Firewall Stiffener Question

[David Paule]

For those of you using the firewall recess kit, how did you place your firewall stiffeners? These are shown on the top of drawing 19.

Thanks!
Dave

 

[Ironflight]

If we had to do it again, we'd wait on the stiffeners until after we installed the recess - and do the recess while we were building the firewall. We originally built the firewall to plans, with the stiffeners as shown on the drawings. Then a year later, when we added the recess, we had to cut the stiffeners in making the opening. I don't think the stiffener design is particularly critical (my opinion), and you could easily modify it to match the recess. I spent a lot of time staring at Randy's firewall pictures when I cut the hole for the recess!

Paul

 

[Bob'sRV6A]

Do I need a recess?

I have an O-360, with standard spin off oil filter and an SD-8 and Sensenich prop. The quick build fuselage has an opening in the middle of the firewall. Will the recess be needed, or can I cover the opening with a flat sheet of ss as sold by Van's?
As you can tell from the question, I am completely ignorant of anything from firewall forward.
Thanks

 

[Andy Hill]

David...

As with Paul, I'd hang fire. I've drilled the holes, would rather I haven't - but glad I've not rivetted the angles on.

 

[David Paule]

This looks like one of the things that ought to be done as a sub-assembly, before installing the bulkheads in the jig. And I didn't see any of these angles except for the perimeter ones - how did that work out? - which I'm not asking about.

So here's a follow-on question - is this the optimal position for the recess? This is one of Randy's photos, thanks Randy!

Thanks again,
Dave

 

[Andy Hill]

Hi David...

I would not go anywhere near the "cutout" until mounting your engine and accessories... Each will differ

A general tip for the RV-3 - various components interact with others, and do all you can to avoid finalising Component A until you have B as well... the RV-3 is not computer designed such that parts "match", and also the design has evolved a lot over the years, with altered dimensions - but not all the plans have caught up!

Another example is those "mounting pads" half way up the firewall - we have started those, such they fit the triangular webs, but will not finalise them until we have the mount. In fact, fuslelage is out of the jig, yet we have not fitted the rear spar carry through - again, that will await wing fitting and be fitted as part of the incidence / twist setting etc.

 

[David Paule]

Got it, thanks!

Dave