| Author | Message | ||
     AndyFawcett New member Username: Drew Post Number: 6 Registered: 03-2003 |
Related to control play: In our early flight tests we find a fairly significant dead-zone in the rudder which may be due to stretch in the pull-pull cables. Extra cable tension improves the problem but it still looks marginal. A second issue is the flap motor. Pressure on a deployed flap can move it fairly easily (We get no differential flap movement). We are curently repositioning the motor from the right wing to inside the fuselage but I wondered if anyone had experience of this problem. Any thoughts? | ||
| Jerry Sjostrand New member Username: Jerry Post Number: 55 Registered: 08-1999 |
Kevin; I had the same problem with the torque tube play and took care of most of it by using "0" tolerance AN5 (5/16") bolts and reaming with a "o" clearance reamer making sure the "grip" portion of the bolt goes all the way through the parts as suggested above. You do not want the threads to be in play. The joint should have been designed with shoulder bushings, etc., but wasn't and there is no room now with the parts as manufactured.  Good luck, Jerry | ||
| Ted Gaston New member Username: Ted_gaston Post Number: 8 Registered: 09-2003 |
Andy, I presume you are asking about S2000 RG configuration. 512EA had the same problem. We made it better by making a new horn for the rudder thus reducing the mechanical advantage at the cable. Since we are talking about a S90 rudder, our configuration was different than yours but the pricipal remains the same. Mechanical advantage overcomes cable tension. We were exploring sheathed, roller bearing steel push pull cables available from Brookhurst Industries when 512EA crashed. As for the flap movement you described. We found that the lower skin extension to which the flap hinge is attached was inadequate and built in a gusset from the rear spar to right up close to the hinge. That helped a lot. | ||
| Charles M. Robinson New member Username: F15epilot Post Number: 32 Registered: 02-2004 |
Since we're on the topic of free play in the controls, perhaps someone has a solution to mine. When we finished the painting of 336FS, the paint shop owner pointed out that with the left aileron at full deflection up, and the stick held full left and aft, you could move the left aileron up/down a fair amount (about +1" and -3/4" at the trailing edge). I removed the pilot seat to ezamine why and found that the push rods from the left side were moving the aileron/elevator torque tube left/right in a sliding motion. This was a combination of several things that combined to allow the movement: a slight flexing of the fiberglass the end bearing blocks are mounted on, slight flexing of the bearing blocks themselves, a slight amount of sliding L/R free-play in the bushings the troque tubes slide on, and a slight amount of clearance free-play (up/down) in that same bushing. It's somewhat hard to describe, but if you picture the assembly looking down from above, then set a point of rotation at the connecting point of the control stick interconnect rod (rod between the two control stick bases), pushing down on the left aileron causes the back of the control stick base to rotate counterclockwise slightly due to the sliding and flexing. It is not a problem when the stick is pushed back forward of neutral elevator or with a right stick deflection. I want to recheck the balance all of the flight controls (to see if the allowances made pre-paint were accurate) and want to tackle all of this in one shot. Thus far, I haven't noticed any adverse flight characteristics--if anything, the plane handles better, especially slow (it floats a lot more on landing--guessing the lack of 'rough' surfaces is at work here). Any advice from you experts? Thanks Chuck | ||
| Ted Gaston New member Username: Ted_gaston Post Number: 9 Registered: 09-2003 |
Chuck, that's a common condition with these stick bases. Make sure there is no play in the push/pull tube assy between the aileron and the stick base. Then work the issues as you find them with a combination of shims and bolt substitution. You may even need to rework the stick base to tourque tube connection to get the play out. With the roll rate of the Express it is important to have as tight a connection as possible in the aileron system or you might run into problems at slow speeds. Besides, who want's a sloppy airplane. | ||
| kdennes Unregistered guest |
Thanks Ted and Jerry (and 'Freddo' who called me from Alice Springs). I will try the extra bolt length first and then if that doesn't solve the problem I will have to look at the reaming route. I appreciate your helpful comments. Regards Kevin (from Downunder) | ||
| kdennes Unregistered guest |
Greetings all. Would those of you who have completed their 2000 series aircraft advise me of your "unusable fuel" quantity please. I am interested to know if there is much variation between the various projects. Regards. Kevin (from Downunder) | ||
| wayne Unregistered guest |
I have 38 US gal a side total, all but a quart is usable. First time I put gas in, I put in 5 gal a side. Then I took the line off at the engine driven pump and used the aux pump to pump the fuel out and back into the same 5 gal can, 4.75 came out.so there is about an "old can" left mate! | ||
| Charles M. Robinson New member Username: F15epilot Post Number: 33 Registered: 02-2004 |
I have an Auriga (kit #14) which should be the same as the Series 90; believe the newer wing has more fuel. During flight testing, I ran each of the 4 tanks dry to a) get a feel for any adverse flight control issues from the ensuing asymmetry; and b) measure the 'usable' fuel in flight attitude. I had filled up each tank after completion to get the total capacities. Here are my numbers: Left & Right outboard tanks: 20.0 gal // 19.5 gal usable Left & Right inboard tanks: 26.0 gal // 25.5 (L) & 25.6 (R) usable Total Capacity (to the edges of the filler caps = 92 gal // usable = 90.1 While I don't recommend flying a tank to empty as a matter of course (especially with passengers aboard--it really gets their attention!), I did get a good idea of the 'hints' that a tank is about to run empty (important as the outboard tanks don't have fuel sensors in my bird). In my plane's case, the fuel flow shows a sharp rise about 5 to 8 seconds before the engine begins to stumble. It's ample time to kick on the fuel boost and switch tanks. Like knowing your hypoxia symptoms, for me I like knowing what that sounds like for those rare times I get distracted from my tank switching schedule. I also found it interesting that having a left-wing-heavy fuel asymmetry (empty right tanks) was harder to trim out and put me closer to running out of roll authority than a right-wing-heavy (yeah, I was sitting on the left side, so I repeated it with 175lbs in the passenger seat--almost same results). For the record, I keep the tanks balanced while flying--the asymmetric exposure during the 25 (no wait--DAR later made it 40) hour flight test gave me some concrete reasons why that's important (and helped fill up the POH!). Chuck | ||
| stan susman New member Username: Stanpfa Post Number: 11 Registered: 01-2003 |
Gents and ladies, I spoke with BRS (the Cirrus parachute folks)this week to hassle them about not offering a system for higher speed and gross weight birds like our(experimentals). Let's not get into a discussion about if they're needed or not. I belive that Cirrus sells a lot of airplanes because of them and am intrested in increasing the market value of our birds to at least what it should be. I digress/ BRS told me about product liablity, engineering resorces,ect.ect. bla bla bla. Anyway,that's all behind us now and they're very willing to talk . They have all but caught up on cirrus production and could (after details are ironed out)offer a slightly simlified verson of the SR 20/22 unit. The next question is ,Am I the only one that has an intrest in this pursuit or are there others that think it may be a good idea? What say ye? Stan |