acdii

I used a pull pull cable system for the steering controls. When extended, just the right amount of tension, when retracted allows the rudder servo to move the rudder without the tail wheel moving, and was able to use only one servo for both. Note though this is on the 60 size, not the GS one.

rt3232

My Feedback: (6)

tho I did not put doors on my tail wheel I did use cable pull/pull and in about 100 flights have never had a problem with the retract or coming down.
Maybe I have just been lucky

cheers Bob T

acdii

I can get some pics if anyone is interested. Should work out the same with the GS.

Chris Nicastro

My Feedback: (3)

I used ball links on the gear and the door. This is just like full scale as the gear retracts it pulls the doors closed. Same as on a P-51 too for example. I made right angle brass strips and drilled holes for screws and the pivot ball stud. This assembly is screwed to the retract. Another one is attached to the door with epoxy.
You can adjust the length of the links to set the timing of the doors and how tightly they close.
This system works perfectly and my buddy copied it to his big P-51 too.

Chris Nicastro

My Feedback: (3)

You can see it's very simple to do

Here it is on a P-51

Nordicz

My Feedback: (7)

Chris,

I've done that on my P-47 and like how it works. I think I'll do the same on the corsair.

Z

acdii

Nice idea, I think I can use a modified version on the B-25. The doors on that are closed all the time and only open during a cycling. I can make a bar that attached to the servo and then ball links to the doors.

Auburn02

My Feedback: (1)

I was actually talking about the steering for the tailwheel and not the doors, but this is all going to be hugely helpful when it comes time for me to do the doors too!

I do see in Chris' picture he just used a pull-pull cable looped through the steering arm. I think that's probably easiest. I was hoping to put a threaded end on one end or the other for easier line adjustments, and there's currently no room to do it at the servo because of the former behind the servo tray, but I think I can make room by turning the servo around.

acdii

Maybe these can give you a starting point. This is in my 60 size Corsair. What I did was take a standard servo arm and anchored it to the inside, then run cables from it to the tail gear steering arms, crossing them inside to match the rudder direction. I then used a ball link to connect that arm to the rudder servo on the same side as the rudder link, one hole in from the outside where the rudder connects. Since I used the servos in another build, they were only used for setup, I dont have pics of the completed link setup. Sorry about the first one being blurred, didn't notice until it was already uploaded, but you can see how the cables are slack, allowing the arm to move freely, then when the gear is down they tighten up allowing the wheel to move. I need to get back to this plane some day. The paint on it came out really nice, but a bit too glossy, and not 100% covered, some areas are mottled, so I am going to wet sand it and apply a coat of automotive clear flat instead. I still have to finish painting the colors on the bottom of the wing too, then I can finish the assembly.

Auburn02

My Feedback: (1)

That's great, thanks. Pretty nifty about anchoring a servo arm and then driving it with a separate link instead of running the cables back to the servo itself. I was planning to use a separate steering and rudder servo, but that might work too. It's so hard to read this thread at work and not be able to walk over and look at my plane on the bench while I have my head full of ideas.

acdii

I know what you mean. Doing the same with my B-25, got a lot of ideas in my head, then when I get down there,I lose them all as I work on it since I am not yet to the point in the build to where I can do what I had in my head. argh.

Chris Nicastro

My Feedback: (3)

I put that adjustment at the servo end so it's very easy to get to.

Chris Nicastro

My Feedback: (3)

One other thing you guys can look into is Conditional Mixing. If your radio has the ability then you can set the tail wheel steering servo to turn off when the retract cycle is engaged. When the retracts are extended the servo works again. This helps save power and any chance of strain or fouling of the control wires should any of that be an issue.
I do this on the YA P-38 for the nose gear because of the wires.

Auburn02

My Feedback: (1)

I always do this on anything with a retracting nose or tailwheel (where steering is on its own servo) - good suggestion.

Not to stray this topic, but any pics or link to your P-38? Have you flown it?

Chris Nicastro

My Feedback: (3)

Yep it has a few flights on it now. Twin DLE 35RA's do very well. I'm going to add rivet detail and finish the graphics soon.

Auburn02

My Feedback: (1)

Very nice Chris.

Almost hinging time. Just have the middle flap for the left wing to build. Still undecided on how I'll hinge them and then how I'll drive them between either the internal linkage or external like the ailerons. I'll probably move on to shaping wingtips as soon as I finish building the last flap and save the hinging nightmare for later.

ibow24

My Feedback: (10)

Glue those flaps in place and forget about making them operate. It will save about a year of pulling your hair out

I used some scap balsa and made a mock up of the wing trailing edge and flaps leading edge and used that to make different test holes for flap operation. (actually I made several mock up til I got it right).
From your pics it looks like you do nice work.. You'll get it right.

ctflyboy

My Feedback: (3)

To All,
I"ll say it again, if those Robarts hinges are not lined perfectly they will bind and will not work (they didn't for me) and I tried them twice you know filling up those holes with balsa dowels & epoxy to me it was very frustrating and not worth the aggravation,thats why I went with the Dubro heavy duty large scale hinges, installed them where the Robarts would go and they work flawlessly. (JUST MY 2 CENTS WORTH)

Auburn02

My Feedback: (1)

I'm still debating ordering those Tamjets hinges too, but I probably should have taken that into account when I put in the hinge blocks if I'm going to use them. And quite honestly, my wing was built and sheeted most of the way before I got it, so I'm only assuming the first builder put the hinge blocks in the correct locations...

http://www.tamjets.com/OSCnew/produc...roducts_id=122

ibow24

My Feedback: (10)

George,
Can you show a pic of those hinges in your flaps? Maybe I'm missing something but I don't see how a flat hinge would make it easier on that center section of flaps.
Thanks

BobH

My Feedback: (2)

FYI Robart makes a jig for it's hinge points. It really helps center the hinge point on the Trailing Edge.

http://www3.towerhobbies.com/cgi-bin...FcWKswod6wYEPQ

acdii

This was covered I think on the last page. The wing tip on the Corsair isn't centered, but offset a bit, so that centering guide doesn't help. The best method I found is to draw a line from tip to center, and you will find it isn't centered all the way, but angled, so I drill the holes down the line, and use a dowel that has been tapered and sharpened to a point, and use that to mark where to drill the wing. This prevents binding that occurs if you were to center the hinge line instead.

Nordicz

My Feedback: (7)

I'm a going to be a slow poke on progress for a while due to other obligations in the next few months but a simple thing is done. Control surfaces have been shaped and hinged. Ailerons have been already done.


Z

BobH

My Feedback: (2)

acdii,
the jig centers the hinge between the top and bottom surface. If you have a Gull wing for example.. Each part of the Gull will have its own trailing edge. The jig just centers each section as necessary. The wing top too has its own center. Should work there as well ..

acdii

The reason it doesn't work for the Corsair aileron is the middle hinge is not centered on the trailing edge, but is offset. If you put a straight edge on the outer hinges you will see the middle one sits higher. If you center all 3 then the aileron binds. I think on the prior page this was discussed with another member who ran into this as well, and I too suggested the Robarts guide, then remembered, wont work for the Corsair aileron.