Thanks, I'll post the calc up later on as i have visitors arriving.
Don't worry the calc is relatively simple, you will need to know the following information prior to the calc.
1) Weight of vehicle, supported by x wheels (i.e. wheels in contact with the ground).
2) The amount of twist in degrees, (this will set the pre-twist limit).
3) length of torsion bar (this is critical and is usually determined by the width available to accomodate it) for the warrior i have it as 265mm.
If you have MathCAD I can email the spredsheet I made or i could print it out and post it to you.
Failing that if you want supply me the details above and I'll do the calc for you, should take about 30secs!!!
At the moment i'vent real data spec to give you , im in predesign phase but to give you an idea im working on a Tiger B (KT) in 1/4 scale ( i hope so ) near 400-500 Kg ( i prefear 400 kg) so if we do a theorically calc :
- We have 9 suspended whell by side
- the 1:1 length size of KT is about 7.80 meters so 1.9 meters in 1/4 scale
- width is about 1 meters in 1/4 scale ( so imagine 50 cm allowed to torsions bars
-some one knows KT torsion bar free radius range?
hope this will draw you the context
Looking at your specs I and considering your at pre-design stage, I think it would be of more benefit to you if you get the calc and work out your own variables yourself as you thrash out your model design.
One other critical dimension you need to know is the length of the swing arm, as this will define the torque value applied to the torsion bar.
I'll post a drawing / calc sheet up later this should help you. check back tonight / tomorrow and it should be posted (I'll edit this post).
Hope this helps
Where's the baby manual!!!! Harrys fine by the way but it does come as a shock just how little time you have to yourself!!!!
rtal, I have emailed you the calc sheet for you, I can't post it up here as every time I save it as a jpeg the resolution plummets and it becomes unreadable, as you yourself found out!!!!
The tank fan, hope you get the beastie running, maybe you can post some pictures of the machine, maybe you should start a thread like this and post pics of the build etc, I am sure loads of people would be interested in seeing the pics, myself especially!!!
Well the Warrior project has / is creeping along nicely, the wife and the wee one head to there bed quite early so it allows daddy a chance to work in the shed or on the laptop!!!
Check out the pics below to see the latest new stuff made!!
Idler Wheels at the machinists:
The idler wheels and outer track carrier wheels at the machinists:
Close up of Idler wheels:
Close up of outer track carrier wheel:
Some more cad dwgs, added the crane assembly, am working on the rear stabiliser leg and the method of which the crane will work. I'm considering hydraulics (from the german company Leimbach Modellbau) Pneumatics, and electric motors and leadscrews! any input on this would be very welcome.
My gut instinct at the moment is to use Pneumatic rams, and camouflage them to look like hydraulic rams where necessary. My only problem is the rear stabiliser leg on the warrior, as a ram will be difficult to mount, I am considering a rack and pinion action to do the same job........as yet not sure how to to solve this problem!!!
I'm still waiting on a few more parts to be finalised before getting them made, my intention was to have the running gear, including the tracks complete by the end of the year, so far so good, although you never know what might crop up and sting you...........
Anyway, hope you enjoy the pics!!
Constructive critisim as always - most welcome.
Andy & Harry
Appreciate your comment, I am getting particulary proud of this little ( ) machine.
I got another parcel of parts today for the balance of the swing arms that I'm outstanding. So I should be able to do the machining tonight and maybe have some more pics to post by the end of the week. My sprocket design is out for quotation as well, so maybe have that squared away soon too.
I'll post a link to my machinist mate, as he has stated his interest in doing more work of this kind, so if anyone is interested check out the for-sale section.
I was wondering, how much you machine shop charges. I went to Emachineshop, and designed some parts, and the price was way more than I want to pay. I designed for example a sample[very simple}roadwheels for a 1/6 Panzer IV, and they wanted like $600+ usd for them
Can you give me an idea, like say how much you paid to have your spoked wheels made? or other parts?
BTW beautiful stuff your making there!
For the idler wheels I was quoted Â£150ea to to be CNC machined, expensive for a on-off although the price per unit would drop should you be planning to build a few model......
In the end I used a machinist (D M Machining)who advertised in model engineer this is a bi-monthly UK magazine. I have posted Mike contact details in the for sale section.
The cost per idler was much cheaper, around Â£80 for the machining work. To be fair they are far more accuarte then what I really needed. In hindsight I could have made the wheels myself with a bit of cunning........however I don't have the luxery of time to play in the shed as I did a few months ago
Much more fun playing with my son Harry (17 weeks) 8) 8) 8) 8) 8) 8)
I have done a little research into Emachineshop a while ago but because they were stateside and becasue they recquired the use of another piece of software I did not pursue them, but it was a pretty cool solution. You don't say if the $600 was for one or one hundred parts. If they were for say 30 wheels (I have no idea how many panzer IV wheels are needed) then that would work out to a cost of approx $20 per wheel which to be honest sounds quite good.
You do know that Armoutek are building the panzer IV again (as far as I know the only model company to do so ) for next year don't you. Perhaps emailing them now and asking if they will sell you a set of wheels or suspension components tracks etc etec. this would solve a lot of technical problems you will undoubtly face.
If you wait too long prior to approaching Armoutek they will be less likely to help you as they batch order / manufacture runs of components to suit a particular quantitiy of models that they are going to sell.
PS Aromrotek aslo sell a Panzer IV build manual, check out there website......................... Might be the answer to your prayers?
As posted in the rubber injection thread I said I would post some pics of the current warrior design.
I redesigned the sprockets a while back (2 - 3 months ago), and since doing that all hell broke loose. From going away on business, working very late hours and continuing with my evening classes, I have had hardly any time for Harry and Juds let alone the warrior. Never-mind, work is calming down next week, so normal service should be resumed.......
Sprocket re-design - quite proud of this!! 8) 8)
Real Warrior Sprocket for Comparison
This design utilises a transtorque keyless bush and steemed from the design requirement of not using a keyway on a 12mm internal bore. This was a machining limitation set by my machinist.
I did consider the use of Taper Lock bushes and I have to thank Vince and Mark for helping me out with the datasheets for that. If anyone is ever looking for the design data requirements for a taper lock bush I would be pleased to help, pdf'd and ready to send!!! These were impossible to find this info on the internet. Besides once I checked the physical size against my hub I found that it would be too big anyway. Then I stumbled upon keyless bushes, from RS, these cost @ £15 ea and are the muts nuts, slim and can transmit upto 40Nm of torque before slipping, which to be fair is impressive!!!!!!!!!!!!!!!!!!
Hope you like and can see why I'm proud of it, this is a culmination of approx a 20hrs of work between research and draughting.
At present the Sprockets gear ring will be rapid prototypes, until I get the tracks cast and marry them up with the sprockets. If all ok, I'll get the sprocket teeth machined in alloy, and the current bolts replaced with the correct bolts being inserted from the opposite side. Rapid Prototypes don't mind a thread being cut into them, but I don't think it would be wise for this application
Just had a chance to study your new design for the sprocket. A great bit of reverse engineering from the original, and spot on if you were building a strictly scale model. But would you consider omitting/reducing the rubber-tired centre spacer?
Looking at the 3D CAD, I just have the feeling that, though the full scale design supports and centres the track as it rotates round the sprocket, the miniature version with only, say, 15-20mm centre gap might clog up or trap small stones, risking throwing or breaking the track at its point of maximimum dynamic stress (ie where the drive loads from the sprocket teeth are applied).
My thinking here comes because I was initially disappointed that my M-1-T Panther lacked the cone-shaped sprocket casting of the original but having done a few test runs, I realised that while the full scale design would self-clean, a scaled down facsimile would only serve to trap and compact mud and stones behind the outer sprocket ring. My point is with working models some environmental problems do not scale down and we have to design round them.
Do other, more experienced, owners have views on this? Which vehicles are most prone to clogging? Is it better to run loose tracks to accomodate clogging and drive more slowly ( so not to throw in turns) or run tighter, faster tracks hoping stones get flicked out before reaching the sprockets?
BTW Happy Christmas, One and All!
I did actually start off with a more simplified hub, which did not have a cone within the centre point as the design stands at the moment. I commenced the re-design due to the taperlock bush problem and with idea of making it more accurate and to try and make it lighter (it was basicly a round billet of alloy, which weighed 1/2kg each they now weigh 1/4kg each)!
Now I'm thinking about it you are correct as they will provide a stone trap, whether enough to jack the track off and break who knows?
Of course the nature of this design does allow for the complete removal of the inner wheels, so it should be possible to experiment with both set-ups and see if this makes any difference, ie inner road wheels attempting to jack the track off. Also don't forget I'm playing with the idea of having the tracks under constant tension so that when the sprockets start to stall the idler will moe in to reduce/maintain the tension, hopefully stopping failure..... experimentation, don't ya love it!!!!
I think the Armourtek Tiger does have the cone feature on the hub, and after seing Vinces creation on the armortek forum he has retained this feature on his aftermarket sprockets.
Maybe some the Aromortek Lads and or anyone else who has employed the cone feature in the sprocket hub can advise if they have had any problems?
Been playing with Inventor again, trying to get the lower hull finalised so I can get the hull plates cut, the design has NUMEROUS M3 tapped holes all over the plates to take bumpstops, track carriers, suspension hub plates etc etc.
I managed to finalise the suspension lock-outs, these will be non-functional, possibily cast in brass or alloy. They are very close the trck and so will be liable to take a bit of a bashing! I know they may break, but to me they set the model off!!!!
If anyone has any experience of the Warrior, can they please advise on what the shape of the rear idler wheel tensioner is, I have at present a Non-dished design, however I am convinced it is either recessed or raised????
Have a look below and let me know what you think?!
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