Design Decisions
I put together the following laundry list of building decisions I made and the thinking behind them. I update it occasionally. It’s kind of interesting to see how my thoughts changed over the life of the project.
Taildragger or Nose-Wheel:
(2004) This wasn't a hard decision for me. Other than my Cessna 150 flight training, all of my flying has been in taildraggers. I just like them. Also, I think the RV's look better without the nosegear.
Seating: Side-by-side or Tandem:
(October 2009) With 84 hours on the RV and having given 15+ people rides, I'm very happy with the side by side decision. The passengers like it and I like having them next to me instead of behind. Performance-wise, hey, it's an RV.
(July 2008) As the plane nears completion, I'm still happy with the side by side decision. I'm looking forward to giving people rides and being able to look them in the eye.
(July 2006) I love flying the tandem Citabria, but I am looking forward to the side by side RV-7. The reason: passengers. I just don't think the passengers enjoy riding in back, unable to see the instruments or over the nose, and looking at the back of my head!
(June 2005) I still sometimes wonder that maybe I should have built the tandem RV-8 but mostly I think I’ll be happy with the wide body RV-7. One of my primary reasons for the RV is traveling, hopefully not alone, and passengers greatly prefer the side-by-side. Nothing against the 8, though; I'd love to have one.
(2004) This was a tougher call. The planes I currently fly, the Citabria and Ka-4 Rhonelerche, are tandem and I like them. The tandem RV-8 looks more like a fighter plane. That said, passengers simply like the side-by-side and for that reason, I went with the side-by-side RV-7.
PowerPlant:
October 2009 -- My Mattituck TMX-360 has been solid as a rock. Unless you're a gearhead and really know what you're doing -- and want to add hundreds of hours to the project, I can't imagine not going with a Lycoming or Lycoming-clone.
December 2007 -- The Mattituck TMX-360 is in the house, ready for mounting on the airframe. Carburated with one Slick Magneto and one Lightspeed Electronic Ignition.
January 2007 -- Still going with a Mattituck TMX-360, carbureted, with one magneto and one electronic lightspeed. The plan is to order the engine at Sun 'N Fun.
(July 2006) I've pretty much decided on the Mattituck TMX-360. Superior or SportAero finished out the short list. I like Mattituck because they are local -- relatively -- at Long Island, NY. Also I like buying American. I'll probably just go with a straight carb as opposed to fuel injection, primarily because it's the simplest to implement. I may swap one magneto out for an electronic lightspeed. I'll probably go with the standard, vertical sump, as opposed to the horizontal with increased horsepower, and cost.
(June 2005) I’ve come a long way on the engine decision. I gradually ruled out the alternative engines: Eggenfelder Subaru, & Deltahawk Diesel. They are just too leading edge with no major cost savings. I think the builder community has come to the same conclusion. Most everyone is going with the Lycomings or clones.
Gradually I firmed up on a new O-360. I wanted at least 180 HP for the RV, but don’t feel I need 200HP. I want a new 360 so I know the engine is good from the start and I don’t have to mess with it. Used 180s aren’t that easy to find; used 320s are common because people are moving up to the 360s.
I like the clones so that gave me a short list of Aerosport in Canada, Superior, Mattituck and Penn Yan. Aerosport has a great reputation in the RV community but I’d rather deal with someone in the U.S. I like Superior’s XP-360 and was leaning that way for a long time. But then I started learning more and more about Mattituck. One of their people is Mahlon who is the Lycoming authority on all the message boards. Then I went down to Sun ‘N Fun and went through Mattituck’s engine assemble/disassemble demo. They are real pros. I was impressed dealing with them when I bought magnetos for the Citabria. They are located in Long Island instead which is a lot closer than Texas. And finally, their engine runs on 91 Octane mogas just like Superiors.
So, I’ve pretty much decided on the Mattituck TMX 360 CS engine. The next question is carburator or fuel injection? As best as I can tell so far, fuel injection – provided you have a nice engine monitoring system – gets you fuel savings of about a gallon an hour. But it costs $2,000 more. It also means no carb heat, and no scoop on the cowl. Finally, you have to have it if you want the horizontal sump which increases horsepower by about 4% (7HP). However, I think the horizontal sump is an additional cost. I'll probably go with straight carburator. Compared to what I'm used to, a carb-360 RV-7 will fly like a nimble, hot-rod fighter plane..
(2004) To be determined. The major factor is cost. More horsepower costs more money. The minimum is 150 horsepower which is what a used Lycoming O-320 puts out. A newer O-320 puts out 160 HP. An O-360 puts out 180HP, and then an IO-360 delivers 200 HP. Along with the tried and true Lycomings, there are companies like Superior or SportAir that offer Lycoming-like engines with some attractive features. The Superior XP-360 can run on 91 octane mogas, which is an attractive feature given how expensive Avgas is these days. Honda is supposedly coming out with a new aircraft engine and so is Bombadier/Rotax. Then there are engines like the Eggenfelder Subaru and Deltahawk Diesel . There is a lot happening in General Aviation powerplant technology these days. The powerplant decision is one I don't have to make right now, but if I did, and I had the money, I'd get an O-360 (180 horsepower) with Hartzell constant speed prop. If money is tight, I'll get a used O-320 (160 horsepower) and wood prop.
Prop:
October 2009. The CS prop is great for slowing the speedy RV down in the pattern.
(July 2006) It's expensive but I'll probably go with the constant speed prop. I'll buy the Hartzell Blended CS prop through Vans.
(July 2005) The main options are: Constant speed, fixed pitch metal, and fixed pitch wood. I'd love to get a Hartzell Blended Constant Speed Prop but it's expensive. I may have to go with a Sterba wood prop in the interim.
Priming:
(July 2006) The airframe is pretty much built using the rattle-can on non-alcad parts the whole way.
(June 2005) I’m sticking with the rattle-can priming of non-alcad parts, although it scratches off more easily than I’d like. The rattle-can is quick and easy, and is about as much time as I want to spend on it. Now that I’ll have a hangar for the RV, priming is less of an issue.
(2004) Some design decisions are hotly-debated on the RV message boards and none more than priming. The two extreme's are no priming at all to priming everything with two-part epoxy. Van's says do what you want. After reading everybody's opinion, I decided to prime only the non-alcad components with Mar-Hyde, a self-etching primer that comes in a spray (rattle) can. Three reasons: 1) The Mar-Hyde is quick and easy and a lot less time-consuming than two-part epoxy, 2) to keep the aircraft weight low and 3) the protection afforded by the alcad-coated parts and Mar-Hyde is good enough in my humble opinion.
Canopy: Tip-up or Slider.
October 2009 Everyone loves the unobstructed, big bubble canopy. I can deal with a little greenhouse effect on the ground.
(July 2006) The Finish Kit is in the house so the die is cast. Tip-up. No regrets.
(June 2005) No change.
(2004) I decided to go with the tip-up canopy because of better visibility. The Slider, although cool on the ground, has a frame that looks to me like it would impair visibility.
Slowbuild Kit vs. Quickbuild Kit:
(July 2006) If I ever build another kitplane, I'll buy the quickbuild kit. Still, I have no regrets about going with the slowbuild kit the first time out.
(June 2005) I’ve enjoyed building the empennage, wings and now fuselage because of how much I’ve learned and how well I understand the plane. That said, if I was building a second one, I’d get a quickbuild kit. There are a lot of tedious hours required. I did buy pre-built fuel tanks and am incredibly happy I did. The wings took long enough as it was.
(2004) You can buy the quickbuild kits for the Wing and/or Fuselage from Van's. The workmanship is outstanding, and the timesavings are great. That said, the quickbuild kits add about $8,000 to the airframe cost. I'm building my RV-7 for the building experience as much as anything else, and I'll need the money for the engine, so I'm going with the slowbuild kit.
Avionics:
October 2009 -- Well, if money was no object, I'd rather have an SL-30 and a two-axis autopilot, but they certainly aren't essential and I didn't feel like coughing up another $4,000. That buys a lot of AvGas.
December 2007 - The Panel is pretty much done and powered-up. I havn't got the 486 yet -- waiting until the last possible moment in hopes the price falls -- but everything else is in place: the Dynon D180, SL-60, GTX-327, Pictorial Pilot, Airspeed indicator, PS Engineering PM-3000 intercom and Hobbs meter.
January 2007 - The die is cast. I've either ordered or already received all of my avionics. I have a Dynon FlightDEK D180 on order. It is a combination flight and engine instrument display system. I havn't ordered a 496 yet but I did order the AirGizmo panel mounting device for the Garmin. I ended up buying a used SL-60 GPS/Comm which has the same comm functionality as the SL-30 only a digital readout GPS instead of the VOR. I figured I'd rather have a second GPS for backup rather than a VOR. Now I don't need a wingtip antenna or the coax cable running out there. I ordered a Garmin GTX-327 transponder and I already have the TruTrak Pictorial Pilot.
(July 2006) Wow, what a difference a year makes. Oshkosh is in progress as I write this, so a bunch of new products and upgrades have been announced. Here is what I would go with if buying tomorrow:
EFIS/EIS: Dynon now offers a combined EFIS/EIS unit with 7" screen -- the FlightDEK D180. In September the screen will be twice as bright. I'll have an airspeed indicator and altimeter steam gauges for backup but that's about it. I figure the GPS and Autopilot provide good backups for the other things like attitude, VSI and turn & back.
GPS: Garmin 496. This just announced unit has terrain, weather overlay via XM satellite, AOPA directory in the database and a must faster screen refresh. The weather capability is expensive at $50/month but would be invaluable on cross-countries. I've heard nothing but great things about it. The RV is such a marvelous cross-country machine, that I'm just going to have to suck it up and get the weather. I'll mount the unit right underneath the Dynon using an AirGizmos panelmount.
Nav/Comm: I'm still planning on the Garmin SL-30.
Transponder: One of the Garmin units that looks good with the SL-30.
Autopilot: The TruTrak Pictorial Pilot.
CDI: I'd like to have one of these in my panel so I could fly IFR someday. Maybe I'll just leave a space in the panel for it, or I may try to buy a used one.
(June 2005) Lots of changes here as new technology has come onto the market and as I have learned new things. I’m going to divide this section up.
Electronic Flight Information Systems (EFIS) – There are lots of them on the market but the Dynon seems the best for my purposes. It is popular and has a reasonable price.
Engine Monitoring Systems – I really want one of these. The graphic display for each cylinder is most appealing. What we currently have in the Citabria – a single cylinder head temperature gauge and a single EGT gauge is practically useless. For a while, I wanted the ACS 2000 but it was expensive, more than $4,000. Recently Dynon came out with one that has the same functionality as the ACS2000 for almost half the price. Unless something changes, I’ll probably get the Dynon.
Nav/Comm – The Garmin SL-30 seems to be the Nav/Comm of choice in the RV world. It’s state-of-the-art, and is small, and modern looking. It allows monitoring a second frequency while using the primary. It has a glide slope receiver. It’s not cheap, but it’s a great Nav/Comm. The alternative would be a used Bendix/KingKX-125, the same Nav/Comm we have in the Citabria. It’s a good, solid Nav/Comm. It all depends on the financial picture.
Transponder – I fly in the Washington D.C. ADIZ so a good, reliable transponder is a necessity. I’d like to buy a new one from Garmin that will match the look of the SL-30 Nav/Comm. The alternative is a used Bendix/King KX-76A, which has worked well for us in the Citabria. Again, money is the driving factor.
GPS – I considered a panel-mount GPS/Comm because they are IFR-certified. But the handhelds have so much better functionality! I used a Garmin 295 in the Citabria and absolutely love it. But for the RV, I’ll probably go with the Garmin 296 with it’s terrain display and faster screen refresh rate. But things change quickly in the GPS world. Garmin just annouced the 386, featuring XM weather and audio. It also provides capability to display TIS traffic via the GTX 330 interface. The AvMap EKP-IV, with its large 7” diagonal screen – the 296 is 3.8” diagonal and the 295 is 4” diagonal -- might be a possibility as well.
Autopilot – Like GPS, autopilots are another technology where amazing systems are available for a relatively low price. The TruTrak Pictorial Pilot is what I would like to buy right now. It’s a wing-leveler autopilot that also displays turn and bank information. I have heard Van himself say that an autopilot is practically a requirement for IFR in an RV.
(2004) I like the Dynon EFIS. It includes airspeed, altitude, attitude, magnetic heading, turn rate, slip (ball), angle of attack, and vertical speed indicator. If I got one, I'd probably get a backup airspeed indicator indicator. For Navigation, I'll put the new Garmin 296 in the panel. I'd love to get one of those cool engine EFIS but, alas, too expensive for me. For cost reasons I'll just go with the usual engine instruments.
VFR/IFR:
January 2007 -- Of all the design decisions, I agonized over this one the most. In the end, I decided to go VFR. I just didn't want to spend the money for IFR. It wasn't just the avionics, it was the annual costs for charts, approach plates and database updates, not to mention the $10,000 to get my IFR ticket. I looked at how much I might use the ticket and decided the cost was too high. Another reason was that putting all the IFR stuff in the plane would have taken more effort, and longer until I would fly. Finally, the IFR stuff is more weight, weight serving no purpose 90% of the flying time. I may regret my decision; we will see.
(July 2006) Someday I'd like to get an IFR rating, and be able to fly light IFR in the RV-7. All I need to do equipment-wise is to put a CDI in the panel.
(June 2005) I knew absolutely nothing about IFR when I started building. I decided to get smart about it without going through the expensive lesson process. I asked Santa Claus for an IFR book and Microsoft Fligth Simulator. After reading the book and simulating flying around in a C172, plus reading message boards, I have a basic understanding of IFR.
In a nutshell, I could make my RV-7 light IFR capable by adding the following equipment: an SL-30 Nav/Comm (includes localizer/glideslope functionality), a CDI, a transponder, a Dynon (artificial horizon) and a single-axis autopilot. I’m probably going with the Dynon, SL-30 and autopilot regardless, so I might as well spend a little more and make it light-IFR capable. Again, getting an IFR-rating is something I’d like to do eventually.
(2004) I'm not instrument rated. It's something I'd like to do eventually. But for now, I'm planning on making my RV a VFR bird, although with the lighting required for night flying.
Navigation/Strobe Lights.
(July 2006) No change.
(June 2005) The Whelon System 6 is sitting down in my basement, ready for installation.
(2004) I'm going with the Whelon System 6, which is a combo nav light and strobe in each wingtip and the rudder bottom. Man, nav and strobe lights are expensive though.
Landing Lights.
(July 2006) No change.
(June 2005) There is a Duckworth light mounted in the outboard leading edge of each wing. They look great, and didn’t cost much.
(2004) I'm going with Duckworth lights, one in each wing.
Antennas.
January 2007 - I won't need the wingtip antenna since I won't have VOR.
(July 2006) No change.
(June 2005) I decided to go with the Archer wingtip antenna for the VOR and a bent whip antenna on the fuselage bottom for the COM. The only undecided question is whether I should put a second wingtip antenna in for backup.
(2004) I'll probably put a bent whip antenna on the fuselage bottom. Part of me hates to put an external antenna on this sleek bird -- I could put an internal antenna in the wingtip -- but radio reception is important, especially where I fly, in the Washington ADIZ. I know the bent whip antenna works well.
Paint.
January 2007 - I really like this paint scheme -- polished aluminum with gloss black tips -- so my RV is going to look like this:
I bought the Nuvite polishing kit at Oshkosh. My nephew-in-law is going to help spray the gloss black on the tips and tailfeathers.
(July 2006) No change.
(June 2005) No change.
(2004) I am more fortunate than most in this regard in that my brother-in-law owns his own painting company, is an aviation enthusiast, and has painted many airplanes. So I'll be painting my RV myself, with his help. I'm planning on painting the the fuselage, wings and tailfeathers separately, before taking everything to the airport for final assembly. I want to minimize the work I have to do at the airport, since it's 40 minutes away. It's early yet, but I'm thinking about painting my RV like a Grumman F8F Bearcat. Gloss Navy Blue with white U.S. Navy markings, and maybe a color band around the fuselage.
Interior
January 2007 - The Vans Air Force forums had a group buy on Hooker Harnesses so I bought a pair of five-point harnesses. I also bought a crotch-strap bracket kit from Van's and installed it. I bought a pair of Oregon Aero seat cores and Abbey at Flightline Interiors is covering them for me. My interior will be painted light grey using Rustoleum Hammered Finish.
(July 2006) No change.
(July 2005) The choices here range from nothing other than seat cushions to buying a custom interior kit. I supposed you could build a Cadillac-like interior yourself but that is beyond me, even if I wanted to. It can be done, though. Just take a look at the new factory-built ships like the Cirrus. At this point, to save money, time and weight, I’m just going with the bare bones approach. I’ll get a good Lightspeed headset for noise-reduction purposes.