S550 Carbon Doors Project - from the depths of Badger Labs

[honeybadger]

So for the last couple years I've been dreaming of a carbon door solution for the S550 chassis. And I mean a real race car carbon door - with integrated window frame so you can have a removable lexan window and a functional, but finished door card. I've seen the likes from Anderson, but they're just a carbon copy (pun intended) of the OEM door - which is disappointing for $3k. The GT4 doors of course are supposedly available, but I've been told they're $4k each. I can ruin a lot of carbon and burn a lot of CPU threads for $8k.

So here we are. This will probably turn out terribly, but I've taken on bigger (and stupider projects). let's see where it leads us.

So looking carbon doors - I have two ideas I'm juggling. First, is the GT4 carbon door. Sexy - but there's a decent amount of space inside that door cavity that could be utilized. Some folks have cages that stick out and or you're like me and have your brake/clutch reservoirs there on the drive side and radio on the passenger.



So that let me to look further and find this - a 996 GT3 Cup car door. the pocket gives space for the cage/extras. Leaning this way at the moment




I've started playing around a bit in Fusion based on my scans. I'll never claim to be more than a monkey with access to a keyboard and mouse in CAD, so I am going to heavily favor function over form.
First, here's a very rough draft of the interior side



And i've started modeling the frame for the window -



Some assumptions:

1. I will not be using OEM mirrors, interior opener lever, or hinges.
2. Will 3d print my mods, glue them to OEM doors, do some finishing (paint, bondo, etc.) and then make tooling moulds
3. needs to have a service door for the oem door latch mechanism (similar to the porsche doors)

Would love ya'lls feedback on design, any quality of life recs, and anything I might be missing (outside of my sanity - that's long gone).

 

[GAR944]

Absolutely love where you are going with this.

As another who plays with 2d cad all day, 3d design does my head in. I haven't got my brain thinking in the right process path.
Anyway, you wanted feedback. Your initial design looks very similar to a Porsche design, unfortunately its from about 1978, a 924 Carrera GTS.

In terms of manufacturing and strength, a less angular loft into the cavity will allow you to drape a full sheet into the cavity rather than doing multiple pieces. As per the latest Porsche doors you showed.
See, i couldn't give you a 3d version but you get the idea. Closing Fusion for another month again.

It will also mean removal from the mold will be way easier.
From my deep dive into this topic many many years ago, apparently the hardest part is getting the window frame section not to spring out after removal from the mold. I believe they were even adjusting the mold to compensate for a certain level of spring back.
There was also some discussions about specific directional layout of the material that would stiffen the structure. If come across it again i'll link it for you.
The other decision is material. Have you thought of using carbon/kevlar weave, especially for the outer panel. Less likely to fracture on impacts, not that you are going to have those but general hits, drops in the workshop.
Quick release door pins should be on your quality of life list. Being able to pull a Cup Car door off in a few seconds and put it on the shelf is awesome. Especially when trying to work over door bars in a tight shop. You did mention you weren't going to use the oem ones.

 

[mwjscn]

Coming from my DIY vacuum forming experience, I would agree that some draft angle on the pocket walls and larger, softer, fillet angles on the inset door pocket edge would make your life easier when it comes to layup and mold separation.

 

[Stan Whitney]

If you have not already, you will want to make the door hinges pinned for quick removal. Makes trailer loading, maintenance etc easier. Most gt* doors are. I'd consider moving components inside the cage/tub just for crash survivability. You may need the radio or brakes to still work after an impact.

 

[honeybadger]

Absolutely love where you are going with this.

As another who plays with 2d cad all day, 3d design does my head in. I haven't got my brain thinking in the right process path.
Anyway, you wanted feedback. Your initial design looks very similar to a Porsche design, unfortunately its from about 1978, a 924 Carrera GTS.
View attachment 111127
In terms of manufacturing and strength, a less angular loft into the cavity will allow you to drape a full sheet into the cavity rather than doing multiple pieces. As per the latest Porsche doors you showed.
See, i couldn't give you a 3d version but you get the idea. Closing Fusion for another month again.
View attachment 111126
It will also mean removal from the mold will be way easier.
From my deep dive into this topic many many years ago, apparently the hardest part is getting the window frame section not to spring out after removal from the mold. I believe they were even adjusting the mold to compensate for a certain level of spring back.
There was also some discussions about specific directional layout of the material that would stiffen the structure. If come across it again i'll link it for you.
The other decision is material. Have you thought of using carbon/kevlar weave, especially for the outer panel. Less likely to fracture on impacts, not that you are going to have those but general hits, drops in the workshop.
Quick release door pins should be on your quality of life list. Being able to pull a Cup Car door off in a few seconds and put it on the shelf is awesome. Especially when trying to work over door bars in a tight shop. You did mention you weren't going to use the oem ones.

That's a good catch on the draft angles. I haven't done enough composite work yet to have any frame of reference for something this complex - i'm now wondering if I need to make the entire "interior shelf" part removable and make it a separate mould. ALT, I could soften the angles and then just acknowledge it'll take a few different pieces of fabric to make it work. Hmmm

I have been looking at carbon kevlar for the outer skin. I've busted a few carbon parts now and it really sucks when they crack from impact

And 1000% on the quick release. forgot to put it in the original post, but that's probably the second biggest reason. I take my doors off now to work on the car and my gutted doors are still like 30lbs.

Coming from my DIY vacuum forming experience, I would agree that some draft angle on the pocket walls and larger, softer, fillet angles on the inset door pocket edge would make your life easier when it comes to layup and mold separation.

agreed. will work on a v2

If you have not already, you will want to make the door hinges pinned for quick removal. Makes trailer loading, maintenance etc easier. Most gt* doors are. I'd consider moving components inside the cage/tub just for crash survivability. You may need the radio or brakes to still work after an impact.

100%. I want to design something that can use these for easy removal

 

[honeybadger]

okay - v2

Wonder if I went too big?

 

[GAR944]

I like V2 much better. However, sound like a bastard here, i think the lower edge angle needs to be maintained all the way round. Have a look at the Porsche doors and follow the weave pattern and the soft shapes they use.
Grab some thin fabric and drape it over a clothes basket and see how it hangs and how far you can push it before it puckers and needs pleats. That's what i would suggest you are trying to avoid in the design.
There is a lot of information in those photos of how much they can do as a continuous sheet of material by keeping all the curve transitions as soft as possible.
When you think you are close you could 3d print the corners and put a cardboard piece between them over the top and drape the final material to see what it will do first. Will keep from you eating into that $8k budget

 

[honeybadger]

Took another spin at it. I think I like the previous design better, but probably need to print it to know for sure.

I'm thinking of adding a spot for the pull rope to locate it, but need to think about where I want the pull handle vs opener

 

[GAR944]

Ahh the joys of design. Functionality vs Aesthetics vs Manufacturing.
Whatever you end up with be amazing. Have faith in your ability given your track record.
Thanks for bringing us all along for the ride.

 

[Randomtask]

@honeybadger take my money!! I’ve been running some carbon doors for a while and I’ve been eyeing up making a finish panel for them. I’ve just never gotten around to it. Now some lexan Motorsport windows would be soo good!!!

I’ve seen @Ring_Mach1 made himself some finish panels.

I’ve looked at my doors and save from that one bump in the door that sticks out, there’s a fairly flat surface to mount a panel.

I’ve currently got my cable door pull set up with a TPU handle.

IIrc there was a company producing a door that had a finished interior, and it had no exterior door handle.

https://paulsautomotiveengineering.com/products/autoclave-prepreg-carbon-fiber-s550-mustang-door-skins?srsltid=AfmBOor-RoZgArNSq2XO4ISWQLKnpi3BCXO4NwTfx5Jjjx4H7o6xJ5XF

EDIT, it was MMR that had a door with no handle. I never got them to confirm what the interior looked like:

2015-2023 Mustang S550 GT / GT350 / GT500 Carbon Fiber Doors [427238] - $3,303.99 : Modular Motorsports, Home of the worlds fastest Fords

Modular Motorsports 2015-2023 Mustang S550 GT / GT350 / GT500 Carbon Fiber Doors [427238] - These Ultralight Carbon Fiber composite doors for your 2015-2023 Mustang Ecoboost / GT / GT350 / GT500 are designed for Drag racing, Road Racing, HPDE, Time Trials Etc . All factory hardware bolts right...

www.modularmotorsportsracing.com

 

[honeybadger]

made some progress on my window frame tonight. however, because im a dunce, I scanned two different doors. so I need to re-scan the passenger door tomorrow and then transfer my door card over so I can align the meshes and properly joined these two pieces.

 

[dragoon]

I like where you’re going with this Kevin. Again, your pay grade is diffidently well above mine for sure. HB is going to be kick ass !!
GO LIKE HELL

 

[ArizonaBOSS]

That's a good catch on the draft angles. I haven't done enough composite work yet to have any frame of reference for something this complex - i'm now wondering if I need to make the entire "interior shelf" part removable and make it a separate mould. ALT, I could soften the angles and then just acknowledge it'll take a few different pieces of fabric to make it work. Hmmm

I have been looking at carbon kevlar for the outer skin. I've busted a few carbon parts now and it really sucks when they crack from impact

And 1000% on the quick release. forgot to put it in the original post, but that's probably the second biggest reason. I take my doors off now to work on the car and my gutted doors are still like 30lbs.

agreed. will work on a v2



100%. I want to design something that can use these for easy removal View attachment 111129

Hey Kev--consider using D-shape or "Square" shape clips for the door hinges. You can get them in the same pin diameters. On the S197 I think the pin diameter is (or is very close) to 5/16". I initially went with the pushbutton ones like you have above, but these were difficult to both press/hold the button and pull the pin out of the hinge holes, considering the tight space where the hinge resides. FWIW I put the upper hinge pin in from below, and the lower hinge pin in from above.

 

[mavisky]

I know that the RTR drift cars have been running kevlar bodies the last few years. May be able to talk to them about skins. They went with kevlar over carbon for the flexibility and repairability after vehicle to vehicle impact.

 

[blacksheep-1]

I like V2 much better. However, sound like a bastard here, i think the lower edge angle needs to be maintained all the way round. Have a look at the Porsche doors and follow the weave pattern and the soft shapes they use.
Grab some thin fabric and drape it over a clothes basket and see how it hangs and how far you can push it before it puckers and needs pleats. That's what i would suggest you are trying to avoid in the design.
There is a lot of information in those photos of how much they can do as a continuous sheet of material by keeping all the curve transitions as soft as possible.
When you think you are close you could 3d print the corners and put a cardboard piece between them over the top and drape the final material to see what it will do first. Will keep from you eating into that $8k budget

View attachment 111132

I would disagree with that, while using the same curves is esthetically pleasing, I don't think I've ever seen a cage that had the same angles front and back, they usually come into the door cavity on an angle from the front A post bar. I would make those cavities as huge as possible and maybe even run a layer of Kevlar between the door skin and the inner door cavity.

 

[Randomtask]

Might be worth a poke around at COTA for the WEC race in September to get eyes on how all those different manufacturers are doing it.

 

[honeybadger]

Might be worth a poke around at COTA for the WEC race in September to get eyes on how all those different manufacturers are doing it.

unfortunately WEC is as bad as F1 - everything is blocked off. Not just with ropes - but like walls and stuff. Went last year and I was really disappointed. Fortunately World Challenge is doing an endurance race next May, so I'll get my GT3 car fix then.

IMSA is so much better than, WEC, imho. way more accessible - just needs more GTP cars!

 

[Randomtask]

w

unfortunately WEC is as bad as F1 - everything is blocked off. Not just with ropes - but like walls and stuff. Went last year and I was really disappointed. Fortunately World Challenge is doing an endurance race next May, so I'll get my GT3 car fix then.

IMSA is so much better than, WEC, imho. way more accessible - just needs more GTP cars!

I went to the GTWC America race there earlier in this year and it was great. Full access. Talked to the mechanics, scoped out the cars. Grid walk etc.

I guess the GTWC proper gets a bit more fancy!