Blackburn Mark

Not sure how you are measuring but that does not look like 30 degrees... Looks more like 10~15... looks reasonable to my eyes but i like to fly my v2 more upright, less comfy but more efficient and safer. I drilled another set of holes to get what i wanted... Not advising you do the same, just letting you know what i did Those are high mount bars... Not a lot of room to drill further back and less of an effect even if you did. The weights may be misleading a bit, your leg weight would have more overhang so i would assume a couple more degrees in the positive direction once "you" are strapped in. If i saw that flying around at that angle, i doubt my mind would register is as anything particularly unusual.

FULLTEXT01.pdf (diva-portal.org) This seems to somewhat corelate with your basic premise... Not sure if you have read it or the person giving you information has read it (I suspect so) It is dry, complex and boring so I have yet to parse (if I ever do) the efficiency statements that at first glance, "seem" to contradict contemporary thoughts and theories. So in inference, I suspect, to our untrained eyes, that (for example) the statement that a "three blade propeller" is more "efficient" is in reference to a confined scope (EG: combined static and cruise) We are pretty much a single speed (very slow) machine so the gap between static and cruse is small in comparison to the Pipistrel in this paper.

That doesn't change the facts. Energy is being burned to sustain that frame torque... The propeller is like a slipping clutch holding a rock off the floor. They must be hiding gold in there! ........? If you do build another, and you want to attempt to out perform the "current trend", it might be worth you getting to the bottom of the conundrum as you seem to be either dismissing or trivializing an aria of great importance… That pesky flight time

Are you sure I don't understand? When you say "more efficient" in this particular context, are you sure you are not conflating two entirely different regimes? More frame torque = more lost energy, there is no escape from that... You cant get something for nothing and frame torque is not nothing! What has that got to do with nub of our disagreement? A redrive can be fitted to allow for any ratio in synchronizing propeller efficiency and motor efficiency. Typical paramotor engines = £2500 mad M50 40kv = £1100 retail, £800 of molicel P42A li-ion batteries = 4000kwh (ish) That's £600 to cover the ESC I will tentatively concede that the price point "may" be comparable ish with IC That depends on how you look at it... More frame torque is indicative of a loss in efficiency just like an increase in resistance when pushing a trolley if a bearing sticks... its lost some efficiency. For some reason, people cant get their head around that

Less efficient than a simple two blade Four wig tips. less efficient unless you go for the full 140cm ducted fan... That would make it quite bulky and hard/expensive to make

I have absolutely no idea where you are getting the idea that i think I am claiming to get more out than I put in... Can you quote where I have said this please. You have wasted quite some ink on debunking and argument I have not made. That's open to interpretation and considering that he says "petrol ppg have never really been interested in noise reduction or efficiency" its reasonable of me to infer that he meant EPPG Now you are contradicting what you think your man with the plan is saying. Which one is it? This would be a whole lot easer if you just explained where you think the "frame" torque originates.... Or more precisely, what is acting in opposition to the propeller travel in order to cause the paramotor frame to react in an equal and opposite fashion? I'm saying it is all drag which means the additional pitch and frame torque on the SP140 you mention is an indicator that the designer may have got his priorities wrong for a motor that already has a very short flight time. I suspect its more to do with deleting the need of a redrive (or higher diameter motor) and attempting to butter over that by pretending it is a deliberate design feature for lowering noise (Sales spin) If I am correct (you haven't demonstrated my error yet) , $7320 with such a small parts count and they cut corners at the expense of efficiency, its a bad look for a machine that needs every inch I had a look at Open PPG... They also sell a painfully inefficient multi propeller design unit. At least they are moving in the right direction

That's a shame, he doesn't seem to answer the question you asked. Instead he seems to be speaking to "relative" efficiency in regards to the given diameter and attainable thrust: EG: three blades can deliver more thrust at 140cm diameter than a two blade... He says nothing about the cost in requiring extra torque to do that. Two blade props are more efficient than three in regards to the "torque to thrust" efficiency that we are grappling with. Suddenly I find myself distrusting the man, he is over-egging his sales pitch to the point of giving himself away with this statement! An absurd thing to say. ....? It wouldn't be 100% efficient if there is any drag at all! Induced drag (lift drag) increases with pitch. Induced drag reduces with aspect ratio. Three blades have one more tip to shed an induced drag vortex. For all I know, that could be to do with the inverse torque curve of electric (in comparison to IC) in the attempt to avoid the need for a reduction drive... It certainly sounds like it. Pretending that its a deliberate attempt to be quiet would be a posh way of hiding that higher pitch = less efficiency and a redrive (or broader motor) + less pitch would give more flight time... On a heavily priced paramotor, I would expect a little more focus on the "real" limitations and a little less on the ancillary concerns. You will have to excuse my skepticism, keeps me warm at nigh

If that "7.8ft lbs" is to fight drag, that would be 7.8ft lbs of frame torque... At 100% efficiency, that 7.8ft lbs would not be lost in drag and would be added to our thrust instead leaving us with no frame torque. A 100% efficient propeller would ONLY transfers 100% of the input torque, nothing more. Furthermore, a 100% efficient propeller would have zero drag, turning 100% of that torque into perpendicular thrust. Where would the frame torque reaction be coming from? A 100% efficient prop would act more like a 90 degree bevel gear with a road wheel on it pushing us forward, all the torque actions and reactions would be contained within the assemblies frame of reference putting 100% of the output torque into forward thrust only... No frame torque. Removing the drag would place all the force at 90 degrees to the output shaft... At 100% efficiency, there is nothing there to cause frame torque... Nothing there acting in opposition to the blades travel (Newtons third law ) I must admit that I am still scratching my head looking for stray lift vectors... Cant see any at the moment.

That makes no sense to me. A 100% efficient propeller would have zero frame torque besides the momentary "spin up" torque. All things being equal, 100% of frame torque is caused by blade drag, mainly "induced" seconded by "form drag" followed by "skin drag" (Think this is true of subsonic) Increasing pitch increases the former and reduces the latter two as the speed falls, all of them acting in opposition to the blades travel (Action) What other possible action in "basic physics" could invisibly cause this particular frame "reaction"? Cool, maybe he can throw some light

An Atom 80 + DC motor, battery pack charge gear and motor driver might weigh as much as a Moster 185 and you wouldn't be ringing the Mosters neck In fact, unless you are a heavy pilot, the Atom might be greats as it is.

You have us speaking to different points. I did ask you if you meant output torque or frame torque, you fail to clarify so i assumed you meant 30% more frame torque. .....? Now you "are" talking about frame torque...An increase in frame torque = a decrease in efficiency, it cant be anything other than an "increase" in blade drag (THATS the "dead loss" I was talking about) What do you think causes frame torque? Is that an educated guess or have you something to link to that shows it to be true? I would much appreciate a look at that evidence as it contradicts my "An increase in frame torque = a decrease in efficiency" claim above.

DTpropeller - Carbon and wooden propellers for paramotor and paramotor trikes I have not tried one yet, they seem to offer some fancy tipped props. Gyrocopters are pretty noisy if my memory serves Lets hope we get an unaffiliated Youtuber giving us some real world feedback on what its like to live with one. That would make me a little nervous but fingers crossed. 100hrs was a bit low, 1000hrs is quite optimistic without any practical evidence. The potential is there especially for motors... Not sure yet about controllers though. All torque reaction is wasted energy so that 30% increase in induced blade drag is a dead loss, like i said, higher pitch seems to come at a cost. Its not something I would do on a machine that needs every efficiency gain it can get its hands on. Frames diameters can be made to fit larger props. Airconception have a 160 frame You have lost me here... Prop diameter has the single largest effect on efficiency... Electic, IC or even human powered At the expense of efficiency. I don't know the fundamental's in detail... It seems there is a "sweet spot" between diameter, pitch, chord, profile and speed, its not trivial.... Think best L/D on a sailplane wing. With the diameter being the strongest influence (all thing being equal) Think aspect ratio on a sailplane. I suspect you may be focusing on one item (noise) and neglecting the effects of doing so. Electric has some problems to solve and noise is NOT one of them

Ok... Ill play 50 two hour flights, I get the feeling Mosters do quite a bit better than that... Baileys, even more so... That's if we compare a mosfet referb with a head/piston swap, not an unfair comparison, both well and truly ground you and cost hard cash An over-engineered ESP may last for decades of hammering but my experience with off the shelf ESP's is hit and miss even when I have vastly under run them, they can die. Its hard to speak to the problem with such a small sample size but controller issues are often "hot" topics when i have followed experiments with electric flight. Ill grant you that there will be less need for tinkering and no need to run the classic bead through a cracked Moster exhaust but that can be done between flights That would take some doing... I would think higher pitch/broader chord would give away some aerodynamic efficiency and static thrust for a given diameter. These are things that could be done with an ordinary IC powered paramotor but we don't see it... why is that? The Atom 80 seems way quieter than its prop. I suspect a lot of paramotor prop noise is caused by it cutting through all the turbulent air caused by the frame, head legs etc... Common with pushers apparently. Torque would only increase as a fraction of and in proportion to the loss of efficiency (not much in terms of frame torque but unlikely to be insignificant in terms of flight time)... Or are you talking about the motors need for "more torque"? If i had a brushless with enough torque to spin a high pitch prop, I would slap a 160cm two blade on it instead... Probably be quite (ish), more efficient and give another 10% static thrust

That's a list of ancillary properties and some of those are a stretch. Mosfets don't last forever and are a pretty nasty job to replace, The prop is never going to allow us to fly without ear protection anyway, maintenance I will tentatively grant (depends on how hard you are pushing those mosfets) Vibration (or lack of) would be a winner, not sure where the more "efficient" glide comes from, especially if you have low cogging motor ~ freewheeling prop against a clutch-less IC motor. The big one for me would be the convenience of flicking a switch and being ready to go... Its a small thing but if there is one thing that get on my tits, its prepping for launch... In free-flight, its bad enough but with power you can times that by four... with electric, maybe two or three I don't mean to dampen anyone's enthusiasm too much, I am somewhat responding to the question as to why this thread died... We are waiting for the tech to catch up!

I think Alan was being hyperbolic... Pretty sure 75 mins is still a little short for most of us. I'm sticking with my "two hours plus reserve" before it starts making a dent in the market. The current prices for such items are not much incentive either ($7320) plus the instability of small scale would be a concern for long term after sales care. I'm sure things will improve on the battery front at some point but its pretty brave and risky for manufacturers and buyers at this point

That's the problem, no amount sales spiel is going to butter over that debilitating fact. The whole world is waiting for hover boards and better batteries so its not like the issue isn't front and center for all to see. When batteries have four times the current energy density, are affordable and are safe at that, Joe Average PPG pilot will have a battery option that somewhat competes with his "cranky 2-stroke"... maybe not the four strokes though We are in the "niche" right now... The take-up is very poor and until batteries improve, I cant see that changing. Your phone comparison is more a cost/scale progression. Electric PPG's don't have that problem, all the stars are already lined up but the one. We simply piggyback on the already existent MASSIVE demand for batterie's and motors... Our problem is a technology one and the technology isn't quite there yet and when it is, it will be debilitatingly expensive for the first 5~10 years and that is if Joe Public is allowed to own such batteries.

Ill second that For all the advantages, it just doesn't add up to anything useful for the average pilot at this time. Some of the excitement seems to come from novice or pre-flight "pilots" who get lured by the tech but fail to grasp the practicality of a 20min flight time. (not interested in claims of an hour+ flights if in reality means tickling the throttle in ideal temperature's and conditions... We all know there is OFTEN a gap twixt claim and reality when it comes to the sales blurb) I would say that in practice, the bulk of desire settles into 2 hour flights with plenty of reserve (I get 4hrs + a reasonable reserve and I do use it reasonably often)... No real consideration for what is doing the pushing once airborne, as long as it is reliable and doing its job.... After all, for most, we want to explore the world from the air and shiny gear/posh tech is second to that

Double post

Fingers crossed man! Try and pick out a spot with good parking-easy access if you get options... worth its weight in gold!

That's something to thrash out with any prospective farmers. As for the horses, are you being rhetorical or are you genuinely asking? I don't even bother asking... Not only are you unlikely to get the nod, you would have it hanging over your head that if you farted too loud, one of the crazy fkrs would throw a rider and see you in court! Launches are pretty loud and sudden as far as noise goes... Landing is not so bad or a gentle fly-by (+100m or so) seems ok as long as you are not moving towards them but to my untrained eye, the more expensive a horse looks, the more twitchy they seem to be. I don't like them... But I don't like pissing them off either Having said all that, Paranoob fly's from a field with pony looking critters in it and they soon acclimatized to his antics.

Bear in mind your intentions... If its a great field but surrounded by homes, its not best suited for endless circuits - touch-and-goes - loitering. If you intent to launch and disappear for a couple of hours, that's quite a large difference. (I would commit to the idea that you will launch and at least move off to a remote spot to tune your low level skills) A remote field with sheep is best suited for the early days of safely loitering over your launch spot... The sheep keep the grass short... They soon acclimatize to you but will leave you be and you will be reasonably out of earshot of any potential complaints. Cows are a pain in the ass when they get used to you, they tend to get pretty cheeky and can cause problems

Not sure they have the power to weight ratio or efficiency of permanent magnets. No idea... Cant see it being much more than 3 liters per hour but I cant see it lasting very long running flat out for long periods. No There is an argument that a well tuned carb can give more hp so besides the auto mixture tuning for pressure change, its added complexity and weight start to look like it wont earn its keep on a paramotor.

I looked at the conundrum a while ago (mainly to solve a "dirive" specific issue so it was purely dc motor driven prop) It seems you are likely to lose some power, efficiency and gain some weight. A smaller motor running at constant max power/efficiency needs to supply cruise current (Maybe 5~8kw?) and enough surplus to charge a pack in reasonably short order (2~5kw maybe?) for takeoff power and the occasional boosted climb. Save "some" weight with a smaller IC motor, gain weight with a large alternator, the DC drive motor, battery/capacitor, etc... An accumulated 15kw might be ok ish for takeoff power... 20kw+ would be better and you'll need at least couple of minutes at that. (Small pack (10Ah?) with massive discharge) I built a 12v generator for my camper years ago using a 100A alternator on a honda GX100 (classic Honda generator engine) and that alternator must have weighed 5kg and would get VERY hot if I pushed it much passed 20A @14.8v (nowhere near the motors 1.5hp potential but its lasted thousands of hours so far... its getting tired now though) Alternators are simple but very inefficient and my unwillingness to have two large permanent magnet rotors and an inverter (and learn all sorts of new shit) put an end to my exploration... A single permanent magnet rotor that can generate during cruise and boost when you need it would make more sense (would probably need two winding schemes) but that would place me back into long drive shafts and exotic drive coupling so I left the idea there. I do like the basic principle but it may be an uphill battle to get it to make any practical sense. Currently I fly a four stroke (15kw ish) and can get 50mpg in still air... Hard to beat that

The one you showed looks like a simple manual open auto shut... Not sure an auto mechanism would earn its keep on a paramotor

I would expect it would mention the valve in the startup procedure had it had one