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Old Mar 11, 2012, 02:26 PM
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Don Stackhouse's Avatar
United States, OH, Bradford
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That's a very draggy way to run an antenna. Usualy we run them inside the tail boom, or if the tail boom is a carbon tube (like our old Spectre series), you can spiral it around the outside of the tail boom.

On our HLG's we used to cut the antenna wire short, then solder the tip to one of the wire pushrods, so that the total length was the same as the original antenna wire.
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Old Mar 11, 2012, 02:28 PM
The Lone Blue Plaid Flyer
Bob Cook's Avatar
Seattle
Joined Jan 2003
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Hi Guys,

I took a good long look at the plane. As far as I can tell it's almost done. I still need to do a final wt & bal, to set the battery position. I need to glue the tail on, and do a range check. Were getting close. Maybe another functional test of the flight surfaces. Stay tuned.

Bob in Seattle
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Old Mar 11, 2012, 02:34 PM
The Lone Blue Plaid Flyer
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Seattle
Joined Jan 2003
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Hi Don,

I agree with you that it's a lot of drag. I'm just paranoid about the antenna being to close to the C/F tail boom. I'll take the penelty and feel good about the signal getting through.

Bob in Seattle
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Old Mar 11, 2012, 03:52 PM
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Quote:
Originally Posted by Bob Cook View Post
...I'm just paranoid about the antenna being too close to the C/F tail boom...
This always worked fine for us, and our customers:
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Old Mar 11, 2012, 03:57 PM
The Lone Blue Plaid Flyer
Bob Cook's Avatar
Seattle
Joined Jan 2003
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Hi Guys,

The aft stab rod is now gluing into the brass fitting, that is in the clevis arm. See photo. The front rod has to be free to rotate as the stab moves up and down. This is a JB Weld glue, so it's going to take 8 hrs to cure. I guess that about raps it up for the day. Stay tuned.

Bob in Seattle
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Old Mar 11, 2012, 04:03 PM
The Lone Blue Plaid Flyer
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Seattle
Joined Jan 2003
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Hi Don,

WOW, I NEVER would have guessed that doing that was a safe bet on getting the signal to the plane. I heard that C/F booms eat radio signals for lunch. I am amazed that that did, in fact, work for you.

Bob in Seattle
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Old Mar 11, 2012, 06:09 PM
The Lone Blue Plaid Flyer
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Seattle
Joined Jan 2003
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Hi Guys,

Here is the forcast for the week ahead. Not looking to good. The test flights are on hold for now.

Bob in Seattle
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Old Mar 11, 2012, 07:28 PM
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Quote:
Originally Posted by Bob Cook View Post
...I heard that C/F booms eat radio signals for lunch. ...
Part of it depends on the frequency. I've heard (note, I have not tried this myself) that with our 72 MHz frequencies you can actually get away with running the antenna inside a carbon tube boom. However, with the much lower 34 MHz frequencies used in Europe, the boom blocks the signals. From what I've seen, that whole subject of antenna design is still somewhat of a "black art". However, there are some tricks, like this one, that have been proven to work acceptably well in actual practice.

Since I got my Ham license recently (for all the telemetry and FPV stuff we're using on this special project for my day job) I'm suddenly learning all sorts of new things about this subject. However, the biggest thing I've learned is how much I still don't know, but that I need to know.
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Old Mar 14, 2012, 02:05 AM
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Hi Bob,
Your Raven 3M is looking great! Looking forward to the maiden flight and had to look up KING's extended weather forecast. Fair weather in a week?
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Old Mar 14, 2012, 07:58 AM
Blueplaidcanard flyer
sdy. ny
Joined May 2007
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You are looking good Bob,the shirt should do you well.Have you found a motor for the jr falcon yet?
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Old Mar 14, 2012, 05:51 PM
The Lone Blue Plaid Flyer
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Seattle
Joined Jan 2003
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Hi Scottie,
I'm embarrased to say that I put the Falcon in the closet to keep it safe. I forgot it was in there. I have a Hacker A-20 that will work perfectly. I'll finish up the Ravin this weekend most likely. Then I'll start on it. Stay tuned.

Bob in Seattle
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Old Mar 16, 2012, 12:35 AM
Making wood fly since 2007
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USA, MN, Rochester
Joined Mar 2008
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Well you know the old adage, measure twice cut once, well I have a new one for all of you. Test the joiner tube fit with the actual wing rod, epoxy them in once. So let me tell you all what I have been up too. A while back I was making good progress on my wing, I had all the sheer webs cut and fit, I had the joiner tubes test fit, I have the upper spar glued in place. I had made these really nice plywood boxes to go around the joiner tubes and the fit nicely. So I took a piece of 1/4 inch rod, slid it into the joiner tube which was now in the wing, made sure it slid in nicely and mixed up some epoxy for the tubes and boxes. The next day I sand everything down on the top of the wing in preparation for the upper sheeting but before I do I test the joiner tubes one more time, this time with the 1/4 inch music wire.

Uh-oh problem, the music wire won't go in past the first rib without binding badly. At first I thought it was a bent rod so I tried another one and it too bound up. I went back and located the other 1/4 inch rod I originally used and it fits fine. Long story short, apparently the brass tube had a slight bend in it as it spanned across the ribs and the initial 1/4 inch rod I was using was not piano wire and it had some slop in it due to it having a slightly smaller diameter than the piano wire. Needless to say I was not going to straighten out the brass tube as it was nicely cocooned in epoxy and plywood.

After a lot of thinking I came to the conclusion that the tube needed to be straight and that would require freeing up the brass tube from its cocoon. So after many, many hours of grinding, cutting, and scrapping I have finally undone the plywood and epoxy and hopefully will be able to reset the brass tube in the forward part of the wing by this weekend. Lesson to everyone here, make sure your actual joiner rods, not just any rod, fits smoothly in the tubes prior to setting them in place with epoxy and plywood. Even a small bend in the brass tube can be a deal breaker. Live and learn.

Wayne
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Old Mar 16, 2012, 04:57 AM
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You might have been able to get a long drill bit and just ream the bore of the brass tube, without having to completely remove and replace it. Oh, well, too late now.
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Old Mar 16, 2012, 08:04 AM
Making wood fly since 2007
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USA, MN, Rochester
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I thought about that. A 1/4 inch drill bit slipped right through without issue. The next size bit up from there, 9/32, would have removed most if not all of the tube and probably mangled the root rib in the process.

Wayne
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Old Mar 16, 2012, 08:12 AM
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United States, OH, Bradford
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If that was a new, sharp 1/4" drill that slipped right through, then apparently your joiner material is larger than the nominal 1/4" size.

Still, you would have the option of taping and wrapping a piece of sandpaper around the end of a rod (just tape one end, leave the other end free so it can fling out to the tube diameter), then chucking that up in an elecric drill and sanding out the bore. Go in just the width of the sandpaper and sand that section to a perfect fit,then the next section, and so on, until the joiner fits all the way, but without excessive slop anywhere along the length.
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