Espritmodel.com Telemetry Radio
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Old Feb 01, 2013, 04:41 PM
Team USA F3F Member
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Originally Posted by tewatson View Post
That's easy...had to do it on my Fosii. Cut a 1" x 1/8" strip of blue tape and wrap the wiper shaft at the appropriate point, to create a stop collar. Do left and right wipers at the same time to make sure they match. Glue with JB Weld as normal.

Tom
Hey Tom,

yeah! good idea. I didn't need it, but I guess if I wanted to move the servo back a bit and make the RDS rods longer, this or something similar would work good...

thanks!
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Old Feb 01, 2013, 04:42 PM
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Originally Posted by tewatson View Post
A very effective way of matching servo positions and angles is using clear templates:

http://www.rcgroups.com/forums/showp...&postcount=120

Tom

Oooooh Tom, you're just full of good ideas today!!!

I'll have to use this one next time, cause that Target guy can come up with some good ideas sometimes...

t
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Old Feb 01, 2013, 05:45 PM
LSF V aspirant
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United States, CA, Orange
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Yeah, the clear templates are the shizzle. Even a little off with the servo angle from one side to another can cause wack flap deployment. That is what's so nice about RDS...match all the install stuff up and the surfaces move evenly, both sides, on the first try.

Tom
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Old Feb 01, 2013, 05:50 PM
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Great job Tim !
A general question about the attaching the Drive rod.
any problem using a Loctite type product? (not the blue)
Or stick with the JB weld ?
Dyno
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Old Feb 01, 2013, 05:54 PM
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Originally Posted by Dyno Don View Post
Great job Tim !
A general question about the attaching the Drive rod.
any problem using a Loctite type product? (not the blue)
Or stick with the JB weld ?
Dyno
Hey Don,

I don't know about that one. It would probably be ok. You need to look up how well loctite does with metal on metal. I know JB Weld does good, so that's why I went with it. I'm sure anything that makes a tight bond with metal will do.

t
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Old Feb 01, 2013, 06:00 PM
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Loctite

Quote:
Originally Posted by tewatson View Post
Yeah, the clear templates are the shizzle. Even a little off with the servo angle from one side to another can cause wack flap deployment. That is what's so nice about RDS...match all the install stuff up and the surfaces move evenly, both sides, on the first try.

Tom
Quote:
Originally Posted by ttraver View Post
Hey Don,

I don't know about that one. It would probably be ok. You need to look up how well loctite does with metal on metal. I know JB Weld does good, so that's why I went with it. I'm sure anything that makes a tight bond with metal will do.

t
I was thinking of the Red 262 Thread locker. Should be fine..
thanks Tim,, again great job on your write up!!
Dyno
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Old Feb 01, 2013, 08:13 PM
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Way to go, Tim.
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Old Feb 01, 2013, 11:42 PM
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Way to go, Tim.
Thanks WD!

This baby is going to fly tomorrow whether she likes it or not!

t
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Old Feb 02, 2013, 11:01 AM
Build A Rocket Boys!
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One word on the clear templates for positioning the flap/aileron servos...I did this on my Fosa and found that the servo opening on my second wing was positioned ever so slightly different than the first wing. This caused binding problems when I installed the second flap servo. I ended having to shorten the flap wiper arm by 1,5mm at the coupler joint to eliminate the binding. The take away for me was to make sure I take measurements of everything first before I glued in the frames.

On another note, Tim, I noticed you said you just glued the wiper arms to the coupler. Did you mock up everything with the coupler and arm on the servo to center the wiper arm? I would think you would need to sub trim your surfaces to zero them out if this step was skipped?

Regards,

Victor
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Old Feb 02, 2013, 11:08 AM
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And BTW, nicely written build Tim. I really like following how RDS hardware is evolving. Those RDS couplers are a bit different than the ones in my Fosa. It looks like they have a spring-loaded retaining clip on the bottom to secure them to the servo shaft?
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Old Feb 03, 2013, 12:56 AM
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She Flies !!!

Took the new plane out for her maiden voyage into the skies today!

So, funny thing happened on the way to her first flight. Remember how I said that for some reason my kit didn't come with a servo tray, so I built my own?

Well, It turns out that wasn't true. It just happened to be wedged deep in the fuse and I didn't realize it! I was getting her ready to fly, and when I was putting the joiner on the fuse, I noticed the tray had come loose. At first my heart dropped and I thought that it was my tray that had come loose, so I quickly took off the nose cone, and low and behold, my servo tray was still in place. Then I realized what had happened...funny! Hmmm...ok, it wasn't going to come out easy, but it couldn't foul up anything mechanical and after thinking more about it, there really was no harm in leaving it there for now...

So, I went ahead without doing anything about it. At the expert advice of US Team member and friend/mentor Tom Kiesling, we went ahead and put it on the winch for the first flight. I had the settings the same as my other pike, and the trims seemed reasonable...what could go wrong?

So, being prepared to push forward, and triple checking all of the control surface directions, up the line she went!!! Yeee haw!!!

And oh she flew great!

Up the line with no problems! Bucket, zoom, and push over the top. Beautiful day in SoCal as you can see from the pics.

A couple of trim flights, and then we proceeded to practice speed runs. I loaded about 50% of the ballast in her cause conditions were pretty good. On her fifth flight ever, I did a 15.99 speed run! oh yeah! Followed that up with many 16's and my fastest of the day a 15.90, which happened to be the fastest time of the day by the three of us. Although I know that if Tom could have gotten a few more runs, he probably would have hit some good air and bested it...

But man this plane is great! Even with an extra servo tray floating around in the middle of it...

Tim
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Old Feb 03, 2013, 01:07 AM
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Quote:
Originally Posted by PDX Slope Pilot View Post
One word on the clear templates for positioning the flap/aileron servos...I did this on my Fosa and found that the servo opening on my second wing was positioned ever so slightly different than the first wing. This caused binding problems when I installed the second flap servo. I ended having to shorten the flap wiper arm by 1,5mm at the coupler joint to eliminate the binding. The take away for me was to make sure I take measurements of everything first before I glued in the frames.

On another note, Tim, I noticed you said you just glued the wiper arms to the coupler. Did you mock up everything with the coupler and arm on the servo to center the wiper arm? I would think you would need to sub trim your surfaces to zero them out if this step was skipped?

Regards,

Victor
Hey Victor,

Yeah, I think my pockets were actually in a little bit different of a position too. So it would be prudent to measure everything before you committed. But I think its also important to put the working servo in first and let it verify its sweet spot. But the clear templates should help you with getting the angles to match for each side.

To answer your question on the trimming, since this coupler doesn't have a particular position, you didn't have to worry about doing any of the servo zeroing with the coupler on. I just zeroed everything and left it on before I connected it while in the pocket. You have to connect it in the pocket because on this plane there is not enough room to get the full frame + servo + coupler + rod in when they are all connected. So, I put the frame in, then slide the coupler assembly (with rod) in and press the bearing in, then put the servo in and slide it on the coupler splines...

To answer your other question, I knew where the pocket was from my penciled lines, and if I laid the entire assembly over the top, I could see that there was plenty of length to make it to the center of the pocket, so I went ahead and glued the rod in.
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Old Feb 03, 2013, 01:09 AM
LSF V aspirant
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United States, CA, Orange
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Quote:
Originally Posted by PDX Slope Pilot View Post
One word on the clear templates for positioning the flap/aileron servos...I did this on my Fosa and found that the servo opening on my second wing was positioned ever so slightly different than the first wing. This caused binding problems when I installed the second flap servo.
One thing that was not necessarily made clear (no pun intended) is the templates should be referenced from the hinge line, not the hatch openings. Look closely at the pic in the post I linked earlier and you'll see the template edge positioned at the hinge...it's actually shifted a bit, but you can see that lining the edge up with the hinge line would align the position marks with the servo.

Tom
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Old Feb 03, 2013, 01:09 AM
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Quote:
Originally Posted by PDX Slope Pilot View Post
And BTW, nice written build Tim. I really like following how RDS hardware is evolving. Those RDS couplers are a bit different than the ones in my Fosa. It looks like they have a spring-loaded retaining clip on the bottom to secure them to the servo shaft?
Thanks Victor!

Yes, there is a spring loaded retaining clip on this one, and you actually need to stretch out the spring a little bit, or its impossible to get on while in the pocket...

Not sure why they did it that way, but it definitely is a solid connection once you have it in place!
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Old Feb 03, 2013, 07:13 AM
F3B and F3K
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United States, TX, Dallas
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optimized linkage should use all servo trow.

Quote:
Originally Posted by ttraver View Post
To answer your question on the trimming, since this coupler doesn't have a particular position, you didn't have to worry about doing any of the servo zeroing with the coupler on. I just zeroed everything and left it on before I connected it while in the pocket.
Tim

Like in a conventional linkage, an RDS should ideally use all the available throw of the servo to get the best mechanical advantage. Since the flaps move asymmetrically (much more down then up), you have to digitally offset the flap servos before you connect the couplers. Or in other words, if the servos are neutral on the transmitter, the flaps should already be deployed some 30 to 40 degrees. You use the subtrim to bring them back to the desired camber position in every flight mode, I use all the available subtrim there is (maximum servo offset).

This makes sure that you use all the available servo throw. It is mechanically better (higher resolution, less slop, better use of available servo torque)

If you don't do that and you still get enough flap deflection, then the RDS geometry is not ideal. You essentially throw away almost half the servo throw. It is like a conventional linkage with a too small surface horn and a too large servo horn, which does not use all servo throw.
In RDS terms, the wiper angle is too large and could be reduced for an optimal linkage

Best,
Reto
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