
273 Simms
Big puffy cumulus over the plains and wind blown cumulus in the foothills. I got to the field right at 7:00pm and sunset was at 8:00. It was blowing 12 mph from the south west swinging all the way over to north west and back. Marek and I kited for a bit and Tracy even took a hand at kiting the sting. At 7:20 the sun set behind the foothills and we knew there was going to be a short window of good air. As I was getting the helium tank out some cool air flowed in without a breath of wind…I popped a black balloon and sure enough it was smooth and dead calm up at least 300 feet.
Marek got up first and with a little manual assist from Tracy to get the buggy rolling on the super soft soil I followed. The wind had started to pick up from the west a so I was forced to take off toward the wires and turn as soon as possible. The run out was a bit long and I noticed some bad friction on the right side but it didn’t prevent a clean right hand turn over Hwy 285. I followed around till I was heading toward the high school and took a minute to get some altitude and take the twist out of the right brake pulley. The air was nice and smooth at first but as I got to 6000 feet there were the beginnings of not bumpy but mixing air.
The Thumper was spinning at 3650 and I noticed that there is a little lurch when I goose it from idle. Probably getting a little belt slap as well. It sure sounded sweet when I backed off the throttle and…at idle I could not hear anything at all. For some reason I chose not to use the Emoitic plugs and IPOD and enjoyed the comfort of standard foam plugs. I’ve been missing allot by filling my head with music. It pays to be able to hear the motor and it would be great to flip back the ear cups when I’m descending or maybe even at level flight!
Over the High School I did some slow turns and worked on slight changes in the throttle. It would be nice if I could find a simple way to increase the throttle travel but I’m finally getting used to it. It helps to use the two little fingers on the throttle and the bigger two on the brake.
After climbing to 6200 I did slow descending spirals over Soccer field and and made an approach toward the truck. The air had “turned” down low…there were areas of sink and lift making it difficult to make a long low approach so I did a fly by at 40 feet and went around again. Turning clockwise at full power I was really disappointed with the climb but it was as much sinking air as lack of power. Hopefully a new set of blades that are two inches longer will be enough improvement to make me happy. Maybe I’ll even be able to get a little bank on a full power turn. 
The second approach was smoother and I set down right by the truck. Tracy hung around while we packed up and promised to e-mail some photos if he got anything good. Short but sweet….Just what I needed to kill the funk after spending the last 4 hour stretch alone at the store.
Explanation of two stroke power by Mike Noland
Note to nubes about thrust ‘tests:
Two stroke engines are about managing very rapidly oscillating pressure pulses. The pulses are managed by intake tract configuration, intake valving(usually by flexible reeds), shape, size, angle, and timing (position and angles of edges) of ports, ignition timing, and timing of exhaust pressure pulses reflected back by expansion chambers.
When intake and exhaust pulses are timed to push the most fuel/air mix into the cylinder as the ports close, you get the most power. The speed of the pulses is affected by rpm; it’s not possible to make the engine charge at maximum efficiency over its whole rpm range.
Tuners are left with some choices. Motors can be tuned to produce a high power number across a narrow rpm range, or lower number across a much wider range. Engine makers who tune for peak power, like a motocross bike, like to compare their peak numbers to FBs, because FBs are tuned to produce a lower number across a wide range, like a street motorcycle or a conventional airplane engine.
The engines tuned for peak power work best for flying styles that resemble motocross racing; if you do a lot of acro such that your throttle is always either wide open or idling, you’ll be happiest with something tuned for a peak power number. The engines tuned for useful power across a wide range of rpm are better for level cruising. They easily hold constant rpm over a wide range, which means you don’t have to pay close attention in order to cruise along in level flight with your engine running smoothly and happily.
Engines tuned for peak power very much want to run in their narrow zone of efficiency, which is often at a power level too high for level flight. If you run them where they are happy, they climb. If you insist they cruise level, they are harder to hold constant, and because they are out of their zone of harmonized intake pulsation, port timing, and exhaust pulsation, they run raggedly and blow a lot of unburned fuel right through.
A while ago, a friend who had only flown motors tuned for peak power asked to fly my FB Solo 210. He ran it up on the ground, and was concerned that it might not make enough power. When he launched it, he ran 20-25% farther than he did on his peak-tuned motor. His climb rate was not as good as it was on his peak-tuned machine. Not good so far.
His attitude dramatically changed once he leveled off and went for a cruise. His radio chatter was all about how incredibly smooth, smooth, smooth the 750-hour-old FB was. He went on and on about how easy and relaxing it was to fly. It appeared to him to be more powerful flying level than his peak motor, and at those low rpm levels, it probably was. He landed smiling, and ordered a FB Simo the following Monday.
No matter what your salesman tells you, your two-stroke can’t have both killer power and Cadillac cruise. If you want a motor that runs like a car over a wide range, cruising comfortably and economically over long distances, the peak power guys will out-climb you. If you want the thrust king, it won’t be as pleasant to fly on long cross-country trips. Those are two-stroke facts of life.
Fly high,
Mike Nowland
Flight 272 Simms
Flight 271 Simms
No Fly Day in April
Pros and Cons of the Thumper
The biggest downside to going 4 stroke is the lack of fun things to do while not flying. Having spent the last 4 years immersed in this sport, I was comfortable with all the the wonderful little things that are a normal part of a PPG pilots life. The nights spent in the garage replacing compression springs or driving to the airport after dinner to pick up AV Gas. If I wasn’t searching the Internet for the best buy on Castrol TTS, I was waiting for the UPS man to deliver a 160 dollar starter sprocket. It seemed like I was either working on the maching or flying it.
For every minute in the air there was an equal or greater amount of time occupied with the care and feeding of my 2 stroke paramotor. If it was blowing…no problem, I have a pull starter to rebuild.
These days… things are different, because the heart of the “Thumper” is a Briggs & Stratton, twin V, 4 stroke motor. Thousands of these motors are built every year and the economy of scale makes it possible to produce a very affordable motor with excellent manufacturing tolerances and a beautiful fit and finish. They are designed to run 10,000 hours at peak horsepower, so it’s not unreasonable to expect to fly hundreds of hours with nothing more than an annual check-up and oil change. When necessary, parts and expert service are readily available at the local lawnmower repair. Gone are countless hours tinkering with the machine. No mixing fuel, exotic tools or translating owners manuals. Now ,when it’s too windy to fly, the best I can do is wish for better air. You still have to be ready for a “motor out” and have an emergency landing site within the glide slope but the reliability of this motor instills a confidence that allows for flights that would not have attempted before.
Flight 270 Simms
The wind speed chart shows moderately high & gusty winds from the south south east. Sunset was at 7:00pm.
Flight 269 Good Air at last Simms

I’m getting used to the long take off but I was a little surprised by the way I floated at 10 feet for a while before it finally started to climb. I’ve been letting the buggy build enough speed to take off without brakes but it might be a good idea to ad some brake and see if it improves the climb.
So…I ventured away from the home field and went over to Bear Creek Park for a look see. I should have tested the foot steering but I think I’ll wait until I get some kind of cruise control to free up my hands. Same for the trimmers…next time I get into some decent air the trimmers are going out!
The biggest thing to get used to is the slow run up the power band or maybe it’s just flying with less power. Touch and goes are tricky because you have to be powering up for the climb-out before you touch down. Another thing is I don’t have the power to do any hard banking turns, it might be better with the trimmers out…I’ll have to wait for the next flight.
Next time the wind is coming out of the east I’m going to try the Eden III 28m…if it climbs slow at least I’ll have plenty of room to work with.
267 & 268 Simms


Simms … Two ten minute flights. Equipment was without issue. 65 degrees.
Climb is good but the takeoff was much longer. Reading last weeks log,… I notice all the same things. I’m still tentative on the wing and missing the old throttle.
The first flight, I climbed to 400 feet and landed. The run out was very long with the trimmers out but the wing came up very fast. Very ratty air all the way to the ground. I was more than happy to use the entire runway and make a long straight approach. There were puffs I flew threw that would slow me down and change the glide. Not dangerous but not the best place to be making tight turns either.
By the time I had walked the entire width of the field the wind was starting to mellow. A 15 year old kid was tagging along…nice kid I’ll try to give him a little more attention next time. 🙂
Second flight came 10 minutes after the sun had set behind the foothill. I kept it short and enjoyed a little better air. Trimmers in, wing came up slower, but takeoff was quicker. Climb out was sluggish at first but came up nicely. Landing was perfect …power on dragged the back wheels for a long time before I felt the front wheel touch.
Getting used to the Thumper/Powerplay Sting… It’s bigger, heaver, and slower to react. I miss the Simo’s snap but the trade off’s of the 4 stroke are still worth investigating. The place where it will really shine are long x-country flights. And…I have not had a good opportunity to do that this year. Guess I’ll have to get up early and put on my Michelin Suit to do it right.









You must be logged in to post a comment.