yogi-bear 2321 Posted March 13 that 1/32 Hunter will be a pretty cool project, keen to see how it runs. Share this post Link to post Share on other sites
silvertriple 3557 Posted March 15 Today, a few elements arrived. I had already a mini servo sitting in my stuff (an order mistake at some point, but the data says it is powerfull enough for a car, I just way the good occasion to use it - spoiler : it won't be for this project). It is small, but not small enough for 1/32. it would work good to make a 1/20 car... I have a smaller size servo on order, not sure when it will arrive, but i'm looking forward for it... ESC and RX should not be much issue, on the other side... Saying this, in the event the micro sized servo doen't work, I can probably target a 1/20, 1/24 or 1/28 Hunter (in anycases, I'm able to print a body shell mould (and possibly a bodyshell as well - even in colors eventually), and that should not be much a problem, and would probably easier for the battery as well... 1 Share this post Link to post Share on other sites
silvertriple 3557 Posted March 16 Before moving on the target, we need to understand first if it is possible to print an universal joint in place and what tolerances are required for this. I first designed a universal joint around 1/2 of the original Hunter universal joint... Next activity is to try to print it and play around with the tolerance to see if feasible... And my 2 first tests were unsuccessful... It PLA, it doesn't help, and the print orientation neither... But we need to understand how interlocking can work before doing any optimsations... I guess I will have many 10 mins print today for this... Share this post Link to post Share on other sites
silvertriple 3557 Posted March 16 3 semi-successfull prints. It always split at the same place, and suprisingly not parallel to the printing plan, but perpendicularly to it. The reason is because of tolerances in this situation. The one side I was expecting to break easily works perfectly as soon as you have more than .15 tolerances... Basically, if we rotate the printing plan of 45° and make sure that the starting point of the cross member is supported that should work fine. I reviewed the design to add material which I intend to cut post printing. And the test print is 100% success! This means : Rear suspension is possible. I'm now thinking about scale : the optimal option seems to be 1/20 (scale 1/2 compared to the original Hunter), as screws and nuts are probably the easier to source in those dimensions, and it has the advantage of allowing for more material than lower scale. Share this post Link to post Share on other sites
silvertriple 3557 Posted March 16 The micro sized servo is arrived... It's really really really small :-) I will need to model this guy first and then think about the work to come... It may be very well suitable for a 1/32 size Hunter (without suspensions in the case I go for 1/32)... Share this post Link to post Share on other sites
silvertriple 3557 Posted March 17 To start working, we need to have the dimension right... So I put the two servos in CAD (it's a five minutes job, ad it will allow to work this out easily)... Digging in the smaller size, I need to understand a bit better about gears printing in very small module. I have the Marui gear set working in 0.8 (almost 32dp). Printing this scaled at 50% would probably give some indications of feasibility at 64dp (I may even use the Marui gearset scalled at 50% to make a 1/20 Hunter if it is workable). I put the gearset in Bambustudio, scaled it at 50% and printed it right in 0.08mm layer thickness, with tree supports and 100% infill. Here is the result (with a Super Wheelie idle gear and not a Hunter one) I used filament trimmed at the right length for the small bevel gear axis... And it seems it is viable :-). I check and it works... I may need to review some posts of one of my friend about printing gears at it might be even usefull here... Share this post Link to post Share on other sites
silvertriple 3557 Posted March 21 I printed a roll cage for testing purpose... The result is better than what I expected (again, no specific support material, just printed it in PLA). I may need to print the remaining parts as well, so I have the full set of parts to show... And I ordered the print online for the project car. - Hunter proto chassis in black, without switch holder - MJF PA12 black - gear covers in both 380 and 540 versions - MJF PA12 Black - roll cage and radio lid - MJF PA12 black - arms and bumpers, and under gear cover - SLS PA12 White (idea is to get those dyed in light color) - gear sets (MJF PA12 Black for the diff, Stainless Steel SLM for the idle gears) - and a Mitsubishi Jeep bodyshell in resin as I need to understand if it is feasible or not in resin (it's basically too big for my printer) Arrivals are expected to be by 2 weeks from now... Share this post Link to post Share on other sites
silvertriple 3557 Posted March 22 The Hunter 1/10 project is awaiting the prints from the provider to be done... Time to work on the half size target. I found some universal joints on amazon which may be able to do exactly what is required (search terms : universal joint 1/28 rc, and then I focus to find a 3mm to 3mm. Found 2 different type of dimensions, and the short ones are actually almost 1/2 size of the real Hunter joint). https://amzn.eu/d/a6MyICK That should make the job. I also ordered some brass rods in 3mm diameter length 100mm. This should be easy to work with using rudimentary tools... Last I started the real thing. Took Fusion 360 and included a derived Hunter chassis which I scaled down to 1/2 of the original chassis. I then started to pull the servos in to see what it would take in terms of adaptations... The first conclusion is that unless we cut the servo or enlarge the chassis, the Mini sized servo won't work. And then the conclusion is that we will have to work with the micro sized servo... For the Motor, after some search, I identified a Mini28 combo with a motor which is more or less 1/2 the size of a 540 motor, and that would do the job. I'll have to order one later on. I also received a sub micro linear servo, which is very small and could do the job for the 1/32 sized hunter... Share this post Link to post Share on other sites
silvertriple 3557 Posted March 24 I may have gone a bit too far regarding Hunter parts testing... Even though I ordered powder based process prints, this is not at loss : The idea is really to show that FDM printing is possible and it will allow me to show how the final result is different in the cults3D publication of the parts... Further, those FDM printed will serve also as showcase and will replace a current set of parts exposed in my usual hobby shop. Share this post Link to post Share on other sites
silvertriple 3557 Posted March 29 Not much done on the Hunter side those days. I'm awaiting the printed parts and they should come to my door within next week. The rest was about searching hardware and solutions for the reduction. I've not started to adapt the 1/2 size chassis, but I'm close to start this. This morning, however, I made a mould CAD model for the Hunter bodyshell. This will be used only for the half size Hunter. I've deliberately not marked the motor cut as I'll need to adapt this to the targeted motor. Once the bodyshell surfaces are done, pulling a mold from it is easy : it's just additional work. The target is to print this scaled 50% and work it out from there... The wing mold was done quite a long time ago, and was probably the first time I did while starting on the bodyshell components... Share this post Link to post Share on other sites
silvertriple 3557 Posted April 2 The printed parts arrived today... There is everything to build the Hunter prototype, except the wing I Intend to print in TPU... Black parts are MJF, White SLS, grey SLM Stainless Steel The chassis is black, like the roll cage (which I will probably paint but not sure which color yet) The motor covers are in both 380 et 540 versions... And the gear cover are in multiple parts (the second base is on the chassis with the roll cage) The white parts on the first picture are going to be dyed in a clear color which is still to be defined, and the gear sets are not a novelty... Share this post Link to post Share on other sites
