Which exhaust?
“What? I need to buy the exhaust seperately” you ask?? Yup, you certainly do! Buying the helicopter kit is only a part of it!
You need to buy the exhaust system seperately. You need it cause most engines won’t run properly without an exhaust system and in most cases the engine relies on the pressure generated from the exhaust to feed more fuel into the engine, but we’ll get to that later.
There are a few different types of exhaust systems. These are the muffler, the tuned muffler and the tuned pipe. All have different characteristics and will make your engine perform a little differently.
When you’re looking for an exhaust system for your helicopter, you’ve got to take into account a number of things. Some of these are:
- Does it match your engine? Some engines have different exhaust port mountings than others. You want to make sure that your selected system will accomodate your particular engine.
- Does it match your helicopter? Some helicopters may require different exhaust mountings due to their construction. This becomes more of an issue for tuned pipes where you may have to buy a different header.
- Does it suit your flying style? Some exhaust systems such as some tuned pipes, only really work at certain rev ranges (ie full throttle). This may not be ideal for you if you’re wanting to do a lot of hovering as most helicopters don’t hover at full throttle. In that case, maybe a good muffler or tuned muffler might be more beneficial.
- Does this exhaust system require different fuel mixture to run efficiently? Some exhaust systems run better with increased nitro content which will increase the cost of your fuel expenses.
- What reputation does this system have? Ask around and see what others think about your chosen exhaust system. There are some dogs out there that you’ll want to avoid.
Muffler
Mufflers get rid of the exhaust gas produced by the engine. The pressure generated by the outward flowing gas is then used to pressurise the fuel tank and push fuel to the engine’s carbuettor. Generally the engine will run fairly consistently (depending on how well you’ve set up your engine) throughout it’s rev range. Good for if you run a two speed headspeed setup (for hovering and fast forward flight) because the engine should run consistently.
Tuned Muffler
Tuned mufflers follow the same principles as standard mufflers but have been tuned to enable the engine to run optimally at a certain rev range.
Tuned mufflers are designed to try and get the best of both worlds of mufflers and tuned pipes. They’re very popular for people who want to run a two speed setup for hovering and fast forward flight.
Tuned Pipe
Tuned pipe’s are designed to make the engine generate peak power at full power. They’re most often used for pilots who do heavy aerobatics for 3D where the helicopter is always running at full power and has to make full power.
Final Words
I’d go for either the muffler or the tuned muffler when first starting out. Firstly cause you’re very rarely flying around at full noise, and they’re easy to tune the engine with. If you later decide that you want to do full noise aerobatics, go for the tuned pipe.
