Retract Trouble

[whansen]

I did a search here for “retract trouble” and did not find much in the way of answers to my questions so I thought I would start a thread to discuss what others have successfully done to make their retractable landing gear function properly.
I have assembled a .40 Kyosho Spitfire and have used retracts that come with the kit and also have tried my hand at installing .40 size retracts from Thunder Tiger. These are both the direct to servo / non-air type. In each case I have had 2 reoccurring problems.

1) The axles don’t seem to stay in the position I have mounted them
2) I have tracking problems during taxi and take off.

My flawed technique follows: I file the area of the "leg" that I attach the axle bolt to so that it won’t slip and I use lock tight. I have found that the axle still gets tweaked after a few landings and eventually is very difficult to steer on the ground.

I have included some photos of my set up.

Does anyone have any suggestions on how to make the axle remain where it is placed? What is the preferred toe out in order to have the aircraft taxi well?

Thanks Much! I have learned quite a bit here in theses forums!
Warren

[El Pe]

Sorry to hear about the problem, but it is not uncommon. If you could change the wire to a pre-bent type, you should do it. It is a lot to expect of a little set screw to bear the landing G's and not give up sooner or later. Rather than filing a flat spot on the leg, you might try the cut-off wheel in a dremel rotary tool to grind a very small but flat cut where you have been filing. Small set screws seem to like that better. Another possibility if the hub is steel instead of aluminum, is to silver solder the hub to the wire. If you mis-align the solder job, you can always fix it where the leg goes into the retract.

We had a very similar problem with lousy tracking on roll-out. It turned out that it wasn't then gear at all, but the wheels. They were wobbling on the hubs. I notice you have foam wheels, so they may be the cause in this size aircraft. Try changing them to rubber or a very substantial foam and see if that fixes the problem.
Good luck
Lee

[BRIT_BULLDOG]

I also grind flats on anything that a set screw goes into :)

Just a suggestion, could you not do same on other end of leg where it is fixed into holder? will take some aligning though!

I keep wheels dead in line or very slight toe out.

Definetly no toe in

[wellington53]

Brit has suggested what I have already done with my Kyosho Spit. I can see in the last picture what your problem is where you have filed a flat but at an angle so that it does'nt matter how tight it is, it's going to get loose. What I did on mine is use my dremmel with the grindstone and grind a flat just where both screws touch the leg, not all the way to the end. PM me if you want a picture Warren.

[whansen]

Very good ideas! Thanks s lot. The dremel will help for sure and I will lose most of the toe out there.

I think the wheels are suspect as well. I will replace them with rubber as suggested. Do you guys have any tips for drilling out the hub to the right size. I dont have a drill press and I hold the wheel by hand and use a hand drill. There must be some slop from that and I bet there is a better drilling technique.

Making a bend without the use of a separate axel is an excellent idea. Any ideas on where to find the raw material for that? Is there a source for just the "leg"?
Thanks Much! Warren

[BRIT_BULLDOG]

Are the struts long enough on the kit to make a bend?

[wellington53]

Warren, I can't seem to upload for a PM so it's it's here. I drill out my hubs the same way as you, Just go slowly and make sure the bit is sharp. Before you start to pull out your stock retracts have another go at grinding because as far as bending a new axle goes this stuff is hard and can snap which will get you more frustrated.
Glenn.

[Heather]

I have a Kyosho BF109 that I fitted Great Planes Retracts into. The biggest improvement in ground handling was to replace the foam wheels with rubber/plastic ones that do not compress as much.

Still needs almost full right rudder on takeoff but that is normal model like this but at least it does not nose over on landing anymore!

Heather

[whansen]

Thanks for all the tips. I am going into the shop tonight and will try what has been suggested here. The struts are not long enough to bend to eliminate the axle so I will switch to the rubber wheels and grind a flat spot on the strut. I am going to try to make a channel on the strut to stop as much slop as possible.

[whansen]

I used a dremel with a narrow grinding tip to make a flat notch, more like a hole in the strut and the axle locked in like never before. There was a little gap where the strut met the axle so I coated the strut end with epoxy, attached the axle and used lock tight on the set screw and let it set up over night.

[jismail]

I am trying to install retracts on an AT6 I have (GWS) I purchased the Great Planes mechanical retracts and a Waypoint v-150mgr retract metal gear servo made just for retracts. SPECS: weight .59oz, torque 4.8v 52 oz/in, travel 125 degrees.

The issue I am having is that no matter what location I put the push rods on, the server travels further than necessary and rips my servo out of the socket I made in the foam once it reaches the end of the rod length, but is still trying to travel further.

My radio's 'Gear up' channel has a travel limits setting on it, but this servo appears to be an all or nothing movement and doesnt seem to allow for limiting its travel.

Am I doing something wrong? What servo do the rest of you use? Is a standard servo made for a wing/rudder okay to use? Did I waste my money getting a "special" servo?

Thanks in advance for any help.....

[wellington53]

No you did'nt waste your money at all, dedicated retract servo's are like the one you have is called non proportional (all or nothing) A standard servo can be a problem in that it is still working in either direcion and drain the battery or burn out. Retract servo's shut off after they fully travel in either direction. To limmit the servo travel for your rods you want to place the linkages for the rods to the inner holes on the servo arm so there's less travel.
Hope this helps.

[whansen]

I let everything set up and harden for a few days. I am still waiting for the rubber wheels to arrive but I installed a set of larger foam wheels that did not need to be drilled out. I taxied around today and there is no tracking and it's ROCK SOLID! Thanks for all the tips. I'll fly her tomorrow.
Thanks Much!
Warren

[ElectRick]

Two things I've always done to eliminate these types of issues:

First, silver solder the axle in place--once you have it properly adjusted for height and toe in. Don't worry about this being a more permanent fix--because why would you need to ever adjust it again after setting it correctly?

A little set screw just isn't up to the task of holding against the twisting load that a landing impact puts on the axle. Just clean and flux the wire well, silver solder the axle in place, and it will stay put forever. I've done it many times, and this works perfectly.

Second, put a little TOE IN into each axle. TOE IN--not TOE OUT, as has been stated earlier. Toe in is where the wheels point slightly towards each other at the front. One degree or so (just enough to see that it's there) for each axle is all you need. Toe out will cause the plane to want to ground loop. Toe in provides greater straight line stability.

Rick

[whansen]

Thanks again everyone! I flew today and had 3 successful landings and did not have to adjust the landing gear at all. It taxied perfectly all day and retracted into the wing as designed.

Rick, I like your idea of using silver solder. Is that the kind used for soldering wires or the heavier stuff used in plumbing?
Thanks
Warren