kschultzkes

Photo 3: Modified Wheel Well for Robart 618

kschultzkes

Photo 3. Gear UP before painting.

kschultzkes

Last Photo of Robart Retract Kit for AT-Texan Axle which needs to be shortened in order to fit properly into wheel well. KEN

kschultzkes

In my post #773 I know Tom's boxes will be of value....what I meant was I hope the thread with photos of the Retract installation will be of value.  KEN

jet22b

Ken,
Your setup looks great!!! You did not waste your time posting the pictures. Like I said before, I do have a set of Tom's boxes and they are good for me. I remember on the third flight of my AT-6, I came in for a smooth slow landing and when the plane touch down, both gear just rip out of the wings and did major damage, where I had to buy a new set of wings. And as you well know, grass field are hard on retracts!!! Lets us know how the maiden flight goes!!!
Sonny
aka,
Jet22b

Cougar429

My Feedback: (3)

Looks like a good fit and the struts may help a lot. I'll hopefully be testing mine soon.

As for air retracts, they have their good and bad points. The good is there is no worry of mechanical binding overstressing the servo or linkage and a much easier routing out to the unit(s). You did not have the bother of locating a servo and then ensuring free movement of the rod and linkage.

The bad is the need to recharge the air system often, monitor the system to ensure you had enough for each flight and the too common problem of leaks, (with the requirement to connect and unplug the lines every time the wing was installed or unbolted for shipping). With an air UP/DOWN loss of pressure can prevent gear extension. That's why it was better to have spring DOWN setups as a loss of pressure meant the gear would down and lock automatically.

One other issue was the need for restrictors if you wanted a more scale sequence. A direct setup often had the gear retract or extend so fast it was almost invisible.

kschultzkes

Guys. Thanks for the replies. What's also nice about the Robart system is that there's a functional built in shock absorber. The wheels can move up about 1/2" within the system. I'm also using a Magnum .91 4 stroke in the Texan.

I'm going to try to fabricate a hatch cover for the struts as seen in the full scale plane photos. I intend to look at the AT-6 actual plans to see the true dimensions and scale the hatches down.

It will probably be awhile to fly my maiden flight (probably later this summer). Although I will probably taxi her out before flying. I've graduated from several trainers and am now flying a J-3 Cub (Goldberg KIT). I intend to learn how to fly my ARF Stinger II and will use an experienced warbird instructor for the maiden flights of the AT-6 when I think I'm ready.

Another question...Sonny, I see in past threads you balanced your AT-6 at 4.055 in. with a balancing system. If you notice, the wing slopes slightly forward from the fusalage to the wing joiner. The balancing system you used has the balancing points closer to the fusalage than at the joiner. Since the plans call for 4.25 in. back from the joiner as the balancing points, it looks as if the 4.25 and 4.055 may be equivalent horizontal points on the wing. KEN Denver RC Eagles

Cougar429

My Feedback: (3)

I can't remember the dimensions and had to look it up in the TF instructions. They specify 4 1/4" back from the leading edge at Rib #4, which is at the center/outer wing junction. This is identical to yours. I believe this places it right over the main spar.

kschultzkes

If you look at photo in post #777 you will see what I'm talking about in the above post #782. Above and out from the wheel well, the leading edge slopes forward to the joiner.  KEN Denver RC Eagles.

kschultzkes

Yes, this is why the measurement at the joiner of 4 1/4 is equivalent to the measurement of 4.055 on the fusalage side of the joiner using the balancing system as noted by Sonny in prior threads. Ken Denver RC Eagles

Cougar429

My Feedback: (3)

On my kit-built that front edge is straight. The instructions specify checking aft from the point AT THE JOINER. Ignore the rest of that leading edge and work immediately next to the joiner cover.

kschultzkes

Yes, I did that and it is balanced. Thanks again. KEN Denver RC Eagles

jet22b

Ken,
To tell you the truth. my AT-6 is a tad nose heavy!! I set up all my planes a tad nose heavy. Like I said in my other post, I use the Great Plane CG Machine to balance her. So far the CG has work for me. I also like to do a balance with a full tank of fuel, just to see how far it move before or behind the manual CG setting.
I may have to pickup one more before Top Flite stop making them. She is on the charger as I type this post, for a day of flying tomorrow!!!
Have a good weekend everyone!!!
Sonny
aka
jet22b

kschultzkes

Have a great day.

RiverLarry

OK tell me about Toms box and how do I get it R/L

kschultzkes

Check out earlier threads...p 30. Basically he designed metal boxes that house the AT-6 RETRACT olastic assembly. Many members have found it prevents damage to the hiusing and wings on landing. Well worth the th $38. You can contact tom via this site. Ken

jet22b

RiverLarry;
Send TomTreese a PM through this thread, or he may see your post and answer you here. I have a set and I and very happy with them. And like ken said, they are well worth the money!!
Sonny
aka
jet22b

TomTreese

My Feedback: (1)

You can contact me at; [email protected].

Capt Easy

It's been seven months and a couple more airplanes added to the hanger since my last visit. However, my SNJ is back on the table with plans to finally complete it.

I withdrew my original idea of combining a rudder pull-pull system with the tailwheel and installed a simple horn and single 2-56 connecting rod .

The tailwheel has been mounted in a scale location using a modified Du-Bro assembly with a brass arm soldered to the strut. This was attached to a Sullivan Semi-Flexible connector running forward to the rudder servo arm under the front cockpit. The plastic tailwheel assembly is secured with two 4-40 hex head bolts to blind nuts epoxied to the balsa hatch. In addition, 3/16" lengths of fuel tube was slid over the bolts between the top of the plastic base and the balsa hatch to provide some shock absorbsion. I added a spring to the strut also just to add interest and function.

That's it for now....next I want to improve the main gear with something more reliable even though I have Tom Treeses' metal plates already installed.

Dick

Capt Easy

Anyone left out there.....?

DGUY

My Feedback: (9)

Like what you did with the tail wheel.

Capt Easy

Hey thanks DGUY - I think it came out pretty good....we'll see more after some taxi testing. My next mod includes cutting out a cowl ring from light ply to epoxy inside the cowl. Magnets and an indexing screw will then attach it to the firewall.....easier install and removal and looks better too.
I did a preliminary CG check earlier today and was sorry to see how tail heavy it is.

Capt Easy

Hey thanks DGUY - I think it came out pretty good....we'll see more after some taxi testing. My next mod includes cutting out a cowl ring from light ply to epoxy inside the cowl. Magnets and an indexing screw will then attach it to the firewall.....easier install and removal and looks better too.
I did a preliminary CG check earlier today and was sorry to see how tail heavy it is.

DGUY

My Feedback: (9)

Capt E I am trying to figure out a way to get the exhaust out the scale location. I am running a an OS fs 91. Got any ideas? I thought of using silicone tubing running of the 90degree exhaust manifold.
Derrick

Capt Easy

Derrick, Wish I could be of help but I converted mine to EP.....if there's anything I can do I'd be happy to help though.