Avionics Before Engine or Vice-Versa?

jpurban · #1 12-05-2009, 02:39 PM

Hi,

Just wondering how many of you considered doing your avionics/panel work after the engine/firewall-forward work was complete. I haven't built an RV and I'm not completely familiar with the required order of operations, but I'm assuming there is some choice on the matter.

Here is the reason I ask... Avionics (glass panels) are currently changing very, very rapidly, but engine technology is moving at a slower pace. It seems to make sense to delay the avionics "decision" to the last possible moment to get the best economics and options - kind of like buying a new computer.

Of course, the alternative argument is the engine and FF stuff is probably half the cost of the entire project ($30k+ for new). So, you might want to delay that cost until the very end.

Thanks for your input.

John

hydroguy2 · #2 12-05-2009, 03:17 PM

I chose both at the same time. Finances dictated waiting on the engine, but finally I couldn't stand it and started ordering everything.

Lately I get deliveries every few days.

Paul Thomas · #3 12-05-2009, 03:24 PM

I think you can do a lot of the panel work without having the gadgets; all that wiring takes a lot of time. I'd do that first. I'd then complete the FF stuff and then finish the panel.

I'm a long way from having to worry about it.

Bob Axsom · #4 12-05-2009, 03:41 PM

The engine will be the same five or ten years from now but the avionics will be obsolete by the time you receive them and going down hill from there.

Bob Axsom

rzbill · #5 12-06-2009, 05:22 AM

Might depend on whether you are wiring the avionics yourself or buying it complete. If doing it yourself:

While obsolecense is true, with EXP avionics, even the obsolete stuff is better than spam can equipment. Avionics don't have to be pickled for storage like an engine. They can be sold easily (except for items from defunct companies) if you change your mind.
Also, avionics cost can be spread out if cash flow is an issue. Avionics are not the only electrical system. There is a lot of wiring to do on other systems.

boom3 · #6 12-06-2009, 06:59 AM

As far as keeping busy on the project, I'd vote for panel / wiring before the engine. There is a ton of work here.

Chances are if you buy an engine now, it'll just hang there for 2 years while your trying to finish all the stuff you could have already done.

As for avionics, you'll never win the upgrade war. Skyview seems like a good choice now because its brand new. Chances are in a couple years it'll still be the same boxes with just better firmware.

Good luck!

mark schoening · #7 12-06-2009, 08:11 AM

I did avionics and fuse wiring first. Lots of tedious work behind panel made easier being able to rotate fuselage. Took me 3 months of winter work to wire panel, glass panel not obsolete a yr later. 'member , even if you wait, and you do panel last, shortly after new stuff will come out.

129TG · #8 12-06-2009, 08:38 AM

But a deal on the motor came by me that I just couldn't refuse. So, a little over a year ago I bought my engine. It came off a flying RV8 and included everything FF. I installed all the pieces-parts I could at the firewall (contactors, battery trays, holes, grounds, et. al.) and then mounted the motor. While doing engine related mini-projects, I designed the electrical systems. (This took me twice as long as I had expected) Then while installing the busses, strobes, trim servos, AP servos, engine related probes, I designed the panel. It took me forever to get to a point of satisfaction with the panel, but I did. I had made up my mind long ago that I wanted GRT glass but waited until this point to order. Now, I have all my avionics and my panel is due to be delivered Tuesday of next week. Right or wrong, this worked for me. I can't think of a thing that has caused me any additional grief had I waited or sequentially changed my processes. One other point I'd like to make is a friend of mine talked me into keeping my project setting on a roll-around dolly that was about 8" off the deck. This put the fuse at about waist level. I wanted so badly to put the fuse on its' gear but resisted. I highly suggest you keep it low so that you have workable access to everything including wiring. That's my 2 cents...

RV7Guy · #9 12-06-2009, 08:49 AM

Money is always a consideration however, the logistics of installation for me was a huge consideration. When the engine is on, the plane is on the gear and sits very high. Way to high for me to work on the panel and wiring. Without the engine I can use various sized saw horses to get a comfortable working height.

The only real consideration is EFIS systems. Radio stacks won't see any changes. Regarding EFIS systems, I think they are reaching a level where the screens and boxes won't change much and the changes will come in software.

What I do recommend is not buying any of your radio gear/EFIS systems until you are only a few months out from flying. You can accomplish virtually all of your install by purchasing the mounting trays for the radios and EFIS and mounting them. Once this is done then you can do the engine work. Before you are ready to nail down that front skin, order the gear for trouble shooting and finish up. This reduces the amount of warranty that is getting burned up not flying.

Bavafa · #10 12-06-2009, 11:56 AM

I was planning on delaying my engine purchase till I was ready to hang it up, but a great deal came about from Lycoming that I couldn't pass it up but I got them to agree not to build the engine till I was ready for delivery. As for avionics, once I had decided which system (went with GRT) they sent me empty cases of AHAR/Mag and other parts to build tray and do the wiring and I received the actual parts once I was ready to mount them. My goal was not to have parts till I was ready to use them. But I hung the engine first before the major part of wiring was done.

Mehrdad
RV7A - IO360M1B