Building the Marmon Wasp

[Audi1]

Back to the Wasp.............

A few more parts arrived today from Pendle in the UK (purchased prior to Brexit). They're wheel/tire combinations and are an important part of the build of the Wasp, since the wheels/tires were such an overpowering part of the car. Here are some pics of the choices that I now have, along with some key dimensions:

1. Penelope Pitlane 19" wheels with Penelope Pitlane Vintage rubber tires:



Wheelbase - 78mm (or thereabouts; probably shorter than that in the end)
Track - 57mm max (will likely be more like 50mm when complete)

Wheels - 22.25mm diameter
Wheels and tires (mounted) - 27mm (tires 7mm wide)
Ground clearance - 16mm (this is astounding to me - I'm usually working with 0.8-1.0mm clearance; 1.2mm being high, 1.6mm being too high.............)

2. CBDesign 16.5mm wheels with PCS 32246/t rubber tires:



Wheels - 16.5mm x 7mm diameter
Wheels and tires (mounted) - 24mm (tires 6.7mm wide)
Ground clearance - 14mm

Here's the best pic that I've found to go by, I think it's a pic of the car with Ray Haroun right after the first Indy win:



I'm leaning more towards the CBDesign wheels/PCS tires (which will be trued down some after gluing them on). I think that the Penelope Pitlane wheels/tires are too high for the model and there is no way that I can drop the frame down lower; due to the shape of the body; particularly in the area of the cockpit floorboards.

So, what say you all..................?

Allan

[Z-carfan]

Looking good sir. I lean to the CBDesign look, I feel the PPL setup is too tall. IMHO.


Sent from my iPad using Tapatalk

[Retro Racer 44]

Hi Allan, it is great to see your progress. I felt a bit exploratory tonight so I held a ruler to the screen to compare the pics. Using the b&w pic of the original car, and the pic with the CB wheels, I found the following:

Dimension, B&W pic, resin pic, ratio

Overall length, 8", 6.5", 1.23:1

Wheelbase, 5.25, 4.5, 1.16:1

Tire diameter, 1.75, 1.375, 1.27:1

Height chassis to ground, 1", 1" 1:1

Overall height to cowl, 2.25, 2.25, 1:1

What does this mean? If we take the b&w pic as the reference, then the overall length should be 1.23:1, and the other ratios should be close to the same.

When we do this, the wheelbase should be 4.25", the tire diameter 1 7/16", Chassis to the ground would be 3/4 inch, and the overall height would be 1 7/8".

This would show that your wheelbase to length comparison is close, and an eighth of an inch at either end would bring it in line. The tires are 1/16 too small, not enough to worry about. The chassis to ground, from bottom of rails in the centre of the car, should be a quarter inch lower, and the overall height to the cowl from the ground is 3/8" too much. These measurements could be easily fixed by setting the body 1/4" lower on the axles. This would also have a positive handling benefit.

Of course if you want to be perfectly accurate, print the pic and measure the distances, and then do the comparison to the real model. Since the focal distance and sizing were different on the two pics, I didn't compare them both.

Hope this was helpful,

Keith

[Audi1]

Hi Keith,

Thanks for taking the time to go through those measurements/calculations. The real problem is that the body of the car is over-scaled; it's more like a 1/36 than a 1/32, which makes fitting 1/32 parts to it a challenge. And the cockpit sides are cut down further than they should be; making the motor armature/driveshaft placement a problem.

There is no way to drop the chassis lower, due to the fact that I need motor armature clearance under the cockpit floorboards, which prevents me from being able to cut the front and rear axles up into the body. At the same time, if I were to fashion a front drop axle from brass/piano wire (like the original), then I would be left with quite a rake from the rear to the front, because the motor armature clearance problem prevents me from similarly moving the rear axle up.

Here's how the 1:1 car got the front lower:



And, they had no driveshaft clearance problems with the car, so the rear could come down, too. With the body that I'm working with, unless I run the armature and coupling through the torso of the drive (which I don't want to do), then I have to leave the rear axle position as it is now (it may even need to be a little taller.............Yikes!).

One more pic; which I think is pretty accurate for the 1:1 car:



Even though I anticipate that the slot racing performance of this car will be abominable; due among other things to the very high CoG (I can hardly wait to fashion the guide tongue for this car.............), I have to say: Go you Wasp!



Allan

[Audi1]

Bet you all thought that this project was toast............... but, it's not...............I'm just slow getting it off the ground..........................because it's been a conceptual challenge to develop a chassis that works with this very narrow body.

Here are the chassis bits, roughed out and ready for assembly:



It's going to be a very simply chassis, since the main challenge is just getting a chassis - any chassis - under this over-scaled model of the Marmon Wasp.

The chassis is going to be somewhat monocoque-ish, with the motor and the rear axle holder being an integral part of the chassis itself. We'll see how that works out................

Will post some more pics once the chassis is put together.

Matt at Changing Gearz has designed some wheel covers for the Wasp that are truly authentic; easily the best part of the car. He brought them over the other night and they are correct all the way down to the valve stem cut-outs. He does unreal work in 3D design! :music-rockout:

Allan

[TsgtRet]

Outstanding work (as usual).
Wondering how you're going to simulate the "oblongish" appearance of the wheels in the period photos :lol:

[Audi1]

Since I mentioned the Changing Gearz inserts, I thought I'd put up a pic of them:



Top row, starting from the left left, the CBDesign 16.5x7mm wheel with glued and heavily turned down/trued PCS vintage rubber tire, the same wheel/tire with a front wheel insert, and the back of the wheel, which I'm making the same color as the body.

Bottom row, three of the inserts un-mounted. Note that the Wasp had quick change front wheels and, hence the "knock-off" type of hubs. The rear did not. The mounted insert and the one on the bottom left have those pseudo knock-offs, while the two on the right do not.

As I mentioned before, the detail on these 3D printed inserts is really amazing! Don't forget to check out the valve stems in the elongated stem cut-outs.............. Thanks, Matt!

So, if the build turns out poorly, just concentrate on the inserts and you'll be OK................! :handgestures-thumbup:

Allan

[Audi1]

[Audi1]

Yes, the inserts have so much more detail than the body, that they look like they belong on a different car...............!

Soldering iron today...........we'll see how I goes.

Allan

[dge467]

Looking good! Those wheel inserts are awesome! Looking forward to your chassis build up.

[TuscoTodd]

Allan - it is awesome to see you moving forward with this! VERY cool car to build and those inserts from Changing Gearz - WOW!!!

[dreinecke]

I have similar motors in a few PinkKar bugs and agree that while great in size, they are seriously hampered by any weight. Pull the body and it works better without. The torque band is not very good either.

[Audi1]

No choice, Doc, this is an FF-050 slim can motor-only proxy.

Allan

[Audi1]

You know how in slot car building, you can be ready to do something, but it may not be ready to be done...............? Well that happened to me again this morning.

I was all set to fire up my iron when I thought: .......hmmm, monocoque-type chassis, motor as an integral part, will have to solder to the motor, better have my gearing all done before I do that because there won't be any more motor-out options after I solder to it.................

So, back to the motor/gearing I went. Of course, nothing fit. I messaged Chris Walker this AM about gearing for a slim can motor, because he does a lot of VRAA proxies which use, at least in one class, the slim can motor. But when I got in there, it became clear that I was going to be loving a 23 tooth crown..............because that's all that would fit from my Slot.It collection. Monkey wrenches galore! The Slot.It pinion that I used, was a very tight fit between the motor and the armature carrier on the crown. So, a little power-on sanding on the pinion, brought the outside profile down to something more conical. But, that was still not enough, so I mounted the crown on an axle, put it in my drill press and use a couple of very small flat files to take down the aluminum on the sides of the crown armature carrier. You'll see the evidence of file marks on both the pinion and the crown armature carrier. Not so easy to get the inner crown boss down without taking off the plastic teeth...............



It's tight now - but nothing binds. So, I'm thinking about firing up that iron again, or maybe hitting a bucket of ball at the driving range, or maybe grabbing a beer.............Maybe I better to save the iron until tomorrow morning................. :happy-partydance:

Allan

[Changing-Gearz]