Beginner XX questions

[LosiXXkid]

Looks like you've got the basis for a great car there.

Some parts are getting hard to find though, in particular the front bulkhead (LOSA1101) There have been two ebay auctions over the last few months for nip bulkheads, the first went for just over £50 and the second for £48. Even a secondhand one went for £24 recently! If you have a few spare ones then great but if not I would start looking for replacements now, as they are fragile. The later white versions are much better but equally elusive and the alloy versions are almost impossible to find. Also, if you do enough research you'll find posts online advising to look for the duratrax evader version. These are not direct replacements and require a lot of work to fit, you'll also need the shock tower as well which needs to be modified and the chassis brace won't fit either. You could use tie rods instead of the brace but by the time you've done all that you've effectively got the front end off a different car. Another option would be to buy another xx and use it for spares.

Anyway, don't be put off and good luck. Would be great to see some photos of it racing, the track you mentioned should be perfect for the xx.

Sascha

Yes......the hard-to-find Losi A-1101 XX Bulkhead.....I watched both those auctions recently on eBay with surprise at the final selling price.

I might have to look at getting some CNC machined, as opposed to being injection molded, using an original as a template. I'm sure there's a company out there that can scan the original into CAD and then produce a small batch.

I would think that there is enough demand considering the recent eBay 'prices'. A bit of research is required me thinks.....

[Sascha3741]

Yes......the hard-to-find Losi A-1101 XX Bulkhead.....I watched both those auctions recently on eBay with surprise at the final selling price.

I might have to look at getting some CNC machined, as opposed to being injection molded, using an original as a template. I'm sure there's a company out there that can scan the original into CAD and then produce a small batch.

I would think that there is enough demand considering the recent eBay 'prices'. A bit of research is required me thinks.....

That's a brilliant plan.

I'll take at least one of them. According to Valkyrie Motorsports the ebay seller based in the USA, the brass or alloy bulkheads sell second hand for well over $100. At today's exchange rates $100 = £65.16, so hopefully a small batch should come in well under that figure per item. Also, Losi have no plans to re-manufacture the bulkhead, so it would enable a lot of people to continue racing the xx.

Good luck and let us know how you get on.

Sascha

[mytimac]

As someone who has looked into making new A1101 I am sure the CNC route is cheaper. But long term i think it is a terrible idea. I ruled it out because now you are just going to break other stuff that is just as hard to find. If it is for a dust collector than i guess it would be no big deal. But if you plan on running the thing...

I am currently designing a new a1101 that is cheaper to make and easier to replace when broken.

[Sascha3741]

As someone who has looked into making new A1101 I am sure the CNC route is cheaper. But long term i think it is a terrible idea. I ruled it out because now you are just going to break other stuff that is just as hard to find. If it is for a dust collector than i guess it would be no big deal. But if you plan on running the thing...

I am currently designing a new a1101 that is cheaper to make and easier to replace when broken.

Brilliant, thanks for letting us know.

I see your point about a CNC bulkhead transferring all the forces to other parts of the car. I'm assuming that the front arms, chassis and chassis brace would suffer more.

Would be great to see a viable alternative to the original part. Please keep us up to date with any progress.

Sascha

[kjrell]

Interesting idea, what about machining a softer material like Delrin?

[LosiXXkid]

So far I've e-mailed two company's for a quote......so far no replies......

The CNC machining route has to be the most financially viable option IMO, it's way cheaper than injection molding and the turn-around time is relatively quick. The CNC method also means that the bulkhead can be machined from whatever material is chosen. Delrin is one option:

"Delrin® acetal homopolymer bridges the gap between metals and ordinary plastics with a unique combination of creep resistance, strength, stiffness, hardness, dimensional stability, toughness, fatigue resistance, solvent and fuel resistance, abrasion resistance, low wear and low friction."

The above quote is from the DuPont website (hope this is OK) and might indicate that Delrin could be too 'tough' for the application if it's use would cause other front end components, such as A-arms, chassis or the chassis brace, to fail instead.

Nylon is the other suitable alternative that can be successfully machined.

Anyway, I'm hoping to receive a response from one of the companies I've contacted. If not, there are a few more companies that I've found that offer the 1-off and small, low volume/prototype service.

[Sascha3741]

Wow, I think it's great that there are guys out there trying to solve the xx bulkhead problem.

Since my last post, I sent an email to horizonhobby.com (TLR's website refers product queries to them for some reason) asking if they would consider reproducing the item in question or to provide CAD drawings/blueprints to help us out. I got a response simply stating that the bulkhead is no longer in production and that there were no alternatives. They did point me in the direction of an ebay auction for a used one though, which I've listed below:

http://www.ebay.co.uk/itm/190825798774?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649#ht_203wt_1141

Hope that helps someone who needs a replacement.

[LosiXXkid]

Had a reply today from one of the company's that I contacted with regard to manufacturing the A-1101 XX front bulkhead. They have verbally quoted me the costs and this little project is definitely looking viable.

They will need drawings which I may have to investigate and source separately but material costs (e.g. nylon) will be about £1.00 per bulkhead and around £8 or so for the machining time. There may be a 1-off set-up cost but this wasn't mentioned.

I will also consult them on the best material to use for application as I'm fully aware that it can't be too soft nor can it be too hard either.

Will update when I have more information.

[kjrell]

Did you got any news?

I've read somewhere (cant remember where, stupidly forgived to bookmark link or failed to do it ) that Dupont Zytel is the most common nylon used in rc applications

Dunno if it is the right one for this particular application anyway....

Here is the link about it:
http://www2.dupont.com/Plastics/en_US/Products/Zytel/index.html

Hope it helps!

[LosiXXkid]

Interesting.....although it would appear (to me, but I could be wrong) that DuPont Zytel is a resin which would imply that it is used in injection molding. If it is available as a solid that can be machined then I will make the request.

I need to get the letter with my sample bulkhead sent off (been busy with other things as usual) and should get it done this week. I will post an update as soon as I know more but this has not been forgotten!

I'm on it.....

[minreg]

I broke a Trinity xx4 front bulkhead the first time out. Since then always been leery of aluminum bulkheads.
That is just my experience, maybe a fluke but just putting it out there. Wonder if others had similar experience with aluminum front or rear bulkheads.

Either way I would be happy to have any type or style 1101.

[LosiXXkid]

I am hoping that I can get this turned round pretty quickly but initially I will need to get my hands on a couple of prototype bulkheads for evaluation. Once the drawings are done this shouldn't take too long but the cost of the getting the drawings done will certainly be a factor.....

[jamin]

What about 3D printing - surely its an excellent candidate?

[jamin]

I broke a Trinity xx4 front bulkhead the first time out. Since then always been leery of aluminum bulkheads.
That is just my experience, maybe a fluke but just putting it out there. Wonder if others had similar experience with aluminum front or rear bulkheads.

Normally the ally bulkheads would break the chassis, a much more expensive way to crash, those bulkheads should only really be for show.

[jwscab]

you will want them out of nylon 6/6 or delrin. the nylon is probably cheaper and most likely a bit 'stronger' as it 'chips' less than delrin does. if you get it in white, you can also dye it

the other thing is you can make it cheaper by making your prototype/drawings have less features. It certainly doesn't need to be hollowed out underneath, this saves a ton of machining time and setup. think of it as a simple 'block' construction and it will be cheaper AND stronger.