Suspension mounts in Tony P's book...

[RaceMag]

along these lines:

[The DOA]

In my mind I would prefer to see 2 bolts at the inner mounts rather than the single ones you have shown , purely to stop rotation of the mounts (vibration is a strange thing and theres lots of vibration in a racecar) but I see your logic. The problem I would see in your arrangement is making sure the face that the brackets mounted to was flat enough to ensure good clamping load for the inboard brackets.

An alternative would be to rotate the rod ends by 90 degrees and use a series of holes in a simple folded bracket, welded to the chassis with the slot oriented vertically at the chassis end.

[RaceMag]

The plan was for one bolt and a pin in the slot will stop rotation. Otherwise two bolts top and bottom of the bearing plate would also work, but would require a longer slot - though they could be much smaller diameter too.
Re making them, I am fortunate enough to have some access to a friend with a large CNC machine and laser cutter.
What I see as an advantage for us: the bearings can be broached into place, thus the mount requires no steps or circlips. The wishbone ends will be simpler to manufacture. The actual mount pint will be stiffer in bending at the mount point...not really an advantage, but it just crossed my mind earlier.
I did forget to show the anti-intrusion bar at the base of the A arm but I was rushed a bit.

[The DOA]

I see the point in doing it but..

I have seen slots on racecars to adjust the height of wishbones and I dont like it one bit. My reasons for this are:

1: Slots allow movement without a secondary retaining method (ie vertical adjustment screws) partiularly in areas of high vibration which solid mounted engines are prone to creating. This is not an observation made from working on racecars, but one made while designing paper processing machinery drive adjusters amongst other adjustable features using slots.
2: How do you adjust up and down accurately? Without adjustment screws it is a PITA to adjust anything in a slot, particularly if it is prone to rotating as you do it and you dont have a genuinely flat face to mount to. If your commited to the idea, might a series of holes be a better approach than a slot?

Further things to think of IMO and in no particular order are:

1: You will definately be making the job heavier with this design. The design you have shown for the inboard chassis mounts would, I presume, would be steel with the stud welded in place? Another worry if you are welding is the affect of the welding process and potential failure in the heat affected zone of the weld if on the mounting face side. This might be better as an Ali block with a stud pinned in position. Similarly, you are adding steel to the inboard wishbone pivots which again is heavy.
2: The weakest link in the system is the outboard pivot bolt which I am presuming is in double shear from your upright pictures so will be pretty strong. This could very easily lead to quite a lot of extra damage beyond the wishbone should you have a crash (perish the thought).
3: Once installed, there is no fine tuning of the castor angle and trail available which you could get with rod ends at the inboard end top and bottom.
4: You are adding a lot of work to the job doing it this way and making the inboard wishbone ends will be much more complicated than a simple threaded tube end insert as would be used with a rod end. To my mind this part requires both a turning and a milling operation wheras a turned tube insert is a simple turning excercise. For a simple DIY project this doesnt sit well in my head.
5: I cant quite visualise how you will make a slot for the chassis mount studs to move up and down in without a lot of faffy and unecessary fab work. I think you might have shown this as a machined and slotted component that is then welded to the tube so maybe this isnt fab work but thats a lot of wastage and expensive machining time for other DIY builders without your facilities? Could I suggest that if you go this route, you use a similar design but instead of having a single slot, you drill this insert at a number of positions and fine tune the position in the final manufacturing stages to ensure the pickup points are at the correct height? This approach would allow you to predict the roll centre locations/ride height adjustments you could get from this arrangement rather than randomly moving things around.
6: The idea of using the sphericals with a staking tool is definately the way forward (lighter, simpler and I have found you cant get a circlip into and out of the housing when using small diameter sphericals). However, this requires a bit of testing (to destruction probably) and a hydraulic press and formed staking tool in order to stake the bearings in place. I mention this only because its a bit of a faff for a DIY builder but would personally use it anyway at the outboard end lol.

Sorry if I sound negative, Im hoping my apparent criticism comes across the right way and am genuinely trying to be helpful. I do like some of the elements of the design. ie You can get the wishbone inner pivots into the correct position with shims and height adjustment with relative ease, its just making sure they stay there and the complexity of the manufacture that worries me.

Anyway, some food for thought perhaps .

On a slightly seperate subject, are the hubs you are using at the rear production items? If so would you mind sharing what car they come from and what driveshaft ends you are using? I am in the process of desinging my own car myself and will be looking into this sort of thing at some time in the near future. Also, do you guys have any decent bike engine models that you would be willing to share? I have reasonable models of a 2004 R1 and Hayabusa engines from Palatov Motorsport and have also recently received a 2008 GSXR1000 model from Lee Stohr at Stohr racecars (I can pass on his contact details if it is any help) but any other models would be great to get a better idea of reasonable rear end packaging constraints.

[RaceMag]

Interesting points.
WRT the top #1. We can use a chemical fastener such as a loctite product should we need to. However we will only really know if it is a problem by trying it.
#2 - adjustment via a ruler or vernier in the slot? It is obviously a spaceframe chassis and frankly these are never 100% accurate and move during welding. If we can get placement to within 1/2mm that will be more than accurate enough give the intent of the design.

WRT second set of points:
#1 - not really. It is already heavily designed and the added flexibility outweighs the potential weight increase. We are not trying for BTDBTDBTD in this car - it is a 750cc car running on FF tyres as a beginners Formula Libre car. It has to be safe, reliable and sturdy in that order. Actual speed is less of an issue - at a projected weight of 285kg it will be fast enough. We already have a lightweight version in plan form, but need to know what suspension will work well etc.
#2 The weakest link will be the inboard pivot mounts, intentionally designed so.
#3 Well yes there is with a change in the top bracket on the upright - more work. This is two laser cut pieces of steel with a strap piece as part of the fabrication. It is intentionally easy to fabricate.
#4 Yes, probably quite right - but the purpose of the car is to give a couple of frustrated engineers and myself a good time competing against each other while we learn what works. If we have quick adjustability we can make changes, look at the data and make more changes and hopefully head in the right direction. If we find an 'ideal' we can of course fix it into that position (BTW bottom arms will be much more fixed).
#5 have modelled in in the home workshop. Drill hole through chassis tube top and bottom and then cut vertical slot between holes. Use a press to 10mm fold at one end of 2.5mm thick 40mm wide mild steel strip - height of slot set by length of strip. Repeat with equal piece. Oppose ends and weld together to make slot. Place into slot in tube and weld into place.

[RaceMag]

Funny error above - I was called away. I typed an abbreviated 'fastest time of the day' and it seems to assume I was being 'naughty'.
I forgot to mention that we have tested staking/broaching once. The engineering shop have used staking many times before. The test bearing failed with axial load before any slop was induced in the mounting.

The hubs are Honda Accord. Chosen for local wheel availability, brake disc availability, low(ish) weight and low cost. Driveshaft is a hollow honda item which will be lightened and we use the Honda T2 Differential from the DC2 Hondas.

I don't think we have a CAD model different tot he ones you have already mentioned. I'll ask. All drawings etc are available to members of our forum via the dropbox we use.