This is so fascinating. Gasoline and Jets definitely have more energy density, but the ease of use with an EDF and low energy density lithium ion battery is quite tempting
Thanks! It's video is great explaining difference between stat. and dinam. thrust, how power of motor is transformed to speed of air, and I understood different electrical turbine and jet motor(speed of air thread) Super!!!🎉 Thanks!!!!
Exactly 👍 thx for the simple explanation and now we know also the difference between trust reflex energy and the toroidal draft energy. The impeller edf is more effective. The combination of it at a high altitude will give the maximum resonance.
can we increase the edf thrust by extending the lenth of ducting ? or adding 2 edfs in one long ducting ? or adding a variable nozzle at the end of a extended ducting ?
Great Video. I have 3 questions: 1) How to increase the thrust? 2) for 5-6 Kg plane, what is the smallest diameter (cheapest) EDF we can use? 3) what does the (Kv) indicates in general? Because I see different values for different EDFs but I don't know what it is about.
Hey Genius Boy, 2 ways to increase thrust. Either spin the fan faster or move up to a larger size fan. For a 5 to 6Kg plane, a 90mm is possible, however you will need some significant power. The kv of a motor indicates how many unloaded RPM per volt the motor can put out.
Hi There, good video!, I am sizing a jet powered plane so I am wondering where did you get your thrust vs. speed data. Did you use a model or do you have experimental data?
hi great video. im thinking of making an electronic "rocket" would i be better to use an edf or use multiple compressor stages to increase static thrust?
Thank for the video. Still, jet engine are much more capable than EDF, since liquid fuel stores more energy for a given weight than electric motors! Also one thing to keep in mind : when you want to increase chimical efficiency of any given reaction envolving air, it's always much more efficient with warm compressed air, more energy is stored to take part into the reaction. EDF are not as sophisticated as turbo jet, so the dramatically lower outlet air speed. Last but not least, the relatively low efficiency of RC turbo jets is due to the fact that their combustion temperature is very low 600°C, that's just a joke compared to the 1700°C of modern jet engines. But it seems some guys around doesn't want you to build weapons from them.. And cost wise most people wouldn't buy a 10000$ RC engine.
@@Frequency369 🤔🤔 yup hydrigen is cool. I've been wondering for long tile if it's an actual solutuon for fkying machines, a friend of mine told me if tou gonna die anyway hydrogen is the way to go!
Wow, actually a good video for once. I often need to explain this when converting foamies to turbine power. My rule of thumb is you need twice the EDF thrust vs turbine thrust to get an equal average flight envelope. For example my 35N Kolibri turbine would equal a 70N EDF, which sort of is a quite hot 12S setup. Still on paper the turbines 35N is actually less than a 6S standard 90mm setup. People have a hard time grasping that. Starting from grass the EDF wins, but as soon as you are of the ground the turbine kills the competition at half the thrust(!)
So if you create a plane that, for instance, has rounded leading edge surfaces designed to create maximum lift and has a way to somewhat sharpen or point the leading edge surfaces to reduce drag you could use a more efficient power source to achieve similar differential thrust beyond a certain speed, correct? I could see a multitude of uses for this idea of reducing drag in-flight, rather than increasing thrust. I'm stuck on the idea of surface tension. If there was a way to get a point of the aircraft between the bonds of molecules of air in front of it, it may potentially create a reduced drag state. Similar to diving into water, my theory is that if you can break surface tension before your body comes into contact with the surface there is a much higher ceiling from which a person can dive safely. Granted, water and air are different in many ways, this might enable what I would term vacuum flight. It would eliminate the need for wings in-flight and create new ceilings of velocity due to the drastic thrust/drag ratio change.
@@RCexplained the only problem with the theory on the extreme end is the idea is chemical propulsion in and of itself. Changing atomic or mollecular bonds not only might be dangerous, but it would require a completely chemically morphing airfoil that does not degrade or accumulate mass. It would need to be designed by someone with more knowledge of physics and chemistry than me. On the less extreme end, a wing that could sharpen it's leading edge mid-flight would be a very possible endeavor for almost anyone with a basic grasp on physics of aerodynamics and a very large wallet. Lol
No worries. The fans have a hard time compressing the air when the nozzle gets smaller and becomes more restricted. Otherwise, if this wasn't the case dynamic thrust could be improved.
@@RCexplainedhope you don’t mind if I jump on this discussion, but as I understand it, a smaller nozzle diameter can increase eflux right? What if you could change nozzle diameter *in flight* , could that allow an EDF aircraft to achieve higher flight speed? You take advantage of near 100% SFA for take off and cruise, but at a point where your craft is nearing the speed the nozzle eflux would allow, the variable nozzle shrinks and increases eflux? Or would that just choke out an EDF at speed and drastically reduce thrust…
RCexplained Why model Gas jet engines produce more thrust than EDFs the same diameter ? Could an EDF reach the same thrust that a Gas jet with a powerful compact electric motor ?
It would be awesome, however an afterburner is not legal in North America. Yes it's possible, however the models would have to be scaled up quite significantly in order to reach that level. Model turbines do not make enough power to push an airplane that fast. You would end up with a very very large radio controlled model.
what is the relationship between nozzle diameter and thrust? That turbine has an optimized nozzle to maximize the dynamic thrust, not static. Thrust, typically, increases in turbine engines as air-speed increases, as there is additional airflow that provides allows for additional fuel to be burned, creating additional power. That's probably not true on model engines, as they don't necessarily have as sophisticated of instruments and ECUs. What I don't get is why are EDF nozzles typically much larger than equivalent turbine engines? Seems to me that an optimized EDF nozzle would be significantly smaller than the inlet of the EDF. Has anyone tested that?
Area of flow and efflux is what contributes to thrust. EDF's have much lower efflux vs a turbojet and to compensate, a larger nozzle is required. The turbine engine in the video has a nozzle diameter of around 94% FSA which is pretty well inline with EDF's. EDF FSA vs nozzle diameter has definitely been tested and optimized for best performance.
Confused I don't get how thrust of EDF goes down with speed of aircraft. A perfect inlet is considered to be a bell mouth inlet with zero losses. I thought that duct losses are worst at zero airspeed and improve with airspeed, needing about 120 mph airspeed before it reaches overcomes duct losses due to ram air being forced into duct system. Rationally it would seem that as an EDF aircraft speed increases the thrust would increase somewhat depending on maximum speed of the aircraft. For example say you are able to measure the thrust force the EDF applies to the airframe in flight and with the aircraft static. It would seem that in flight the faster the model goes the less duct losses the EDF has to deal with, improving with speed.
Airspeed subtracts from the EDF air speed in the formula for thrust. It does make sense when you think of it. An EDF producing 100mph of air would create drag (negative thrust) and slow the plane down if the plane was traveling over 100mph.
@@RCexplained Damn. I guess it's just wishful thinking then that if the EDF was being fed 50mph airstream then it would have less work to do to accelerate that to a 100mph stream so it would be able to then accelerate it to 150mph.
@@AerialRCFun you can design a ducted fan system aimed at higher speeds by reducing the inlet area. It requires balancing the inlet area with the ram pressure at the projected airspeed. It is not a simple task.
Does it make sense to install a larger diameter nozzle on that jet engine so that it pushes back more air at a lower speed? Also, why did they design it like this? It's obvious that no rc plane will reach those efflux speeds, and hence a lot of efflux will be "wasted".
It's not a matter of the design for the turbojet that the manufacture has chosen but rather the nature of a turbojet. This is why turbojet engines are not used for commercial jets but better suited for military jet fighters. For RC using a more efficient jet engine type can drastically increase complexity and cost.
You don't NEED flaps on any RC model. But many pilots use them, as do I. It's all part of the flying RC for me. You might NEED flaps for some flight scenarios, i.e. a short field for takeoff or landings. But generally you won't fly in such situations unless you really just want to use flaps. Flaps in RC models do require a whole set of skills that you may not have initially. But it is fun to learn them.
@@gonzalomorenoandonaegui2052 The simplest way would be to mount the edf in a bed that could slide a small amount and then have a sensor that could measure the push of the EDF in flight and send back telemetry or record to data collector onboard.
Nice video, but please do not mix imperial with metric designations, so if youn use Kilometer per hour, do not referre then to X amount of pounds, you do it in grams, or Newton...
Hi N Ver, thank you for the comment. It may be a difference in where we live, dealing with different units is quite common where I live. (I don't even realize I am mixing units at the time) It looks like North American dealers (largest in NA) mix units in their product details for EDF jets and many other products.
@@RCexplained i understand this is a thing as i live in the uk we are officially metric but we still use imperial and it does my head in as i was only ever taught metric at school yet am forced to deal with imperial because we are still stuck in the past. i feel for the future we all need to all start trying to use only one standard preferably metric when we are talking about stuff like this how we get there is up to everyone who uses these measurements regularly! heck im would be happy to ditch metric if we could all just e=agree to use one standard. i was on ebay looking at some fabric and they where selling it as 1m wide by 20inches long i mean come one people we can do better than this its the 21st century :) either way your video is still helpful and you explain things well so thank you.
yes and no .. efflux is like torque / Horse power seesaw ... you can cone or funnel down then exit , which raises air velocity / hp , but that decreases your low end grunt / torque . if your edf is outside the craft it will create more drag .aero dynamically . in short .. a long skinny top speed world record shaped car with a CONED edf exit would win top speed.... that same car with an UN-coned EDF would be faster 0-20 mph.. cool video tho thanks .. Jet Noise Huge Motors - was here
gps package delivery 🚚 at 800mph or better small 10ft wingspan payload 10 gallons of water in 2 standard 5 gallon buckets fight fires 🚒🔥 with ease ready to reload easily economically friendly also groceries etc and able to travel no fatigue for pilot , and with a radar sensing so no in air collisions ai movement predictions and counter signal sending to make others that are unaware able to avoid it🤔😁
Hi there! I’m designing an ultralight Horten design flying wing and would like to hire you to help with the electric fanjet design. Hope we can get together on an email. Please contact me. Thanks, Giovanni
Great video as usual!
Fuel efficiency and wasted eflux is the reason that modern aircrafts switched from turbo jets to turbo fans
Thanks D H!
This is so fascinating. Gasoline and Jets definitely have more energy density, but the ease of use with an EDF and low energy density lithium ion battery is quite tempting
Thanks! It's video is great explaining difference between stat. and dinam. thrust, how power of motor is transformed to speed of air, and I understood different electrical turbine and jet motor(speed of air thread) Super!!!🎉 Thanks!!!!
Glad it was helpful!
This was highly informative. Great audio quality aswell! Thank you.
Exactly 👍 thx for the simple explanation and now we know also the difference between trust reflex energy and the toroidal draft energy.
The impeller edf is more effective.
The combination of it at a high altitude will give the maximum resonance.
Absolutely!
can we increase the edf thrust by extending the lenth of ducting ?
or adding 2 edfs in one long ducting ?
or adding a variable nozzle at the end of a extended ducting ?
Extending ducting length reduces efficiency as you are adding drag to slow down the airflow.
Great Video.
I have 3 questions:
1) How to increase the thrust?
2) for 5-6 Kg plane, what is the smallest diameter (cheapest) EDF we can use?
3) what does the (Kv) indicates in general? Because I see different values for different EDFs but I don't know what it is about.
Hey Genius Boy, 2 ways to increase thrust. Either spin the fan faster or move up to a larger size fan.
For a 5 to 6Kg plane, a 90mm is possible, however you will need some significant power.
The kv of a motor indicates how many unloaded RPM per volt the motor can put out.
That can work
Hi There, good video!, I am sizing a jet powered plane so I am wondering where did you get your thrust vs. speed data. Did you use a model or do you have experimental data?
Hi Heavy Metal, the static thrust was measured and dynamic thrust was calculated.
Great video man thank you . i have question , how can i measure dynamic thrust of a propeller given rpm and diameter
That guy is awesome 😉
hi great video. im thinking of making an electronic "rocket" would i be better to use an edf or use multiple compressor stages to increase static thrust?
You would be best to use propeller if this can fit the diameter of your design.
Good info.
Thank you Tom
Thank for the video.
Still, jet engine are much more capable than EDF, since liquid fuel stores more energy for a given weight than electric motors!
Also one thing to keep in mind : when you want to increase chimical efficiency of any given reaction envolving air, it's always much more efficient with warm compressed air, more energy is stored to take part into the reaction. EDF are not as sophisticated as turbo jet, so the dramatically lower outlet air speed.
Last but not least, the relatively low efficiency of RC turbo jets is due to the fact that their combustion temperature is very low 600°C, that's just a joke compared to the 1700°C of modern jet engines. But it seems some guys around doesn't want you to build weapons from them.. And cost wise most people wouldn't buy a 10000$ RC engine.
Well maybe when we use hydrogen instead 😁
@@Frequency369 🤔🤔 yup hydrigen is cool. I've been wondering for long tile if it's an actual solutuon for fkying machines, a friend of mine told me if tou gonna die anyway hydrogen is the way to go!
Thank you so very much!
No problem Bob!
Well done!
Thank you!
Wow, actually a good video for once. I often need to explain this when converting foamies to turbine power. My rule of thumb is you need twice the EDF thrust vs turbine thrust to get an equal average flight envelope.
For example my 35N Kolibri turbine would equal a 70N EDF, which sort of is a quite hot 12S setup. Still on paper the turbines 35N is actually less than a 6S standard 90mm setup. People have a hard time grasping that.
Starting from grass the EDF wins, but as soon as you are of the ground the turbine kills the competition at half the thrust(!)
Hi Henke, thank you for the kind words. I'm sure I've come across your posts and builds on the forums.
Both of these can be used in rc planes?
Yes there's videos on this channel.
I did not understand any word you just said, must be cool to be smart like you...
So if you create a plane that, for instance, has rounded leading edge surfaces designed to create maximum lift and has a way to somewhat sharpen or point the leading edge surfaces to reduce drag you could use a more efficient power source to achieve similar differential thrust beyond a certain speed, correct? I could see a multitude of uses for this idea of reducing drag in-flight, rather than increasing thrust. I'm stuck on the idea of surface tension. If there was a way to get a point of the aircraft between the bonds of molecules of air in front of it, it may potentially create a reduced drag state. Similar to diving into water, my theory is that if you can break surface tension before your body comes into contact with the surface there is a much higher ceiling from which a person can dive safely. Granted, water and air are different in many ways, this might enable what I would term vacuum flight. It would eliminate the need for wings in-flight and create new ceilings of velocity due to the drastic thrust/drag ratio change.
You'd have to create models and test your theory.
@@RCexplained the only problem with the theory on the extreme end is the idea is chemical propulsion in and of itself. Changing atomic or mollecular bonds not only might be dangerous, but it would require a completely chemically morphing airfoil that does not degrade or accumulate mass. It would need to be designed by someone with more knowledge of physics and chemistry than me. On the less extreme end, a wing that could sharpen it's leading edge mid-flight would be a very possible endeavor for almost anyone with a basic grasp on physics of aerodynamics and a very large wallet. Lol
Hi, there is a drop in thrust but speed is increasing. So, as per chart we need less thrust when the speed increases? Quite confusing
No. When the airplanes speed increases the fans dynamic thrust decreases. This is undesirable but part of the equation.
where can you get a 70 mm gas turbine please
Any local turbine dealer.
is the jet eflux same as exhaust velocity ?
yes
What would happen if you mount a 90mm edf on a jetturbine .. does the thrust of the edf add up with the thrust of the jetturbine?
If you run them in series, the 90mm fan would starve the turbine. Thrust would not be the perfect sum of the two run on their own.
Great video👍👍👍
Thank You!
Can you alter the nozzle diameter to increase thrust?
Yes, however a larger diameter nozzle closer to no more than 100% FSA does tend to provide highest thrust.
@@RCexplained thanks for responding. Totally not what I expected about the diameter size.
No worries.
The fans have a hard time compressing the air when the nozzle gets smaller and becomes more restricted. Otherwise, if this wasn't the case dynamic thrust could be improved.
@@RCexplained I totally understand now. Good videos. You earned an subscriber. Thanks
@@RCexplainedhope you don’t mind if I jump on this discussion, but as I understand it, a smaller nozzle diameter can increase eflux right? What if you could change nozzle diameter *in flight* , could that allow an EDF aircraft to achieve higher flight speed? You take advantage of near 100% SFA for take off and cruise, but at a point where your craft is nearing the speed the nozzle eflux would allow, the variable nozzle shrinks and increases eflux? Or would that just choke out an EDF at speed and drastically reduce thrust…
RCexplained Why model Gas jet engines produce more thrust than EDFs the same diameter ? Could an EDF reach the same thrust that a Gas jet with a powerful compact electric motor ?
Answered this on the comment you left on this video: th-cam.com/video/mVYfRFzvBQU/w-d-xo.html
so if we use 4 x 70 mm EDFs, that would be able to generate enough thrust for 8 lb object?
A drone will be well-suited for that
Why no afterburner on these small planes? Also is it possible for an rc plane to go supersonic like the real thing?
It would be awesome, however an afterburner is not legal in North America.
Yes it's possible, however the models would have to be scaled up quite significantly in order to reach that level. Model turbines do not make enough power to push an airplane that fast. You would end up with a very very large radio controlled model.
@@RCexplained I wonder what is the smallest size of plane you could make go super sonic. 🤔
@@LawrenceTimme no rc plane has ever gone that fast. its too dangerous also
@@logiknotlogic6586 it's clearly not that it's dangerous that is the problem. There are loads of planes that go super sonic.
what is the relationship between nozzle diameter and thrust? That turbine has an optimized nozzle to maximize the dynamic thrust, not static. Thrust, typically, increases in turbine engines as air-speed increases, as there is additional airflow that provides allows for additional fuel to be burned, creating additional power. That's probably not true on model engines, as they don't necessarily have as sophisticated of instruments and ECUs.
What I don't get is why are EDF nozzles typically much larger than equivalent turbine engines? Seems to me that an optimized EDF nozzle would be significantly smaller than the inlet of the EDF. Has anyone tested that?
Area of flow and efflux is what contributes to thrust. EDF's have much lower efflux vs a turbojet and to compensate, a larger nozzle is required. The turbine engine in the video has a nozzle diameter of around 94% FSA which is pretty well inline with EDF's.
EDF FSA vs nozzle diameter has definitely been tested and optimized for best performance.
Confused I don't get how thrust of EDF goes down with speed of aircraft. A perfect inlet is considered to be a bell mouth inlet with zero losses. I thought that duct losses are worst at zero airspeed and improve with airspeed, needing about 120 mph airspeed before it reaches overcomes duct losses due to ram air being forced into duct system.
Rationally it would seem that as an EDF aircraft speed increases the thrust would increase somewhat depending on maximum speed of the aircraft. For example say you are able to measure the thrust force the EDF applies to the airframe in flight and with the aircraft static. It would seem that in flight the faster the model goes the less duct losses the EDF has to deal with, improving with speed.
Airspeed subtracts from the EDF air speed in the formula for thrust. It does make sense when you think of it. An EDF producing 100mph of air would create drag (negative thrust) and slow the plane down if the plane was traveling over 100mph.
@@RCexplained Damn. I guess it's just wishful thinking then that if the EDF was being fed 50mph airstream then it would have less work to do to accelerate that to a 100mph stream so it would be able to then accelerate it to 150mph.
@@AerialRCFun you can design a ducted fan system aimed at higher speeds by reducing the inlet area.
It requires balancing the inlet area with the ram pressure at the projected airspeed.
It is not a simple task.
Does it make sense to install a larger diameter nozzle on that jet engine so that it pushes back more air at a lower speed? Also, why did they design it like this? It's obvious that no rc plane will reach those efflux speeds, and hence a lot of efflux will be "wasted".
It's not a matter of the design for the turbojet that the manufacture has chosen but rather the nature of a turbojet. This is why turbojet engines are not used for commercial jets but better suited for military jet fighters. For RC using a more efficient jet engine type can drastically increase complexity and cost.
@@RCexplained As in, a turbofan for example?
Yes exactly.
@@RCexplained for a vtol plane is it better to have 2 edfs or larger traditional prop setup?
@@FirstLast-tx3yj prop is more efficient
Where we buy jet engine sir
There's many places depending on where you are located. Google the brand of turbine that you are interested in and find a dealer close to you.
remember one thing repair and maintenance of a turbine engine is a nightmare...
What makes it a nightmare?
@@RCexplained the cost of repair... and spare parts
Do we need flaps in 2-2.5kg plane
I haven't flow an airplane yet(not saying its always like this) that absolutely requires flaps.
The answer to the question depends on the plane.
Depends on landings, if u have a short space use flaps. If not try not to use them, flaps can cause instability on certian models.
You don't NEED flaps on any RC model. But many pilots use them, as do I. It's all part of the flying RC for me. You might NEED flaps for some flight scenarios, i.e. a short field for takeoff or landings. But generally you won't fly in such situations unless you really just want to use flaps. Flaps in RC models do require a whole set of skills that you may not have initially. But it is fun to learn them.
How can you messure thrust in flight ?
What would you be using this in flight thrust value for?
@RCexplained I don't know I'm not in the RC world, I'm an aviation entusiast and I've always wandered how could they measure thrust in flight
@@gonzalomorenoandonaegui2052 The simplest way would be to mount the edf in a bed that could slide a small amount and then have a sensor that could measure the push of the EDF in flight and send back telemetry or record to data collector onboard.
Nice video, but please do not mix imperial with metric designations, so if youn use Kilometer per hour, do not referre then to X amount of pounds, you do it in grams, or Newton...
Hi N Ver, thank you for the comment. It may be a difference in where we live, dealing with different units is quite common where I live. (I don't even realize I am mixing units at the time)
It looks like North American dealers (largest in NA) mix units in their product details for EDF jets and many other products.
@@RCexplained i understand this is a thing as i live in the uk we are officially metric but we still use imperial and it does my head in as i was only ever taught metric at school yet am forced to deal with imperial because we are still stuck in the past. i feel for the future we all need to all start trying to use only one standard preferably metric when we are talking about stuff like this how we get there is up to everyone who uses these measurements regularly! heck im would be happy to ditch metric if we could all just e=agree to use one standard. i was on ebay looking at some fabric and they where selling it as 1m wide by 20inches long i mean come one people we can do better than this its the 21st century :) either way your video is still helpful and you explain things well so thank you.
What must be the weight of our airplane
In 70 mm ducted fan
Around 2-2.5kg with battery pack would be a good target. There are a lot of dependencies with this number.
yes and no .. efflux is like torque / Horse power seesaw ... you can cone or funnel down then exit , which raises air velocity / hp , but that decreases your low end grunt / torque . if your edf is outside the craft it will create more drag .aero dynamically . in short .. a long skinny top speed world record shaped car with a CONED edf exit would win top speed.... that same car with an UN-coned EDF would be faster 0-20 mph..
cool video tho thanks .. Jet Noise Huge Motors - was here
thanks JNHM!
250 mm
gps package delivery 🚚 at 800mph or better small 10ft wingspan payload 10 gallons of water in 2 standard 5 gallon buckets fight fires 🚒🔥 with ease ready to reload easily economically friendly also groceries etc and able to travel no fatigue for pilot , and with a radar sensing so no in air collisions ai movement predictions and counter signal sending to make others that are unaware able to avoid it🤔😁
Hi there! I’m designing an ultralight Horten design flying wing and would like to hire you to help with the electric fanjet design. Hope we can get together on an email. Please contact me.
Thanks,
Giovanni
Contact info -email, is on the about page.
Background too dark
Bro you look like skinny Tom Brady lol