Thorp Air Command - T18.net

I would like to be able to park my T-18 under my Cessna to free up some space but the tail mounted pitot tube sticks up too far to get it under the wing. Has anyone changed the pitot tube location on an existing aircraft? Is it a feasible mod to a completed aircraft?
thanks

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

I would think its feasible. My pitot is in the wings gap between the outer wing and inner wing. I wouldn't think it would be that much harder to route tubing through the outer wing if you wanted the pitot out on the wing tip.

Seems to me that someone in the old days made a removable tail mounted pitot static tube. They removed it for hangar storage as you note.

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Bob Highley
N711SH
SN 835
KLAL

My aircraft had the pitot/static on the vertical stab, the static is now on the sides of the fuselage and the pitot is mounted at the left wing tip. The old pitot/static tubes were cut flush with the top of the stab, the old tubing was left in place in the aft fuselage.

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Bruce Finney
N18JF T-18C #262
Yelm, WA USA

John Kerr just shortened his .

RB
El Chapo

Thanks for the replies. I will add it to the list of mods to be completed after I finish the upgrade I started in Nov that was only going to take a day.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

Since you raised the subject, my static ports are on the side, per old newsletter. Pitot is 1/4" OD on the left wingtip about 6" down and 3" ahead of the spar. I've always wondered if the diameter makes a difference. Anybody know? If I remember P=1/2 density*V^2, no mention of diameter.

Les

Diameter seems to be determined by what size bug you want to crawl up in there.

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Bob Highley
N711SH
SN 835
KLAL

I'm changing mine as well. It's on the vertical stab and poorly accurate unless I'm in level cruise. On take off the slip stream causes it to bounce all around. When practicing stalls the indicator slows down to about 60mph then jumps back up to 90mph (while my ground speed continues to drop on the stratus) then it stays around 75ish as the wing buffets. I didn't really pay attention to the indicator until today when I was actually testing it at high altitude. Mine has quite a bit of warning before hand so I just use that when in the flare.

I'll be doing wing tip so I can also use AOA with a dynon 10a (or something similar which I haven't decided on yet).

I have a PA 28 knife pitot/static mounted on LH wing. Positioned proportionally in the same place as on PA 28 Hershey bar wing. Has worked great for 27 years!

Tony
ZK - VMS
T18c

Tony, do you have pics on how you mounted it? The blade on my vertical fin is exactly the same as my Cherokee and it would make my life much easer if I could just move that blade to the wing.

Jeffj, have you moved yours? If I couldn't find a way to mount my blade I was going to use 1/4" tubing like others have for an under wing pitot. Then I would have to get a static port since my static is in the blade I would remove.

No, I haven’t moved it yet. Too many other irons in the fire and I cannot get the tail under the Cessna even if I had made the change until I have a place to go with the Pawnee wings. Signing off the condition inspection now. If it will still fly, I think next up on the Thorp list is a baggage compartment. Then probably finish brake mods and find some wheel pants for it.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

Jeff, will have to go to hangar and take a pic. I have the folding wing and the blade is in the outer panel. This necessitates having quick disconnect fittings to enable wing removal. Have nice self sealing fittings ex A4K aft fuselage split.
Tony S
ZK-VMS
T18C

Ok, well next time you are out there and remember snap some pics if you can and let me know. I think I'll just have to fab up a mount to rivet to the wing rib internally in order to have a flat place to mount it. Thanks!


Jeffj, when you start looking for those wheel pants let me know. I'd like some better ones than the original open side ones so I can edge out as much speed as possible on this small engine but I don't really have time to spend 30+ hours making them nor do I have the skill. 1500$ for a set is a little salty as well for what I'll have in return otherwise I'd try to modify the rv series for my wheels.

I don’t think you would want my wheel pants. I have been flying without them for a year because I figured out they were costing me 5 mph. They were fitted level with tail on the ground which gives them a serious nose down attitude in flight. They appear to be the MF-4 wheel pants Aircraft Spruce is selling for $228.95 minus the mounting hardware.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson