PFH Sonex B

[Bryan Cotton]

I used a bandsaw and holesaws.

[pfhoeycfi]

Update...
End of year is near. Began in Feb, built 5 tables, 1 wingstand and have completed the tail surfaces, both wings (w 1 duckworks lndg lt & Orion 600s on the tips) and just finished up on the right flap today. I've been polishing as I go but might wrap in the end. Hope to finish the other flap and ailerons soon and will jump into the fuselage early next year. Will need to start considering engine and instruments. I would love to build the aerovee but leaning toward the jab.

Lessons learned...handle the leading edges carefully!!! Talk with somebody that has before attempting to remove them from the shipping box. And consider carefully using aluminum rivets (ie at the tips). Stainless rivets are far easier to drill out. Regarding tools...just by em all...

Peter H
SNB0021

[pfhoeycfi]

First flight today. Left rolling tendency. Some shimmy on landing. Power limited by CHT. Any recommendations on the left roll tendency?
Peter

20221218_070052.jpg (214.97 KiB) Viewed 3338 times

[Bryan Cotton]

Congratulations Peter! That is awesome.
I am still working through left rolling tendency. I have center controls so I can switch back and forth. Objectionable forces in the left seat, and perfect in the right seat on my early flying. I've been adjusting the left flap down, as the right flap was up tight. So far I had 1 turn down on the ball joint, and after the last flight I added two more turns. I verified thread engagement. Before I had been going 1/2 turn at a time and currently I have a very slight right roll in the right seat and and noticeably more left roll in the left seat. When I fly today I'll see if 2 turns is too much, not enough, or just right. I have not noticed any performance difference with the adjustments so far.

Shimmy on landing - yep. I'm getting better at avoiding it. Here are my three techniques:
1) For a full stall landing, plant the tailwheel first and do a real stick back full stall drop on the mains. This gets the speed slow and I think more importantly gets weight on the mains. Works best on grass because it's really hard to see over the nose to keep it straight and grass is more forgiving. But, I do it on hardtop too and I'm getting better at judging it.
2) Wheel landings - go from a gentle touchdown to a level attitude with a confident application of forward stick. You see better to keep it straight. Once the main gear is loaded with the weight of the aircraft, it tends not to shimmy.
3) Brakes - I still get a little shimmy, sometimes on the transition to nose high or in the aftermath of a full stall landing on hardtop. Once I am settled and stable, a little application of brakes generally shuts down the shimmy.

Oddly, I've never had high CHTs. Not sure if my TCs are bad or if I've just done an awesome job with my baffling. I really did go pretty nuts on the baffling.

Your Sonex B looks great!

[T41pilot]

I had a quite heavy left wing on my first flight. You can dial that out by drooping a flap a half turn at a time on the linkage. I ended up using a small trim tab on my right aileron that can be removed if necessary with passenger on board and putting my flaps back to neutral. I have 6 flights and still have high cht unless I pull the power back as soon as possible. Hope that breaks in better down the road.

[pfhoeycfi]

Thanks i will try those recommendations. My other issue was airspeed. Along with the MGL MX1 for airspeed, I have the MGL ASV1 as a backup, both piped to the same pitot tube. They have a 15 mph difference between them, the MX1 higher than the ASV1. The altitudes are reading very close though. I'll have to figure this out as well..
Peter

20221218_085132.jpg (83.76 KiB) Viewed 3297 times

[pfhoeycfi]

Made my third flight today, this time for only 20 minutes before work. I had removed my wheel pants and fairings...and did not experience any wheel shimmy on this flight. Not sure what to make of that. The left roll tendency is only slight now after having made some adjustments. I will try JM's drinking straw test next. I still can't get the MGL MX1 to write flight data to the SD card.

[Bryan Cotton]

We don't get much shimmy, except when light on the wheels in the 3 point attitude. Removing wheel pants will increase the natural frequency a bit. Also it took me a while to get the sight picture. That helped. I find that when my son is off on directional control we sometimes get some shimmy. Good to hear you are flying.

[daleandee]

1) For a full stall landing, plant the tailwheel first and do a real stick back full stall drop on the mains. This gets the speed slow and I think more importantly gets weight on the mains. Works best on grass because it's really hard to see over the nose to keep it straight and grass is more forgiving. But, I do it on hardtop too and I'm getting better at judging it.

Just a heads up on using the term "full stall landing" as I got slammed pretty good some years ago by Joe Norris for using that term. I'm certain he would be nicer to you though! 8~)

viewtopic.php?f=3&t=3376&p=25588&hilit=full+stall+landing#p25588

[Bryan Cotton]

Just a heads up on using the term "full stall landing" as I got slammed pretty good some years ago by Joe Norris for using that term. I'm certain he would be nicer to you though! 8~)

viewtopic.php?f=3&t=3376&p=25588&hilit=full+stall+landing#p25588

Thanks Dale! I've been avoiding the 3 point. The shimmy demon lives there. If I plant the tailwheel and drop it onto the mains, I don't have that issue. Wheel landings are good too, but I haven't started teaching them to my kid yet.