Paramotor Thrust and Noise Test
Testing performed by Pat Barton (no dealer affiliation), Bruce Brown (Ohio Powered Paragliding) and Mo Sheldon (Airparamo)
Fourteen paramotors were tested for static thrust and "loudness" (sound pressure) between about 2:00 and 3:30 pm Sunday February 8, 2004 at the Paratoys Convention (held at the Salton Sea, CA). Mo Sheldon directed the thrust testing and provided the thrust test rig that included a commercial quality digital scale. The scale was zeroed before each thrust measurement.
Mo Sheldon and Bruce Brown each provided a Radio Shack dB (decibel) meter.
All data was measured and recorded by Mo, Bruce, Pat Barton, Francesco "Check" De Santis (Powerglider/U-Can-Fly-2) and Jose Casaudoumecq (Aerolight USA). Sound pressure levels were made using "A" weighting on the dB meters.
The environmental conditions were approximately 71 degrees F., and 1021 mbar barometric pressure.
Four sound pressure measurements were made on each motor:
- Approximate center of the pilot's head at full power
- Approximate center of the pilot's head with motor producing 50 lb thrust (simulation of level flight power)
- 15 feet to starboard and 3 feet forward of the prop hub, 3 feet above ground
- 15 feet to starboard and 3 feet forward of the prop hub, 3 feet above ground, with motor producing 50 lb thrust (simulation of level flight power)
It is important to note that the sensitivity of the human ear is in the range of 2-3 dB. In other words, a sound increasing in loudness from say, 80 to 81 or 95 to 96 dB will generally not be noticeable. A sound increasing from say, 80 to 83 dB will on the other hand be (just barely) noticeable louder to an average listener. When evaluating motor "loudness" data, it is practical to say that a difference of 1 or 2 dB between one motor and another is not significant. A motor that is on average, say 5 or6 dB "louder" than another motor is in fact significantly louder, and will be noticed by most listeners. Note that these rough observations do not, however, address frequency response and the human perception of which sounds (frequencies) are more pleasing (or displeasing) - these perceptions are quite complicated and to some extent subjective.
The following is a rough guide to sound pressure in decibels:
- 120-130 dB threshold of pain and hearing damage (depends on frequency and exposure time)
- 115-125 typical rock concert (front 1/3 of audience)
- 95-120 typical "disco" - on dance floor
- 80-100 typical wedding or small club band
- 55-75 normal conversation (at listener's ear)
- 20-30 light breeze through tree
Table 1 presents the thrust results for each motor unit along with prop style and pilot name (owner); these results are listed from highest to lowest measured thrust. The average thrust for all fourteen motors was 113 pounds (+20). The Simonini powered units generally produced more thrust than the other units, and if the Simonini motors are removed from the data set, the average thrust for the remaining ten units was 103 pounds (+10).
For each motor unit the four sound pressure measurements were added to yield a "thrust score": a simplistic representation of overall motor unit "loudness". Table 2 presents the sound pressure ("loudness") data for each unit, ranked from "quietest" to "loudest" based on the calculated thrust score.
Table 1: Paramotor Thrust Summary
|Unit Brand/Model||Prop Type||Thrust in lb||Engine Type||Owner|
|Walker Jet RR||51" 3-blade comp||160||Simonini||Dell|
|Sky Cruiser 200||46" 2-blade wood||138||Simonini||Steve|
|Fly Power Gold 130||51" 2-blade comp||133||Simonini||Mo|
|Fly Power Plus||48" 2-blade wood||124||MZ 34||Dan|
|Fly Power Gold 115||48" 2-blade comp||109||Solo||Hans|
|Homebuilt||45" 2-blade wood||114||Kaw 80||Alex D|
|Fresh Breeze 122||48" 2-blade comp||109||Solo||Hans|
|Homebuilt||48" 2-blade wood||105||Rotax 125||Alex B|
|Fly Power Flash||48" 3-blade comp||100||Sky 100||Javier|
|SD 48||48" 2-blde wood||98||Solo||Bob|
|Powerglider iFlyer||49" 2-blade wood||98||Top 80||Check|
|Fly Power 130||50" 2-blade wood||95||Solo||Pat|
|MiniPlane 125||49" 2-blade wood||90||Top 80||Scott|
|Sky Cruiser 100||48" 2-blade wood||93||MZ 100||Tony|
Table 2: Paramotor "Loudness" Summary
|Unit Brand/Model||Full Power Pilot||Full Power 15 ft||50lbs Thrust Pilot||50lbs Thrust 15 ft||Score|
|Sky Cruiser 100||115||96||103||87||401|
|Fly Power Flash||116||97||104||86||403|
|Sky Cruiser 200||120||104||106||89||416|
|Fly Power 130||119||99||109||90||417|
|Homebuilt - Rotax||119||103||105||90||417|
|Homebuilt - Kaw||116||103||107||91||417|
|Fly Power Gold 130||121||106||108||92||427|
|Fly Power Plus 122||122||106||107||92||427|
|Fly Power Gold 115||123||105||111||95||434|