Quote from: CircuitFlyer on August 06, 2025, 01:21:47 PM
The twin timer currently under development is intended for full fuse models and has connections for motor 1 ESC, motor 2 ESC, landing gear servo, motor 1 RPM, motor 2 RPM and a remote pushbutton start switch. Each motor is controlled independently not in parallel. The circuit board will have a JST-SH socket for plugging in a remote Neopixel LED as well as a pin for a remote touch sensor using conductive tape. I recently revised the PCB design to make it a little more compact and to fix an error I made on the original prototype board. Maybe by early Fall I will have the latest design ready for test flights.

The accelerometer is mounted on the timer PCB. The timer can be mounted in any orientation as long as the edges of the timer align with the axis of the airplane.

Thanks - My breath is baited! 

Ken

Will this work with the Bad Ass 60 amp Rebel V2 Series ESC? Thank You

Yes, the BadAss Rebel Series work very well.  Be sure to set the BEC voltage to 5v.  I use Rebel V2 40A on my test rig.  I don't suggest the 20A and 30A "Lite" series as the BEC voltage is fixed at 6V.

Thank You Paul. Look forward to getting the system up and running.

How is the twin coming along?

Ken

I have completed a few flight sessions with the prototype unit. I still have some more code improvements I want to work on. Beta testers are in the loop and hopefully we can get it all sorted out over the next little while.

Claude AI has really helped improve my coding skills.  No, he won't be helping you fly the perfect pattern anytime soon.

Hi all,

may I kindly ask for a step back from twin dreams to the basic C&D single engine timer?

Recently, I bought two of them. No flight experience yet. First C&D equipped model is finished, awaiting flyable weather for its maiden.

Up to now I have no practical experience with all the fancy features. But at least, I went through a number of workshop discussions. My clubmate raised an issue which I'd like to forward here in hope for comments:

The overload safety stop feature is generally appreciated when it comes to prop ground contact. Cutoff is what we want. And cutoff is what the C&D timer delivers.

However, in-flight rpm-drop due to voltage drop is different. The C&D timer treats this like ground contact, and cuts off the motor. Immediately. Without any warning. This makes me thinking.

Let's say you have found a motor/propeller/battery setup which works well under "normal" conditions. Now let's consider the non-ideal case of cold weather with cold battery. Battery voltage is lower than usual. You initiate a sharp upward turn from level to vertical, and the C&D timer wants to give some extra sharp corner boost. But the remaining voltage isn't sufficient for building up the extra rpm.

I've tried this during a workbench test, and the result is: Cutoff! 

I have to admit, that up to now I have no in-flight experience. But thinking of a plane with its nose pointing upward and a dead motor right after a sharp upward corner sounds to me like the same plane is digging a hole in the ground two seconds later. Or am I mistaken?

Wouldn't it be wise to treat "low rpm" different from "no rpm = blocked"? Wouldn't it be better to have some warning instead? Something like the regular stopping procedure with flashing LED to give you time for landing preparation?

Stefan

Stefan,

The cutoff is programmed to happen when the RPM drops below 75% of the current desired 'setpoint' RPM.  That's a lot.  You would need a substantial drop in voltage to allow the RPM to decrease to that point.  In the mean time, you would likely notice a considerable drop in speed and performance that would convince you to avoid attempting a wingover.  The corner boost function is limited to a maximum of 400 RPM increase.

In other words, you may have devised a method to test certain conditions on the workbench that might not translate to actual inflight testing in the same manner.  I have not received any feed back that the current cutoff logic is an issue.  ESC's also have their own built-in low voltage cutoff protection.

The reason for the timer prop strike cutoff is to prevent damaged ESC's or motor windings due to overcurrent.  If something is causing the RPM to drop 25% your current is going through the roof.  I'd prefer to not wait until the RPM is 0.  There is also the case of an accident that breaks the prop but does not fully stop the motor.  There are an endless number of 'what if's' to consider and it is a challenge to attempt cover everything.

Paul

Paul,

thank you for your explanations. During my workbench trials I did not notice the 25% RPM drop. But this doesn't mean anything, since I wasn't focused on this effect.

Your explanations sound quite convincing to me. The 75% margin concept is absolutely plausible.

I am tempted to add, that for a flight condition in the 100% - 75% RPM regime some sort of a visible "low rpm" or "low battery" warning (flashlight?) would be helpful. But I don't want to overstress this point. For now I'm fine, and am eager to go out for first in-flight experiences.

Thanks a lot for clarification.

Stefan

Hello. I couldn't find anywhere to ask so I'm asking here. I have bought a timer of the tindie shop, updated it to 1.5 but i can't get it to connect to the bluetooth app and also the touch pin doesn't do anything either. I have hocked everything to it, it initializes the ESC but it doesn't do anything besides that. Does anyone have any idea i can try? thx

Quote from: ALEX_BZ on June 10, 2026, 12:49:37 PMHello. I couldn't find anywhere to ask so I'm asking here. I have bought a timer of the tindie shop, updated it to 1.5 but i can't get it to connect to the bluetooth app and also the touch pin doesn't do anything either. I have hocked everything to it, it initializes the ESC but it doesn't do anything besides that. Does anyone have any idea i can try? thx

How are you trying to put it in programming mode?

Will it start when you do the startup process?

Please advise

If all else fails you can email Paul. He is pretty responsive

Quote from: Paul Taylor on June 10, 2026, 03:17:54 PMHow are you trying to put it in programming mode?

Will it start when you do the startup process?

Please advise

If all else fails you can email Paul. He is pretty responsive

As per the instructions, 5 taps on the pin should put it in programming mode. Shouldn't it? Ideally i would like to connect to it with Bluetooth. 

This may seem rudimentary, but if your skin is very dry, the pin may not sense the taps. Moisten your finger and try again.

https://circuitflyer.com/Climb_and_Dive/docs/Installation.html

You will need the bluefruit phone app up and running as well. 
The light on the timer will turn blue when it's all linked up.

https://circuitflyer.com/Climb_and_Dive/docs/Programming/Bluetooth%20Programming.html

That't the issue. The app doesn't see it. tried multiple apps it's just not showing up. The LED is green and stays like that after initialization.

Quote from: ALEX_BZ on June 12, 2026, 06:16:44 AMThat't the issue. The app doesn't see it. tried multiple apps it's just not showing up. The LED is green and stays like that after initialization.

Rudimentary diagnostic step: Is Bluetooth enabled on your phone?

Alex, check you Stunt Hanger private message inbox.  Let's see if we can do some more troubleshooting to get it working.

Does the latest version of the C&D timer include the three pull cut-off?

Best,   DennisT

Yes