RE: COMP-ARF A-4 BUILD
 

David,
Could you fix the front fork and have that whole assembly pivot about the main strut by having the inner leg rotate, controlled at the top?

RE: COMP-ARF A-4 BUILD
 

Sean,

In a word, "No". Unless one has access to a machine shop and the knowledge to remfg the entire strut. Intairco, In their desire to make this gear as scale as possible, constructed it much like the full scale, which makes it very difficult to modify.

Scott,

"Picky, picky":)

David S

RE: COMP-ARF A-4 BUILD
 

maybe we could get together and see if we could get another manufacturor to make us a nose gear.
Turbo makes the gear for my F5 and the strut also extends for takeoff. It has a servo up top for steering.
I would need two myself.
Anyone else interested? probably would need a minimum order and wouldnt be cheap.
Scott

RE: COMP-ARF A-4 BUILD
 

What about the stowing of the steering servo lead... It would be a BIG issue if it was damaged, cut, frayed etc.

RE: COMP-ARF A-4 BUILD
 

goes up this tough cord to protect it.
scott

RE: COMP-ARF A-4 BUILD
 

Tested the smaller servos... won't work under load. Worked on oily Hydraulic system tonight... mushy.. I'm back to the independent braking deal..

RE: COMP-ARF A-4 BUILD
 

I would be interested Scott. I'm under the gun with mine for JWM.

Andy

RE: COMP-ARF A-4 BUILD
 

Fellow A-4 lovers !

From my point of view everything different from the original hyd. layout is pure ugly - I am sorry to say !

This bird cost a fortune and I have no intention to spent a dime to reconstruct a 4000 EUR undercarriage.

We are not going to make it work - CARF has to do this !!

I really dont care if Intario has problems with it - I paid CARF for the entire kit.

Therefore I suggest instead we all spend alot of money on modification we simply all of us take a plane to Germany and pay our friends a visit to get it all sorted out !

It is a pity such a lovely plane are only going to be hangar queens because none of us feel really sure about the plane due to lack of info, settings and so on !

Just my point because I am getting more and more..

Peter

RE: COMP-ARF A-4 BUILD
 

Maybe we can use this:

[youtube]http://www.youtube.com/watch?v=vvaYTVBHHYU&feature=player_embedded[/youtube]

RE: COMP-ARF A-4 BUILD
 

I'm looking into some more sophisticated hydraulic solutions. IE, using a hydraulic pump and valve system to actuate the hydraulics instead of a servo. I have been doing research in the "Earth mover" RC group and found a bunch of info related to this. Here is a company that makes hydraulic retracts. I believe we can utilize this system to actuate our hydraulic stearing cylinder. I've found all kinds of different cylinders to. Here are the links:

http://morpower.net16.net/index.php?...tegory&path=59

http://www.robbe.de/zubehoer-ersatzt...aulik.html?p=1

http://www.gardentrucking.com/produc...esort=1&max=10

Electric cylinders:
http://www.cti-modellbau.de/index.php/cat/c32_.html

This one under Hydraulic (lower page):
http://www.leimbach-modellbau.de/

Well, this is a start. I had no idea how incredible and technical the RC truck and Construction gang was:

http://rctruckandconstruction.com/forumdisplay.php?f=7

RE: COMP-ARF A-4 BUILD
 

Wow, talk about lots to consider - retracts, extends, springs, steers.

Thinking outside the square (because inside the square has run out of solutions)
would a closed loop system using 2 cables work using inner & outer cables, with a
double sided steering arm.

Think motorcycle front brake, forks extend & compress, steers from side to side but
you still have plenty of feel through the brake handle. - John.

RE: COMP-ARF A-4 BUILD
 

Here is a pick of the recommended system (I think). I say this because there is no information available from the factory other than pictures. As it stands with this open type system air bleeds by the cylinders. Currently the 8711 servo strains itself actuating this system as it's set up. I've tried enclosing the open ports on the servo cylinders and it gets even harder to move.

RE: COMP-ARF A-4 BUILD
 

Andy,
I think at some point it was changed to one master and one slave.
Scott

RE: COMP-ARF A-4 BUILD
 

Hey Scott, Where did you see that? Is that how you set yours up?

RE: COMP-ARF A-4 BUILD
 

I cant recall where but it does actually work better. a fellow member on here actually suggested it as well. Kirk J. He had told me to sumberse the hole system under oil and bleed all air out and hook up lines. think David said this as well. I did that and it worked great
I felt like I had it working really good this way but I left it sitting up for a few months and came back too it to find that there was air in the line again. I cant imagine pulling this out all the time to bleed.
making it a more conventional steering sounds way better!!
My F5 nose gear pumps and steers perfect.

RE: COMP-ARF A-4 BUILD
 

You guys are going through exactly the scenario that many of us went through with the Mig 29. Quite simply the hydraulics did NOT work as they should, they were not airworthy, and yes, I even saw Wolfgang Kluhr with a collapsed gear in Thailand. Geitz, of course, said it was all OUR fault and that I knew nothing about hydraulics (wrong, very wrong Andreas) Even though I am one of the few to get a Mig 29 flying (with the help of the Omega hydraulic system having ditched the original) he still blames me for damaging his sales ! My Mig will fly again next year with further modifications to the hydraulics. However C-ARF will sell us the new hyd sysyem, which does work, only if we pay full price, he won't even supply just the self locking rams. Customer support at its lowest ebb !

I know Peter Agnew of Intairco very well and if C-ARF and AG is blaming Peter for his troubles he is wide of the mark. Peter's own products always work and my understanding is that he produced the gear to CARF's design.

I guess a lot of A4s will join the Mig 29s gathering dust.

Makes my blood boil to think of it.

Regards,

David.

RE: COMP-ARF A-4 BUILD
 

Right now I would pay $2,000.00 for a solution (I'll start a $1k lol as shown on the other thread!). I will find one. It's just sad that they have let this project rot all the while they are still selling the kit when they know it won't work...

RE: COMP-ARF A-4 BUILD
 

The truth is, I never had plans to enter this jet in any type of scale competition, I just love the jet. That being said, I would have preferred to keep the scale appearance of the nose gear steering. I have now taxi tested my direct servo modification and it works perfectly. So at this stage, I've owned this jet now for over two years and I want to see it fly. Time to cut my loss and at least have a flying jet instead of a static model. Once I taxi this jet away from me, I won't even be able to see the nose servo, and once it takes off & I retract the gear, no one else will be able to see it either. That's just going to have to be good enough. If at a later date someone else finds a suitable fix, then maybe I'll switch mine over.

Now the question is whether or not there are any flight deficiencies lurking that I don't know about. Comp ARF lost their first model to flutter, I believe, and I'm not sure if this kit has the modification which solved that issue, and Andreas has not been able to provide me with that info either. All and all, this has been a disappointing adventure so far, I can only hope the flights will even things out a bit.

David S

RE: COMP-ARF A-4 BUILD
 

Good Lord they have the gall to keep your deposit and they aren't even shipping a jet that can operate reliably due to their engineering deficiency? I think you should consider your options when it comes to giving up on 1000 bucks due to their failure to deliver and your "good faith" demonstrable loss of confidence in the product due to a failure to perform to the marketed intent. It's not like you walked away because you wanted to buy a set of rollerblades and knee pads instead, is it!!! (well you got the knee pads but I'd send that back to them with a letter from an attorney).


David, good work on your temp solution. I'm sure a permanent solution will be much more "attainable" as you'll have the patience for something that looks the part once you get some stick time on the jet. From the many flights I've seen of this jet in person, I think your hard work will be worth it but no doubt shame on CARF for not supporting any of you who pay the bills and promote their product by your own successful projects.

RE: COMP-ARF A-4 BUILD
 

Andy,

Actually, that is the setup I was thinking might work. Using larger cylinders for the drive side gives you some "mechanical advantage." The system is still filled with fluid in the closed side of the system, correct? If not, then I can see why it would not work - it has to have fluid in it, air is too compressible to move the steering cylinder reliably. Even with fluid in the system,it shouldn't be able to get by the drive cylinder's O-rings and leak out the open side. If it does. then the cylinders are *really* crappy and should be replaced.

You are right, if you plug the "free" side of the drive cylinders than you are alternately creating a vacuum or pressure that will oppose the movement of the cylinders by the servo. What you might be able to do is tie the "free side" of the drive cylinders together. That way, as one is moving forward, then it is creating a vacuum that is helping the other to move aft. You might even be able to fill the back side of the cylinders with fluid too before you tie them together.

With fluid in the system, all of the air blead out, and an 8611 or 8711 servo driving it, I can't see a reason why this system won't work - it apparently does work on the Skymaster A-4...

Bob

RE: COMP-ARF A-4 BUILD
 

Right on Dave!!!!! Scotty

RE: COMP-ARF A-4 BUILD
 

I bet if you submerge the entire system in oil to bleed it, and then run a line between the two open ports in your picture (make sure one cylinder is retracted and the other extended) that would help the servo move the two master cylinders

RE: COMP-ARF A-4 BUILD
 

That may work. I need to get a new cylinder next to the wheel because it leaks oil. More time wasted.

RE: COMP-ARF A-4 BUILD
 

Out of curiosity, how much of a stroke do you need for the actual steering cylinder, and how much room do you have to work with?.. 1"?

RE: COMP-ARF A-4 BUILD
 

And...one question, not ¡s possible use one only piston for rudder ? using the two nipples, if you place the piston in the midle position you can control the rudder.

You can do this as well?

BR from Spain.

Carlos Márquez
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http://cmjets.blogspot.com.es/