Rudder stops

[L.Adamson]

I'm still lost on the benefits. If the complete rudder control mechanism was hidden from view, then I see the advantage. But once you add exterior rudder cables and the rudder horn to the equation, then hows a piece of triangular aluminum for the stop going to make much difference in looks. It's that cable & linkage that isn't pretty!

L.Adamson --- RV6A

[pierre smith]

Originally Posted by Maxrate

Pierre,

What did you use to shim the block to get the perfect fit.

PS: I flew with a guy the other day who was a turbine Air Tractor driver. Looks like a real Cadillac.........

Thanks

....since the blank piece came from Spruce and after I cut it out on my bandsaw, I had to spend quite a bit of time on my belt sander to thin it down to fit.

Yep, the 'Tractor is pretty much the ag airplane of choice but the Thrush drivers won't change airplanes for anything.

Best,

[Maxrate]

Pierre,

I see. You actually fabricated your own. The one I purchased from Craig is too thin and will need a shim. As a Tech guy is there any recomendations on what you would use. Are AN washers OK?

The most amazing thing to me about Ag ops is how far GPS technology has advanced operations. He was able to operate into the night with no flagmen.......Amazing.

Thanks for the input.

[Andy Hill]

On the other hand....have you ever seriously reviewed the stress issues?

Dan,
When do we expect these stops to come under stress? Only 2 conditions I can imagine are at full deflection either by pilot input or in the case of an unrestricted/unrestrained rudder being blown by the wind. Of these 2 which one are we most concerned with? I believe I have read of rudders being bent by the wind when a rudder gust lock was employed.
Dave

I should hopefully see very infrequent full rudder deflection, as was demonstrated to me in my transition training in Vernonia, since brakes are used so often in ground steering, and full deflection on short final indicates the landing is likely beyond my capability this early on. Later, who knows.

I am one of those who query this "modification" for stress reasons.

In answer to

When do we expect these stops to come under stress? Only 2 conditions I can imagine are at full deflection either by pilot input or in the case of an unrestricted/unrestrained rudder being blown by the wind

I am not really concerned with either. They will not kill you, and most likely, if any damage were to result, visible on a walkround check, and just cost ??? (or $$$!) / time.

My concern is a 3rd condition - a (presumably) inadvertant tailslide. This, to me, is the ultimate "stress" for a Rudder Stop (and Elevator). It takes a scr*wed up aerobatic manouevure, and a mishandled recovery... however, I have seen both together, both by me and more frequently, students... If you have not done a tailslide, please let me assure you the control forces as they reverse are harsh, and if you fail to hold them, a real hard/fast application of full rudder / elevator

The problem in the RV case is that if the "modified" rudder stop fails (in fact, I doubt it will be the stop that fails, it will be the rudder) what now stops it? Well, the elevator, and rudder jammed into elevator only equals one outcome

So to me it is a risk benefit analysis. The "benefit" is a slightly more sexy looking rudder stop. The risk? Death to both occupants probably.

So to

but I've never heard of any actual problems or data to support their findings

I am glad you have heard of no problems... just when/if we do, they are likely to be major. As for data - surely it is not us that have to provide the data? Van's provides the design, presumably to an accepted protocol / design standard. It is surely up to those who choose to override this should provide the data to "prove" their alternative is equally, or more, safe than the Van's design?

Please do not get me wrong. Anybody who chooses to modify their design at their risk I am fine with - we all take risk/benefit decisions every day. My concern is with those who encourage others, without expressing all the facts, to modify the Van's design, and even make $$ out of it. Go back to the original RV-3 design issues and fatalities, and the RV-8 prototype accident... In my interpretation, Van's design in both cases was proved correct, but not far off optimal

Andy
RV-8 G-HILZ

[Flying Scotsman]

Originally Posted by Andy Hill

My concern is a 3rd condition - a (presumably) inadvertant tailslide. This, to me, is the ultimate "stress" for a Rudder Stop (and Elevator). It takes a scr*wed up aerobatic manouevure, and a mishandled recovery... however, I have seen both together, both by me and more frequently, students... If you have not done a tailslide, please let me assure you the control forces as they reverse are harsh, and if you fail to hold them, a real hard/fast application of full rudder / elevator

The problem in the RV case is that if the "modified" rudder stop fails (in fact, I doubt it will be the stop that fails, it will be the rudder) what now stops it? Well, the elevator, and rudder jammed into elevator only equals one outcome

Is this event within the designed flight envelope in the first place?

[sblack]

Anyone have the cad file for the internal stop? The only link I could find is dead.

[BlakeFrazier]

Hi Scott,

Looks like a pretty old thread you've dug up, which is probably why the links are broken. We carry the product discussed here on our website here: https://flyboyaccessories.com/produc...al-rudder-stop

[sblack]

Originally Posted by BlakeFrazier

Hi Scott,

Looks like a pretty old thread you've dug up, which is probably why the links are broken. We carry the product discussed here on our website here: https://flyboyaccessories.com/produc...al-rudder-stop

Yes I’ve seen it. It looks great. I have a cnc machine so I wanted to cut my own.

[Scott Hersha]

I have a similar setup on my RV6 build. It’s made out of aluminum bar stock. The original rudder stop from the kit builder I bought it from made two of these (top pic below), so I decided to use both of them, one on the top of the rudder bottom clevis mount and one on the top. I needed a spacer between the clevis mounts to not put too much squeeze on the bottom rudder rod bearing so I couldn’t insert it.





When I did this I had to file the two pieces to make them match exactly, and that resulted in a max rudder deflection of 35* (the upper limit), and too close to the limit for my comfort, so I made a new one out of 1/8” stock. I still bolted it to the bottom rudder rod end clevis using a spacer to prevent squeezing the clevis too much, but it works very well. My max deflection is now 32.5*, which is right where I want it.
To me, I prefer the internal rudder stops, and they are easier to install and adjust.

[Joe]

Originally Posted by sblack

Anyone have the cad file for the internal stop? The only link I could find is dead.

I don't see a copyright notice on it so here's a PDF of the design Rene Bubbeman did 17 years ago.

If you email me (jdubner@yahoo.com) your email address I will send you a DXF and/or a DWG file of it.

--
Joe