Now That I have discussed the basic layout and components of my landing gear retract system. I am going to prepare the wood rails that will hold the landing gear in place. This will consist of several steps that will comprise the proper installation of the landing gear rails.

Landing Gear Rails

The following video will show you how I modified my landing gear rails in preparation for the installation of the retracts. I felt that it needed a clearance slot to accomodate the air ports located on the side of each retract air cylinder, you will see how I modified this as well.

Pay close attention to the ways in which I modified the ribs to make room for the retracts. You will notice that I like to keep my sharp corners to a minimum and use a nice round sander to eliminate the sharp edges. Thanks for watching.

 

 

Steps to Prepare Landing Gear Rails for Retracts

Step 1

If you are installing landing gear that is driven by air, then you will need to install retracts in the wings and nose or tail. This means that there has to be a means to mount the gear to the airplane in a secure fashion. In the case of this model airplane, I am using plywood rails that will be epoxied into the wings of my rc plane and then drilled to accomodate the screws for the mouning plates of the retracts themselves.

The steps to prepare the rails are like any other part of your rc plane, measure the part and cut it to length. The landing gear rails for my scale rc airplane are no different. I am going to show you how I sanded, cut and made changes to the landing gear rails so that they would accomodate the robart retracts. 

As you may or may not see in the pictures below, the air ports on the sides of the air cylinders for the retracts are sticking out beyond the cylinder and will need some help. I fixed this problem by marking the rails where the air ports contacted them. I then proceeded to remove the material from the landing gear rails where I had just marked them.

Right and Left Landing Gear Retracts installed in their repsective wings in my rc airplane. I am marking with a pencil the area around the air ports and will remove this material from the landing gear rails.

 

Step 2

Next I cut out the marks I made on the landing gear rails and sanded them smooth with a homemade tubular sanding tool. This was a quick and easy step, but an important one when it came to creating the best scenario for installation and removal of the landing gear.

Using an X-Acto knife and tubular sander (basically a plastic pushrod with adhesive sprayed sand paper rolled around it) I finished up the slots that would give the air ports the clearance they need for installation.

 

Step 3

Now it was time to re-install the landing gear rails back in the wings and test the clearance slots for the air ports. If you are wondering about where to put your landing gear to make sure you have clearance, you will find that your building plans will show you an approximation of where to locate the landing gear in the wing.

You just need to make a visual check and verify that it is approximately in the right place. We are more concerned with the landing gear even installing without hitting those air ports at this point.

 

Step 4

With the air port clearance issue taken care of I wanted to finish up the issue of the clearance within the rib bays that the air cylinder would be going through when the gear is in place. This meant cutting and sanding the lightning holes in the rib to make room for the air cylinder.

As with most rc airplane construction, it is necessary to make adjustments to the parts, this does not mean that you did something wrong, it typically means that maybe a part was warped, or the building plans were off a little bit, or the die cut part was not aligned properly when it was punched out.

Whatever the case may be, be prepared to modify your rc airplane from the get go and you won't be caught off guard. It is part of building rc airplanes.

Ok, back to the modification of the rib to make room for the air cylinder, I placed the gear back in the wing and could see that the cylinder was not going to clear the hole in the rib, no problem though. I marked the rib where it would need to be cut and sanded and removed the retract and began cutting the rib with my x-acto knife. You can see this hacking in the picture below (also check the video for a more thorough  explanation)

After completeing the rough cuts of the opening in the rib, I finished up the job with my round sanding tool. This is a useful tool for getting in hard to reach areas and sanding a rough cut smooth.

It is always important to try and remove sharp corners for two reasons. One, you don't want to catch your self on it and get cut or a splinter. Two, you always eliminate stress points by rounding out any jagged or rough edges. No stress, means no failure.

Finally, I placed the landing gear robart retracts back in the wing of my bonanza rc plane wing and tested the fit. Surprise, everything fit well after the first try. Typically I must say that I usually have to cut, sand and test fit several times before I am satisifed with the fit, so don't think that this is typical of rc airplane builds. Always test fit and then take a little more off, then test again. Better safe than sorry right?

I am satisfied with the fit and can move on to epoxying the landing gear rails in place. This will be the next steps and will be included in my next post, epoxy those rails.

 

In the previous post I had finished setting up the landing gear rails to prepare them for gluing. In this post I will be epoxying the landing gear rails into the wing of my bonanza rc airplane. Whenever you are going to glue any part in your rc model plane you need to be very sure that you have made everything fit and any parts that need to be installed will go in easily before you permanately glue in your parts.

Video: Using Epoxy To Glue Landing Gear Rails Plus a Bonus Tip on How To Remove Epoxy.

Let's Glue Those Landing Gear Rails Already

Step 1

As with any rc airplane project, I always clean up my building area before starting on the next component, this removes clutter and helps me think more clearly. You can choose to follow this tip if you like, it's up to you. I know for me if I clean up before the next steps, I can really see the overall picture better too, but that is just me.

When it comes to using epoxy, you want to make sure, really sure that the rc airplane part you are about to glue has been checked and re-checked. Now that my work area is clean, I went and got my epoxy for this job.

I was using 5 minute epoxy, but I really should have used 15 minute to give myself more time. There is no rush and you should give yourself plenty of time when it comes to epoxy.

Now to get gluing! I use a piece of wax paper and begin pouring out equal amounts of the resin and hardener (if you are not familiar with epoxy, it consists of 2 components, a resin and a hardener, when mixed together it starts a chemical reaction and the glue begins to get warm and the curing process has begun).

In most cases, most newbie's will mix too much epoxy and waste it. Instead, I always mix a smaller amount, and if I need more, it takes no time to mix another batch. This is also a good reason to use 15 or even 30 minute epoxy, you will have more time to figure it all out and not feel rushed.

Step 2

Now that the glue is mixed, take the forward landing gear rail and only apply glue to the points where it will contact the ribs. Try not to apply too much glue so that is does not drip.

You can use a cheap acid mixing brush to apply epoxy, it works quite well. You can get these at auto parts stores.

After the glue is applied, it is time to place the landing gear rail back in the wing ribs exactly as it was removed. I like to mark my parts so that I know where they went and I don't have to think about it (a simple top or a few marks on one side is all it takes).

I always make sure that the joints of my glued parts look completely covered in glue before I move on to the next gluing job

Satisfied with the first landing gear rail, I apply glue to the next landing gear rail where it too will touch the ribs in the wing, and set it in place. I check it over to make sure all joints are covered with glue. Now is a good time to clean up any excess glue that may have started oozing down the side of the ribs.

I use a piece of wax paper to clean up all the excess glue. Try to remove as much extra glue as you can, it does nothing for strength, it will only add needless weight to your finished model, which we do not want.

Step 3

Before the glue sets, I clamp all the rails in place. I also add a piece of wax paper between my clamp and the glued part. Nothing worse than gluing your clamps to your parts and trying to pry them apart. Now all that is left to do is wait for the glue to dry.

I like to wait 24 hours before I remove my clamps and start working on the rc airplane parts that I just glued. This is because epoxy does take time to fully cure. Yes, it dries in about 15 to 30 minutes, but the full cure time really is 12 to 24 hours, depending on your humidity level.

Step 4

Well, the glue has dried and I can remove the clamps from the landing gear rails. It is always a pleasure to see my rc airplane come together and see all the parts work together to create a working model. Thanks to the wax paper that I put between the clamps and the glued parts, they come off nice and easy.

You can see in the pictures below that the wings landing gear rails are now glued in place and all that is left to finish the rails is a little sanding to make them flush with the ribs. I use a homemade sanding block, it was made from a scrap piece of 1/4 inch plywwod and I use spray on adhesive with the sand paper to make it stick (I used 100 grit to sand the rails flush).