Spychalla Aircraft

My Feedback: (34)

1/5th Scale Bate Wildcat builder Charlie Morton of PA has alerted me to something. He said his chains on the ROBART gear are longer than print. Until now I just went to print on the gear mounts and never put the chains on. From what was described I can see that the chains are longer but there are other issues that create binding when the rack and pinion are mounted on a flat former.

I have decided to change the gear mount formers on my Wildcat kits to reduce the binding and improve the location of the rack and pinion. I know the system works when it is all mounted per the ROBART print on a flat former, but I think this is going to be much better. If you are building a Wildcat you may want to consider making this adaptation.

See the attached photos. The cut-out plate starts 1" from the top of the former and it is 7" tall by 2.5" wide. It has a bonded overlap area of 1/2" on both the top and bottom. It is angled at about 7 degrees. The chains move really smooth now. No binding.

Doug Imes has over 50 flights on his ROBART gear now and says that the chains must be really tight or they will jump off the sprockets and skip a tooth. This can cause one gear strut not to lock down on landing and make for a hazardous situation, so maintaining tight chains is critical. He has had to land with only one gear locked down on two occasions. It amounts to making a one wheel landing which is not easy.

Leo

rongreg13

My Feedback: (129)

Any idea what Charlie's solution was to the oversized chains? Did he modify the setup or get new chains from Robart?

Spychalla Aircraft

My Feedback: (34)

Charlie gave me indication that he was just going to move the rack and pinion assembly down in order to take up the slack in the chains. That will solve the problem related to length but it will not remedy the 7 degredd twist that the chains experince. He is not on e-mail or the internet, so I have no easy way of communicating with him other than to call.

Ron, what do you plan on doing?

Leo

rongreg13

My Feedback: (129)

I still haven't decided. I guess I will have to set things up to see the situation with the stock per plan layout and decide if it is acceptable or if I need to perform the mod. If possible, I'm going to try the flat setup, but if it looks like there is a good chance of binding on mine, then I'll go ahead and make the big cut. I'm most concerned about making the cut cleanly (and easily) without damaging anything in the fiberglass fuse. My Wildcat is still 3rd in line in my workshop, so I've only been piddling around with it so far and have only installed the tail gear just to see how it would fit, so I'm not in a hurry and will probably be taking my time on this one!