Question Taking the Tailwheel Plunge

[lrobichaux]

I've flown my NXCub for a little more than 8 months and ~ 100 hours and I just love it. It's a beast of a plane which has afforded me the opportunity to develop some basic Cub flying skills. Low, slow, short grass strips, windows open ... it's the most fun I've had in aviation ... so far. That said, the internal critic deep in my head constantly reminds me "yeah, that's all great, but it's not a tailwheel." So, after a few months of consideration, I've signed up to but a brand new EX-3 built by an experienced A&P/IA builder who I trust completely. I'm going to own the plane in partnership with my stepson. So this post is combo announcement and request for suggestions / recommendations.

2025 EX-3, CC363i, 83" 2-blade CS prop, 31" ABW, Acme suspension, 3x3 extended landing gear, ABW baby bushwheel with an IFR panel w/ AP, BEW of 1,169 lbs.

@Neal , I've watched just about all of your YT videos, but would appreciate it if you would point me the top 2 or 3 most relevant for a new EX-3 owner. Would also love everyone's opinion on whether the the following is worth the cost: (1) forward facing camera, and (2) dual caliper Beringer brakes.

Comments and suggestions welcome.

 

[Cactus Charlie]

would appreciate it if you would point me the top 2 or 3 most relevant for a new EX-3 owner. Would also love everyone's opinion on whether the the following is worth the cost: (1) forward facing camera, and (2) dual caliper Beringer brakes.

Forget the toys and learn to fly it.

With that empty weight I have to wonder if the builder understood "unusable fuel". The FX-3 has 5 gallons unusable when tested by CC. That's a 30 lb penalty over builders who assume unusable fuel is what is left after draining the tanks with the aircraft level.

 

[lrobichaux]

Forget the toys and learn to fly it.

Yep. Good advice. I've got a little TW time now, and I plan to get 10 hours dual before flying solo PIC.

With that empty weight I have to wonder if the builder understood "unusable fuel".

See attached.

 

[Cactus Charlie]

Well I see 30 lb unusable in there I'm but still surprised at the weight. My FX-3 with 80 inch prop and 26 inch ABW, GPS175, and G5, has an empty weight of 1170 lb. (Extrapolated for post delivery mods from factory weighing).

Maybe you got an unusually light build which should be good.

 

[Neal]

Congrats @lrobichaux - sounds like you're having a blast and that's priority #1. Priority #2 - get some Aeroguard and clean that windscreen

As to the brakes? No, you have grove which I am not familiar with but the brake issue I mention is for Beringer 6 inch wheels/brakes with 31" ABW. I could barely hold the tires at runup without dual calipers.

Forward looking camera? With larger tires it's harder to see over the front but it's just a safety device and I never taxi without it. I've had times where I've landed on a grass strip that has those cone things for runway edge markers and you have to go between two to turn around at the end and I wondered "Did I go between them?" and of course looking for construction cones or anything stupid that wants to attack my credit card. Trent Palmer hit a cone and I think that's when it all started. It's an easy mod but it will require drilling into the lower cowl and installing it. But I love it, as you know.

It seems to me the gross weight is a little low by about 100 lbs but my sample size is 2. My second FX-3 I think is around 1300 lbs for some reason, prior was around 1270. With cargo pod.

I think in your original post you mean IA not AI after A&P? Let me know and I can fix it for you.

 

[Cubonaut875]

My 2 cents: I'd skip the baby bushwheel. No matter what they have a shimmy on pavement, it generally obligates a wheel landing on pavement. On sandbars the regular tailwheel actually acts like a brake. Soft wet grass or snow is where the BB bushwheel shines. I'd skip the whole Berringer wheels and brake fiasco entirely. They are like that decorative couch my wife has that looks great but is totally uncomfortable and non functional.

 

[Cactus Charlie]

I put a baby bushwheel on my FX-3 after I spent about 30 minutes at a remote strip with the standard tailwheel buried up to the axle in mud. The baby bushwheel floats over everything.

I land 3 point on pavement and it took a while to tame the shimmy. Now I sometimes have some mild shimmy that is usually stopped by relaxing the stick back pressure. Maybe one pavement landing in ten I have to get the tail back off the ground.

The shimmy is now infrequent, mild, and tolerable. When I started it was so violent I was concerned about structural damage.

I would not take the baby bushwheel off but I would not recommend it to anyone that is not likely to bury the standard tailwheel.

 

[lrobichaux]

I land 3 point on pavement and it took a while to tame the shimmy.

For the uninitiated like me, what's the process for diagnosing and taming the shimmy?

 

[lrobichaux]

I think in your original post you mean IA not AI after A&P? Let me know and I can fix it for you.

Yes, you're correct. I fixed it.

It's an easy mod but it will require drilling into the lower cowl and installing it. But I love it, as you know.

Cannot remember, but do you have a video on the camera?

get some Aeroguard

I was introduced to Aeroguard a couple of months ago and that's all I use now.

 

[Cactus Charlie]

For the uninitiated like me, what's the process for diagnosing and taming the shimmy?

Single word answer - "protracted".

The first step is to ensure a positive caster angle but I have not changed that as it is slightly positive.

Things I changed were -
Change the tail wheel from internal 3 spring to 5 spring configuration which increases damping
Ensure king pin nut is adjusted for maximum spring compression without pinching and binding
Reduce slack in steering springs/chains
Eliminate all free play in tail wheel spring mounting to fuselage ( I have the standard leaf spring)
Experiment with tire pressure
Eliminate end float in horizontal stab leading edge (lateral motion between stab and drive yoke)

Your photos show a "stinger" tailspring which has adjustable caster angle. Also, Airframes Alaska will sell you a damper for over $1,000 and they have a video showing how effective it is. They also have exploded parts diagrams for the tailwheel and a guide on shimmy mitigation.

Does your baby bushwheel shimmy? If so, have you asked the builder what steps were taken to eliminate it.

 

[Neal]

Cannot remember, but do you have a video on the camera?

Yes, but I left out the part that it is powered. CubCrafters tapped into an existing breaker for 12V power as the draw is so low, and you can ground it anywhere along with other grounds or posts available for grounding. It is super simple, you just have to remember to enable the Video page in the G3X "flying side" configuration, not the Configuration side accessed on startup.

My 2021 FX-3 had the camera lower and further aft which I liked but it is close to the exhaust. The 2023 FX-3 has it on the forward quarter of the lower cowl which caught me off guard when taking delivery of my plane expecting it in the same location as before but it's fine and it is in a better location for heat from the exhaust.

 

[Neal]

I was introduced to Aeroguard a couple of months ago and that's all I use now.

It's the most expensive windscreen cleaner I have used and I've tried quite a few with Plex being my next favorite but I love this Aeroguard stuff. Cleanest my windscreen has been.

Edit: I'll add that I also changed my microfiber towel routine. I bought a mass supply of Costco microfiber towels, they are my favorite. I only use new ones on the windscreen and after a few uses they get demoted to bug towels for leading edge and other cleaning (non plastic/windscreen use). A new towel comes out for the windscreen, repeat.

 

[Cubonaut875]

For the uninitiated like me, what's the process for diagnosing and taming the shimmy?

I tried a lot to stop it, the regular stock spring was too weak for that big tire. With the stinger, I would imagine the shake would transmit directly to the airframe and be rather unsettling. The real solution is to wheel land on pavement and keep it off the ground as long as possible. When I ordered my FX3 I initially wanted a Baby Bushwheel, when I came back for second build there was a standard wheel on the plane. They asked me if I wanted it changed, I thought about it for ten seconds and said to just leave it.

 

[Neal]

At least the last year of my life has been dealing with shimmy, maybe longer. I sadly am stuck to primarily pavement ops which as we all know is where the problem lies. My prior FX-3 had the T3 Tailwheel setup with the classic wheel/tire. I did have some shimmy issues and also made a video but got it resolved. The new plane I went with TK1's new shock monster tailwheel as I like TK1's products, Tony's humble attitude and amazing customer service and I believe in the durability of his product over others. My tailwheel has the 11x4-5 setup so it's a 11 inch tire. I learned from my CFI when expressing concern about messing up fields if going in when they're wet and he said it's not the main tires that do damage, it's the tailwheel, it becomes a plow. So I felt a larger tire/wheel would be a better neighbor for going in soft fields, wet or sand.

Every flight is a test flight for shimmy, land, make some adjustment. Yes, the caster angle is supposed to be most of it and I've gone extreme on caster and yeah, that works, however, too much caster makes the wheel want to rotate 180 degrees and now becomes a contributor to ground looping. So caster has it's limits too. I've tried high and lose tire pressure. No slack in the chains, which what Tony recommended too, to one link of slack. The problem with no slack is the shimmy transfers to the steering arm and you're going to damage something.

I recently loosened and retorqued, even changed the tire to a better Aero Classic tire over the one that Tony ships. Tony's shock is highly adjustable with upper and lower gas chambers allowing you to control the pressure to make adjustments as well as a main clevis. He's been amazing with customer service helping me with this, I know he wants nothing more than to never hear from me again but he hasn't blocked me yet! It seems as if I'm the only one with shimmy problems with his setup but quite frankly I'm probably in the minority landing on pavement of his customers, or no one else is vocalizing the problem as I am. I have swapped the tailwheel setup out for the T3 and shimmy is gone but I really want the bigger tire and of course I paid good money for this.

Trent Palmer has the same setup but a slightly larger tire but the difference is his is NOT steerable, he has no steering arm or link chains and springs. So I wonder if part of the problem is that I'm kicking rudder to keep the nose straight which is causing the tailwheel to touch down angled immediately kicking it into a shimmy? So last week I reached out to Tony with the idea of trying a non steerable setup. Mine is easily switched over by removing the steering arm and putting a spacer washer in its place which Tony sent me, as a courtesy, which arrived yesterday. So that's in the plan after a few more caster angle attempts to see if simply setting the tailwheel down straight has any effect. I hear about speed, etc. and I land 3 point all the time at the stall speed so I can't go any slower.

Maybe a darned stick for a tailwheel is a better idea like the good ole days? There was someone on one of the Facebook groups in recent weeks with his Carbon Cub SS (yellow) and the baby bushwheel sounding just like me, wanting to do anything to stop the shimmy. He's had it and is going from the bbw back to the standard Aero Classic tire. I may end up doing the same but I'm not there yet.

The fun of tail draggers