Need help with the Landtastic Project

[flyermoe 0]

Hi,

I have programmed pic for servo tester on hand. I got the servo slower working but I have no idea how. Here’s what I mean.

In step 5 it said : Just move the stick until you see the retract speed that you like best.

I didn’t noticed any change of speed when I did that.

In step 6 it said: Once the best speed is found, hold the stick steady while you remove the jumper.

How can I hold the stick in any position when I didn’t see any changes in speed??

Al

[Mr.RC-Cam 121]

It's not clear to me if your Landtastic project is actually working. I understand you see servo movement, but you mentioned that the Landtastic does not slow it down. So, something odd is going on.

What is the model number of your servo? Keep in mind that a standard "retract" servo cannot be used because they do not offer proportional movement (they can only move from one end to the other and at constant speed). So, you must use a standard servo with Landtastic.

Under the project's "Let's Test Basic Operation" section, there are four basic test steps. Please perform each step. Does each test work correctly? If not, please report exactly what you see.

In step 5 it said : Just move the stick until you see the retract speed that you like best. I didn't noticed any change of speed when I did that.

Is the servo automatically moving back and forth at step 5? It should be moving on its own without any stick movement from you. Is this what you see?

Edited February 14, 2009 by Mr.RC-Cam

[flyermoe 0]

Hi,

I figured out what was going on. My connector to the servo was working but not all the time. So I connected the servo directly to the bread board using short connecting wires. From then on the unit worked the way it was supposed to. Now I am happy!!

Now my question is the voltage rate for the chip is 5 volts. Why can’t I use a 6 volts battery in line with a 5 volts voltage regulator?

Another question is: I am planning to use a big servo to drive a ¼ scale type retractable landing gear. What torque can I use.

Thanks for all your doings,

Al

[Mr.RC-Cam 121]

Glad to hear you have it working.

Now my question is the voltage rate for the chip is 5 volts. Why can't I use a 6 volts battery in line with a 5 volts voltage regulator?

Using a 5V voltage regulator to power the Landtastic is fine.

I am planning to use a big servo to drive a ¼ scale type retractable landing gear. What torque can I use.

Landtastic does not care. So, you can install a high torque proportional servo.

[flyermoe 0]

Hi,

Now that I got the basic unit (servo slower) working. Here are my questions:

1) Is there a comparable transistor to 2N 7000 transistor that radio shack may carry? I asked because I am planning to add lost plane alert to the circuit.

2) I am planning to use a high torque servo to drive a ¼ scale (similar to ¼ scale mustang) home made retractable landing gear. Is there any ball park servo torque you can suggest?

3) Using the unit in different speed such as 2 second delay from end to end or 3 second delay from end to end and so forth changes the servo’s torque?

Thanks for all your doings and I sure love this unit.

Al

[Mr.RC-Cam 121]

1) The only thing that Radio Shack carries that might work is the IRF510, #276-2072. It is big and the gate turn-on voltage is a bit high, so it is not an ideal choice.

2) It would be best to ask other scale builders for servo recommendations for use in that size model. BTW, I understand that Airtronics and Multiplex sell a retract rated servo that is proportional (a rare combination) so you might want to look at them to see if they look good to you. These are special servos that are not the same as the standard (non-proportional) retract type.

3) Servo torque is not affected by the servo speed you use.

Thanks for the nice feedback.

[flyermoe 0]

Hi again

No……..no………..nooooooooooo I am delighted to get this servo slower unit working. I think it’s a great unit, and I will find a big enough servo to get the job done if it’s the last thing I’ll do. I can’t help myself, I am scratch builder and a tinker type of a person.

One question though. I have already installed the servo slower in a test stand and every thing is working fine. But when the wheel is in up position the servo buzzes. I am using a standard HiTec servo and driving only one retract to just see how this unit works. I am not sure about the retract's brand. I’ve installed a servo saver and also I played around w/ end point adjustment with out any luck to stop the buzzing sound. As soon as I push the landing gear’s leg (ole) up the buzzing stops. Although these retract and servo are NOT what I am planning to use but once again I am trying to get myself familiar with the servo slower unit. The retract speed is about 4 seconds from end to end.

Thanks,

Al

[W3FJW-Ron 0]

It sounds like the servo does not have quite enough torque to pull the gear all the way up. That 90 degree angle is where the servo has to work the hardest. Giving it that final little lift with your finger would seem to verify this.

Edited February 17, 2009 by W3FJW-Ron

[Mr.RC-Cam 121]

If you are sure the servo is not stalled then try some others to find one that suits your needs.

[flyermoe 0]

Hi,

Your advice was right on the money. I replaced the standard HiTec servo with a spektrum DS821 servos with 72 oz/in of torque. The buzzing stopped and the gear went up and in lock position with out any trouble or buzzing sound at all.

Once again, thanks for all your doings and advices.

Al