A strange tilt arrangement:
A - micro servo like Towerpro SG 50 or MG90S about 3 cm total length.
B & C- solenoid operated latches front & rear, release with power on. View attachment 102819 View attachment 102820

This is similar to what I had in mind, thanks.

 

For battery power LiFePO4 should work well, it is closer to NiCd as to charge requirements. & there is a
battery charge management control chip, MCP73223, 3mm X 3mm but there might be a breakout board available. 2 cells, 3.2 V, 1200 mAh, 18 mm dia. ,by 65 mm long. from onlybatteries.com.
I have ben using a similar set for about 9 months for my lighthouse, solar power home brew charger.
Might OR track power & battery into a buck convertor for 5 V, derive 3.3 V from 5V.

If I could have two sets of batteries, one charging while the other is in use, then automatically switching when required it would solve all the problems of picking up power from rails.

 

If I could have two sets of batteries, one charging while the other is in use, then automatically switching when required it would solve all the problems of picking up power from rails.

You would only need one battery, switching between two won't gain anything; there is only one source of energy.

 

You would only need one battery, switching between two won't gain anything; there is only one source of energy.

So I could keep the battery charged from the track 12v?

 

Yes. Re look at last line of post # 80. The buck convertor is about 2.5 cm wide, 2 cm tall, & 6 cm long.

 

So I could keep the battery charged from the track 12v?

Of course, energy is picked up from the track, some of that energy is used immediately and some is stored in the battery.

 

Actually, I conceded to using the superior ADXL335 accelerometer module over the opto-mechanical arrangement I originally proposed and my schematic incorporates this device.

The problem with your proposed passive tilting system is that the centre of gravity swings to the outside of the bend de-stabilising the car which is the exact opposite of what is needed.

The entire point of tilting the car, is to shift the cog toward the center of the curve, allowing greater speed by counteracting the outward force. A 'swing' would amplify the outward force and in the case of a model, provide very little counterbalance. Unless there was a static weight in the car... But this would destablize the car on straightaways. If you look at how the prototype does it, there are linkages connecting the carriage to the bogeys, such that the car itself becomes the pendulum.

From what little I've read, I thought that trains have been made to tilt for the comfort of passengers and the stability of packages and such, not to move the COG and improve balance.

As for the outward swinging, passive pendulum system, it's a real system in use on real trains:
http://web.talgoamerica.com/overview

 

OK, forgive the crudity of my drawing but this is what I meant by passive tilting. There are two train cars in the drawing. One with the pivot point very low and the other very high up (impractical too). Going around a corner the CG (the upper example) remains within the trucks (the bogey wheels) and is not destabilized. In the lower example the CG swings outside the trucks and topple over just like some have criticized my idea.

Thank you Wulf17 for vindicating my point with your link.

 

Thanks, I need to start work on the tilt mechanism, if I can't get that working then the rest is academic! Just need to find a scrap APT driving/trailer car that I can cut up.

G'day Peter

How much progress have you made on the tilt mechanism? While on holiday I had a thought on a tilt mechanism based on my experiences with rudder and tail wheel control. The servo I have used in the sketch is the Futaba S3114 micro servo. Since I don't have any OO gauge I used HO as the design basis, but this should put you in the ball park.

Any further thoughts on whether to proceed with a micro-processor solution? Remember if you are going to use a servo (which you should) you will need a PWM signal to drive it.

 

Re # 89, is 5 degree tilt enough? Nice drawing, wish we had a scale cross section drawing.

 

Re # 89, is 5 degree tilt enough? Nice drawing, wish we had a scale cross section drawing.

Don't know if 5 degrees will be enough - maybe 6 or possibly 7. Cant tell without a scale drawing of the car or having a car I can take measurements from. OO gauge is not readily available in the states.

 

Angles: We know that 90˚ is the same as 12:00 to 3:00. Therefore 30˚ would be from 12:00 to 1:00. Here's where I freely admit I don't KNOW this, but I'd assume that 30˚ (12 to 1) would seem like an extreme, but may be closer than we ( or I myself) might not realize.

Using Paintbrush, I've done scale drawings in the past. It requires laying out a measured grid knowing how many inches (or dots per inch) represents something in actual measurement. I've done rooms, buildings, furniture and stuff that way - without the aid of CAD-CAM or the likes. 7.5˚ would be like the movement of the hour hand where the minute hand has moved from 12:00 to 12:15. The hour hand would move 7 1/2 degrees.

 

Angles: We know that 90˚ is the same as 12:00 to 3:00. Therefore 30˚ would be from 12:00 to 1:00. Here's where I freely admit I don't KNOW this, but I'd assume that 30˚ (12 to 1) would seem like an extreme, but may be closer than we ( or I myself) might not realize.

Using Paintbrush, I've done scale drawings in the past. It requires laying out a measured grid knowing how many inches (or dots per inch) represents something in actual measurement. I've done rooms, buildings, furniture and stuff that way - without the aid of CAD-CAM or the likes. 7.5˚ would be like the movement of the hour hand where the minute hand has moved from 12:00 to 12:15. The hour hand would move 7 1/2 degrees.

Why guess? It would seem that the limit is somewhere around 6 degrees. The attached drawing shows the one I did previously but with the frame and servo arm tilted. Aint CAD great?

This would seem to be in line with the real world of model railroading. Have a look at the attached video. At around 3:05 you will see the APT on the inside track tilting inward as it goes around the curve (looks like #3 or larger radius). The angle of tilt looks to be somewhere around 6 degrees.

 

Skateboards. They tilt when you turn. OK, they tilt a fixed amount depending on the radius of the turn, and it won't be like the actual tilting cars but it WILL simulate the tilt. If the bogey's have their pins tilted on an as yet undetermined amount, the forward bogey tilted forward and the rear bogey tilted backward the same number of degrees then the car will tilt. On the straight-of-way's they will stand straight up.

I know, where's the fun in that?

 

According to this site, "It could tilt at an angle of 13°".

 

According to this site, "It could tilt at an angle of 13°".

That's on the prototype, on the model the tilt angle is constrained by the physical dimensions, i.e. interference between bogey and frame. Only the OP can tell us this info.
Also, the article refers to the Pendolino not the APT.

 

That's on the prototype, on the model the tilt angle is constrained by the physical dimensions, i.e. interference between bogey and frame. Only the OP can tell us this info.
Also, the article refers to the Pendolino not the APT.

The real APT-P had 9 degrees of active tile plus up to 3 degrees of passive tilt. I'm not sure yet how that will transfer to the Hornby model.

 

G'day Peter

How much progress have you made on the tilt mechanism? While on holiday I had a thought on a tilt mechanism based on my experiences with rudder and tail wheel control. The servo I have used in the sketch is the Futaba S3114 micro servo. Since I don't have any OO gauge I used HO as the design basis, but this should put you in the ball park.

Any further thoughts on whether to proceed with a micro-processor solution? Remember if you are going to use a servo (which you should) you will need a PWM signal to drive it.

Sorry for the delay in replying, I've been away.
I'm negotiating for a beaten up APT at the moment so as soon as I get that I will look into the feasibility of the tilt mechanism I have in mind.
I think I will go with the microprocessor solution as it seems pretty straightforward and compact. I'm thinking of battery power charged from the 12v DC track supply.

 

Sorry for the delay in replying, I've been away.
I'm negotiating for a beaten up APT at the moment so as soon as I get that I will look into the feasibility of the tilt mechanism I have in mind.
I think I will go with the microprocessor solution as it seems pretty straightforward and compact. I'm thinking of battery power charged from the 12v DC track supply.

Keep us posted. Once you have a solution for the tilter we can get into the details for the controls. Assuming you are going to use a servo, I suggest getting a cheap Arduino Uno from e-bay to use as your test bed and to familiarize yourself with programming basics. It's not that difficult once you get your arms around syntax.

 

Keep us posted. Once you have a solution for the tilter we can get into the details for the controls. Assuming you are going to use a servo, I suggest getting a cheap Arduino Uno from e-bay to use as your test bed and to familiarize yourself with programming basics. It's not that difficult once you get your arms around syntax.

I used to be an analyst/programmer so shouldn't be a problem, I'll let you know how I get on.