Patrol tailwheel rod spring hole alignment

[podo]

New kid here. Finally made the first move on my Patrol QB kit which was to get the fuse on its feet, starting with the tailwheel. The builder manual reports AN4 bolts front and rear and the rod spring is drilled as such, but the rod socket from the factory has a 5/16" hole as is shown in Bob's drawing. If you put an AN4 bolt through the spring and snug it up without recognizing that the socket hole is oversize, you'd find out when the first side load hits the tailwheel and it winds up canted several degrees. Also, the holes in the socket are a wee out of alignment. I made bushings and used a round file to coax the holes square.

[noema]

I just installed mine the other day. There should be a manual with the tailwheel. Besides installation instruction it also has a lot of useful maintenance information. It says to match drill the rod and use an AN5 bolt at the fuselage side. My two holes were perfectly concentric so I simply drill the rod out on a drill press.

• Loctite 620, for possible play in rod socket
• rod to fuselage
  • 1x AN5-15A bolt
  • 2x AN960-516 washer
  • 1x AN365-524 nut
• rod to tailwheel
  • 2x AN4-14A bolt
  • 4x AN960-516 washer
  • 2x AN365-524 nut

[podo]

Thank you so much, Stefan. I found the instructions underneath my copy of Modern Moron magazine.

[spinningwrench]

The pilot hole in my fuselage was drilled a bit off as well. Since a drill bit would just tend to follow this hole I built a jig with removable drill bushings and enlarged the hole to a AN5 with the final pass being done with a reamer for a snug fit on the bolt.

TailPost Stinger Drill.jpg

[Jim Herd]

New member here - Jim Herd, KMEV, near Lake Tahoe. Proud new owner of N185BP. It is Patrol kit #5 - delivered in 2012 and first flown in 2017. Only 80 house TT. The builder did an excellent job. I have been reading a lot of then posts here, and I know enough to be dangerous. I have 2500 hours in my self-launch motor-glider (DG800B) with a steerable tailwheel, and 2000 hours in my Bonanza. Still training in the BHP, with 5 hours and 30 landings so far. I think I have the same problem noted above. Symptoms: tailwheel leans to one side, I get shimmy on landing, and taxiing is very heavy on the right rudder and very light on the left rudder. See photos. Any advice is most welcome.

[Nev]

Welcome to the forum Jim. I had a similar issue but on a BH4. It was easily fixed. I'm sure Mark Goldberg will chime in, you'll find he is excellent in answering questions and support.

Having the tail wheel off center like that could pose a challenge to landing so might be good to get it sorted before proceeding. You might notice recent discussions here about us guys with low tailwheel time being more prone to having a few mishaps (LODCOG) so please take it carefully.

Tailwheel shimmy is often related to the angle of the king-pin and can be amplified when holding the elevator full aft. I found mine went away completely when I learned to keep the tailwheel just off the ground until slowed.

[David Swartzendruber]

I had the same issue when I went to mount the tailwheel on my LSA. In my case, the holes in the tailwheel socket weren't at quite the right angle. I upsized the hole at the front of the spring from 1/4" to 5/16" and changed the angle of the new hole to correct for the tailwheel misalignment. I did this on a milling machine with a carbide endmill. You can see a bit of a write-up about in on my eaabuilderslog entry. https://eaabuilderslog.org/?blprojen...&listcat=&sid=

[Bcone1381]

Boy, that was a long time ago when I also dealt with this issue. I know Bob was involved with the fix. Seems to His fixes are always quick, easy, and right.