rudder trim ?

[triumphantduke]

I’ve been kanoodling a concept that would be retrofittable - a linear actuator that can be mounted either fore or aft of the pedal assembly and on each cable attach point - you could either wire it with an on/off as well as a push pull button (push left, pull right side - or vice versa) OR keep the control simple and just have a on off. That way you press right rudder, switch power on for the holding torque, power off removes holding torque. The second sounds easier to not forget if when brains get saturated - I’ll come up with a ready to install plan, but won’t do so until after flight testing and I feel that for myself rudder trim would be desired.
lots of theory and a few unknowns,
-what would the off resistance be to the pedals?
-w/ a simple on off, maybe just set holding power to a single actuator for the rudder pedal that is desired(less to overpower?)
-what is the overpower scenario, can I forget to turn off the holding torque but still over power holding torque without damage in order to control the aircraft
-what is the least amount of holding torque needed? What kind of upper limit? (No idea b/c I’m not flying yet, this drives the concept to be retrofit-able)

I’m hesitant to participate in discussions, b/c I’m not flying….yet. That doesn’t invalidate an idea or opinion but should be made crystal clear on every post (your user status can change over time) for those reading to be aware and appropriately cautious. The culture should allow discussion, so long as your disclaimer is visible so we don’t have a blind leading the blind situation.

[jaredyates]

It sounds a lot like the Ray Allen trim servo in function. A single one of those on one side's spring seems pretty simple. I don't think you'd need input on both the left and right sides? If you had an actuator on both sides, you could introduce the threat of tightening or loosening system tension.

[triumphantduke]

Yes that would not be a happy situation over time - now you’ve got me thinking about a 3 position switch to keep user error out “Left Hold - OFF - Right Hold”

I’m having trouble imagining one actuator working for both left and right rudder - pressing the left rudder but then holding torque on only right pedal, would allow air pressure to push the left pedal back?

[triumphantduke]

Similar to that but specked/sized specifically for the application- as an example…. Never heard of this company or reputation, so just to get the juices flowing https://www.easye.us/pdf/easyE_35.pdf

The duty cycle for this one is iffy or unclear on time vs load


how much “joggling” of the rudder pedals is done in “cruise” - in your experience(and anyone else who wants to participate in this survey) would that invalidate this rudder pedal cruise hold idea? Or maybe I’m thinking about the rudder trim idea all wrong, if it’s typically associated with an adjustment of “neutral” or control force adjustment while still joggling the pedals as needed in cruise

[schu]

One thing not mentioned in this discussion is the difference between airplanes and how they each fly. All Bearhawks do not fly identically because they are experimentals built by different individuals with different abilities or determination to properly rig their planes. Also added to the mix are plans built plans versus the kit built planes. Just quite a bit of room for variation in how they all are built and how they fly. All might be Bearhawks, but my observation is there are often differences in how they fly and the "stability" each one demonstrates. Mark

I agree, and it's unfortunate. Is there a definitive source for rigging, troubleshooting flying issues, and tests to confirm that the airplane is acting correctly?

I consider myself well versed in the bearhawk world, but I can't think of any definitive source, so my plan was to read through all of KevinD's posts and get really meticulous before I fly. The last thing I need on a maiden flight is poor handling airplane that could have been completely avoided if I was just picky about rigging.

[jaredyates]

Kevin wrote some nice Beartracks articles, let me know if you don't have them and I'll send a pdf.

[Bissetg]

I’m aware of two Bearhawk 4s (IO 360 and IO 540) that had rudder trim issues, turned out the fabric tape on the trailing edge of the rudder had detached along a length of about 4 inches and would create drag simulating a trim tab but when you looked at it on the ground with no significant airflow you couldn’t tell the tape wasn’t secured in place.

I always run my fingers on my trailing edge tapes as part of my preflight now.

My aircraft doesn’t need rudder trim for my ops but I don’t know about a 540 powered one. With all that extra boogie it might.

[500AGL]

Just because this thread has gotten so exciting (!!) I'll add my personal opinion as well. I know, just what you want to hear. hahahaha... sorry, not sorry.

Perception and Point of View are always words to consider when talking about what an aircraft is used for, and perhaps what it was designed for. How well it works in each area is by and large the perception of the owner or pilot.

I've owned two cubs. Light, great, bounce around your region aircraft for open door flying all summer long, and when bundled up absolutely a blast on skis in the winter.
Compared to those, the Bearhawk Patrol has the stability and ride comfort of a Beechcraft Bonanza. The Bearhawk's aluminum wing and sq ft wing loading contribute heavily to this, but FOR ME, quite literally I will jump in it at a moments notice and go to anywhere in the country, because it's just that nice. So yes, from my Point of View, it's freaking awesome. Only thing better (for me) doing a very similar job is the Model 5.

I give rides all the time to airline pilots, Baron/310/Navajo owners and more, and from their point of view, the Patrol can be another bounce-around-the-neighborhood airplane. Their idea of XC is at 13.5 with the seat back watching Netflix. In comparison my flight realms are completely dependent on Turbulence, Time Constraints, and Wind. I'll do the same cross country as them between 1000 feet and 10,000 feet based on that criteria. And I think I'll enjoy the journey more than them, as my trip is ALL about the journey, even though it's a XC flight to a destination.

While I do fly higher, faster GA aircraft on occasion, owned by others, and those quite purposefully designed for XC travel, those are not aircraft I have a desire to own for my mission. (My dad had a Musketeer that I flew the wheels off of as a kid, and loved it as well, but it was a different time) The Patrol, as an example, is the fastest, smoothest and best performing aircraft I have owned. But, if my mission was different, any number of other aircraft could be described in exactly the same terms.

My point is that in my experience the Bearhawk is a phenomenal XC machine. Load it up with what ever you can shove through the door, go to Maine, Missouri, Utah, Montana, Alaska. Land where you want, camp as needed, enjoy life. There is a guy that does that in his Bonanza, but that's very atypical. He also can't takeoff and land in 200' when he's empty.

Personal opinion, absolutely. My Point of View differs from others, and I perceive aircraft based on my mission. It's okay it doesn't match another pilot. Just like my paint scheme, modifications, or panel.

Go fly. Enjoy it. Every last minute of it.
pb

ps. My Patrol build will have a Garmin GFC500 3 axis autopilot in it.

[777Ben]

I plan to install rudder trim on the inside of the firewall/behind the panel area using the "springs pulling on the rudder cable" method as another builder has done. My Cessna 195B has the same system, except it's located back in the tail area. I LOVE it. I never flew a single engine aircraft that had rudder trim till the C195. Now I gotta have it. It's just one of those luxury things that's easy to add (and easy to remove if you don't want it. But that's not likely).