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Strobe wires.

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pacificpainting(at)comcas
Guest

Posted: Fri Sep 08, 2006 8:14 pm Post subject: Strobe wires.

I plan on running the strobe wires through the  leading edge ribs on my 801. Any reasons for or against?

  

 Dave in Salem

 801

   [quote][b]

p.mulwitz(at)worldnet.att
Guest

Posted: Fri Sep 08, 2006 8:58 pm Post subject: Strobe wires.

Hi Dave,



 That wouldn't work very well on a 601, but I don't know about the 801.  The 601 has fuel tanks on the inboard half of the nose rib area.  They would get in the way of the strobe wires.



 One question:  Will you install the power supplies for the strobes at the wing tips or in the fuselage?  If you are running the wires that connect the power supplies to the actual strobe lamps all the way down the length of the wings, I would recommend shielding them.  That means putting them in a conductive sleeve of some sort with one end (probably the fuselage end) grounded to the frame and the other end floating electrically.  The idea is to keep the high voltage impulses away from your radios and antennas.



 Best regards,



 Paul

 XL fuselage



 

 At 09:13 PM 9/8/2006, you wrote:

  	  Quote: 	
		  I plan on running the strobe wires through the leading edge ribs on my 801. Any reasons for or against?

  

 Dave in Salem

 801

 	
 

 ---------------------------------------------

 Paul Mulwitz

 32013 NE Dial Road

 Camas, WA 98607

 ---------------------------------------------

     [quote][b]

pacificpainting(at)comcas
Guest

Posted: Fri Sep 08, 2006 9:33 pm Post subject: Strobe wires.

Hi Paul,

  

 I have 2 tanks per wing and they are located behind  the main spar. There is nothing between the leading edge of the spar and the  nose skin except a lot of room. I am mounting the strobe power supplies to the  spar tips and running the strobe and nav light wires through the wing to a  switch. I think I will also run a ground wire along with them instead of  grounding to the wing structure. I don't know if it makes any difference, but  it's easy to do at this stage and it can't hurt anything. I'm always curious how  other people do things and this is a good group to pick up a lot of useful  information.

 Thanks for the input.

  

 Dave in Salem

 801

  

  

 [quote]   ---

roger(at)nwtradingpost.co
Guest

Posted: Fri Sep 08, 2006 11:14 pm Post subject: Strobe wires.

Dave   

   

I am building a 701 just to the north of you and went through the same set of questions with the strobes before I finished my wings  

   

The advice that made the most sense to me was to mount the power supplies in the fuselage (behind the seats in the 701) and run shielded cable from here out to the strobes on the wing tips  

This has 2 main advantages, 1. it makes it easier to maintain/replace the power supplies, and 2. it takes the weight out of the wing tips and puts it lower down in the fuselage  

   

I called Aeroflash in Chicago and they were perfectly happy with this and supplied me with the shielded cable. I will be using Molex connectors at the wing root and the short piece of exposed wiring at the connector is also no problem, so they tell me as long as I also connect the shielding. As Paul says, ground the power supply side of the shielded cable, not the outboard end  

   

I have been following your project with interest  

   

Roger   

   

701, busy on flaps and slats  

Kenmore, WA        

  

From: owner-zenith-list-server(at)matronics.com [mailto:owner-zenith-list-server(at)matronics.com] On Behalf Of Dave Ruddiman

 Sent: Friday, September 08, 2006 10:33 PM

 To: zenith-list(at)matronics.com

 Subject: Re: Strobe wires.  

  

     

Hi Paul,  

    

   

    

I have 2 tanks per wing and they are located behind the main spar. There is nothing between the leading edge of the spar and the nose skin except a lot of room. I am mounting the strobe power supplies to the spar tips and running the strobe and nav light wires through the wing to a switch. I think I will also run a ground wire along with them instead of grounding to the wing structure. I don't know if it makes any difference, but it's easy to do at this stage and it can't hurt anything. I'm always curious how other people do things and this is a good group to pick up a lot of useful information.  

    

Thanks for the input.  

    

   

    

Dave in Salem  

    

801  

    

   

    

   

  [quote]    

---

p.mulwitz(at)worldnet.att
Guest

Posted: Sat Sep 09, 2006 2:21 am Post subject: Strobe wires.

Hi Dave,



 I chose the other route for the ground path.  I am using the wing skin and structure for the ground return path for the strobe supplies.  I also chose not to use any paint on my internal joints for corrosion control, so I have a really nice electrical connection between all the structural parts.  Aluminum is not as good a conductor as copper or silver, but there is so much of it I think it should make a superb ground path.  To prevent radio noise, I intend to run a heavy copper ground wire from the common ground point near the engine to the instrument panel.



 I realize this is a controversial approach, but I am reminded of a popular saying from the designer of the MiniMax I built about 20 years ago.  His comment was -- if you are thinking of adding anything to the structure, try throwing it up in the air.  If it comes back down, it is too heavy.



 Given the location of your fuel tanks, the nose area of the wing sounds like a perfect place to route the wires.  The next question is whether to install some sort of conduit for them or route the wires through the nose ribs using grommets or some sort of trellis in the lightening holes.  



 I chose to skip the conduit (see the test above) and used lacing tape to bind the wires together.  The idea is to keep the wires reasonably tightly suspended so they don't rattle around when flying in bumpy air.   I had a hard time doing this until I discovered lacing tape.  It is like dental floss but a bit larger and covered with a lot of wax.  The method I found worked best for me was to route the bundle through a rubber grommet and tie it on both sides of the rib through a hole drilled next to the grommet - perhaps 1/4" from the rubber.  The resulting "U' shaped cord seems to do a good job of holding the bundle in place.  The lacing tape is available from AS&S and is the only stuff I have found that actually sticks (a little) to the Tefzel insulation on aircraft grade wire.  The alternative of using nylon cable ties seems good until you discover that the wire just slips right through the tightly pulled ties -- making it impossible to really fix the wire bundle in place.



 One other thing I decided to do was install connectors on all the wires at the wing root.  This allows removal of the wing without cutting the wires.  I opted for automotive spade connectors with nylon covers and use a little more of the lacing tape to tie the connectors together to make sure they don't slip apart.  I have heard some people say not to use automotive connectors, but I have no idea why not.



 Good luck,



 Paul

 XL fuselage



 



 



 

 At 10:32 PM 9/8/2006, you wrote:

  	  Quote: 	
		  Hi Paul,

  

 I have 2 tanks per wing and they are located behind the main spar. There is nothing between the leading edge of the spar and the nose skin except a lot of room. I am mounting the strobe power supplies to the spar tips and running the strobe and nav light wires through the wing to a switch. I think I will also run a ground wire along with them instead of grounding to the wing structure. I don't know if it makes any difference, but it's easy to do at this stage and it can't hurt anything. I'm always curious how other people do things and this is a good group to pick up a lot of useful information.

 Thanks for the input.

  

 Dave in Salem

 801

  	
 

 -    [quote][b]

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sat Sep 09, 2006 4:44 am Post subject: Strobe wires.

the DC wires for the nav lights  won't require the shielding. If you use the shielded wire for that application  you may add a few ounces to your plane.  Obviously you are aware the wires  to the strobe lights themselves are another ball of wax.  Grounding the  shielding at one end only, usually the inboard end, is a common avionics  practice.  That practice will even be carried to the much shorter  interconnects between various radios, audio panels and display  indicators.

  

 I think the important thing  with wires running through the wings is to make sure the wires are supported  properly in cushion clamps so they can't interfere with any flight controls or  rub against any structural members.

  

  

 

Noel [quote]   

   --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sat Sep 09, 2006 5:06 am Post subject: Strobe wires.

The guy who first thought of  using nylon wire ties should be flogged severely with a wet cod  fish!

  

 Unless the ends of these  ties have been properly sanded after the excess has been removed, they are  the worst hand gashing items ever inflicted on aircraft.  So far I haven't  heard of any one being sliced open by waxed string.  It may take a bit  longer to install but for the application it works a lot better.  For  heavier applications use Coraseal... its heavier and can stretch to keep things  nice and taught.

  

 As for using the aircraft skin  for a ground shield nope.... no way .... nada.  the skin will form a huge  capacitor with the positive charged wires running through it.  This is why  shielded wire is only grounded at one end.

  

 They say for metal to  corrode two things are required; two dissimilar metals and moisture ( salt  water makes a better electrolyte).  But you may have noticed how the  battery terminals on your car will corrode unless they are covered with a good  quality of grease.  What do you think will happen when you attach copper  wires to a nice aluminium skin and run a current through it and then to top  things off go playing in the clouds???  A better  idea... use a  shielded wire grounded at one end only or for a DC current like the nav lights a  two conductor cable. 

  

 There are places where an  aircraft frame, like that of a car will provide a common ground.  Usually  that occurs in the 4130 steel sub frames of many planes.  even when this is  done extra grounding straps are usually installed to supply current to high  drain devices like starting motors.

  

 

Noel [quote]   

   --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

rstone4(at)hot.rr.com
Guest

Posted: Sat Sep 09, 2006 5:10 am Post subject: Strobe wires.

Dave,

      If you do, be sure  to install rubber grommets in each hole.  Vibration will soon cause a dead  short to ground when the sharp edge of hole wears through the insulation.   Another way to protect wiring is, install a plastic tube first using bulkhead  seal at each hole, then run your wires through the tube.

  

 Bob Stone, Harker Heights, Tx

 ZodiacXL

 [quote]   ---

stutzman(at)stutzman.com
Guest

Posted: Sat Sep 09, 2006 3:37 pm Post subject: Strobe wires.

On Sat, 9 Sep 2006, Roger Venables wrote:

 	  Quote: 	
		   The advice that made the most sense to me was to mount the power supplies in

 the fuselage (behind the seats in the 701) and run shielded cable from here

 out to the strobes on the wing tips



 This has 2 main advantages, 1. it makes it easier to maintain/replace the

 power supplies, and 2. it takes the weight out of the wing tips and puts it

 lower down in the fuselage


	


Well, I don't think I disagree, but here is an opposing point of view

anyway 



If you are going to add weight to a plane, the wing tips arn't such bad

places (within reason).  One simple reason is that usually puts that

weight right on the longitudal center of gravity.  Another is that putting

the weight out there reduces the bending moment of the wing.  Notice all

the planes with after market tip tanks?  Those STCs also usually include a

gross weight increase that stipulates that any weight over the original

gross weight must be carried in fuel in those tip tanks.  Yet another

reason is that some strobe power supplies generate rf noise that isn't

always easy to shield and putting those supplies out on the tips can

mitigate this problem to a bit.



Your point about ease of maintenace is very valid, but I've seen some

clever access panels done on the tips of a 701.



Frank Stutzman

Bonanza N494B     "Hula Girl"

Hood River, OR

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sun Sep 10, 2006 5:39 am Post subject: Strobe wires.

Re weight on wingtips:

How about how having weight at the wing tips in relationship to spin

characteristics.  Also...In the case of wing tip tanks how about if one tank

is full and the other is three quarters full???  

Re: flasher unit installation

Now days the flasher units are getting down to mere ounces and if your wing

design will allow you to install and service without the use of a crowbar

the outboard weight would be insignificant.



Noel



[quote] --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

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