That's a very clever solution. Te two Motors as twin configuration seems to be the key. So it's adaptable to most gliders likes flex wings and rigid wings as well. And I think it's possible to launch ontje trolley. Very cool. Good design.
Thanks. Yes twin is key. I built an ehelp as well which works really well on falcon. However for a glider mount solution their is no way to go with a single engine due to the larger prop size required. Also only works on high aspect ratio glider. Need to finish upgrade to bigger motors and I think I should get 200-400fpm climb. I'm also leaning towards open sourcing after a little more testing.
Hello! I admire the elegance of your solution. I apologize if the answer to my question was given in the video, but my English is weak. Please tell me what thrust the engines develop and what diameter propeller do you use.
The motors and props in this video put out about 20kg of static thrust (10kg each) with a Mad M6 motor and 19.68x10 wooden gemfan props. The upgraded Mad M10 motors with 22x10 wooden gemfan motors put out 32kg of static thrust. I've upgraded to CF folding props RASA CFK Propeller Folding 21/15,5" MAG ONE which are mounted at about 22" instead of 21. Haven't put those props in test stand but suspect its about 35kg.
Nice work Charles. I'm a model airplane guy and have been electric only since about 2000. I've been thinking about an electric ultralight for a while now and have been collecting data on setups. Have you ever used the low voltage alarms that plug into the balance connector on the batteries? I use them on my electric bike and back when I was running 5000 mah packs they would tell me when the packs were sagging below 3 volts with a quite loud repeating beep. I still puffed a few of those packs but they were given to me so the price was right. I've since went to 16000 mah Mulitstar packs and I had two that were giving me beeps way before I was done discharging the pack. I've since took the bad cells out of one of the packs and since then it's been working fine. The bike pulls at most about 32 amps so I'm not running them that hard, but it cut a couple of rides short last summer. It turned out that a 4S pack I thought was 16000 mah cells actually was a 4S 2P with two x 8000 mah cells in parallel. I took the two bad ones out and now it's a 3S pack I run in series with others but it runs fine. I've got to get to work on my design.
I've always been afraid that with a Mosquito harness you could set your harness on fire. I like the idea of have the batteries as far away from the body as possible. If you had to, you could throw your chute and cut away from the glider if the batteries did start on fire.
Really nice work. I was thinking something integrated in the keel in those times... but the problem is the pitch trim and the risk to brake it in case of excessive flare. Anyway... the batteries inside the sail are a potential deadly risk, because they are Lipo batteries and the risk of explosion/burning exists. Better to have the batteries in a place were you can bail them out in case of fire.
You make some good points. My thoughts below: 1. Pitch trim is my biggest concern. Most people I've talked to compare this to the Soarmaster which is somewhat relevant albeit 2x the weight and mounted on 25 year old gliders with different flight characteristics. There is a great accident report with lots of data on the Soarmaster here: assets.publishing.service.gov.uk/media/5422fdfa40f0b6134200087d/1-1983_Hang_Glider.pdf. There was also an article by Mark Stucky on the Soarmaster in Hang Gliding Magazine here: issuu.com/us_hang_gliding_paragliding/docs/2008_08_hgpg. Mark was kind enough to speak with me about his experience which cemented my thought the getting the thrust line right is paramount. For me the center of mass of my glider and harness is exactly 17in above my back plate. I have laser pointers mounted to the motors so I can dial in the thrust line on the ground. However I plan to make an in flight adjustable thrust line on the next version. 2. Yes you could break unit or keel on excess flare or bad landing. Since this doesn't pose a danger to pilot beyond normal flying my thought is who cares? Fixed glider / unit and learn to land better :) 3. While lipos are a risk and danger its one that can be managed. Flying is a risk but we do it anyway. Many have been flying the ehelp with no issue video here: th-cam.com/video/hk-2uNuh5YU/w-d-xo.html as well as the Open PPG info here: openppg.com/. Also the biggest risk of exploding and / or fire is during charge, not discharge. My thoughts on how to manage are below: - Use high end batteries and operate well below C rating - Don't use if puffy - Don't fly in cold. Low temps increases resistance of batteries which if followed by a big current draw can result in overheating. Only practical place you could mount batteries to eject is on harness which isn't ideal for reasons I stated in another comment. On my to do is to design a custom BMS system with temperature monitoring and a heated sleeve to keep batteries at right temp. However over time as battery tech improves I think this issue will go away.
@@cwallen32 point 2: the problem was related to my idea of design, not your project. In my design the problem was that even with a perfect flare where sometimes your keel touch slightly the ground while stopping, could have been damaging for the motor/propeller. Your design works, even if I don't like to see something external of the keel... but is just question of taste. Point 3: yes, batteries are going to be better in the times and is right what you say... but in any case I would have it where I can deploy and where they would not fuck my glider and rescue. What did you use on your 3d printer? PETG?
@@DavideFinziCarraro For 3d printer it depends on part. Orange stuff is ASA for strength and resistance to UV, Nylon for clips around keel on battery for flexibility, CF-PC for motor mount spacer parts for heat resistance. Didn't use any PETG, prefer higher performance plastics.
The back design is good but the battery on the keel is not a safe and smart idea.. I wouldn't use such device.. in case of fire, you are doomed.. the entire strap system that you hang on is nylon and that will melt with a little heat and you be lucky if it melts because those molten lithium particles will fall right on your back and burn you before you get a time for deployment of the parachute that will again not work and melt in contact.. the problem is those battery locations.. Also it has to be designed in the way that batteries get disconnected and fall below while holding into a case hanging from a thin steel wire so the fire hazard go down and stay a safe distance from the pilot.. I did this on my paramotor when I was designing it , I am using a lithium battery for engine start and still have made a small fire wall and steel wire connections and a spring, pins and heavy duty zip straps to hold it on place but in case of fire those straps will melt and the springs will shoot out the battery away from the paramotor.. you should think about how to separate the batteries from the entire pilot proximity.. Also the thrust you need to actually get bearly off the ground is Total take off weight/ true aspet ratio in flight ( considering the gear set up ) = minimum required thrust True aspet ratio is. Total glide ratio on new set up / 2 And you need to have minimum of twice that power to perform as good as the mosquito and if you want a better design, you need to make it that thrust about 2.5 times the minimum thrust on the calculation above.. Assuming your total take off weight with your system around 300lbs / 7 true aspect ratio = 43 lbs , And you said they make 20 kg which means 44lbs so it bearly takes off from ground at sea level at 68 degrees Fahrenheit or 20 degrees Celsius.. you need 2.5 times than means 20kg x 2.5 = 50kg ( 110 lbs) 20 kg is not sufficient enough And if you try to use more powerful motors, they will drain the batteries I just 2 minutes and all that work and investments for 2 minutes doesn't make any sense.. th-cam.com/users/shortsQK_df-MN_mI?feature=share
Your point about the safety of LiPo batteries are valid and my biggest concern. However, your assessment of what would happen if they were to catch on fire is pure speculation. The batteries are on the keel tube but very close to the nose of glider and not that close to the hang strap. While a fire could spread to the hang strap and melt it off that's not my biggest concern and may be a positive. I fly with 2 chutes which are both connected to the harness and don't go up the main line so in your scenario I would be disconnected from the flaming glider. My concern is the following: the batteries melt through the battery holder and slide down the wing (melting through the cloth sheer ribs) and putting the glider into a flaming spin, or the whole sale catches on fire among other things. Given I'm flying at 25-30mph I'm not terribly worried about the "molten" batteries falling on me" I think they would bounce off and keep going i.e. gravity and wind would see to that. There are a whole lot of other things that could go wrong as well with a fire but don't want to speculate. With that mentioned I'm actually much more comfortable having the batteries in the wing then strapped to my back as they are on all the ehelp designs. In the end I agree that LiPo's aren't safe and there is a lot of risk with the system. However, using high quality batteries, operating them well below their limits, and maintaining them well can help offset this risk. In the longer run I expect battery technology to advance and replacing these with safer solid state batteries. With respect to your math on thrust and flight time, the goal of this project is to have enough power to climb to 1,000-1,500 feet. If that's 2min at 500fpm or 10min at 100fpm it works. Based on my math and actual tests this is achievable.
Nice job... I'm waiting for battery power density to go up a bit more and then I'm going to convert my Alatus AL12M from gas to electric. It only holds about an hour of gas so I'm only one battery advance away to match the flight time I currently have.
Don't think that would work. While Lithium-ion, has better energy density and is somewhat safer, can't get same discharge rate i.e. c rating is too low. Would work for a larger pack however for the small packs i'm using i dont think it would work. I could go with a larger pack but don't want the extra weight.
Very cool. Well done, Sir. I have a question: would this work well with a supine/suprone race harness, or would it be best to mount your motors on the harness itself for that kind of pilot orientation?
Should work regardless of type harness. However it was designed for only very high performance gliders i.e. WW T2, Laminar Z9, Combat, etc. The aspect ratio of lower performance gliders is too big so there isn't enough keel / open space to mount on. Also I'm concerned that lower performance gliders will have more flex and the keel will float more which may have negative effective on control.
Not intended for flat land foot launch. Thrust line is ground changeable and typically slightly above center of mass depending on setting at least when harness is clear of prop. I anticipate this will create a nose down effect near stall while under power which. Goal is to launch without power from low mountain, hill, scooter, etc and have 7-10min of power to climb up to 1000 ft and find thermal.
Also you should check out Reidar's Channel ( th-cam.com/users/AcrodesignerLNSNI) he has lots of info on the ehelp which is ground launcher. I made a carbon ehelp in 6 weeks. However I wouldn't try to ground launch my laminar with an ehelp, the run is too long.
Thanks, Charlie! I've been looking at powered ways to get airborne, many (of the very few available) good days up here I look up at the sky with no way to be up there. I'll check out the e-help, which I would need to use with more of a floater glider I guess. I doubt there is any powered harness I could use on the Combat C though due to the tail.
Charles, Is this your own design? I'm thinking that it is, but it looks to be professionally manufactured. I'm also wondering why you have the "under frame/trike"? You don't really need it if the props are 2-3 feet off the ground when the glider is sitting on the keel. Maybe you just like to roll off the ground on take off. Have you taken off by running with motors on? I developed a similar concept about 2-3 years ago, but have not yet made a prototype. I have a few more questions but hope you will answer what I asked here before I go on. Scott W
Scott - I designed with Fusion 360 and manufactured in my workshop with CNC mill, cnc router and 3d printer. The "under frame/trike" is a standard aerotow cart. You can see me launching with it here: th-cam.com/video/oqqEOvN7l8I/w-d-xo.html. I've also foot launched with it from a mountain launch th-cam.com/video/vLN5Kvkvwa0/w-d-xo.html. I've flown with it 4 times to date and am still dialing things in. I don't plan to ever flat land foot launch it. Its designed for a high performance hang glider which stalls at a high speed so would require a very long and hard run. Also it won't fit on a beginner gliders due to long chord and I'd be worried about the keel floating around. The keel is relatively well locked into position on a high performance glider and adding VG will further limit float. I've flat land launched my falcon with the carbon ehelp numerous times video here: th-cam.com/video/2QEa9IL_ZlM/w-d-xo.html. The next logical step is to move from aero towing to scooter towing. After which, assuming I continue to get positive results, I plan to design and build an electric powered cart similar to a standard aerotow cart to allow for flat land self launch.
@@cwallen32 Thanks for the quick reply! It's great that you have all you need to make such a nice looking power unit. The version that I have dreamed up (but not yet built) is intended to be foot launched from flat ground. I have seen other single prop versions being foot launched from flat ground so I know it's possible. One thing I would say about about launching from the flat is that a high performance wing will produce better lift at min sink speed. So, I would figure that it wouldn't take many strides (into nice a prevailing wind - around 10-12 mph) before you start "moon walking" and then you're off the ground. The glider I would use for my version would be a WW Talon 140 (first version). I also have a WW Sport 150 available and it may be the better option due it's larger wing area. What I like about having duel props, more or less in line with the keel, is that when taking off they are high above ground obstacles like medium to tall grass. Also, with counter rotating props you zero out the rotational torque. It could also be useful to vary the speed of the motors to help with yaw/turning. BTW - I was responding to your 10/3 video when you responded here. So I'll go back there and finish up with that comment. : - ) Scott W PS - For some context I started flying in 1975 and when a member of the USHGA (Then USHPA) I held a Master rating. With an e-assist HG I can fly at sites where the local USHPA chapter has threatened to literally beat me up if I were to try and fly. But with lots of hay fields in the valley I could fly with no interference.
I wouldn't foot launch a 140 Talon with a twin setup from the ground, just my 2 cents. Its an unproven design with a lot of variables that need to be dialed in to make safe. Yes you can foot launch an ehelp (single prop) proven design from the ground with basically any glider but will require a more substantial run with a higher performance glider. Obviously a 10-12mph wind changes things but that's a very strong wind on the ground, likely blowing 25 mph in the air. You should check out Reidar and my ehelp videos.
3 reasons it won't work on a Falcon: 1. Mounting: The chord is too long so there is no where to mount on keel that keeps props clear of ground and wires. I tried to fit on my Falcon 3, it doesn't work. 2. Power: The twin setup is 5,500 watts max (hence the name), however I plan to increase to more but it would still be under powered given the low performance of a Falcon. 3. Rigidity: A Falcon is very flexible and the keel can float significantly and thus change thrust direction which may have negative affects on handling. Note this is just a theory, not tested. If you're flying a Falcon you've already sacrificed performance so you should go with a simpler design such as my carbon ehelp. th-cam.com/video/2QEa9IL_ZlM/w-d-xo.html. I've open sourced the design files and BOM a link is in the notes to the video. I flew the ehelp a few days ago; ground launched and managed to climb under power to 600ft AGL backed off motor and climbed in light lift to 900ft AGL then it turned on and I got to 6.5k ft AGL power off and flew for around 1 hr. ayvri.com/scene/z15yrzn1jx/ckovqfcj10001266lqm12g0rf I've had 4 flights with the XTM5500 and it works really well. I need to make some improvements but haven't had time. Link here to 4th flight test: th-cam.com/video/oqqEOvN7l8I/w-d-xo.html Its very unlikely it will ever be commercially available. Its a side project which I find fun. Once I get a little more test data I'll likely open source the design, however, it isn't easy to make. I designed it in Fusion 360 and all the parts are either 3d printed with engineering grade materials, CNC milled from 7075 T6 aluminum, or CNC cut from carbon fiber plate. I even CNC cut standard wood props so they fit in the custom folding hub. If you're flying a Falcon, you should make a carbon ehelp. Its really easy to make compared to the XTM5500 all the design files are open sourced, cost is about $2,500 all in if you make yourself and given the limited number of parts you could probably have made for $1000.
This is potentially a lot simpler to build than a powered harness, but unless it is cheaper, I much prefer a powered harness instead of a powered wing... Why did you choose this way?
Actually much more complicated to build then a powered harness. I designed and built an ehelp in 6 weeks from CAD to working rig video here: th-cam.com/video/4Z1WWt682bY/w-d-xo.html. It was under powered and I've since added a bigger motor prop combo. Some reasons for glider mount below: - Thrust line swings around on powered harness. When you move your body unless perfectly coordinated and lined up the thrust line can have major control issues and isn't efficient. I have an LD Explorer (similar to Mosqiuto) if you turn left for example and your feet swing out to the right then the thrust line is driving you into the turn, it kinda feels like you're getting pushed into a spin, backing off motor solves this. - Can't aerotow with a powered harness as it doesn't fit in standard cart. - Have p-factor with single large props etc. Twin is counter rotating. - Need special or modified harness. Most importantly though the goal of this project was to build a very minimal unit to enable sustained flight for 5-10min to find the 1st thermal and climb out. My main site (cool video here: th-cam.com/video/ycU4ZDrqKA4/w-d-xo.html is just 500ft agl) requires 15-20mph wind for the ridge to work otherwise you need to launch in a really big thermal right at launch which never seems to happen. On a weak wind day with the XTM 5500 I could launch with min of 5mph, and fly to nearest cloud. Further it could allow for scooter towing to be a means to achieve soaring flights.
Doesn't work on a Falcon. I have a 140 Falcon I purchased to test it on and the chord is too long. You need a high aspect ratio wing to ensure there's enough keel to mount and stay clear of the ground. I built a carbon ehelp that works very well with a Falcon. Here is a link to an old flight th-cam.com/video/4Z1WWt682bY/w-d-xo.html. Since then I've upgraded the motor/prop combo and it can climb to about 1,000-1,500 ft on a charge. I'm in the process of organizing all my CAD files, BOM, code, etc and plan to open source the carbon ehelp design. Also if you inverted my design the thrust line would be well above the center of mass of the glider and likely create major issues.
@@cwallen32 OK,, I figured with the drag of a single surface you could adjust the angle enough, but that would take a lot of trial and, the big word, ERROR to figure out. Best done after launch up high I suppose. AND a willing and able pilot of coarse. Love your ideas and will check out the link you supplied. I live in Arizona and am only a 10 hour H2 pilot, but with all this flat land around me and very few mountain launches that I don't even qualify for yet, this, even after H3 would be a great option to not have to travel for. Especially in the winter when it's cooler to fly but have the inversion layer as a ceiling. UGHhh!!!! LOL Bless you and yours. Hope you much success.
Will it possibly be commercially available? Any idea what the price range might be for something that can be used to take off from flat ground and gain at least some 500m?
Don't plan to make a business out of this project, it just can't compete with my day job. However, may make and sell a few if I get good results, though not sure what I would charge, as its very labor intensive. You can make an ehelp for about $2-3k which will get you to 500m. Its also a proven design. If you're interested can point you in right direction on this.
The earlier prototype has been test flown, haven't flow with this one yet. Was planning to test it in Florida at the comps. However COVID killed those plans. Putting batteries in harness isn't ideal for the following reasons: 1. would make wire run too long, would likely need to go to 4awg wire adding additional weight 2. As you increase distance from batteries to ESC it needs to be compensated with capacitors to protect them from voltage spikes caused by inductance in wires. Could add more caps but these are currently the scariest part of the setup. 3. Battery and propulsion unit are perfectly balanced around the hang point. If the batteries are on the harness you would need to add a counter weight in the sail to offset the motor weight by adding an additional 9.2lbs in the sail. 4. Would need to find way to mount batteries to harness which would likely be outside and require modifications to the harness. Goal was to have unit clip onto any glider with very minor modifications. I drilled 2 holes in my laminar and cut the keel fairing off, however I'll sew a zipper on the keel fairing so I can take it on and off in future.
Flew with it 2 weeks ago. It was a very thermic day which was good as i was able to get up to 3k over launch test but not good to get a feel for effect on glider from power unit vs air. Overall the extra 15.5lbs was very noticeable when ground handling but the glider was fine once in air with power off. Glider was a little skaty under full power but very manageable. One issue I had was props didn't fold back when motors were turned off and flying with 2 windmilling props was like flying with a drogue chute. There's no brake on ESC so I was banking on big springs to pull blades back in which didn't work. Working on a few solutions to this now, but its an easy fix, . I'll post a more detailed update in the coming weeks but bottom line is the setup works but needs to be dialed in.
Hi Charles…. we’ve met and flown together at the ECC meets. I to am working on a twin motor design only it’s mounted totally different from yours. How can I get in touch with you? Nick Caci.
I'll likely post an update video to my channel and will send to Davis at the OZ report and he'll likely post. Since making the video I've flown with the unit with positive results. Unfortunately the props won't fold after shutting the motors so I need to move to an ESC with a brake which is a major redesign, however I'm finishing up a mechanical brake as a band aid solution. Plan to fly it this weekend and will post a comprehensive update in the coming weeks. Also plan to post more details on my Carbon Ehelp and will open source all design files.
@@cwallen32 awesome , thanks, looking forward to all that. Good luck! I don't quite understand, why don't the props fold when you cut power? Also just for you to consider, I was talking to Miloslav from ultralightdesign.cz/ a while ago, and he mentioned that he's actually electronically slowing down the ramp-up of power when starting the engine to prevent the prop unfolding too fast, hitting the limiter, and over time breaking due to this repeated stress. And I saw how the prop unfolds in person, it was nice and smooth.
You are connected to glider so the thrust line in relation to the center of mass (glider / pilot combo) is what matters. There's some risk that in turbulence if you go weightless the center of mass would become just the glider and this could result in unwanted pitch changes do to power.
Correct 2x6s, there a bunch of other errors in video as well but its not a product promotion more a project overview so didn't feel like reshooting. MAD 180kv drone motors, tried about 6 different motors before settling on these. Props are 19.7x10, however I think I may be able to go as high as 21x12 assuming they are only run in the air.
@@cwallen32 Nice job, those motors are good and your battery choice is good. The higher voltage will run cooler. Keep bumping the prop diameter on the ground until you hit the ESC amp limit knowing it will unload 10% or so in the air.
@@atlantahobbyuavexperts4759 Ha, exactly what I did. Video of my older test stand here: th-cam.com/video/7zbRbz_ZH30/w-d-xo.html. Mfg has motor able to pull 68amps I had it at 61.6amps in test stand (left a little room to be conservative). However, it was in very small room when I tested in big building that allowed air to move around amps dropped to 50amps. So I think in air at 25mph should be able to up prop size. Working on data logging now so I can see amps pulled after flight and adjust accordingly.
So would I but not going to happen with this design and a high performance glider. Very hard to get battery back on keel and strapped in. In 5-15 years when batteries go solid state the risk will go away. However with an ehelp its possible to design an auto-eject system which I'm already working on.
@@adventureswitharizonaart6117 Cool. However this is definitely not for a H1. I've been flying since 1996 and am very careful with my testing and the conditions I'm willing to use in.
Not selling nor do I have any plans to ever make a business out of it. Plan is to open source the design, created FB page here: facebook.com/groups/904566026835865.
100% disagree. If the hang strap goes slack then the pilot is taken out of the mass equation. i.e. the center of mass would just be that of the glider which would be near the under surface of the glider. The thrust line is currently about 14 inches above the pilot so a few feet below the under surface of the glider. Going slack would cause the glider to pitch up not down. Also you're missing the whole point of this. If the air is that rough there is no need to fly under power. The end goal is to create a lightweight platform that doesn't have a meaningful effect on flight control in a power off situation but allows the pilot to either scooter tow to a few hundred feet or launch from a training hill and climb to thermal level i.e. 1000ft. It would also be useful as a back up if your about to sink out and want to push to the next thermal before landing. The longer run goal is to design and build an electric powered launch cart so you could safely launch from flat ground, climb up to a thermal and shut the engine and go soar.
Yes, 3 flights. I've made refinements after each flight. Plan to have another flight weekend of Sept 26 weather permitting. Bottom line is it works well but is under powered, just sustains zero sink doesn't climb. However its really easy to add more power. I was a 2-3miles away from the tow field on last test flight around 800ft and was able to make it back arriving at about 400ft. I have video and track logs just haven't had time to compile and do a write up.
You really need to put the power unit on your harness.... in the early days 70’s .... there were some fatalities when it was discovered that a high thrust line created pitch instability.... I strongly suggest you change this aspect of your design.
Ha that's the most common response and 100% disagree, core of my design is to get thrust line right, which isn't done right on a powered harness. Also thrust line is only ~6 inches above my center of mass, soarmaster was very high about 6 inches below sail. Please read some of the other comments as this has been addressed. If you have an interest you should read the in depth accident report on the soarmaster link in another comment. Done my research and spoken with pilots who flew the soarmaster. In my opinion the soarmaster was poorly designed over 40 years ago, don't see that as a reason to abandon concept, especially if thrust line can be properly engineered.
Charles Allen I flew a soar master and lost friends to it while trying to develop it..... we then went onto develop trikes that did not exhibit the same problems.... yes there are issues with the thrust attached to a harness, namely rotation, which is manageable..... for your sake I hope you are right....
@@seanwestrope3783 Thanks for the feedback. Given the low power, low weight, and dialed in thrust line I'm optimistic it can be developed safely. Also the goal is not to developed a motor glider but rather a minimal unit to sustain flight to find lift.
@@cwallen32 problem as we discovered was, as by way of illustration, that you wouldn't think of putting a thrust line on the control surface of a conventional wing (flaps, ailerons..etc) nor on the control linkages......these elements effectively work around the thrust line, otherwise the aircraft would be obviously unstable. On a flex wing the whole wing surface and the whole frame is in effect a control surface and the control linkage. For a flex wing the only part of the whole a aircraft that is not part of the control is in fact the pilot (albeit he/she does the controlling). It was this realisation that moved us towards a trike configuration. What you are developing is a self launch HG, which I think is the way forward because it would be more convenient for pilots. You are also now beginning to get the materials and technology to make this practically possible without disproportionately affecting the HG performance. It is exciting what you are trying to achieve but it is also important to understand how and why we got to some of the solutions we adopt today. I wish you every success.
@@seanwestrope3783 Thanks for the thoughtful feedback, much appreciated. To clarify though this is not meant to be a self launch power unit. The required power to get off the ground would be too high to be safe at this stage of development and the flight speed would be too close to stall were there are known issues form the soarmaster. It was originally designed to provide enough power to maintain sustained flight (i.e. zero sink) though I think it should produce 100-200 fpm climb after taking off via another means. You make a great point regarding power being attached to a control surface. Hence why I'm keeping the power low and don't believe this will work on a low performance glider. One difference between gliders 40 years ago and a modern high performance flex wing is the amount of flex and rigidity. Comparing my falcon to my laminar in terms of flex the falcon is more flexible, likely closer to a 40 year old glider and the keel can really swing around. The keel on my laminar Z9 doesn't swing much and if I go full VG things barely move. I'm optimistic that if I get the thrust line dialed in there will be a safe envelope of speed, bank angle and pitch that can be flown. Modern electronics are also something didn't exist in the past. Both the remote and power unit have dual core 240mhz processors which I can hook multiple sensors up to. I have a 9 DoF IMU I plan to connect in future which could kill motors if pitch and/or bank angle goes above or below set angles.
That's a very clever solution. Te two Motors as twin configuration seems to be the key. So it's adaptable to most gliders likes flex wings and rigid wings as well. And I think it's possible to launch ontje trolley. Very cool. Good design.
Thanks. Yes twin is key. I built an ehelp as well which works really well on falcon. However for a glider mount solution their is no way to go with a single engine due to the larger prop size required. Also only works on high aspect ratio glider. Need to finish upgrade to bigger motors and I think I should get 200-400fpm climb. I'm also leaning towards open sourcing after a little more testing.
The shape of things to come 👏👍
Hello! I admire the elegance of your solution. I apologize if the answer to my question was given in the video, but my English is weak. Please tell me what thrust the engines develop and what diameter propeller do you use.
The motors and props in this video put out about 20kg of static thrust (10kg each) with a Mad M6 motor and 19.68x10 wooden gemfan props. The upgraded Mad M10 motors with 22x10 wooden gemfan motors put out 32kg of static thrust. I've upgraded to CF folding props RASA CFK Propeller Folding 21/15,5" MAG ONE which are mounted at about 22" instead of 21. Haven't put those props in test stand but suspect its about 35kg.
Impressive! Have you considered, or is it possible to store the battery pack in the harness?
See my other comment.
Well done! Only concern is the batteries in the sail. If they fail...
Read up on EarthX batteries
Thanks will take a look.
th-cam.com/video/bKDtvQYTuqY/w-d-xo.html
th-cam.com/video/m9-cNNYb1Ik/w-d-xo.html
mike m it might be better than on your harness.. because you still have a reserve on it. If your harness catches fire you are most likely dead.
Rai3a
Nice work Charles. I'm a model airplane guy and have been electric only since about 2000. I've been thinking about an electric ultralight for a while now and have been collecting data on setups.
Have you ever used the low voltage alarms that plug into the balance connector on the batteries? I use them on my electric bike and back when I was running 5000 mah packs they would tell me when the packs were sagging below 3 volts with a quite loud repeating beep. I still puffed a few of those packs but they were given to me so the price was right. I've since went to 16000 mah Mulitstar packs and I had two that were giving me beeps way before I was done discharging the pack. I've since took the bad cells out of one of the packs and since then it's been working fine. The bike pulls at most about 32 amps so I'm not running them that hard, but it cut a couple of rides short last summer. It turned out that a 4S pack I thought was 16000 mah cells actually was a 4S 2P with two x 8000 mah cells in parallel. I took the two bad ones out and now it's a 3S pack I run in series with others but it runs fine.
I've got to get to work on my design.
The voltage is monitored and motors are shut off when it drops below 40.8 (3.4v per cell).
great concept! is it possible to launch off even ground with just a dolly and no towing?
I'm sure this was discussed in the comments below. However, anticipate needing a scooter tow or an empowered cart to get up to airspeed quickly.
I've always been afraid that with a Mosquito harness you could set your harness on fire. I like the idea of have the batteries as far away from the body as possible. If you had to, you could throw your chute and cut away from the glider if the batteries did start on fire.
Correct assuming your chute connects to the harness and not the hang strap. Also would need a hook knife.
Really nice work. I was thinking something integrated in the keel in those times... but the problem is the pitch trim and the risk to brake it in case of excessive flare.
Anyway... the batteries inside the sail are a potential deadly risk, because they are Lipo batteries and the risk of explosion/burning exists.
Better to have the batteries in a place were you can bail them out in case of fire.
Read up on EarthX batteries
You make some good points. My thoughts below:
1. Pitch trim is my biggest concern. Most people I've talked to compare this to the Soarmaster which is somewhat relevant albeit 2x the weight and mounted on 25 year old gliders with different flight characteristics. There is a great accident report with lots of data on the Soarmaster here: assets.publishing.service.gov.uk/media/5422fdfa40f0b6134200087d/1-1983_Hang_Glider.pdf. There was also an article by Mark Stucky on the Soarmaster in Hang Gliding Magazine here: issuu.com/us_hang_gliding_paragliding/docs/2008_08_hgpg. Mark was kind enough to speak with me about his experience which cemented my thought the getting the thrust line right is paramount. For me the center of mass of my glider and harness is exactly 17in above my back plate. I have laser pointers mounted to the motors so I can dial in the thrust line on the ground. However I plan to make an in flight adjustable thrust line on the next version.
2. Yes you could break unit or keel on excess flare or bad landing. Since this doesn't pose a danger to pilot beyond normal flying my thought is who cares? Fixed glider / unit and learn to land better :)
3. While lipos are a risk and danger its one that can be managed. Flying is a risk but we do it anyway. Many have been flying the ehelp with no issue video here: th-cam.com/video/hk-2uNuh5YU/w-d-xo.html as well as the Open PPG info here: openppg.com/. Also the biggest risk of exploding and / or fire is during charge, not discharge. My thoughts on how to manage are below:
- Use high end batteries and operate well below C rating
- Don't use if puffy
- Don't fly in cold. Low temps increases resistance of batteries which if followed by a big current draw can result in overheating.
Only practical place you could mount batteries to eject is on harness which isn't ideal for reasons I stated in another comment. On my to do is to design a custom BMS system with temperature monitoring and a heated sleeve to keep batteries at right temp. However over time as battery tech improves I think this issue will go away.
@@cwallen32 point 2: the problem was related to my idea of design, not your project. In my design the problem was that even with a perfect flare where sometimes your keel touch slightly the ground while stopping, could have been damaging for the motor/propeller.
Your design works, even if I don't like to see something external of the keel... but is just question of taste.
Point 3: yes, batteries are going to be better in the times and is right what you say... but in any case I would have it where I can deploy and where they would not fuck my glider and rescue.
What did you use on your 3d printer? PETG?
@@DavideFinziCarraro For 3d printer it depends on part. Orange stuff is ASA for strength and resistance to UV, Nylon for clips around keel on battery for flexibility, CF-PC for motor mount spacer parts for heat resistance. Didn't use any PETG, prefer higher performance plastics.
The back design is good but the battery on the keel is not a safe and smart idea.. I wouldn't use such device.. in case of fire, you are doomed.. the entire strap system that you hang on is nylon and that will melt with a little heat and you be lucky if it melts because those molten lithium particles will fall right on your back and burn you before you get a time for deployment of the parachute that will again not work and melt in contact.. the problem is those battery locations..
Also it has to be designed in the way that batteries get disconnected and fall below while holding into a case hanging from a thin steel wire so the fire hazard go down and stay a safe distance from the pilot.. I did this on my paramotor when I was designing it , I am using a lithium battery for engine start and still have made a small fire wall and steel wire connections and a spring, pins and heavy duty zip straps to hold it on place but in case of fire those straps will melt and the springs will shoot out the battery away from the paramotor.. you should think about how to separate the batteries from the entire pilot proximity..
Also the thrust you need to actually get bearly off the ground is
Total take off weight/ true aspet ratio in flight ( considering the gear set up ) = minimum required thrust
True aspet ratio is. Total glide ratio on new set up / 2
And you need to have minimum of twice that power to perform as good as the mosquito and if you want a better design, you need to make it that thrust about 2.5 times the minimum thrust on the calculation above..
Assuming your total take off weight with your system around 300lbs / 7 true aspect ratio = 43 lbs ,
And you said they make 20 kg which means 44lbs so it bearly takes off from ground at sea level at 68 degrees Fahrenheit or 20 degrees Celsius.. you need 2.5 times than means 20kg x 2.5 = 50kg ( 110 lbs)
20 kg is not sufficient enough
And if you try to use more powerful motors, they will drain the batteries I just 2 minutes and all that work and investments for 2 minutes doesn't make any sense..
th-cam.com/users/shortsQK_df-MN_mI?feature=share
Your point about the safety of LiPo batteries are valid and my biggest concern. However, your assessment of what would happen if they were to catch on fire is pure speculation. The batteries are on the keel tube but very close to the nose of glider and not that close to the hang strap. While a fire could spread to the hang strap and melt it off that's not my biggest concern and may be a positive. I fly with 2 chutes which are both connected to the harness and don't go up the main line so in your scenario I would be disconnected from the flaming glider. My concern is the following: the batteries melt through the battery holder and slide down the wing (melting through the cloth sheer ribs) and putting the glider into a flaming spin, or the whole sale catches on fire among other things. Given I'm flying at 25-30mph I'm not terribly worried about the "molten" batteries falling on me" I think they would bounce off and keep going i.e. gravity and wind would see to that. There are a whole lot of other things that could go wrong as well with a fire but don't want to speculate. With that mentioned I'm actually much more comfortable having the batteries in the wing then strapped to my back as they are on all the ehelp designs.
In the end I agree that LiPo's aren't safe and there is a lot of risk with the system. However, using high quality batteries, operating them well below their limits, and maintaining them well can help offset this risk. In the longer run I expect battery technology to advance and replacing these with safer solid state batteries.
With respect to your math on thrust and flight time, the goal of this project is to have enough power to climb to 1,000-1,500 feet. If that's 2min at 500fpm or 10min at 100fpm it works. Based on my math and actual tests this is achievable.
Nice job... I'm waiting for battery power density to go up a bit more and then I'm going to convert my Alatus AL12M from gas to electric. It only holds about an hour of gas so I'm only one battery advance away to match the flight time I currently have.
Will be nice, though may be slow, 5years? For an extra 3 pounds I can have 25 Ahm batteries or 78% increase, however cost goes up a lot.
@@cwallen32 Yes, I expect it to be an expensive leap. I hope Tesla battery day divulges something good. Then I'd wait for a wrecked car after that.
Wonderful setup - thank you for sharing!
Would it be a solution to use self-made Litium-Ion battery-packs instead?
Don't think that would work. While Lithium-ion, has better energy density and is somewhat safer, can't get same discharge rate i.e. c rating is too low. Would work for a larger pack however for the small packs i'm using i dont think it would work. I could go with a larger pack but don't want the extra weight.
Very cool. Well done, Sir.
I have a question: would this work well with a supine/suprone race harness, or would it be best to mount your motors on the harness itself for that kind of pilot orientation?
Should work regardless of type harness. However it was designed for only very high performance gliders i.e. WW T2, Laminar Z9, Combat, etc. The aspect ratio of lower performance gliders is too big so there isn't enough keel / open space to mount on. Also I'm concerned that lower performance gliders will have more flex and the keel will float more which may have negative effective on control.
Take my money already!!!!
Ha, doubt I will ever make this a business but if I get good results I may mfg and sell a few.
Charles Allen maybe you can sell the project for 3d printing the parts, or in a kit, so we can source the other parts on our own...
I will be your first customer!
Pretty cool, man! So this is intended just to get you to the next thermal, or is it strong enough to power you up on a foot launch, no hill?
Not intended for flat land foot launch. Thrust line is ground changeable and typically slightly above center of mass depending on setting at least when harness is clear of prop. I anticipate this will create a nose down effect near stall while under power which. Goal is to launch without power from low mountain, hill, scooter, etc and have 7-10min of power to climb up to 1000 ft and find thermal.
Also you should check out Reidar's Channel ( th-cam.com/users/AcrodesignerLNSNI) he has lots of info on the ehelp which is ground launcher. I made a carbon ehelp in 6 weeks. However I wouldn't try to ground launch my laminar with an ehelp, the run is too long.
Thanks, Charlie! I've been looking at powered ways to get airborne, many (of the very few available) good days up here I look up at the sky with no way to be up there. I'll check out the e-help, which I would need to use with more of a floater glider I guess. I doubt there is any powered harness I could use on the Combat C though due to the tail.
Charles, Is this your own design? I'm thinking that it is, but it looks to be professionally manufactured. I'm also wondering why you have the "under frame/trike"? You don't really need it if the props are 2-3 feet off the ground when the glider is sitting on the keel. Maybe you just like to roll off the ground on take off. Have you taken off by running with motors on? I developed a similar concept about 2-3 years ago, but have not yet made a prototype. I have a few more questions but hope you will answer what I asked here before I go on. Scott W
Scott - I designed with Fusion 360 and manufactured in my workshop with CNC mill, cnc router and 3d printer. The "under frame/trike" is a standard aerotow cart. You can see me launching with it here: th-cam.com/video/oqqEOvN7l8I/w-d-xo.html. I've also foot launched with it from a mountain launch th-cam.com/video/vLN5Kvkvwa0/w-d-xo.html. I've flown with it 4 times to date and am still dialing things in. I don't plan to ever flat land foot launch it. Its designed for a high performance hang glider which stalls at a high speed so would require a very long and hard run. Also it won't fit on a beginner gliders due to long chord and I'd be worried about the keel floating around. The keel is relatively well locked into position on a high performance glider and adding VG will further limit float. I've flat land launched my falcon with the carbon ehelp numerous times video here: th-cam.com/video/2QEa9IL_ZlM/w-d-xo.html. The next logical step is to move from aero towing to scooter towing. After which, assuming I continue to get positive results, I plan to design and build an electric powered cart similar to a standard aerotow cart to allow for flat land self launch.
@@cwallen32 Thanks for the quick reply! It's great that you have all you need to make such a nice looking power unit. The version that I have dreamed up (but not yet built) is intended to be foot launched from flat ground. I have seen other single prop versions being foot launched from flat ground so I know it's possible. One thing I would say about about launching from the flat is that a high performance wing will produce better lift at min sink speed. So, I would figure that it wouldn't take many strides (into nice a prevailing wind - around 10-12 mph) before you start "moon walking" and then you're off the ground.
The glider I would use for my version would be a WW Talon 140 (first version). I also have a WW Sport 150 available and it may be the better option due it's larger wing area.
What I like about having duel props, more or less in line with the keel, is that when taking off they are high above ground obstacles like medium to tall grass. Also, with counter rotating props you zero out the rotational torque. It could also be useful to vary the speed of the motors to help with yaw/turning.
BTW - I was responding to your 10/3 video when you responded here. So I'll go back there and finish up with that comment. : - ) Scott W
PS - For some context I started flying in 1975 and when a member of the USHGA (Then USHPA) I held a Master rating. With an e-assist HG I can fly at sites where the local USHPA chapter has threatened to literally beat me up if I were to try and fly. But with lots of hay fields in the valley I could fly with no interference.
I wouldn't foot launch a 140 Talon with a twin setup from the ground, just my 2 cents. Its an unproven design with a lot of variables that need to be dialed in to make safe. Yes you can foot launch an ehelp (single prop) proven design from the ground with basically any glider but will require a more substantial run with a higher performance glider. Obviously a 10-12mph wind changes things but that's a very strong wind on the ground, likely blowing 25 mph in the air. You should check out Reidar and my ehelp videos.
Wow nice
Only for "high performance" gliders? Why not a Falcon 4 or similar? When will you test fly, and will it be commercially available thereafter?
3 reasons it won't work on a Falcon:
1. Mounting: The chord is too long so there is no where to mount on keel that keeps props clear of ground and wires. I tried to fit on my Falcon 3, it doesn't work.
2. Power: The twin setup is 5,500 watts max (hence the name), however I plan to increase to more but it would still be under powered given the low performance of a Falcon.
3. Rigidity: A Falcon is very flexible and the keel can float significantly and thus change thrust direction which may have negative affects on handling. Note this is just a theory, not tested.
If you're flying a Falcon you've already sacrificed performance so you should go with a simpler design such as my carbon ehelp. th-cam.com/video/2QEa9IL_ZlM/w-d-xo.html. I've open sourced the design files and BOM a link is in the notes to the video. I flew the ehelp a few days ago; ground launched and managed to climb under power to 600ft AGL backed off motor and climbed in light lift to 900ft AGL then it turned on and I got to 6.5k ft AGL power off and flew for around 1 hr. ayvri.com/scene/z15yrzn1jx/ckovqfcj10001266lqm12g0rf
I've had 4 flights with the XTM5500 and it works really well. I need to make some improvements but haven't had time. Link here to 4th flight test: th-cam.com/video/oqqEOvN7l8I/w-d-xo.html
Its very unlikely it will ever be commercially available. Its a side project which I find fun. Once I get a little more test data I'll likely open source the design, however, it isn't easy to make. I designed it in Fusion 360 and all the parts are either 3d printed with engineering grade materials, CNC milled from 7075 T6 aluminum, or CNC cut from carbon fiber plate. I even CNC cut standard wood props so they fit in the custom folding hub. If you're flying a Falcon, you should make a carbon ehelp. Its really easy to make compared to the XTM5500 all the design files are open sourced, cost is about $2,500 all in if you make yourself and given the limited number of parts you could probably have made for $1000.
did it perform well, any flight footage ?
Yup: th-cam.com/video/oqqEOvN7l8I/w-d-xo.htmlsi=CqUVOgypiUBNz0eD and upgraded footage here: th-cam.com/video/nwmjJ4Opot4/w-d-xo.htmlsi=RzQTbakpNbLYNdLz
لو تكرمت كم عرض الجناح
وطوله ارجو ان تجيب على سوالي
Specs on glider here: www.icaro2000.com/products/hanggliders/laminar/laminar.htm#23 its the 13.1
This is potentially a lot simpler to build than a powered harness, but unless it is cheaper, I much prefer a powered harness instead of a powered wing... Why did you choose this way?
Actually much more complicated to build then a powered harness. I designed and built an ehelp in 6 weeks from CAD to working rig video here: th-cam.com/video/4Z1WWt682bY/w-d-xo.html. It was under powered and I've since added a bigger motor prop combo. Some reasons for glider mount below:
- Thrust line swings around on powered harness. When you move your body unless perfectly coordinated and lined up the thrust line can have major control issues and isn't efficient. I have an LD Explorer (similar to Mosqiuto) if you turn left for example and your feet swing out to the right then the thrust line is driving you into the turn, it kinda feels like you're getting pushed into a spin, backing off motor solves this.
- Can't aerotow with a powered harness as it doesn't fit in standard cart.
- Have p-factor with single large props etc. Twin is counter rotating.
- Need special or modified harness.
Most importantly though the goal of this project was to build a very minimal unit to enable sustained flight for 5-10min to find the 1st thermal and climb out. My main site (cool video here: th-cam.com/video/ycU4ZDrqKA4/w-d-xo.html is just 500ft agl) requires 15-20mph wind for the ridge to work otherwise you need to launch in a really big thermal right at launch which never seems to happen. On a weak wind day with the XTM 5500 I could launch with min of 5mph, and fly to nearest cloud. Further it could allow for scooter towing to be a means to achieve soaring flights.
Neat!
I want this you sent to India Boss
Looks like you could mount that upside down for high drag wings like a Falcon???? Or my Sport 2 175???
Doesn't work on a Falcon. I have a 140 Falcon I purchased to test it on and the chord is too long. You need a high aspect ratio wing to ensure there's enough keel to mount and stay clear of the ground. I built a carbon ehelp that works very well with a Falcon. Here is a link to an old flight th-cam.com/video/4Z1WWt682bY/w-d-xo.html. Since then I've upgraded the motor/prop combo and it can climb to about 1,000-1,500 ft on a charge. I'm in the process of organizing all my CAD files, BOM, code, etc and plan to open source the carbon ehelp design. Also if you inverted my design the thrust line would be well above the center of mass of the glider and likely create major issues.
@@cwallen32 OK,, I figured with the drag of a single surface you could adjust the angle enough, but that would take a lot of trial and, the big word, ERROR to figure out. Best done after launch up high I suppose. AND a willing and able pilot of coarse. Love your ideas and will check out the link you supplied. I live in Arizona and am only a 10 hour H2 pilot, but with all this flat land around me and very few mountain launches that I don't even qualify for yet, this, even after H3 would be a great option to not have to travel for. Especially in the winter when it's cooler to fly but have the inversion layer as a ceiling. UGHhh!!!! LOL Bless you and yours. Hope you much success.
Will it possibly be commercially available? Any idea what the price range might be for something that can be used to take off from flat ground and gain at least some 500m?
Don't plan to make a business out of this project, it just can't compete with my day job. However, may make and sell a few if I get good results, though not sure what I would charge, as its very labor intensive.
You can make an ehelp for about $2-3k which will get you to 500m. Its also a proven design. If you're interested can point you in right direction on this.
Charles Allen I’d love to! Why don’t you post that on a hg forum?
bạn dùng loại vải gì.và có độ dày bao nhiêu
What kind of fabric? Not sure what you mean, could be bad google translate.
Nice setup, did you test fly it? Why not put half of batteries into harness?
The earlier prototype has been test flown, haven't flow with this one yet. Was planning to test it in Florida at the comps. However COVID killed those plans.
Putting batteries in harness isn't ideal for the following reasons:
1. would make wire run too long, would likely need to go to 4awg wire adding additional weight
2. As you increase distance from batteries to ESC it needs to be compensated with capacitors to protect them from voltage spikes caused by inductance in wires. Could add more caps but these are currently the scariest part of the setup.
3. Battery and propulsion unit are perfectly balanced around the hang point. If the batteries are on the harness you would need to add a counter weight in the sail to offset the motor weight by adding an additional 9.2lbs in the sail.
4. Would need to find way to mount batteries to harness which would likely be outside and require modifications to the harness.
Goal was to have unit clip onto any glider with very minor modifications. I drilled 2 holes in my laminar and cut the keel fairing off, however I'll sew a zipper on the keel fairing so I can take it on and off in future.
Flew with it 2 weeks ago. It was a very thermic day which was good as i was able to get up to 3k over launch test but not good to get a feel for effect on glider from power unit vs air. Overall the extra 15.5lbs was very noticeable when ground handling but the glider was fine once in air with power off. Glider was a little skaty under full power but very manageable. One issue I had was props didn't fold back when motors were turned off and flying with 2 windmilling props was like flying with a drogue chute. There's no brake on ESC so I was banking on big springs to pull blades back in which didn't work. Working on a few solutions to this now, but its an easy fix, . I'll post a more detailed update in the coming weeks but bottom line is the setup works but needs to be dialed in.
Hi Charles…. we’ve met and flown together at the ECC meets. I to am working on a twin motor design only it’s mounted totally different from yours. How can I get in touch with you? Nick Caci.
Dude... this is neat. What's the best place to get updates about this project?
I'll likely post an update video to my channel and will send to Davis at the OZ report and he'll likely post. Since making the video I've flown with the unit with positive results. Unfortunately the props won't fold after shutting the motors so I need to move to an ESC with a brake which is a major redesign, however I'm finishing up a mechanical brake as a band aid solution. Plan to fly it this weekend and will post a comprehensive update in the coming weeks. Also plan to post more details on my Carbon Ehelp and will open source all design files.
@@cwallen32 awesome , thanks, looking forward to all that. Good luck!
I don't quite understand, why don't the props fold when you cut power?
Also just for you to consider, I was talking to Miloslav from ultralightdesign.cz/ a while ago, and he mentioned that he's actually electronically slowing down the ramp-up of power when starting the engine to prevent the prop unfolding too fast, hitting the limiter, and over time breaking due to this repeated stress. And I saw how the prop unfolds in person, it was nice and smooth.
Don’t engines mounted on the glider create a risk that, if you add lots of power, the glider may get ahead of you, nose up and stall?
You are connected to glider so the thrust line in relation to the center of mass (glider / pilot combo) is what matters. There's some risk that in turbulence if you go weightless the center of mass would become just the glider and this could result in unwanted pitch changes do to power.
Nice rig. You said 1400Mah, I think you meant 2, 6S 14000mah batteries run in series making 14000mah 12S ? Which motors and what prop size?
Correct 2x6s, there a bunch of other errors in video as well but its not a product promotion more a project overview so didn't feel like reshooting. MAD 180kv drone motors, tried about 6 different motors before settling on these. Props are 19.7x10, however I think I may be able to go as high as 21x12 assuming they are only run in the air.
@@cwallen32 Nice job, those motors are good and your battery choice is good. The higher voltage will run cooler. Keep bumping the prop diameter on the ground until you hit the ESC amp limit knowing it will unload 10% or so in the air.
@@atlantahobbyuavexperts4759 Ha, exactly what I did. Video of my older test stand here: th-cam.com/video/7zbRbz_ZH30/w-d-xo.html. Mfg has motor able to pull 68amps I had it at 61.6amps in test stand (left a little room to be conservative). However, it was in very small room when I tested in big building that allowed air to move around amps dropped to 50amps. So I think in air at 25mph should be able to up prop size. Working on data logging now so I can see amps pulled after flight and adjust accordingly.
I would like to be able to eject batteries in case of battery fire.
So would I but not going to happen with this design and a high performance glider. Very hard to get battery back on keel and strapped in. In 5-15 years when batteries go solid state the risk will go away. However with an ehelp its possible to design an auto-eject system which I'm already working on.
Thanks for responding. I'm watching this tech as I am a new H1, still learning aerotow.
@@adventureswitharizonaart6117 Cool. However this is definitely not for a H1. I've been flying since 1996 and am very careful with my testing and the conditions I'm willing to use in.
How mucho ???
Not selling nor do I have any plans to ever make a business out of it. Plan is to open source the design, created FB page here: facebook.com/groups/904566026835865.
If your flying this design in rough conditions ie slack harness.. the pitch over effect due to thrust line could possible cause a pitch over 🙄
100% disagree. If the hang strap goes slack then the pilot is taken out of the mass equation. i.e. the center of mass would just be that of the glider which would be near the under surface of the glider. The thrust line is currently about 14 inches above the pilot so a few feet below the under surface of the glider. Going slack would cause the glider to pitch up not down.
Also you're missing the whole point of this. If the air is that rough there is no need to fly under power. The end goal is to create a lightweight platform that doesn't have a meaningful effect on flight control in a power off situation but allows the pilot to either scooter tow to a few hundred feet or launch from a training hill and climb to thermal level i.e. 1000ft. It would also be useful as a back up if your about to sink out and want to push to the next thermal before landing. The longer run goal is to design and build an electric powered launch cart so you could safely launch from flat ground, climb up to a thermal and shut the engine and go soar.
How many kw is each motor
Total is 5500 so 5.5kw or 2.25kw per motor. Hence the name XTM 5500
hi, have you make the first flight ?
Yes, 3 flights. I've made refinements after each flight. Plan to have another flight weekend of Sept 26 weather permitting. Bottom line is it works well but is under powered, just sustains zero sink doesn't climb. However its really easy to add more power. I was a 2-3miles away from the tow field on last test flight around 800ft and was able to make it back arriving at about 400ft. I have video and track logs just haven't had time to compile and do a write up.
You really need to put the power unit on your harness.... in the early days 70’s .... there were some fatalities when it was discovered that a high thrust line created pitch instability.... I strongly suggest you change this aspect of your design.
Ha that's the most common response and 100% disagree, core of my design is to get thrust line right, which isn't done right on a powered harness. Also thrust line is only ~6 inches above my center of mass, soarmaster was very high about 6 inches below sail. Please read some of the other comments as this has been addressed. If you have an interest you should read the in depth accident report on the soarmaster link in another comment. Done my research and spoken with pilots who flew the soarmaster. In my opinion the soarmaster was poorly designed over 40 years ago, don't see that as a reason to abandon concept, especially if thrust line can be properly engineered.
Charles Allen I flew a soar master and lost friends to it while trying to develop it..... we then went onto develop trikes that did not exhibit the same problems.... yes there are issues with the thrust attached to a harness, namely rotation, which is manageable..... for your sake I hope you are right....
@@seanwestrope3783 Thanks for the feedback. Given the low power, low weight, and dialed in thrust line I'm optimistic it can be developed safely. Also the goal is not to developed a motor glider but rather a minimal unit to sustain flight to find lift.
@@cwallen32 problem as we discovered was, as by way of illustration, that you wouldn't think of putting a thrust line on the control surface of a conventional wing (flaps, ailerons..etc) nor on the control linkages......these elements effectively work around the thrust line, otherwise the aircraft would be obviously unstable. On a flex wing the whole wing surface and the whole frame is in effect a control surface and the control linkage. For a flex wing the only part of the whole a aircraft that is not part of the control is in fact the pilot (albeit he/she does the controlling). It was this realisation that moved us towards a trike configuration. What you are developing is a self launch HG, which I think is the way forward because it would be more convenient for pilots. You are also now beginning to get the materials and technology to make this practically possible without disproportionately affecting the HG performance. It is exciting what you are trying to achieve but it is also important to understand how and why we got to some of the solutions we adopt today. I wish you every success.
@@seanwestrope3783 Thanks for the thoughtful feedback, much appreciated. To clarify though this is not meant to be a self launch power unit. The required power to get off the ground would be too high to be safe at this stage of development and the flight speed would be too close to stall were there are known issues form the soarmaster. It was originally designed to provide enough power to maintain sustained flight (i.e. zero sink) though I think it should produce 100-200 fpm climb after taking off via another means.
You make a great point regarding power being attached to a control surface. Hence why I'm keeping the power low and don't believe this will work on a low performance glider. One difference between gliders 40 years ago and a modern high performance flex wing is the amount of flex and rigidity. Comparing my falcon to my laminar in terms of flex the falcon is more flexible, likely closer to a 40 year old glider and the keel can really swing around. The keel on my laminar Z9 doesn't swing much and if I go full VG things barely move.
I'm optimistic that if I get the thrust line dialed in there will be a safe envelope of speed, bank angle and pitch that can be flown. Modern electronics are also something didn't exist in the past. Both the remote and power unit have dual core 240mhz processors which I can hook multiple sensors up to. I have a 9 DoF IMU I plan to connect in future which could kill motors if pitch and/or bank angle goes above or below set angles.