MatraSport Forum
Each model => Murena => Topic started by: Jon Weywadt on April 10, 2011, 03:23:19 pm
-
Well Philbert and I are getting serious about trying to make new rear swingers.
The idea of a stainless steel version is dropped. Instead we have talked to an expert in bronce and aluminium casting, who informs us that it can be cast in aluminium and be just as strong.
We therefore need to get hold of a set of rear swingarms that are intact. We could of course take a set from one of our cars, but would hate not to be able to drive while this project is under way. Therefore, is there anyone of you Matraholics out there who has a spare set and would be willing to lend them to us. You would naturally get rights to buy a first set at cost. We are still trying to calculate what the final cost will be. After the casting, the parts have to be milled to fit bearings and bushings.
More on this project to come.
-
So, your idea is to reproduce the Bagheera arms ?
Can I just advise you to remember the fact that the Bagheera cast aluminium arms were calculated by the best rockets experts of the time.
And that during the tests, the Bagheera ... lost a rear wheel with the remains of the arm attached to it.
This is why on production model, around the bearing, there is a steel surrounding of 5 mm thick that prevents the arms from breaking.
-
I have a pair of solid good rear swing arms in spare to lend out if this helps with the project.
G.P.
-
I have a pair of solid good rear swing arms in spare to lend out if this helps with the project.
G.P.
That sounds great. Where are they located? or are you attending the meet in Kiel in June?
Jon.
-
So, your idea is to reproduce the Bagheera arms ?
Can I just advise you to remember the fact that the Bagheera cast aluminium arms were calculated by the best rockets experts of the time.
And that during the tests, the Bagheera ... lost a rear wheel with the remains of the arm attached to it.
This is why on production model, around the bearing, there is a steel surrounding of 5 mm thick that prevents the arms from breaking.
I know nothing about Baghera arms and was not aware that they had failures.
We are aware of the challenges and as a former 'rocket scientist', who worked for NASA for 20 years :D, I am confident we can overcome the challenges.
-
Now I understand.
Rocket scientists.
They were used to make projectiles for one time use only :P
-
Now I understand.
Rocket scientists.
They were used to make projectiles for one time use only :P
Yes but reaching velosities of 11.200 Km/second ;D I may yet have my Murena reach escape velocity. :o
-
I have a pair of solid good rear swing arms in spare to lend out if this helps with the project.
G.P.
That sounds great. Where are they located? or are you attending the meet in Kiel in June?
Jon.
No I won't be attending the meet in Kiel. They are in the U.K. so I would have to ship them to you.
Let us know your thoughts?
G.P.
-
---
No I won't be attending the meet in Kiel. They are in the U.K. so I would have to ship them to you.
Let us know your thoughts?
G.P.
Well, if you have a chance, can you then find out what it would cost to ship them to Copenhagen? I imagine, perhaps an outfit like DHL might be the cheapest way. If it is not too outrageous, we could add it to the startup cost and divvy it out over the probably many orders :D
-
O.K. I will take them off the car and weigh them for a shipping price.
G.P.
-
O.K. I will take them off the car and weigh them for a shipping price.
G.P.
To ship them to Copenhagen 26kg in total via DHL which is the cheapest is £50:00.
One still has the hub assembly and disc attached as you may want this to check assembly and clearances. I have also left the rubber bushes in the chassis points. Both are in pretty good condition but will probably require cleaning and shotblasting first.
If you are really serious on this project (as I do have my doubts about the feasabilty and the cost), I will send them to you at my own expense to get things started. A name and address will be reuired. PM these please.
G.P.
-
--
To ship them to Copenhagen 26kg in total via DHL which is the cheapest is £50:00.
One still has the hub assembly and disc attached as you may want this to check assembly and clearances. I have also left the rubber bushes in the chassis points. Both are in pretty good condition but will probably require cleaning and shotblasting first.
If you are really serious on this project (as I do have my doubts about the feasabilty and the cost), I will send them to you at my own expense to get things started. A name and address will be reuired. PM these please.
G.P.
Sorry. Have been goofing off on the Gran Canary island for a week of R&R. ;D It was great.
I will check how far Philbert has gotten talking to the casting company guys. But I'll say we are dead serious on this. More info later.
/Jon.
-
The idea of a stainless steel version is dropped
Just of curiousity, why?
-
The idea of a stainless steel version is dropped
Just of curiousity, why?
The cost of producing it in stainless steel is prohibitive. Also, it would likely end up being heavier which we did not like at all.
The cast aluminium option has the benefit of no rust and lighter weight. We believe we have found a place to machine the bearing and bushing holes in the cast piece. We still need to decide who will get the job of casting. We are aware that aluminium also is subject to corrosion, especially due to salt. But we are considering anodizing the finished swinger. (Making it possible to order them in the color of your choise ;D ) or powder coating. The latter may be the best solution.
-
Many grades of aluminium alloy or even magnesium alloys are available for casting suspension components. Here is quite a good link for deciding the most suitable for this application. Click the code number for full details.
http://www.creasey-castings.co.uk/materials.html
Anyone here a metalurgist or have some knowledge of the material type most suitable?
http://uk.ask.com/wiki/Aluminium_alloy#Automotive_alloys
I have seen aluminium swing arms on an old Porsche 944 Turbo which looked great.
GP
-
Any developments or shall I put the swing arms back on the car now?
G.P.
-
Any developments or shall I put the swing arms back on the car now?
G.P.
No, no. Not yet. Philbert and I are waiting on pricing. The guy wanted to do some figuring, before he gave us a price. So, the project is still on.
We are also looking at possibly allowing more space between the arm and the wheel rim, so wider tires can be fitted without spacers or different offset. If I remember right, there is only about ½" clearance on original wheels/tires and the arm. That won't cost more, once casting, but a bit of modelling (not fashion :D ) will be needed.
-
A bit more clearance will be a good idea. I was using a 215 size tyre on an ET27 rim and had some rubbing which made me drop back down to 205's. I would like to go back to 215's if possible, which this would achieve.
GP
