*You may be thinking "all this wind tunnel testing and you still got the CG wrong?"* Our wind tunnel studies predicted that the Kingfisher **may** be stable at static margins of 5%, but might experience some nasty neutral point movements and control reversal at high angles of attack, we knew that at 8% static margin the Kingfisher would be flyable. However, increasing the static margin increases the amount of ballast/ weight, and increases trim losses. So, we wanted to find the minimum static margin we could get away with. Hence, the plan was to always start with 5% and slowly increase. As we found, a 7% static margin was necessary to be flyable. For reference, the static margin is a measure of how far the CG is ahead of the neutral point. The neutral point is sort of like the centre of pressure, but is defined as the point where the pitching moment is constant for small (sub 10 degree) angle of attack changes. *3DP SPECS:* We sized the 3DP to match the wing cube loading of the full-size Kingfisher, which is a good indicator of how an aircraft handles because it also takes into account the size. Length = 0.8m (60% scale) Weight = 2 kg Wing loading = ~130 g/dm^2 Wing cube loading = 37 g/dm^3 (vs 39 for the full-size Kingfisher) Powerplant = 70mm 6S EDF Thrust to weight ratio > 1 To maximise TWR and wing loading at the same time (to be as representative of the Kingfisher as possible), the EDF is basically the same size as the fuselage. We had to saw off the front of the EDF to get it to fit inside such a tight package. It looked super clean once integrated!
@@TheMachInitiative Yep. That cg vs stability vs efficiency is a real bitch. Glad you got an estimate in the wind tunnel. Looks like your estimates were pretty close. I’m sure you have already looked into the cp change as it goes transonic. I can’t help you there apart from the obvious of sacrifice sub sonic lift for supersonic stability. Ie, symmetrical shape and airfoil. As always, I’m very impressed with how you kids are going to
That's amazing progress. Hopefully with the log files you can see why it was so twitchy in the air and dial it in. You can easily have a few different profiles setup on a toggle switch to flick between modes that allow you to have minimal input and the fc does most of the work and then slowly swop it so you have all the control. Nice work
Did I misunderstand what was said in the video? Did the professional test pilot you hired on operate only crewed aircraft until now?? Props to him. Flying RC line of sight is a completely different sensory experience without the pilots equilibroception, proprioception and vision essentially functioning as a redundant set of instruments, yet he adapted to that remarkably well! Hats off to him.
Congratulations Guys, you got it airborne! Here's my quids-worth: too low a static margin also lowers the dynamic margin, which can make it wobbly with inertial coupling between pitch and roll oscillations. Also, high alpha's on slender delta configurations like yours (struggled with this myself!) can produce a weird short-period roll oscillation caused by the wing vortices literally battling it out over the upper fuselage forebody - this won't show up in wind tunnel testing as you need freedom in both roll and yaw. I christened this 'wibble' (induced wobble) and at first I mistakenly thought it was some sort of 'Dutch roll' oscillation, which it's tempting to combat using yaw damping. But that could make the 'wibble' worse! Add some roll-rate damping into your flight controller, but only that. Much later into the flight-test programme you can add more functionality. Every 5 degrees of leading-edge sweepback has the same effect as 1 degree of wing dihedral, ergo zero dihedral is over-stable! I've found that combatting this with notable negative wing dihedral ('an-hedral') really helps, even though it feels counter-intuitive. Most manned deltas have anhedral. P.S. we've got a very long launch-rail!
Yooo unrelated thanks for this! I build a lot of slender deltas and I've always wondered why their high-AoA wing rock was so much more pronounced... In your experience, would making a slender delta that was a low-wing affect this at all, e.g. the fuselage acting like a bit of a fence to keep the vortices separate? Or am I picturing it wrong?
I wonder if your pitch stability issues are due to the shape of the nose. It's like a big paddle when it changes angle of attack and I'd imagine you get some airflow coming unstuck leading to messy airflow (flow separation) over the wings and also odd spanwise flow. I reckon I'd be looking at perhaps some stabilisation gyros to dampen the pitch issues as really the shape is about how slippery it is at high speed and not how well it turns... right up until you need to bring her around for another run.
I would try it with increased rudder surface. I've built a few delta's from scratch and found out at higher angles of attack that the wing will block the rudder. I might help to get it more stable. Keep on the good work, I'm enjoying your adventures and design process.
Make the main wing serrated like the younger hawker hunter in production after the prototype. so your kingfisher will fly better in tight turns in the air and land safely without breaking.
Do you plan on not using gear and launching with a slingshot as well? One suggestion I would make is to use a "Dolly", similarly to the me163 komet, which allows the aircraft to take off conventionally without the added weight of retractable landing gear or gear at all. The slingshot also seems to launch the aircraft quite inconsistently and a standard takeoff would provide full control to the pilot.
This is something we are strongly considering. We did some more 3DP flights and the catapult was being very unreliable. Also not sure how well it scales to the full size kingfisher which is 5 times heavier
Since i have no experience with the rc size jet engines, what is the ttwr you are getting out of it and also will it be able to reach mach without afterburners and variable nozzle
From my experience in RC i think you were still needing to move more weight forward. I wouldn't add weight, just shift things. And yes, i saw how the height decreases in the nose, perhaps a compromise of "perfect" aerodynamics might be necessary and do a mod. Back to the old form follows function and pushing the 'guts' forward requires some form thickening. Also, when the time comes, you might consider something ive had good success with on launching large RC models by attaching a launch rack to the roof of a car, driving up to flight speed and doing a release. Ive launched some 4.5 meter wingspan craft that way. (Note that i also used the roof rack first with a pivot without releasing tge bird to check CG and control response tuning. Much better to do than launch with hope then collect pieces into a garbage can)
Awesome work. Still looked tail heavy but I want there. Worried the autopilot (cheap simple version) was not installed to retrieve flight data. (I do that with my toys) Excellent to see this going so well
Top tip: if you have really windy audio there are lots of AI solutions to remove it. The voice can end up sounding a tiny bit odd but it's a lot nicer to listen to!
We tried putting the pilot interview through an AI tool but it sounded really weird - next time when talking on the field we’re going to makesure to wear a microphone instead of relying on the camera audio!
A lot of fighters have ventral fins to help improve high aoa yaw stability. Is this something you've considered? Might be a better way to improve yaw stability at high aoa compared to increasing the size of the vertical tail. I am also wondering if your pitch stability issues are similar to what initially plagued the F-18. A lot of effort went into studying the vortexes generated by the leading edge extensions as they could be inconsistent causing sudden changes in center of lift. Really cool to see your progress!
@@YensR Its worth noting that Wing Cube Loading (mass/area^1.5) is a much better indicator of how an aircraft handles. We tried to match this as closely as possible, so the 3DP has a WCL of 370 g/dm^3 vs 390 g/dm^3 for the full-size aircraft
Any chance of an FPV version? Maybe mod the intake to a divertorless design and put a camera window in the bump? EDIT: Saw your other response about full scale version having analog FPV. Awesome!
Really cool project, one main question so far. How are you planning to land the full size version? It's my understanding that turbines really don't like rough landings.
Great progress guys, Love it!! For the 1/1 scale you intend to “catapult” launch it (bungee cord)? Since it’s going to be very heavy for it’s dimentions, maybe you could try taking it into air with a bigger Rc model; some what the idea with the space shuttle. At least you’ll already have some airspeed and altitude Keep it up guys!! 💪💪💪🔥🔥🔥🔥
I like your thinking of giving the aircraft more static airspeed from the get-go. My initial thought was that it further complicates getting the kingfisher into the air. Requiring additional engineering, fabrication and testing time. And also money. I think making the slingshot/catapult longer for the full-scale model would give the aircraft a longer range to accelerate and maybe also make the acceleration more gradient, reducing the forces upon launch. These are just my 2 cents. I would love to hear other peoples thoughts on this!
We agree we’re never going to compete with 10m+ long unmanned aircraft, engines of that size can get a much greater thrust/ drag. The record we’re going for is for the fastest sub-25kg jet-powered model aircraft - more info here: www.guinnessworldrecords.com/world-records/fastest-remote-controlled-jet-powered-model-aircraft-(rc)#:~:text=The%20fastest%20remote%2Dcontrolled%20jet,difference%20of%2042.251%20km%2Fh.&text=Comments%20below%20may%20relate%20to%20previous%20holders%20of%20this%20record.
Well done! Thanks for the video...nice to see your practice versions working well ( that torque roll on the foamie was crazy!) Keep up the good work! May I ask if the project was successful would you be willing to share the plans and dimensions? I'm sure you wouldn't want anyone plagiarising your hard work at the moment😅
Your model needs to have canards to help stabilize the flight characteristics. I promise you that if you did this, you would not regret it. Just my 40 years of building and flying experience speaking. Great job so far, gentlemen!
The dimensionless wing-cube-loading works out to ~34 just for the EDF demonstrator, that's insane... Respect to your pilot that he was able to keep it in the air and nurse it to a - well, a "gentle crash"! 😁 The fact that it literally started backflipping with the CG "ahead" of the calculated neutral point, even by a few percentage points, makes me wonder if something about the fuselage aerodynamics etc. is throwing off the CG calculation. I've flown a LOT of intentionally-tail-heavy deltas and personally have always found I had to be well into the negative static margin to get such uhhhh... "gleefully" divergent behaviour (admittedly, none of mine have been anywhere near this high WCL!) You mentioned in the pinned comment that the static margin was derived from wind tunnel testing - did you work it out by any other means as a comparison? If yes, did they agree well with the wind tunnel results?
Great looking aircraft! Was it on purpose that you let it stick to the ground while launching? Maybe a detachable undercarrage or sled would do wonders. For landing maybe thin extendable skids? Carry on the great work! Will your 3d files be available?
The launch and landing procedure is something we’re ironing out - clearly for the full-scale flight we’ll need some kind of release mechanism. Ideally we’d run the aircraft along a rail to keep it straight but we’ll see how practical that is to implement. Stopping it from flipping on landing is another challenge we’re working through - extendable skids would add a lot of complexity, we’re hoping the skid shaped fuselage will do the trick. The full-size Kingfisher has sacrificial 3D-printed wingtips which can easily be replaced
@@TheMachInitiative The skids could just consist of a metal strip on a hinge, a spring and a small servo to unlock. After activation they pop out and would just dampen the landing so the nose can't dig in. For the rail you could go with a simple double rail and just slide along with your bungee or a tube with a roller cart. Are you planning on fpv for controlling? At those speeds it will be very hard to see in the sky and from the ground.
When I saw the plastic sheet, I thought it would never work, and it barely did. You won't know if the CG is correct until you fly it inverted. If it climbs, it's tail heavy. You should have to hold a touch of forward stick (down elevator) to maintain altitude in level inverted flight. How many inserts did it devour?
Hi , im not a earospace engineer of any sorts just want to ask a question. Is there a way to calculate if the enige can stall when flying high alpha, the intake looks to be in the vortex zone
Great question! We used two approaches: (1) Computational fluid dynamics during the initial design - this simulates the airflow going through the inlet to look for pressure differences across the engine face, and recirculating regions/ vortices inside the inlet which could lead to stall (2) We then validated the CFD using experimental tests. We attached the inlet to the engine on the test stand, and used some electric ducted fans to push high speed air into the inlet at a high (20 degree) angle while the engine was running, and didn’t observe any stalled.
They do exist - they're called Turbulators, but they aren't common for a number of reasons. 1 - Aircraft fly a lot faster than golf balls, so the flow is normally turbulent without needing any help. 2 - While turbulent flow reduces wake drag, it increases skin friction drag. Streamlined bodies like aircraft tend to have more skin friction drag than wake drag - so turbulent flow usually makes more overall drag on a plane. In fact in a few cases (like the p51 Mustang) special effort is put in to keep the flow laminar, not turbulence, and that helped with that aircraft's particularly long range. Hope that clears things up! -Max
It is something we’d like to do - the issue is we spent a lot of effort designing and testing the aerodynamic shape, and don’t want to risk giving that away to competitors. No promises, but when we do the record attempt we’ll consider it :)
Have you accounted for scale speed? If the plane is flying over 500mph in true speed, then the scale will surely be Mach 3 or something right? Either way, that design isn't suitable. That inlet seems to be acting as an airbrake at the wrong angle of attack.
I think it's definitely doable but I'm wondering if it would be better to curve the inlet around the body more. And have it directly pass over top of the engine for cooling. @@TheMachInitiative
Fellas I think you may need to do slightly more research on the rc hobby side. First off… You had it tailheavy beyond flying, You MUST ALWAYS center your surfaces before you fly, And you need lower rates for higher speeds. This is a cool project wouldn’t wanna see it crash
Thanks for your support of the project and advice - to address some of these points: The change in CG between flights 1 and 3 was only 1cm - wind tunnel tests had shown we may be unstable with the initial cg depending on the margin of error of the experiment, but we wanted to see what we could get away with, as we want to minimise how much ballast we have to put in the big one. The first two flights cemented that we needed a more ballast than we hoped for! Offsetting the elevons was a conscious decision - the delta wing needs 15-20 deg of upward elevon to trim on takeoff/ landing and stop it from rotating. For higher speed flights we’ll defo level them or have a transmitter mode to switch from trimmed low speed deflections, to levelled high speed deflections. Strongly agree on point 3 - we’re going to have multiple transmitter modes to alter the throws at different speeds. The full-size aircraft has split elevons so we’ll only control using the inboard elevons at high-speed for better sensitivity.
The inlet for the engine is too large... the stagnation pressure within will likely cause a compressor stall in a single stage centrifugal flow compressor.
Thanks! Chris made it look easy in the video but the aircraft has a wing cube loading of 37, which is well above the “expert” threshold of 17 - he’s crucial to the operation, none of us would be able to fly it as elegantly as he did - very glad to have him onboard
So gonna toss my two cents in here after 25 years of flying RC sailplanes. Ditch the sling shot launcher. You will continue to have problems getting consistent launches. Single point bungee will serve you much better also two hook placement is critical in you set up having to it well forward will allow for build up speed instead of altitude.
Agreed - it is too unreliable. We’re currently redesigning the launcher and testing a few things out, hence the absence over the last few weeks - we’ll hopefully have a new video soon
I do hope you're aware the current RC speed record is 548mph and held by a GLIDER doing Dynamic Soaring. If you're scared of piloting your machine, imagine doing it in a 50g corner in 60mph winds, just a few meters off the ground ;) ruclips.net/video/0nyYaL0dGAA/видео.html
1st. Congrats 2nd.I told u before and tell you now...its too small. Not matter the cience before the concept, the pilot NEED to see it. More import if the plane is fast.
500+mph already achieved by a RC glider. Achieved by dynamic soaring. So your powered plane is quite slow. Oh and their glider was not weighed in ounces but kilos.
@@arl6565 the gliders can keep this speed up for hours. Something this small jet cannot do. The duration of its flight will be measured in minutes, NOT HOURS.
The gliders can go for hours, as long as they’re on the right slope of a mountain with perfect wind conditions. And they can’t leave the mountain with any meaningful speed. Let these guys have their moment
![Seungmin "그렇게, 천천히, 우리(As we are)" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/kAzmhLHePqU/mqdefault.jpg)
*You may be thinking "all this wind tunnel testing and you still got the CG wrong?"*
Our wind tunnel studies predicted that the Kingfisher **may** be stable at static margins of 5%, but might experience some nasty neutral point movements and control reversal at high angles of attack, we knew that at 8% static margin the Kingfisher would be flyable. However, increasing the static margin increases the amount of ballast/ weight, and increases trim losses. So, we wanted to find the minimum static margin we could get away with. Hence, the plan was to always start with 5% and slowly increase. As we found, a 7% static margin was necessary to be flyable.
For reference, the static margin is a measure of how far the CG is ahead of the neutral point. The neutral point is sort of like the centre of pressure, but is defined as the point where the pitching moment is constant for small (sub 10 degree) angle of attack changes.
*3DP SPECS:*
We sized the 3DP to match the wing cube loading of the full-size Kingfisher, which is a good indicator of how an aircraft handles because it also takes into account the size.
Length = 0.8m (60% scale)
Weight = 2 kg
Wing loading = ~130 g/dm^2
Wing cube loading = 37 g/dm^3 (vs 39 for the full-size Kingfisher)
Powerplant = 70mm 6S EDF
Thrust to weight ratio > 1
To maximise TWR and wing loading at the same time (to be as representative of the Kingfisher as possible), the EDF is basically the same size as the fuselage. We had to saw off the front of the EDF to get it to fit inside such a tight package. It looked super clean once integrated!
You might want to consider a net to catch it on landing XD
@@TheMachInitiative
Yep.
That cg vs stability vs efficiency is a real bitch.
Glad you got an estimate in the wind tunnel.
Looks like your estimates were pretty close.
I’m sure you have already looked into the cp change as it goes transonic.
I can’t help you there apart from the obvious of sacrifice sub sonic lift for supersonic stability. Ie, symmetrical shape and airfoil.
As always, I’m very impressed with how you kids are going to
put a nozzle on that EDF may go faster
ruclips.net/video/jOvyN77rJnA/видео.html
Wow congrats!!! Looked amazing in the air. What a great silhouette. Congrats to the entire team on your successful flight!
Thanks James - we’ll have to get you to the field soon!
When would you guys colab am i just dreaming hehe
Excellent work, can't wait to see you shatter the record!
Awesome video. Congratulations to your entire team on you your successful test flight. Keep up the great work!
Building a super fast RC, cool. I used to build jacked up F-27 Strykers. Ur Kingfisher has what looks like a difficult profile to orient at distance.
That's amazing progress. Hopefully with the log files you can see why it was so twitchy in the air and dial it in. You can easily have a few different profiles setup on a toggle switch to flick between modes that allow you to have minimal input and the fc does most of the work and then slowly swop it so you have all the control. Nice work
Did I misunderstand what was said in the video? Did the professional test pilot you hired on operate only crewed aircraft until now?? Props to him. Flying RC line of sight is a completely different sensory experience without the pilots equilibroception, proprioception and vision essentially functioning as a redundant set of instruments, yet he adapted to that remarkably well! Hats off to him.
Professional RC pilot. 150kg is a…. very small full scale airplane…
Congratulations Guys, you got it airborne!
Here's my quids-worth: too low a static margin also lowers the dynamic margin, which can make it wobbly with inertial coupling between pitch and roll oscillations.
Also, high alpha's on slender delta configurations like yours (struggled with this myself!) can produce a weird short-period roll oscillation caused by the wing vortices literally battling it out over the upper fuselage forebody - this won't show up in wind tunnel testing as you need freedom in both roll and yaw. I christened this 'wibble' (induced wobble) and at first I mistakenly thought it was some sort of 'Dutch roll' oscillation, which it's tempting to combat using yaw damping. But that could make the 'wibble' worse!
Add some roll-rate damping into your flight controller, but only that. Much later into the flight-test programme you can add more functionality.
Every 5 degrees of leading-edge sweepback has the same effect as 1 degree of wing dihedral, ergo zero dihedral is over-stable! I've found that combatting this with notable negative wing dihedral ('an-hedral') really helps, even though it feels counter-intuitive. Most manned deltas have anhedral.
P.S. we've got a very long launch-rail!
Yooo unrelated thanks for this! I build a lot of slender deltas and I've always wondered why their high-AoA wing rock was so much more pronounced... In your experience, would making a slender delta that was a low-wing affect this at all, e.g. the fuselage acting like a bit of a fence to keep the vortices separate? Or am I picturing it wrong?
@@rcbinchicken Absolutely, the Space Shuttle's large fuselage kept the vortices apart. I build an RC shuttle and it never wibbled.
I wonder if your pitch stability issues are due to the shape of the nose. It's like a big paddle when it changes angle of attack and I'd imagine you get some airflow coming unstuck leading to messy airflow (flow separation) over the wings and also odd spanwise flow. I reckon I'd be looking at perhaps some stabilisation gyros to dampen the pitch issues as really the shape is about how slippery it is at high speed and not how well it turns... right up until you need to bring her around for another run.
I would try it with increased rudder surface. I've built a few delta's from scratch and found out at higher angles of attack that the wing will block the rudder. I might help to get it more stable.
Keep on the good work, I'm enjoying your adventures and design process.
what an amazing progress , all the best to the team and kingfisher
Looking forward to see how the Kingfisher will eventually handle, great job :)
That was beautiful. Nice job!
U fellas are inspirational...l;ove the enthusiasm.
Looks awesome! I’ve been following for a little while now and think this is great progress
Congrats guys. Keep up the good work.
Make the main wing serrated like the younger hawker hunter in production after the prototype. so your kingfisher will fly better in tight turns in the air and land safely without breaking.
Do you plan on not using gear and launching with a slingshot as well? One suggestion I would make is to use a "Dolly", similarly to the me163 komet, which allows the aircraft to take off conventionally without the added weight of retractable landing gear or gear at all. The slingshot also seems to launch the aircraft quite inconsistently and a standard takeoff would provide full control to the pilot.
This is something we are strongly considering. We did some more 3DP flights and the catapult was being very unreliable. Also not sure how well it scales to the full size kingfisher which is 5 times heavier
great success!
Nice!
Idea: add contrasting color/pattern to wing surfaces to more easily distinguish top/bottom. For pilot and video observers.
It'd be great to see more practise flights while you're getting ready for the maiden
Since i have no experience with the rc size jet engines, what is the ttwr you are getting out of it and also will it be able to reach mach without afterburners and variable nozzle
It’s got about a 2.5:1 thrust to weight ratio, no afterburner or variable area nozzle!
OMG OMG OMG NEW VIDEO 🎉🎉🎉🎉
:0 woah its much smaller than i was thinking it would be
From my experience in RC i think you were still needing to move more weight forward. I wouldn't add weight, just shift things. And yes, i saw how the height decreases in the nose, perhaps a compromise of "perfect" aerodynamics might be necessary and do a mod. Back to the old form follows function and pushing the 'guts' forward requires some form thickening.
Also, when the time comes, you might consider something ive had good success with on launching large RC models by attaching a launch rack to the roof of a car, driving up to flight speed and doing a release. Ive launched some 4.5 meter wingspan craft that way. (Note that i also used the roof rack first with a pivot without releasing tge bird to check CG and control response tuning. Much better to do than launch with hope then collect pieces into a garbage can)
Awesome work.
Still looked tail heavy but I want there.
Worried the autopilot (cheap simple version) was not installed to retrieve flight data.
(I do that with my toys)
Excellent to see this going so well
Top tip: if you have really windy audio there are lots of AI solutions to remove it. The voice can end up sounding a tiny bit odd but it's a lot nicer to listen to!
We tried putting the pilot interview through an AI tool but it sounded really weird - next time when talking on the field we’re going to makesure to wear a microphone instead of relying on the camera audio!
A lot of fighters have ventral fins to help improve high aoa yaw stability. Is this something you've considered? Might be a better way to improve yaw stability at high aoa compared to increasing the size of the vertical tail. I am also wondering if your pitch stability issues are similar to what initially plagued the F-18. A lot of effort went into studying the vortexes generated by the leading edge extensions as they could be inconsistent causing sudden changes in center of lift. Really cool to see your progress!
would love to test this on a 90mm edf
Great stuff! How does the EDF wing loading compare to the full scale jet powered one?
The wing loading on the 3D print is slightly lower - landing speed is about 40 mph vs 50 mph for the jet-powered one
@@TheMachInitiative that sounds like a good approximation for these flights! Good luck for the big one!
@@YensR Its worth noting that Wing Cube Loading (mass/area^1.5) is a much better indicator of how an aircraft handles. We tried to match this as closely as possible, so the 3DP has a WCL of 370 g/dm^3 vs 390 g/dm^3 for the full-size aircraft
@@TheMachInitiative thank you, that's very interesting, I had not heard of that variant!
Dynamic Soaring already at 550 mph with no engine. Mind blowing
3:00 That plastic sheet really fought against the plane since it wanted to attach to the wings.
Good spot - we need to makesure to pin the sheet down better, or use a more rigid surface
Wow this is amazing, if the propeller one is already going this fast then I can already see the one with the jet engine go 600mph
Only 50% throttle on the EDF as well! It is gonna be fast!
@@TheMachInitiative it was only 50%? no way... it was already fast as hell!
Any chance of an FPV version? Maybe mod the intake to a divertorless design and put a camera window in the bump? EDIT: Saw your other response about full scale version having analog FPV. Awesome!
Really cool project, one main question so far. How are you planning to land the full size version? It's my understanding that turbines really don't like rough landings.
It has a light nose and is tail heavy. Looks like it could use some nose weight to balance it out and would probably fly awesome.
what software have you been using for the stability tests? I mean, you ran a 3d simulated stability test before you printed it?
Great progress guys, Love it!! For the 1/1 scale you intend to “catapult” launch it (bungee cord)? Since it’s going to be very heavy for it’s dimentions, maybe you could try taking it into air with a bigger Rc model; some what the idea with the space shuttle. At least you’ll already have some airspeed and altitude
Keep it up guys!! 💪💪💪🔥🔥🔥🔥
I like your thinking of giving the aircraft more static airspeed from the get-go.
My initial thought was that it further complicates getting the kingfisher into the air. Requiring additional engineering, fabrication and testing time. And also money.
I think making the slingshot/catapult longer for the full-scale model would give the aircraft a longer range to accelerate and maybe also make the acceleration more gradient, reducing the forces upon launch.
These are just my 2 cents. I would love to hear other peoples thoughts on this!
This is a competition you can never win, the multi mach test vehicles are remote controlled. Most jet fighters have flown remote control already
We agree we’re never going to compete with 10m+ long unmanned aircraft, engines of that size can get a much greater thrust/ drag. The record we’re going for is for the fastest sub-25kg jet-powered model aircraft - more info here: www.guinnessworldrecords.com/world-records/fastest-remote-controlled-jet-powered-model-aircraft-(rc)#:~:text=The%20fastest%20remote%2Dcontrolled%20jet,difference%20of%2042.251%20km%2Fh.&text=Comments%20below%20may%20relate%20to%20previous%20holders%20of%20this%20record.
Well done! Thanks for the video...nice to see your practice versions working well ( that torque roll on the foamie was crazy!)
Keep up the good work!
May I ask if the project was successful would you be willing to share the plans and dimensions? I'm sure you wouldn't want anyone plagiarising your hard work at the moment😅
Your model needs to have canards to help stabilize the flight characteristics. I promise you that if you did this, you would not regret it. Just my 40 years of building and flying experience speaking. Great job so far, gentlemen!
The dimensionless wing-cube-loading works out to ~34 just for the EDF demonstrator, that's insane... Respect to your pilot that he was able to keep it in the air and nurse it to a - well, a "gentle crash"! 😁 The fact that it literally started backflipping with the CG "ahead" of the calculated neutral point, even by a few percentage points, makes me wonder if something about the fuselage aerodynamics etc. is throwing off the CG calculation. I've flown a LOT of intentionally-tail-heavy deltas and personally have always found I had to be well into the negative static margin to get such uhhhh... "gleefully" divergent behaviour (admittedly, none of mine have been anywhere near this high WCL!) You mentioned in the pinned comment that the static margin was derived from wind tunnel testing - did you work it out by any other means as a comparison? If yes, did they agree well with the wind tunnel results?
That inlet is going to rip itself to bits, then the bits are going to go through what remains of it.
Great looking aircraft! Was it on purpose that you let it stick to the ground while launching? Maybe a detachable undercarrage or sled would do wonders. For landing maybe thin extendable skids? Carry on the great work! Will your 3d files be available?
The launch and landing procedure is something we’re ironing out - clearly for the full-scale flight we’ll need some kind of release mechanism. Ideally we’d run the aircraft along a rail to keep it straight but we’ll see how practical that is to implement. Stopping it from flipping on landing is another challenge we’re working through - extendable skids would add a lot of complexity, we’re hoping the skid shaped fuselage will do the trick. The full-size Kingfisher has sacrificial 3D-printed wingtips which can easily be replaced
@@TheMachInitiative The skids could just consist of a metal strip on a hinge, a spring and a small servo to unlock. After activation they pop out and would just dampen the landing so the nose can't dig in. For the rail you could go with a simple double rail and just slide along with your bungee or a tube with a roller cart. Are you planning on fpv for controlling? At those speeds it will be very hard to see in the sky and from the ground.
You could also just use a big net and fly into it.
Do one with a pusher and release the stls!
When I saw the plastic sheet, I thought it would never work, and it barely did. You won't know if the CG is correct until you fly it inverted. If it climbs, it's tail heavy. You should have to hold a touch of forward stick (down elevator) to maintain altitude in level inverted flight. How many inserts did it devour?
That's a very thin airfoil there...
Anything to keep the drag down!
I think you should add FPV analog system that will help flying on bigger altitudes and have less drag
We probably won’t be flying at higher altitude due to legal/ practical limitations, but we do have an analogue fpv system on the full-size aircraft :)
In Poland we have max altitude of 120m and it’s hard to see the drone so FPV is good for this
And the analogue has a low delay
Hi , im not a earospace engineer of any sorts just want to ask a question. Is there a way to calculate if the enige can stall when flying high alpha, the intake looks to be in the vortex zone
Great question! We used two approaches:
(1) Computational fluid dynamics during the initial design - this simulates the airflow going through the inlet to look for pressure differences across the engine face, and recirculating regions/ vortices inside the inlet which could lead to stall
(2) We then validated the CFD using experimental tests. We attached the inlet to the engine on the test stand, and used some electric ducted fans to push high speed air into the inlet at a high (20 degree) angle while the engine was running, and didn’t observe any stalled.
You need a muff on your camera mic. :)
What about 2 x angled Tail Fins and Curved Wing Tips for stability.
Zoom..👍👍
I've been curious why I've not seen a plane with golfball type dimples on the entire top of the air craft? Thoughts?
They do exist - they're called Turbulators, but they aren't common for a number of reasons.
1 - Aircraft fly a lot faster than golf balls, so the flow is normally turbulent without needing any help.
2 - While turbulent flow reduces wake drag, it increases skin friction drag. Streamlined bodies like aircraft tend to have more skin friction drag than wake drag - so turbulent flow usually makes more overall drag on a plane.
In fact in a few cases (like the p51 Mustang) special effort is put in to keep the flow laminar, not turbulence, and that helped with that aircraft's particularly long range.
Hope that clears things up!
-Max
6 hrs ago upload and youtube recommended to me...
Winky wonky but I am sure you’ll get hang of it 💪
Drop it from a drone so you don't smash it lol and don't stand so close with radio on takeoff.. Probably failsafe.. 👌👌 Cool project..
Be real cool if you posted the step files so we could make our own ;)
It is something we’d like to do - the issue is we spent a lot of effort designing and testing the aerodynamic shape, and don’t want to risk giving that away to competitors. No promises, but when we do the record attempt we’ll consider it :)
Have you accounted for scale speed? If the plane is flying over 500mph in true speed, then the scale will surely be Mach 3 or something right? Either way, that design isn't suitable. That inlet seems to be acting as an airbrake at the wrong angle of attack.
We’re targeting 570 mph true speed, there is obvs a lot to do before we get there!
I think it's definitely doable but I'm wondering if it would be better to curve the inlet around the body more. And have it directly pass over top of the engine for cooling. @@TheMachInitiative
@@TheMachInitiative hello! Do you still intend to use ArduPilot for those speeds? Does ArduPilot support such speeds?
Fellas I think you may need to do slightly more research on the rc hobby side.
First off…
You had it tailheavy beyond flying,
You MUST ALWAYS center your surfaces before you fly,
And you need lower rates for higher speeds. This is a cool project wouldn’t wanna see it crash
Thanks for your support of the project and advice - to address some of these points:
The change in CG between flights 1 and 3 was only 1cm - wind tunnel tests had shown we may be unstable with the initial cg depending on the margin of error of the experiment, but we wanted to see what we could get away with, as we want to minimise how much ballast we have to put in the big one. The first two flights cemented that we needed a more ballast than we hoped for!
Offsetting the elevons was a conscious decision - the delta wing needs 15-20 deg of upward elevon to trim on takeoff/ landing and stop it from rotating. For higher speed flights we’ll defo level them or have a transmitter mode to switch from trimmed low speed deflections, to levelled high speed deflections.
Strongly agree on point 3 - we’re going to have multiple transmitter modes to alter the throws at different speeds. The full-size aircraft has split elevons so we’ll only control using the inboard elevons at high-speed for better sensitivity.
The inlet for the engine is too large... the stagnation pressure within will likely cause a compressor stall in a single stage centrifugal flow compressor.
If you look at our other videos you’ll see that the inlet on the jet engine version is significantly smaller 😉 this inlet was sized for an EDF.
congratulations and well done hiring Chris. Someone who Flies Fast Jets is deffo who you want on sticks; factually correct statement...
Thanks! Chris made it look easy in the video but the aircraft has a wing cube loading of 37, which is well above the “expert” threshold of 17 - he’s crucial to the operation, none of us would be able to fly it as elegantly as he did - very glad to have him onboard
Super tail heavy.
So gonna toss my two cents in here after 25 years of flying RC sailplanes. Ditch the sling shot launcher. You will continue to have problems getting consistent launches. Single point bungee will serve you much better also two hook placement is critical in you set up having to it well forward will allow for build up speed instead of altitude.
Agreed - it is too unreliable. We’re currently redesigning the launcher and testing a few things out, hence the absence over the last few weeks - we’ll hopefully have a new video soon
I do hope you're aware the current RC speed record is 548mph and held by a GLIDER doing Dynamic Soaring. If you're scared of piloting your machine, imagine doing it in a 50g corner in 60mph winds, just a few meters off the ground ;)
ruclips.net/video/0nyYaL0dGAA/видео.html
True but those planes go at those speeds in a circle meanwhile this plane is suppose to go around 600mph in a straight line which is insane.
Tail heavy, check your CG
Crashed hey, keep trying guys. Maybe put a house brick in this little one to simulate the bigger versions wing loading.
1st. Congrats
2nd.I told u before and tell you now...its too small. Not matter the cience before the concept, the pilot NEED to see it. More import if the plane is fast.
500+mph already achieved by a RC glider. Achieved by dynamic soaring. So your powered plane is quite slow. Oh and their glider was not weighed in ounces but kilos.
congratulations... they can go in a circle fast. whatever. being able to travel from one location to another is far more interesting.
@@arl6565 the gliders can keep this speed up for hours. Something this small jet cannot do. The duration of its flight will be measured in minutes, NOT HOURS.
The gliders can go for hours, as long as they’re on the right slope of a mountain with perfect wind conditions. And they can’t leave the mountain with any meaningful speed. Let these guys have their moment
@@ianturpin9180there’s a huge difference between self powered flight vs unpowered flight, we can have both
@@ianturpin9180 Do you have anything positive to say?
Looks slow