Hawk Lancia D50

[chrisguyw]

Another old forum save..........

Long before Cartrix produced their Lancia Ferrari D50, our club started a class for 50's Formula 1 cars, and as I was in love with the Lancia D50, my only option was to use the Hawk kit, which was produced in the mid 60's ( I think ).

The kit was very basic....no interior, no driver, no mirrors, no gas caps, exhausts, windshield etc.,......all the little bits, that add up to a really accurate model, and even more frustrating , at the time of launch, it was priced at 49 cents!!!!..........considerably less than I ended up paying 40 years later. I shouldn't whine, as I ended up buying a few.

Anyway, I spent a lot of time, finding/building the detail bits, and the car turned out very well.................Now anyone interested can buy/convert a Cartrix and save a lot of time and effort.

The original model kit box.........








I built a fairly straightforward "flexi-board" design chassis.......this is my favourite design for slow motor/skinny tired cars.








As mentioned, I did end up poking around the parts box for a driver, dashboard, mirrors and gascaps.......and I had to make the windscreen, exhausts and front radiator grill.

Here she be.......The wheels are available from RSSlot, and are BWA clones (which are no longer available).......I have painted both the inserts, and the wheels......much more period correct looking!!










Cheers
Chris Walker

[GT40 Racer (DM)]

Nice work Chris very clean finish. One of my favourite cars as well.

[MrTin]

Very nice, crisp work. But RS wheels are not a clone of BWA. RS went to the same company that I found for Penelope Pitlane. Unfortunately that company now insist on much larger orders than when I first dealt with them on RS's and PP's behalf requiring a much larger outlay up front. I guess when you're dealing with a company that frequently remake components for Hewland gearboxes, you really have to sit in line for their skills and pay well for them. But, unlike BWA products they are still available from RS Slotracing. PP, alas, were sold on and recently PP's founder, Steve Ward, died.

Martin

[Historiceng]

Chris, this is very nice and lovely workmanship. I am expecting a Lancia D50 body for Christmas from my wife.. I would like to make a chassis like yours. Please can you point me in the direction of where I might find something similar to study, I wonder if you can explain a little about it's design for me? So far I have only built fairly simple chassis' for Harry's showdown.
Thank you.
Eric..

[chrisguyw]

Very nice, crisp work. But RS wheels are not a clone of BWA. RS went to the same company that I found for Penelope Pitlane. Unfortunately that company now insist on much larger orders than when I first dealt with them on RS's and PP's behalf requiring a much larger outlay up front. I guess when you're dealing with a company that frequently remake components for Hewland gearboxes, you really have to sit in line for their skills and pay well for them. But, unlike BWA products they are still available from RS Slotracing. PP, alas, were sold on and recently PP's founder, Steve Ward, died.

Martin

Hello Martin, Colin (RS) used to distribute Al's (BWA )wheels & inserts in the UK,.....when Al (BWA) stopped producing both wheels and inserts, Colin, (who still had a good demand for these) sourced and produced his own, (thank you Colin).
While I do not dispute they are from a different manufacturer, (nor do I know who sourced the manufacturer), the RS 15" and 13" wheels are dimensionally identical to the the BWA 15"/13" wheels (he used the old BWA wheels as samples),...so,...from a user perspective,..they are clones. Again, thank you Colin !!

Cheers
Chris Walker

[chrisguyw]

Please can you point me in the direction of where I might find something similar to study, I wonder if you can explain a little about it's design for me? So far I have only built fairly simple chassis' for Harry's showdown.
Thank you.
Eric..

Hello Eric, The chassis design on the Lancia D50 (and all the attached chassis pics.) are all variations of what is known as a "Flexi Board" chassis........they first started showing up in the early 70's, initially among the 1/32 club guys. and the design principle has continued to this day. with most high end commercial track cars incorporating the torsional rotation element.

Simply, the chassis is two parts..a front and a back section, joined by a pivot tube, with the torsional rotation (amount and stiffness) controlled by thin "torsion" bars, that are attached to the front and rear chassis pieces. This torsional flex, allows the outside rear tire to load progressively in a corner, enhancing grip, and also results in more consistent/smoother handling.
The flex is controlled by the dia. and length of the "torsion" bars attaching the front/back of the chassis.

Depending on the motor/tires/track grip/track layout, etc. the chassis will need differing flex characteristics.....eg. a low powered car with narrow tires, will benefit from a "softer" flex, while a stronger motor/grippier tires/faster track will need a stiffer flexing car. (I generally find that most folks build brass/wire cars that are too stiff torsionally.........for the type of car you are building, torsion bars of .030 piano wire are likely fine.
As a general rule, if the car chatters in corners, it is too soft, and either shorter or thicker bars are needed........initially I would go with thinner bars than you might think, and go from there.

I have attached a few shots of some F1 type "Flexi Board" chassis that I have built to give you an idea......all a bit different, but, the premise is the same.

Cheers
Chris Walker


Two square pieces of brass tube (round or square makes no difference),...with a pivot rod (piece of 3/32 axle, ..old 2mm motor shaft, ...063 piano wire etc.) inserted. Solder one end of the rod to one end of the brass retainers..........the other end of the pivot rod is inserted into the other retainer,.....but,....it is NOT soldered.......the front and rear parts of the chassis rotate freely on this center pivot hinge........the amount of flex is controlled by the diameter and length of the "torsion bars" soldered to the front/rear chassis halves.




On this chassis I have used round tubing for the retainers......I generally use some thin brass tubing over the torsion bars.....this creates a small standoff, so that as the chassis flexes, I have no fear that they will rub/interfere with the chassis movement.



The thin piano wire soldered across the top of both retainers, takes any slop out of the mechanical hinge......I normally use some .030 piano wire for this. As it sits on the axis of the hinge it does not add very much torsional stiffness, but, whatever it does add should be accounted for when choosing the dia./length of the outboard torsion bars.




This is the underside of my Lancia....on this one I have used square tubing for the retainers..cut into the front/rear chassis plates...looks a bit neater than round

Tip..!!..It is easier to build the chassis in one piece, without the center hinge...then cut the chassis with a dremel, and build/solder the hinge.

2nd Tip..!!..Use a jig (or make a simple one, or,...measure measure)...it is critical to have both axles absolutely parallel, and there is generally enough flex/slop in the hinge to make "by eye" alignment questionable.






This is a 1/32 Eurosport chassis, ( a typical design for this type of car) built last year........ a stupidly quick commercial track chassis,.......while the materials change, and EDM machines allow for some pretty funky cuts,...the premise is the same, with a central pivot bar, allowing for torsional chassis rotation.

[mattb]

Chris I feel bad enough when I see the great models you build and the fantastic detail. Now you make me look at all that great chassis work. You sure do great builds.

mb

[Historiceng]

Chris, thank you very much for taking the trouble to explain so comprehensively... and those chassis'... wow, they are a jewel, absolutely astounding.
I am going to give this a go for my Lancia ..... hoping santa keeps his word and brings the body!

[strummer57]

I remember buying one of those back in 1970-'71; I paid the price printed on the box...49 cents.

I was a little disappointed in that it's wheels/tires were molded in the same ( grey or off white?) plastic as the rest of the car; no chrome wheels or "rubber" tires here!

Anyway, as usual Chris you have shared more great stuff; thanks!

Mark in Oregon

[Barc 1]

That chassis is a work of art

[Mickey thumbs]

Another word of thanks, Chris, for the detailed explanation and pictures of the flexi board design. I’m moving on from the 60’s iso-fulcrum chassis series I recently built and moving into the 70’s. Planning to do a SW or AW version of the flexi- board for a Porsche 910 and an inline one for a 904. Still counting my brass chassis historic builds on my fingers since returning to slots so they aren’t very pretty, but I’m having lots of fun building my way through slot car history as I dropped out around 1968.

And thanks again to everyone here at HRW for all the help I’ve received over the last year or so.

[mattb]

Guess I'll just throw away my soldering iron!

[chappyman66]

I keep hoping someday I will make something like this....but it never turns out that way. Best looking Hawk, by far!

[Mickey thumbs]

So far, so good with my flexi-board build. Core of chassis as described above is done. It is for a sports car body, so if I want to add side pans is it best to attach them to the back (motor) half or the front axle half? They will not be used to mount the body so they would be free to move with either half.
Please don’t suggest fastening to both using some sort complex hinge gizmo! LOL😄
Mike

[chrisguyw]

Hi Mike, I think you will appreciate the handling characteristics of a "flexi board",.............a big step up from a pure iso, which has some inherent issues.

Please post a couple of pics., .....this will allow me to give you better direction, depending on how you have built the center section, and torsion bars.

Most of the better performing "Flexis" have the pans attached at the front of the chassis, with some support at the rear.....the rear support is to keep the pans from flexing outwards, and uses the main chassis rails as downstops.

The following pic. will illustrated this........a wire cross brace is soldered to each pan, and passes through a slightly larger dia tube/square soldered to the main chassis.
This crossbrace adds support to the pans and, by passing it through a larger dia tube.square, it acts as an up/down stop, and.......critically allows the chassis to flex torsionally.
Depending on the thickness of your main rails and pans, you may need to solder some brass shims to the pans in order to have everything sit where you want it.....see pic





For the front attachment, use some thin .032/.047 wire bent into "L's" and solder these to the front of the main rails, and to the front edges of the pans.

This pic., shows the attachment of the pans at the front.

Depending on the thickness of your main rails, and, which motor/tires you are using, you may be able to attach the rear of the pans to the main chassis rails, using another pr. of thin guage "L's",......as can also be seen in the pic. below............(Attaching the pans front and rear WILL make the chassis stiffer torsionally, which you may or not want, again, depending on you main rail thickness, length/guage of your torsion bars, motor, tire/track grip





If you really want to get funky, you can build a "plumber" front end...............brass tubes are soldered to each side of the front of the guide tongue.....wire "L's are inserted into these tubes, and run along the length of the chassis, with the pans soldered to them......a front and rear cross brace are required to hold/support the pans.

This chassis is not the best illustration, as it does have some other hinges etc., which mat make it a bit confusing, but you can see the brass tubes on either side of the guide tongue, with the wire "L's" running back along the chassis.





Mike, if you can post some pics. of progress to date, it would be helpful.

Cheers
Chris Walker