| Author |
Message |
    
Roy Howard Davis
New member
Username: Royhdavis
Post Number: 18
Registered: 01-2003
| | Posted on Saturday, December 06, 2003 - 09:04 am: | |
Henri,
Thanks for the background info. Turns out that the fancy electronics board is an option. I'll start buying these motors without it and just have a two wire cable which is the basic model.
To do the motor reversing electronically requires a full H bridge, and you have to be really careful about sequencing of the switching transistors or you short the power to ground. Mechanical relays have a natural break-before-make switching function which makes the whole thing much simplier.
Tom,
The existing flap position indicator is just begging for a redesign to make it simplier and less expensive. I started looking into it when I was working on our own plane, but now that I've got all of them to look after I haven't had the time.
Right now we are working on the control system for the retractable gear, which has similar problems of knowing when to turn off the actuator. When we get that done we'll attack the flap actuator.
Roy |
Martin Vandenbroek
New member
Username: Martin
Post Number: 4
Registered: 05-2003
| | Posted on Saturday, December 06, 2003 - 10:10 am: | |
Roy,
Our RG is still ad your place. I would like to suggest a hydraulic pressure switch to cut the pump. This works both ways, up and down, of course this switch has to be intergrated with the down and locked indication. A strut switch can be used to prevent retraction on the ground.
For the flap system it would be nice to work with a cam switch mounted on the torque tube. You can use mutiple switching points on this cam for up, down and intermediate positions, one switch can do the job.
If you use a relay with a hold contact you let this switch cut the hold circuit and the motor will stop ad the next possition automaticaly after one short push on the up or down switch.
This will make life very easy!
If you donot completely understand what I mean I can sent you a diagram.
Martin from the Nehterlands.
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Reinhard Metz
New member
Username: Reinhard_metz
Post Number: 16
Registered: 03-2003
| | Posted on Saturday, December 06, 2003 - 10:41 am: | |
I have a simple position indication circuit (5 degree increments) and reversing controls with electrical braking, has been working well for over 4 years. Will post pictures, schematic, and actuator info in a couple days.
Reinhard |
Jim Oyler
New member
Username: Midniteoyl
Post Number: 64
Registered: 07-2003
| | Posted on Saturday, December 06, 2003 - 11:27 am: | |
Like Martian's idea.. What I was gonna use myself. 5 degrees at a time would be nice.
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Tom R. Hutchison
New member
Username: Tomhutch
Post Number: 143
Registered: 01-2003
| | Posted on Saturday, December 06, 2003 - 11:33 am: | |
If anyone has circuit diagrams/schematics pictures etc. Let me know and I can post them on the "technical documents" section of the web site.
Tom} |
Jerry Sjostrand
New member
Username: Jerry
Post Number: 38
Registered: 08-1999
| | Posted on Saturday, December 06, 2003 - 05:48 pm: | |
Fellow builders, I have been using my flap position indicator successfully for 8 years now. No problems. When I set the landing flaps for take off (10 degrees) I hold the ailerons full one way and look out the window and set the flaps to match. The ailerons are at 10/11 degrees full down and 17/18 degrees full up. When deploying the flaps for landing, it is not necessary to "know the position" as much as you need to feel the position. Of course, all you have to do is look out the window and see them in action if necessary. Setting at night could be more of a problem for take off but not for landing. No electrical circuit to give trouble.
For what it is worth! |
Kevin Dennes
New member
Username: Kdennes
Post Number: 73
Registered: 01-2001
| | Posted on Sunday, December 07, 2003 - 02:21 am: | |
Just my two cents (Australian) worth. Larry told me that one should not use the limit switch on the motor to control the up and down stops but to always use micro switches in line with the up and down leads of the flap motor. I have done that and everything works well but we have not had the flaps under load yet as the aircraft has not flown. Nearly there though.
Regards.
Kevin (from Downunder) |
wayne
Unregistered guest
| | Posted on Sunday, December 07, 2003 - 04:26 am: | |
I mounted 2 limit swts on the carry though behind the turq tube, 2 adel clamps around the tube trip the swts at full up/dn and cut the power as there are seperate power lines for up/dn, simple setup. As far as an indicator, MAC servos has a simple one, I didn't get around to installing mine so I look out the window too. If a few degrees one way or the other makes/breaks your TO/ldg we'll be looking for your salvage at Wentworths.Which by the way is where I just got my GNS430. |
Reinhard Metz
New member
Username: Reinhard_metz
Post Number: 18
Registered: 03-2003
| | Posted on Tuesday, December 09, 2003 - 09:12 am: | |
I've put a Powerpoint file on my website with summary pictures of my flap motor installation and control schematics, along with a zip file of a more comprehensive set of pictures.
http://www.a-and-t-labs.com/n49ex/n49ex_home_page.htm
The flap motor I have is from SKF. The pictures show the model number - I highly recommend it: It is silky smooth, good for 400 pounds of thrust, is just the right length, has internal stops and a clutch, and is industrial grade - looks like it is good for the life of the plane.
My installation is in the center, so for those with in wing installation, SKF makes shorter units. I've always been a bit suspicious of the asymetric installation - some time I can post my aerodyn. analysis which shows that at 90-120 knots the torque tubes carry 1000-2000 inch-pounds of torque!
I have a simple control with a center-off switch that sends three wires to the motor. There, a relay provides shorting for motor dynamic braking, and a pair of linearly mounted limit switches provide accurate stop points. A 9 position mechanical sensor provides signals for LED's showing 5 degree position increments. The switch provides automatic control only for full-up or full-down. Anything else requires you to look at the display. I decided any electronic control, especially with increments, was too unreliable (See Roy's comments on H-bridges - I agree).
In addition, I have a linear potentiometer that feeds a 10 segment display for the first 10 degrees. This allows you to quickly set the 10 degree take-off flaps, and innitially I included it also because there were some who thought the plane flies faster with about 2 or 3 degrees of flaps. Sometimes mine does, and sometimes not!
Here are a couple of excerpts from the pictures. Anyone need detail help on the circuits, let me know.
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