One of the reasons certain amateur-built aircraft models have been so popular is because there is a whole cottage industry of aftermarket items available for them. Initially this effort was focused on tools to facilitate the build process. We saw improvements in dimple dies, fiberglass cloth cutters and complete “starter” tool kits being marketed to first-time builders.
Soon after that it seemed that there were people offering their services to help build aircraft and even making “improvements” in the original designs. In some cases, it spawned new models, such as the Rocket series of aircraft originally based upon the Van’s RV designs, both of which have been successful.
I believe the explosion of 3D printing is probably going to make an even greater difference in both the building process, through the use of jigs and templates, and in the aftermarket product availability. I think it will allow products to come to market faster and cheaper, breaking down some barriers to creativity.
I remember showing up with my RV-4 to Oshkosh in 1983. It was completely different from the other RV-4s in that it had an interior. There were some “persona-non-grata” vibes from the RV crowd as it was kind of unspoken that the RV was supposed to be spartan and light. Hmmm. I knew it needed to be comfortable. Carol was going to fly in it, so who was I to complain, especially since I benefited?
Fast-forward a few years and there were multiple companies making interiors for the RVs, some of which are still going strong today. I think they did a wonderful job of fulfilling a need. Today, I think only about 5% of the RVs I perform a prebuy inspection on do not have an interior. A quick look at most sales ads for RVs will definitely show the interior as a highlight.
Today you can find anything from upgraded door handles, Teflon hoses, retractable gear and turbine power mods. It’s almost impossible to discern which ones are really “needed” for your aircraft from those that are just nice to have or may just be a marketing ploy. I would recommend that for some of the aftermarket accessories, the old caveat emptor (buyer beware) should certainly apply. How do you know when to apply it? Look for established companies with enough installations that you can form an opinion of builder happiness. The more successful installations and customers willing to go that route again are strong signs. If you’re the first customer, you’re really still a beta tester. It’s OK if you’re prepared to be, but know ahead of time.
Looking at Aircraft Modifications
I’ve seen a lot of mods over the years. Here’s my take on a few.
Let’s start with speed mods. It seems every pilot is always wanting to go faster. One of the most prominent speed mods I see on the Van’s aircraft has to do with both speed and cooling in the form of a cooling plenum on the engine and different inlets on the front of the cowling. To be candid, the cowling looks nice with the rounded inlets, but I find the plenums to be a pain.
First, most of them are not built correctly in a couple of ways. They are usually too close to the top of the engine to prevent the plenum from rubbing the cowling and therein lies one problem. For the air to cool the engine properly, it needs to have room to slow down and change direction by about 90°. My experience with our customer base is that the plenums cause higher temps.
Second, the cylinders do move around quite a bit when the engine is running, so the baffling and plenum should not be hard connected between the cylinders. The plenum needs to flex. I have yet to see one that accommodates this need and consequently it causes cracking in the plenum, which I’ve seen in the field. The plenum is usually more efficient at capturing all of the intake air and moving it past the cylinders, so usually there is a need to increase the outlet area of the lower cowling or the increase in back pressure will contribute to the higher cylinder temps. Lastly, the plenum can be a real pain to remove for maintenance as the top is usually held on with a large number of screws. This is, in my view, a case where the improvements aren’t worth the compromises.
Another speed mod not as prevalent is retractable landing gear. I’ve heard from one vendor that he only needs a couple of more orders and he will be able to make a production run for the RV-10. I wonder about the practicality of that mod. The complexity of a retractable landing gear modification is not to be taken lightly. There will certainly be structural concerns that will need to be addressed and the extra weight of the retractable gear, hydraulic pump and hoses will certainly detract from the useful load. It would also seem that a well-engineered solution would need structural data that I’m sure Van’s isn’t willing to share to the world.
I would also bet that the insurance will be more costly. Let’s just say you could improve cruise speed by 15–20 knots—it will only make about a 15- to 20-minute difference on a 3-hour flight. To me, that’s hardly worth it and I don’t think we will be seeing any RV-10s on the racing circuit. Personally, I think taking the time to build a nice, clean, well-rigged airplane, along with the right propeller and perhaps some porting and balancing of the engine, will do more for the longevity and value of the aircraft. But that’s just me. Experimental aviation is just that and to each their own.
Another mod I am seeing more often now has to do with having oxygen available for the entire cockpit. I think it’s an expenditure that won’t get used very often and it also makes getting oxygen refills a little more difficult, as usually the bottle is hard mounted behind the baggage bulkhead. It has been my experience that just about all our flights requiring oxygen are usually solo or only with one other occupant. Rarely have I seen the need to take three or four people on high-altitude flights. So that means the oxygen bottle would always be carried in the airplane, whether it’s used or not. Why accept the weight penalty? I’ve always used a portable bottle, which we can fill at home, and it is equipped with a four-person regulator so if it’s ever needed, it’s there. After 3600 hours in the RV-10, it’s never been needed.
Now That’s Practical!
There is a practical mod for some of the two-seat RVs that I really like and it has to do with easing the loading of the baggage for aircraft with a slider canopy. There are a couple of companies that make the modification, but basically it allows the canopy to either tip up or slide farther back, enabling you to load the baggage from outside the aircraft rather than struggling with it over the top of the seatbacks. I think it is a very practical modification and we have been asked to do several of them.
For those of you who plan to do any night flying, I would recommend that you take the time to put the brightest lights possible in your aircraft. It seems to me that as you get older you just can’t get enough light. At least that is my experience. The advancement of LED lights has made night landings so simple. With the right amount of light, properly aligned, it’s almost hard to justify logging a night landing!
Coming up in this space: I will continue to discuss some modifications I think can be of value and even some that are safety enhancements. In the meantime, I’m working hard on the RV-10 and making good progress. It’s my first “slow-build” RV-10. With approximately 700 hours into it, I am still not at the quickbuild stage. Aargh! But I am keeping my fun factor alive thinking about some of the modifications I am planning for it.
