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Old 09-15-2019, 05:10 PM
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Join Date: Oct 2003
Location: Saint George , SC
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Dave sent me his latest version of the drag chute Lua program and I installed the files in my DS-24. I activated the Lua program and set up the functions for chute door, chute deploy, and chute jettison that the program creates. Then I assigned channels in servo setup and plugged in 3 servos for door, deploy, and jettison.

Here are the screens that the chute current Lua program sets up.

The main screen allows selection of switches, RPM sensor, time delay for deployment after door open.

There is a selectable high speed and low speed and option to have chute at mid flap setting, ie half flaps. The idea for the speed is that after touch down the wheels have to see at least the high speed first and then see the lower speed to allow the chute to deploy. I set these at first to 25 and 20 mph for bench testing.

There is another program screen where you specify all the switches for the consent conditions but I did not take photos of it. That is the screen where you tell it what the diameter of the wheel is to determine speed from RPM.

If you select the load test option at the top of the first page you get the load test page. This photo shows Load selected which opens the door and jettison hook so you can load the chute.

This photo shows the test function that allows ground or bench testing by opening the door and deployment spring or air cylinder with out having to have all the normal conditions met

This is the status page that shows current status of all the chute deployment consent conditions. This is how it would look during normal flight after gear and flaps are retracted.

Beginning a landing approach flaps are extended

Gear is extended

Throttle is reduced to idle

Deploy switch is activated

Brakes can be applied before or after touchdown. The wheel speed sensor would have to see the high limit followed by the low limit and then all the deploy consent conditions are met. At this time the top two blue bars move right showing servo activation of the door and deploy system...and out pops the chute!

After landing the jettison switch is activated and releases the chute. Note the blue jettison bar did not move. This is because the jettison switch is a consent switch and the actual jettison occurs when flaps are raised with the jettison consent switch on. I completely forgot about how it is programmed to work when I took this photo.

Here is the Jeti RPM telemetry window and the Autochute Sensor which calculated ground speed.

Here is my first bench test. 3 servos, Jeti receiver, battery and sensor on gear. Gear is clamped to table and cordless drill with a Carbon Z Cub wheel attached with a bolt.

Here is the concept of test. Turn the wheel with the drill, activate the switches and watch the servos activate the chute. I could only get up to 28 mph with the battery drill

Got the "Binford 5000" more is better drill and got better speeds

2200+ RPM and 40+ mph. I found out the wheel is way out of balance. I nor Dave have ever checked wheel balance before but is pretty bad. Any suggestions on how to balance a jet wheel would be welcome.

I found the Lua program is currently not using the speeds for deploy because I get deployment when all other conditions are met no matter that the speed is doing. Dave is working on debugging that. I'm sure it will get fixed and this will be the coolest drag chute system available.

Again, I am completely unable to do this Lua stuff without being lead by the hand and many thanks to Dave for doing just that. He thought up all these cool ideas, programmed the Lua program, designed the mounting system for the sensor and magnets, and taught me how to say "Lua". WIthout his assistance I would have glued the door shut and never considered trying it.

Many thanks Dave!

Last edited by Viper1GJ; 09-15-2019 at 05:44 PM.
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