RE: Clevis Probs
 

Thanks!! All good advise. I did call JR and the guy said sound like a bad POT. I dunno.. thought about buying another one just to see what they tell me and sending this one in. Almost wonder if they all do this from defect.

One question on cumn thru's comment "Also make sure the hole that the servo sits in is not too tight". If it is not tight.. how do I make sure it stays in? I don't want to thread lock in case I need to adjust.. right?

Also... I never understood the servo mounting. The ucd manual says to drop some CA in the predrilled hole.. wait till completely dry.. then mount through the hole. That seems crazy to me... why not put it in while wet so it will stay.. what is the point of screwing into completely dry glue.

That will be the last of the newbie questions. Thanks everyone for the help.

RE: Clevis Probs
 

On the screw holes, the procedure is to drill the hole, mount the servo, remove the servo and add a drop of thin CA to each hole, let dry. What that does is harden the area and the "threads" in the wood made by the screws inital passage. Once dry mount the servo. On the "servo hole", I mean, the rectangular cut out in the fuse or wing that the servo sits in. If its too tight, as in having to force the servo in due to the tolerances being too tight, just sand the opening a little so the servo goes in to position easily. If the hole is too snug you again cancel out the isolation factor that the rubber mounts provide. I guarantee if you back off on the servo mounting screws slightly allowing the servo to rest on the rubber the twitch will go away. Joe

RE: Clevis Probs
 

I didn't read all the way back through the thread so this might have been discussed already.

Are you running a 5 cell, 6 volt pack in your plane? IF so, JR's get pretty jumpy if you don't have a voltage regulator to step the volts down a bit.

RE: Clevis Probs
 

Shogun.. I am not sure on the bat pack.. i will have to look. It is in the tail of my plane and I want to fly today.. ha. I think it is a 4 (4n1000 or something like that).. came with the heli promo pack 5ds811's, 8103h, and upgraded to r770 receiver pcm 7 channel from the r700 7 channel fm. Got it for like $450.. .seemed like a good deal (maybe too good). If that turns out to be a 5 pack... where would I find this regulator (wouldn't be able to tell a good one from bad).

cumn thru... I increased the size of the hole (BIG).. loosened the screws to where it just touched the rubber (not even tightened).. still had the problem. I am not ruling this out.. could be that my screw holes a so far apart that when i tighten the screws down a little that they are causing the tightness by themselves, but, I kind of don't think so?

I have read a lot of posts with problems with the ds811's and 3d throws. Some talking about not being compatible with some fm receivers (from jr guy on rc universe), some saying didn't matter what receiver.. i dunno.

I am just going to decrease my throw on my rudder so I can go fly today. Hate having this thing down!! Thanks everyone for their help. I will keep searching and will post the ans if I find the problem.

RE: Clevis Probs
 

c016Y, This is screwy. I tried all of the above mentioned suggestions, just short of a regulator, and it didn't stop until I released the pressure on the mount screws. I have a five cell 1700 in the tail. Also my servo arms and control horns are 1:1 ratio. Sorry for putting you to work. Joe

RE: Clevis Probs
 

np on the mounting screws. Again.. I have not ruled it out. I think it is a combo of things.. the servo not acting quite like it should and everything being a certain tightness given a certain throw ratio with large control surface. Other factors could include the operation of the servo in conjunction with the receiver with the above.. I have even heard that the metal clevis if it makes noise (metal on metal that is not tight).. can cause the servos to jitter... or even many of these servos together causing noise with each other. What it boils down to though is the servo not working like it should. I am sending it in and someone else can figure it out. We will see how good JR supports their product in the end.

Once again.. thanks everyone for their help.

RE: Clevis Probs
 

Well guys I have to preface what I am about to suggest with the fact that I have had NO experience with the JR stuff, until the current project that is on my table right now. A friend and I are assembling a BVM Kingcat for another person and we decided to go JR all the way since this is a $10K airplane and BVM pushes the use of JR stuff in their jets pretty hard, the radio set up is described using JR equipment so it was sort of a no brainer.

Something we noticed was during the elevator servo installation. The Kingcat uses a pair of 8411's on a split elevator, driven with a "Y" connector. The 8411's buzz and sing quite a bit, so much so that we thought we had done something wrong. The linkages are pretty tight but you certainly don't want ANY slop in a jets surfaces so we didn't think this was a problem.

Get this.....we were doing the set up with the horizontal stab off the plane and just out of curiosity I turned the whole thing up on edge and guess what......the buzzing stopped completely. As it turns out the 8411's will buzz with nothing more than the weight of the elevators pushing back on the servo arms. Turning the assembly from horizontal to vertical several times confirmed this to be the case, hold it flat and it sings like crazy, turn it up so the weight is off the servo and it's as quiet as can be.

I have never had a Futaba or a Hitech do this so I thought something was serviously wrong, it turned out to be a false alarm and quite normal. I think what I am trying to say here is that sometimes we expect a certain behavior based on what we are used to and see things that we think are problems that really aren't.

Not that a jittery servo isn't a problem but if they were just buzzing I would say turn it up and see what happens.

RE: Clevis Probs
 

Yeah.. some servo noise is expected. I can see this if I barely touch a control surface and it trys to force it to that perfect spot with high resolution and could see it in your case for sure with weight being that force. I would not worry about servo noise at all.

It is more like this. I turn everything on. It is sitting there (mine is actually quiet except my standard throttle servo) and I flick the rudder with my finger.. it start to shake back and forth VERY rapidly about 3/4". It will do this until I stop it by touching it or moving the stick... in fact.. Let it go for about 30 seconds one time (timed). I can take it back to center real slow and it will not do it.. flip the stick.. shake.. stop it... flick the rudder itself with my finger.. shake.. touch it to stop. I think that will paint the picture. It looks like it is having a seizure.

To make this happen.. it has to be high throws of 45 degrees or more, no slop, and large control surface (rudder on ucando.60). It I loosen the screw that holds in the servo arm itself.. it will not happen, if I go further out on the horn or further in on the servo arm.. does not happen. If I use it on another control surface.. does not happen.

The fact that a looser connection on the servo arm stops it made me agree with previous posts that I had the servo screws to tight or the hole not big enough. I made the hole quite large and the servo screws where they are not even touching the rubber... still happens. Even if this was the case.. I would consider this a defect. It shouldn't seizure just b/c there is no movement in the servo itself (in my opinion).

I think what is happening is there is a little play in the center of the thing (actually.. i know there is.. I can move some if sitting idle and in its center.. if i move my trims some.. no play at all) and when I flick it.. the servo forces it back to center from the right.. the left turn says.. no.. I want perfect center.. get back over there.. the right flicks it back and so on. I think it has to be a certain weight (large control surface) to be forced into the other side hard enough to get flicked back (but not too much weight b/c it would not get thrown hard enough).. a certain amount of force back in travel (high throws) to give it more speed.. and no movement in the servo (no slop) so that the force back is not absorbed enough to be thrown to the other side.

Kind of like when your wheels on your car are out of balance and you only feel it at certain rpm's of the tires.. just the right force and timing etc.

In my non-expert opinion I think the ds811's (at least the ones I have) have poor potentiometers.. possibly a defect in the ones I have... possibly in their design (hope not design.. I want this thing fixed!!)

RE: Clevis Probs
 

c016Y, That is exactly the symptoms only mine was on the elevators. Both sides would react the same way. They would sit an shake up and down all day if you did not stop it. I ended up having the linkage, on the furthest hole away from the servo center point and I believe slightly past that distance on the control horn, with the servo "mounting" screws slightly backed off and that did it. When you mentioned the "retaining" screw on the servo arm, one thing that I experienced was due to the supplied arms being too small and thin I opted for heavy duty arms, Dubro I believe, made for JR servos. Well, they sucked! They didn't come close to fitting snuggly on the armature even with the screw secure. There was play. I ended up getting servo arms right from JR. Have you tried swapping out all your servos to this position and they all do it? The LHS here would not have a problem with letting me try one from stock, providing he has one, to see if it still happens with a new one. There are such things as bad production runs and geography is in your favor as to picking one up from a different run. Good luck, Joe

RE: RE: Clevis Probs
 

Anybody know how to get this plane to do a tornado? Or know where I can get info on that?

RE: RE: Clevis Probs
 

hi all!!!

i build the ucd with saito 100 + apc 15X6 (is that the best prop for the plane?)
what is the best CG for the plane?
how much time the plane will fly with the original fuel tank?

RE: RE: Clevis Probs
 

Do not go beyond 6" CG. I would say 5 7/8"-6" would be optimal and maintain enough stablility to land it. Mine is at 6" and its tricky to land that way, put it at the recommended and the plane flies on rails but it wont 3D too well.


As far as the fuel tank capacity,I run the OS .91FS w/15x6APC Prop balls to the wall and I get 12 minutes easy. I have run as long as 16 hard minutes and landed on fumes.

UCD video
 

Joe Hunt flies the UCD ! http://63.246.139.60/mexcity-ucd.wmv

Which Prop?
 

In the process of building CREST UCD3D #2. I am going to power this one with a YS 1.10 ! What prop do you guys think I should run? I am considering the following:

APC 16x4wide
APC 17x6
Zinger 17x5

RE: Which Prop?
 

Yo, anybody got info on a tank that will fit in the .60 so that I don't have to cut the formers to mount it on the CG? Preferably a seamless one that will take the pressure of a YS110. It dosen't look like I have to remove a lot for the stock tank but, thought there might be an alternative. Appreciate it, Joe

RE: U Can Do 3D
 

I have a U Can Do 3D 60 and was wondering if anyone has ever used a 1.20 2-stroke on it?? I was thinking of using a GMS 1.20 with a pipe any ideas how this setup might work and what type of pipe to use?

RE: Which Prop?
 

deleted.. didnt' read.

RE: RE: Clevis Probs
 

ok im gonna re-do alot of my plane since the weather is gonna be crappy for a few more weeks.

Gonna re-do the control rods and want to see what other have on theirs


Joe I like your setup but I still want to see what other have on their planes. Would you guys mind posting pics of your tail sections to show the linkages etc?

Thanks

matt

RE: RE: Clevis Probs
 

Thanks for all the help guys, since I serve as diablo's pit crew, I would love any input you can give (pictures speak 1000s of words) I would much appreciate it! Hope to rejoin you pilots in the air as I have 3 planes on the bench at 90% done, probably going to pull a 3 maiden flight day on the first fly day of our season... crash pictures will be posted from both of us at 11:00. Thanks for all the great input and sharing your expertise and experience, you guys rule!

Lee

Carbon Fiber pushrod size for UCD 60
 

Hello,

I'm finishing assembly of my UCD 60! I decided to use carbon fiber rods, but do not know which size to use. I searched the forums and only found one recommendation - 5/32. Please advise, according to your experience is 5/32 rod is OK for UCD 60 or may be you are using another size? As I know the following diameters are available: 1/8, 5/32, 3/16, and .210".

thank you.
crank

RE: Carbon Fiber pushrod size for UCD 60
 

I used 1/8 carbon fiber on the ailerons and 5/32 on elevator (one side I used 4/40 rod 'cause was too short for the carbon fibre tube and titanium ends - from Central Hobbies) and went with pull/pull on the rudder (mounted servo on bottom of fuse as others did in previous posts). Works great for me. I'm flyin' with a now troublesome (2 deadsticks yesterday) Saito 1.00, 16x4 APC, S9202 servos.

RE: U Can Do 3D
 

How aggressive can your plane accelerate out of a hover ?
Do you think a bigger engine would of been better ?

RE: U Can Do 3D
 

Personally I like the ys1.10 for this plane. I went with the suggestion of other people in the forum on this one. If left default.. it will hover at 1/4 throttle and has endless verticle. I played with my radio to get more resolution on the hover so the bottom end movement did not move the servo as quickly as the high end. Works great.

The only thing you should watch for is reinforcing the firewall with that big engine with some triangle stock or something to give it more glue area. The warnings have been that be big engines will take the firewall off. (People have also said to reinforce the landing gear, area where the wings screws in, and, use different tail wheel.) I have not done this yet and I guess am just waiting to see if it really happens. If I was not so lazy.. I would take it apart and do this for safety, but, I am lazy. I just make sure I am behind it before I rev it up and only fly at my grandfathers land so I to not cut people heads off... ha.

One nice thing about the ys 1.10 beyond performance is that it is pumped and if you put your tank on the cg you don't have to get a cline regulator. I think that some of the saito's are pumped and I hear that they are easier to tune.. never used one and couldn't speak to that. I had to read up a little to tune the ys as it is different, but, now that I know how.. I would never change. It starts and runs awesome. I love this engine. Never sputters or hesitates.. after break-in has a GREAT low idle. Also.. the four stoke sounds awesome. Really makes a difference in how it feels to fly. Need to play with prop size still.. am being a little hard on the engine with a 16x4w and getting 9700rpms running pretty rich (max should be 9500).

Please note I am a novice, but, have read a lot and flown quite a bit the last 6 months. Can easily do knife edge spin, prop hang, flat spin and a lot of other cool/easy tricks with this combo (Speaking of.. I would like to know if anyone has pulled off a tornado with this plane!!! Can't seem to get it). Some of the experienced pilots may have a different opinion.. dunno.

RE: U-Can-Do-3D Video
 

What Engine are you using ?

RE: U-Can-Do-3D Video
 

going with a Saito FA-100