Traxxas Nitro V

First written: July 11th, 2006 | Updated: January 6th, 2009

A friend of mine bought a TRAXXAS Nitro Vee and we decided to get some experience with this model. And we had lots of problems…

 

 

The fun part…

This boat returned from the dead. The beginning was terrible. Lack of experience and some basic mistakes on the design of the boat, almost made us cry and scream…

What we know after 24 (yes, that’s twenty four) hours of running time

Now, after all the run time accumulated by the .12 engine we can take some conclusions about all the modifications made to the boat.

1.	Good cooling helped this engine survive 24 hours of run time. The first piston and liner only lasted about 1 hour of running at higher than adequate temperature. After a run, a drop of water would evaporate immediately. Now we can touch the head after a 20 minute run. The cooling capacity just wasn’t enough with the very thin tubing installed on the kit. Changing this is an absolute necessity. See Tips.
2.	The Octura propellers are much more efficient than the plastic prop included on the kit. Whether you have the .12 or the .15 engine you’ll get more performance from it with an X440 or X442 prop. However, higher the speed, bigger the problems. The boat can start to show some handling problems when turning to one side. Spins can start to happen. See the outdrive effect.
3.	The exhaust tubing will burn close to the metal manifold. It collapses a little bit and the gas temperature is very high on that location. There is no solution for this other than changing the tube with a more resistant one. We changed it for high temp silicone tubing for tuned pipes. It lasts a lot longer and it doesn’t collapse as much as the original.
4.	The fuel tank lid will crack. Have at least one replacement at hand. Nothing is more frustrating than returning home just because that little insignificant part doesn’t work anymore. The price is low and you’ll be prepared.
5.	Some cracks will start to appear below the muffler, caused by the high temperature. Just try to keep the hull in one piece. A layer of epoxy below the muffler will avoid severe cracking. Or you can just put a tuned pipe on the boat and see it fly… Chances are that you can cause cracks somewhere else on the hull
6.	The little engine is resilient. It only shows some erosion of the chrome layer on the liner close to the exhaust port. This is perfectly natural for this run time. This running time would be equivalent to 144*10 minute flights on an airplane engine (if it doesn’t fall from the sky long before…) with the rpm on the 10.000-13.000 range, usually at half throttle most of the time and only the good ones show some health with this kind of use. It’s really a pretty good engine.

 

Some technical info After some modifications, the boat became an incredible speed demon. We are running it on the limits. The steerable outdrive and the speed will make it spin if we don’t take care. But in the end, we can get 20 minutes of running at full throttle and lots of adrenaline. What is amazing with this boat is the fact that it was a slow and sluggish boat with the standard propeller. An OCTURA X440 turned it into a fast and fun boat. No more launching to reach plane. It will plane with no help in just a couple of meters. However, the outdrive effect is amplified with the higher thrust we get from the prop.

On a monohull which banks when turning, a steerable outdrive will point downwards and lift the back of the boat, causing it to spin out.

And now the problems…

Here we started to understand that we have to check all the screws before going to the water.

This is the boat at full speed with the original propeller. Below is a photo of the boat with the OCTURA and you see the difference…

The first 3 days

As you can see our first three days at the lake were not very rewarding. We had all sorts of problems because of inexperience and mechanical failures. The boat seems to be almost tuned, but we will only know when everything is checked and rechecked.
This boat made me think that this kind of hobby can be very disappointing.

And it was…

The reason for these problems was very simple. The cooling system had very thin tubing, and on the first day we inflicted damage to the piston and liner equivalent to a complete year of use. The engine stopped over and over due to overheating. A complete remake of the cooling system was enough for longer and cooler runs.

Can you tell the difference looking at the pictures below? Do you see what a good propeller can do?

A new piston and liner revealed what we already knew. They were ruined!
Now the boat is fun ! It gets on plane easily and the speed is much higher than we ever saw (even on the first day).

However the original propeller cavitates enough to overheat the engine when trying to get on plane. An Octura X440 cured this.

A TRAXXAS .15 is waiting to be installed. When the .12 dies.

The marketing guys (I’ve been one of them for a couple of years, and I knew how to turn serious shortcomings into thundering victories) never cease to amaze me: TRAXXAS says that they put the best propeller on the boat…(look at the pictures and judge for yourself) I don’t think so. The original propeller is really bad, and makes a fun boat become a nightmare. The expense that my friend had with the boat was enough to buy a first class hull and engine. If only the cooling system and original propeller were better, we would never had the idea that the boat is worthless. For a couple of dollars more TRAXXAS is ruining their own reputation.

When I read the reviews about the boat I wonder if we are special (accident prone) or if the reviews are biased to please the maker of the boat. The last review I saw had only good points and no inconvenients (I wonder how they did it). The rec.rc.models.water guys have very different opinions.

 

 

 

Tips

Substitute the cooling system tubing

This is probably the most serious shortcoming of this boat. If you run it for some time, with a leaner mixture than the ideal is almost sure that the engine will overheat. If it does, your piston and liner will be ruined pretty quick. In our case it just took a couple of hours. After that the engine would not rev up and the carb settings were impossible to adjust.
The plastic pickup tube was switched for a brass tube (4mm inner diameter) mounted on the same plastic base. Just cut the old plastic pickup and drill a hole a little bigger than 4mm on the plastic base. Insert the 4mm brass tube with a 45º cut on the lower extremity. Change the tubing for a larger diameter silicone tube and you’re done.
There was another modification we made on this – The hot water now leaves on the side of the boat instead of traveling to the rear of the boat. Less tube, less friction = more water traveling on the system = more cooling capacity. Now the water is ejected about 40 cm to the left side of the boat when running at full speed. Even with the RTS system running some water passes through the head.

Change the propeller

If you want good performance, you need to change the original propeller. This boat had a molded propeller impossible to remove from the shaft. 2 new shafts were made on a lathe – one for 1/8" propellers and other for 3/16" propellers. Because we use OCTURAS above X435 we just use the bigger one. I understand that OCTURA makes an adapter for this boat – PN OCGCSS (I suspect that someone at OCTURA tried the boat and found the same problems we did).

Change the turning fin (if you want that little extra speed)

We got rid of the turning fin. It makes the boat unstable when turning right. It’s not placed correctly (perpendicular to the V and aligned with the hull strakes) and causes the curve radius to be too big. When we force it the boat spins and leaves plane.
Additionally because of incorrect position causes drag making the boat turn right. We have to adjust radio trim to the left and instead of having a perfectly aligned thrust line, we have opposing forces instead of forward thrust.  A new Prestwich Model turn fin will be installed correctly (perpendicular to the V of the hull).

Review

Present config.

Motor	Traxxas .12
Fuel	10% nitro, 12 % synthetic oil, 4% castor
Propeller	OCTURA X440 (surface piercing)
Receiver	Multiplex UNI 9
Throttle	Multiplex MS 12
Steering	Multiplex MS 11
Radio pack	Dry Cells with voltage regulator (Home made)

 

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