Originally Posted by KHeidorn
I have experience with auto body repair. so, adjusting and aligning up gaps on adjacent panels is not new to me. Even without the experience I think the instructions cover it well. The scribe lines are very close and the cowl halves seem to be of very nice quality.
I did have to reshape the front left corner to fix some alignment issues. I don't know if that was my fault or the cowl design. I ended up having to lay some fiberglass on the inside to build up the reshaped area.
I will be interested to see the flap position sensor kit from Vans. I didn't mind fabricating my own. Since I was waiting for the finish kit it gave me something to do.
Glad to hear good experiences with the cowl from a couple of builders.
The cowl halves as molded will match up very well if positioned properly, but it is easy to get a slight mismatch at the very front, because just the slightest distortion in shape (from pulling at one point or another) will tend to move these points out of alignment (that is true for all of the RV models).
The most important detail when installing an RV cowl is to resist pulling it to a position you want, that it doesn't desire to be in when not being forced. This will have a huge influence on how hard it is to get pins in and out, and how well the cowl holds up to vibration over time (broken hinge loops and rivets, etc.).
The evidence of a well installed cowl is that with the top cowl sitting in place with no pins installed, you can't tell. The top cowl will lay in place fully aligned with all of the gaps looking the same as they are when the pins are in place (with the exception of the top rear.... it will tend to slide fwd very slight and make that gap slightly bigger.
y point in this is to say it is much better to fix mis-alignment issues by adding a little bit of Fglass and some sanding, than it is to force the cowl into the position you want while drilling the attach holes.
The process detailed in the plans is designed in such a way to try and help with this, and to prevent people from over trimming which will temp them to pull the cowl to a position that will fix their excessive gap.
Tension within the cowl will make pins harder to insert or remove.
.125 pins (just like on the RV-10) are being used around the back because it maintains a much better fit and prevents the poofing out that that can happen if the .090 pins are substituted (like is used on the other models).
If all of the install details are followed (shape adjustments done to the top aft hinges, pins pre-shaped to match the curve of the firewall, proper end treatment done on the pin, etc.), the .125 pins go in and out nicely. It is a bit more of a challenge with the tail dragger because the nose sits so high... I have to use a small step stool to reach inside to remove or install the pins (I am about 5' 9".
As a standard maint item, I lightly polish cowl pins on all our airplanes every time I remove them for an oil change. Then I rub them with Boelube. They always go in and out nicely.
If an RV-14 builder ends up with pins that after flying for a few hours are just too tight, they can substitute .090 pins (which is probably a good plan, so as to relieve some of the stress that is likely built into the cowl).
The Van's designed sensor installation is not much different from yours.
The sensor mounts on the upright channel at the back of the flap motor enclosure, with a wire connecting to a flap torque tube arm. The main diff is that the wire is isolated from contact with the steel arm so that it wont wear over time from vibration, etc.