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JayH
09-27-2005, 07:18 PM
Just curious how most are mounting the pitot tubes on experimentals. A lot of the tubes I've looked at on certified 18's are cracking around the flange where it screws to the mounting gusset in the wing. I have a jury strut mount, but don't know if I like that either. Would like an idea of something a little more solid than the certified flange mount. Thought about going through the leading edge also. Dunno. Also, are most going with the pitot/static out on the wing or are you monting a static port on the fuse? Ideas appreciated - then I can get some sleep.
Thanks, Jay

Bugs66
09-27-2005, 09:14 PM
I am leaning towards doing a Cessna style. I keep going back and forth. I do know I want to install a Dynon and would like the AOA functionality. Their pitot has a built-in AOA port. So chances are I'll do that.

See: http://www.safeair1.com/ and click on the "pitot mast" and "Dynon".

Here is an example how Legend Aircraft mounted on their Cub. I wish I had a closeup.
http://www.legendaircraftcompany.com/upload/FloatCub126_112.jpg

T.J.
09-27-2005, 09:39 PM
delete

AkPA/18
09-27-2005, 09:59 PM
TJ

No difference with the window shut ---but if you open the side window and put pressure into the cabin you can sometimes have up to a 5 mi diff in cruise---slower with the window open. By the same token I have flown with a low pressure with the window open due to a configuration and then I would indicate up to 5mph faster.

Mark

Bugs66
09-27-2005, 10:04 PM
Mark,
Do you have any suggestions on where to put a static port if doing a Cessna style pitot? I wonder where Legend put their static port?

Steve Pierce
09-27-2005, 10:33 PM
Probably on the pitot tube. Usually those type pitot tubes have a static port on the sides. Played with static ports on boot cowls and in the tail. Can be very tricky and aggravating.

AkPA/18
09-27-2005, 11:49 PM
Bugs

No suggestions because I just don't know enough about locations. I always ran mine off the back of the instrument inside the cabin like TJ says---less to freeze up. That is why I am familiar on what can happen running them that way. I do know where the cessna style static port is located on the CC cub but I do not know if they are running an alternate interior static air source like cessna. See if this link works---it shows a static port located on the filler strip between the boot cowl and the fabric midway between the trim striping.
http://www.cubcrafters.com/cci/images/ranger4_lg.jpg One on the other side-----same location.

Mark

Bugs66
09-28-2005, 02:22 AM
Thanks Mark. I see the location on the CC cub. Interesting. Did you try that area Steve? Still want to know where Legend put theirs.

Pat Bowers
09-28-2005, 07:36 PM
Legend uses cabin pressure for static. we've done a few and it works fine. WE ARE CURRENTLY INSTALLING ONE SO i'LL TRY TO REMEMBER TO TAKE SOME PICS AND POST THEM. iNCIDENTLY, THE NEW LARGER SIZE DYNON EFIS IS THE GREATEST. WE OLDER GENTS CAN SEE IT WITHOUT GLASSES. ANYONE GOING TO COPPERSTATE FLY-IN CAN SEE ONE FIRST HAND IN A CUSTOMERS LEGEND. PAT at LEGEND

Bugs66
09-29-2005, 12:14 AM
Legend uses cabin pressure for static. we've done a few and it works fine. WE ARE CURRENTLY INSTALLING ONE SO i'LL TRY TO REMEMBER TO TAKE SOME PICS AND POST THEM. iNCIDENTLY, THE NEW LARGER SIZE DYNON EFIS IS THE GREATEST. WE OLDER GENTS CAN SEE IT WITHOUT GLASSES. ANYONE GOING TO COPPERSTATE FLY-IN CAN SEE ONE FIRST HAND IN A CUSTOMERS LEGEND. PAT at LEGEND

Thank you for this information Pat. I am looking forward to some closeup pictures. So with the cabin static do you not see a difference in readings when the door/window is opened or closed?

Steve Pierce
09-29-2005, 06:46 AM
You do but it's a Cub. Played with this when we rebuilt my Dad's Clipper. He was annal about getting the airspeed acurate. I have seen it on the boot cowl, cabin etc. Never worked well. You need an undsturbed area. Finally copied the late model Tri-Pacer and put it on the bottom of the tail and it worked great. Jim Richmond had a static vent on the SC they were getting certified for the 2300 lb gross weight at OSH the year before last. I imagine to meet the requirements of part 23 they have to have a static system. I would checkout one of their new planes.

tempdoug
09-29-2005, 09:01 AM
Pipers pitot tube mounting bracket is part # 11580-00. why couldnt you use this bracket that they used. mount it in front of the rear spar on the inner end of the aileron like they did, bend a tube 90degrees and weld a little flange to the tube so things are sitting like there suppose to and fasten it to the piper bracket. why add a pound or more when you dont need to. could probably add a little flipper on there also so when its on the ground bugs dont crawl up it looking for a new home. doug

tempdoug
09-29-2005, 09:11 AM
if your experimental the bracket could be made a little stronger to avoid the cracking. doug

Bugs66
09-29-2005, 11:33 AM
Pipers pitot tube mounting bracket is part # 11580-00. why couldnt you use this bracket that they used....

I think the main argument against is having another probe hanging down in addition to the Cessna style pitot.

Steve, which part of the tail exactly? According to Mark's photo, CC has a static port just behind the boot cowl on the fairing.

JayH
09-29-2005, 12:09 PM
Great discussion!
Bugs: If you go with the air saf pitot mast, which skin will you use to mount to or do you plan to install some additional skin off the spar to accomidate the front rivet points?
Doug: Also good point. The bracket inside the wing that attaches to the spar is no problem. THe cracking that I've seen is on the round flange that is welded to the tubes with the screw holes in it. You are right, I could beef that flange up a bunch and probably cure that problem.

Reference Static: I would be interested also in the port locations, I'll stay tuned for pics.
P.S. The wings I'm working on are Smith wings.
Thanks for all the input.
J

JayH
09-29-2005, 12:11 PM
Bugs,
Safeair - it was in my head, just came out wrong.

Bugs66
09-29-2005, 12:12 PM
...
Bugs: If you go with the air saf pitot mast, which skin will you use to mount to or do you plan to install some additional skin off the spar to accomidate the front rivet points?...

I think I will install my mast pretty much the same where Legend does. I will add whatever flanges/bracket I need to mount the Safe Air mast.

JayH
09-29-2005, 12:21 PM
Bugs,
Sounds good. I like the looks of this pitot mast and will definitely keep this as a option.
Thanks again

tempdoug
10-02-2005, 06:50 PM
i was wondering and ive never looked but on a j3,pa11, pa18-90 do these just use cabin pressure for static pressure? doug

T.J.
10-02-2005, 09:15 PM
Yep:
The pitot tube is a copper tube sticking out of the middle of the front jury strut.

tempdoug
10-02-2005, 09:41 PM
what do they use for the static port though? they must not have anything at all on the back of the airspeed. doug

T.J.
10-02-2005, 09:57 PM
Yep, thats correct. Somehow, they seemed to work ok. Wonder why?

Dan2+2
10-03-2005, 09:58 AM
Both the J4 and J5 I fly have two copper tubes in the center of the jury strut one pitot and one static. The pitot is flared and the static is sealed on the end with four small holes on each side of the tube. But I don't see any big differance with the static unhooked at the back of the airspeed. I don't really think they are correct either way!