cgrcjet

Pylons!

After i machined all the pylons i decided to machine the little bolts and then decided to go ahead and machine the panel lines while they were still in the block. This got rid of the scribing nightmare as this detail would be very hard to do. It took a little time but i think it was worth it. I even went as far as putting the star pattern bolt head. I will add the raised paneling and rivets to these later down the line.

chris


Pictures uploaded but still not working right. I guess i will post them later again.

cgrcjet

Finally got some pics to post.


chris

cgrcjet

Bottom wings.

invertmast

My Feedback: (23)

Chris you are really out doing yourself! I got your message, i'll give you a buzz tomorrow around noon

cgrcjet

Sounds good Thomas. Heres the beginning phase of the tires. I plan on doing them molded hollow as Tams solid ones were nice but a bit heavy. The robarts would shred off after a few flights. Wall thickness on these will be between 2 to 3 times thicker than robart .I think it will be very simple to mold these. I machined this with a .0197 bit but i will need to go even smaller for the size of the lettering on the side walls. I ordered .01 and .008 end mills today and i think that should do the trick. These are crazy small end mills. Just thought i would ask to see what you used.

thanks
chris

invertmast

My Feedback: (23)

All the tires I have done have been solid and very robust. But like you say, they do get a bit heavy. If you do a hollow core tire, you'll probably need to do a 4 piece mold. You will need the outer halves of the tire, and then a 2 part inner "donut" that is cut in half width-wise that can be screwed to the outer halves of the tire mold. You should then be able to pour the tire, leave the material to cure till its thixotropic and then remove the donut halves and clamp the outer tire mold halves together till fully cured.

The other way I think would work, would be to get some closed cell foam and cut donuts from this that would need to hover inside the tire mold half, that is undersized to allow for the rubber wall thickness, then pour the tire, leave to partially cure and then clamp each mold half with the foam 1/2 donut still in place.

Whatever you use for the mold (especially for the lettering and tread halves) will need to be extremely tough to not wear out prematurely and handle the clamping pressure (i used a 4" C-clamp)..

We can talk more tomorrow, its a different process to go about, i'll even do your tires for ya if you supply the molds and materials

cgrcjet

My idea is pretty simple. It will be a stack of moldings and plates that will have alignment holes for pins. The tread pattern is very simple on the a-10 and the plates will act as the tread detail. The plates will be in 2 pieces so they can be pulled apart when demolding if needed. There will be a silicone plug made for the inner void that can be pulled out after demolding. I think this will work good with the right deromiter silicone. Here is an inner side view.


chris

john534

Jeez Chris, I thought you were putting some detail in this thing ...and put some damn rivets in it! LOL!

Just kiddin!

Your detail is looking out standing and the tires will be sweet!!
Give me a call when you can this weekend...

John

wojtek

My Feedback: (73)

awesome awesome awesome work Chris !!


what is the foam are you using for CNC routing ? I like the results you get, and looks like you pour it into your forms ? what bits are you using on it ? im guessing ball with a tight stopover ?


all best,

Voy

cgrcjet

Hey John. I will put some rivets on the tires for you while im at it. Sorry i didnt call back. We were over at a friends house.

Your going to be able to machine these rims in your sleep compared to your p51! Now we just need to push Tam on his new electric brakes so we can get these finished up.

Give you a call tomorrow.

chris

cgrcjet

Hi Voy

Thanks. Its actually casting resin that i pour into the forms. I just cut the inner form out, a bit over 1/4" past the part extends to save on material. The wood part is for screwing to the table. For the forms on the pylons, even though they were different sizes, i cut them the same so i could use the same template on the work surface to flip the parts for 3d machining. I usually use one form and re cast resin but i was unsure the extent i was going to machine on these , so i made separate forms. The forms were clamped to polyethylene when casted as it will not stick to it.

I used a 1/4" bit for roughing and a 1/8" bit for finish on the bodies. Finish pass was .008 stepover. Both end mills. No ball ends. For bolt detail and panel lines, i used .0197 bit. They have a very good finish on them. There are a few small spots i will need to hit with 320 but for the most part, i can start out with 600 grit and go up from there.

thanks
chris

sam@ata

My Feedback: (16)

I must say Chris, the detail and effort you are putting in to this will put some plastic models to shame. I enjoy reading and seeing the progress to date and wish I had a fraction of the patience and desire you show. Great job by far.
I have flown my WOWPlanes and am trying to work with Robart on new gear. The Eflites aren't up to the task as expected but at that time not many options of electrics. Once I get the gear replaced then I will continue on to finish it out.
The canopy and hinges have worked out great. I am glad to suggest to other builders, these mods to the original kit and the ease at which the flaps can operate. Well worth the extra time and effort. Thank you!
Keep up the great work and hope all is well in the sunny state!!
Sam

wojtek

My Feedback: (73)

Chris, I will have to try that .. I have been mostly machining in either foam or wax ( wax for the smaller stuff like instruments and the like ) thanks for the tip/suggestion !


.008 stepover sure explaing how smooth it comes out ! on my router that would take for ever .. its slow on the Z ...


again, very nice work !



~V~

cgrcjet

Thanks Sam. Im glad everything worked out for you. Well i guess except for the gear. I talked to Tam the other day and he says he will be coming out with some electric gear and brakes. I think hes finishing the designing now. He said he was going to fit them up on the A-10 i will be sending him for testing. I hope its soon because im tired of re designing stuff for this thing. I think an all electric setup would be good. I need to see how the electric brakes will fit up to the new rims and make the adjustment. Maybe he will have something that will fit up on yours.

chris

cgrcjet

No problem.


The casting resin i use is a harder casting resin but it still cuts easy and smooth. There is more shrinkage than the softer casting resins, but you can let it sit for a day and let it finish up its shrinking business before you have a go at it. Mainly larger pieces. It sets up in about 5 min. Also, if you are doing a larger piece, you may want to plane down the back side on your cnc to get rid of the surface tension. Thats only if you are machining one side. With the pylons, i machined them in 3d, so i didnt have to worry about it. If you dont do this, sometimes the part can warp on you. I think this goes for all plastics as my sheets of polyethylene will warp as well if i machine one side over a larger area.

My old router cut at 120 ipm. My new one cuts at almost 800 ipm and its very solid. For each side of pylons with roughing and finish, it was around 30-40 min. Not to bad. I was dreading doing these because there are so many, but it went pretty fast this time around. The z is always slower in cutting 3d. You can also try kicking up your feedrate on your cam before you create your g code. Hopefully your machine can handle it and not miss any steps. What are you using for post processing?

chris

wojtek

My Feedback: (73)

I'm using Visual mill ( Rhinocam ) out to Mach 3 . I know i can tweak my settings in Manch3 for better speeds and acceleration, and eventually it will be either better steppers, or just might need a larger/faster machine/controller setup. I don't need much more than small items now. Im working on some control panel items, and its pretty much like making jewelery, lol some of the bits I use are as small as .01" .. Can be a pain zeroing those out when working on tiny pieces and having to do tool changes . I have started designing more in CAM now, and working around the tools, and not tooling around the project. it saves some time and unnecessary finishing cuts.

i cant wait to see your A-10 all done! must be the best feeling scratch building a project with this detail from the ground up![8D]



Wojtek

cgrcjet

Im sure Rhinocam works good. I definately like the CAD. Its very versitile. I was going to try the rhinocam but i have learned so many different softwares that i dont really have the time for a new one. I will probably get it in the future. There should be a feedrate that you can adjust in there to get your machine to run a bit faster. For along time, i didnt know about adjusting that feedrate and just adjusted the speed in mach 3. But if your machine cannot handle it then only thing to do is get a better setup. I would push my old cnc to the limit and would start missing steps. It would take 40 minutes for my old machine to cut out one wing structure. My new machine takes 10 minutes. When i moved to Florida, i outsourced and had them laser cut. I believe he had like a 45 watt laser and it would take 20 minutes on that. I also had to sand all the burnt edges off. I was going to buy a laser but after that and seeing how fast my new machine cuts, i can do without. I guess if you are doing small pieces then its not to big of a deal.

Is your site going to be up tomorrow? Maybe u can make some guages for the A-10. From what it looks like, you do some pretty scale pieces. Do those guages actually work?

Doing projects like this, the best feeling is when you start and then when your done. Many long depressing hours of impatientcy. I thought i could knock this out quicker with my new machine. Most of the time involved is research and detail. Does not take long to machine parts now.

chris

wojtek

My Feedback: (73)

Hey Chris,

Im sure you know very well, the whole CNC / CAD / CAM thing becomes a whole hobby in itself , and i can see dropping some serious $ on that stuff! ! lol ... Im good with the machine I have now, and the frame is very good, so as long as i dont need to make bigger projects it will last me a while. I had steps skipping on my machine, but it was grounding issue with the parallel port, but i resolved this. I may update the controlled and steppers if anything. We are also setting up a laser cutter. Its a 100W unit and this allows us to cut a lot of materials at a reasonable feed. It will mostly be used to cut out cockpit panel components, and will be great for layered pieces and component overlays like the full scale. For custom work it will be nice to digitally size, arrange and just "print" .

We are also now the rep/reseller for a RC 3d Printing company 3D Scale. For now its mostly very very detailed helicopter components, however I hope we can start getting some items for the jets made this way. Its not the cheapest, but it can't be beat with casting. There is a picture of some parts on our new site now. The stuff 3DS makes is incredible ... it should be, as its made on the same equipment that medical implants and parts are printed on, lol .. there are other products you will see listed soon also that have to to with scale accessorizing.

Our MFDs and HUD do work. Before the new site is fully up, check out www.voy-tech.com . We do actually have some a10 specific content for the FLIR and nav menus. Alex from Little Jet Company has some pictures and video also of our new HUD on the F-104 build thread he did on Ali's jet. .. this would be too large for your size A10 however unfortunately.


I know what you mean about the research and detail ... the actual work usually ends up being the fast part


Wojtek

Dimuth Tharaka

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cgrcjet

I thought i would just use the old molds for some of the smaller items but seeings this is a super scale A-10 i decided to redo them. I have much more experience now and went about it in a different way. The molds are a one piece with a cap and hole so i can insert some all thread as its curing. Also gets rid of the flashing as you can see on the older parts. I can say the old ones were cheezy and the new are much easier to deal with and have nice crisp detail. Old and new wingtip light. Much more scale.

chris

cgrcjet

My new tire. I have the rubber material but cast this out of urethane to get a faster result. I think im going to have to invest in a degassing chamber for these.

chris

invertmast

My Feedback: (23)

Guys,
I stopped by Chris' last week to check out the A10, and this thing is just amazing! The detail on everything left me absolutely speachless. This will be, by far, the nicest A10 and i cant wait to get my hands on one!


Chris,
The tire looks good. When you go to pour them, dont let the stream out of the mixing cup get larger than 1/8-3/16" in diameter, and dont move it around the mold, it has to stay in the same general spot where it first touched the mold or you will get massive air bubbles on the surface.

McsGuy

My Feedback: (1)

Thanks for the update, I was already excited with anticipation. Now I can't stand it . I've already purchased 2 of Stumax's new 110mm EDF's for it. I have one in a Spark and they are amazing in performance and turbine like sound. I was going to use a couple of his original pushers which also perform and sound exceptional but opted for the added speed and power.

cgrcjet

Thanks for the kind words Thomas. And thanks for stopping by with the cloth.

I received all the samples they had and I purchased the 70 shore rubber that was the other product line than what you purchased for the tires. Its slightly but not much harder than the robarts material. It has a very good tear rating compared to the other materials and by making the wall thickness slightly thicker, I think they will work out great. I think I will make my own chamber just to be safe seeings this will be a hollow tire. I usually try and pour it like that but don't always have the best of luck.

Unfortunately I had to make an emergency flight to California today to save my daughter from her mom. Hoping to make this quick and get back home with her.

And thanks joe. Thanks for sticking through on my trials on this one. Sorry for the wait guys.

chris

J.F

Hey Chris,

How's things? Have you managed to get any more done on the A10?

J