canopy too short

Hi folks,

I've trial fit my canopy and run into a problem: the canopy appears to be too 'short' with respect to the front bow.

Holding both sides firmly against the canopy frame, and with the latch hole as far forward as possible against the tube in the frame, I can't get the front edge of the canopy to be any closer than 1/2" to the aft edge of instrument panel cover. In other words, the front edge of the canopy lies nearly directly over the front bow. The Book states that I can shave the latch hole by 1/8", but that will still leave me 3/8" shy.

I haven't cut or trimmed anything at this point.

Comments or advice?

Thanks in advance,
-dbh

? is the canopy to short.

Is the roll bar in the right place, is the space between the roll bar and the canopy frame right.
post photo if possible
Joe

dbhill916 said:

Hi folks,

I've trial fit my canopy and run into a problem: the canopy appears to be too 'short' with respect to the front bow.

Holding both sides firmly against the canopy frame, and with the latch hole as far forward as possible against the tube in the frame, I can't get the front edge of the canopy to be any closer than 1/2" to the aft edge of instrument panel cover. In other words, the front edge of the canopy lies nearly directly over the front bow. The Book states that I can shave the latch hole by 1/8", but that will still leave me 3/8" shy.

I haven't cut or trimmed anything at this point.

Comments or advice?

Thanks in advance,
-dbh

Click to expand...

When you test open/close the installed canopy frame does the forward canopy bow barely clear the top of the instrument panel (with the avionics top cover in place to ensure proper panel positioning)? As I recall, I had to tweak the forward canopy bow a bit aft to fit per the plans. Again, as I recall, the front edge of the plexiglass is not supposed to meet the aft edge of the top avionics cover, the plexiglass merely needs to set on top of the canopy forward bow so you can set the rivets. The fiberglass canopy skirt eventually fills the gap. Pictures would help.

some pics

Joe, David, others

Here are some pics for you. To answer the questions: the front bow clears the instrument panel comfortably and did not require any tweaking. It measures to spec 7/16" and didn't require any manipulation. The Roll Bar assembled without any complications. The Canopy frame (inside face) is being held 1 7/32" by the 4 wooden blocks in the kit (I didn't use the correct dimension the first time:roll eyes:.)

As you can see, the canopy does extend over the roll bar, but only about 1/4". I'm worried that I'm too close to the edge to place rivets without cracking or having a wedge break (two cracks in a "V" that allow a portion of the plexiglass to just break off.)

Thanks again for you input.
-dbh




Lateral View of Front Bow and Instrument Panel


Lateral View of Front Bow, front of Canopy and Instrument Panel

In this particular shot, the Canopy is not exactly square. When squared off, it measures 5/8" from the edge of the top cover in 3 places.

The front edge of the canopy doesn't extend right to the edge of the panel and from memory 1/2" short sounds about right. Otherwise the canopy edge will catch on the panel as you open the canopy. I'm not sure where you're measuring the 1/4" from. Is it from the contact point of the canopy on the front bow or from the front `edge' of the canopy bow?

After flying today in my RV-12, I measured the distance of my forward canopy edge to the centerline of the rivets that secure the canopy to the forward bow. On my canopy, the dims are: @ 5/8" at the left and right ends and @ 3/4" at the center of the bow. I did not have to adjust the canopy latch hole when originally fitting the canopy.

Your web site pictures are very good!

Is the roll bar in the right place

Without the tail cone the Roll Bar may not be in the right Place

The rivets should be about 9/16 to 5/8 from the bottom edge of the window

No less then 1/2 inch

joedallas said:

Is the roll bar in the right place, is the space between the roll bar and the canopy frame right.
post photo if possible
Joe

Click to expand...

problem might be solved

I might have figured out part of the issue. I went out to measure my plane to see how far away I am from DHeal's numbers. With the canopy firmly clamped at the spec'ed 1 7/32", my front edge of the canopy is only 1/4" away from the contact line visible on the masking tape, which is pretty far away from DHeal's ~3/4".

To answer rgmwa's question, the 1/4" that I'm looking for is called out in Fig 2 p 34-03 rev 2.

With my son helping hold the canopy from falling off, we unclamped the roll bar and did some pivot testing. My canopy just barely clears the front edge of the instrument panel. When we put everything back down, viola! the front edge is now at the specified 1/4" and there's about 3/4" of overhang in front of the bow. In short, it looks perfect.


Apparently perfect fit! Or is it ...

Now, my only question is whether the frame has to be clamped at 1 7/32 at this stage or not. The Book says that the clamps may be loosened on p 34-06 step 3. One interpretation is that the blocks are needed only when verifying that the front bow is 7/16" from the panel, but are not needed after that.

What I'd like to do is leave the clamps off, trim the edges, leave the front and back alone, and proceed with drilling.

-dbh

I don't recall my exact sequence of assembly, but I'm pretty sure I followed the plans. Be careful that you don't make that forward gap between the canopy forward edge / forward bow / avionics cover too tight -- the finished canopy tends to twist / distort a bit when you open it from either side handle and a bit more of a gap is desirable.