MUFFLERS & dB TEST FOR THE APEX

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Engine Not Running, 85-90mph Glide

97 dB

Trent Palmer's Freedom Fox, w/ Rotax 915is

WOT / Take-Off = 109-110 dB

Cruise = 100-101 dB

Notes: Trent's Kitfox is arguable the quietest plane around. So I thought it would be a good reference.

Burn's Stainless 2 Stage Race Muffler

WOT / Take-Off = 109-110 dB

8000 RPM Cruise = 103-105 dB

Part# SM-200-450-30-2S

Cost: $750.00 Shipped

30in Overall Length

Pros: Lightweight at 6.8lbs. Packing can be replaced. Deeper tone than all others which IMO gives an impression of quieter – not a high pitch like others.

Cons: Cost. Length at 30 inches will be difficult for most. Pretty much forced to mount completely under airframe.

Notes: This is the muffler I have decided to run long term. Despite the cost it is a quality product and can be serviced to replace the packing. The tone it produces seems to be a bit deeper which IMO is not as annoying and gives a sense of being even quieter.

Jones Resonator & MagnaFlow Straight Through, Glass Packed

WOT / Take-Off = 115 dB

8000 RPM Cruise = 106-108 dB

Pros: None Really!

Cons: Long in length. Heavy. Not that quiet. Jones Resonator not made very well and cracked two times. Do not recommend this setup at all.

Notes: This was the setup I test flew my plane with and ran for awhile until the Jones Resonator cracked. I fixed it and it cracked again. The complete package is just too heavy and not very elegant. And as mentioned, the Jones Resonator just isn't made well enough for this type of application.

Hayabusa, Single

WOT / Take-Off = 111-112 dB

8000 RPM Cruise = 107-108 dB

Pros: Cheap in cost. Relatively lightweight. Relatively easy to find on Ebay or Facebook Marketplace.

Cons: -500 RPM loss on Take-Off and +100F in EGT's. A inlet flange will need to be made and an OEM gasket purchased if you didn't get. I have the flange in a CAD file for cutting if anyone wants.

Notes: Although many have jumped to use this muffler in testing I was not happy with it. It wasn't overly quite but the biggest thing was the loss in RPM on Take-Off's and the increased EGT's.

AP “Turbo Style” Stamped Aluminized Muffler

WOT / Take-Off = 112-114 dB

8000 RPM Cruise = 108-110 dB

Part# APH-6519

Cost: $27.00

Pros: Cheap & Lightweight.

Cons: Aluminized Steel.

Notes: I actually ran this cheap/simple setup for quite awhile. It didn't honestly seem too loud and performance was hindered much.

Summit Racing Fully Welded “Turbo Style”

WOT / Take-Off = 114-115 dB

8000 RPM Cruise = 108-110 dB

Part# SUM-633250

Cost: $35.00

Pros: Cost.

Cons: Heavy, Steel, and not very quiet.

Notes: I didn't run this muffler long at all. Just nothing too positive about it IMO.

MagnaFlow Muffler

WOT / Take-Off = 116-119 dB

8000 RPM Cruise = 112-115 dB

Pros: Non really. Performance is not hindered at all with this muffler. It is a straight through, glass backed design.

Cons: Extremely Loud IMO

Notes: My wife flew with me the day I ran just this muffler and she actually asked me if something was wrong because it was so loud.