Tailwheel Shimmy and Spring Arch

[jeremygerhold]

Ok fellas here's my update looked at my logbooks looks like they replaced the tailwheel spring 3 years ago with a new univair one. So what I did was bend it down 1 1/2" down and went and flew the pacer. The plane did great no shimmy.

 

[PACERGUY]

Excelent!! I was able to flatten a 3 leaf and 4 leaf tail spring both in only 1 year. Sometimes tail first is the right thing to do. Look up the MAF landing with Bill White. It is big with the Cessna guys but will work for a tailwheel low landing in a Pacer. DENNY

 

[akflyer]

Excelent!! I was able to flatten a 3 leaf and 4 leaf tail spring both in only 1 year. Sometimes tail first is the right thing to do. Look up the MAF landing with Bill White. It is big with the Cessna guys but will work for a tailwheel low landing in a Pacer. DENNY

T3 is a game changer. No more flat tail springs.

 

[PACERGUY]

The T3 and ACME tail shock are both great for helping protect the air frame with tail first landings but to get correct head angle they increase the tail height. This in turn will effect rotation and increase takeoff distance. Same issue with a Baby Bushwheel vs stock tailwheel great for landing/sand/tundra but effects AOA on takeoff. Just have to look at all the Pros and Cons then pick what will work for your type of flying. DENNY

 

[akflyer]

The T3 and ACME tail shock are both great for helping protect the air frame with tail first landings but to get correct head angle they increase the tail height. This in turn will effect rotation and increase takeoff distance. Same issue with a Baby Bushwheel vs stock tailwheel great for landing/sand/tundra but effects AOA on takeoff. Just have to look at all the Pros and Cons then pick what will work for your type of flying. DENNY

31s go a long ways in helping with that. Unless you are flying off pavement or grass, 3 point take offs will make longer take off runs. No way in sand or gravel do you want the tail wheel on the ground as its just an anchor. If your technique is poor enough to be banging the TW on the ground when you rotate then the T3 or Acme will again save the plane and not loose the arch. Start the TO roll with 1 notch flaps and full down elevator, as the tail comes up relax the down then pull 2nd notch at 45 and pull back. TW never touches the ground after the first 50' of the run (solo) its a bit longer at gross. I watch a lot of guys being really inconsistent trying to mimic the valdez style bang the tail bs.

 

[Steve Pierce]

I see Dan is in the process of obtaining an STC for his T3.

 

[Peter Pacer]

I’ve been looking. It seems I can’t find the template that you’re speaking of. Can you help? Thank you

A shimmy can tear up the tailwheel pretty quick. When we were fighting ours we had to replace the thrustplate assy a couple of times when rebuilding. Got to the point I bought extras knowing the pins would be broken when I took it apart. Also seemed to wear the tire out pretty fast. Since we got the arch reset (using the template) and the shimmy taken care of all I've done is disassemble/relube/reassemble at each annual. The whole process is really pretty quick. We do replace the mounting bolts since they take a fair amount of abuse.

I’ve been looking. It seems I can’t find the template that you’re speaking of. Can you help? Thank you

 

[Steve Pierce]

https://www.shortwingpipers.org/forum/showthread.php?7715-Tail-Spring-Arch-Template

 

[Peter Pacer]

Thank you!!

 

[iRideKTM]

I recently replaced the dreaded Univar tail spring with the ABI tailspring and have a few questions. The first is torque, is everyone using table 7-1 outta 43-13 for torquing down the mount bolts? I don't have a problem torquing the tailwheel side since it's all solid metal but I am nervous about doing the airframe side bolt since I assume it goes through a tube and I dont want to collapse the tube so what torque should I set for both bolts? The other question is more of a request, can anyone supply me with verbiage for a logbook entry? A hangar neighbor is an IA as a hobby so he's only done a couple owner-produced entries. He said if I bring an entry that's been used with the ABI spring, he'd have no issue signing it off.

 

[smcnutt]

"Replaced the crappy Univair spring with one that actually works...." well, maybe wait for someone more FAA eloquent than I. :lol:

 

[Steve Pierce]

I recently replaced the dreaded Univar tail spring with the ABI tailspring and have a few questions. The first is torque, is everyone using table 7-1 outta 43-13 for torquing down the mount bolts? I don't have a problem torquing the tailwheel side since it's all solid metal but I am nervous about doing the airframe side bolt since I assume it goes through a tube and I dont want to collapse the tube so what torque should I set for both bolts? The other question is more of a request, can anyone supply me with verbiage for a logbook entry? A hangar neighbor is an IA as a hobby so he's only done a couple owner-produced entries. He said if I bring an entry that's been used with the ABI spring, he'd have no issue signing it off.

I just make it tight. The mount is hollow so I use a grade 8 washer on both ends. I also bush this mount at recover.

 

[RRHall]

I just received the ABI tailspring and have a slight issue. On the tailwheel the new spring is wider than the Univair spring. My tailwheel has an insert and what looks like a bushing. I can't get them out to fit the new spring. I would think it just lift or tap out but I can't seem to get it to move.

 

[moto657]

I just received the ABI tailspring and have a slight issue. On the tailwheel the new spring is wider than the Univair spring. My tailwheel has an insert and what looks like a bushing. I can't get them out to fit the new spring. I would think it just lift or tap out but I can't seem to get it to move.

View attachment 23068

Looks like there’s a dowel pressed through the tailwheel head and the spring insert. You probably need to tap that out to get the spring insert free

 

[Steve Pierce]

I knock the bushing out with a bushing driver. Then I cut that bushing down to fit the head less the spacer.

 

[Jim Hann]

I knock the bushing out with a bushing driver. Then I cut that bushing down to fit the head less the spacer.

I/we did the same on my 3200.

 

[Brian]

Applying some penetrant oil followed by heat will help. The aluminum will expand more than the steel bushing with temperature rise. Looks like the bushing may have already been hammered on too so it may move in one direction easier than the other.