jbeech
rrAdvertiser
Location: Sanford, FL (Orlando area)
| The Tiger doesn't come with a muffler. We considered this issue and just as with blades realized we couldn't win. In essence we realized half the folks out there would toss a cheapie because it would be inadequate for their needs, and the other half wouldn't want to pay for a real performance muffler (especially considering their cost). Of course no muffler is truly free, you pay for it regardless of whether it's rolled into the price, or not, so we instead decided to offer a 50-class model at a 30-class price and part of the way we do that is to leave the muffler decision to what works for your budget.
We offer a $19.99 PDR0068 2-pc muffler and a $74.99 PDR0053 Promuffler. Both are available to fit the Tiger (and other 50-class helis).
On the one hand, the 2-pc is nicely suited for a standard 50SX, especially if the modeler is intent on learning to fly and/or just wants to fly around for fun. Performance is on par with ordinary 1-piece units (all designed for 46-class engines which have been relabeled as being for a 50 - which are what dominate the market). This is a pretty decent choice if the budget is tight because it'll get you in the air while you're learning (or until your skills advance to the point you can tell the difference). This unit works particularly well for scale applications (where he rotor disk is run at 1650 RPM or less) and is nifty because the exhaust points straight down so it's very quiet and easy to plumb the exhaust straight out of a fuselage.
On the other hand, the Promuffler is designed specifically for the 50SX Hyper, and is a true 50-class performance exhaust system (i.e. one which allows the engine to breath and performs optimally). The fact is, the overwhelming majority of so called 50-size mufflers are identical to what was offered for the OS46 (before the OS50 ever became available) and are in fact simply re-labled as 50-size mufflers because they would bolt up. This situation is exacerbated by the Hyper which is in a whole other class of power and thus, the Promuffler shines because the Promuffler is designed specifically for the Hyper!
The reason a system which is designed for the Hyper is important is because it allows the Hyper to breath, and this is important because of the class of maneuvers 3D mavens using the Hyper are performing. I.e. maneuvers which are especially demanding of the engine in the mid-range and on the top end. The Promodeler muffler is particularly well suited to the all important mid-range because it's where the engine spends large amounts of time and where it really needs to makes its power. This is important because the mid-range is where the engine is most in need of the engine's maximum torque because the rotor disk wants to slow down (during maneuvers which load and unload the rotor disk - like piro-flips and tick-tocks).
These are maneuvers where the engine is transitioning through the mid-range (precisely where narrow-band tuned mufflers usually fall flat on their faces because those types are tuned for maximum RPM only) and on top of this, those types are unusually touchy with the needle settings to boot! Not to take away from these types of exhaust systems, they are superb on the top end, but you can't get something for nothing, and their high end boost of the power comes at the expense of the mid-range. This is unfortunate because the mid-range (where the tuned mufflers are somewhat muted in response) is exactly where you need the power!
Hence, mid-range is arguably the most important area of the power band and helping the engine make peak torque in the mid-range helps make power-sapping maneuvers like tick-tocks and piro-flips easier to perform because you can maintain the acceleration of the rotor disk. Folks, as all hotrodders know, peak horsepower is pretty on a plotted curve, but torque is what keeps a rotor disk spinning. With the Promuffler, we tested empirically and designed for maximum torque production. As a result, you get very good top-end power, superb mid-range power, and along the way, the engine is easier to tune and adjust and doesn't fall flat in the mid-range.
Want proof of all this? Use an optical tachometer and observe the rotor disk as a model is piro-flipped or performs tick-tocks and you'll see that the disk really slows down, in some cases quite a bit (even with a governor) and thus, the rotor disk must be re-accelerated back up to speed to complete the maneuver. Next, observe the collective stick on the transmitter and you'll see the engine is actually spending quite a bit of time transitioning through the mid-range for much of the maneuver. Naturally, since you can't even get to the top end power range without first going through the mid-range, the importance of excellent throttleability and mid-range power is of prime importance. Plus, overall, the model spends much more time in the mid-range than in the top end of the power curve. Hence, the reason we optimized the Promuffler for mid-range torque production!
John Beech - GM (and janitor)
Audacity Models |
