Pneumatic Plane

i previously built an engine that ran purely on compressed air inside it uses a diaphragm to create an airtight seal against a piston which greatly increases its efficiency and i ended that video claiming that it was perfect for a model aircraft if only it was that easy this video is brought to you by the ridge wallet more about them later before mounting the engine straight to a plane i wanted to gather some more thrust data at different pressures but i instantly knew it was underperforming and the thrust data was showing less than half of what it was previously producing my initial thought was that the diaphragm had broken so i disassembled the engine but everything looked fine and the diaphragm was still intact i tried replacing the gears lubricating the piston and checking the bearings but it was still underperforming and getting worse while spinning the engine by hand i noticed it had some resistance when spinning in one direction but if i change direction it would spin freely for a few turns before there was resistance again which was initially very confusing but i had a feeling it was related to the threaded bolt that attaches to the connecting rod to the crank gear depending on the direction the engine was spinning the connecting rod would move up or down this bolt eventually coming in contact with either the bolt head or the gear causing a lot of friction in hindsight this was a terrible design but it also worked fine in all of my older engines and wasn't an issue in earlier tests my theory is that over time the force from the piston causes the gear to tilt slightly which then causes the thread of the bolt to grip the brass insert which essentially threads it like a nut to get around this i've redesigned the engine to reduce the vertical distance between the connecting rod and the bearings to hopefully reduce the twisting of the gear as well as increase the distance between the bearings for better support i also removed the bolt that attached the connecting rod to the gear and instead used a thick wire bent to a 90 degree angle this then spins freely inside of a brass insert and on the thrust test stand it outperformed every other engine i have previously made with 37 higher peak thrust and 26 more efficient than the previous diaphragm engine so now we have all this extra thrust to play with it would be nice if the engine can be regulated for a more constant power output the simplest method of regulating the thrust is to restrict the airflow into the engine like squeezing this tube i can vary the engine's speed significantly but we need a method of varying the airflow restriction throughout the pressure change in the bottle one idea i have is to seal the end of a syringe at atmospheric pressure and place it inside the bottle as the pressure inside of the bottle is increased the volume inside of the syringe will contract to equalize with the pressure inside of the bottle so my idea is to have this syringe move a small brass plug back and forth inside of a tapered channel when the pressure inside of the bottle is high the plug moves towards the narrow end of the channel restricting the flow into the engine then as the pressure reduces the plug moves towards the wider end of the channel increasing the airflow this requires some adjustment of the thin wire length to get the restriction perfectly matched to the engine rpm but it actually works surprisingly well for such a simple design in comparison to the unregulated engine its max thrust is about 0.7 newtons but lasts for a lot longer which i hope will help when trying to power a model aircraft speaking of aircraft let's start building one i 3d printed some wing ribs using color fab's lightweight pla filament which foams up when printing making the parts far lighter than regular plastic these were then glued onto a single layer sheet of foam as i want to keep the weight as low as possible i also constructed the fuselage from thin foam board but there was a slight issue it's currently midnight and i've just checked the weather forecast tomorrow is the only day for the next four to five days with low wind and the plane is quite far from being finished so i didn't bother filming much more and took this photo with my phone at 1am it has radio controlled rudder and elevator and weighs just 296 grams with a 1.4 meter wingspan let's give it a glide test so it turns out that strength and weight might be inversely proportional i glued it back together and ran around a little with the engine running to see if it had any chance of sustaining flight but it wasn't looking very promising either way i still had to throw it i think this plane needs to shed some weight so i took out the radio control gear and strengthened the fuselage and because i had a few days to spare before the wind calmed down again i decided to completely redesign the engine again this version 5 engine works the same way as the previous engines but with a few modifications the first being the removal of the 90 degree bevel gears which allow the piston and connecting rod to directly drive the output shaft the cylinder head is very similar internally to the older versions but instead of a 3d printed bottle cap it mounts straight to a standard bottle cap with a few screws and a rubber washer the reason for this is the 3d printed caps have to be printed flat to achieve a precise thread but this is also the weakest direction to print as all the pressure in the bottle is held back by the layer strength of the material which isn't always enough so i often design the caps with excess material to withstand the pressure whereas standard bottle caps are injection molded making them stronger and lighter this results in a weight saving of 17 percent over the previous version 4 engine i also realized if i drastically increase the size of the exhaust ports i should be able to aim my high speed camera at the diaphragm and you can see the piston move up to open the inlet valve then the diaphragm expanding and breaking off from the piston exhausting the pressurized air once mounted on the plane the total weight of the aircraft is 243 grams which is about an 18 percent weight reduction so let's see if this glides a bit better so it's currently about 10 a.m and uh it's quite a frosty morning it's below zero degrees celsius so freezing point so i don't know how well the diaphragm is going to hold up whether the rubber is going to be stiff in his temperature but this is the lightest plane i think i've ever built and the most powerful engine i've ever built so if this doesn't fly i don't know what will right three two one sounds like it's really underperforming i wonder if that's a cold temperature with a diaphragm or it might be actually because looks like that valve has to let the air out freezes i can't see this working in this cold temperature it's just massively underperforming as soon as i come outside as i haven't quite figured out how to change the weather just yet my next best option is to pressurize the bottle inside where the air is warmer right this is the highest pressure i've done it too so far so hopefully the bottle will stand some pressure and then quickly run outside and launch it he's gonna hit the tree he's gonna hit the tree [Applause] turns out rubber diaphragms don't like cold temperature who would have thought the plane's rudder was purposely adjusted so the plane would fly in a left-hand circle which wasn't working very well in such a tight space i think that may have broken the engine yep that's pulled the engine through the bottle lid i replaced the bottle lid and straightened out the rudder to see if it collides with something a little softer huh oh my gosh so that's completely destroyed the engine the whole crankcase is just split in half i guess the remains are out in the field so there's the propeller and the crankcase and here is the piston seems like we're missing the wire conrod though [Applause] i think with a little more weight saving and some warmer weather this plane might actually be able to fly a full circuit or maybe my aircraft power source needs to change like my wallet i've been using this wallet for maybe the last eight to ten years and it's terrible do you know how awkward it is to open a velcro wallet in 2020 well i didn't until i tried this wallet from ridge i honestly love the design of these wallets as they've taken an everyday item that we all use and modernized it with a sleek industrial look including carbon fiber gunmetal burnt titanium and over 30 more and these materials add a layer of durability which means each wallet comes with a lifetime warranty the wallets hold up to 12 cards plus room for cash on the side so they will easily fit into your front pockets so to swap out your old bulky wallet for a new ridge wallet visit ridge.com forward slash toms10 to see their holiday guide and use promo code toms10 to get 10 off your order with free worldwide shipping and returns the link will be down in the description below thank you very much for watching this video this is in fact my third attempt at making an air powered plane and by far my closest to achieving a sustained flight in fact the first version was almost exactly two years ago and back then there were just 46 000 of you following this youtube channel and we've just passed over half a million very recently so i honestly can't thank all of you enough for subscribing to this youtube channel and supporting all my videos this is going to be the last video of 2020 but i have loads of plans for next year um so i hope you all have a great christmas and a happy new year if you enjoyed this video it'd be great if you could leave a thumbs up down below if you're new to my channel and want to see more videos similar to this then please click subscribe down below and a massive massive thank you to all of my supporters over on patreon.com for supporting my projects i honestly couldn't do without your support so thanks once again thanks again for watching and i'll see you in the new year goodbye

Channel: Tom Stanton

Views: 3,555,419

Rating: 4.9189329 out of 5

Keywords: pneumatic, compressed air, compressor, air power, air powered, aircraft, plane, radio control, DIY, air plane, engineering, engineer, RC plane, homemade, 3D printer, 3D printed, engine, air engine, air motor, wing, free flight

Id: I1Of1WRo38s

Length: 11min 45sec (705 seconds)

Published: Fri Dec 11 2020