HS brackets distance

I just started building my new RV-4 and first issue arose.

I drilled one side of each HS bracket to the spar.
Now, manual says to mate the other half of the bracket installing the bearing with nut and bolt and a thin washer (AN96010L). In this way the proper distance between the two halves is achieved and the second half of the bracket may be drilled on the spar, too.

Problem is that the edge-to-edge distance of the bearing itself is 16/32'' (not including the washer thickness) but drawing number 3 and 5 call for 7/16 gap. Also the bearing table at the beginning of the manual says a 7/16 thickness for MD3614M bearing. I measured those bearings and their "body" is in fact 7/16, but the edge-to-edge is 8/16''.

Now, if the distance between brackets is set to 7/16'', provided that the bearing overall thickness is bigger, torquing the nut will produce an angle in the bracket side, since at the top of the bracket, where the bolt is located, distance is bigger than that at the bottom of the bracket, where bracket is riveted to the spar. I guess this is not good.

So, I am almost convinced to distance them of 8/16''.
Will this be OK?

Thanks.
Camillo

I just marked the called out distances for reference and then used the bearing bracket assembly clamped in place to mark the final holes and didn't worry what the final spacing was. that way the bracket fits the bearings that you have with no load or twist to the bracket.

as Van told me, "your not building a swiss watch".

bob burns

RV-4 N82RB

Spacing.

Hi,

Think about what you are trying to achieve. You want the brackets spaced so that the bearing will sit between the two brackets without stressing them. So, if you set up the bearings as described in your first paragraph you will achieve this.

Provided you have the correct bearing the fact that there is a 1/16th difference in the measurements given on the drawing is irrelevant. What is important is the correct spacing of the brackets for the bearing being used.

When you move onto the elevators you will use these brackets to position the bearings in the elevator spar after fitting the elevator horn. This will ensure that everything lines up correctly.

Thank to both very much.
I will proceed as suggested.
Camillo

Steve is correct regarding matching the elevators to the HS. I would suggest then when you get your HS rear spar done, complete with brackets and the main bearing, that you now make your main elevator spars. It is much easier to match the elevator spars to the HS spar before the HS is skinned. The beauty of using this method is that you are able to bolt the elevator horns to the center HS bracket and then work outwards, attaching the elevator spar to the horns, then the bearings to the spar etc.
This will save you a lot of time in the future when you have to mount and rig the elevator to the HS. At that time there will be no need for spacers, washers etc.
Now you can go ahead and build the rest of the HS and elevators, knowing that everything will line up later. The same technic can be used with the VS and rudder.

Thank-you Tom.
I will look at the manual to understand exctly what I have to do now on elevators to save time later.
Camillo

Tom Martin said:

Steve is correct regarding matching the elevators to the HS. I would suggest then when you get your HS rear spar done, complete with brackets and the main bearing, that you now make your main elevator spars. It is much easier to match the elevator spars to the HS spar before the HS is skinned. The beauty of using this method is that you are able to bolt the elevator horns to the center HS bracket and then work outwards, attaching the elevator spar to the horns, then the bearings to the spar etc.
This will save you a lot of time in the future when you have to mount and rig the elevator to the HS. At that time there will be no need for spacers, washers etc.
Now you can go ahead and build the rest of the HS and elevators, knowing that everything will line up later. The same technic can be used with the VS and rudder.

Click to expand...

Wish I would have thought of doing this. This should be sent out as a "hot points bulletin".

Fuselage Interferance

When I made my HS I found that the inboard edges interfered with the fuselage when it was bolted on. Had I allowed 1/4 inch extra they would have been fine. As it is I had to file out the flanges to prevent it chaffing on the fuse skin. I dont have a photo but can take one if it would help.

I have to modify my question. I mistook the bearing type and took the bigger one. I should have trusted in Van's drawing. Will take it as an experience for the future. A really beginner mistake...

Bearing

Hi

Thats why I included the sentence 'provided you have the right bearing" in what I said, I wanted to suggest you check this first!!

Remember, measure three times...... then check what you are doing against the plans, then measure again...... then cut... or drill.

Another point to remember is that the RV4 plans are not the best Vans have ever put out. You sometimes need to check two or three sheets to make sure that what the first sheet seems to say,will not cause problems in the next stage of the build. There are several potential traps in there.

If in doubt ask on here....... it could save you a small fortune.