Flexi Chassis an Appreciation

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proto87stores

Re: Flexi Chassis an Appreciation

Postby proto87stores » Wed Apr 05, 2017 2:28 am

Crepello wrote:
Alan Turner wrote:But sprung suspension systems cannot produce equal weigh distribution in the dynamic phase - only when the system is static can that be so.


Neither do rigid beams! When a beam rotates to a new equilibrium point, it must necessarily be due to unequal moments at its ends.


No. If has has unequal loads and is free to rotate, it will continue to rotate and accelerate its rotation.

The cases we are looking are where the ends of rigid equalizing beams are constrained by the height of the rail under each wheel at each end of the pivoted beam. The central fulcrum will be moved until it sits at the average height of it's ends. Unless the rails are springy, the movement is almost instantaneous in following the profile of the rail height.

proto87stores

Re: Flexi Chassis an Appreciation

Postby proto87stores » Wed Apr 05, 2017 2:32 am

Alan Turner wrote:
proto87stores wrote:
I still claim that only the physics of equalization maintains constant wheel weighting over the various track imperfections and dynamic impulses. And AFAIK, only (vertical plane fixed) pivoting beams can avoid the need for vertical sliding bearings. Both advantages of the Flexi-chas design taken to its logical modern possibilities.

Andy


But sprung suspension systems cannot produce equal weigh distribution in the dynamic phase - only when the system is static can that be so.

When a spring compresses the load in that spring rises, so any bump in the track that causes a spring to compress will cause weight to be transferred to that spring and therefore causes load to be shed from other springs in the system.

regards

Alan


If the track is twisted, then the sprung suspension systems don't produce equal weights, even when static.

Andy

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Re: Flexi Chassis an Appreciation

Postby Crepello » Wed Apr 05, 2017 8:30 pm

proto87stores wrote:
Crepello wrote:
Alan Turner wrote:But sprung suspension systems cannot produce equal weigh distribution in the dynamic phase - only when the system is static can that be so.


Neither do rigid beams! When a beam rotates to a new equilibrium point, it must necessarily be due to unequal moments at its ends.


No. If has has unequal loads and is free to rotate, it will continue to rotate and accelerate its rotation.

The cases we are looking are where the ends of rigid equalizing beams are constrained by the height of the rail under each wheel at each end of the pivoted beam. The central fulcrum will be moved until it sits at the average height of it's ends. Unless the rails are springy, the movement is almost instantaneous in following the profile of the rail height.

I was pointing out that the behaviour of the rigid beam system has an analogue of Alan's criticism of the dynamic behaviour of sprung suspension.

proto87

Re: Flexi Chassis an Appreciation

Postby proto87 » Wed Apr 05, 2017 11:58 pm

Crepello wrote:
proto87stores wrote:
Crepello wrote:
Alan Turner wrote:But sprung suspension systems cannot produce equal weigh distribution in the dynamic phase - only when the system is static can that be so.


Neither do rigid beams! When a beam rotates to a new equilibrium point, it must necessarily be due to unequal moments at its ends.


No. If has has unequal loads and is free to rotate, it will continue to rotate and accelerate its rotation.

The cases we are looking are where the ends of rigid equalizing beams are constrained by the height of the rail under each wheel at each end of the pivoted beam. The central fulcrum will be moved until it sits at the average height of it's ends. Unless the rails are springy, the movement is almost instantaneous in following the profile of the rail height.

I was pointing out that the behaviour of the rigid beam system has an analogue of Alan's criticism of the dynamic behaviour of sprung suspension.


I can't see that as an analogue. When one section of rail is a bump under one moving wheel, the resistance of the chassis (plus body if unsprung) to movement is only it's inertia against the rapid change. The weight on the wheel at either end of the equalizing beam doesn't change, whether it's tilted or not.

That's the fundamental difference between equalization and springing hitting a bump. A sprung wheel sees proportionally increasing resistance as the wheel tries to rise, while an equalized wheel sees no difference in resistance as the wheel rises. Basically it is free to follow the rail height profile without incurring extra loading. Hence the track holding excellence.

Andy

billbedford

Re: Flexi Chassis an Appreciation

Postby billbedford » Fri Apr 07, 2017 7:39 pm

proto87 wrote:That's the fundamental difference between equalization and springing hitting a bump. A sprung wheel sees proportionally increasing resistance as the wheel tries to rise, while an equalized wheel sees no difference in resistance as the wheel rises. Basically it is free to follow the rail height profile without incurring extra loading. Hence the track holding excellence.


You have that backwards. An equalised wheel has to lift the whole of the weight it supports as soon as it hits a bump, while as sprung wheel only has to deflect the spring and the energy stored in the spring deflection will lift the supported weight at a later time.

You still haven't listed all the real-life situations, i.e. non-models, where unsprung equalisation is preferred over the use of springs.

proto87stores

Re: Flexi Chassis an Appreciation

Postby proto87stores » Fri Apr 07, 2017 10:02 pm

billbedford wrote:
proto87 wrote:That's the fundamental difference between equalization and springing hitting a bump. A sprung wheel sees proportionally increasing resistance as the wheel tries to rise, while an equalized wheel sees no difference in resistance as the wheel rises. Basically it is free to follow the rail height profile without incurring extra loading. Hence the track holding excellence.


You have that backwards. An equalised wheel has to lift the whole of the weight it supports as soon as it hits a bump, while as sprung wheel only has to deflect the spring and the energy stored in the spring deflection will lift the supported weight at a later time.

You still haven't listed all the real-life situations, i.e. non-models, where unsprung equalization is preferred over the use of springs.


Sorry Bill, That's incorrect.

The static load on your single wheel spring is the weight it supports, which has already compressed it to around the 50% position. If your bump tries to dynamically lift the wheel, but instead compresses the spring further, then the force to compress the spring further is the static weight it already supports, PLUS the extra force needed to compress the spring. That's Hooke's Law. I think that's where your past misunderstandings of springing vs. equalization are coming from.

I've already stated this earlier, but yes the equalized wheel has to lift its beam and fulcrum instantly, but by only half as far, which has to lift the corner of an unsprung body (worst case) then by only a quarter as far. But that's pretty close to one sprung wheel having to start to lift it's closest body corner by the full bump height.

In my case I let the equalized (but very light) wheel and beam(s) raise the fulcrum(s), then only (if worthwhile) add smoothing springing between the fulcrum(s) and the body, (four point suspension) so that the wheel movement over a bump has the least possible resistance and the simpler body springing does the later lifting, and with a desirable soft spring rate.

Andy

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Guy Rixon
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Re: Flexi Chassis an Appreciation

Postby Guy Rixon » Sat Apr 08, 2017 10:30 am

Seems to me that in both the sprung and compensated cases the centre of mass rises; in the compensated case it rises immediately and in the sprung case it rises more slowly; i.e. with lower acceleration. The springs in a full-size vehicle are there to reduce the acceleration felt by the load, which doesn't matter in a model. In either case, all the wheels have extra load so track holding is not compromised.

I think we need to consider what happens when there is a dip in the track under one wheel. The reactive force on that wheel is reduced - to zero if the dip is deep enough - and this could lead to flange climbing. Does a compensated suspension restore load on this wheel more quickly than a sprung suspension?

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grovenor-2685
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Re: Flexi Chassis an Appreciation

Postby grovenor-2685 » Sat Apr 08, 2017 6:25 pm

I've already stated this earlier, but yes the equalized wheel has to lift its beam and fulcrum instantly, but by only half as far, which has to lift the corner of an unsprung body (worst case) then by only a quarter as far. But that's pretty close to one sprung wheel having to start to lift it's closest body corner by the full bump height.

All of which only applies to the case of a vehicle with two 4 wheel bogies, which has been acknowledged on here as the simplest cse for simple unsprung equalisation. Most of the contributions from this side of the pond are related to 4 wheel and 6 wheel vehicles which are rather more difficult.
For track holding on roughish track at any sort of speed you need to take account of the impulse imparted by the irregularity and the response to this by the suspension, which is where the benefits of springs show up.
Regards
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Keith
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jon price
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Re: Flexi Chassis an Appreciation

Postby jon price » Sat Apr 08, 2017 6:56 pm

Speaking as an L&NWR man at heart I must say that anyone hitting irregular track at speed deserves everything they get, and the subsequent inquiry. At Scalefour North I saw a beautiful layout with lovely engines, one of which kept falling off the track (I wont embarass them by naming names). Was it the suspension (badly balanced CSB? iregular compensation?) No it was the (scale )18" gap in the rails between the fiddle yard and the layout. It seems to me if you want to run express services you need high class track laying. If you are shunting a yard you can (as many minor railways did) get away with murder, but it has to be finescale murder as nowhere ran regular services over 18" gaps.

Or do you. This is all based on "that doesnt seem right to me" logic.

Here is a fim by experts at derailing trains (admittedly using a four-coupled loco and bogie stock).
https://www.youtube.com/watch?v=kdfFCaDOM3k.

Seems like our trains should be a bit more forgiving, so maybe scaling effects are the most significant issue here?
Connah's Quay Workshop threads: viewforum.php?f=125

proto87stores

Re: Flexi Chassis an Appreciation

Postby proto87stores » Sat Apr 08, 2017 7:35 pm

Guy Rixon wrote:Seems to me that in both the sprung and compensated cases the centre of mass rises; in the compensated case it rises immediately and in the sprung case it rises more slowly; i.e. with lower acceleration. The springs in a full-size vehicle are there to reduce the acceleration felt by the load, which doesn't matter in a model. In either case, all the wheels have extra load so track holding is not compromised.

I think we need to consider what happens when there is a dip in the track under one wheel. The reactive force on that wheel is reduced - to zero if the dip is deep enough - and this could lead to flange climbing. Does a compensated suspension restore load on this wheel more quickly than a sprung suspension?


Equalization is just a system of levers. What works in one direction, works in reverse in the same way.

The weight on a descending equalized wheel is still constant, all the way down, due to the leveraged weight of the body acting at the centre of gravity.

The point about speed is a little more interesting. Since the leverage of the descending c of g is now working backwards, the acceleration at which a relatively very light equalized wheel can drop is multiplied by the extent of the leverage. So its ability to follow the rail dip profile down is going to be at least 4 times faster than the c of g can drop. 4 x G presumably.

A sprung wheel can only accelerate downwards due its own gravity and the proportional reducing force of the static spring compression. That only starts at the balanced I x G force (gravity) from the static equilibrium position and yes, reduces all the way down to zero when the spring is fully extended. How fast the spring can accelerate the wheel down I think is the good old F=mA equation. Whatever that turns out to be depending on the spring and the mass of the wheel and hornblock and half the axle, reduced by the hornblock friction and any damping.

Andy

proto87stores

Re: Flexi Chassis an Appreciation

Postby proto87stores » Sat Apr 08, 2017 9:37 pm

grovenor-2685 wrote:
I've already stated this earlier, but yes the equalized wheel has to lift its beam and fulcrum instantly, but by only half as far, which has to lift the corner of an unsprung body (worst case) then by only a quarter as far. But that's pretty close to one sprung wheel having to start to lift it's closest body corner by the full bump height.

All of which only applies to the case of a vehicle with two 4 wheel bogies, which has been acknowledged on here as the simplest cse for simple unsprung equalisation. Most of the contributions from this side of the pond are related to 4 wheel and 6 wheel vehicles which are rather more difficult.
For track holding on roughish track at any sort of speed you need to take account of the impulse imparted by the irregularity and the response to this by the suspension, which is where the benefits of springs show up.
Regards


Image

Here's how we can do a 6 wheel chassis. 6 wheel full equalization, then four point springing of each fulcrum to the frame. Four point sprung mounting over equalization gives 100% of the possible benefits of both equalization and springing.

This obviously works as a bogie, but more to the points I've been making, also works completely stably standalone. I.e it could just as easily be a steam 0-6-0 chassis. Ditto configured for an 0-8-0. And in my personal case, my N7 0-6-2's. A practical and stable 0-4-0 example is already underway separately. That's what the 12 ton wagon kits are for. The design issues for those are pretty much ironed out already. But I'm going to build and video a lot of test and demo units regardless. Then enjoy them personally, but with P4 wheels on 16.5 gauge. :D

As to my quoting the simplest case of equalization first, that was deliberate. But I would like you to point out how equalization becomes less effective than wheel springing, if used on more complex chassis and wheel configurations. The building of the solid Physics comparison case, part by part, is on the previous pages. I really don't see how, if you couldn't find an objection to one or more of the earlier parts,including the various impulse handling answers, you can then suddenly challenge the logical conclusion.

Andy

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grovenor-2685
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Re: Flexi Chassis an Appreciation

Postby grovenor-2685 » Sun Apr 09, 2017 9:18 am

including the various impulse handling answers,

Could you point to these, I don't recollect impulses being mentioned till now?
you can then suddenly challenge the logical conclusion

what challenge? I was just pointing out that the two sides of this discussion are mostly looking at different cases.
Regards
Regards
Keith
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andrew jukes

Re: Flexi Chassis an Appreciation

Postby andrew jukes » Sun Apr 09, 2017 11:59 am

I think Andy's 3-axle, 4-beam, 4 fulcrums layout is interesting and I've played around with it myself. If one forgets all the dynamic stuff, then the issue with this layout with fixed fulcrums is that it obviously cannot cope with track twist. Compliance/springs at the fulcrums can be the answer and, without the need to run on staggered (US) rail joints and with good quality track, not much compliance is needed. The problem in applying the layout to an 0-6-0 loco is that there is limited pitch stability.

Regards Andrew

billbedford

Re: Flexi Chassis an Appreciation

Postby billbedford » Sun Apr 09, 2017 4:46 pm

proto87stores wrote:Equalization is just a system of levers. What works in one direction, works in reverse in the same way.

The weight on a descending equalized wheel is still constant, all the way down, due to the leveraged weight of the body acting at the centre of gravity.

The point about speed is a little more interesting. Since the leverage of the descending c of g is now working backwards, the acceleration at which a relatively very light equalized wheel can drop is multiplied by the extent of the leverage. So its ability to follow the rail dip profile down is going to be at least 4 times faster than the c of g can drop. 4 x G presumably.

A sprung wheel can only accelerate downwards due its own gravity and the proportional reducing force of the static spring compression. That only starts at the balanced I x G force (gravity) from the static equilibrium position and yes, reduces all the way down to zero when the spring is fully extended. How fast the spring can accelerate the wheel down I think is the good old F=mA equation. Whatever that turns out to be depending on the spring and the mass of the wheel and hornblock and half the axle, reduced by the hornblock friction and any damping.



Can we have some worked examples please?

You still haven't answered the question about why there are so few full-sized vehicles without springs.

proto87stores

Re: Flexi Chassis an Appreciation

Postby proto87stores » Sun Apr 09, 2017 7:07 pm

billbedford wrote:
proto87stores wrote:Equalization is just a system of levers. What works in one direction, works in reverse in the same way.

The weight on a descending equalized wheel is still constant, all the way down, due to the leveraged weight of the body acting at the centre of gravity.

The point about speed is a little more interesting. Since the leverage of the descending c of g is now working backwards, the acceleration at which a relatively very light equalized wheel can drop is multiplied by the extent of the leverage. So its ability to follow the rail dip profile down is going to be at least 4 times faster than the c of g can drop. 4 x G presumably.

A sprung wheel can only accelerate downwards due its own gravity and the proportional reducing force of the static spring compression. That only starts at the balanced I x G force (gravity) from the static equilibrium position and yes, reduces all the way down to zero when the spring is fully extended. How fast the spring can accelerate the wheel down I think is the good old F=mA equation. Whatever that turns out to be depending on the spring and the mass of the wheel and hornblock and half the axle, reduced by the hornblock friction and any damping.



Can we have some worked examples please?

"Statics and Dynamics", J.L. Meriam, Pub John Wiley Sons. Or similar text books, have everything you need.

You still haven't answered the question about why there are so few full-sized vehicles without springs.


I've neglected doing so, partly because Keith already mostly answered it earlier and partly as there is no way the answer will change, let alone affect, either the way you, or I, or the rest of the S4 Society, build working model suspension. So it's just another irrelevant distraction. However, I'll expand on Keith's answer and repeat that it's fundamentally the economics of Physics vs Scale, (cost of the strength and durability of materials in large sizes and weights), plus the added factor of carrying humans in comfort and/or delicate products without damage.

It''s not economic or as convenient to make long, strong, custom length, equalizing beams and their fulcrums for full size vehicles when springing wheels can be done much less expensively, and by using higher volume, lower weight, standard components. If you are considering human vehicles that also have "ground level entry" and/or "steering", then it becomes even more troublesome.

Andy

proto87stores

Re: Flexi Chassis an Appreciation

Postby proto87stores » Sun Apr 09, 2017 8:13 pm

grovenor-2685 wrote:
including the various impulse handling answers,

Could you point to these, I don't recollect impulses being mentioned till now?
you can then suddenly challenge the logical conclusion

what challenge? I was just pointing out that the two sides of this discussion are mostly looking at different cases.
Regards


I only used the word "impulse" rarely, instead mainly talking about comparing the dynamic situation of a "bump" cause a rising wheel and the lesser vs. delayed effect of lifting the body c of m in the equalized vs. sprung wheel case. I thought the layman "bump" was more generally understandable across the posting audience. And in the case of rolling wheels, our "impulses" are actually a mixture of shallow angle impact and a slower following rolling over lifting until the lowest point of the wheel is directly over the edge of the height change, which I don't particularly want to elaborate on. See (Feb 21 4.15 pm, Feb 21, 11.21pm, March 3 rd, 7.40 pm, Mar 27, 6:31 pm, Apr 01, 2:07 am, Apr 02, 11:49 pm, Apr 05, 2:10 am, Apr 05, 11:58 pm, Apr 07, 10:02 pm, Apr 08, 7:35 pm)

I thought I'd taken pains to indicate that equalizing beams and fulcrums could be stacked (and added transversely) as well as paralleled to handle the general case. Just as In the Flexichas book. E.g. Lots of "beam(s) and fulcrum(s). I've always been trying to imply, if perhaps not as clearly or as much, that I'm proposing a general solution that includes most steam locomotive configurations. So far I've not seen any reason to restrict that. (Feb 14 1.12 am, Feb 20, 7.14 pm)

Andy

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Re: Flexi Chassis an Appreciation

Postby grovenor-2685 » Sun Apr 09, 2017 10:11 pm

Ok search does reveal that you used 'impulse' in this message.but made it synonymous with a vague sort of bump.
I thought the layman "bump" was more generally understandable across the posting audience.

My apologies, I thought we were the audience.
I thought I'd taken pains to indicate that equalizing beams and fulcrums could be stacked (and added transversely) as well as paralleled to handle the general case.
I don't think there is any argument on that, the flexichas book, S4 digest and CLAG website do cover it all pretty thoroughly.
Regards
Regards
Keith
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proto87

Re: Flexi Chassis an Appreciation

Postby proto87 » Mon Apr 10, 2017 11:00 pm

andrew jukes wrote:I think Andy's 3-axle, 4-beam, 4 fulcrums layout is interesting and I've played around with it myself. If one forgets all the dynamic stuff, then the issue with this layout with fixed fulcrums is that it obviously cannot cope with track twist. Compliance/springs at the fulcrums can be the answer and, without the need to run on staggered (US) rail joints and with good quality track, not much compliance is needed. The problem in applying the layout to an 0-6-0 loco is that there is limited pitch stability.

Regards Andrew


The fully equalized only version of that would have additional transverse equalization on the end wheels and an overriding pair of longitudinal beams (one each side) loading the two side fulcrums shown, instead of the springs.

The 4 point body mounting would then instead be on the fulcrum centres of the additional upper side beams and the fulcrum centres of the two transverse beams. In that way the chassis also handles moderate twist, but still fully equalizes. Ditto for an 0-6-0 and an 0-8-0 configuration. Providing no beam is springy, there will be zero pitch freedom and roll freedom under all track conditions. That's my intention for my 0-6-2's, although I will also try a little optional springing of the body on the 4 top fulcrums, just to experiment with the running cosmetics.

Andy

proto87stores

Re: Flexi Chassis an Appreciation

Postby proto87stores » Mon Apr 10, 2017 11:56 pm

grovenor-2685 wrote:Ok search does reveal that you used 'impulse' in this message.but made it synonymous with a vague sort of bump.
I thought the layman "bump" was more generally understandable across the posting audience.

My apologies, I thought we were the audience.
I thought I'd taken pains to indicate that equalizing beams and fulcrums could be stacked (and added transversely) as well as paralleled to handle the general case.
I don't think there is any argument on that, the flexichas book, S4 digest and CLAG website do cover it all pretty thoroughly.
Regards


I apologize for any ambiguity. That was not in any way intended to offend. My hopefully by now understood goal is to show that there is a perfectly viable alternative method of 100% successful and dependable chassis construction for entry level, or less technically skilled, or less technically interested, P4 modellers. A method without the use or need for the complexities, extra work and know-how of primary springing. A method that in most cases, does not need the accuracy and alignment issues of working hornblocks. A method that builds on the prior straightforward and already well understood, methodology of Flexichas.

Unfortunately I do not have an equally easy method of mounting P4 wheels, or worse the thinner p:87 ones, accurately onto their axles. IMHO, that would also be an extremely positive chassis construction aid for members of both the P4 and P:87 communities.

Regarding the Digest. Back at the time when I first perused it, I never noticed any reference to the fundamental slight twisting of track on curved grades, nor any form of deductive comparison, whether regarding static cases or impulses or otherwise, that theoretically supported the progression from beams, to springy beams, to CSB's as providing increasingly better track holding. Mostly I saw the Digest as rightly pointing out the negative aspects of 3 point suspension, but only subsequently making merely assumptions that springing, and then CSB's, were obviously preferable to any form of beams, whether truly equalized or not.

Hence my concern that such comparisons have not been truly explored up to the present time

Andy

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Re: Flexi Chassis an Appreciation

Postby Crepello » Tue Apr 11, 2017 9:34 am

proto87 wrote:The 4 point body mounting would then instead be on the fulcrum centres of the additional upper side beams and the fulcrum centres of the two transverse beams. In that way the chassis also handles moderate twist, but still fully equalizes.


To be as analytically thorough as you wish the springing converts were, you need to quantify "moderate" please. Now that you have successfully reduced a six-wheel truck to four suspension points, how do you guarantee these four suspension points remain co-planar? If they don't, then loading is surely going to vary between any 3 of 4 rather than equalise?

billbedford

Re: Flexi Chassis an Appreciation

Postby billbedford » Tue Apr 11, 2017 9:48 am

proto87stores wrote:It''s not economic or as convenient to make long, strong, custom length, equalizing beams and their fulcrums for full size vehicles when springing wheels can be done much less expensively, and by using higher volume, lower weight, standard components. If you are considering human vehicles that also have "ground level entry" and/or "steering", then it becomes even more troublesome.


How is this different from a model? It seems to me that there is a good economic and convenience case to be made for using two fine steel CSB wires instead of filling the space between the frames with levers, that all have to be made to tolerance, and will take up the space that is better used for motor, gearbox, ashpan, motion plate, slide bars and possibly inside motion

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Compensation and Articulated Beams

Postby Lindsay G » Tue Apr 11, 2017 10:15 am

I find myself agreeing again with Bill (we were also in accord recently in disposing of miniscule amounts of flux). Here’s an item that I put together last night but didn’t get round to submitting :

I really must bar myself from reading endless threads, or articles, on articulated beams or attempts to improve upon rather out-dated compensated arrangements - such time-consuming distractions with lots of theory and counter theory but little substance. I can’t help but draw an analogy with an elderly die-hard trying to improve upon the gas mantle decades after the light bulb is invented.

No-one is ever going to conclusively win the debate on whether compensation or springing provides the better running and road holding– not within the printed word at least so I’ll leave that to one side. How about pondering the other major differences between a compensated system and a sprung one – flexibility, bulk, and visual impact. Within compensation you have a gearing arrangement on a fixed axle and elsewhere a rather large beam (or beams) arrangement, both just a tad unprototypical and nasty looking beneath the modelled boiler - what’s more, taking up valuable space better occupied by larger motors, pick-ups, lead, decoders, capacitors, cosmetic (or working) motion, etc., etc.. Have a look at those 3 Caley engines produced by Steve Duckworth in Snooze 201 (or engines by Steve and others throughout the Great 3F build off thread) and consider what the underside of the boilers would have looked like with a compensated arrangement in place. (Oh dear, lots of consideration might now be given to making compensated arrangements look better......please, no!).

Wouldn’t it be better to look forwards rather than backwards and get into debates on better understanding and appreciation of, or improving upon, sprung (or other yet to be devised) arrangements aiming for both superior running and appearance?

Helmet on, ducking for cover,

Lindsay

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Re: Flexi Chassis an Appreciation

Postby Armchair Modeller » Tue Apr 11, 2017 11:46 am

:thumb :thumb :thumb

I am sure that in general terms, both compensation and springing still have their place. There are undoubtedly bad springing arrangements and bad compensation arrangements, just as there are good ones of each - and many in-between. Arguing the absolute benefits of one system over another in the way many are advocating here though just gets us nowhere.

Well said, Lindsay!

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Re: Flexi Chassis an Appreciation

Postby Horsetan » Tue Apr 11, 2017 2:32 pm

Armchair Modeller wrote:.... Arguing the absolute benefits of one system over another in the way many are advocating here though just gets us nowhere. ...


It's not so much the arguing, more the sneering.
That would be an ecumenical matter.

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Russ Elliott
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Re: Flexi Chassis an Appreciation

Postby Russ Elliott » Tue Apr 11, 2017 2:50 pm

proto87stores wrote:Image

Here's how we can do a 6 wheel chassis. 6 wheel full equalization, then four point springing of each fulcrum to the frame. Four point sprung mounting over equalization gives 100% of the possible benefits of both equalization and springing.

Yes, good for 6-wheel trucks where the frame length is too short for a CSB, Andy. UK commercial implementations of drive bogies of such length, like Penbits, tend to be based on beam springs using the principle of the Digest's fig 51.


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