[N787R]

I have flown for about 25 years and rarely I turned pitot heat on. I always avoid icing conditions.
Now that I am building my own and equiping it for IFR flight, I am not sure if heated pitot will be in my equipment list.
Whats your opinion?

Regards

B

 

[Kevin Horton]

If you will fly IFR above the freezing level, then you should have pitot heat. If you will always stay below the freezing level, then you don't need it. Pitot tubes are likely a more efficient ice collector than the wing, due to the smaller radius at the leading edge of the pitot tube. So, you could be collecting ice on the pitot tube when nothing can be seen collecting on the wing.

Even if you plan to avoid icing conditions, once you stick your head in a cloud above the freezing level, you never know what you will find.

 

[Bob Axsom]

I wouldn't be without it but ...

I tookoff from Palm Springs one night and flying through Banning Pass in the dark of night between the mountains, IFR, in the clouds in my Archer II the pitot froze and the airspeed dropped to zero. There was no panic at all. The sound, attitude and altitude were plenty adequate to maintain confident control until the pitot heat cleared the airspeed problem. In the RV-6A I may not be so confident but I suspect the sensation would be similar. I have never had the experience in it. I have never waited so long before turning on the pitot heat since that night.

Bob Axsom

 

[atreff]

I think so

Behnam,

I am building a full IFR RV with ER Tanks for long distance travel. I fly approx 200 hrs/yr on business in a store bought plane which has pitot heat. I turn it on every time I enter clouds, even if the air temp is above freezing. Why? If I stumble into a thunderstorm accidentally, I could be in a hurt locker, especially if my pitot/stat system is inop. Also, I try to do everything the same way when I fly IMC. So, in the goo, it's Pitot heat and carb heat on. I used to not pull the carb heat and then one trip from Ottawa, Canada to Boston, I was in the clag with moderate rain over northern Vermont, and suddenly the O-360 starts dying on me. Carb heat on, and it took aboutr 3 very loooooong minutes to clear. But you asked me about pitot heat. Sorry.

Pitot heat-easy to install, run one wire out in the wing, a switch and a fuse/CB and you're done. I too never intentionally go out in icing conditions. But, to me that one extra circuit installed is insurance. I went with a Piper type pitot/static mast so both are heated, as I had my static port freeze twice in the winter in the Northeast.

Say you're flying in the clear above an overcast in your RV and you need to suddenly get down-rough engine, sick passenger, worse headwinds than anticipated so you'r burning more fuel and now it's later than expected and you have to shoot an approach to an airport with temps close to freezing. None of us plan these scenarios, but sometimes in a pilot's lfe they arise. Flipping on the pitot heat will assure that at least your airspeed and altimeter will be valid even if your airframe ices up on the approach.

Just my 2 cents.

Art in Asheville, NC (the icy mountains)

 

[L.Adamson]

Depends on $$$

When I purchased mine, in the late 90's, it was "cheap". About $300 total for the heated pitot & mount. And it's good looking too!

But now the same model is $1800+, which does not include the mount.

So for me, it was definately worth it. But I'd never spend the money for the new price; although I know you can get cheaper ones.

L.Adamson

 

[Kevin Horton]

I went with a Piper type pitot/static mast so both are heated, as I had my static port freeze twice in the winter in the Northeast.

Art - Where was the static port on the aircraft that you had it freeze over?

 

[atreff]

Frozen static port

Kevin,

Good to hear from you again. I"ll call when I'm up in YOW again. The frozen static port was on a '66 mooney, and the port is back in the tail. AC was on tie down, not a hangar, and it was Connecticut where visible humitidy is pretty common in the winter months.

After that occurrence, during the preflight (this will sound gross) I would suck on the static ports...surprising how much water I got out. Yes, Mooney installed a drain, but it was not effective. Now I understand why bizjets have heated static ports.


Art

 

[Kevin Horton]

I wonder if moisture was freezing in the static line, or if the port itself was somehow freezing over. I'm betting on the first option, as I have a hard time imagining how ice could collect on a rear fuselage mounted port. Moisture freezing in the static line is a risk no matter whether the static port is heated or not. I think Van's recommendation to run the static lines up from the ports to the top of the bulkhead should help ensure that no moisture collects in the static system. Time will tell.

Be sure to do a good check of the static system position error, as there is a significant probability of errors with your non-standard static system. If you end up with errors, you could try putting tapered shims under the pitot mast to change the angle that it leans fore and aft, which will change the pressure seen at the static port. It may take several tries to find the optimum shim taper.

I'm hoping you'll fly the RV-8 up here once you get it flying. I'm looking forward to seeing how the fastback mod turned out.

 

[craigvince]

Source for heated pitot tubes?

Does anyone have any good leads on buying heated pitot tubes?

 

[lucky333]

I got a Falcon one..

..at OSH a couple of years ago, for about $400 including the bracket. I'm not a fan of Chinese anything but it looks well made and gets hot when power is applied. Looks like what's used on a Cessna. The heater is a cartridge element that unscrews for replacement. Model number 12-AN-5812.

Haven't flown it yet.. Their gauges don't get good reviews. Hopefully, its pretty hard to screw up a tube..

Link

John

 

[the_other_dougreeves]

I noticed the pitot/static on the Katana for the first time last week - an interesting design. More of a blade (think XPDR antenna) than a mast or traditional "stick". I'd be curious to see if it behaves better in icing.

TODR

 

[Kevin Horton]

I noticed the pitot/static on the Katana for the first time last week - an interesting design. More of a blade (think XPDR antenna) than a mast or traditional "stick". I'd be curious to see if it behaves better in icing.

The Katana uses a "Piper" pitot mast. I was an interested observer to the development of the DA-20C model. One of the changes was a redesign of the wing spar, which moved it to a slightly different position inside the wing. The new position interfered with the old location of the pitot mast, so they had to move it slightly. Once they got the prototype flying, they found that they now had quite large static system position errors, which affected the airspeed and altitude accuracy. So, they launched into a flight test program to find a solution. They tried all the different part numbers for the Piper pitot masts, but none of them gave acceptable results (each part number has a different angle on the bottom face, which affects the pressure seen at the static port). We jokingly suggested that they market one of them as the high performance option, as it gave IAS at the stall that was very low, and an IAS in cruise that was about 15 kt too high. They eventually resorted to a probe with a custom angle on the bottom face to get acceptable accuracy.

The Katana is not approved for flight in icing, or even IFR (it would have been too expensive to add lightening strike protection to the design). So it would have to be an awful bad day, or a very crazy pilot, before the pitot tube ever saw any ice. The Piper pitot tube would ice up like any other pitot tube, if there was no pitot heat, and icing conditions were found.

Objects with a sharp radius at the leading edge (like pitot tubes) are much more likely to collect ice than objects with a large radius (like the wing). This is because the tiny little super-cooled water droplets that cause ice are carried in the air as it moves around the aircraft. If the air is going around an object with a large radius, the air bends smoothly around, carrying the water droplets with it, and they don't impact the surface. But, if the object was a sharp radius, the air bends sharply, and the water droplets can't follow the air due to their inertia. They hit the surface and freeze, creating ice. Of course even the wing will ice up, if the droplets are large enough, as the larger droplets have enough inertia to hit the surface.

So, you could be collecting ice on the pitot tube, even if no ice is collecting on the wing.

 

[frankh]

What about the fuel tank vents?

My Pitot froze over once...No big deal as it was daytime and easy (bkn cloud) IFR...But it did cause me to wonder how close are the fuel tank vents from freezing if the pitot already has?

Frank

 

[Kevin Horton]

My Pitot froze over once...No big deal as it was daytime and easy (bkn cloud) IFR...But it did cause me to wonder how close are the fuel tank vents from freezing if the pitot already has?

This is why some folks have put a small hole on the back side of the tank vents. No ice should collect there.

I'm not sure how big the hole would need to be to ensure adequate airflow. I'm pondering testing the adequacy of my hole size by deliberately blocking one vent, then switching to that tank while circling the airfield at max cruise power. A half hour test should be long enough to prove the vent hole on the backside was big eough, assuming the tank is full (worst case, due to small air volume in the tank).

 

[atreff]

Pitot mast mounting and static ice.

Be sure to do a good check of the static system position error, as there is a significant probability of errors with your non-standard static system. If you end up with errors, you could try putting tapered shims under the pitot mast to change the angle that it leans fore and aft, which will change the pressure seen at the static port. It may take several tries to find the optimum shim taper.

Kevin,

Good call. I talked to Dick Martin who said he had no p/s errors in his -8, so I copied his mount location for the piper pitot/static mast. As you know, I ain't flying yet, so time will tell.

As to the Mooney's freezing static, I know it was in the lines, because the day was CAVU, no ice was on the ports, and the temps were below freezing. As soon as I took off, the altimeter didn't move and the VSI and airspeed were pretty strange....

Art in Asheville.

 

[tomcostanza]

As a student, I had a pitot freeze, apparently from some dew that collected in an unheated pitot. I didn't notice it during preflight, but a few minutes after takeoff, the ASI went screwey. Made for an interesting landing!

I bought a 24v heated pitot on eBay. I tested it by filling it with water and taping the ends. Then put it in the freezer until it was frozen solid. Then I connected it to 12v and timed how long it took for the ice to melt. It melted in about 35 seconds. I figure this will be good enough, and the pitot cost $50. So for less than $200 including the mount, I think it's worth it. Plus, now all the infrastructure is in place if I ever want to "upgrade".

Clear skies,

 

[Lycosaurus]

12V on 24V pitot is 1/4 power

I bought a 24v heated pitot on eBay. I tested it by filling it with water and taping the ends. Then put it in the freezer until it was frozen solid. Then I connected it to 12v and timed how long it took for the ice to melt. It melted in about 35 seconds. I figure this will be good enough, and the pitot cost $50.

What your test omitted was 150 mph freezing airflow/water vapour over the pitot. The heater has to overcome the freezing temperature, as well as the cold air and super cooled water droplets that freeze in your pitot. It must also melt any previously accumulated ice under those conditions.

By using 12V instead of 24V, your pitot heater is running at 1/4 power. It may work in the freezer, but not in a freezing airstream I suspect.

I'm sure pitot heaters have some level of design margin built-in, but not to the extent of tolerating a 75% power loss.

There's the Gretz pitot tube, Dynon, and Falcon, all at about $400. The certified one has gone as high as $1200 or so, and I see that it seems to be at around $800 or so now.

I got lucky and found 2nd hand 12V unit, otherwise I would have gone with one of the non-certified versions above.

Just my $.02

P.S. just realized that you may just be using the pitot heat to de-ice your pitot on the ground, then that will work. Just cautioning not to count on it in flight under icing conditions.

 

[AZtailwind]

and another

..at OSH a couple of years ago, for about $400 including the bracket. I'm not a fan of Chinese anything but it looks well made and gets hot when power is applied. Looks like what's used on a Cessna. The heater is a cartridge element that unscrews for replacement. Model number 12-AN-5812.

And Yep, I've been thinking about the Falcon model or the Dynon:
http://www.dynonavionics.com/docs/news_AOA.html

If I go the EFIS, that would make a good companion, that is just my thoughts though FWIW. No experience these products, just putting my thoughts on pape... er... uh screen...yea..