Thorp Air Command - T18.net

Hello all!

I have been a lurker for quite a while, and finally was forced to join the forum by a recent purchase of a T-18!

I recently picked up the flying project that I now proudly call my own. For those of you who have seen her, I am talking about N33TB.

The bird needs a lot of help. She has been neglected and beat up for many years. The panel is bad, the back of the panel is even worse.

Things I have already had to do:
> Remove an LC filter circuit attached to a DC jack that was shorted out and getting so hot it was burning knees.
> Remove a Loran unit and repurpose it as a bookend, which is basically all they are useful for now.
> Flip the electric trim switch over so that it makes sense. (Don't try to tell me that pushing the trim switch up should raise the nose......)

Things that need to be done
>ENTIRE back of the panel rewired. It is not just ugly, but purely unsafe. Things are grounded where they shouldn't be, wires wrapped around screws instead of ring terminals, etc....
>Fix the broken vacuum system or rip it out. The AI, DG and suction gauge are all crazy. I was told that the vacuum pump was replaced, and I have this sneaking suspicion that it was replaced with a pump that rotates the wrong direction. That or the regulator is bad or needs adjusted (they dont usually fail) or all the instruments are bad. This last one is not likely the cause, but could be the effect of one of the other problems burning out the bearings. I am half tempted to just rip them all out and throw a Dynon D10A in there and be done. I might save some weight too.
>New aileron hinge pins with holes drilled in the pin for the safety wire or cotter pin to go through. The pins are not currently held by anything but magic and luck.
>Modify the cowl to allow the oil to be checked without being a 15 minute ordeal.
>Make the carb heat actually heat the carb.
>Modify the seats and bottom of the panel to make my knees fit.
>Install limit switches on the trim system so the motor doesn't drive against the stops
>The other 5000 things that need to be done.


In the initial test flights, I have two impressions:
1) Hot damn, this is a rocket ship. I love this airplane.
2) Holy crap, this is a b***** to land.

The first one is expected, but this second one threw me. I was expecting much nicer landings, especially considering the very friendly taxi characteristics. She is a pussy cat on the taxiway, but a bit of a tiger on landing rollout. I brought a CFI along who has gobs of tailwheel time, and his comment was that "she lands like a flying saucer." I tend to think we are both missing something. Every time we land she wants to go flying again. Wheel landings with a bit of forward stick to pin her down are okay, but she is super squirrly until we can get the tailwheel down. 3 point landings no matter how soft, seem to result in at least one skip followed by some tailwheel clamor as she settles in.

We have been landing full flap (this bird IS limited to 30), so tomorrow I am going to go experiment with some different landing configurations. Also, this is an o-360, so the extra weight out front might not be helping. There also could be something wrong with the rigging or gear. I really don't think she should be QUITE this much of a handful.

Anyway, for now I am in love. 170mph at 9gph all the way home, and that was into a headwind with a climb prop at 2400rpm and 20" mp. With the aileron spades on this plane the stick is one of the lightest I have ever flown. The maneuverability is fantastic.

I know at this point with this plane it will be flying for 1 hour and working on her for 4. I'm fine with that. I hope to someday restore her to my own perfectionist standards.

For now, greetings to all, and thank you for all the amazing info you all provided when I was looking at buying into the community. I didn't even have to ask and all my questions were answered.

Cheers,
-Ian Ahner
N33TB 180hp T-18

Welcome Ian! Congrats on your purchase. I would suggest aligning the gear. They need to be straight or slightly out with weight in the seats. It really helps tons..
Enjoy.
Cubes

My aircraft was a bit squirrly on landing in the 60-40 mph range. I adjusted the toe-in to nuetral and it tamed the handling problem. I would check the toe-in of the main gear and adjust as needed.

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

Hi Ian
I can't tell from the photos, but if TB has the original tail spring- consider replacing it with the trusty tail rod and aviation products tail wheel. By doing so you'll lower the tail an inch and be able to get closer to a full stall landing. That will unload the wing and get a shorter transition time between lift and no lift.
Enjoy making TB yours.
Terry

Hi Ian,

Congratulations.

Been there, done that, bought the t-shirts, tools, radios, parts, materials, books, GPS, repairs, hardware....the list goes on. You're lucky to have the option to fix and fly at the same time.

It is unfortunate that there are so many examples of neglect in the fleet. Old airplanes tend to stay that way. THe good ones are owned by the folks who are active on this forum. We can only hope that pride of ownership trickles down.

Feel free to contact me offline. I've made every mistake in the book. I might be able to save you time and money.

DW
(edwolff)(at)(bmts)(dot)(com)

Awesome Ian - as has been said, check the wheel alignment. A carpenters bubble level with a laser is helpful with this. Just put it up against the wheel and mark where the laser points on the back wall of the hangar and measure the distance between the marks. Obviously, make sure the plane is square to the back wall. If the distance between the laser dots is greater than the distance between the wheels, you have toe-in. If you can extend the aircraft centerline to the wall, you can also see if one wheel is more cockeyed than another. The other thing to check is the tailwheel. Take the tail off, inspect and make sure that the connections are solid and the assembly is as per plan or better. I made a few landings in a T-18 with a tailwheel held on only by the bottom skin. They were unnecessarily fun landings. There have been other instances of these conditions on T-18s. Somewhere on this forum are pictures of the repair I made.

Keep practicing. I found that concentrating on precise airspeed control on final improved my landings markedly. Having said that, make sure you know the "indicated" stall speed from a safe altitude. There are inaccurate ASIs out there causing pilots to motor down final at 15 knots too fast and crow hop down the runway to the delight of onlookers. Having having said said that that, don't get too slow either.....precise airspeed control, good alignment of the mains and a solid tailwheel will get you the polite applause and the oohs and ahs of the cheap seats more often than not.

Cheers

_________________
Fraser MacPhee
N926WM
Serial #279-1
Angel Fire, NM (KAXX)

Welcome to the club. another machine getting the attention it deserves.

_________________
http://www.dixiefriedfabrication.com/

Wow. Four hours in her today. Most of that was landings. Some things I've noticed:

1) I was coming in a bit fast. I had been flying the approaches at 90 and bringing her back to 85 over the fence. This was part of the tendency to go flying again, I think. Slowing back to 80 over the fence and bleeding it off before touchdown helps a ton. On the flip side though, if you get too slow, she falls out hard. Ask me how I figured that out.

2) She really REALLY hates crosswinds. I decided to go over to the other runway and practice some crosswind stuff. I ran out of controls very quickly and got pushed across the runway pretty far. I resorted to landing on the upwind side of the runway just expecting to get pushed over to the centerline before I get slowed down.

3) The only thing this bird hates more than crosswinds are stalls. She was NOT having it. I pulled back the power slowly and just maintained altitude as she slowed down. At about 60mph things got a little wishy-washy. At 55 she threw a temper tantrum. It felt almost more like a wash-out than a stall. She shook and shuddered and tried really hard to drop a wing. No preference on which wing, but holding her in that required various rudder-to-the-stops inputs to keep the wings level. In this we were able to get some falling-leaf type results, but she shuddered the whole time and definitely didn't like it.

I will check the gear alignment, that may be a good lead. I will also take some pictures of the tailwheel and post them.

For those of you here, what speeds do you like to approach at? I have been preferring 3-pointers. Does anyone here prefer to wheel land these? What does that look like?

Loving the bird, but there is a learning curve for sure.

Cheers guys!
-Ian

75-80 over the numbers, 1 notch flaps, I hold it off till it stalls on 3points, yank the stick back the tail sticks, yank the stick back too soon when you are a little faster and it gets airborn again. Congrats on your purchase!! Dan

1) I was coming in a bit fast. I had been flying the approaches at 90 and bringing her back to 85 over the fence. This was part of the tendency to go flying again, I think. Slowing back to 80 over the fence and bleeding it off before touchdown helps a ton. On the flip side though, if you get too slow, she falls out hard. Ask me how I figured that out.

Even Cessna 150 fall hard at some point. The old Land-O-Matic softened the blow, a luxury not found on a T-18. Sounds like your are getting more comfy with the speeds though.

2) She really REALLY hates crosswinds. I decided to go over to the other runway and practice some crosswind stuff. I ran out of controls very quickly and got pushed across the runway pretty far. I resorted to landing on the upwind side of the runway just expecting to get pushed over to the centerline before I get slowed down.

X-winds can be tricky....lots of wing down. The cranked wing helps with this I think. I have landed in about a 20 knot direct X-wind (low on gas) Not fun, but doable. I took the opposite of you and landed on the downwind side of the runway pointed more into the wind. Obviously, the wider the runway, the better.

3) The only thing this bird hates more than crosswinds are stalls. She was NOT having it. I pulled back the power slowly and just maintained altitude as she slowed down. At about 60mph things got a little wishy-washy. At 55 she threw a temper tantrum. It felt almost more like a wash-out than a stall. She shook and shuddered and tried really hard to drop a wing. No preference on which wing, but holding her in that required various rudder-to-the-stops inputs to keep the wings level. In this we were able to get some falling-leaf type results, but she shuddered the whole time and definitely didn't like it.

LOL....sounds more like your bird was doing exactly as you made her do......It's nice to hear of people keeping up with good rudder skills....keep up the good flying.

_________________
Fraser MacPhee
N926WM
Serial #279-1
Angel Fire, NM (KAXX)

I wheel land mine, especially in crosswinds. Much more controllable. The tail better be down by 40 tho, or you will lose rudder effectiveness. I come over the fence at 70knots.
Cubes

I stabilize my approach at about 82 mph and chop the power when over the numbers. I tend to 3 point it regardless of the winds. I have found my plane to handle cross winds just fine. Somethimes I touch and roll a bit on one wheel but it is perfectly controlable. The toe-in in critical that it is set at zero degrees.( I use the string and square method to check mine) I also added VG's just ahead of the rudder and now it thinks it is 6" taller and as a result there is no more dancing on the pedals when the tail is down on roll out. I also have the Trusty tail spring with the Aviation products tail fork assembly with a solid 6" Matco wheel. The Matco wheel is much lighter than the cast iron wheel with the Aviation Products assembly.

Regards,
Jim

Jim, how about a pic of the VGs on the vert stab? I'm interested

Here is a picture of the VG's. They are from a company in Australia.

I hope this posting of the picture works.

Jim

Darn,

It might look right for the guys in Austalia or you can flip your screen to see the right orientation.

Jim