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JP hobby elec brake question

Old 05-16-2022, 01:05 PM
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Vincent
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Default JP hobby elec brake question

Im trying to get more breaking pressure on my JP F16 gear. They wont engage if the landing speed is on the fast side. Would it help if i set the travel up to 150% ?? Right now its 100. Thx
Old 05-16-2022, 01:37 PM
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You can try, some radios treat "100" differently than others
Old 05-16-2022, 04:36 PM
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I've been trying to get better braking from the JP brakes on my F-16XL. At first I was using only 2S LiPo batteries for brakes and had almost no braking power on pavement. I went to 3S LiPo using an ASSAN AG63 and it was much better but the brake output from the controller failed. Now I am using the JP brake controller on 3S LiPo and it is OK but not as good as the AG63 on 3S. I'm using 100% travel on the Jeti for brake control. Good luck. Let us know if you find a working combo.
Gary
Old 05-16-2022, 05:43 PM
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Originally Posted by Viper1GJ View Post
I've been trying to get better braking from the JP brakes on my F-16XL. At first I was using only 2S LiPo batteries for brakes and had almost no braking power on pavement. I went to 3S LiPo using an ASSAN AG63 and it was much better but the brake output from the controller failed. Now I am using the JP brake controller on 3S LiPo and it is OK but not as good as the AG63 on 3S. I'm using 100% travel on the Jeti for brake control. Good luck. Let us know if you find a working combo.
Gary
I did not think the JP brake controller can handle 3s. Is the brake force pretty even?
Thanks,
Tone
Old 05-16-2022, 06:31 PM
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The simple separate JP Brake controller is rated for 2-6S, I run 3S on the brakes installed on my Flex Jet Pro and they work great and are even if you use and on/off scenario, don't even try to make them work proportionally. Limit brake power with end point
Old 05-17-2022, 04:55 AM
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Im using the simple JP brake controller running off of a 3 cell life.
Old 05-17-2022, 11:49 AM
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I only have luck keeping the models going straight with AG63 controllers and 2S LiIon from RX...

proportional works ok with mix in TX from elevator,
so when I land I push elevator forward and it slowly engages...

Stock JP controller and even small Xicoy with pulse effects caused model to abruptly roll to one side and hit ground with a wingtip...


Same as this guy:

https://youtu.be/CGVMrroOHMc

Last edited by dr.tom; 05-17-2022 at 11:51 AM.
Old 05-18-2022, 08:05 AM
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Originally Posted by Vincent View Post
Im trying to get more breaking pressure on my JP F16 gear. They wont engage if the landing speed is on the fast side. Would it help if i set the travel up to 150% ?? Right now its 100. Thx
I am having the same issue with my Baja 2.6 meter L-39
Thread here: BajaHobby L39

I get good braking force at stand still and up to around 15 mph, but zero (and i mean zero) braking force above that.
I seems JP have several different brake designs on their wheels. The smaller wheels has the common design with a brake disc between the "drum" and the wheel, wile the bigger wheels (i have 95mm JP wheels and brakes) have a design with 4 metal plates held by magnets to the inside of the wheel.

The faster the wheel is turning, the stronger the sentrifugal forces are and i have a feeling that at landing speeds, lets say 50 mph the sentrifugal forces are too great for the magnet to overcome and that why you get no braking force when u really need it at high speeds.

I did some calculations. @ 50 mph, my 95mm wheels will have around 800 G at the outer edge of the tire. The brake pads sit about 2 cm further towards the axle, so lets say they get about 500 Gs of sentrifugal force that the electro magnet would have to overcome before start have a braking effect. I feel the problem lies in the design of these brakes more then in the controller.

I been emailing JP europe, asking if any changes to the brake design and informing them i just want to buy brakes (or wheels and brakes) that actually works, but I have gotten very vague answers to direct questions about what is different and even if the design is the same or not. Makes it kind of hard to decide if order new brakes/ wheels or not when not get a clear answer if they are the same poor design or not.

So my question is if anyone gotten the JP braked with the 4 metal plates to work well at high (landing) speeds, and if so how?

JP smaller wheels brake design. A more common and well working design IMO

JP bigger wheels brakes design. The 4 metal plates experience huge sentrifugal force as they are attached to the inner side of the rim on the rotating wheel. Did anyone get these brakes to work well at high speeds?

JP big wheel brake drum. Notice the small surface area to create friction for metal plates in the wheel

4 metal plates are held in place with 4 small magnets in the rim

brake plates removed. These plates would have to overcome a sentrifugal force of around 500 G @ 50 mph before even touching the brake drum.

Sentrifugal loads on the wheel at a given speed. The brake plates sit about 2 cm in towards the axle, so lets say 500G


Old 05-18-2022, 09:23 AM
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Originally Posted by SAP_2000 View Post
I am having the same issue with my Baja 2.6 meter L-39
Thread here: BajaHobby L39

I get good braking force at stand still and up to around 15 mph, but zero (and i mean zero) braking force above that.
I seems JP have several different brake designs on their wheels. The smaller wheels has the common design with a brake disc between the "drum" and the wheel, wile the bigger wheels (i have 95mm JP wheels and brakes) have a design with 4 metal plates held by magnets to the inside of the wheel.

The faster the wheel is turning, the stronger the sentrifugal forces are and i have a feeling that at landing speeds, lets say 50 mph the sentrifugal forces are too great for the magnet to overcome and that why you get no braking force when u really need it at high speeds.

I did some calculations. @ 50 mph, my 95mm wheels will have around 800 G at the outer edge of the tire. The brake pads sit about 2 cm further towards the axle, so lets say they get about 500 Gs of sentrifugal force that the electro magnet would have to overcome before start have a braking effect. I feel the problem lies in the design of these brakes more then in the controller.

I been emailing JP europe, asking if any changes to the brake design and informing them i just want to buy brakes (or wheels and brakes) that actually works, but I have gotten very vague answers to direct questions about what is different and even if the design is the same or not. Makes it kind of hard to decide if order new brakes/ wheels or not when not get a clear answer if they are the same poor design or not.

So my question is if anyone gotten the JP braked with the 4 metal plates to work well at high (landing) speeds, and if so how?

JP smaller wheels brake design. A more common and well working design IMO

JP bigger wheels brakes design. The 4 metal plates experience huge sentrifugal force as they are attached to the inner side of the rim on the rotating wheel. Did anyone get these brakes to work well at high speeds?

JP big wheel brake drum. Notice the small surface area to create friction for metal plates in the wheel

4 metal plates are held in place with 4 small magnets in the rim

brake plates removed. These plates would have to overcome a sentrifugal force of around 500 G @ 50 mph before even touching the brake drum.

Sentrifugal loads on the wheel at a given speed. The brake plates sit about 2 cm in towards the axle, so lets say 500G
If the JP brake controller will work on 3s why not give that a try?
Tone
Old 05-18-2022, 03:27 PM
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Here is the JP controller I'm using. It says 7.4-25.2v on the front cover. I'm using 3s LiPo for the brakes. So far only used on grass. Will get to check it on pavement next week.
Gary
Old 05-19-2022, 12:26 AM
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Originally Posted by Viper1GJ View Post

Here is the JP controller I'm using. It says 7.4-25.2v on the front cover. I'm using 3s LiPo for the brakes. So far only used on grass. Will get to check it on pavement next week.
Gary
My L-39 was flown off grass by the previous owner and he never mentioned anything about brake issues.

Please let me know here or in the other thread how it works out.
I have the same controller but running on 2s. Happy to go with 3 or even 4s if that solves the problem.

Also, still interested to hear if anyone has had success with the 4-plate brakes at high speeds on asphalt. So far no one has confirmed that.
Old 05-19-2022, 04:46 AM
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Originally Posted by SAP_2000 View Post
I am having the same issue with my Baja 2.6 meter L-39
Thread here: BajaHobby L39

I get good braking force at stand still and up to around 15 mph, but zero (and i mean zero) braking force above that.
I seems JP have several different brake designs on their wheels. The smaller wheels has the common design with a brake disc between the "drum" and the wheel, wile the bigger wheels (i have 95mm JP wheels and brakes) have a design with 4 metal plates held by magnets to the inside of the wheel.

The faster the wheel is turning, the stronger the sentrifugal forces are and i have a feeling that at landing speeds, lets say 50 mph the sentrifugal forces are too great for the magnet to overcome and that why you get no braking force when u really need it at high speeds.

I did some calculations. @ 50 mph, my 95mm wheels will have around 800 G at the outer edge of the tire. The brake pads sit about 2 cm further towards the axle, so lets say they get about 500 Gs of sentrifugal force that the electro magnet would have to overcome before start have a braking effect. I feel the problem lies in the design of these brakes more then in the controller.

I been emailing JP europe, asking if any changes to the brake design and informing them i just want to buy brakes (or wheels and brakes) that actually works, but I have gotten very vague answers to direct questions about what is different and even if the design is the same or not. Makes it kind of hard to decide if order new brakes/ wheels or not when not get a clear answer if they are the same poor design or not.

So my question is if anyone gotten the JP braked with the 4 metal plates to work well at high (landing) speeds, and if so how?

JP smaller wheels brake design. A more common and well working design IMO

JP bigger wheels brakes design. The 4 metal plates experience huge sentrifugal force as they are attached to the inner side of the rim on the rotating wheel. Did anyone get these brakes to work well at high speeds?

JP big wheel brake drum. Notice the small surface area to create friction for metal plates in the wheel

4 metal plates are held in place with 4 small magnets in the rim

brake plates removed. These plates would have to overcome a sentrifugal force of around 500 G @ 50 mph before even touching the brake drum.

Sentrifugal loads on the wheel at a given speed. The brake plates sit about 2 cm in towards the axle, so lets say 500G

based off your pictures of the bigwheel brakes, the lack of breaking is because of the lack of surface area between the wheel pads and the brake drum.

if you were to fill in the area on the brake drums between the metal areas with an epoxy so as the entire drum surface is flat, i bet the breaking action would improve greatly. If you could find some sort of thin break liner (maybe some DIY gasket maker material or flat O-ring) you could probly make them work amazingly well.
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Old 05-19-2022, 05:38 AM
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Originally Posted by invertmast View Post
based off your pictures of the bigwheel brakes, the lack of breaking is because of the lack of surface area between the wheel pads and the brake drum.

if you were to fill in the area on the brake drums between the metal areas with an epoxy so as the entire drum surface is flat, i bet the breaking action would improve greatly. If you could find some sort of thin break liner (maybe some DIY gasket maker material or flat O-ring) you could probly make them work amazingly well.
That's a pretty good idea to increase the surface area at the magnet side. I have the some L39 jet and use a Xicoy Lg 15 controller for the brakes and retracts. I have not issues with mine. However, I only fly off of grass.
Thanks
Tone
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Old 05-19-2022, 07:38 AM
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Originally Posted by SAP_2000 View Post
I am having the same issue with my Baja 2.6 meter L-39
Thread here: BajaHobby L39

I get good braking force at stand still and up to around 15 mph, but zero (and i mean zero) braking force above that.
I seems JP have several different brake designs on their wheels. The smaller wheels has the common design with a brake disc between the "drum" and the wheel, wile the bigger wheels (i have 95mm JP wheels and brakes) have a design with 4 metal plates held by magnets to the inside of the wheel.

The faster the wheel is turning, the stronger the sentrifugal forces are and i have a feeling that at landing speeds, lets say 50 mph the sentrifugal forces are too great for the magnet to overcome and that why you get no braking force when u really need it at high speeds.

I did some calculations. @ 50 mph, my 95mm wheels will have around 800 G at the outer edge of the tire. The brake pads sit about 2 cm further towards the axle, so lets say they get about 500 Gs of sentrifugal force that the electro magnet would have to overcome before start have a braking effect. I feel the problem lies in the design of these brakes more then in the controller.

I been emailing JP europe, asking if any changes to the brake design and informing them i just want to buy brakes (or wheels and brakes) that actually works, but I have gotten very vague answers to direct questions about what is different and even if the design is the same or not. Makes it kind of hard to decide if order new brakes/ wheels or not when not get a clear answer if they are the same poor design or not.

So my question is if anyone gotten the JP braked with the 4 metal plates to work well at high (landing) speeds, and if so how?

JP smaller wheels brake design. A more common and well working design IMO

JP bigger wheels brakes design. The 4 metal plates experience huge sentrifugal force as they are attached to the inner side of the rim on the rotating wheel. Did anyone get these brakes to work well at high speeds?

JP big wheel brake drum. Notice the small surface area to create friction for metal plates in the wheel

4 metal plates are held in place with 4 small magnets in the rim

brake plates removed. These plates would have to overcome a sentrifugal force of around 500 G @ 50 mph before even touching the brake drum.

Sentrifugal loads on the wheel at a given speed. The brake plates sit about 2 cm in towards the axle, so lets say 500G
Yup...you describe my problem exactly and i have those same wheels and brakes. Im going to retro the mains with a set of SM F-16 air wheels and brakes. Im not convinced the problem can be resolved by jp.
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Old 05-28-2022, 12:03 PM
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I have these on my T-7A XXL.

They lock up easily and dont do much braking at higher speed. has anyone found a solution to this or is swapping in a different manufacturers brakes only viable option left?
Old 05-28-2022, 06:17 PM
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Frustrated by JP brakes again.
I got one flight on my F-16XL with JP brakes and controller today at FIF. Brakes were checked 5 times before flight. Twice in pits before starting and 3 times during taxi out and before take off. Brakes worked great. Jet flew great and landed very softly. Brakes were applied and there was nothing. Tried several times and nothing. Jet roll almost out of sight on runway and I shut off the turbine. After a few minutes I rode crash cart out to get the jet. Found it sitting still on all three gears so I switched off the jet. Rode crash cart back to the start area and put jet on ground. Both brakes were locked. Switched jet back on and cycled brakes then switched jet off. No change. Carried it back to pit tent and put it on ground. A few minutes later I removed cockpit tray and smelled smoke. JP brake controller shown in post # 10 was still powered, red light on, and was too hot to touch. I removed the battery connection to controller and the brakes unlocked. After cool down if battery was connected even with RC power switched off the brake controller red light would come on and the brakes would lock. The controller seems to be fried.
I don't know why the brakes worked every time at taxi speeds but did nothing at all at landing speeds. Also I have no idea why controller powers brakes when battery is connected. I fly mostly on grass and have not had no brakes like on pavement.
Very frustrated now with JP brakes. My jet weighs about 39-45 lbs depending on fuel.
Any suggestions appreciated.
Gary

Last edited by Viper1GJ; 05-28-2022 at 06:19 PM.
Old 05-28-2022, 09:33 PM
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If I had to venture a guess I would say they worked on the ground initially because it was a short time period. After a 7 minute flight or so the controller most likely over heated and failed. That's why you had problems after the flight. This is in no way and excuse. I have never been a fan of the JP brake ontrollers and very often switch to the xicoy lg15. I recently tried the AG68 anti slip controller and it seems legit but have only used it during a taxi test. Not an actual flight at this time.
Tone

Last edited by Agrav8ed; 05-29-2022 at 05:30 PM.
Old 05-29-2022, 04:08 AM
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Vincent
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I replaced my JP elec wheels and brakes with a pair of SM F16 1/6th air type. They work great no more bs not stopping.
Old 05-29-2022, 04:20 AM
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Well, you had plenty of roll out room Gary! I can picture losing site of the jet while it's still perfectly on the runway up there, sorry I couldn't make it this year.
Old 05-29-2022, 04:58 AM
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Would using 4-6s battery makenany difference : more power in the coils= magnets working..? Design is nice but thoroughly thought..
Old 05-29-2022, 02:48 PM
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A little out of left field but the RC cars guys have great hydraulic disk systems.



Your model's need to be a certain scale yet food for thought.

Regards,
Old 05-29-2022, 03:59 PM
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I started out with the Xicoy LGC-15 on 2S. Since the JP retracts can only use 2S the brake power is also limited to 2S from the LGC-15. I switched to the AG-63 to allow brakes to use 3S power. For a while it worked excellent. Perfect straight steering and braking. But then the brake outputs on the AG-63 stopped working. The steering still worked. So I went back to the JP brake controller that is now toast. I've been told that the heavier jets need 3S to get the stopping power from the JP brakes. That is why I switched away from the LGC-15.

Vincent, did the SM air brakes fit on the JP gear with out a lot of fuss or machining? Where did you get the SM 1/6 F-16 brakes?
Gary
Old 05-29-2022, 11:50 PM
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I can route power for jp controller from 3s Lipo engine battery easily. Might be worth a shot. If only also retract vontroller would take 3s too. With 2s its pretty slow to retract.
Old 05-30-2022, 06:07 AM
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Originally Posted by Ceeray View Post
I can route power for jp controller from 3s Lipo engine battery easily. Might be worth a shot. If only also retract vontroller would take 3s too. With 2s its pretty slow to retract.
I am not sure the retract motors can take 3s. You can message Shane Young from JP on Facebook. He can let you know for sure. It may be worth using a separate brake controller just for the retracts.
Tone
Old 05-30-2022, 04:45 PM
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I understand JP retract motors are limited to 2S voltage or they will smoke. My jet has a Jeti CB400 installed powered by 2 x 3S LiPo batteries. The output is regulated to 8v for the servos and JP gear controller. The brake power is 3S LiPo direct to the brake controller. This is how I powered the AG63 before the brake output failed and the JP brake controller before it fried. The best performance by far was with the AG-63 but the brake side failed. I have another one available so I may install it and see how it goes from there.

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