| Author | Message | ||
     Allen F. Kittleson New member Username: Al38kit Post Number: 2 Registered: 07-2007 |
I'm new to the forum and the airplane, so please forgive the ignorant questions...I've searched for info on converting the cable system to the push pull tubes and can find reference to folks doing it, but nothing of how to do it. I'm sure I can come up with a way, but hate to reinvent the wheel if it's already been done. I have an Express CT I bought in CA. I plan to go through thoroughly, before I fly again. I found the elevator control cables to be so slack, that with the stick secured, the elevator could almost be moved stop to stop. If others have been happy with the response of the cable system, properly configured, I'd like to hear about that too. Thanks in advance, Al Kittleson Granbury, TX 817 326 1437 | ||
| Michael Farley New member Username: Mikefarley Post Number: 6 Registered: 11-2006 |
The original CT was designed with cables running from just behind the main spar carry-through all the way to the elevator bellcrank in the lower tail. Is your new airplane equipped properly? By that, I mean would fixing the problem be as simple as tightening the cables? The elevator turnbuckles are located right behind the carry-through...you can always tighten them up and see how the system works...I can't remember the proper tensions, but you can at least hand-tighten them to check the integrity of the system. If a fix is as simple as that, it may save you a lot of work. I know of several Expresses that are CT designs with the elevator controlled with a pushrod, but we're sticking with the original design using cables. Congrats on the airplane, by the way! Do you have any pictures of it??? Mike Farley | ||
| Allen F. Kittleson New member Username: Al38kit Post Number: 3 Registered: 07-2007 |
Thanks for the post Mike. I have thought about tightening the cables and will give it a try. I also have several pics, the plane is a "work in progress". Still needs paint and interior...I will probably go through it all. I have a new set of wings available that need to be built, as well as aluminum gear. I'm giving some consideration to doing all this before I fly again, as I understand the flight controls with the needle bearing work better. I would also like to retro the fuel system to only one tank/filler per wing... Al | ||
| Jim Ward New member Username: Jehward Post Number: 55 Registered: 02-2000 |
Al: I changed my aircraft cables over to push-pull sheathed cables (prior to first flight). I just looked, and do not have any pictures of it. I can take some this weekend if you would like. They basically replaced the aircraft cables, run the same route from the rear of the wing carry-thru back to the elevator bellcrank. The trick with the sheathed cables is to secure them so that they do not squirm around. I did this right behind the baggage bulkhead by tying them to the floor. From there, they go up to the tail bulkhead and thru a tunnel to the bellcrank. I can't say this is any better or worse than the aircraft cable system. When I secure the stick, there is absolutely no movement of the elevators when pushed from the outside. The sheathed cables took some trial and error in finding the right clevis combinations. Let me know if you want ot explore this further. Jim | ||
| Jay Villalva New member Username: Jay Post Number: 11 Registered: 11-1999 |
If you get to the point where you want to convert to push-pull tubes, I can provide photos and dimension of what I did. I have CT tail feathers. It’s a lot of work to rip out your existing system and if you change one thing – you’ll end up having to change three other things. There are pros and cons to the push-pull tubing. The reason I choose to change my system was the desire for full travel and positive elevator control . There are some good pictures in the photo gallery (www.express-builder.com/gallery) of factory photos that show different versions of the installation on the low tail model. There are at least two different systems shown, one using push-pull cables for rudder control and another using the old style cable and pulleys. | ||
| Allen F. Kittleson New member Username: Al38kit Post Number: 4 Registered: 07-2007 |
One of my concerns with the cable system is the integity of the attach points for the forward cable pivot attachment, as well as the pulley attachment on the belly. I suspect if properly installed, this should be no problem and something that I need to carefully inspect on this airplane. It looks to me that if the cable tension gets high enough to take out the slack in the system, that these points will have to be very solid. I was not happy with what I saw in the forward pivot spot and need to take a good look at that before I decide to stay with the cables...regardless, I think this is a major player in the integrity of the system. The other concern I have is coming up with an interface for an elevator servo on the autopilot. My thoughts were that the push pull tubes would make a more solid platform for the autopilot input, but properly placed servos for the cables and proper rigging should allow for this to work also. Any thoughts on A/P servo interface? If folks have found the cable system satisfactory, I suspect I will stay with it. I'm really not into making more work for myself...I got over that years ago. Al | ||
| Bill Copeland New member Username: Cbros Post Number: 43 Registered: 09-1999 |
Allen: We have hooked our elevator auto pilot servo to the standard cable system in our CT and it works just fine. We have over 700 hours on ours with no problems with the cable control system. Proper tensioning is very important. We also installed the "forward pivot point per the original manual with no problem so far. If you are really concerned you might consider riviting or bolting through the "V" bracket to a hard point in the outer skin/foam fuse bottom. Bill C | ||
| Reinhard Metz New member Username: Reinhard_metz Post Number: 80 Registered: 03-2003 |
My CT has been flying 9 years and over 700 hours with the original cable set-up with no problems. Never had to re-tighten them. Feel tight and crisp. And I also have the autopilot clamping onto the cable with a servo that drives a drum. Standard STEC set-up. What I would be concerned about is why these cables were so loose - is something broken? I would check that very carefully. As far as the fuel is concerned, I would highly recommend staying with the 4 tanks - much more convenient if you are in the habit of "topping off". With only 2 tanks you will always be carrying excess fuel, unless you always and only take long trips. Reinhard Metz n49ex | ||
| Bill Copeland New member Username: Cbros Post Number: 44 Registered: 09-1999 |
Allen: Reinhart is right- there is no way the cables should have been that loose. Perhaps one of the cables has slipped off a pulley somewhere. One other thing that you are not going to like to check is the security of the welding on the "gears" on the elevator torque tube assembly. There is one documented case of one of the "gears" actually falling off. If you need a pic to identify what I am talking about, I know I have at least one that I can send. (Hi Reinhart!!!) Bill C | ||
| Jim Ward New member Username: Jehward Post Number: 56 Registered: 02-2000 |
Al: Now that you've posted pictures, I can see that this is the airplane that came from Cameron Airpark. From what I can remember, I believe that at least one of the elevators had been taken off the airplane. The cables might have been loosened to facilitate that. I believe that the gears that Bill is referring to are on the rudder torque tubes, up in the forward area under the panel. Good to see the Forum active again!! Jim |