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Old Jan 10, 2006, 12:48 AM
Tied to the whipping post
DangerBird's Avatar
Warm-Sunny-no-Wind, Az.
Joined Dec 2003
2,480 Posts
I think its pretty funny how Joe's post of his cool backyard workshop has evolved into a discussion of detect, evade, defend....

Nice workshop Joe.
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Old Jan 10, 2006, 02:40 AM
American MoonMan
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United States, CA, San Diego
Joined Jul 2003
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Or maybe devolved..................

Joe
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Old Jan 10, 2006, 05:16 AM
JettPilot's Avatar
Miami
Joined Apr 2005
11,084 Posts
A bit of twist in the tail does not bother anything, it will still fly nicely. I would suggest a test flight before you go to the work and add weight trying to tail not to twist.

The amount of twist in this airplanes tail is pretty suprising and has alarmed some poeple, but its strong and the airplane flys rock solid...
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Old Jan 10, 2006, 11:34 AM
I AP'd myself again......
aviatordave's Avatar
Yawn....Iowa
Joined Mar 2005
2,500 Posts
ya, there is some serious twist there......how do you adjust to make it straight?
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Old Jan 10, 2006, 11:42 AM
JettPilot's Avatar
Miami
Joined Apr 2005
11,084 Posts
Hahahaha, after I posted that while half asleep this morning, I realized that was probably the wrong picture to use when talking about tail twist

But in all seriousness, I was talkign about the plane. The tail boom is made out of Carbon Fiber tubes, and the tail iteslf out of EPP, so it has a lot of give to it, and I was wondering if it would flutter, etc. But its rock solid and the plane flys better than I had hoped for
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Old Jan 10, 2006, 12:56 PM
Aerial Shutterbug
RMihara's Avatar
San Mateo, California, United States
Joined Nov 2001
5,007 Posts
Quote:
Originally Posted by Dark Overlord
...I think I will also have a chance to install my tiltable camera mount. It is going to be directly shaft driven from an HS-81mg...
Hey Joe, as I am working on a tilt mount for my heli set-up I thought about adding a servo delay driver. From several videos that I've seen, pan/tilt functions appear to have a small amount of 'twitch' in them. Not sure if this is caused by ratcheting of a TX stick/knob/slider or simply because of the high speed nature of a servo...maybe a combination of all of the above. I figure a delay driver would help to smoothen out the servo's response by slowing down it's effective speed and, apparently, these drivers also provide some added 'boost' to an analog servo's torque. Would help to keep a pan/tilt mount from wigglin...

Quote:
...I do have one concern though. The carbon fiber tube does seem to allow the tailfeathers to twist a little more than I like. I may have to come up with some sort of an anti-twist preventor to counter that which is showing up now under power...
Would you happen to know what the 'lay-up' of that CF tube is? Torsional rigidity of a composite tube is highly driven by a 45 fiber orientation, relative to the longitudinal axis of the tube itself. If your tube happens to be an arrow shaft (just an assumption here), most of those shaft types have fibers orientated along the length of the shaft. Adds bending stiffness but lessens torsional stability. A simple spiral wrap of kevlar thread (otherwise known as a 'diamond braid' because of the visual appearance) bonded with epoxy could help.

-Roger
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Old Jan 10, 2006, 08:08 PM
American MoonMan
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United States, CA, San Diego
Joined Jul 2003
2,722 Posts
Quote:
Originally Posted by RMihara

Would you happen to know what the 'lay-up' of that CF tube is? Torsional rigidity of a composite tube is highly driven by a 45 fiber orientation, relative to the longitudinal axis of the tube itself. If your tube happens to be an arrow shaft (just an assumption here), most of those shaft types have fibers orientated along the length of the shaft. Adds bending stiffness but lessens torsional stability. A simple spiral wrap of kevlar thread (otherwise known as a 'diamond braid' because of the visual appearance) bonded with epoxy could help.

-Roger
Roger,

You are most likely correct regarding the orientation of the fibers in the carbon tube I am using. It is not an arrow shaft but very similar. While it does appear to be very stiff along its length, once installed as a fuselage boom, it does most definitely suffer from torsional twisting. I do think that it will be okay once the aircraft is under flight loading though. I will just have to moniter it carefully once the aircraft is ready for test flights. I may even try out something a friend and I had discussed several years ago about helping to strengthen the stock Slow Stick fuselage. We had thought about using expanding foam to fill it up. That may work well here too, but instead of using foam, I think that once I put my control system into the boom, I will liberally fill it with Gorilla Glue. It expands by about 7 times its own volume, and becomes pretty rigid at the same time. I think that it may work to stiffen the boom and retain my control tubing rather nicely, all while adding only a small amount of weight to the aircraft. Will see how it works out....................

Joe
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Old Jan 10, 2006, 09:30 PM
Aerial Shutterbug
RMihara's Avatar
San Mateo, California, United States
Joined Nov 2001
5,007 Posts
Hi Joe,

IIRC, foam 'coring' only works (appreciably) if it is a very dense or hard material, most likely not worth the added weight especially in the tail of the aircraft. Foam generally has poor shear stiffness--which is what it will be subjected to with torsional loads, 0.02 Gorilla glue on the other hand...

I know this sounds odd but you could also 'skin' the CF tube with plain paper (rolled into a tube). That will certainly add a tremendous amount of torsional stability. If you can find a way to add the paper liner to the ID of the CF tube, no one will see it (or know) .

BTW, the porch light on your workshop is a nice touch!
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Old Jan 11, 2006, 02:48 PM
American MoonMan
Joe Bennett's Avatar
United States, CA, San Diego
Joined Jul 2003
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Roger,

What are your thoughts on the idea about filling and allowing to expand with Gorilla Glue? Might add maybe 10-15 grams total once expanded. Doing anything to the CF tube at this point that would entale the outside is out of the question. It is installed, and partly inaccessable (the part inside the tailcone). Tailfeathers are already glued to rear also.

The porch light is there for more than looks. Economical too, only using a 13 watt flourescent bulb in it. The backyard gets pretty dark and the light allows me to traverse the minefield (beagle leavings that is ) betwix hazardous waste removal periods. I know it is impossible, but I still suspect that my to beagles leave at LEAST twice the amount they are fed each day. Later.....

Joe
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Old Jan 12, 2006, 02:39 AM
Aerial Shutterbug
RMihara's Avatar
San Mateo, California, United States
Joined Nov 2001
5,007 Posts
Hi Joe,

Of all the adhesives I've used, Gorilla Glue is not one of them

But, one way to know if that glue yields torsional benefits in your application would be to twist a specimen slug of cured adhesive with the same OD as the CF tube's ID. If it feels like it is torsionally stiffer than the CF tube then it should work.

-Roger

Btw, I ROFLOL at your minefield comment. Perhaps an A.P. reconnaissance mission of the minefield prior to walking it is in order.
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Old Jan 13, 2006, 11:09 AM
American MoonMan
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United States, CA, San Diego
Joined Jul 2003
2,722 Posts
Group,

Should have time later to work on the BE. I still have the flap and the tilt servos to mount. I have decided after careful thought to make my still camera mount lighter and more open to allow for ease of removal and mounting of the camera. Also, since the S6 IR port is located differently, will have to allow for mounting of the PRISM directly onto the camera. I love Velcro......................

Going to experiment also with placing a stock SS fuselage square tube over a piece of CF to see how that will work for tailboom. Too late to use on this aircraft, but will give some info for future modifications on the next.

Have not heard from anyone as to whether or not they might be going to the AMA Convention in Ontario CA. I still plan on attending tomorrow, so if anyone else is going to be there, let me know. Later..............................

Joe
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Old Jan 17, 2006, 02:15 PM
American MoonMan
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United States, CA, San Diego
Joined Jul 2003
2,722 Posts
Group,

Painted parts of the inside of the shop today. Still some painting to do, but did get my ChromaKey Blue wall done. Below is an example of it in use. Will post photos of the setup in a little while, but here is the result of a quick session. Later.......

Joe
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Old Jan 17, 2006, 02:39 PM
American MoonMan
Joe Bennett's Avatar
United States, CA, San Diego
Joined Jul 2003
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Group,

Here is a photo I just took of the setup for the previous one. Back wall is painted for BlueScreen, and table covering is a ChromaKey Blue backdrop. Aircraft of course is the SSV2. I now need to do some lighting installation so that I have even coverage to avoid hotspots and shadows. Once that is done, I can do stills or videos in front of the screens and do some very interesting things. Later..................

Joe
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Old Jan 17, 2006, 03:28 PM
American MoonMan
Joe Bennett's Avatar
United States, CA, San Diego
Joined Jul 2003
2,722 Posts
Group,

Since my last message above, I have done a bit of traveling. Later....

Joe
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Old Jan 17, 2006, 07:48 PM
Beam me up Scotty
Vette's Avatar
Central Ohio
Joined Dec 2002
550 Posts
It is too bad you didn't have your camera mounted on the plane on those trips, you could have had some awesome aerials....
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