components in mind please let me know. Or even an engineering firm that won't charge a fortune to draw something up.

Thanks again[shaft connection and gears]
 
  • #9
Thank you so much for the reply. Yes, I do full understand it is a challenge. From a financial standpoint I can definitely see why you wouldn't see this as a norm, but I have found a few people that have done it, so I see encouragement in that.

The horsepower requirements shouldn't be a problem. We have several engines we can use for this project. I have a basically stock 350ci engine that should do 240hp easily. The challenge I see is that most pumps seem to have a limit of 2-3k rpm and a gas engine makes its peak around 4000, so I will have to find the hp curve and see if it will still make enough power at lower rpm.

As for the pump. A single displacement motor seems to be the most cost effective, but I see this as being a problem at slower speeds not having enough torque. It seems that the pump would have to be extremely oversized to make up for the torque at slower speeds. A variable displacement pump seems to be a better fit, although more expensive. However I have seen used ones that are reasonable. What are your thoughts on this. Am I thinking right on this?

I think you might be right on the braking. I'm now thinking that maybe a relief valve or someway to free spin the motors when pressure is removed and just using traditional disk brakes. If I stick with the auto spindle and hub, that wouldn't be a problem at all.

As for the traction issue. I am definitely going to need some help with that. I have heard of a couple ways of doing this. I have heard of using a manifold or valve of some sort that would allow free flowing fluid as you described. Would that be parallel? Then you could flip a switch or push a valve and it would redirect to a series flow "locking" all motors together for full traction. I may be mistaken, but doesn't some heavy equipment do something like this. We rented a case backhoe last spring at it had a function like this?

As for the motors, the math seems to say that the motors don't have to be all that big. Based on my math in the first post, these can be had for a few hundred buck each, maybe less used or from a surplus industrial store. Don't know if you have any experience in these types of parts.

I do realize this may seem like something not worth the effort, but myself it's more about the challenge. I like learning about new things and trying new things. To many people spend their life in a "comfort zone". But think about the advantages this affords if it does work. At least from a custom vehicle build standpoint. No longer does the engine have to be in one exact spot. Rear transaxle transmissions that can take 240hp are very expensive. Less expensive transaxles have a short and long side for axles which limits the travel on the suspension. CG can be fine tuned since components can be placed anywhere. Not to mention making the buggy 4 wheel drive is near impossible without custom tranfer cases. This buggy could easily cost $15000 to build with 240hp, rear engine, and 4 wheel drive, maybe more. Heck high performance rear tranaxles can cost $10,000 alone. So maybe now what I want to do doesn't sound so bad?

I guess the real question comes down to, can a hydraulic system provide both power and speed realistically. I know I stated 70 mph, but more important to me would be acceleration. Most of the driving would be in the 0-40 mph range, high speed I guess would be a luxury, since most of my builds do both it is hard to think on not having it.

Hopefully this gives a clearer picture. And again, I want to thank you for any help you can provide. Let me know if there is anything I can do in return.

Jason
 
  • #10
Get back to you tonight Jason. We can start building a conceptual schematic.
 
  • #11
To start with hydrostatic drives are not nearly as efficient as mechanical drives. As for brakes you could look into recovering some of it. Research hydraulic hybrids.
Chapter 6 in this book has information on hydrostatic drives and he works through an example:
http://www.scribd.com/doc/10512227/Fluid-Power-Circuits-and-Controls-Fundamentals-and-Applications [Broken]
This website has members that build hydraulic drives:
http://www.hydraulicinnovations.com/
 
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  • #12
Thanks drankin, I look forward to your ideas.

I like the flow divider idea. If we can make it so it doesn't get the open differential effect on loose ground, maybe I will forget the steering concept. Maybe instead use the hydraulics for hydraulic steering. Maybe using a joystick method. Forward on the stick makes is go forward, the side to side movement could control the hydraulic steering, the way a skidsteer works, although I'm thinking of it more like a fighterjet! :)

Anyway, I can't wait to hear your thoughts.
 
  • #13
larkinja said:
Thanks drankin, I look forward to your ideas.

I like the flow divider idea. If we can make it so it doesn't get the open differential effect on loose ground, maybe I will forget the steering concept. Maybe instead use the hydraulics for hydraulic steering. Maybe using a joystick method. Forward on the stick makes is go forward, the side to side movement could control the hydraulic steering, the way a skidsteer works, although I'm thinking of it more like a fighterjet! :)

Anyway, I can't wait to hear your thoughts.

How big are we talking?

Full size buggy or skid steer size? This will determine how we steer. Turning the front wheels or opposing?

There are a few ways to design this circuit but I'll need a little more of an idea of what it's supposed to look like. The trick is how to drive the wheels in a way that's efficient and doesn't let the motors self destruct by way of intensification or cavitation.

I suggest going with something on a smaller scale. It could be a 4x4 ATV with crazy torque and climbing performance. :) Then graduate to something larger.
 
  • #14
The current frame we have now is a little smaller than a full size buggy. The original concept was to make it as small as possible, but the width of the drivetrain we were going to use dictated it's width. The drivetrain came from a Pontiac Fiero, so if you've seen one of those recently, its about that size. The frame itself doesn't weigh that much, currently less than 200lbs. We can definitely make weight a top priority. I used 2000 lb for my numbers. Somewhat of a guess. It is designed for two seats, so figure 400 lb for people, another 200lb for seats and misc.. The variables are engine/pump/motor weight since we don't know what those are yet. The 350 weighs 520lbs, plus whatever pump we choose, 4 motors, and the oil tank and of course gas tank, brakes, wheels, and tires.

Can some sort of large oil cooler be used to cut down on the size of the oil tank? This could help save weight, but I don't know anything about that end of it yet.

Definately bigger than an atv, more like a offroad go-kart on steroids I guess.

The ideal operating range would be in the 0-40ish mph range. But if possible I would like the ability to go faster. I read once about someone who had some sort of valve that would allow in one position fluid to go to all for wheels with higher torque and a top speed of 45, then could move a valve and divert all the flow to the rear wheels giving him more top end. I don't know if that makes sense or is even really possible, but sounded like a good idea.

I guess to sum up, I would like to use the frame I already built. If it is really THAT bad of and idea, I can shelf that and start over with the frame, although I would rather not.

Are you recommending a smaller size to start with based on component cost, or complexity, or something else? If it's just purely cost, then let's design it so I can start looking for parts. It it just becomes to expensive, then that will tell me we have to go smaller. Honestly most of the size is based on being a 2 seater. I don't want a single seater. To be honest, if this one worked, I was going to contemplate a 4 seater next.

Hope this helps, let me know what else your thinking.
 
  • #15
larkinja said:
The current frame we have now is a little smaller than a full size buggy. The original concept was to make it as small as possible, but the width of the drivetrain we were going to use dictated it's width. The drivetrain came from a Pontiac Fiero, so if you've seen one of those recently, its about that size. The frame itself doesn't weigh that much, currently less than 200lbs. We can definitely make weight a top priority. I used 2000 lb for my numbers. Somewhat of a guess. It is designed for two seats, so figure 400 lb for people, another 200lb for seats and misc.. The variables are engine/pump/motor weight since we don't know what those are yet. The 350 weighs 520lbs, plus whatever pump we choose, 4 motors, and the oil tank and of course gas tank, brakes, wheels, and tires.

Can some sort of large oil cooler be used to cut down on the size of the oil tank? This could help save weight, but I don't know anything about that end of it yet.

Definately bigger than an atv, more like a offroad go-kart on steroids I guess.

The ideal operating range would be in the 0-40ish mph range. But if possible I would like the ability to go faster. I read once about someone who had some sort of valve that would allow in one position fluid to go to all for wheels with higher torque and a top speed of 45, then could move a valve and divert all the flow to the rear wheels giving him more top end. I don't know if that makes sense or is even really possible, but sounded like a good idea.

I guess to sum up, I would like to use the frame I already built. If it is really THAT bad of and idea, I can shelf that and start over with the frame, although I would rather not.

Are you recommending a smaller size to start with based on component cost, or complexity, or something else? If it's just purely cost, then let's design it so I can start looking for parts. It it just becomes to expensive, then that will tell me we have to go smaller. Honestly most of the size is based on being a 2 seater. I don't want a single seater. To be honest, if this one worked, I was going to contemplate a 4 seater next.

Hope this helps, let me know what else your thinking.

200lb frame seems light but the size will work fine. I like the rear wheel drive mode idea. That's easy enough to include.

Need you to find a rotating joint setup that allows the wheel to "free-wheel" so that the motor can't be driven by the wheel. Like a ten-speed bicycle, you propel pedaling forward but free-wheel pedaling backwards. That will simplify the circuit and protect the motors. This will also allow us to go faster. If the free wheel mode can be engaged/disengaged then that solves our reverse function.

If we make the circuit closed-loop we won't need a large reservoir, just a decent size cooler. Open-loop would require a larger reservoir which we don't want sloshing around while climbing/descending/turning at speed.
 
  • #16
This free-spiining joint, is this something you have heard of, or an idea? I don't even know what you would call that. Is there an application that uses something like is? Otherwise, I do like that idea. Let me know, and I will start looking for something like that.

Jason
 
  • #17
larkinja said:
This free-spiining joint, is this something you have heard of, or an idea? I don't even know what you would call that. Is there an application that uses something like is? Otherwise, I do like that idea. Let me know, and I will start looking for something like that.

Jason

Start looking. I'm not as familiar with automotive type parts as you might be. Don't know if this would even be an automotive type part but you might recognize something that would work in this fashion.
 
  • #18
drankin said:
Start looking. I'm not as familiar with automotive type parts as you might be. Don't know if this would even be an automotive type part but you might recognize something that would work in this fashion.

Ok, I'll see what I can find. Thanks!
 
  • #19
Is there a way do do this with fluid? Maybe a a valve that allows the fluid to free flow through the motor? I haven't had to much luck finding any application that would use something like a free sprinning joint. At least something that is strong enough to handle the torque and abuse. I'll still keep looking though.

Let me know if it is possible.

Jason
 
  • #20
larkinja said:
Is there a way do do this with fluid? Maybe a a valve that allows the fluid to free flow through the motor? I haven't had to much luck finding any application that would use something like a free sprinning joint. At least something that is strong enough to handle the torque and abuse. I'll still keep looking though.

Let me know if it is possible.

Jason

You will need to make one or two changes maybe, but look at the inside of an automatic transmission torque converter, the stator clutch is a slip design that freewheels in one direction and locks up in the other direction, they transfer a lot of torque.

Ron
 
  • #21
RonL said:
You will need to make one or two changes maybe, but look at the inside of an automatic transmission torque converter, the stator clutch is a slip design that freewheels in one direction and locks up in the other direction, they transfer a lot of torque.

Ron

That's a good idea. I can check into that and see if there is a way to make it work. I think I have an extra one laying around.
 
  • #22
Ok, here is a rudimentary schematic that we can begin to build on. It just shows the hydrostatic pump unit and drive motors in parallel. That will change as we add flow dividers and the rear wheel drive "hi-speed" mode.

It's been a few years since I've worked on hydrostats but I know we can oversize the make-up pump that's attached to the main pump to accommodate pilot operated controls for footpedals and joysticks as well as auxillary hyraulics for a winch or some other function we might come up with.
 

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  • #23
Excellent. I do have a question. We have been talking about a free-wheeling design, but how do we do reverse then?

I took a look at the schematic. I will have to go and find a chart to understand the symbols, but I have a pretty good idea of the concept.
 
  • #24
How hard would it be to design it around a free flowing neutral instead of a mechanical free spinning idea? I think I figured out a way it may work, but it will be kind of bulky. It seems like reverse would be easier then, but I could be wrong.
 
  • #25
larkinja said:
How hard would it be to design it around a free flowing neutral instead of a mechanical free spinning idea? I think I figured out a way it may work, but it will be kind of bulky. It seems like reverse would be easier then, but I could be wrong.

Ideally, we would be able to free-wheel if a wheel began to spin due to turning or just flow discrepencies. Then we could switch off free-wheel in order to lock all drive motors to the wheels for reverse function. If we can't do this I'll have to add more hydraulic circuitry to protect the motors. Not a big deal, it would just be better for long term wear on the motors.
 
  • #26
I think there are going to be difficulties doing it mechanically. The torque converter idea is good, but the rpm difference may pose an issue. The speed at which it "locks" may never be reached as the rpm of the shaft coming off the motor is lower than what a torque converter is designed for.
 
  • #27
larkinja said:
I think there are going to be difficulties doing it mechanically. The torque converter idea is good, but the rpm difference may pose an issue. The speed at which it "locks" may never be reached as the rpm of the shaft coming off the motor is lower than what a torque converter is designed for.

There are low-speed-high-torgue (LSHT) rotary piston motors that have a free-wheel function available, but they are much more expensive (x10 probably) than the gear motors you wanted to use. We'll just go with hydraulic free-wheel.
 
  • #28
drankin said:
There are low-speed-high-torgue (LSHT) rotary piston motors that have a free-wheel function available, but they are much more expensive (x10 probably) than the gear motors you wanted to use. We'll just go with hydraulic free-wheel.

OK, sounds good. What else do you need from me?
 
  • #29
larkinja said:
OK, sounds good. What else do you need from me?

About $3500 as a retainer. :) j/k

Just patience. I don't have a lot of time to put into this but I'll be adding to it every day to every other day or so.

You should be looking at mounting the motor and making sure we have room behind it for the shaft couplings, bell housing, and hydrostat pump.

Do you have a picture of the frame you can put up?
 
  • #30
:) Gotcha. No Problem. At this point I am just need to figure out what size pump, motors, etc.. and like you said figure out how much space I am going to need.

I'm not sure if I have any current pictures, but I will be out there working on it Thursday, and I will get some and put them up.

And again, I REALLY appreciate everything. Any don't worry, I will be patient.

I'm not sure what I can do in return. I own a sign company, so if you ever need any signs, decals, banners, etc... let me know.

Again, thanks.
 
  • #31
I just read through this thread. Wish you had posted a few months back because an old friend of mine that died recently built an all-hydrostatic drive vehicle about 30 years ago. It was a tube-framed buggy with big wheels and all-wheel drive. He made it so that he could go fly-fishing in places that normally you'd have to walk to, wade through mud, ford streams, etc. Clever guy. He made custom gold jewelry using the lost-wax method, crafted some of the nicest hunting knives I've ever handled, and retrofitted Winchester lever-action carbines and rifles to shoot common handgun ammunition. It would have been a good excuse to get back in touch with the old genius and see what problems he ran into when making his buggy.
 
  • #32
turbo-1 said:
I just read through this thread. Wish you had posted a few months back because an old friend of mine that died recently built an all-hydrostatic drive vehicle about 30 years ago. It was a tube-framed buggy with big wheels and all-wheel drive. He made it so that he could go fly-fishing in places that normally you'd have to walk to, wade through mud, ford streams, etc. Clever guy. He made custom gold jewelry using the lost-wax method, crafted some of the nicest hunting knives I've ever handled, and retrofitted Winchester lever-action carbines and rifles to shoot common handgun ammunition. It would have been a good excuse to get back in touch with the old genius and see what problems he ran into when making his buggy.

Sounds like quite a guy!
 
  • #33
larkinja said:
Sounds like quite a guy!
Very smart. He was about the first guy around to learn the ins and outs of VHF antenna sensitivity and directionality, and apply it in this very hilly rural area to help people get TV back in the '50s. He had a very successful TV antenna business when I was a kid, and he kept enough stock on hand to demonstrate on-site what they could expect with antenna A vs antenna B or C. Hell of a businessman.

His buggy was not fast IIR, but it could get him into places that Jeeps could not go, and he had a hydrostatic-drive winch to haul himself out if he got mired. The buggy was a two-seater with an over-head pipe rack to carry a canoe. He and his son had good times with that, I'm sure.

He was a very clever and artistic guy. One time when I dropped in he was carving a red wax positive model of a ring for a very prominent man in town. The guy's daughter had commissioned the ring to reflect her father's activities in the Masons, the Shriners, the Rotary, Lions Club, and other social organizations. I never saw the finished project, but it must have brought a smile to the old guy's face when he got it. The mold looked a bit busy, but well-organized. Val's work was top-notch.
 
  • #34
turbo-1 said:
Very smart. He was about the first guy around to learn the ins and outs of VHF antenna sensitivity and directionality, and apply it in this very hilly rural area to help people get TV back in the '50s. He had a very successful TV antenna business when I was a kid, and he kept enough stock on hand to demonstrate on-site what they could expect with antenna A vs antenna B or C. Hell of a businessman.

His buggy was not fast IIR, but it could get him into places that Jeeps could not go, and he had a hydrostatic-drive winch to haul himself out if he got mired. The buggy was a two-seater with an over-head pipe rack to carry a canoe. He and his son had good times with that, I'm sure.

He was a very clever and artistic guy. One time when I dropped in he was carving a red wax positive model of a ring for a very prominent man in town. The guy's daughter had commissioned the ring to reflect her father's activities in the Masons, the Shriners, the Rotary, Lions Club, and other social organizations. I never saw the finished project, but it must have brought a smile to the old guy's face when he got it. The mold looked a bit busy, but well-organized. Val's work was top-notch.

Wow, that is very cool. You just don't meet people like that very often. I imagine for him, similar to me, its not about having the buggy, its about building it. There is something very satisfying about building something with you own hands, and the challenges it poses that makes it fun. Especially when it is something some people say can't or shouldn't be done. For me its also about learning new things. Short of the hydraulics on my plow truck, and a couple repairs on a bobcat, I don't know that much about hydraulics, so something challenging like this is a reward in itself. There are many things on my list to build, and each time I do one, I gain more knowledge and experience. My son is 6, and he is now starting to take interest in these projects, and I hope it evolves into a father/son activity that can last a lifetime and make memories. I remember one of my best friends in school did things like this with his father, and I remember thinking that I wish I had something like that with my Dad.
 
  • #35
Did a little more work on the schematic. Added a flow divider and high-speed circuit.
 

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<h2>1. How do I calculate the weight distribution for my hydraulic dune buggy?</h2><p>To calculate the weight distribution for your hydraulic dune buggy, you will need to determine the total weight of the buggy, including the driver and any additional passengers. Then, you will need to measure the distance from the front axle to the center of gravity and the distance from the rear axle to the center of gravity. The weight distribution can be calculated by dividing the weight on the front axle by the total weight and multiplying by 100 to get a percentage.</p><h2>2. How do I determine the proper size and pressure for my hydraulic system?</h2><p>The size and pressure of your hydraulic system will depend on the weight and size of your dune buggy, as well as the terrain you will be driving on. It is important to consult with a hydraulic engineer or mechanic to determine the appropriate size and pressure for your specific design. Factors such as the type of pump, cylinder size, and valve size will also affect the performance of your hydraulic system.</p><h2>3. What is the ideal suspension setup for a hydraulic dune buggy?</h2><p>The ideal suspension setup for a hydraulic dune buggy will depend on the intended use of the buggy. For off-roading and dune jumping, a suspension with longer travel and softer springs may be more suitable. However, for high-speed racing, a stiffer suspension with shorter travel may be more effective. It is important to consider the weight distribution, terrain, and intended use when determining the ideal suspension setup for your dune buggy.</p><h2>4. How do I ensure the structural integrity of my hydraulic dune buggy?</h2><p>The structural integrity of your hydraulic dune buggy is crucial for safety and performance. To ensure this, it is important to use high-quality materials and follow proper welding techniques. It is also recommended to consult with a professional engineer to review your design and make any necessary adjustments. Regular maintenance and inspections are also important to identify and address any potential structural issues.</p><h2>5. What are the common challenges in designing a hydraulic dune buggy?</h2><p>Designing a hydraulic dune buggy can be a complex and challenging process. Some common challenges include finding the right balance between weight and strength, ensuring proper weight distribution, and selecting the appropriate components for the hydraulic system. It is important to thoroughly research and plan your design, as well as seek guidance from experienced professionals to overcome these challenges.</p>

1. How do I calculate the weight distribution for my hydraulic dune buggy?

To calculate the weight distribution for your hydraulic dune buggy, you will need to determine the total weight of the buggy, including the driver and any additional passengers. Then, you will need to measure the distance from the front axle to the center of gravity and the distance from the rear axle to the center of gravity. The weight distribution can be calculated by dividing the weight on the front axle by the total weight and multiplying by 100 to get a percentage.

2. How do I determine the proper size and pressure for my hydraulic system?

The size and pressure of your hydraulic system will depend on the weight and size of your dune buggy, as well as the terrain you will be driving on. It is important to consult with a hydraulic engineer or mechanic to determine the appropriate size and pressure for your specific design. Factors such as the type of pump, cylinder size, and valve size will also affect the performance of your hydraulic system.

3. What is the ideal suspension setup for a hydraulic dune buggy?

The ideal suspension setup for a hydraulic dune buggy will depend on the intended use of the buggy. For off-roading and dune jumping, a suspension with longer travel and softer springs may be more suitable. However, for high-speed racing, a stiffer suspension with shorter travel may be more effective. It is important to consider the weight distribution, terrain, and intended use when determining the ideal suspension setup for your dune buggy.

4. How do I ensure the structural integrity of my hydraulic dune buggy?

The structural integrity of your hydraulic dune buggy is crucial for safety and performance. To ensure this, it is important to use high-quality materials and follow proper welding techniques. It is also recommended to consult with a professional engineer to review your design and make any necessary adjustments. Regular maintenance and inspections are also important to identify and address any potential structural issues.

5. What are the common challenges in designing a hydraulic dune buggy?

Designing a hydraulic dune buggy can be a complex and challenging process. Some common challenges include finding the right balance between weight and strength, ensuring proper weight distribution, and selecting the appropriate components for the hydraulic system. It is important to thoroughly research and plan your design, as well as seek guidance from experienced professionals to overcome these challenges.

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