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  #11  
Old 02-20-2007, 09:06 PM
chaskuss chaskuss is offline
 
Join Date: Mar 2005
Location: SE Florida
Posts: 1,225
Default

Quote:
Originally Posted by jonbakerok
I also used a Piper pitot blade. It was a heck of a lot cheaper than any other heated pitot and it even includes static port heat.

Which brings me to my point. I used the static port on the blade and it worked fine, or at least good enough for me. It's accurate in level flight but in a power-on stall or full flap stall it indicates 45 MPH at the break instead of 50. Power-off, clean, it stalls at 55 like any other RV6.

However, I've read of other people using a Piper blade who had an error of as much as 20 mph even in level flight and had to switch to the standard static ports. The difference seems to be the angle at the bottom of the blade. I have no idea which one I've got or what model it came off of.

It looks like you didn't use the static port. Did you try and it didn't work in your case? We could compare the angles.
Jon,
The static port on the Piper "blade style" pitot tube works better if the pitot is mounted 8" rearward from the main spar. As noted by other listers, there are numerous differing part numbers for Piper blade pitot tubes. They differ in the angle on the bottom of the blade. This angle difference is to correct out, any static port error.
I plan to use the heated static port as a "heated back up" static source. I will correct any static error by changing the angle on the bottom of the blade. This will be simple to do by comparing the read out with the stock Vans static port readings. Changing the blade angle will correct any error.
FYI, RV-9A builder Peter Laurence discovered a source of reasonably priced replacement heating elements for these pitots.
Here is the info. Heaters are made by Hotwatt

Http://www.hotwatt.com/cartridg.htm

Hotwatt part #s


For Pitot: 13A7025 70 W 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 cartidge. If there's any movement of the wire, it should be replaced.

Charlie Kuss
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  #12  
Old 02-21-2007, 05:54 AM
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jonbakerok jonbakerok is offline
 
Join Date: Jan 2005
Location: Houston
Posts: 361
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Quote:
Originally Posted by chaskuss
Jon,
The static port on the Piper "blade style" pitot tube works better if the pitot is mounted 8" rearward from the main spar.
Not sure I buy that. Since the RV airfoil is rounded on the bottom, it would cause the pitot tube to be angled downward instead of directly facing into the relative air. I guess that might reduce the static error if the wrong blade was used but it seems to me like it would increase the pitot error, especially if you found you needed to switch back to the fuselage static source. Better to use the correct blade to begin with.

Mine works fine and it's mounted almost on the spar, very close to where Paul's is in his pictures. I used that location because it approximated the location on the Cherokee I was flying at the time. I don't recall seeing any part number on it, but if someone could verify that it's there somewhere, I might be willing to remove mine to take another look. Or maybe it would be enough to just measure the angle on the bottom.

I bought mine from Wentworth salvage. It came "reconditioned", meaning they had already replaced the heater elements. I didn't specify a part number, but just asked for a Piper pitot mast and got lucky. I think I paid about $100 (5 years ago).
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Jon Baker
RV6A sold, RV4 in-progress
Houston
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  #13  
Old 02-21-2007, 07:08 AM
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IowaRV9Dreamer IowaRV9Dreamer is offline
 
Join Date: Jan 2005
Location: Cedar Rapids IA
Posts: 992
Default

Quote:
Originally Posted by chaskuss
FYI, RV-9A builder Peter Laurence discovered a source of reasonably priced replacement heating elements for these pitots.
Here is the info. Heaters are made by Hotwatt
Http://www.hotwatt.com/cartridg.htm
Hotwatt part #s
For Pitot: 13A7025 70 W 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 cartidge. If there's any movement of the wire, it should be replaced.

Charlie Kuss
Hi Charlie - thanks SO MUCH for posting this great info. I just got my piper heated pitot from ebay and I noticed some wire movement. I want to address this before I mount the pitot.

Looking at the hotwatt site, I couldn't find the part numbers you referenced. I did find the SC18-3 and SC18-4 which are 3/16 x 3" and 4" standard cartrigde heaters (70 & 90 W). I don't think those are the right ones because they are rated at 3.5 Amps (max) from 120V.

Also, how are the heating elements attached in the mast?

Thanks for any info,
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Dave Gribble VAF #232
Building RV-9A N149DG (slider, O-320-E2A, IFR)
Restored and Flying Beech Super III N3698Q
Cedar Rapids IA

Ready for an engine!

There is no sport equal to that which aviators enjoy while being carried through the air on great white wings." Wilbur Wright, 1905
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  #14  
Old 02-21-2007, 07:45 AM
chaskuss chaskuss is offline
 
Join Date: Mar 2005
Location: SE Florida
Posts: 1,225
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Dave,
I purchased my heated pitot off of Barnstormers about 5 years ago for $75. I was lucky. Both heater elements work on my unit. My friend, Peter Laurence, purchased a used unit which was fully functional UNTIL he sent it to a vendor (initials PD) who wanted to inspect it. The vendor wanted to investigate copying this unit. For his kindness, Peter got his unit back damaged. :-( He did the research and repaired his unit. I suggest you contact him at plaurence@the-beach.net for more info.
Hotwatt does not have a search function that I could find on their web site. You might want to email them with the listed part numbers to see if they are valid.
Charlie
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  #15  
Old 03-31-2008, 03:28 PM
atreff's Avatar
atreff atreff is offline
 
Join Date: Jan 2005
Posts: 215
Default How to remove the elements in the piper mast?

Gents,

I searched on this thread and found it very useful. I need both elements replaced in my mast, but cannot figure out how to get them out of the mast? I've broken the wires off the elements trying to pry the cartridges out.

Any hints?

Art Treff
N666AT RV-8 Fastback
Flying
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  #16  
Old 03-31-2008, 03:37 PM
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atreff atreff is offline
 
Join Date: Jan 2005
Posts: 215
Default Oh, one more thing....on the Piper mast

I notice that my piper mast came from the salvage company with brass NPT fittings into the mast with barb fittings on the aircraft side. What type of hose does Piper use to hookup the mast?! Mine (like Paul's) melted hi temp polyurethane LeGris tubing within minutes when I powered up both elements.

Since I"m using both the static as well as the pitot fittings, standard AN flared fittings do not fit well between the elements. What have you guys done?

Also, I still would like advice on how to remove the cartridge elements.

And, according to Hotwatts' website, I can't find 13A7025 and 13A7026 in cartridge elements.

Art Treff
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  #17  
Old 03-31-2008, 04:51 PM
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IowaRV9Dreamer IowaRV9Dreamer is offline
 
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Location: Cedar Rapids IA
Posts: 992
Default Thought I'd posted this before, but...

I can't find it. You can get a rebuild kit from Air Parts of Lock Haven. Here is what you get for about $120:


As for removing the old heaters, I was able to pull mine out with pliers. They were held in by friction, dirt, and peened edges of the mast holes. The guy at Lock Haven told me to use the highest temperature silicone (Copper colored) to hold the new ones in. Just slide them in and goop the top. I recommend you do this after installing the tubing fittings, due to limited tool room.

I am using solid AN tube all the way from the wing root to the pitot tube. You can buy a fitting to go between AN and the tapered threads in the tube housing.


Hope this helps,
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Dave Gribble VAF #232
Building RV-9A N149DG (slider, O-320-E2A, IFR)
Restored and Flying Beech Super III N3698Q
Cedar Rapids IA

Ready for an engine!

There is no sport equal to that which aviators enjoy while being carried through the air on great white wings." Wilbur Wright, 1905
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  #18  
Old 03-31-2008, 07:06 PM
atreff's Avatar
atreff atreff is offline
 
Join Date: Jan 2005
Posts: 215
Default Thanks Dave

I'll pry mine out and stuff the new ones in. Thanks for the help.

Art
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  #19  
Old 10-06-2008, 04:10 PM
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atreff atreff is offline
 
Join Date: Jan 2005
Posts: 215
Default My Heated Pitot Mast rebuild

I checked Hotwatt and called them regarding their cartridge heaters. Lack of good information from them and fear of overheating/underheating the pitot/static mast, drove me to go the gen-u-wine piper replacement parts.

So, I called Airparts of Lockhaven and talked to their Pitot Mast rebuilding guy, who sez:

-Usually you cannot pull the elements out, he usually drills them out.
-Attachment backin the mast is staking on the outside of the element.
-The elements are rated up to 200C, so not many glues will hold it in.
-Standard aircraft rubber hose is all that is installed onto the barbed fittings screwed into the mast. (I confirmed this on a friend's Piper Arrow).
-Elements are wired in parallel, no high/low switch or resistors are used.
-The mast is designed to prevent ice while travelling at speed, do not power it up on the ground execpt for a few seconds, but it will not melt the hose
-Wires provided should not be shortened-they are 20AWG that is rated to 200C.-keep the 12" length provided onthe elements, at that length, standard butt splices/knife connectors can be used.

I did an experiment to confirm that the wires/hose will not overheat when powered up in flight. I immersed the bottom of the pitot mast in water and turned it on. To me, this simulates 200mph wind taking the heat away. Wiring stayed cool as did the hose and fittings.

As far as aftermarket elements, I'll tell you what was inked onto the cartridges in the Piper rebuild kit. Both are 3/16" diameter. One is 3" (3.25" if you include the part that sticks out of the mast when installed) the other is 4" (4.25").

3"
FastHeat JK
CS18545
70W 14V

4"
FastHeat JS
CS18543
100W 14V

I had no luck finding these part numbers on the Fast Heat website. I already have heaters working, so my research is done. If someone locates these Fast Heat pn's please pass them along to the rest of the group.

Art in Asheville
N666AT RV-8 Fastback
70+ hours.

The 3"
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  #20  
Old 08-11-2009, 12:41 PM
TClinton TClinton is offline
 
Join Date: Aug 2006
Location: Spruce Creek Fly-In, Florida
Posts: 14
Default Piper Pitot tube

Hi Paul, did you figure out which model of blade style pitot tube you used. I would also like to use the blade style pitot tube that Piper uses but have not been able to find a correct part number and source yet. I am building an F1 Rocket so the one you used should be perfect.
I would appreciate any advice you can offer. Regards, Tony
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