Curtis Youngblood's MUSCLE PIPES and Accessories

The muscle pipe increases the power of OS and YS engines (running 30% nitro fuel) by 0.3 to 0.5 HP. That's a BIG boost in power for under $100! This is a 15 - 25% increase in power. The Muscle pipe will also help control the engine RPM because of its steep power curve. Hovering dB level is around 88 dB (@ 1650 RPM from 3m), well within contest limits.

The header is pre-cut the proper length for the OS SX WC and the YS ST2. Just put an 1/8 inch gap between the pipe and the header (each in their stock lengths) and the pipe will be tuned. The power curve of the Muscle pipe is very steep in comparison to standard bolt on mufflers. The Muscle pipe's power curve is also centered around a lower engine rpm than most mufflers. Below is a quick chart of the optimum RPM settings for different gear ratios.

The flying RPM is what the model should tach during forward flight. Load RPM is what the model should tech through loops and vertical power maneuvers.

Mixture- For acrobatic and hovering it is good to run the mixture on the rich side. If it is run lean the engine tends to misfire and pop loudly. Also a lean run will tend to wear the engine badly. 

Mounting- Use the steel mounting strap with the silicon insulating sheet between the strap and the pipe. It is best to place the strap on or near the weld seam line on the pipe.Clamp the steel strap to a block of wood that is then bolted to the sideframes or clamped to the tail boom. It is important to use the silicon sheet and the wood to help reduce possible radio interference problems from metal to metal noise. Also, do not tie down the exhaust stinger. The stinger will fatigue if tied down.

Aerotrend Ultra Blue coupler #1039 lasts the longest. You need about a 2 inch long section of coupler for the pipe. With an 1/8 inch pipe/header gap the coupler should last about 40 flights. When using tie wraps to hold the coupler to the pipe and header, make sure to retighten the tie wraps after the first few flights. The tie wraps will loosen under the heat initially and the pipe may tend to move and hit the header or come off.

There are two Headers available- A "Right" (Rear facing engine) and "Left" (Front Facing).

When you first receive the Muscle pipe, shake the pipe to make sure there is no loose material in the pipe. Any loose material can be shaken out the main intake tube. Also push a 0.062 inch (1.5mm) drill bit through the exhaust pressure tap hole to make sure it is clear.