fuzzybabybunny

I've got the ROS 125 motor and had 3 flights today. I've been having engine-outs and blips in power recently at launch but since I'm a new pilot I figure that maybe I'm not warming up the engine enough before flight. I have no issues during normal flight. Since it takes about 10 seconds at full throttle for me to climb to a safe height at launch, I figure that a reasonable warm-up technique will be to stand on the ground and run the motor at full throttle at 10 seconds before each launch. - I let the engine idle without a prop for 10 minutes as I got other stuff ready. - Turned the engine off to put on the prop. - Right before the first flight, I go full throttle while on the ground but at about 5 seconds it goes out and I have to restart it. I go full throttle again and it does the full 10 seconds without issue and the climb out has no issues. - Landed and turned off the engine for about 10 minutes. - Warmed up engine at full throttle for the second flight. There must have been a bubble or something because after about 4 seconds the engine power died momentary and then quickly went back up. - The same blip occurred while climbing, giving me a bit of a scare. - Landed and turned off the motor for 15 minutes. - Filled the fuel tank to half from quarter full. - Did the same warm up on the ground and this time the motor died twice before it could do the full 10-seconds at full throttle. - During climb out there was another sudden loss in power but it seemed to last a bit longer than last time. I was already thinking about my glide down but the engine thankfully kicked back to life.

I'm talking about doing this with the prop NOT installed. There's zero chance of prop strike because the prop is still sitting in the boot of my car.

I know that the mounting points are different, but I don't see any technical reason why a harness can't be made with two different mounting points, one for PG and another for PPG. My dream harness: Super lightweight like the Gin Yeti. Modular like the Kortel Kuik II (you can add a backpack, a cocoon, an airbag, etc) Use it by itself for PG. Mount it to a motor and frame and use it for PPG. Pair this with an ultralight wing that can do both PPG and PG and you've got a really serious setup for travel and fly. Does something like this exist?

I've asked my instructor this but I wasn't able to get a clear answer. For non-reflex wings, what's the difference between and PPG wing and a PG wing? I have a Gin Pegasus which is basically the Gin Bolero but with trimmers. I use my Pegasus for BOTH PPG and PG. It works fine for both. - My paramotor allows the use of speedbar anyway, so are trimmers redundant and is using both at the same time unsafe? - My wing has a second hole for hooking through the carabiners on a paramotor that's slightly higher than the normal PG carabiner hole. - Besides trimmers, how else does a PPG wing differ from a PG wing? - If I fly a normal PG wing on a paramotor with speedbar, what am I going to feel differently?

I was thinking about turning on the engine without the prop just to get the engine to turn on. I'm still getting the hang of properly priming the motor - it's usually not primed enough or primed too much and I have to tip the machine over so the excess fuel dumps into the air filter box. I also have to press on my membrane carb to get rid of air bubbles? All of this would be difficult while it's on my back. So I figured I could just get it primed and turned on (without even pressing on the throttle), and then shut it off immediately. Then, while on my back, I can do the normal warm up routine.

I'm on the nzairspace website and there's an "MZ" airspace that covers a lot of NZ but I can't find anything about it in the NZ Airspace manual. It's not Military because that's MOA. http://i.imgur.com/M84X705.png

So this occurred to me - wouldn't it be safer and just as effective to just start the motor on the ground *without* the prop installed? When I take out my kit I have to put the prop on anyway. Seems to me that if the aim is simply to get the engine primed and started for a small warmup and to clear fuel line bubbles, starting the engine on the ground with the prop not installed would solve a lot of problems.

I JUST got my PPG license! The New Zealand requirements are 25 flights, one cross-country flight of at least 30km, simulate an engine-out, and restart an engine mid-flight. Here are my thoughts, many of which never, ever occurred to me before taking this course. - Before getting into PPG, I vastly underestimated the room required for a safe launch and landing. We found a sports field that measures 1000 ft x 500 ft ( ~333m x 166m ) with ample farmland on two ends of the field, and at this point this is a comfortable size for me to launch from. The reason for such a large size is due to safety in case there is an engine-out at the beginning of flight, when your feet have left the ground and you're trying to climb and gain height. I've had 3 engine-outs already on two different machines in just 25 flights. On all three I was thankful to have that extra length of field to continue to just fly straight-ish and do a good landing. On ALL three engine-outs, I had NOT gained enough height to do a 360 and land back into the wind. If I didn't have that extra runway, at most I could have done a 90 degree turn and landed crosswind, or done a 180 degree turn and smacked downwind, or done a 180 degree turn and smacked sideways as I try to finish my 360. TIP: find a massive field to launch from, and just as important, make sure that there are safe bail-out spots immediately beyond the field. A field wrapped on two sides by power lines and trees on the other two sides isn't a good option. - A large field also gives you different options for landing and launching should the wind change from under you. The wind might be coming from the north on launch, but it may have changed to west when you want to land. Is your field fat enough and free of obstructions to allow for this change? If your field is narrow with power lines on the east and west you're going to have a plan B. - As above, if you're launching and landing from the same place, remember that conditions can change during your flight. A break in fog doesn't necessarily mean you can launch because the fog could roll in during your flight and you'll just come back to a landing site with zero visibility. - Before launching, have a plan for *exactly* what you will do and where you will fly to should your engine go out during your climbing phase. As in, before launch, stop everything - just stop - stand there, look around, and devote a good amount of time to rehearse in your head where you will immediately turn to and land if your engine quits. On one of my engine-outs I got caught off-guard (because I didn't have a plan and was so focused on launching) and got target-fixated on the power lines in front of me as I continued to fly straight but down. My instructor snapped me out of it by telling me which direction to turn to land in a safe spot. - Get everything on your person sorted before going off for a flight, because it's very hard to rummage around for stuff and adjust things when you're already in flight. The harness makes reaching some things difficult or impossible, and grabbing around for stuff increases the risk of that thing being accidentally dropped and sent right into the prop, destroying it and resulting in a forced landing somewhere. I was burning up on the ground, so I opened my jacket's pit zips. During my 40km flight I could no longer zip up my pit zips so I froze and shivered madly for half the flight. - Anything that you have should have a rope or string tethering it to yourself, but the tether should not be long enough that the object can reach the prop should it drop. - Carefully consider if any jacket hoods could blow back into the prop. - Give the motor a good warm-up on your back right before launch. Like 10 seconds of full throttle. On my first ever unsupervised launch I was warming up on the ground and the motor went out after 8 seconds of full throttle. I feel like it would have *absolutely* been an engine-out during climb otherwise. - During flight always be reading the wind and looking for places to land and directions of approach should your engine quit. Have a mental buffer of landing spots you've flown past so if you're flying against the wind you can do a 180 and quickly reach the landing spot downwind that you had previously passed. - Practice grabbing around for stuff on the ground and in the air. By stuff I mean the compression release and pull starter (for restarting the engine in midair), the fuel line and primer bulb (for killing the engine should the kill switch not work or the throttle gets stuck), and your straps (in case of water landing - I've got at least SIX straps to unbuckle and right before a water landing is not the time to hope you've unbuckled all of them). - Practice looking for power lines and poles. Just stay away from poles. My instructor had a guy who landed in a line because he looked at a pole and couldn't see the line... until he came down for a landing and *then* saw it. Poles - even if they look like there's no wire, just stay away. - Wear gloves with wind protection. I got cheap hardware store gloves with leather underside but mesh everywhere else and it gets cold. Really cold. - I wore normal tennis shoes. Well, the field I was in was slightly wet and soaked my shoes. My feet then froze in midair. My instructor had warm waterproof boots. - Because we're often launching and landing in nil / light wind, having a good wing that inflates easily is really, really, really important. My instructor was flying an old wing (three years old) that works totally fine for coastal soaring, but is a total pain to launch in light winds. During our cross country flight he decided to land in a sports field with the intention of having me do another launch, but he landed, realized there was no wind, and I taxied in the air for the next 20 minutes (freezing in my wet shoes, mesh gloves, and opened pit zips) as I watched him struggle over and over to get back up in nil wind with his old wing and with the help of two children nearby. After I blended my lines and destroyed my prop on a previous day, I used his setup and could tell the night and day difference between his old wing and my newish wing.

I'm a new PG and PPG pilot and as my flight numbers go up I want to have an easy way to track and log my flights online. Right now I fill in a form manually and it's a pain in the butt. I would much rather download an app (Android) that doubles as both a flight computer and a flight logger. I've tried XCSoar but I find it VERY confusing and not intuitive. Plus it doesn't seem to do things like overlay air spaces over GoogleMaps satellite view, etc. When I'm flying I find that I'm switching between XCSoar and Googlemaps all the time. So, anything out there that is both a flight computer and a logger?

I'm a little confused on this. When I Google the ROS125 engine the PAP125 always seems to come up. Not sure which is which.

Woohoo! I'm sitting here on the beach waiting for my instructor to finish a cross country flight with another student that I was also supposed to be on. I was the first to launch. Nil wind, so I was in forward launch position holding the A risers in each hand around shoulder level. Instructor told me to warm up the engine so I started squeezing the throttle. Some experts here have probably already caught the error... Anyway, an entire group of C lines got sucked back, through the netting, and into the prop. Three blended C lines and one blended B line. The dyneema lines cut deeply into the wooden prop like a knife. Now, what I *should* have done, because I was in the forward launch position (which we rarely do because here in NZ we almost always need to reverse launch), was to turn to my side to warm up the engine so that nothing could get sucked into it. So I reckon that's about $600 USD worth of damage right there and some extended ground time, waiting for replacement parts to be delivered, etc. But overall I'm glad I had this learning experience in the environment of a class. I reckon I would have *definitely* done it on my own after I got my license. So far, first engine-out on eighth flight, parablend on tenth flight. So moral of the story - when in forward launch position and you need to warm up the engine before launch, turn to the side to warm up!!! Do not face forward to warm up!

I guess the part that I get stuck on is this: When an engine runs lean, it means that there is less fuel, *not* that there is more oxygen. When I go to adjust a carb for leanness/richness, I adjust the screws that control the flow of fuel. I don't adjust anything that has to do with the flow of air. So it would be something like this for a "normal" mixture: 50 mol CH4 + 100 mol O2 -> combustion -> 100 mol H2O + 50 mol CO2 + 5000 kJ heat (or whatever) And for a lean mixture: 40 mol CH4 + 100 mol O2 -> combustion -> 80 mol H2O + 40 mol CO2 + 40 mol O2 + (something less than 5000) kJ heat So I would think that the "something less than 5000 kj" would mean that it should run cooler since there is simply less moles of fuel being burned. The amount of O2 in the combustion chamber is the same because the carb adjustments only restrict the moles of fuel getting into it. In a lean mixture there is more complete combustion of the fuel, but there is also less fuel. So is it fair to say that despite there being more fuel in a rich mixture, MORE fuel is being burned in a lean mixture anyway? So running an engine slightly lean will produce more power than an engine running slighting rich? And because a rich mixture burns less fuel and has more evaporative effects than the lean mixture, the engine runs cooler? I get that a stoichiometric mixture in real life won't have complete combustion and that lots of other things will be made from incomplete combustion and all the other elements in air besides O2 when running rich. And there's more excess fuel being evaporated so the heat of evaporation factor is more.

Yeah, I understand that in rich conditions the excess fuel can evaporate, cooling the engine down. To me this is a little weird because I wouldn't think that such a little bit of evaporation would actually effect that much... But it's the lean-running condition that confuses me. Like I said in the OP, the chemical formula is pretty straightforward.

So I've got a question on my exam that's going to be something like "what's PTE?" For me this is a pretty general question because there are a lot of forces at work and I'm trying to understand them all. Let me know if I've got this right: On my machine, a ROS 125, the prop spins clockwise if viewed from the back. 1. When accelerating the prop, because the prop is going CW, myself and the cage will want to spin CCW. This would lift my right riser and pull down on my left riser, which would make my wing want to do a left banked turn (the roll axis). 2. If the prop is angled upwards, the right half of the prop will produce more thrust than the left half due to P-Factor / Assymteric Blade Effect. This makes me and the cage want to yaw to the left. I've heard this effect is small though? 3. Precession would cause me to want to yaw to the right because the prop is spinning CW. I don't know how this interacts with #2 or if it would cancel out? 4. Prop Wash is not an effect on paramotors since the prop is behind us and there's no vertical tail for the prop wash to hit, as there is in airplanes. So.... lets of weird stuff going on. The worse effect of PTE is really a combination of all these effects plus the pendulum nature of paragliders. The PTEffects cause me to yaw to the left, twist the risers, and the thrust, being directed to the left and no longer aligned with the axis of the wing's travel, causes the wing to go into a right bank due to pendulum effect. So my body is physically pointed left but I feel like I'm in a right bank and my risers are twisted (and there is some twist energy + pendulum energy stored up as well so if I completely let go of the throttle the glider and my body would then swing in opposite directions as the stored up energy gets released). The best thing is to lay off throttle in a measured way and allow the glider to straighten itself out. Am I missing anything else concerning Propeller Torque Effects?

So the general explanation for why a lean fuel mixture produces more heat and can lead to an engine seizure is that it's the same as if you took a fire in a fireplace and fanned air into it. With the added air the temperature of the fire goes up. To me this doesn't quite make sense around the subject of engines. If you have a general combustion formula: CH4 + 2O2 -> combustion -> 2H2O + CO2 + 100 kJ heat (or whatever) If you simply add more O2 without increasing fuel (CH4) the amount of energy and heat released should still be the same: CH4 + 48O2 -> combustion -> 2H2O + CO2 + 46O2 + 100 kJ heat The only way for it to increase heat is if more fuel was burned. And this is what I don't understand about lean-running engines producing more heat. When you tune the carb to run lean, you're restricting the amount of fuel that gets into the combustion chamber, right? So less fuel in the combustion chamber should mean less heat is produced, right? The reason the fire in the fireplace gets hotter when you fan more air is because more fuel is being burned in, say, 1 second than if there wasn't air being fanned onto it. All that extra fuel (wood) is just laying there in the fire itself. But in the case of engines the combustion chamber only has a set amount of fuel, whatever amount the carb is set to deliver.

Oh, I'd actually like to add that doing PG helped me get used to what a wing *should* do. Basically, a lot of problems can be overcome by simply laying off the brakes a bit and letting the glider fly by itself. It'll sort itself out if it's a beginner wing. If there's a collapse and it doesn't sort itself out immediately, weight-shift to the side with more support and simply do a gentle pump of the deflated side's brake to re-inflate. Happens during ground handling all the time as well. But basically just let the wing fly naturally and I'm used to how my glider should fly. Now add the motor. I've been reading up and watching videos on all the weird twists that the motor can create, the most major being yawing the pilot towards the left but sending the glider into a right bank since the bottom of the pendulum (pilot) is now being thrust to the left, so people react by pulling hard on the left brake and doing nothing to the throttle, which makes everything worse. I've had some weird things happen doing flight and my first reaction is always to lay off the throttle and let the glider fly, because I trust my glider and know that it'll fly happily on its own if given the chance. I guess it has a lot to do with the motor unit still feeling like a foreign object. If anything weird starts happening, I immediately cut out the foreign object and revert back to what I'm used to - free flight.

I came from PG with about 80 flights, 20 flight hours, and maybe a total of 25 hours of ground handling in terrain ranging from flat grass to kiting up sand dunes and all wind conditions ranging from nil to "you're an idiot for even trying to ground handle so let me drag you clear across the footie field with people watching and twist your ankle in the process for good measure. You idiot." All I can say is that I'm really thankful for the PG experience. Maybe I'm slow, but getting used to just flying and ground handling PG took some solid time and initially my brain was overloaded - steering the glider while running along the ground, timing flares, launching, figure eights, figuring out how much brake pull is needed for tight turns, flat turns, flares, etc. When I started my PPG I didn't need to worry about any of that, but I was *still* mentally overloaded because now I've got this huge heavy spinning death fan on my back, roaring in my ear, pushing me around, preventing me from easily shuffling under the wing, and I've got so much extra crap in my throttle hand - the brake, the throttle, and the kill switch (and a riser if doing a forward launch). And I've gotta lean backwards while still running forwards, lol. So I think that it's a lot easier coming from PG. It's still not easy, but I can't imagine starting on a motor with next to zero PG flights, unless maybe I already had 100 hours of ground handling or something. The only PG habits I had to not do were: - don't lean forward and torpedo on a launch - be more "textbook" with all maneuvers and getting the wing up and kiting. You can get away with an awful lot of sloppy shit when you're only doing PG and wearing a 1kg harness - things change dramatically when you've got a 20+kg motor on your back!

Man, I would love to have a unifying engine. Get an inflatable raft and mount the paramotor to the back and make it into an airboat / swamp runner. Then get it off the boat, deflate everything, and go flying. After flying collapse the frame and chuck the motor into a motorbike and ride back home. That kinda thing.

As I understand it, gasoline has an energy density of 36 MJ/L. Current batteries do 2 MJ/L (gasoline has 18x the density). Bleeding edge batteries have 4 MJ/L (gasoline has 9x the density). But let's not forget that electric motors are inherently more efficient than Internal Combustion Engines. ICE two-strokes are like... 30%? And they're fundamentally limited in efficiency by the Carnot Cycle. Electric motors are 95%. So - with current batteries with an energy density of 2 MJ/L, a 10L battery pack should be able to do the same amount of work as a ~2L tank of gasoline. A 10L battery with 4 MJ/L energy density should be able to do the same amount of work as a ~4L tank of gasoline. Now that's getting kinda close? But 10L of batteries would be quite a bit heavier than 2L / 4L of petrol... and 10L of empty batteries will be infinitely heavier than zero liters of petrol at the end of the flight

I'm wondering how standardized the equipment of PPG are. Are there industry standards for replacement parts, mounting points, etc, or is it all pretty proprietary/custom to the manufacturer? My guess: Engine parts are standardized? Since they're just regular 2-strokes? What about, say, replacement belts? Carburetors and clutch units should be standardized I'd imagine. Engine mounting points? Can you take any engine and mount it on any frame?

I'm not trying to abandon this place or anything, haha. You guys have been very helpful and welcoming. Just wondering if there are any additional active/popular online forum resources for PPG? I know that paraglidingforum has a PPG section. Is that basically it? Seems like PPG is a pretty small community all things considered - certainly smaller than, say, SCUBA diving

Bummer. So I guess that prop noise is like 90% of the noise of any PPG unit then?

Why do I have to put my finger into the depression and squeeze the bulb to get rid of the fuel line bubbles? What does that depression do, versus not putting my finger in there and just squeezing the bulb by itself?

Just how much quieter are these electric paramotors? You've still got the noise from the prop which isn't going away. Does this mean you can fly without hearing protection?

Oh yeah, and I should mention that I got an engine-out on just my eighth launch, and it was AWESOME. I climbed to maybe 30 feet and *bloop* no more power, a good deal of pendulum, and a lot of confusion - I thought that I had accidentally pressed the kill switch but I'm convinced I didn't. I then did a lot of stupid things immediately afterwards: - I instinctively put on some brakes - I turned to the right a little bit (don't know why - I'm an idiot) and that meant going a little crosswind and also directly into a wind shadow from a line of trees. - I realized I was an idiot and let off the brakes to build up speed for the flare. I knew the wind was light so I was hoping any turbulence from the wind shadow wouldn't collapse me. - My slow speed only allowed a partial flare and I still came down a bit crosswind and slid out. I'm really glad I had that experience of an engine-out during instruction. We had the chance to reflect on everything - my weird reactions, my improperly short warm-up of the engine (I didn't push it to full throttle while still on the ground because I'm still scared the thrust will knock me off my feet), and all the planning behind *why* I took off where I did. The instructor chose that spot because if there was an immediate engine-out there would be plenty of safe, exposed landing options within 100 ft of where my feet would have left the ground. And it hammered home to me just how many layers of paranoia I need to have when planning every. single. aspect. of my flight path, from feet on the ground at launch to after my wing is finally back on the ground and killed on landing. This is a new way of thinking for me, having come from PG. With PG, at least ridge soaring along the coast, you will almost never have lift and then instantly ZERO lift. So the planning isn't as crucial. It's a bit ironic that with PPG, in which you can generate your own lift at will, you have to also plan for instantly losing all lift, lol.