23: Motor & Propeller
There’s a lot going on with motors and props. Thrust, torque, sound, strength, cage size, etc.
Misinformation on torque and other bits can be delivered with religious fervor. It’s still wrong. I’ve worked with other respected pilots and aerodynamic experts to get reliable info into the PPG Bible. Here are some highlights.
Here is a great video showing how a 2-stroke engine works and how a membrane carburetor works. It’s intent is to show servicing of Walbro carbs but it’s very informative.
by Jeff Goin | Jul 24, 2020 | 13: Flying Cross Country, 22: Aerodynamics, 23: Motor & Propeller, 26: The Wing, 27: The Motor Unit
Here is how to maximize range for the current wind conditions. For crosswinds, see below. First, a few comments about the problem. It’s covered briefly in the PPG Bible but here is more detail. As the book says, use best glide speed in calm wind, fly faster in a...
by Jeff Goin | Nov 23, 2019 | 02 Gearing Up, 23: Motor & Propeller, 27: The Motor Unit
See Paraglider Certification There is no paramotor certification. That’s too bad because there is a lot of room for improvement, especially regarding prop-strike protection and torque mitigation. I can imagine a fairly simple set of tests that result in a safety...
by Jeff Goin | May 14, 2019 | 23: Motor & Propeller, 27: The Motor Unit, Mx: Harness Setup
To fully understand the many harness permutations and terminology, check out Harness Systems. Of many harness and motor adjustments, setting the proper motor hang angle affects far more than comfort. As covered in Chapter 12, correct setup can make or break launches...
by Jeff Goin | May 4, 2019 | 23: Motor & Propeller, Mx: Motor
Estimate the percentage of ethanol in pump gas, courtesy Conoco, Inc and EAA.org. See also All About Fuel. Most paramotor pilots use pump gas as opposed to avgas. In all likelihood, that means you’re getting alcohol, specifically ethanol, in your fuel. How much...
by Jeff Goin | May 4, 2019 | 23: Motor & Propeller, Mx: Motor
Extracting this much power from such tiny, lightweight motors, requires great care. The following will help you to make the most intelligent fuel choices for your favorite propulsion. Excerpted from Group K Technical Documents. See also Alcohol in Fuel, Does AvGas...
by Jeff Goin | Apr 30, 2019 | 23: Motor & Propeller
This is one of the most confusing aspects of paramotor dynamics. Here are the basics: Various torque effects conspire to twist your body left (belt drive), redirecting thrust that now pushes your body left, which causes the wing to bank right like in the illustration...
by Jeff Goin | Apr 30, 2019 | 05: First Flights, 22: Aerodynamics, 23: Motor & Propeller
If you remember one thing about Loaded Riser Twist, it should be: At liftoff, if the wing is leaning right, your body will tend to twist left. Thrust will push your body more left, aggravating torque twisting effects It isn’t related to torque directly but it...
by Jeff Goin | Apr 29, 2019 | 19: Risk & Safety, 22: Aerodynamics, 23: Motor & Propeller, 26: The Wing, Advanced Launching
Some wings, when combined with some motors, will oscillate. You swing back and forth in shallow little banks with no pilot input. It’s caused by a variation of Loaded Riser Twist where one riser has more load than the other–a fleeting condition that...
by Jeff Goin | Apr 23, 2019 | 12: Maintenance, 23: Motor & Propeller, Mx: Troubleshooting
It’s always good to support your local dealer to better ensure he/she stays in the business of providing support. But it’s also nice to know where parts are available can get you airborne when the dealer is unavailable or is not providing good service. As...
by Jeff Goin | Apr 23, 2019 | 22: Aerodynamics, 23: Motor & Propeller, Mx: Motor
Which prop you choose depends on which redrive you have. A high ratio means the prop spins at a slower speed and needs more pitch–a bigger bite. At some point of increasing pitch, efficiency suffers and/or the motor will bog down and won’t get up to its...
by Jeff Goin | Apr 23, 2019 | 23: Motor & Propeller, Mx: Troubleshooting
Causes and cures of this motor killer Heat is a paramotor’s mortal enemy. Worst cases have the piston welding itself to the cylinder wall in the mother of all motor failures: a seizure. A close cousin is the piston burning a hole through it’s top. Molten...
by Jeff Goin | Apr 22, 2019 | 23: Motor & Propeller, Mx: Motor
Testing the difference in running temperature between car gas and av gas There’s a lot of dispute as to which is better to run in your paramotor, avgas or mogas (as in motorcar), especially with the higher ethanol content of mogas. But one claim is significant:...
by Jeff Goin | Apr 7, 2014 | 22: Aerodynamics, 23: Motor & Propeller, Log: Paramotor-Ultralight, Reviews: Paramotors
Florida’s relentless weather perfection lured us aloft again. I got to try Parajet’s newest offering, a Thor 250, water cooled, behemoth with thrust galore. It’s ideally suited for trikes or competition pilots powering their tiny little steeds to...
by Jeff Goin | Nov 17, 2010 | 23: Motor & Propeller
Download the Prop Speed Spreadsheet to quicken your calculations. What’s the right prop for your paramotor? As you can imagine, it’s not a simple answer, but here are some criteria on which to choose. First some basics about props and engines to get you...
