| Author |
Message |
    
Brynjar Thordarson (Benny)
| | Posted on Tuesday, December 17, 2002 - 11:36 am: | |
This is for lvillalva:
I did it. I replaced the elevator cables with the push-pull system. It's a bigger job than you could imagine.
If you want pictures then send me a private E-mail and I'll send them to your private address. No reason to bother the other guys with them. It took a lot of headscratching to figure out how to route the rudder cables after the mod, but all is possible.
My documentation from Wheeler says elevator 25°up and 15°down. Any comments?
Once I told Jerry that if he feels that he's running out of elevator on flare all he had to do was hurriedly trim full nose down and let the tab assist. (Obviously the elevator force would be increased). By doing that you increase the elevator up surface. He thought I were joking!
Best rgds. |
wayne
| | Posted on Tuesday, December 17, 2002 - 02:14 pm: | |
This is an interesting airplane and this is just FYI on my 2000 series. I took off with full fuel, leveled at 2500',one quick blip of nose down trim. Flew for 3 hours, landed for gas,took off flew another 20 min. landed, took off and flew home, 2.5hours and did NOT touch the pitch trim but the one time.
There is some initial pitch forces when you start to put out the flaps, but they go away as the speed slows. The pitch forces are so light that what ever is there, once the trim is set, you forget it.
When I fly with the family on board, more aft CG, I still don't change the trim position much once it is set.
You got to LOVE this plane, I am finding that I really like to fly it. Just wish it was a little faster.
I would change the stab to -1 degree to get rid of some of the up elevator that it always has.But then we're talking apples and CTs. |
jvillalva
| | Posted on Tuesday, December 17, 2002 - 08:41 pm: | |
Great discussion everyone. I have already installed the my elevator push-pull system - I wanted to make sure my system had the control travel necessary for the required elevator travel. With the numbers I see here, that's not going to be a problem.
For anyone that is interested, I used the push-pull system being that is currently being used for the 2000 Series. I had to raise the height of the aft shear web (for mounting of the combined elevator/flap bell crank/support bracket), shorten the length of the aft push-pull tube, install a mounting plate for the aft bell crank (just aft of bulkhead 162) and the aft bell crank (the one that connects to the vertical (almost) elevator push-pull tube) is different.
Interesting comments by Wayne on the light pitch forces on his 2000 Series. Maybe this is why the pictures in the express-builder gallery show the fwd elevator bell crank being drilled closer to the torque tube. I suppose someone wanted their controls a bit heavier.... just guessing. |
Mark Rich
| | Posted on Wednesday, December 18, 2002 - 08:23 am: | |
I also have push-pull tubes in my CT. I'll post the elevator travel numbers once I have a chance to re-check.
One problem I ran into with the push-pull system was clearance for the rear seats. I left very little space between my seats to make the seats as wide as possible. There is enough space at the back of the seats to clear the old cable system but not enough to clear the higher push-pull tube.
I debated making the seats narrower but decided in the end to lop off the inside corners of the seats and beef-up the joint with some additional layers of UNI. I cut the seat at a 45 deg angle with respect to the side of the seat. Seems to work ok but I had to do it twice since the first time I didn't allow for the flex in floor when the seat was loaded. |
Michael James
New member
Username: Mjames
Post Number: 1
Registered: 05-2004
| | Posted on Friday, June 11, 2004 - 05:18 pm: | |
I am in final assembly of my aircraft and in attempting to hook up the elevator cables, discovered the geometry is not right. This is one of the first express design retrofit kits. The problem lies in the fact the cable pulleys at bulkhead 162 are not at an equal distance from the ends of the bellcrank when it is in the "neutral" position for the push-pull tube to the elevator horn. There is a similar alignment problem coming off the "v" blocks to the horn at the spar. Is anyone aware of an easy fix??.... there is no way the cables can be tightened with this set up. I would appreciate info from anyone that is familiar with the issue. |
Roger Spencer
New member
Username: Roger
Post Number: 38
Registered: 05-2001
| | Posted on Tuesday, January 03, 2012 - 07:42 pm: | |
I'm just about to rebond my aft fuselage and decided to rig my hoizontal tail and elevator to check the fits and rough alignment and discovered the problem that Jay Villalva identified on 17 Dec 2002 with the clearance for the elevator push pull rod. My kit is a combination of the original Wheeler,Aureiga,and 2000. It uses the 2 shielded cables for the rudder. I have the correct higher aft fuselage shear web to mount the flap/elevator bell crank and proper bell crank and instructions for the bellcrank aft of bulkhead 162. To solve the clearance problem with the push rod and rear seats I raised the seats enough to get clearance and inlined them slightly to keep adequate head room. However,alignment of the aft push pull rod for the elevator with the bellcrank lever on the elevator it appears that approximately 1/2 ench of the aft hoizontal tail shear web and some of the lower HT skin will have to be removed to clear the push rod and the push rod will have to be shortened approximately 2-2.5 inches. The aft lower horizontal tail metal support has a cut out for the push rod that goes up onto the HT rear shear web so I imagine that it was the design intent to remove that material. However nothing in the documentation talkes to this. I realize the horizontal tail spar is there to take vertical air loads but the shear web has to box the structure to help take out twisting loads. Has anybody seriously looked at the potential structural impact of removing a 1/2-5/8 inch deep 1 inch arc from the bottom of the elevator shear web? I suspect that the affect is not significant for desisgn loads but wanted an opinion from some of you that have may have already considered and done it. |
Gary H. Wolfelt
New member
Username: Wolfelt
Post Number: 64
Registered: 11-2003
| | Posted on Wednesday, January 04, 2012 - 06:56 am: | |
Roger: This is the part of the project that Dan Roundtree (Express Builders Assist) and I most recently completed this last summer. We had to do exactly as you have described above to make things fit/work. Since Dan has a tendency to reinforce everything that he touches, I am not the least bit worried about removing a bit of composite material. We also had to open up the hole in the aluminum bracket to get the rod to clear properly. And I even had to take the large push-pull tube back to Steve Furjesi's shop to have a few inches removed so that it would fit. So it sounds to me like you are on the correct path. I am just happy that I don't have to make these kinds of decisions on my own and have Dan to help lead the way. He has so much experience and knowledge that it takes a lot of the misery out of building. But I only get to go work on my project (in Washington) for two weeks every summer. So I am moving more slowly than I would like. And of course the cost of getting and staying there for two weeks hurts a bit. But the time that I am there is very well spent and we are focused every day.....no other demands on my time. I have attached a photo of my project outside of the Express hanger just before I put it away for another year. Notice the nice hi-tech "engine" that Dan fitted to my airframe to keep us inside of the weight and balance numbers. GHW |
Roger Spencer
New member
Username: Roger
Post Number: 39
Registered: 05-2001
| | Posted on Sunday, January 29, 2012 - 05:17 pm: | |
Gary, Do you know how much you shortened the large push pull rod. I don't see a simple way to measure how much to remove. As best I can estimate it requires shortening by about 3 inches but I don't want to get into a trial and error operation if I can avoid it.
Your airplane looks good. How did you dress up the gap between the horizontal tail and the fuselage? I got a large gap around mine. I needed it for access to bolts and to allow shimming if required for tail alignment. I've been anticipating having to build a large fillet similar to the main wing to cover it. |
Louie Lacy
New member
Username: Llacy
Post Number: 102
Registered: 10-1999
| | Posted on Sunday, January 29, 2012 - 07:34 pm: | |
Don't know if this is the place for this info but here goes. I crossed the Great Smokey Mtns twice today. Wind at altitude was from 290 at 50. As I started a let down from 10500 at 195mph I was in moderate turbulence. All of a sudden the nose started to vibrate(for lack of a better explanation) side to side. As you might imagine this was rather disconcerting. I have a Tru Trak autopilot and when I turned it off the vibration stopped. I am looking for a possible explanation.Could I have an aileron riggin problem e.g. loose fittings etc. The Express CT has 815 hours and this has never happened before.
Lou Lacy |
Gary H. Wolfelt
New member
Username: Wolfelt
Post Number: 64
Registered: 11-2003
| | Posted on Sunday, January 29, 2012 - 07:42 pm: | |
Roger, I cannot give you an exact measurement as I discarded the cut off piece. But what we did was to mount the sizzors block and attached the rest of the rods, etc. then we got the everything neutral and then crawled back into the tail and marked the tube for the approximate proper length and then made the final adjustment on the rod end. But I am guessing that the cutoff piece was about 1.5 to 2.0 inches in length. I can see no reason why these parts cannot come out of production the "proper" (standard) length especially since the cone on the ends of the push-pull tube are welded in place. I expect that this is just another error that has followed through since the project was turned over after Larry's death. But Darrell and Dan (and Steve Furgessi) are working hard to get things standardized....just not there yet. As for the gap that you mentioned, we didn't have one. Dan was very careful about that and he has a special "tool" that he made for installing and removing the bolts up in the slot. You might want to take a vacation and go visit these guys to take a look at what they do and how they do it. There are lots of "tricks" that you and I would never figure out on our own. I will send you a couple of more photos (off forum, so I don't hog up space) for your review. GHW |
Brian McKinney
New member
Username: Bmckinney
Post Number: 111
Registered: 05-2000
| | Posted on Monday, January 30, 2012 - 09:21 am: | |
Roger,
You can make a cheap template push-pull rod from pvc pipe with end caps & thread in the rod ends to figure out your exact needed length. I believe Jim Lewis had pictures posted of doing this a few years ago. Jim has come up with many good mock-up templates of various parts for his plane before he modifies the expensive real parts. His wire frame engine cowling was one to remember...  |
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