1938 Mack FH Dump Truck

[j hancock]

These fellows were inspecting closely the chain drive on this heavy duty FH. 

No. 60 of 265 FH units built between 1937-1941.

[VaPatentman]

Sweet, 

[Hobert62]

Courious what would road speed be of a chain drive be?   

[mowerman]

yes very nice...bob

[j hancock]

57 minutes ago, Hobert62 said:

Courious what would road speed be of a chain drive be?   

Using different size drive sprockets, ratios could be changed relatively easily to adjust the effective mph of a vehicle.

In that time period, typical road speeds were 35-40 mph.  During WWII, there was a mandated 35 mph national speed limit.  I would speculate the FH did most of its heavy hauling work at 25-30 mph and 35+ mph running empty.

[blackdog2]

Talk to Chris b. when he bought it was started resto motor had bad vibration Matt Phall tuned the connecting rods around runs good know . 

[Hobert62]

That seams pretty fast with big chains like that flapping in the wind.  

[41chevy]

I had a set of 30 tooth primary and 40 tooth secondary sprockets made for my my AC and AC 6 that will allow 50+ out of them. They are copies of OEM Mack ones from the early 1930's. The orange AC with the diesel at the Winchester show does 60 -65 with the same set up. You have more chance of spitting the chain on a bicycle then the Macks.

Edited December 5, 2017 by 41chevy

[j hancock]

12 hours ago, Hobert62 said:

That seams pretty fast with big chains like that flapping in the wind.  

At speed, makes for an interesting whirring sound! 

[fxfymn]

13 hours ago, Hobert62 said:

That seams pretty fast with big chains like that flapping in the wind.  

There were chain drive Sterlings that were used by Rosenfeld Concrete in Milford, MA  into the 1970's that ran at highway speeds. More moving parts and a greater parasitic power loss is why they ended, not because they couldn't do high speeds.

[Vladislav]

21 hours ago, j hancock said:

During WWII, there was a mandated 35 mph national speed limit.

What was the reason? Fuel savings? Was it for commercial vehicles or for everybody? Just have never heard about it.

[j hancock]

It was for everyone.  It was a measure to help conserve gasoline and rubber.  A lot of the natural rubber supply was now in Japanese or unfriendly control and synthetic rubber hadn't really come onto the scene.  Ration fuel and people drove less and with a national speed limit, they had to slow down and the tires didn't get abused and lasted longer.

[Vladislav]

On 05.12.2017 at 10:15 PM, j hancock said:

It was for everyone.  It was a measure to help conserve gasoline and rubber.  A lot of the natural rubber supply was now in Japanese or unfriendly control and synthetic rubber hadn't really come onto the scene.  Ration fuel and people drove less and with a national speed limit, they had to slow down and the tires didn't get abused and lasted longer.

Jim, thank you for pointing that out. For me it's an interesting page of history. And not American-related only.

[blackdog2]

MY grandfather had few back in the day  but my father went to WW-2 in 1938 to teach people how to operate /fly  b-52  b-17 bombers came home they were stiff butt a nocker loose up and runin

[Haybag]

Anyone have a guesstimate on how many FH's are left?

[j hancock]

My guess would be about 10-12 FH's. 

Chris or Pat can probably give an exact number.