Main Gear Beef Up

Date:  05-11-2019

Number of Hours:  6

Manual Reference:

Time for the ‘other side’ reinforcement plate.

What is the ‘cost’ of this upgrade? The benefits are less likely main gear failure, particularly at higher MAUW. It is more weight at the rear end too, exactly what we don’t want.  1lb 9.6ozs is the estimated all up weight penalty.

This is significant. I am doing this because I will be a heavy Long-EZ with full fuel, if I have to land back with 550 liters on board, thats 396kg or 871lbs. I could be in the 2000lb range all up.  That would be exception circumstances, after a long flight of course fuel is burnt off. Then there is the unexpected pothole consideration too. I have set the MAUW of the plane at 995kg or 2180lbs in the paperwork which I can as the manufacturer.

The side had some challenging bolts to get out. The one above took 2 hours to remove.

Finally I got the plate blank fitted.

Again the blind hole matching trick worked very well.

After a lot of clean up and plenty of flox in the bolt holes I completed the second plate after three long days. All that remains is a final torque of the bolts after the epoxy cures. The plates still need to be covered in foam and then a structural repair to the outside of the fuselage.

Date:  05-10-2019

Number of Hours:  8

Manual Reference:  no ref

Today did get one side completed. Here’s what happened.

I removed all the foam down to the glass underneath and this gives quite a level surface with little effort.

I’ve gone for 0.125″ (1/8″) 2024 T3 aluminium for my plate. I contacted one of our gurus asking about lightening holes. The answer was that maybe with 1/4″ plate but in this situation 1/8″ might buckle if highly stressed. The plates were too heavy for my 200gram limit scales. WE might be adding yet another pound or so with this beef up. So be it!

I champed the plate to the sides and used the existing holes as drill guides. I then added bolts as I went and removed the clamps. Most holes were accessible. The smaller bracket top ones I could just do with the right angle attachment above. I do have a 1/4″ chucking reamer so the holes were made good.

The lower two holes in the forward bracket are not accessible from the rear to drill through. Forget it.

I used an AN4 bolt and my large sanding disc and made a point by rotating it against the moving disk. Easy! Then I used the same technique to grind off the bolt head.

The idea is to put the ‘tool’ in the slot as you see above and then use the other holes to get the plate in position. Then I used a flat punch and a hammer from the inside and belted the tool so it made a mark in the center of our hole on the inside of the plate.

Here’s a look at the ‘tool’ and the indentation it made. I started with my smallest drill using the dent hole as a guide. Next was to drill it up progressively to .25″ constantly checking I was centered in the hole. It worked a treat. I did the same for the required second lower bolt hole.

With the final temporary bolts in place we are looking good.

I removed the temporary bolts and got my 8 x AN4-16A, metal lock nuts and washers ready. I then mixed some flox after priming the previously sanded plate and the fuselage cavity interior with pure epoxy. I then added lots of flox as a bed. The hardware went in, I torqued it all up to quite a low value and will get it to spec after the flox cures.

For an AN4 its 50-70 inch pound PLUS the resistance of the lock nut on a bolt. I’ll sort that after cure.

This side is done, there is a lot to do on the other side. The hardest part was getting the old bolts out. Somebody did an ace job making them permanent.

Date:  05-09-2019

Number of Hours:  8

Manual Reference:  no ref

This Long-EZ build will be operating up to 1800lbs at times. The original design was just 1325lbs. Over the years these planes have been built with many add-ons, like a starter motor, then bigger motors, heaters, electric nose lifts. People wanted more than just a basic fun airplane. My own build is for round the world missions and a LOT of extra fuel.

I have decided to mitigate against the main gear coming loose despite having already applied known fixes for this problem. Yes quite a few peoples main gear has gotten the wiggles, worsening over time. It only takes one heavy landing or an unseen pothole in a runway to cause main gear damage.

Using on line and then a private discussion, along with the input from a qualified structural engineer but mainly from one of the Canard ‘gurus’ I have begun the ‘FIX’.

The known fixes are to use a steel bushes for the large AN6-80A bolt, a flox donut to prevent the gear moving fore and aft on its large  5/8″ OD steel tube. I also changed the small AN960-4 washers for AN970-4’s some time ago. That was a lot of work I am about to undo.

All this is considered by some not enough. Perhaps another way to put this is to say there is a further measure. This is linking the 8 main gear bolts together on the outside of the fuselage with a plate of 1/8″ 2024-T3 aluminium. Feeewwwww. Its a big job, so lets go!

The first step was to get down to the bracket bolts on the outside of the fuselage. I needed to clean up the bolt edges enough to get a socket on to them.

As I had carefully epoxied these in all those years ago they were very hard to move. I used the known method of a soldering iron on the part that needs loosening up.

This is the area for the plate that has to go after I remove the bolts and big washers.

It was a long day when finally bolts and all the washers were out.

I’d also made a good start of getting the foam down to the level of the spruce longerons and reinforcement. From here it will be very careful sanding to get a level base for the large plate.