I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2? - Page 3





Page 3 of 6 FirstFirst 1 2 3 4 5 6 LastLast
Results 41 to 60 of 104
  1. #41
    Join Date
    Nov 2007
    Location
    Kathu
    Age
    58
    Posts
    8,569
    Thanked: 2231

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    I also think it is doable. Biltong have the experience in designing logic controllers. In the end there are numerous instruments that can read and monitor height. The new high Tech stuff are really small and robust. Just completed a project where Laser instruments were used to measure distance accurate to 1mm. Instrument smaller than a matchbox.

    As said in post above everyone building cars and Hot Rods these days put air suspension in them. Lots of aftermarket kits to chose from.
    I am sure that any design Engineer like Biltong will not have any trouble designing his own system.

    Simple little PLC straight from the shelve will be able to do it.
    Last edited by grips; 2019/08/18 at 04:00 PM.
    It is not what you buy its what you build.

  2. The Following User Says Thank You to grips For This Useful Post:


  3. #42
    Join Date
    Nov 2010
    Location
    Swakopmund
    Age
    50
    Posts
    2,982
    Thanked: 609

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by biltong View Post
    The stiffness of the airbag is determined by the air pressure.

    Since your coil springs at the front/rear has the same stiffness, it should be no problem to have each end on a common line.

    I think the reasoning behind doing each corner independently, may be to ensure that a line failure can only affect one corner.

    I do not think it i such a big deal if one does a good installation with quality pipe.


    If i then do a controller, then all it will be is something with a selected height for road use - which can be low. For off road use, one can have a standard and extended height.

    The system will be inherently self leveling.
    I'm with you on this. I think the 4 corner control of the Discovery is necessary in order to overcome the shortcomings generally associated with independent suspension and articulation. Since you would be working with solid axles, that might not be required.

    Just do keep in mind, that some older vehicles do have different spring strength left vs right, depending on weight distribution on the vehicle. E.g. my 60 series Cruiser does have dedicated left & right rear springs.
    2012 FJ Cruiser
    1983 FJ60 Landcruiser

  4. The Following User Says Thank You to HugoNotte For This Useful Post:


  5. #43
    Join Date
    May 2009
    Location
    Hillcrest, Malaysia
    Age
    63
    Posts
    18,511
    Thanked: 5885

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by Francois Theron View Post
    Fluffy and Sierra, why are you guys willfully derailing this discussion? I think it can be quite interesting to everyone but yet again testosterone is getting the better of everyone. Biltong is clearly building up to something starting from first principles, or so I think. Why pre empt things. If he is wrong then all will be revealed in the end (I hope).

    Can we let this carry on in an adult way without it turning into a pissing contest? Please!
    Because we/I am or rather was hoping to contribute with relevant experience on the subject. Very relevant with first hand experience in implementing and setting up EAS systems. I was hoping to contribute real and relevant experience and help with some pointers to save somebody some school fees.

    I merely pointed out that the original assumption that it is a simple problem that can be solved with a simplistic view and solution just wont work. Once you have experienced actually doing this, on a live vehicle you come to realise how deceptively complicated and difficult it is to get even half right.

    Instead of accepting some knowledgeable assistance and engaging in mature technical discussions one party resorted to personal insults and attacks and all sorts of irrelevant technical hyperbola.

    -------------

    If you are starting from first principle you have a few ways to get to an end result. Burn your fingers and pay school fees, or listen to, absorb and consider experienced advice. I have three Air Suspension Vehicles, a few diagnostic computers, a store room full of steel and air suspension components (which I would have been happy to donate to a co-operative engaging person that actually needs them) , designed and implemented air suspension control electronics mods, even published some on this forum.

    I am prepared to help anybody. Hell you cant afford an air suspension computer. No problem I can give you a circuit diagram, cable details and E-Mail you software to make your own. Then you can reset the EAS, set ride heights and monitor everything.. (Which I have also previously published on this forum)

    ------------

    Instead of embracing help and entering into meaningful and constructive debate, I am insulted and ridiculed.

    ------------

    I have no desire to enter into a fight.
    Last edited by Fluffy; 2019/08/18 at 04:39 PM.
    Cheers

    ZS5KAD
    3 V8's
    NA TwinTurbo SuperCharger
    A V6 and an inline 4

    The frogs are starting to notice that the water is getting warm but it is already too hot to do anything about it.....

  6. The Following 2 Users Say Thank You to Fluffy For This Useful Post:


  7. #44
    Join Date
    Sep 2006
    Location
    Robertson/ Larissa, Greece
    Age
    55
    Posts
    4,876
    Thanked: 2505

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by Fluffy View Post
    Because we/I am or rather was hoping to contribute with relevant experience on the subject. Very relevant with first hand experience in implementing and setting up EAS systems. I was hoping to contribute real and relevant experience and help with some pointers to save somebody some school fees.

    I merely pointed out that the original assumption that it is a simple problem that can be solved with a simplistic view and solution just wont work. Once you have experienced actually doing this, on a live vehicle you come to realise how deceptively complicated and difficult it is to get even half right.

    Instead of accepting some knowledgeable assistance and engaging in mature technical discussions one party resorted to personal insults and attacks and all sorts of irrelevant technical hyperbola.

    -------------

    If you are starting from first principle you have a few ways to get to an end result. Burn your fingers and pay school fees, or listen to, absorb and consider experienced advice. I have three Air Suspension Vehicles, a few diagnostic computers, a store room full of steel and air suspension components (which I would have been happy to donate to a co-operative engaging person that actually needs them) , designed and implemented air suspension control electronics mods, even published some on this forum.

    I am prepared to help anybody. Hell you cant afford an air suspension computer. No problem I can give you a circuit diagram, cable details and E-Mail you software to make your own. Then you can reset the EAS, set ride heights and monitor everything.. (Which I have also previously published on this forum)

    ------------

    Instead of embracing help and entering into meaningful and constructive debate, I am insulted and ridiculed.

    ------------

    I have no desire to enter into a fight.
    If biltong or anybody else wants to run the risk of burning their fingers or reinvent the wheel, surely it's their prerogative.

    Yet you seem determined to show that you are the expert and can't learn anything in the process. Is it so difficult to understand? I for one am curios to see what biltong is getting at. Do you think it is impossible that he might just have a novel idea?
    We can't change the wind but we can set our sails

  8. The Following User Says Thank You to Francois Theron For This Useful Post:


  9. #45
    Join Date
    Sep 2006
    Location
    Bloemfontein
    Age
    42
    Posts
    3,096
    Thanked: 1238

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by grips View Post
    I also think it is doable. Biltong have the experience in designing logic controllers. In the end there are numerous instruments that can read and monitor height. The new high Tech stuff are really small and robust. Just completed a project where Laser instruments were used to measure distance accurate to 1mm. Instrument smaller than a matchbox.
    And design experience in pneunatics, pneumatic control systems, medical gas and gaseous fire extinguishing systems.

    As a result, I have many angels to look from at this problem. Air suspension is not a unique silo of principles found nowhere else.

    The issues mentioned on this thread, are real and valid. But as said, it has been solved decades ago.

    I did not think about a purely electronic solution, but to do a bit of a hybrid. It can have some distinct advantages.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  10. The Following User Says Thank You to biltong For This Useful Post:


  11. #46
    Join Date
    Sep 2006
    Location
    Robertson/ Larissa, Greece
    Age
    55
    Posts
    4,876
    Thanked: 2505

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by biltong View Post
    And design experience in pneunatics, pneumatic control systems, medical gas and gaseous fire extinguishing systems.

    As a result, I have many angels to look from at this problem. Air suspension is not a unique silo of principles found nowhere else.

    The issues mentioned on this thread, are real and valid. But as said, it has been solved decades ago.

    I did not think about a purely electronic solution, but to do a bit of a hybrid. It can have some distinct advantages.
    Koos please carry on and share your ideas. I am very keen to see what you have in mind.
    We can't change the wind but we can set our sails

  12. The Following 4 Users Say Thank You to Francois Theron For This Useful Post:


  13. #47
    Join Date
    May 2009
    Location
    Hillcrest, Malaysia
    Age
    63
    Posts
    18,511
    Thanked: 5885

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by Francois Theron View Post
    If biltong or anybody else wants to run the risk of burning their fingers or reinvent the wheel, surely it's their prerogative.

    Yet you seem determined to show that you are the expert and can't learn anything in the process. Is it so difficult to understand? I for one am curios to see what biltong is getting at. Do you think it is impossible that he might just have a novel idea?
    A couple of concepts there.

    I can learn, and I can understand, and I am willing. Promise.

    Impossible idea, NO, improbable YES.

    Novel, I welcome that. But I seriously doubt it. The fundamental assumptions are, well --never mind.
    Cheers

    ZS5KAD
    3 V8's
    NA TwinTurbo SuperCharger
    A V6 and an inline 4

    The frogs are starting to notice that the water is getting warm but it is already too hot to do anything about it.....

  14. The Following User Says Thank You to Fluffy For This Useful Post:


  15. #48
    Join Date
    Sep 2006
    Location
    Bloemfontein
    Age
    42
    Posts
    3,096
    Thanked: 1238

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by sierrafery View Post
    for example on the rear if you have only one air supply line and a valve for each spring it means that there can be many cases when both bags must be inflated at the same time like when you put a load in the boot and a heavy guy will hop in on the let's say right side, then the controller should start the compressor and open both valves at the same time to inflate both bags as to relevel the vehicle, as both bags are connected to the same line when both valves are open the bags are connected to each other so the pressure in the system works like in communicating vessels which means the right side where the heavy guy is will go down while the left will go up and then the controller will insist to relevel untill the whole thing blows, the same theory is valid for front too, with your kind of setup with a common air supply line for two bags once both valves are opened at the same time that vehicle will be at the same level all around only if the weight is evenly placed in it as to have the same pressure on each corner ... that's why each bag needs it's own air supply line if you see what i mean.... i hope i'm wrong and you'll be able to make it like you think but i doubt that if it was so simple LR would have overcomplicated it with separate lines for each bag just like that
    Sierrafery,

    I figured what ticked me off about your post...

    If anyone writes a never ending sentence like this with this sloppy punctuation, I find it really hard to take him serious.

    If you are willing to rewrite this into something proper, accept my apology.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  16. #49
    Join Date
    Sep 2006
    Location
    Bloemfontein
    Age
    42
    Posts
    3,096
    Thanked: 1238

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Thanks Francois. I will continue a bit then.


    As pointed out, many mechanical systems are such that what happens on one end, effects the entire system.

    (I find designing controller is this regard easy, as inputs and outputs are physically completely independent. All the combining is via software.)


    Now first of all, lets just compare a steel spring with an air spring, and we make the following assumptions:

    1. Both the air spring and the steel spring has the exact same travel on the vehicle.

    2. Both works from the same initial height.


    With an air spring, we can use the ideal gas law of P1 x V1 / T1= P2 x V2 / T2 if the filled volume does not change.

    For an air spring to start lifting the corner vehicle, a pressure of P1 is required. The actual height that you want to lift it to, is determined by V1.

    For initial states, temperature can be ignored, but once the work is done and it heats up, temperature will start influence the ride height and will eventually settle where the heat rejection equals the heat generation.

    Because of the above, the spring force of an air spring is non-linear, compared to a steel spring that is exactly linear.

    This is then where the air springs gains comfort. At the "middle" position, the air spring will have more movement for a smaller change in spring force, compared to a steel spring that is more direct - hence the cushioned effect experienced by the occupants of the vehicle with air springs.

    Based on the pure P1 x V1 / T1= P2 x V2 / T2 relationship, an air spring should have a complete parabolic response, but since that travel is limited, it stars working against itself and will at fully extended height also have a zero force that it can apply to a corner.

    The graph that I attach, is purely conceptual and not based on an actual product. The behavior though looks similar. In this graph, I took the travel value of 1 as the middle position with 1.5 as fully extended and 0.5 as fully compressed.


    Right, if two air bladders are on the same line and the fact that spring force is mostly determined by pressure only, it will happen that the vehicle will sag abnormally to one side compared to a steel spring, if the one side is heavier and the air can migrate between the two bladders with no restriction in between.


    The reason then for my tanks examples was to demonstrate how portions of the above problem is dealt with.

    In Scenario 1, with all the tanks on the same level, we only have about 2 or 3 meters of water height in each tank that can exert force on the pipe manifold to the pump.

    What happens then is because that pressure is very similar in comparison to the pressure loss in the pipes on the way to the pump, the tank closest to the pump will run empty first and the last one will be almost full of water. The tanks would not equilise levels as expected. The way to counter this, will be by connecting tank 1 and 2, then tank 3 and 4 and then the 1/2 3/4 manifolds. That way you stagger the pressure drops to be all the same and the tanks will equilise.

    In scenario 2 however, with the tanks under high pressure, this is not a problem since the static pressure is now of magnitudes higher than the possible pressure losses in the pipes. The tanks will deliver about equal amounts of water. I have used this principle in


    The above principle then applies when one wants to fill and empty two air bladders from a common line. When one Tees off, you need to put in an restriction to both sides that offers a more resistance than the pipes and fittings to the bladders. To ensure that the air does not migrate, you only need a one-way valve in each line.

    The same goes for deflating. A restriction in the line that is greater than the pipe losses and fittings, should be inserted to allow for even deflation.

    To have have two bladders on the same axle fed from the same height control valve, is possible and commonly done, but not without some inline components.

    A further implication of the above, is that one does this at the expense of a higher line pressure, which makes a reservoir in the system compulsory.


    An air suspension system is not quite the kind of system that you can use to do active suspension control. It simply has too much cushion to achieve that and is not fast enough - especially when the compressor starts to deteriorate.

    It is not problem to fill the system while the vehicle is stationary and level, and keep it there for as long as the vehicle is moving.

    As long as there are no leaks in the system, and as long as the air volume in each bladder is not changed, it will behave predictably, and independently.


    As you know, air suspensions on vehicles can be quite high maintenance.


    The question here is if the less complexity and perhaps increased reliability of a 2-channel system can be justified compared to the much increased flexibility a 4-channel system offers.
    Attached Images Attached Images  
    Last edited by biltong; 2019/08/18 at 07:26 PM.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  17. The Following User Says Thank You to biltong For This Useful Post:


  18. #50
    Join Date
    Sep 2006
    Location
    Bloemfontein
    Age
    42
    Posts
    3,096
    Thanked: 1238

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by Fluffy View Post
    I can learn, and I can understand, and I am willing. Promise.

    Impossible idea, NO, improbable YES.

    Cool. Will that be for all subjects?
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  19. #51
    Join Date
    Sep 2006
    Location
    Bloemfontein
    Age
    42
    Posts
    3,096
    Thanked: 1238

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by grips View Post
    Simple little PLC straight from the shelve will be able to do it.
    That would depend a on the programming functions it offers.

    This is the kind of thing that needs straight coding.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  20. The Following User Says Thank You to biltong For This Useful Post:


  21. #52
    Join Date
    May 2009
    Location
    Hillcrest, Malaysia
    Age
    63
    Posts
    18,511
    Thanked: 5885

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by biltong View Post
    Cool. Will that be for all subjects?
    Yes, obviously, how on earth do you think I got to know everything.

    By learning. DUH.
    Last edited by Fluffy; 2019/08/18 at 09:25 PM.
    Cheers

    ZS5KAD
    3 V8's
    NA TwinTurbo SuperCharger
    A V6 and an inline 4

    The frogs are starting to notice that the water is getting warm but it is already too hot to do anything about it.....

  22. #53
    Join Date
    May 2009
    Location
    Hillcrest, Malaysia
    Age
    63
    Posts
    18,511
    Thanked: 5885

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by biltong View Post
    That would depend a on the programming functions it offers.

    This is the kind of thing that needs straight coding.
    The programming and coding ease, or mechanism or efficiency or processing power is not the issue. ( look what they had to put a man on the moon ).

    Itís the algorithms and the mechanics it is applied to.
    Cheers

    ZS5KAD
    3 V8's
    NA TwinTurbo SuperCharger
    A V6 and an inline 4

    The frogs are starting to notice that the water is getting warm but it is already too hot to do anything about it.....

  23. #54
    Join Date
    May 2009
    Location
    Hillcrest, Malaysia
    Age
    63
    Posts
    18,511
    Thanked: 5885

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by biltong View Post
    Thanks Francois. I will continue a bit then.


    As pointed out, many mechanical systems are such that what happens on one end, effects the entire system.

    (I find designing controller is this regard easy, as inputs and outputs are physically completely independent. All the combining is via software.)


    Now first of all, lets just compare a steel spring with an air spring, and we make the following assumptions:

    1. Both the air spring and the steel spring has the exact same travel on the vehicle.

    2. Both works from the same initial height.


    With an air spring, we can use the ideal gas law of P1 x V1 / T1= P2 x V2 / T2 if the filled volume does not change.

    For an air spring to start lifting the corner vehicle, a pressure of P1 is required. The actual height that you want to lift it to, is determined by V1.

    For initial states, temperature can be ignored, but once the work is done and it heats up, temperature will start influence the ride height and will eventually settle where the heat rejection equals the heat generation.

    Because of the above, the spring force of an air spring is non-linear, compared to a steel spring that is exactly linear.

    This is then where the air springs gains comfort. At the "middle" position, the air spring will have more movement for a smaller change in spring force, compared to a steel spring that is more direct - hence the cushioned effect experienced by the occupants of the vehicle with air springs.

    Based on the pure P1 x V1 / T1= P2 x V2 / T2 relationship, an air spring should have a complete parabolic response, but since that travel is limited, it stars working against itself and will at fully extended height also have a zero force that it can apply to a corner.

    The graph that I attach, is purely conceptual and not based on an actual product. The behavior though looks similar. In this graph, I took the travel value of 1 as the middle position with 1.5 as fully extended and 0.5 as fully compressed.


    Right, if two air bladders are on the same line and the fact that spring force is mostly determined by pressure only, it will happen that the vehicle will sag abnormally to one side compared to a steel spring, if the one side is heavier and the air can migrate between the two bladders with no restriction in between.


    The reason then for my tanks examples was to demonstrate how portions of the above problem is dealt with.

    In Scenario 1, with all the tanks on the same level, we only have about 2 or 3 meters of water height in each tank that can exert force on the pipe manifold to the pump.

    What happens then is because that pressure is very similar in comparison to the pressure loss in the pipes on the way to the pump, the tank closest to the pump will run empty first and the last one will be almost full of water. The tanks would not equilise levels as expected. The way to counter this, will be by connecting tank 1 and 2, then tank 3 and 4 and then the 1/2 3/4 manifolds. That way you stagger the pressure drops to be all the same and the tanks will equilise.

    In scenario 2 however, with the tanks under high pressure, this is not a problem since the static pressure is now of magnitudes higher than the possible pressure losses in the pipes. The tanks will deliver about equal amounts of water. I have used this principle in


    The above principle then applies when one wants to fill and empty two air bladders from a common line. When one Tees off, you need to put in an restriction to both sides that offers a more resistance than the pipes and fittings to the bladders. To ensure that the air does not migrate, you only need a one-way valve in each line.

    The same goes for deflating. A restriction in the line that is greater than the pipe losses and fittings, should be inserted to allow for even deflation.

    To have have two bladders on the same axle fed from the same height control valve, is possible and commonly done, but not without some inline components.

    A further implication of the above, is that one does this at the expense of a higher line pressure, which makes a reservoir in the system compulsory.


    An air suspension system is not quite the kind of system that you can use to do active suspension control. It simply has too much cushion to achieve that and is not fast enough - especially when the compressor starts to deteriorate.

    It is not problem to fill the system while the vehicle is stationary and level, and keep it there for as long as the vehicle is moving.

    As long as there are no leaks in the system, and as long as the air volume in each bladder is not changed, it will behave predictably, and independently.


    As you know, air suspensions on vehicles can be quite high maintenance.


    The question here is if the less complexity and perhaps increased reliability of a 2-channel system can be justified compared to the much increased flexibility a 4-channel system offers.
    With respect. That is one helluva long and complex post that must have taken some time and effort, but it (appears) is based on theory and assumptions that just don’t apply to a 4x4 vehicle.

    One of the most interesting statements is about two bladders on one height control valve needing extra inline components. Hell, why not just use two control valves, chuck out the extra components and get independent control and get it done properly, simpler, and cheaper. You have all these complex devices to ensure even inflation and deflation. Rather just replace this complex design with two control valves. All your problems are solved, including the dynamic problems.
    Last edited by Fluffy; 2019/08/18 at 10:03 PM.
    Cheers

    ZS5KAD
    3 V8's
    NA TwinTurbo SuperCharger
    A V6 and an inline 4

    The frogs are starting to notice that the water is getting warm but it is already too hot to do anything about it.....

  24. #55
    Join Date
    Oct 2015
    Location
    Romania/Hungary
    Age
    52
    Posts
    552
    Thanked: 113

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Thankw for taking the time to respond, i've read your long post twice and i still can't get the gist of the following theory:
    The above principle then applies when one wants to fill and empty two air bladders from a common line. When one Tees off, you need to put in an restriction to both sides that offers a more resistance than the pipes and fittings to the bladders. To ensure that the air does not migrate, you only need a one-way valve in each line.
    The same goes for deflating. A restriction in the line that is greater than the pipe losses and fittings, should be inserted to allow for even deflation.
    Do you mean restrictoprs and one way valves for inflation and for deflation on the same line which goes into a bladder? cos then the one for deflation won't let the air through to inflate and the valve for inflation will stop the deflation

    anyway, seing that long post just shows that it's like i said at the begining of this thread ... not so simple
    2000 Discovery Td5 ES manual, tuned

    Hawkeye v.6, Nanocom EVO,
    VDM UCANDAS, oscilloscope


    i DON'T ANSWER TO TECHNICAL QUESTIONS IN PM'S

    ALL MY ADVICES ARE BASED ON MY OWN EXPERIENCE AND MY WAY OF UNDERSTANDING THE DESCRIPTION AND OPERATION OF SYSTEMS... I'M NOT A LAND ROVER SPECIALIST JUST AN ADDICTED ENTHUSIAST

  25. #56
    Join Date
    Sep 2006
    Location
    Bloemfontein
    Age
    42
    Posts
    3,096
    Thanked: 1238

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by Fluffy View Post
    With respect. That is one helluva long and complex post that must have taken some time and effort, but it (appears) is based on theory and assumptions that just donít apply to a 4x4 vehicle.
    Everything in there applies and the assumption are valid.

    I have deliberately chosen a comparison of air vs steel which can be significantly altered based on the choice of springs.

    If you know as much as you say you do, the above would be an important part of the concept evaluation and you would have offered alternatives.


    Quote Originally Posted by Fluffy View Post
    You have all these complex devices to ensure even inflation and deflation. Rather just replace this complex design with two control valves. All your problems are solved, including the dynamic problems.
    None of the line devices are complex from a mechanical point of view and it is not as if there are thousands of it like you make it sound.

    I guess if you find an orifice to be complex, at least you are right in that it is a bit of trick to get sizing right. But other than that, I find it hard to see the complexity in it.

    Using the correct tone of voice, R 10 can be made to sound like a lot of money - and that is basically what you are doing here.



    I know very well what can be done with a 4-channel system, what components are needed and what flexibility it offers.

    I also know that programming it will take more effort.


    If you cannot see the possible advantages of any other way, then it really is not my problem.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  26. #57
    Join Date
    Sep 2006
    Location
    Bloemfontein
    Age
    42
    Posts
    3,096
    Thanked: 1238

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Quote Originally Posted by Fluffy View Post
    The programming and coding ease, or mechanism or efficiency or processing power is not the issue. ( look what they had to put a man on the moon ).

    Itís the algorithms and the mechanics it is applied to.

    Yes, and what makes this aspect unique to this scenario?
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  27. #58
    Join Date
    Nov 2007
    Location
    Kathu
    Age
    58
    Posts
    8,569
    Thanked: 2231

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    I think it is even possible to build a mechanical system only with good knowledge of pneumatic controllers only.
    Biltong can pull this off with ease. I am going to follow this thread with interest.
    Think we should all sit back and see how Biltong build his system.
    Last edited by grips; 2019/08/19 at 07:01 AM.
    It is not what you buy its what you build.

  28. The Following 2 Users Say Thank You to grips For This Useful Post:


  29. #59
    Join Date
    Sep 2006
    Location
    Bloemfontein
    Age
    42
    Posts
    3,096
    Thanked: 1238

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Just for reference an extraction from the RAVE manual on the P38 EAS.

    Regarding the comment by Fluffy, I find it quite amusing that they also see the need to use "complex" devices like non return valves in there to ensure a wanted flow direction.


    There is no mention in the description of the working of the system, that it is able to compensate for side slopes - and that would have been listed as one of the main features if it was the intend.

    This is nothing more than a height control system with some integration with other vehicle systems to reduce driver input.
    Attached Images Attached Images
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  30. The Following User Says Thank You to biltong For This Useful Post:


  31. #60
    Join Date
    Nov 2007
    Location
    Kathu
    Age
    58
    Posts
    8,569
    Thanked: 2231

    Default Re: I can't sleep so I thought: What about fitting RR P38 Air suspension in a D2?

    Very basic pneumatics in the attached PDF document. One can build that circuit walking in your sleep.
    It is not what you buy its what you build.

Page 3 of 6 FirstFirst 1 2 3 4 5 6 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •