Control Lock Idea

I've had some down time lately at the day job twiddling my thumbs watching the clock on my computer tick by so I've had some time to do some thinking.

The first time I flew a rental DA-20 Eclipse I was impressed with the control lock they have. It's simple, you don't have to worry about forgetting to remove it before flight, and it's one piece that locks the ailerons, elevators AND rudder in place.

I can see no reason this would not be a good design to work on the RV. If you make the stick-to-rudder pedal tube adjustable/telescoping it will work regardless of where the builder has placed his/her rudder pedals. I can also see no reason this wouldn't work well on every RV model. The only modification required on the plane would be installing the clips on the underside of the panel.

The drawings make it look like a complicated affair, but believe me it's butt-simple. Once it's adjusted to your airplane you pull it in and out in as long as it takes you to snap the two straps into the connectors under the panel.

So what do you folks think?

Here's the control lock from the Eclipse manual:

I tried to make something like that over the winter for my RV-6A. I made two different prototypes out of PVC tubing. Cut the tubing length wise to form 1/2 rounds for cupping the rudder pedals on the lower tube and the stick trying to give it more rigidity. I used velco around the stick like in your first picture. I used a soft bungy chord to hook to the panel as in your picture 2. Never got it to hold real stiff. I could slightly wiggle the rudder or aileron and eventually get it to loosen enough to get more play in the systsem until eventually after 20-30 wiggles the gust lock was not actually doing anything. I then tried one using a telescoping mop handle with some fittings welded to the end. This was to just jam the rudder pedals forward with the telescoping rod up against the front of the spar. Still no real sense of security.

I ended up buying a York gust-lok from Spruce.

http://www.aircraftspruce.com/catalog/pspages/yorkgustlok.php

Works great but weighs more than I wanted.

Here our rudder lock ... http://www.checca.net/n468acrudderlock.htm

Then we use the seat belt to hold the stick back ... works great and can't get in the phane with it connected.

Proper control locks fit at the surfaces not at the stick/ pedals. My whole set of locks weighs about 4oz with flags and takes maybe one minute to install or remove. I have a U shaped piece of 1/8 welding rod which goes through holes in the rudder stop and horn, a fabbed aluminum wedge (padded) with elastic cord to fit between the outer aileron gap and wing tip, hooking around the aileron hinge point and a spring loaded plate system for the elevator fitting between tip and counterbalance.

I always do a control check of course and control lock removal is on the checklist as well.

rv6ejguy said:

Proper control locks fit at the surfaces not at the stick/ pedals.

Click to expand...

Why?

I don't have vast flying experience, but just about every certificated airplane I've flown uses a control lock in the cockpit.

Any slop in the linkage, cables, rod ends just causes the wind to wear everything out with many minute movements. If the plane is parked outside most of its life internal control locks are a bad idea. If you are just parking for the day, they are ok.

Most cert planes with the pin through the yoke idea do that for convenience. If it was too involved, many pilots would not do it. Many don't have rudder locks at all.

I hate to see or hear my RV surfaces hitting the stops in the wind so I take my locks everywhere.

Looks Great!!

Jamie said:

I've had some down time lately at the day job twiddling my thumbs watching the clock on my computer tick by so I've had some time to do some thinking.

The first time I flew a rental DA-20 Eclipse I was impressed with the control lock they have. It's simple, you don't have to worry about forgetting to remove it before flight, and it's one piece that locks the ailerons, elevators AND rudder in place.

I can see no reason this would not be a good design to work on the RV. If you make the stick-to-rudder pedal tube adjustable/telescoping it will work regardless of where the builder has placed his/her rudder pedals. I can also see no reason this wouldn't work well on every RV model. The only modification required on the plane would be installing the clips on the underside of the panel.

The drawings make it look like a complicated affair, but believe me it's butt-simple. Once it's adjusted to your airplane you pull it in and out in as long as it takes you to snap the two straps into the connectors under the panel.

So what do you folks think?

Here's the control lock from the Eclipse manual:

Click to expand...

Jamie,

I think it's a GREAT IDEA! And... I don't think anyone will take off and kill themselves with this idea either. Nice Work!

I disagree with the statement that internal locks will cause appreciable wear. 38 year old Cessna Cardinal that sat outside almost all it's life is still doing great. Internal locks work fine, and there is a much smaller chance of forgetting those.

stay sharp

an rvator came to my local airport last year and was in his plane running up and was ready to taxi....i noticed his locks in the aileron i walked over and was noticed, he watched as i removed them.. he was gratefull to say the least....now i am sure he would have caught that but still it was the first step in potentially bad sequence. with the push pull tubes i think a control lock will be fine in my airplane. however it will all most always be in a hanger so no biggie for me. stay sharp use your check list

Home vs Away

A Citabria friend of mine built a great control lock/panel security device that he takes off and leaves at home. The plane is stored in an open T-hangar, so security is the bigger issue. It's a complete panel cover with a vertical tube that's welded in front of and protrubes down to capture the control stick. It gets locked around the cabin frame tubing at the top of the glareshield. A similar design could be ideal for the -3, -4, and -8 and with some innovation for the (yawn) other RV versions, too. Not something you'd travel with, so maybe one of the PVC designs is best for that. I can take some photos this weekend if anybody is interested.

osxuser said:

I disagree with the statement that internal locks will cause appreciable wear. 38 year old Cessna Cardinal that sat outside almost all it's life is still doing great. Internal locks work fine, and there is a much smaller chance of forgetting those.

Click to expand...

I was just talking to an A&P (we call them AMEs up here) friend here a couple months ago. They had a Tiger in for major repairs totalling about $8K to replace cables, hinges, rod ends, rudder parts etc. Been parked outside in Southern Alberta (very windy place) for 2 years with just the yoke pin in place. Totally trashed a lot of parts.

A lock on the stick is like having a wide open throttle stop on a throttle linkage at the carb end rather than the actuation end. I've seen many cables broken over time in performance cars with this improper setup as the cable is heavily loaded at WOT.

Not doing control checks before every flight is not smart as we saw with the tragic VLJ crash last year. Make it the first item on your checklist.

As I said, for parking for the day or the week, yoke locks are fine but for long term use, external locks are better. The RV rudder with cable actuation is the easiest to damage and the hardest to lock internally but so easy to do externally. It's surprising that after some people build a whole RV- they can't build a simple set of control locks or a lightweight towbar?

I'll take some photos of mine and post them on my 6A site.

What about these gust locks?

What about something like this (first item on the page)--doesn't look like it's that hard to make?

Mike

This is more along the line of what I use and the same philosophy that the surface should be locked, not the control linkage back in the cockpit.

Internal vs External locks: If it's rigged so poorly that wind can cause $8000 worth of damage in 2 years, what's it gonna do with a 200MPH wind and engine vibration when the thing's actually flying? Nevermind the thousands of aircraft with nothing but yoke locks (ala' Cessna) or a seat belt wrapped around the yoke/stick (ala Pipers and Citabrias).

Personally, my favorite is the seat belt wrapped around the stick. I don't know why RV'rs don't just do that.

jcoloccia said:

I don't know why RV'rs don't just do that.

Click to expand...

We do (well, I do!). Just be sure it's off before you fly. Wish I was kidding.