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Old Feb 17, 2003, 08:43 PM
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United States, NY, Spencerport
Joined Oct 2001
2,801 Posts
Micro PBF SCRAPPED

Just wanted to give everyone the bad news. Micro PBF #2 was coming along nicely, until I got to setting up the actuators.

First off, I could NOT get the actuators to center by locating the centering magnet coaxially, like everyone insisted was correct. I ended up with two huge holes in my wing, and the actuators stubbornly snapping to 45 degrees down no matter which pole of the centering magnet I pointed at the actuator!

Second, when I went to power up, one actuator was totally unresponsive! Swapped channels, still totally unresponsive. Measures as "open circuit" on my multimeter. Great. This means I have to RIP the actuator off the wing, which ruined the plane. Then I have to rip the other one off the wing as well, ruining it too. The second actuator now measures 0 Ohms (dead short).

The Micro PBF idea is DOA. I think I'll go with something a bit more conventional.
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Last edited by mkirsch1; Feb 17, 2003 at 11:12 PM.
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Old Feb 18, 2003, 12:20 AM
Foam rules
Thatovalguy's Avatar
HdG Md.
Joined Jan 2003
4,914 Posts
Now now, make some new coils and start over. Next time use rubber cement or silicone to glue them in so you can take it apart easy. Use rubber band hinge for centering. This needs some experimenting to find the right width and thickness of band. This is a setback to learn from. Other may have some better ideas for you, but this is what I use. Come on now try again, I know I wanted to see the completed plane.
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Old Feb 18, 2003, 08:27 AM
Registered User
United States, NY, Spencerport
Joined Oct 2001
2,801 Posts
Sorry to disappoint, but it's never going to happen. I can't make the actuator coils myself (no wire, no coil winder, and too ham-fisted to create anything that small and delicate), and if I can only get 1 crash out of each $19 coil, I'll go broke before the plane flies successfully.

Rubber cement and silicone will melt the foam. I originally used GWS glue, but the actuator coils flopped around too much. Flexible foam and flexible glue don't mix.

Anyway, how do you install the rubber bands? I tried repeatedly, and I can't figure out a way. Cut the slot, insert the band, put my finger on it to hold it in place, and CA my finger to the control surface... If I don't hold it, the rubber band sticks to whatever I use to apply the adhesive.
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Old Feb 18, 2003, 09:11 AM
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dhurd's Avatar
Buffalo, New York
Joined Jan 2002
1,024 Posts
Matt,
Sorry to hear about the coils. I will talk to you about it offline when we get back from the WRAM show to see what we can do for you. Meanwhile my suggestion would be to try using remote actuators for the PBF. This will allow you to move the CG further forward as well as prevent you from having to glue the actuators into the foam.

Regards,
Dan
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Old Feb 18, 2003, 09:11 AM
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RC_AV8R_181's Avatar
state college, pa
Joined Aug 2002
326 Posts
Hi,
Did you make sure to strip the enamel off the actuator leads before you soldered them to the connectors? I made this mistake a few weeks ago, I couldn't figure out what was wrong until my brother told me I had to strip the wire this can be easily done by running a match under it (very quickly) or using a knife blade to scrape off the enamel off. Then solder it like normal.

To attah rubber bands, cut tiny slots in the control surfaces and fill then with glue ( CA or white) and use tweezers to slide in the rubber bands. Just make sure the rubber bands are small enough
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Old Feb 18, 2003, 09:38 AM
Team 30 Micro EDF
Mike Taylor's Avatar
Camarillo, California
Joined Apr 2002
4,516 Posts
Rubber cement should be okay, it takes some practice. Try double-gluing it; put some on each surface, let it dry, then put a light coat on one part and put it together. This works pretty well for a non-permanent joint, but can still come loose in a crash.

Another flexible glue is RC-56. It works like latex for a flexible but very strong joint. You can peel it apart later is you need to, but it is more of a permanent solution... Plus it dries clear.
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Old Feb 18, 2003, 10:27 AM
in persuit of low wing loading
Gordon Johnson's Avatar
Boston, Mass
Joined May 2001
6,432 Posts
Matt,
Actuator based planes are tricky. There have been times late at night when I've felt like smashing the one I was working on. It takes practice.

On the rubber bands. Cut your slots so the rubber band fits in with a bit of snugness. Get a dropper with a fine tip from your LHS and use it to apply kicker. Then, put thick or medium CA on a bit of wax paper. Take a pin, tooth pick, or short length of fine piano wire and dob the CA onto the the ends of the rubber band, You want your dropper of kicker handy and you immediately put a small drop on the CA. This hardens it and keeps it from spreading. Note the technique is to have everything handy and setup so you can move fast. Then you do the same for the other end of the rubber hinge.

Scraping the wire ends is required for some magnet wire and others will do it with just heat from a soldering iron. Early on in my actuator use I didn't check the resistance before putting them in the plane. Now I do, as I hate removing them or soldering them up again.

Rubber cement should be ok for your foam, as mentioned above.

If you go the remote actuator route there are a couple of things to keep in mind. There has to be virtually no friction on the push rods. Use thin brass wire for the z-bends on the actuator end. Use very very pointed needle nose pliars to make the z-bends or the connection will shift sideways. A small amount of CA applied with a pin is all that's required to glue the z-bend to a 0.3mm CF rod. There is no need to wrap the joint. Route the push rods so they are completely free along their entire length. So, even these are tricky and take some work to master.

Keep at it.

Gordon
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Old Feb 18, 2003, 03:28 PM
Registered User
Joined Feb 2003
15 Posts
another flop

10*10 PBF
Hi Guys

My 10*10 with a mini IFO flight pack was too much for the little thing although it turned up real nice the GWS single A motor was too much for the plane as when i launched it it flew straight for like 3 metres and then went into hover torque rolling till it floped to the floor all this happened in a matter of seconds

well I guess i am gonna switch the same setup to a 16*16 PBF I am using Coro. FYI.

Lets see how this one flies.


Aziz
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