Fundamental Decisions About Cockpit Layout

This post starts with a recent attempt by me to search VAF for some info about Wing Stands and Jigs that may have been posted by Paul Dye (VAF user Ironflight). This is a gentleman whose wealth of knowledge I have come to greatly respect throughout my experiences thus far with building the RV8. He contributes articles frequently for Kit Plane Magazine and was a systems engineer for the Space Shuttle and Space Station programs at NASA. If anyone knows about all things "experimental" when it cmes to aviation - he is certainly one of those individuals.

Anyway I had heard that he had a simple wing jig solution and I was trying to find a post to that effect - that is until I stumbled on a couple of posts from him back in 2006 after his RV-8 Valkyrie was completed and flying. Doug Reeves, founder of VAF, had captured several pics of his panel layout, and as I started studying the photos there were some comments about the reasoning behind his panel layout that I did not want to lose reference to.

So this post is now dedicated to a small tidbit of information about some things that I must not forget when the time comes to figure where all the goodies will go in my instrument panel and various consoles on either side of the pilot seat. I like Paul's reasoning for why he put certain things in certain locations, and will plan on emulating those same considerations in my own plane when the time comes. Here is a list:

1. Overall he tried to group common items in the same locations to make it easier to locate systems with similar functions.

2. All primary electrical switches are located on the right console next to the pilot seat

3. All engine-related controls are placed on the left console, including the engine monitor.

4. He used a rail system on either side of any essential electrical switches to provide a bit of stability for manipulating the switches during turbulence - a technique used extensively at NASA. Gee, I wonder why?! The rails provide a platform to rest your fingers against to help actuate the switch, and it also prevents inadvertent activation of a switch by bumping into it with your hand or your knee, etc.

5. He placed his avionics that require the most interaction with the hand and fingers so that his dominant hand performs the actions such as turning small knobs or pushing small buttons, etc. He discussed this with some human factors engineers at NASA after initially planning to place the radios in the opposite location. His initial thinking was that his dominant hand should be focused on flying the plane so that it would be on the stick, and the weak hand would do all the radio switching and tuning work. He was advised to change his perspective, and allow his dominant hand to take care of the fine motor skill work, and the weak hand to focus on the joystick work. For me this means that the radios and GPS should be on the right side of the Primary flight displays if at all possible.

5. Then I encountered some interesting tidbits about nav/strobe combination lights. I noted that Paul seemed to have a 3-position switch for his strobes - top was ALL, middle is OFF, and bottom is TAIL ONLY. My current thinking was to put a combination red/white beacon on the bottom of the fuselage if that will satisfy the FAA requirements for visibilty to the rear. I also finally found post in the builders log from someone else that confirmed that the Wing tip Strobe location that Vans provides DOES NOT meet the requirements for rearward visibility of the anti-collision loght system, and therefore this discrepancy in their design needs to be addressed somehow. Putting the strobes in the wing tips, as most people do, only allow visiblity from the side and the front, and NOT from the rear. This is, in essence, a violation of the relevant FARS that I have reffered to in previous posts that is excrutiatingly specific about the distance, number of lumens, and angular visiblity requirements for the required exterior light systems.

6. One last thing that I noted about his overall panel layout, as well as those from several other builders, is that he retains the basic scan format with his backup airspeed indicator positioned on the left side of the EFIS display (which provides attitude display in addition to the other information when everything is working), and the altimeter on the other side. The backup attitude indicator is located elsewhere on the panel. I have seen several builders emulate this configuration, and then I have seen others that tend to try to keep all 3 backup instruments in one line across. The problem is that the EFIS is always in the way in the small panel space provided by the RV-8. This makes positioning all 3 backup instruments together in a location that will be readily viewable by a pilot that needs to use them in an emergency a bit of a challenge.

There are numerous schools of thought out there on the positioning of the backup instruments. One interesting insight is that if the backup instruments are located in a position that is readily viewable by the pilot most of the time, then the they tend to focus on the back up instruments instead of the EFIS for primary flying tasks, even when the EFIS is working perfectly. I am almost of the opinion on this that I would rather have a backup EFIS on a secondary power system so that not matter if the primary EFIS fails, I am still maintaining reference to flight instruments from a similar display. Works pretty well if you have the extra cash and the extra panel space to go with it such as in a side by side RV like the RV-7, etc. This does not work as well in the RV-8, where panel space is at a premium. Anyway, when the time comes, I may keep the backup round dials in a single line or I may break up the attitude indicator - just not quite sure how I will decide to do that yet.

There was also a comment about putting a combo nav light/strobe in the tail. Somebody mentioned that this is a major distraction for a low wing airplane at night, with the light reflecting off the wings from the rear, possible entering your peripheral vision. So he recommended not putting a strobe in the rear. I am hoping my decision to place this system on the bottom of the fuselage eliminates this problem, but I am worried about electrical noise affecting the ADAHRS unit for the EFIS, which will also be mounted in the rear of the airplane.

So much for checking out wing jigs! Here is the link to the post that contains Ironflight's panel photos.

IF I can just shed some of the cold weather that finally appeared in Colorado I am just about ready to re-engage in the wing work. Personally I will be glad when the holidays are done and over with - I need to get back to building an airplane.