You need to make sure your force measurements and RPM measurement happen simultaneously. Also, peak torque almost never happens at the same RPM as peak power. Having finer control over the braking force applied would be nice. What about making an electronic brake using a BLDC, a three phase rectifier and a rheostat. Another option would be a pump (fixed displacement) attached to the crankshaft and a needle valve. The body of the motor or the pump would be mounted to the arm that goes to the scale. You would probably need one support bearing at the opposite end of the motor or pump. By varying the brake force the speed of the engine could be controlled at WOT and if the engine speed is not changing then the torque generated by the engine is the same as the torque absorbed by the brake. Take a reading and adjust the brake to change engine speed in 1000 rpm increments. You could develop a whole torque curve this way and then calculate horsepower.
Absolutely what I was thinking - a BLDC motor as a generator connected to a load. Measure RPM, current and voltage using an arduino and a few suitable modules and you can get a propper dyno curve.
@@lewistaylor863 You can't measure power directly from the output of the motor. The efficiency curve is unknown. You use the motor as a brake and measure force using the scale while measuring RPM using the tach. This is how real dynos (load based) work only they use a load cell or torque transducer instead of a scale, but really they are the same thing. The scale is going to have a load cell in it. The BLDC motor is only to apply a load to the engine, you waste the electrical energy as heat in the rheostat/potentiometer. Another option may be a mountain bike disc brake if you were looking for an all mechanical solution. For the cable based ones it should not be too hard to rig up a screw based tensioner that would apply tension to the cable precisely to actuate the brake to control the engine speed. Warped Perception did something to this on his turbo see "thru" engine videos, but he used a motorcycle brake or something similar because the engine is much more powerful than a hobby engine. It would destroy a mountain bike brake.
No need for a BLDC, just a regular, off the shelf permanent magnet DC motor, with a loading resistor and potentiometer then measure the volts and amps for your power output. With the pot you can have much finer load control then a wingnut on a wooden bar. 746W to 1 Hp or very small fractions there of for this one.
There is a misconception in this attempt of yours to measure the torque the engine is producing. When you clamp the crankshaft until it stalls, you are measuring all the inertia of the engine to brake to a complete stop after reaching the 6500+rpm. To measure the actual torque the engine is producing you need to progressively clamp the crankshaft axle until you reach the steady state condition. The value measured will then be the actual torque that your engine is producing. Cheers and keep up with the awesome work you are doing!
Could you please explain it more detailed? I see no difference between the modus operandi of Johnny and what you describe. If you could please find other words to stress the difference ??? Thank you...
@@klausbrinck2137 the difference between what I described and what he did in this video is basically this: In his test, you imagine a kid going fast with a bike and you are standing still in front of him. When he hits you, your resistance is there to brake him to a complete stop. Meaning: you are absorbing all the inertia, plus the torque he was producing. The way I described: You are going in the same direction as the kid is going, at the same speed. However you are applying a brake to only the power/torque the kid is producing to keep the bicycle going. In other words, the inertia is canceled because both of you are moving together. The only measurement you will do is the braketorque necessary to maintain the steady state condition of speed you were in the beginning of the test. This is how we measure the engine power and torque at the industry. I am an powertrain calibration engineer at an European carmaker, btw. :) If you still have any questions, let me know!
@@vsilvanivs I understood very well when you said, that he has to measure the torque while excluding the motor-inertia. But I do not understand how he can, poceedualy, reach this target (always with simple means, of course ). I do not understand what to do to "progressively clamp the crankshaft axle until you reach the steady state condition". He alredy used the clamp incrementaly/progresively... And how do one notices if the "steady state condition" was reached, what phenomenon is then to be observed, in order to say that "steady state condition" was reached?
I am a dyno technician. And i have never thought to test rc engines like this, this is smart! This is a "load cell" dyno. How about an electric motor or something to provide resistance?
elec magnet could give it resistance .. he could make a small steel flywheel then outside have a wire coil when powered would give resistance to the engine ..
Now THAT is a nice contraption. Real data from real measurements. Kudos! PS: Power measurement and calculations are part of my profession. Here's a few tips: What you were measuring now was peak torque, and peak torque is always WELL below peak HP. Second thing that went wrong, is that with full throttle, if you bog down the engine, such a simple carb will most definitely not hold mixture, so your actually measured value will not represent what the engine is capable of. Richen up your HS needle a bit and I am pretty sure you will see higher torque values right before stalling. Reason is, dropping RPM reduces intake vacuum, and that reduces fuel draw, and your mixture will lean out because that throat diameter is designed for 10+K, and you are running only 6K. Now, your peak HP will be around 10, maybe 11 K So if you want to know your peak HP, set the brake for around 10K RPM, then peak the needle and if necessary readjust the brake to maintain around 10K. Now try to get torque readings in steps of 200 RPM between 10 and 11 K, and I am pretty confident that you will see higher HP numbers. Realistically, I do not expect 0,5 hp, but 0,4 should definitely be within the range of what is possible. My own 5 cc fourstroke runs on gasoline (less power than Methanol) and manages about 0,3 HP @ 9,5K On methanol, 0,35~0,4 should be absolutely possible.
ΓιάννηQ μπράβο για τις φοβερές κατασκευές σου, εξαιρετική δουλειά με πολλές λεπτομέρειες και αποτέλεσμα. Συνέχισε να μας εμπνέεις μικρούς και μεγάλους!!!!!
I always enjoy and share your videos since I've been in the hobby of radio-controlled 4 over 30 years and wish I had the equipment our friend here has. Enjoy your RC cars my friends and stay safe with this virus. RC4LIFE 👍👍😎💙😀
Great job, i've wanted to see a dyno for awhile. can you use a R/c Disc brake for better control of drag? (so tightening wing nut doesn't effect reading) and i would love to know if your exhaust mods add power, and i would definitely love to see some numbers from your Blower(s). thanks for the video.
I'm trying to design my own RC Dyno for bench testing 1/5 electric RC. I will be using gravity rollers mounted to a frame. there will be a pair of rollers between each wheel and I want to be able to adjust the resistance of the rollers but do not know what I need in order to also measure the resistance of the roller to create a "load" on the RC. I would also want to be able to capture the wheel RPM and eHP under the specific load. What is this type of attachment called and where could I find a power meter/analyzer like this? I need help and you are a genius with this stuff! My Goal is to be able to see how fast my RC will go under a specific load of resistance. And knowing the actual eHP output would be also very helpful since rated output is usually not even close to actual power output. Thanks!
One of the things I noticed that make power is the heat range of the glow plug, it’s the same as to advancing or regarding ignition. Most useful when using high nitro content fuels.
@JohnnyQ90 Did you do the same valve thing on this engin... i know for sure, the valves dont close properly on these engines... I had to mod mine to make the valves close properly...?
Es es hermoso Tu arte me haces llorar cada vez que me hablas lo que estás haciendo no puedo comprender tanta maravilla No tengo más que agradecimiento Gracias por todo amor que nos obsequia y locas con ternura jamás volveré a ver al metal como una cosa muerta si no como que me grita para revivir
A significant portion of the engine's output may be lost to heat at the wood/metal interface. A lot of people have suggested an electric motor as a load, I think it's a good idea too. The trick will be calibrating it. Possible calibration procedure: - attach a pulley to the motor - wrap a string around it several times - tie a known mass to the string - drop the mass off the table The falling mass will provide a constant known torque. (mass * pulley radius * acceleration of gravity) If you record the drop with a camera, and have a meter stick behind the mass, you can measure the acceleration and velocity of the system. The input energy can be easily calculated using the distance the hanging mass fell. There's a few more math steps after that, but nothing too crazy.
Interesting! Works very well for a proof of concept. I think if you were looking to do an upgrade at any point, a road bike brake disk and caliper would make a more robust and sensitive system. Also, you couldn't need to get so close to the rotating assembly.
There is a bit of inaccuracy due to you having to screw those in, it does offset the result a little bit. But still love the video, looking forward for more.
If you're after a mini-dyno, another interesting thing to look at would be an eddy current brake - using the lorentz force as a brake. It's substantially more tuanble than a direct mechanical brake. A spinning disc of aluminium within a strong magnetic field produces eddy currents within the aluminium, the eddy currents themselves also produce a magnetic field that opposes the rotation of the disc (which is the braking mechanism), the result is a torque transfer to the electromagnets, and heat in the aluminium. A few ways to attack this in your application would be: (1) to get a bunch of neodymium magnets and modulate their proximity to the disc, though the torque would need to be measured through the structure that holds the magnets as well, which complicates the construction difficulty. (2) to get a bunch of electromagnets off eBay, and modulate the current within them with (an adjustable) constant current power supply - this may be easier to facilitate the torque measurement, but would likely cost more if you don't already have the supporting equipment. Though it is my preferred solution, as I've been designing a system like this in my own endeavours (with 50cc engines) because (if you're ok with microcontrollers/etc...) you'll be able to perform basic run-and-hold tests with an RPM feedback into a microcontroller. The microcontroller would allow the engine to run to X rpm, and then actively track and adjust the electromagnets to prevent it going any higher (thus allowing the engine to run under full load without revving out). With a bit more development after that, you'll be able to do full dyno runs and graph the results. (3) use a brushless DC motor to generate power. By directly hooking up a motor (as a generator) and varying the electrical load on the generator. You would want to measure the torque transfer on the generator chassis and RPM, don't even worry about measuring the electrical output power to gauge input power (though it might help to confirm your findings) - using motors as generators is notoriously inefficient and the output electrical power wouldn't be an accurate number.
Check if that mdf has constant friction/temperature. Seems like it could adjust more gracefully. Maybe larger diameter shaft and something else for braking material between metal/mdf torque arm?
Your measurement of the arm should have been from shaft centre to the point of contact with the scale. A pointy-er pointer would have been better to keep control of the point of contact better as well. A pump or a eddy current brake is going to be the only thing that’s going to give you anything like a reliable result or a situation where you can hold the load long enough to read the scale. Did you read my comment on the centrifugal supercharger? A plenum could be the solution there. Really nice machining work, you are very patient and skilled. One of my favourite channels.
When you are using horse power as a unit, could you please also show the value in watts? It would make so much more sense to me, as these engines are more comparable to small electric motors than big IC-engines.
This setup seems more suited for a static load like measuring the force it takes to break something. Im guessing real dynos have rollera for a reason so you can see how the engine behaves at different rpms
You may want to change your center shaft to a larger diamater. This will decrease sensitivity to clamping and increase surface area allowing for more mental volume to absorb heat a little better. The prony brakes I have used typically have a hollow cavity inside the metal part to allow for adding watter to help with cooling.
Nice to see that you made sure to talk about the limitations of your experiment! Make sure to take into account the flex in the wood and the printed plastics too, shouldn't be too difficult for your brain to comprehend I don't think. ;) Wouldn't it also make more sense to hook a slipper clutch up to this instead of using the wood as it's not the most "grippy" of materials? I guess that would also introduce more variables than it's worth. I'm with Blase, when are you making an alignment machine? I bet you have something crude to deal with that aspect that works quite well!
I would suggest making a small disc brake setup to load the engine with and mount the cable or servo actuated brake on the lever arm to push on the scale. You'll be able to load the engine without directly touching the arm and affecting the measurements. Also it'll involve some cool machining and fabrication.
Your math is off. Hp= tq x rpm / 5252 Using the force measured at 3:57 - 3oz @ 1/2 ft = 6 oz/ft or .375 lb/ft .375 x 6600 / 5252= .471 hp. Great work and thank you for the quality content.
Nice build. I have herd stories of professional racers using 10% nitro fuel in races when 20% is the norm. I think they said that they were competitive because they increased the engine's compression to compensate.
Suggestion: Instead of using wing nuts and possibly adding weight to the scale with your fingers touching the wing nut. You could mount a high torque servo in some fashion to the brake and then use use a simple dial adjustment to clamp down on the brake for real precise braking and measurement. Just an idea I came up with watching it.
This guy is about to have a whole rc car garage, what's next an alignment machine?
I do
I guess next should be a wind tunnel, just in case it is needed 😁
😂😂😂
Water bench or fish tank works best.
no, balance machine is better
There's nothing quite like the hiss of tooling metal. So satisfying.
Not when you here it all day or it starts squeaking from dull tools
@@alexrogers9086 “Hear”
@@leopretorius6282 aye you knew what I meant.
instablaster.
Self integrity is just one of the reasons I enjoy your channel. Thank you.
Johnny's saw struggled for a sec on that second cut.
Next episode: 4 stroke wood saw. Brand new supercharger.
Looks like it did fine to me, cut straint and he's ramming that board through
Lol... could push faster with more powahhh! My original comment wasn't meant to be literal. Just a fun thought
@@krystophm1730 more power arrrrr arrrrr arrrr 🤣
You need to make sure your force measurements and RPM measurement happen simultaneously. Also, peak torque almost never happens at the same RPM as peak power.
Having finer control over the braking force applied would be nice. What about making an electronic brake using a BLDC, a three phase rectifier and a rheostat. Another option would be a pump (fixed displacement) attached to the crankshaft and a needle valve. The body of the motor or the pump would be mounted to the arm that goes to the scale. You would probably need one support bearing at the opposite end of the motor or pump.
By varying the brake force the speed of the engine could be controlled at WOT and if the engine speed is not changing then the torque generated by the engine is the same as the torque absorbed by the brake. Take a reading and adjust the brake to change engine speed in 1000 rpm increments. You could develop a whole torque curve this way and then calculate horsepower.
Absolutely what I was thinking - a BLDC motor as a generator connected to a load. Measure RPM, current and voltage using an arduino and a few suitable modules and you can get a propper dyno curve.
@@lewistaylor863 You can't measure power directly from the output of the motor. The efficiency curve is unknown. You use the motor as a brake and measure force using the scale while measuring RPM using the tach. This is how real dynos (load based) work only they use a load cell or torque transducer instead of a scale, but really they are the same thing. The scale is going to have a load cell in it. The BLDC motor is only to apply a load to the engine, you waste the electrical energy as heat in the rheostat/potentiometer.
Another option may be a mountain bike disc brake if you were looking for an all mechanical solution. For the cable based ones it should not be too hard to rig up a screw based tensioner that would apply tension to the cable precisely to actuate the brake to control the engine speed.
Warped Perception did something to this on his turbo see "thru" engine videos, but he used a motorcycle brake or something similar because the engine is much more powerful than a hobby engine. It would destroy a mountain bike brake.
Just use a pulley and a weight lmao
No need for a BLDC, just a regular, off the shelf permanent magnet DC motor, with a loading resistor and potentiometer then measure the volts and amps for your power output. With the pot you can have much finer load control then a wingnut on a wooden bar. 746W to 1 Hp or very small fractions there of for this one.
@@inothome You're right. I just figured he already had a big enough brushless motor.
There is a misconception in this attempt of yours to measure the torque the engine is producing.
When you clamp the crankshaft until it stalls, you are measuring all the inertia of the engine to brake to a complete stop after reaching the 6500+rpm.
To measure the actual torque the engine is producing you need to progressively clamp the crankshaft axle until you reach the steady state condition. The value measured will then be the actual torque that your engine is producing.
Cheers and keep up with the awesome work you are doing!
Shut up.
@@M80Ball Why should he shut up? if what johnny does it wrong, you can be sure he also wants to do it right.
Could you please explain it more detailed? I see no difference between the modus operandi of Johnny and what you describe. If you could please find other words to stress the difference ??? Thank you...
@@klausbrinck2137 the difference between what I described and what he did in this video is basically this:
In his test, you imagine a kid going fast with a bike and you are standing still in front of him. When he hits you, your resistance is there to brake him to a complete stop. Meaning: you are absorbing all the inertia, plus the torque he was producing.
The way I described:
You are going in the same direction as the kid is going, at the same speed. However you are applying a brake to only the power/torque the kid is producing to keep the bicycle going. In other words, the inertia is canceled because both of you are moving together. The only measurement you will do is the braketorque necessary to maintain the steady state condition of speed you were in the beginning of the test.
This is how we measure the engine power and torque at the industry. I am an powertrain calibration engineer at an European carmaker, btw. :)
If you still have any questions, let me know!
@@vsilvanivs I understood very well when you said, that he has to measure the torque while excluding the motor-inertia. But I do not understand how he can, poceedualy, reach this target (always with simple means, of course ). I do not understand what to do to "progressively clamp the crankshaft axle until you reach the steady state condition". He alredy used the clamp incrementaly/progresively... And how do one notices if the "steady state condition" was reached, what phenomenon is then to be observed, in order to say that "steady state condition" was reached?
Allways clean and tidy, never make a mess, nice to watch
One of your simplest creations yet still works awesome!
Love the way you set all this up. Bravo my friend. You are teaching me new things as well. 👏👏👏👏👏👏
Glad to you see finally did this to test engine performance.
Very cool! Can't wait to see more engines get tested 🙂
I am a dyno technician. And i have never thought to test rc engines like this, this is smart!
This is a "load cell" dyno. How about an electric motor or something to provide resistance?
Yes I was thinking the same.
A BLCD with a VESC in regenerative braking mode where you increase gradually the braking torque.
More repeatable maybe...
@@bensthingsthoughts or a flywheel geared right up mounted on the arm
@@bensthingsthoughts or just a DC motor hooked up to a potentiometer for variable resistance?
Electromagnet, not a motor
elec magnet could give it resistance .. he could make a small steel flywheel then outside have a wire coil when powered would give resistance to the engine ..
Love seeing your projects keep up the great work!
Wow no intro or nothing it’s just straight into action, how good.
Integrity is So Rare in CZcams Videos. Thanks!
I've been wondering how to make a small scale dyno for a while now.
Great job.
NICE!!! I just got my FS S100!!
Morning Johnny
Tiny engines are so cool
I needed this today!!!!
That is very simple very genius design. congratulations!
Amazing video as usual!
Now THAT is a nice contraption. Real data from real measurements. Kudos!
PS: Power measurement and calculations are part of my profession. Here's a few tips: What you were measuring now was peak torque, and peak torque is always WELL below peak HP.
Second thing that went wrong, is that with full throttle, if you bog down the engine, such a simple carb will most definitely not hold mixture, so your actually measured value will not represent what the engine is capable of.
Richen up your HS needle a bit and I am pretty sure you will see higher torque values right before stalling. Reason is, dropping RPM reduces intake vacuum, and that reduces fuel draw, and your mixture will lean out because that throat diameter is designed for 10+K, and you are running only 6K.
Now, your peak HP will be around 10, maybe 11 K
So if you want to know your peak HP, set the brake for around 10K RPM, then peak the needle and if necessary readjust the brake to maintain around 10K.
Now try to get torque readings in steps of 200 RPM between 10 and 11 K, and I am pretty confident that you will see higher HP numbers. Realistically, I do not expect 0,5 hp, but 0,4 should definitely be within the range of what is possible.
My own 5 cc fourstroke runs on gasoline (less power than Methanol) and manages about 0,3 HP @ 9,5K
On methanol, 0,35~0,4 should be absolutely possible.
Wow I would really want to have one for my homemade RC cars!!
You can make one using a Dough roller, headphones and RC Dyno software a guy made. And you have a working dyno with display. Cheers
Wow,VERY interesting and unique idea here!!! Thanks for posting this one JohnnyQ90!!!
Friday afternoon, good bowl and a JQ90 video, I am all set!
Very hardwork dude
ΓιάννηQ μπράβο για τις φοβερές κατασκευές σου, εξαιρετική δουλειά με πολλές λεπτομέρειες και αποτέλεσμα. Συνέχισε να μας εμπνέεις μικρούς και μεγάλους!!!!!
realy cool idea!!!👍🏼😉👌🏼
Would really like to see more of this
great idea
Yep we gotta see more testing. Plus the testing on your engine upgrades.
Great idea👍
Απλα δεν υπάρχεις!Οτι και να πω ειναι λιγο!Τελεια δουλειά!!!
Great idea
I would love to see this done with your rotary motors when you have the correct fuel.
Totally agree w/you buddy cause our friend here got mad Skillz ! 👍👍 RC4LIFE 💙
It's not unfair, it's a valid measurement as long as you use it your own engines to see improvements.
Always a good day when when a of yours video is out. Awesome work as always, keep it up 💪
Thanks for the comment!
Nice job bro.
That’s awesome
The Amazing skill...
Already 20 comments after a minute!! 😲
Love the vids bro.... keep up the great work!!
Nice very smart
I'm glad I stayed late 🔥🔥🔥
I hope you Dyno the Turbocharged twin cylinder next!! awesome Video
I always enjoy and share your videos since I've been in the hobby of radio-controlled 4 over 30 years and wish I had the equipment our friend here has. Enjoy your RC cars my friends and stay safe with this virus.
RC4LIFE 👍👍😎💙😀
Just amazing 👍 it
Keep going!
Excellent video, my friend respect from Venezuela.💯👍🤘💯💯💯
Can you do it on your twin 2 stroke nitro engine? I was hoping that you will do an rc 1/10 truck build using the engine
Great job, i've wanted to see a dyno for awhile. can you use a R/c Disc brake for better control of drag? (so tightening wing nut doesn't effect reading) and i would love to know if your exhaust mods add power, and i would definitely love to see some numbers from your Blower(s). thanks for the video.
I'm trying to design my own RC Dyno for bench testing 1/5 electric RC. I will be using gravity rollers mounted to a frame. there will be a pair of rollers between each wheel and I want to be able to adjust the resistance of the rollers but do not know what I need in order to also measure the resistance of the roller to create a "load" on the RC. I would also want to be able to capture the wheel RPM and eHP under the specific load. What is this type of attachment called and where could I find a power meter/analyzer like this? I need help and you are a genius with this stuff! My Goal is to be able to see how fast my RC will go under a specific load of resistance. And knowing the actual eHP output would be also very helpful since rated output is usually not even close to actual power output. Thanks!
For testing the torque, would it not make more sense to use a bearing so testing is a little more consistent?
Could you finger on the wing nut be causing a lower reading..?
Very interesting!
Will the diameter of the axle being clamped affect the torque?
Hey, you are part of my inspiration for engineering school. Keep it up!
0:07 Can you record a thermal image of this please ? How hot are that blade like thing and the cylinder ?
Great job man!!
Your videos really helped me a lot
:) :) :) :) :) :) :) :) :)
it would be super intersting to see how much of a difference the right fuel makes
Oh, a prony brake. Neat.
One of the things I noticed that make power is the heat range of the glow plug, it’s the same as to advancing or regarding ignition. Most useful when using high nitro content fuels.
Can you make one with an rpm sensor?
I really wanna see you Dyno all the engines you've had especially the supercharged twin and 2rotor
What's that he is using? That rotating thingy? Sorry I'm still to this stuff
This is what I live for
Dude sorry just how did you calculate the hp .
I multiplied the force and dis
Then the turque and rpm but i didnt reach the number of 0.1 hp
Theres a worrying rattling sound 0:30 like the machine is wobbling or have bad bearings? Or is that normal?
@JohnnyQ90 Did you do the same valve thing on this engin... i know for sure, the valves dont close properly on these engines... I had to mod mine to make the valves close properly...?
Yes, same procedure here, but wrong fuel. I used 16% nitro airplane fuel, while I should have used 25% nitro for cars.
You can have the engine spin a motor to create a generator then have known load and measure the watts...
BTW where do you get those tiny boring bars?
Es es hermoso Tu arte me haces llorar cada vez que me hablas lo que estás haciendo no puedo comprender tanta maravilla No tengo más que agradecimiento Gracias por todo amor que nos obsequia y locas con ternura jamás volveré a ver al metal como una cosa muerta si no como que me grita para revivir
AYYYYY! Let's gooooo
εισαι φοβεροσ φιλε μου!
A significant portion of the engine's output may be lost to heat at the wood/metal interface.
A lot of people have suggested an electric motor as a load, I think it's a good idea too. The trick will be calibrating it.
Possible calibration procedure:
- attach a pulley to the motor
- wrap a string around it several times
- tie a known mass to the string
- drop the mass off the table
The falling mass will provide a constant known torque. (mass * pulley radius * acceleration of gravity)
If you record the drop with a camera, and have a meter stick behind the mass, you can measure the acceleration and velocity of the system. The input energy can be easily calculated using the distance the hanging mass fell.
There's a few more math steps after that, but nothing too crazy.
Wish to have lathe..
You could use a brakedisk.
I would have never thought of something like that good job man
Interesting! Works very well for a proof of concept. I think if you were looking to do an upgrade at any point, a road bike brake disk and caliper would make a more robust and sensitive system. Also, you couldn't need to get so close to the rotating assembly.
Good job my friend👍🏼👍🏼👍🏼💪🏻💪🏻💪🏻
I'm from indonesian present
There is a bit of inaccuracy due to you having to screw those in, it does offset the result a little bit. But still love the video, looking forward for more.
If you're after a mini-dyno, another interesting thing to look at would be an eddy current brake - using the lorentz force as a brake. It's substantially more tuanble than a direct mechanical brake. A spinning disc of aluminium within a strong magnetic field produces eddy currents within the aluminium, the eddy currents themselves also produce a magnetic field that opposes the rotation of the disc (which is the braking mechanism), the result is a torque transfer to the electromagnets, and heat in the aluminium.
A few ways to attack this in your application would be:
(1) to get a bunch of neodymium magnets and modulate their proximity to the disc, though the torque would need to be measured through the structure that holds the magnets as well, which complicates the construction difficulty.
(2) to get a bunch of electromagnets off eBay, and modulate the current within them with (an adjustable) constant current power supply - this may be easier to facilitate the torque measurement, but would likely cost more if you don't already have the supporting equipment. Though it is my preferred solution, as I've been designing a system like this in my own endeavours (with 50cc engines) because (if you're ok with microcontrollers/etc...) you'll be able to perform basic run-and-hold tests with an RPM feedback into a microcontroller. The microcontroller would allow the engine to run to X rpm, and then actively track and adjust the electromagnets to prevent it going any higher (thus allowing the engine to run under full load without revving out). With a bit more development after that, you'll be able to do full dyno runs and graph the results.
(3) use a brushless DC motor to generate power. By directly hooking up a motor (as a generator) and varying the electrical load on the generator. You would want to measure the torque transfer on the generator chassis and RPM, don't even worry about measuring the electrical output power to gauge input power (though it might help to confirm your findings) - using motors as generators is notoriously inefficient and the output electrical power wouldn't be an accurate number.
Try making mini disc brakes with calipers, I think it's a good idea!!
Can you please put a turbo on a mini 13b, I want to see you work that
Check if that mdf has constant friction/temperature. Seems like it could adjust more gracefully. Maybe larger diameter shaft and something else for braking material between metal/mdf torque arm?
Your measurement of the arm should have been from shaft centre to the point of contact with the scale. A pointy-er pointer would have been better to keep control of the point of contact better as well.
A pump or a eddy current brake is going to be the only thing that’s going to give you anything like a reliable result or a situation where you can hold the load long enough to read the scale. Did you read my comment on the centrifugal supercharger? A plenum could be the solution there.
Really nice machining work, you are very patient and skilled. One of my favourite channels.
When you are using horse power as a unit, could you please also show the value in watts? It would make so much more sense to me, as these engines are more comparable to small electric motors than big IC-engines.
1hp is about 750w. So 0.1hp is equivalent to a 75w electric motor
how many fuel consumption per hr
My Little Prony: Friction is Magic
This setup seems more suited for a static load like measuring the force it takes to break something.
Im guessing real dynos have rollera for a reason so you can see how the engine behaves at different rpms
How could you test electric to find out best rpm point for tire gear combination ✌️ love to see something like that 💯⚡
You may want to change your center shaft to a larger diamater. This will decrease sensitivity to clamping and increase surface area allowing for more mental volume to absorb heat a little better. The prony brakes I have used typically have a hollow cavity inside the metal part to allow for adding watter to help with cooling.
Nice to see that you made sure to talk about the limitations of your experiment!
Make sure to take into account the flex in the wood and the printed plastics too, shouldn't be too difficult for your brain to comprehend I don't think. ;)
Wouldn't it also make more sense to hook a slipper clutch up to this instead of using the wood as it's not the most "grippy" of materials? I guess that would also introduce more variables than it's worth.
I'm with Blase, when are you making an alignment machine? I bet you have something crude to deal with that aspect that works quite well!
I would suggest making a small disc brake setup to load the engine with and mount the cable or servo actuated brake on the lever arm to push on the scale. You'll be able to load the engine without directly touching the arm and affecting the measurements. Also it'll involve some cool machining and fabrication.
10/10=bravou👍😎💖✔
Your math is off.
Hp= tq x rpm / 5252
Using the force measured at 3:57 - 3oz @ 1/2 ft = 6 oz/ft or .375 lb/ft
.375 x 6600 / 5252= .471 hp.
Great work and thank you for the quality content.
Hi Johnny, may i request something please. Can we have a top 10 video of your favourate engines?
no views but 40 likes already!!! nice
absolute genius... need a RC turbo 1.9pd lmao
Nice build.
I have herd stories of professional racers using 10% nitro fuel in races when 20% is the norm. I think they said that they were competitive because they increased the engine's compression to compensate.
Edit: at 4:02 it’s hp = (torque * rpm) / 5252
Do you think the extra 5 to 10% nitro will bring you up to manufactures claims?
Suggestion:
Instead of using wing nuts and possibly adding weight to the scale with your fingers touching the wing nut. You could mount a high torque servo in some fashion to the brake and then use use a simple dial adjustment to clamp down on the brake for real precise braking and measurement. Just an idea I came up with watching it.