Blade Pitot Input

ww2planes · #1 02-19-2006, 08:27 PM

Has anyone installed a blade style pitot? Are there any problems with using one on a RV? I like the look a lot better and have already purchased one. Polished it and it really looks good. Any input would be greatly appreciated.

Ironflight · #2 02-19-2006, 08:53 PM

I am using a Piper blade-style pitot on my RV-8, and love it! It's been knocking about in my box-o-airplane-parts for years, ever since I rented my first hangar, and found that the last guy had left a bunch of stuf in the shelves. When I started the RV-8, I priced heated pitots and nearly fainted! For what I was going to have to pay for a new one, I figured I'd risk the pitot ice! Then I remembered that blade...I dug it out, connected it to 12 volts, and sure enough, it got hot! OK...first piece of extra equipment checked off the list!

Based on what I heard from numerous folks, you don't want to use the static ports on the blade - they lead to significant errors. Use the pitot only, and the standard van's static locations on the fuselage. I have excellent airspeed calibration, and in my opinion, it does look cool...

One caveat - I think I have read that there are several different Piper blade pitots, but I think one type is the most common, and that is what I appear to have. Not sure if they all work as well.

Paul

vlittle · #3 02-19-2006, 10:18 PM

Quote:

Originally Posted by ww2planes

Has anyone installed a blade style pitot? Are there any problems with using one on a RV? I like the look a lot better and have already purchased one. Polished it and it really looks good. Any input would be greatly appreciated.

I have a Dynon Pitot/AOA mounted on my -9A. I'm having some airspeed calibration errors.

Today, I calibrated my static system/altimeter, and my airspeed (through the static system with the pitot at ambient pressure). On the ground, everything is within 1% or so after fixing a math error (blush).

In the air, however, I'm getting an indicated stall speed about 5 knots high, and an indicated cruise speed 5 knots low. I suspect a pitot system leak (not likely) or a pitot position error (may be too close to the wing pressure wave?). I don't think it's a static position error because I'm using the Van's stock locations.

Anyone else with a Dynon in a -9A that has calibrated their system on the ground and in the air, please let me know your experiences.

Vern

gmcjetpilot · #4 02-20-2006, 01:48 AM

Quote:

Originally Posted by ww2planes

Has anyone installed a blade style pitot? Are there any problems with using one on a RV? I like the look a lot better and have already purchased one. Polished it and it really looks good. Any input would be greatly appreciated.

I hate asking the obvious (may be not so obvious), but I can't stand it, why do you want a heated pitot tube at all? I know it sounds stupid, especially from a CFI-I-ME, ATP with a few type ratings, but why do you want a heated pitot on a single engine sport plane that is prohibited from being in icing conditions. Do you plan on flying in icing?

I don't begrudge people building what they want, but I wounder sometimes why so many want a heated pitot. I really don't get a VFR pilot needing a heated pitot on their plane. Even IFR, ice should be a rare event, at least if you plan your flights right, i.e. safe and legal.

They are expensive, draw copious current add weight and the amount of time you might use it, is......well questionable. I relize many are drawn to them because they like the looks, since the standard "TUBE" is plan, although arguable very functional, light and inexpensive. Make a fake one out of fiberglass or metal of any cool shape you want for a few bucks.

Lets go out on a limb (and you would be). You find yourself in icing conditions.

Some how it gets so bad your pitot is blocked and thus your airspeed indicator is dead. You still have approximate speed from GPS ground speed. Of course you're solid IMC now, on instruments. You need to get out of it NOW, both from a common sense and legal stand point, right. In my opinion (and the FAA's) if you're getting airframe ice you are not only illegal you are in a dangerous condition, even with pitot heat. Once you see ice it is "KNOWN ICE", at least now.

How do you get ICE? Any takers?

Ans: Visible moisture and temp below 0 C. Period end of story. Stay out of clouds or temps below 0 C (and above -40 C) no ice. If there is no clouds, mist, fog (defined as visibility of say less than 1 miles) no ice. If temp is above 0C no ice. It is that simple. NO ICE. You can't form ice unless you are in a cloud below 0C. (Below -40C there's not enough moisture to cause icing.)

Someone might say "freezing rain" (I coverd it with visible mosture). If you are in freezing rain, you're in trouble. Don't worry about the pitot. You'll have no lift or thrust when the wings and prop ice over. In this case heated pitot will only help you to see indicated airspeed on the way to the scene of your crash.

If you plan on flying IFR routinly than the value of a heated pitot is better justified, but its not required IFR equip! I am surprised how much effort and expense builders put into a heated pitot for VFR RV. If you are a VFR pilot and wondering into clouds in freezing conditions, you have more troubles than pitot ice.

Suggest builders evaluate if they really (really) NEED a heated pitot. If not sure, run some wires out the wing and put in one of those fake heated pitot ( http://www.gretzaero.com/ga500.html ). You can replace it later with a hot one, if you so decide. Just a suggestion but if you have to have a heated pitot you have to have it. However weight on RV's is important and the lighter the better. Its just a thought.

George

n468ac · #5 02-20-2006, 03:05 AM

1. Dynon issue ... we had your Dynon off 10 to 15 kts off with full flaps down ... found a pintched pitot tube going to the unit ... after replacing the tube everything worked on the mark.

2. Heated pitot ... We currently don't have a heated pitot, but are now going to install one. After flying in very light rain, we put her away. During the next week it got below frezzing ... the next time, i started my take off roll the air speed was dead! After taxing back to the hanger and three days of heating different parts of the plane ... i heated the pitot over night and it drained. If i had been off my home field this could have really put a damper on getting home. If we had a heated pitot this may not have happened.

Deuskid · #6 02-20-2006, 06:31 AM

Quote:

Originally Posted by gmcjetpilot

I hate asking the obvious (may be not so obvious), but I can't stand it, why do you want a heated pitot tube at all? I know it sounds stupid, especially from a CFI-I-ME, ATP with a few type ratings, but why do you want a heated pitot on a single engine sport plane that is prohibited from being in icing conditions. Do you plan on flying in icing?

I don't begrudge people building what they want, but I wounder sometimes why so many want a heated pitot. I really don't get a VFR pilot needing a heated pitot on their plane. Even IFR, ice should be a rare event, at least if you plan your flights right, i.e. safe and legal.

They are expensive, draw copious current add weight and the amount of time you might use it, is......well questionable. I relize many are drawn to them because they like the looks, since the standard "TUBE" is plan, although arguable very functional, light and inexpensive. Make a fake one out of fiberglass or metal of any cool shape you want for a few bucks.

Lets go out on a limb (and you would be). You find yourself in icing conditions.

Some how it gets so bad your pitot is blocked and thus your airspeed indicator is dead. You still have approximate speed from GPS ground speed. Of course you're solid IMC now, on instruments. You need to get out of it NOW, both from a common sense and legal stand point, right. In my opinion (and the FAA's) if you're getting airframe ice you are not only illegal you are in a dangerous condition, even with pitot heat. Once you see ice it is "KNOWN ICE", at least now.

How do you get ICE? Any takers?

Ans: Visible moisture and temp below 0 C. Period end of story. Stay out of clouds or temps below 0 C (and above -40 C) no ice. If there is no clouds, mist, fog (defined as visibility of say less than 1 miles) no ice. If temp is above 0C no ice. It is that simple. NO ICE. You can't form ice unless you are in a cloud below 0C. (Below -40C there's not enough moisture to cause icing.)

Someone might say "freezing rain" (I coverd it with visible mosture). If you are in freezing rain, you're in trouble. Don't worry about the pitot. You'll have no lift or thrust when the wings and prop ice over. In this case heated pitot will only help you to see indicated airspeed on the way to the scene of your crash.

If you plan on flying IFR routinly than the value of a heated pitot is better justified, but its not required IFR equip! I am surprised how much effort and expense builders put into a heated pitot for VFR RV. If you are a VFR pilot and wondering into clouds in freezing conditions, you have more troubles than pitot ice.

Suggest builders evaluate if they really (really) NEED a heated pitot. If not sure, run some wires out the wing and put in one of those fake heated pitot ( http://www.gretzaero.com/ga500.html ). You can replace it later with a hot one, if you so decide. Just a suggestion but if you have to have a heated pitot you have to have it. However weight on RV's is important and the lighter the better. Its just a thought.

George

Wow George - your next post is 1K....

I haven't read nearly all of them but those I have are always welcome. Thank you and all the other experienced posters here that make learning a joy.

John

vic syracuse · #7 02-20-2006, 07:06 AM

I do not want to get into a tit for tat here with George, but I would encourage the installation of heated pitot tubes for anyone who is going to fly IFR. Yes, it's nice to say we'll just avoid icing. The distances which we can cover at RV speeds will almost always allow for changing weather conditions along the route, especially unforecast ones in the middle of winter in the Great Lakes. A number of the glass cockpits we are installing require Pitot and static to the AHRS. Why risk everything going South when it is probably needed the most? I'd rather be on the ground in one piece explaining why I was in "known" icing (unforecast known icing to be exact) than have my heirs explaining it. Accidents are usually the result of a number of things piling up on the pilot.
For the record, I've used my pitot heat 3 times in 230 hours in the RV-10. Once at 16K' over the Sierras because a thin scattered unforecast layer had formed and I was picking up light rime and needed to climb out of it, once for a thin fog layer that moved onto the runway at Vail as I was taxiing out, and once because I was climbing through a layer at 40 degrees F. I probably didn't need it, but was glad it was there.
Yes, the prices of these things make a blind man want to see, but when it's needed, it's needed.
I hate ice more than thunderstorms, and I do my best to avoid it. As a matter of fact, we fly very little IFR in the RV-10 because we like to enjoy the trip and see the scenery. But the times the pitot heat has been needed, it was there, and instead of being a crisis, it was just another operational item, and another weather lesson, which we always seem to get.

The neat thing about these airplanes is that we all get to build them to best suit the way we as individuals will utilize them.
Vic

Ironflight · #8 02-20-2006, 07:11 AM

Very good question George, and the answer for me is simple....

Becasue I had one, it worked, it was free, and so...why not?

I seriously doubt that anyone is going to go buy a new one from a Piper dealer (once they find out the price) just to make their RV's pitot look cool...my guess is that the questioner had found one like I did, and just wanted to know if it would work.

I am not advocating that they are required or necessary for our airplanes, but under my situation, it was simple. Same logic as the Wig-Wag flap...it cost next to nothing, it MIGHT save you're life (if you were being inatentive in the first place), so how could you possibly argue against it?

But if I had to go spend $1000 for a new one? Well, I think it would be a lot lower on my list.... So in the logic of "necessity", we essentially agree.

Paul

ww2planes · #9 02-20-2006, 09:09 AM

Thanks everyone for the input. Most of it is not applicable as I never mentioned anything about a heated tube. I just want to know if anyone has any experience with the Piper Blade Style Pitot. Non-heated, non-dynon, just plain blade style pitot. If anyone has any input on this specific question I would love to hear it. Thanks everyone.

f1rocket · #10 02-20-2006, 10:39 AM

The guy who bought my RV-6 (non-heated pitot) used it as an IFR platform. He told me that occasionally, he used to get moisture in the tube and it would freeze.

I put a heated tube in the Rocket because I plan to get my IFR ticket, and I'd rather have it installed and not use it, rather than need it and can't install it.

I can't argue with George's arguments. He has far more experience flying than I ever will have. I usually side with the KISS principle. In this case, I didn't see it as much added complexity. Just another switch, which I had room for, and since I have adequate alternator capacity, that wasn't a concern either.