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  #1  
Old 02-17-2009, 11:13 PM
SportAvServ SportAvServ is offline
 
Join Date: Jul 2006
Location: Ione, California
Posts: 175
Default Piper Pitot

Does anyone have a wiring schematic for a piper blade type heated pitot? I know it seems simple enough but I would like to see just how Piper did it with wire and breaker size. Any info would help.

Randy
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  #2  
Old 02-17-2009, 11:59 PM
gasman gasman is offline
 
Join Date: Mar 2007
Location: Sonoma County
Posts: 2,704
Default

Quote:
Originally Posted by SportAvServ View Post
Does anyone have a wiring schematic for a piper blade type heated pitot? I know it seems simple enough but I would like to see just how Piper did it with wire and breaker size. Any info would help.

Randy
PA28-161........ wire used 14 ga with a 15a breaker per PIPER SERVICE MANUAL.
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  #3  
Old 02-18-2009, 08:43 PM
SportAvServ SportAvServ is offline
 
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Location: Ione, California
Posts: 175
Default pitot

Thanks, Gasman, that will help.
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  #4  
Old 03-19-2009, 11:39 AM
chaskuss chaskuss is offline
 
Join Date: Mar 2005
Location: SE Florida
Posts: 1,248
Default Piper Pitot Heater element info

Your Piper Pitot has not one but two heater elements. They differ in power draw (70 watt & 100 watt ratings). I would suggest using a double pole switch, so that you can have a separate fuse & switch for each heater element. I can supply a CAD drawing of how I'm doing this.
RV-9A builder Peter Laurence loaned his Piper pitot to an experimental aircraft electrical vendor for examination. The vender wanted to see if he could offer repair of these units. Peter's pitot (functional when it left) came back damaged from the vendor. He did the research and found that replacement elements are available. This makes one more reason I prefer the Piper unit compared to the Cessna style. See info below.

Heaters are made by Hotwatt Http://www.hotwatt.com/cartridg.htm


Hotwatt part #s
For pitot: 13A7025 70W 12V
static 13A7026 100W 14V


Piper part #s
464-356 for the 70W 12V
464-357 for the 100W 14V


These are called cartridge heaters. They are 3"X 3/16"
and 4"X 3/16"


Check the ceramic plug where the wire enters the cartridge. If there's any movement of the wire, it should be
replaced.
Peter

Charlie Kuss
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  #5  
Old 11-02-2011, 10:18 AM
Martin Sobel's Avatar
Martin Sobel Martin Sobel is offline
 
Join Date: Feb 2006
Location: Sarasota, Florida
Posts: 11
Default Piper Pitot Overhaul

Does anyone have suggestions as to how to extract the old heaters.

Also, I assume the 3" heater goes to the front of the blade?

Martin Sobel
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  #6  
Old 11-21-2011, 06:18 PM
Martin Sobel's Avatar
Martin Sobel Martin Sobel is offline
 
Join Date: Feb 2006
Location: Sarasota, Florida
Posts: 11
Default DRILLING OUT HOLES FOR CARTRIDGE HEATERS IN “PIPER” HEATED PITOT

While attempting to attached power and ground wires to the “Piper” Heated Pitot I’ve had for some time, one of the leads broke off one of the cartridge heaters. Both of my heaters were inserted a bit too much to get a grip on either of them.

At that time I did not realize that the heaters could possibly slide out of the head. A little research with the Van’s Air Force Group led me to the following:

It is possible to slide the heaters out with no or some minimal force.
Heating the head with a propane torch, allowing the heat to transfer thru the head does loosen up the cartridge, allowing it to be pulled out of the head. Some twisting of the head might help. It might be a good idea to remove the Pitot and Static fittings from the head to allow a needle nose pliers to get a grip on the cartridges. Be careful not to damage the leads coming out of the cartridges.

If it becomes necessary to drill out the cartridges, I suggest the following:
Use a 5/32” IRWIN Hammer Drill Bit to cut thru the ceramic center of the cartridge. This bit is about 6” long. A normal air drill works fine.

Follow up with a #13 Cobalt Aircraft Extension 6” long. This will clean out the hole and will leave a hole large enough for the cartridge. It may be necessary to follow up with a 3/32 Chucking Reamer. In my case the #13 drill made the hole just right. Needless to say, be careful that you do not make the hole deeper than it was.

As I got into this project, I realized that I needed 28V elements because my aircraft will have a 28V system. I was able to get these cartridges thru McFarlane. These cartridges are available at very reasonable prices and I did not have to order three of everything (some mixing and matching allowed) from the manufacturer.

McFarlane Aviation, Inc.
696 E. 1700 Road
Baldwin City KS 66006
www.mcfarlandaviation.com
sales@mcfarlandaviation.com
800-544-8594
CA464-440 PITOT HEATER ELEMENT 28V 70W
CA464-441 PITOT HEATER ELEMENT 28V 100W

The question remains as to how to hook up the cartridges. Piper runs them in parallel connected to a single source wire. With this arrangement it is not easy to notice a failure in one element until they both fail. A short in either element will cause both to fail Seems to me that two wires running to a split [double pole, single throw] switch, with separate fuses/breakers for each element, would make a more logical arrangement.
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  #7  
Old 11-21-2011, 06:48 PM
aerhed aerhed is offline
 
Join Date: Dec 2008
Location: Big Sandy, WY
Posts: 1,967
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If your ammeter is wired like a piper, you can note the pitot amperage and if it drops, you've lost one. Kinda like you do with prop heaters.
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  #8  
Old 11-22-2011, 08:19 AM
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KatieB KatieB is offline
 
Join Date: Jun 2010
Location: Zeeland, MI (Z98)
Posts: 706
Default

All I could think of when I read this thread title was,
"Peter Picked a Piper Pitot..."

Say that fast a few times! (Sorry, my morning Red Bull is finally kicking in!)
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