# P-3 Diesel Locomotive Contstruction log



## Bob Pope (Jan 2, 2008)

Time for me to get motivated and start on my third generation internal combustion/electric locomotive. All the components have been selected and purchased.

Type - Double-ended B-B freight locomotive. My goal it to make this as short and compact as I can.


Features from existing locomotives:
Engine - Traxxas 3.3

On-board starter (radio controlled)
Alternator 
720 ml fuel tank for endurance of 3+ hours
Aristocraft B-B trucks

New Features:


Telemetry for engine RPMs, Engine Temperature, Alternator volts produced. Real-time telemetry is shown on a display on the Spektrum DX-8 Transmitter.
Remote switching between series and parallel connections to the traction motors. A heavy train can be started with the traction motors in series and then switched to parallel. 




Photos to come! First thing is to get the engine modified. 


Bob


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## Stan Cedarleaf (Jan 2, 2008)

Sounds like a very ambitious project, Bob..... It will be fun following the progress.


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## Shay Gear Head (Jan 3, 2008)

Bob,

You will obviously have it ready for the drawbar pull at Diamondhead this coming January!


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## rodblakeman (Jan 2, 2008)

Hi Bob, Good to hear you are building again and not out "Dogn" with Bill and co ..


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## Bob Pope (Jan 2, 2008)

Here are some photos of the real diesel engine for the P-3 - yes this is a Davis Diesel conversion for the Traxxas 3.3. I ran it on the test stand today powering the tracks and running an Aristocraft SD-45 (with two motors per truck instead of one). 

It ran cool, was economical on fuel, had plenty of power, and smelled like a diesel. Smoke was gray with no hint of the blue you get from a glow plug engine. I think I need a smaller fuel tank and a bigger gunk tank than the glow engined P-1 and P2.


I don't think the on-board starter can overcome the compression of the diesel, so I'll probably stick with the Tiger Drive that you spin with a cordless drill.

Next up, install the telemetry radio gear (Engine temperature, RPMs and Alternator Voltage appear on the transmitter!). 


Thanks,

Bob


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## Shay Gear Head (Jan 3, 2008)

Bob,

Look forward to SEEING your progress at DH!


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## Phippsburg Eric (Jan 10, 2008)

Bob-- 

Can you tell us more about the engine? It looks like a standard hobby (model airplane) engine. it looks like a custom made cylinder or head to fit the stock engine? Did you do the conversion?


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## afinegan (Jan 2, 2008)

From what I can tell, its a Traxxis 3.3 model RC car nitro engine with a new head and connecting rod (to deal with the higher compression that diesel brings about)

I am pretty sure he purchased the TRX3.3K -TRAXXAS 3.3 Diesel head assy. including heavy duty connecting rod

He probally purchases the fuel from them also (I don't know enough about it, so I couldn't tell you if you can run the low sulfur diesel from the gas station)

More info on the davis diesel conversion go here:
http://davisdieseldevelopment.com/ 

Maybe he can get it to run on cooking oil, so when his train goes by, it will smell like hamburgers  (I know there are conversions for full size diesel cars hehe)


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## Bob Pope (Jan 2, 2008)

That's correct, it is a Traxxas 3.3 with a Davis Diesel head and connecting rod. It also has a Tiger Drive starter (that you turn with an electric drill). The slide carb was replaced with an OS-Max 11L rotary carb with an extension lever for finer control. I only use about 1/4 throttle for maximum speed. To improve idle, it has a heavy flywheel by MIP. And to get the clutch to engage at lower RPM I drilled five 3/32 holes in each clutch shoe and added brass pins for extra weight. And lightened the clutch spring. 

Silicone fuel lines have to be replaced. 

You have to run special model fuel - also from Davis Diesel. 

Other than that, it is pretty much stock! 

Here it is on the test stand. Videos to follow!















Bob


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## Bob Pope (Jan 2, 2008)

I'm abandoning the Diesel engine and sticking with glow plugs.

Reasons:
1) I could not get a reliable low speed idle (compared to the glow engines)
2) The on-board starter will not work - it requires a cordless drill to start. The idle problems and cordless drill starting became a pain even on the test stand.
3) Gunk to fuel ratio was about 50% (150 ml of fuel left 80ml of gunk). 
4) Smell - some people love the smell - I don't. It is also much stronger than with the glow plug engines. If build with a diesel, I would not store the locomotive inside.

Maybe these results were due to my lack of experience with diesels - but the benefits (power, fuel economy, being a diesel like the real thing) did not outweigh the problems. And even if the idle and gunk could be fixed by someone more experienced, nothing can be done about having to lug the cordless drill around, or about the smell.


Bottom line - I could make a diesel, but it wouldn't be better than the glow engines which are less expensive and readily available (along with parts and fuel).

Here is the engine I will use for the P-3: 

Traxxas 2.5, electric starter. I'm using the smaller (.15 size) 2.5 instead of the 3.3 (.20 cubic inches). The power curves between the 2.5 and 3.3 are close at the low rpms that I operate at. I'm going to try a 22 tooth pinion instead of the normal 24 to let the smaller engine work at slightly higher rpms.


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## steveciambrone (Jan 2, 2008)

Hi Bob, 
I remember a friend of mine had a model airplane which he tried a diesel on it and the smell and gunk was awful. The diesel fuel for these small engines contains ether which really stinks, and the gunk is black as coal. Tha Black gunk was all over the bottom of the airplane model. 

Steve


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## JPCaputo (Jul 26, 2009)

Suggestion for the diesel, try to run peanut oil ( that is what diesel intended his engine to run on ). Or vegetable oil, the clearest one you can find, it will have the least amounts of gunk.


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## Bob Pope (Jan 2, 2008)

I tried vegetable oil - it never started. I also ran the glow-powered P-2 - what a difference. Standard glow engines are the way (for me at least) to go. 

Thanks, 
Bob


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