Dapol Streamlined Railcar

[swiftbeam]

Yes, 11.6mm

[bertiedog]

Well, maybe a faulty winding in one pole, but you mentioned fitting the U/J shaft in one of 8 positions? Is it in a multi sided socket at the motor end?

 

And the other end is a ball and pin u/j?

 

Then one end is sort of a c/v joint and it is absolutely critical to set them out of phase, or else you have a Hookes joint, which will produce exactly the trouble you have.

 

It will be the bogie end that needs turning on the shaft till a sweet spot is found where the joints cancel out the hunting.

 

This is the kind of mechanical mistake that could slip in at the factory, and explain all the problems.

 

Stephen

[swiftbeam]

No, you have misread what I said, I said "I've just checked the drive shaft at 1/8th intervals, all nice a free, no tight spots."

 

That is to say, I turned the motor over 1/8th of a turn and felt for slop in the UJ and shaft, then another 1/8th of a turn etc until a whole rev was made (8 pints of checking) There is only one slot in the flywheel and one slot in the bogie drive cup. So the factory is in the clear :-)

 

The model is now set aside until the Mashima motor and bogie is here. Once I have tested the motor and maybe resorted to fitting the Black Beetle, I will report my findings. Maybe the motor will fix it? But I think we all know that if the Black Beetle goes in, it's game over, totally towel thrown in and job done.

 

The problem with fixing it with the BB is nobody will know for sure where the problem is, but really that's Dapols problem not mine, and I'll finally have a nice Railcar, all be it costing me £220!

 

I think I've taken up far too much of this thread now and I don't suppose I'm Dapol's favourite customer.

I'll just post one more time, the post that has fixed my model.

 

This is to say nothing of my Daopl 52 that has been sent back twice for wonky wheels!

If she comes back with working wheels again, I'll make a jig and skim the treads myself on my lathe! (Axles and wheels in situ)

 

Thank you for everybody's support and ideas here, you've been great.

 

See ya for now.

 

Thank you 

Edited November 6, 2017 by swiftbeam

[charliepetty]

No, you have misread what I said, I said "I've just checked the drive shaft at 1/8th intervals, all nice a free, no tight spots."

 

That is to say, I turned the motor over 1/8th of a turn and felt for slop in the UJ and shaft, then another 1/8th of a turn etc until a whole rev was made (8 pints of checking) There is only one slot in the flywheel and one slot in the bogie drive cup. So the factory is in the clear :-)

 

The model is now set aside until the Mashima motor and bogie is here. Once I have tested the motor and maybe resorted to fitting the Black Beetle, I will report my findings. Maybe the motor will fix it? But I think we all know that if the Black Beetle goes in, it's game over, totally towel thrown in and job done.

 

The problem with fixing it with the BB is nobody will know for sure where the problem is, but really that's Dapols problem not mine, and I'll finally have a nice Railcar, all be it costing me £220!

 

I think I've taken up far too much of this thread now and I don't suppose I'm Dapol's favourite customer.

I'll just post one more time, the post that has fixed my model.

 

This is to say nothing of my Daopl 52 that has been sent back twice for wonky wheels!

If she comes back with working wheels again, I'll make a jig and skim the treads myself on my lathe! (Axles and wheels in situ)

 

Thank you for everybody's support and ideas here, you've been great.

 

See ya for now.

 

Thank you 

Black Beetle's have stopped being made I am affraid.    Charlie

[melmerby]

Black Beetle's have stopped being made I am affraid.    Charlie

Still being advertised.

 

Keith

[Prometheus]

 

 

I think I've taken up far too much of this thread now and I don't suppose I'm Dapol's favourite customer.

I'll just post one more time, the post that has fixed my model.

 

 

 

Not at all. I am genuinely sorry for your woes - it must be hugely frustrating, and expensive. But this has been an interesting discussion and as an exposition of forensic engineering, it takes some beating!

 

Tony 

[dibber25]

When talking of 'hunting' are you guys referring to jerkiness in running or to 'hunting' as it would be on the full-size railway? i.e an undesirable bogie movement? (CJL)

[Prometheus]

When talking of 'hunting' are you guys referring to jerkiness in running or to 'hunting' as it would be on the full-size railway? i.e an undesirable bogie movement? (CJL)

 

Correctly or not, I always view 'hunting' as a tendency to lurch forward somewhat.

 

Tony

[railcar1]

As mentioned in my previous post my railcar surges.Being pedantic this is not hunting but we are all talking about the same phenomenon. Having returned the railcar I await its replacement with interest.

[ROSSPOP]

Correctly or not, I always view 'hunting' as a tendency to lurch forward somewhat.

 

Tony

 

Yes that`s how I would describe it...........  surging or lurching when there is usually a mismatch between the motors responce to what the controller is doing..... ie between a coreless motor and a controller with a modicum of feedback. Often the motor is somewhat noisy in performance.

 

so using the right kind of controller (DC) or a better quality decoder ( with motor control ) will help improve performance.

 

In both 4mm and 7mm I have always used Zimo decoders that  usually automatically adjust to  optimum motor control but when using Maxon coreless motors I often need to tweak several CV`s to elliminate surging.  I also had to tweak CV`s on Bachmann 3pole motors.

 

John

Edited November 6, 2017 by ROSSPOP

[dibber25]

Have now test-run mine both at home and on the Model Rail test track and no problems - smooth throughout the speed range. Both layouts have Gaugemaster controllers, though different types, the Model Rail one being a rolling road unit. (CJL)

[railcar1]

Good to hear this.Which type of gaugemaster,pure dc or feedback?

[Prometheus]

The club's website article for those who may be interested. These are not intended to be belt-and-braces reviews but are posted for general information and to keep the website fairly dynamic and up-to-date.

 

https://srmg.org.uk/news-blog/2017/11/6/review-Dapol-00-flying-banana

 

Tony

[charliepetty]

Still being advertised.

 

Keith

Yes, some are left in stock, not many though.    Charlie

[melmerby]

Yes that`s how I would describe it...........  surging or lurching when there is usually a mismatch between the motors responce to what the controller is doing..... ie between a coreless motor and a controller with a modicum of feedback. Often the motor is somewhat noisy in performance.

 

so using the right kind of controller (DC) or a better quality decoder ( with motor control ) will help improve performance.

 

In both 4mm and 7mm I have always used Zimo decoders that  usually automatically adjust to  optimum motor control but when using Maxon coreless motors I often need to tweak several CV`s to elliminate surging.  I also had to tweak CV`s on Bachmann 3pole motors.

 

John

I have a Lenz Controller and I have fitted the railcar with a Lenz Silver + decoder, at least the equal of a Zimo decoder. (Apart from adjusting the top & midrange speed to suit they normally work "straight out of the box")

I always set acceleration and deceleration to zero. (leave that to TranController) I don't alter feedback. I don't use custom speed tables.

I use Traincontroller and consistent operation is essential but the Railcar is as it stands, unusable.

 

My extensive roster of Bachmann locos all have default settings apart from setting speeds and address and they all work fine (Lenz decoders exclusively) IIRC all Bachmann locos are (were?) three pole.

Never had to faff around tweaking settings on anything but a bad (e.g.old!) loco, so having a problem with a brand new design means there is definitely something amiss with the drive train.

 

I feel like trying the Railcar with one of the TCS decoders I removed from other locos to see what it is like with one of them with their (IMHO) inferior control.

 

Keith

Edited November 6, 2017 by melmerby

[Prometheus]

As requested, I ran my model again at the club tonight, on analogue, through 10% speed increments up to flat out. No hunting was observed at all.

 

Tony

[Irishrailwaymodeller]

Does anyone know if Dapol plan to do equivalent N and O gauge versions of this model?

[Karhedron]

Does anyone know if Dapol plan to do equivalent N and O gauge versions of this model?

People have asked but I am not aware of them publicly stating anything to confirm or deny it. I would be up for a couple of N gauge ones myself. All we can say for sure is that they know enough demand exists for people to inquire. I guess we have to wait and see.

[woodenhead]

Interesting that Dapol hold the keys to a few models in other gauges - the Autocoach and B set from O down to 4mm and the railcar up to O - N gauge I suppose will be an interesting test of commitment to the gauge outside of models already planned.

[melmerby]

Interesting that Dapol hold the keys to a few models in other gauges - the Autocoach and B set from O down to 4mm and the railcar up to O - N gauge I suppose will be an interesting test of commitment to the gauge outside of models already planned.

The Dapol (/Lionheart) panelled Autocoach really looks the part and a 4mm version would IMHO sell well.

 

Keith

[swiftbeam]

Hi Guys,

 

I know I said I'd not post again until the final report.

 

But just want to say the work has be done, and I have an answer and pics.

 

It will all be written up and posted in the next day or so.

[swiftbeam]

If you are a new reader to this thread, please read all pages going back to at least page 26 so you have a CLEAR understanding of what has already been tested. 

 

PLEASE NOTE ALL OF THE BELOW IS ONLY MY PERSONAL OPINION AND IS IN NO WAY TRYING TO CONTRADICT Dapol's DESIGN. I MAY JUST HAVE HAD THE ONLY THREE ENGINES IN THIS PRODUCTION BATCH THAT FALL BELOW MY PERSONAL STANDARD? ALSO I CAN IN NO WAY SAY WHAT WOULD HAVE BROUGHT THE TWO MODELS I SENT BACK TO THE SHOP UP TO MY PERSONAL EXPECTATION AS I NEVER LOOKED INTO THOSE MODELS.

 

OK Guys,

 

Here we have my final comment and conclusion of my personal Dapol Railcar in regards to its 'Hunting' issue I personally feel it had.

Hunting occurs at about 40% DC and 50% DCC, it is most noticeable on DCC, and this speed is exactly were most of us would perceive about 30mph to be in real life. This problem was present in all three of my Dapol Railcars. I have kept one and returned the other two as I only have the 'head space' to fix one problematic model.

 

When the model travels up hill, the hunting stops, when travelling down hill, the hunting stops, when against the buffer stops and wheels are slipping on the track the hunting stops. While hunting, you can hear the motor change revs or react to load change.

 

So a new Mashima 1628 motor was fitted and a new flywheel/drive cup was made. As some on this thread have already suggested may be the case, this motor change did nothing to solve the issue. So at this point all I have is the un-driven bogie collecting power, bigger wires fitted to this bogie and feeding the new motor directly. All that remained of the original Dapol System is the drive shaft, UJ and power bogie (not collecting power) and still the hunting persists. The UJ was ruled out as an Extra 0.007" shim was added to remove all traces of worm backlash. I think it is at this point safe to say my problem is in the driven bogie as there is simply nothing else left.

 

The problem was totally resolved by fitting a 26/12 Black Beetle bogie. This size is a tad short, but beggars can't be choosers when these power bogies are not made any more. 28/11.5mm is an exact match for the Dapol Railcar, but because you can't see the bogie, 2mm in length is not an issue. The difference in wheel size is also irrelevant because you have to 'make' the bogie fit, thus setting the ride height yourself. As I just stated, these bogies are no longer made, but some do still remain in stock if you hunt about. The other option would be a Tenshodo Spud , 'word on the street' is that these bogies are not the best, but I can't comment as I've never had one. There is also the Hornby or Bachmann option with something 'borrowed' from a DMU/EMU.

 

The model now runs without fault and is how I always wanted it to be. The up side is not only does the model run well, I've been able to remove the 'motor bulge'. The interior is in grey primer for now, but will be painted in the appropriate colours at a later date.

 

I am not a professor of engineering, so I can not 'tell' you why the problem with hunting is in my model, but I believe the issue lies within the gear train of the driven bogie. Excluding the worm and UJ's, there are 8 gears in total involved in taking the drive down from the worm to the wheels. In one of my wheels, I had 1/8th of a rev in free turn, and the other had only 1/16th of free turn. I don't know what that means in terms of drive, but the free rev in each wheel is not the same due to the uneven number of gears either side of the 1st driving cog from the worm. Over the 8 gears, there are 8 points of gear backlash. 

 

I think at low and high speed the bogie is pushing the body, but at mid speed, the backlash in the long drive train is having an influence. Maybe the gears push the body forward and the body takes up the backlash having been pushed by the gears, then coasts until it slows enough for the body to be pushed again by the gears? Maybe the weight of the body and the backlash in the gears is just enough to set off a harmonic oscillation when the drive train is at coasting speed.

 

I don't think the motor is being back driven by the bogie gears as the worm cannot be driven from the bogie side of the drive train. However, the fact that the motor is being affected during the hunting may be messing up whatever system is in play within the DCC system. I believe the DCC system uses some sort of feedback from the motor to control the speed, so a motor being forced to change its speed because of the drive train may explain why the hunting is more noticeable in DCC? Ironically, a flywheel will make hunting worse in this case as it is using its momentum to load the motor, and this is something else the DCC has to try and smooth out.

 

DC being a pure voltage, the controller is not trying to adjust for anything, the loco just reacts to the given voltage (assuming you are not using force feedback) So the hunting will show less.

 

If the above is correct, then very thick grease in the gearbox would help, or a much heavier body so the drive train is under load for longer, or some sort of brake giving resistance to the wheels. Unfortunately, all of these options will put the drive train under excessive load and cause damage. If my thoughts are correct, the model simply needs a better fitting set of bogie gears or a less convoluted or evenly spaced gear drive train.

 

AGAIN, MY PERSONAL THOUGHTS.

 

THERE IS A REAR BEARING ON THE WORM, JUST MISSING FROM THE ABOVE PICTURE!

 

Edited November 12, 2017 by swiftbeam

[The Johnster]

The Dapol (/Lionheart) panelled Autocoach really looks the part and a 4mm version would IMHO sell well.

 

Keith

 

 

I would certainly be in the market for a diagram N autotrailer, and possibly a B set but it would have to be very good to justify the probable cost.  I'd be more interested in any other sort of GW non gangwayed coach.

[Miss Prism]

An excellent analysis, swiftbeam, and similar to the phenomenon described for the Hattons 48xx. See:

http://www.rmweb.co.uk/community/index.php?/topic/92852-hattons-announce-14xx-48xx-58xx/?p=2776764

 

 

[railcar1]

If you are a new reader to this thread, please read all pages going back to at least page 26 so you have a CLEAR understanding of what has already been tested. 

 

PLEASE NOTE ALL OF THE BELOW IS ONLY MY PERSONAL OPINION AND IS IN NO WAY TRYING TO CONTRADICT Dapol's DESIGN. I MAY JUST HAVE HAD THE ONLY THREE ENGINES IN THIS PRODUCTION BATCH THAT FALL BELOW MY PERSONAL STANDARD? ALSO I CAN IN NO WAY SAY WHAT WOULD HAVE BROUGHT THE TWO MODELS I SENT BACK TO THE SHOP UP TO MY PERSONAL EXPECTATION AS I NEVER LOOKED INTO THOSE MODELS.

 

OK Guys,

 

Here we have my final comment and conclusion of my personal Dapol Railcar in regards to its 'Hunting' issue I personally feel it had.

Hunting occurs at about 40% DC and 50% DCC, it is most noticeable on DCC, and this speed is exactly were most of us would perceive about 30mph to be in real life. This problem was present in all three of my Dapol Railcars. I have kept one and returned the other two as I only have the 'head space' to fix one problematic model.

 

When the model travels up hill, the hunting stops, when travelling down hill, the hunting stops, when against the buffer stops and wheels are slipping on the track the hunting stops. While hunting, you can hear the motor change revs or react to load change.

 

So a new Mashima 1628 motor was fitted and a new flywheel/drive cup was made. As some on this thread have already suggested may be the case, this motor change did nothing to solve the issue. So at this point all I have is the un-driven bogie collecting power, bigger wires fitted to this bogie and feeding the new motor directly. All that remained of the original Dapol System is the drive shaft, UJ and power bogie (not collecting power) and still the hunting persists. The UJ was ruled out as an Extra 0.007" shim was added to remove all traces of worm backlash. I think it is at this point safe to say my problem is in the driven bogie as there is simply nothing else left.

 

The problem was totally resolved by fitting a 26/12 Black Beetle bogie. This size is a tad short, but beggars can't be choosers when these power bogies are not made any more. 28/11.5mm is an exact match for the Dapol Railcar, but because you can't see the bogie, 2mm in length is not an issue. The difference in wheel size is also irrelevant because you have to 'make' the bogie fit, thus setting the ride height yourself. As I just stated, these bogies are no longer made, but some do still remain in stock if you hunt about. The other option would be a Tenshodo Spud , 'word on the street' is that these bogies are not the best, but I can't comment as I've never had one. There is also the Hornby or Bachmann option with something 'borrowed' from a DMU/EMU.

 

The model now runs without fault and is how I always wanted it to be. The up side is not only does the model run well, I've been able to remove the 'motor bulge'. The interior is in grey primer for now, but will be painted in the appropriate colours at a later date.

 

I am not a professor of engineering, so I can not 'tell' you why the problem with hunting is in my model, but I believe the issue lies within the gear train of the driven bogie. Excluding the worm and UJ's, there are 8 gears in total involved in taking the drive down from the worm to the wheels. In one of my wheels, I had 1/8th of a rev in free turn, and the other had only 1/16th of free turn. I don't know what that means in terms of drive, but the free rev in each wheel is not the same due to the uneven number of gears either side of the 1st driving cog from the worm. Over the 8 gears, there are 8 points of gear backlash. 

 

I think at low and high speed the bogie is pushing the body, but at mid speed, the backlash in the long drive train is having an influence. Maybe the gears push the body forward and the body takes up the backlash having been pushed by the gears, then coasts until it slows enough for the body to be pushed again by the gears? Maybe the weight of the body and the backlash in the gears is just enough to set off a harmonic oscillation when the drive train is at coasting speed.

 

I don't think the motor is being back driven by the bogie gears as the worm cannot be driven from the bogie side of the drive train. However, the fact that the motor is being affected during the hunting may be messing up whatever system is in play within the DCC system. I believe the DCC system uses some sort of feedback from the motor to control the speed, so a motor being forced to change its speed because of the drive train may explain why the hunting is more noticeable in DCC? Ironically, a flywheel will make hunting worse in this case as it is using its momentum to load the motor, and this is something else the DCC has to try and smooth out.

 

DC being a pure voltage, the controller is not trying to adjust for anything, the loco just reacts to the given voltage (assuming you are not using force feedback) So the hunting will show less.

 

If the above is correct, then very thick grease in the gearbox would help, or a much heavier body so the drive train is under load for longer, or some sort of brake giving resistance to the wheels. Unfortunately, all of these options will put the drive train under excessive load and cause damage. If my thoughts are correct, the model simply needs a better fitting set of bogie gears or a less convoluted or evenly spaced gear drive train.

 

AGAIN, MY PERSONAL THOUGHTS.

 

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