Bringing the AA20 (Andrey Andreev 20 ton per axle) back to life...4-14-4

[justme igor]

I think this is the right section of the forum?

. . . . . . . ........... Total hours (re)designing: 108
. . . . . . ............. Total hours printing: 45
. . . . . ................ Total hours of tinkering: 8

I finally started with designing and building the AA20.
I thought it would be nice to share this build from the first hour to the first meter of driving.
There will be 2 versions made, both will be prototypical 100% correct.
1 will be 3d printed with all the accurate details.
2 will be a live steam one.
I need to make the files anyway to make/create for the casting.
The live steam loco will be a follow up or a different topic.
It is in scale 1/32 a whooping 1 meter 5 cm and 4 mm or for those imperial 41,49 inch from coupler to coupler

I really dont know what the smallest radii she must have, but i guess 3 meters minimum, my biggest curve is 4 meters, wish me luck on this one.

I just completed the housing for the engine, the first print will be in pla incl the wheels.
If the whole thing will drive on a certain curve I will make her in abs.
In the pictures on the key board you will see a (~failed) experiment, but it will give a impression of what this is all going about.

View inside the moterhome/motor house.



Disassembled ready for pins and glue after the motors are fitted and soldered.


A ruff total view to give a impression.

Sinds i suspect this is going to be a long thread and to keep it a bit clean i will place my updates in this first message.

I hope you will enjoy and appreciate that i am sharing this project.
There where just 3 others before me that completed this loco 1 for selling btw



Update as 9 feb 2021,Update as 9 feb 2021



As you can see i had to redesign the motor home, it was just to short for the electro motors





For the front support i had to make up a sort of connection, my printer bed is just not long enough in diagonal.
Sinds this is also a rigged frame this brings in some very mechanical challenges, i am having fun.
The front boogie is going to be attached to the upper frame and will get a left right guidance.
This will be probably need lithium grease.
Sinds the front of the boiler is also resting with his weight it must have a smooth bearing surface
The rear support will get probably the same construction for distribution of its weight, but will be connected as a trailer.
Even in abs with some electronics, motors and li ion cells, i think this will be a heavy one.
Good for the traction
The bottom side of the motor house is now printing.
Experimental in pla.

I finished all the wheels:



I printed the first and the third wheel a couple of times and mounted them on the test frame.




The test wheels were ~satisfactory....pla is not my material and the printer is fine tuned for abs....
In the test setup all went oke but the drive not so well.
Between the rail and the flange i have just 0,5mm clearance, total of 1mm, works very good for small locos and cars, but not for bigger sizes.
The wheel/drive shaft connector will be a 0,5mm shorter, i can go to 1mm before i will get trouble with my frogs, probally going to widen them from 2.2 mm 30mm....
That kind of clearance is doable with prototypical correct....


With best regards Igor


Update as per 14-feb-2021



Almost forgot the fun of soldering...

Not really happy:

Some wheels are missing.

Problem to get the axles presses into the axle holders and wheels, will figure this out


This is going to be big....
.
.
.
For Greg:
Yes i use prototypical and g1mra specs:

This can work

Ofcourse this wont work......

Will do greg....it will do

Sorry i did not post earlier, i was real pretty really busy...making snowman, throwing snowballs, acting like a teenager again, but having a own company?!?!?!?!......sipping brandy and quality wiskey (macallan 30 yr i can recommend!)by the fireplace, walking dogs in the snow...those kind of things busy.....
Till so far my lies and deception...This was my progress on the AA20 so far, any comment, thought or idea is welcome.

It is one stubborn B......
She will not go over 3 meter radii curves, the reason why it was one big failure is coming floating above water....

Even reducing the width to 41mm flange to flange is not helping to take a 3 meter radii, and this is not even with the front or back support!

This is with thin wheels, i will try wheels with 7mm instead of 5mm thickness.....
Keep it prototypical....I tried curves with a raddi of 4 meter...~that ~goes ~well....big bed sheeeeeet
I can not add more than 20 pictures... i will proceed in a other post, sorry

With best regards Igor

 

[dunnyrail]

Wow, I think a worthwhile quick excersize may be to cut a piece of wood the length and width (inside the wheels) of the fixed wheelbase. You could pop this on top of the track at your 4 metre radius to see how it looks. If the overhang is too great you may need to consider doing an LGB where the 2-10-2Tank chassis is actually a 2-6-4-2 with double motors and a layshaft joining the two. Piko do a similar trick on their 2-10-2Tank.

 

[David1226]

Wow, I think a worthwhile quick excersize may be to cut a piece of wood the length and width (inside the wheels) of the fixed wheelbase. You could pop this on top of the track at your 4 metre radius to see how it looks. If the overhang is too great you may need to consider doing an LGB where the 2-10-2Tank chassis is actually a 2-6-4-2 with double motors and a layshaft joining the two. Piko do a similar trick on their 2-10-2Tank.

I think you articulated that idea very well.

David

 

[justme igor]

ow, I think a worthwhile quick excersize may be to cut a piece of wood the length and width (inside the wheels) of the fixed wheelbase. You could pop this on top of the track at your 4 metre radius to see how it looks. If the overhang is too great you may need to consider doing an LGB where the 2-10-2Tank chassis is actually a 2-6-4-2 with double motors and a layshaft joining the two. Piko do a similar trick on their 2-10-2Tank.

That is exactly the plan, to cut pieces of wooden sheet at the size (width and length) of the loco to observe the overhang and how to "execute" the connection with the tender.
The problem with making as a lgb or the pico example would be the driver rods.
Sinds i am building it from nothing i can smuggle a bit with the driver weels axles and the flanges, this could give that bit of clearance if it wont go around 3 to 4 meter raddi.
3 meter raddi is the first goal, but if it looks to funny or out of proportion i must adjust my track plan that my outer track will have a minimum of 4 meters incl turnouts crossovers ect.
To bad that i could not fit in more motors(2 extra) to make her a bid more powerful, it could be done if i was willing to enlarge the loco with 5.8 cm....
But if 2 of those motors can pull 10! kg easy, i am not so worried about the pulling force, traction can be improved if neccecery with extra lead dead weight.

EDIT:
Did some recherche: one motor can pull 9 kilo WOW, they are rated for 800gf?

Thanks

 

[Timmo]

Brave man. What a beast, but I look forward to seeing it running!!

Tim

 

[justme igor]

My dear boy Tim
There where longer ones (successful ones! in a later period us of a)...in non articulate frames on my wish list....not only garrets.
Big joe was a garret type btw......this one would count as the longest and strongest loco ever be built for steam power---> nuclear but oke

 

[Greg Elmassian]

some long steam models had hinged siderods, and axles that can move sideways a lot, the combination allowed tighter curves.

Greg

 

[Paul M]

Wow, that is going to be something worth seeing! I'm looking forward to the results, especially the live steam one, where will you run it, it will need a long run to get going

 

[justme igor]

I will run it in my garden, the outer rim/track/oval is going to be ~ 400 meters in lenght with a minium raddi of 3 meters.
I hope she is able to take those curves, if not i have to redesign/enlarge two corners of the outer oval, we will see.
The steam one will be done i think somewhere in 2023, could be summer 2022 or even summer 2024.

 

[justme igor]

Updated the first post in this thread with my progress on the aa20.
Comments ideas thoughts ect are welcome

 

[Greg Elmassian]

From your update, are you really trying to use prototype dimensions for your wheels, flanges, and wheel gauge?

Maybe you could share your back to back gauge, flange thickness, flange depth, and gauge, since you do not seem to be following any model railroad standard.

I can tell you for sure that those flanges are not deep enough for that length of loco, no matter how you spring it.

Greg

 

[justme igor]

UPDATED my first post with some progress....
Maybe next week a first drive????with all the wheels incl front+back boogie and the tender just to see how she would drive on a 3 meter radii curve....MAYBE----> if time permits.....AND only the wheels, i dont want to create false hope, but I CAN NOT wait

with best regards Igor

 

[Tropic Blunder1]

Looks amazing Igor its a fantastic prototype

 

[Greg Elmassian]

OK, so how will you keep the individual motors synchronized? I don't see that this is practical, so will the siderods not connect to all drivers?

I see 4 drivers will be powered.

I really do not see how it will work mechanically.

I can see that you can have 3 drivers idling, but still without mechanical synchronization, 2 powered axles should be an issue, not to mention 4.

What is your strategy? I'm really curious.

Greg

 

[justme igor]

The side rods will connect all the wheels.
All the motors are the same, i am waiting for a batch(20x) from China so i can pair them if necessary.
In the event that the motors will not be at the same speed/tork, this will not be a mechanical problem.
A motor needs a certain amount of power.
If one motor is stronger/faster he will give a bit more and use a bit less mA to let the weakest/slowest will use a bit more in mA to stay in line due to the side rods.
Mechanical speaking: they will balance each other out in the delivered force and act as one single motor.
But without connection to the side rods they will of course act like 4 different motors.
For better traction i will connect all the 7 wheels to the rod
They put in the same effort in the end to get all the rolling stock moving.

 

[Paul M]

The side rods will connect all the wheels.
All the motors are the same, i am waiting for a batch(20x) from China so i can pair them if necessary.
In the event that the motors will not be at the same speed/tork, this will not be a mechanical problem.
A motor needs a certain amount of power.
If one motor is stronger/faster he will give a bit more and use a bit less mA to let the weakest/slowest will use a bit more in mA to stay in line due to the side rods.
Mechanical speaking: they will balance each other out in the delivered force and act as one single motor.
But without connection to the side rods they will of course act like 4 different motors.
For better traction i will connect all the 7 wheels to the rod
They put in the same effort in the end to get all the rolling stock moving.

I hope you are right I your calcuations, but you might find that if there's a slower motor it will cause something to bind. Hopefully not though

 

[Greg Elmassian]

being geared motors, they can get out of sync for sure.

The question is the gearboxes (assuming your siderods and crankpins and the wheels themselves can handle the torque).

so, with these gearboxes, if you turn the wheel, does the motor shaft turn easily? If not, I guarantee you will have problems, at the very least binding that will affect performance.


Greg

 

[justme igor]

I am not really afraid of that,we will see.
I was already thinking about that problem, but that problem if it is going to be one is a far away one.

The next problem i have to bend my head at is the curve, it wont drive on 3000 radii curves/6 meter diameter, bur 4 or even 4.6 meter radii curves in prototypical design
Updated my first post

 

[justme igor]

Since i could add no more to the first post i try to continue here as a second post.
Here she is on a 4 meter radii curve/8 meter in diameter.....

You see clearly the "hovering/floating" of the unflanged wheels on a 4 meter radii track


The unflanged wheels do there job very good.
In the front of the picture you see a wooden thing, that thing represent the FULL AA20 with hinges at the correct places, she is big/tall/long.....and not even a fat a**

The piece in the middle is only the tender, 39.1 cm long, the 2 piece down below are representing the tenders boogies, the screw is not at the prototypical plcse as a hinge, but my feeling tells me if it is going to work it must be there...oke next
From the first hinge of the loco to the first one of the tender aroend 60 and 80 cm respectively.

Last 6 axles are tender, two on the left are for the back support.

The seven in the middle are for the loco itself and two on the far left are for the front support.
This week i hoop to achieve to attache the wheels to the wooden full lengths frame and see how she is going to behave on a 4 meter curve.......
To save room on this server, i did not attach pictures of her and going over a frog, but for me it is obiuse why it was a driving disaster...
She needs for a good and smooth drive her own frogs and turn outs to her specifications.
I wont change anything and keep her as close as possible to prototypical correct.....
However this could mean a minimum curve of a 4 meter 60 radii and i have to adapt my garden for this, with wheels that are not prototypical correct: g1mra.
There are more hinges and side clearance in the proto type than you would think.


The experiment with the beer cans rolling stock was close to the dimensions of the boiler(7.5 cm in diameter and 56 cm long, cans are 51 cm long), in this picture no tender or cab, only front and back support with loco drivers incl boiler.....
Someone mentioned that i must do a experiment in wood to keep it cheap and simple to see how she would behave on the tracks....V E R Y clever thinking, thank you very much, no....double thanks and thumb up for you, as you can see i am busy with it, now i must have time to get some results
To be continued....in steam...i doubt it, but i will go for it, that is for sure

 

[Greg Elmassian]

I am not really afraid of that,we will see.
I was already thinking about that problem, but that problem if it is going to be one is a far away one.

The next problem i have to bend my head at is the curve, it wont drive on 3000 radii curves/6 meter diameter, bur 4 or even 4.6 meter radii curves in prototypical design
Updated my first post

So, I am trying to understand the last sentence.

So you say the model won't work on a 6 meter diameter curve - which is 20 foot diameter (not surprised)

But you say the prototype will function on a 4 meter radius, i.e. 8 meter diameter - which is 26 foot diameter...

And you show a picture of your model on a 4 meter radius, 8 meter diameter, and the center drivers are way off the rails.

OK, so if I made a mistake in the 3 sentences above... tell me... otherwise, I am not the least bit surprised at the model and the picture.

Reference post 7 on hinged siderods... now you need more lateral travel in your drivers, or a hinged frame.

If you don't want to make a hinged frame (reference post #2), then look at how Aristocraft handled this (wide worm gears that allow lateral motion in axles).

I would suggest you consider copying what they did if you don't want to hinge the frame.

I have a 2-10-2 that will travel on 5 foot radius curves built from Aristo gearboxes, and the design is modular, i.e. more gearboxes can be added easily.

Greg