Someone asked this in the SR22 thread.
I think the reasons will include
Anything else?
I have just done a google for images of a crankcase breather pipe (because I need to buy a piece of it) and found some photos of the RV setup
That uses really good quality parts – quite unlike some stuff I have seen on another brand of homebuilts. Except for the EGT/CHT probe wires which are not secured properly… but that is a builder issue, not an RV issue.
The one you missed (other than it being part of ‘flying well’) is that the numerical performance is extraordinarily good for an aircraft as otherwise simple and practical as an RV. Van is an excellent designer in that he knows how to make simple designs perform better than many complex designs. It seems to derive from keeping the design light (weight most definitely does affect aircraft performance) and understanding what drives performance in terms of wing design and fairings etc.
Another is the cost being accessible to the average middle aged, middle class American, and others at similar economic level worldwide. A fraction of the cost of a comparable factory assembled aircraft.
Also, in relation to prior similar designs (e.g. Thorp T-18, Mustang II or Pazmany PL2) an RV takes substantially less skill to built, particularly with the amount of assistance and advice now available from large numbers of other builders.
They are straightforward, of conventional construction, and they go fast without having a high stall speed and even higher landing speed or needing retractable gear. Subsequent owners (in the US only the builder can sign off the annual, subsequent owners have to take it to an A&P) know that due to the conventional design, no A&P will have any problem working on it unlike some of the more exotic designs.
they go fast without having a high stall speed and even higher landing speed or needing retractable gear
But doesn’t that bring a heavy cost on the fuel burn side?
(to anyone outside the US, I mean)
they go fast without having a high stall speed and even higher landing speed or needing retractable gear
Jan_Olieslagers then wrote:
But doesn’t that bring a heavy cost on the fuel burn side?
(to anyone outside the US, I mean)
Jan, the comparative fuel economy depends on your objective. RVs get great economy in terms of fuel used per nautical mile, and not too bad in terms of fuel used per hour. A friend who likes to fiddle and try stuff often flies his RV 8 at 5.5 gph economy cruise (21 L/hr) while doing something like 145 kts TAS. Don’t hold me to that economy cruise number (I’ve forgotten the exact number he told me!) but its pretty high regardless. So you can get to far away places fast and cheap in comparison to most other aircraft, and also fly locally without a tremendous fuel burn per hour, although more per hour than an aircraft with 80 or 100 horsepower.
I think a Falco is probably a little better in economy than side-by-side RVs, but with less straightforward construction (primarily wood) and retractable gear. An RV 4 might match the Falco in economy but with tighter tandem seating.
I think what also contributes to the success of the RV-kits is, that riveting metal obviously attracts many homebuilders more than splashing about in sticky resins. Plus you can shoot in some rivits in an hour after work and go on the other day where you’ve just stopped and layed down the tools. Not so with composite materials and not to talk about endless sanding for perfect finish. That’s the reason why I bought my Europa second hand.
RV’s are also very economical, but can’t beat a Rotax-powered Europa in this regard, which can also use MOGAS (quite popular in Germany). The wings come off in 10 minutes, so trailerable etc. Relax, I won’t start a “Europa is better discussion”, just only talking about Economy, not performance 
No doubt, the RV’s are fantastic aircraft which sell by far better than any other kit (even beats the Europa in England by far in this regard – unfortunately).
The main disadvantage of resin/fibre construction is indeed that a lot of time goes into preparation and cleaning up – so you can’t do “just an hour after dinner”, or it is terribly inefficient. Working with resin isn’t exactly healthy either, the products themselves have their negative sides plus one is breathing acetone all the while – ask me how I know! And yet another disadvantage of resin/fibre is the climate limitations – you don’t want to do that job on a foggy winter day, you’d only produce rubbish (depending on the products used). BTW my own dream design would be alu mostly, with some fibreglass work at wingtips, wingroots, engine cowl, wheel pants and such.
Regarding economy of operation, and somewhat contradicting my earlier scepticism: couldn’t an RV be equipped with a Mogas-approved Lyco/Conti variant? Fuel burn per hour would still be higher, but the better speed could make up for that?
Sure enough, many RVs can (and do) operate on mogas. Why did you think they couldn’t?
@Peter, regarding the photograph: quality materials they may be, but were they part of the kit, or did the builder make good choices? Even then, the hose clamps on that blue elbow look like home market stuff. Actually I do not like that blue thing at all, it is too much bended. Why not create the 90 degrees in the metal tube, too? But perhaps the required coupling wasn’t available.
And indeed the bundle of wires screams for better fixation, and probably thermal protection, even if it is the correct white stuff.
boscomantico wrote:
many RVs can (and do) operate on mogas. Why did you think they couldn’t?
I did not think so. Where did I state that? I know next to nothing about those engines, so I am unsure for which models a MoGas conversion (or certification) is available.
