I am fairly new to being around RVs and I still have trouble sometimes in being able to tell them apart. So, here are some of the things that I have noticed that you can look for.
Lets start out with the easy one, RV-10:
It has Gull Wing doors, is MUCH larger than any of the other RVs, and it has a roof. It is the only 4 place RV.
The next easy one is the RV-3:
These are a smaller than the RV-4, RV-8, and are the only single seat RV. It has the big puffy "Cheeks" (on the cowl) like the RV-4s, but the canopy is much shorter, as is the rest of the fuselage.
Next are the RV-4 and RV-8, both are tandem two place airplanes. The easiest way to tell them apart is by the roll bar.
The RV-4 has a triangular roll bar in between the two passengers, the RV-8 has a round roll bar in front of the pilot.
Other differences include size, the RV-8 is larger, and the "cheeks", RV-4s have big puffy "cheeks" RV-8s do not.
Lets start out with the easy one, RV-10:
![n104me5pn.jpg](/community/proxy.php?image=http%3A%2F%2Fimg223.echo.cx%2Fimg223%2F2990%2Fn104me5pn.jpg&hash=ddac572ad074d40e990818c83fc7c686)
It has Gull Wing doors, is MUCH larger than any of the other RVs, and it has a roof. It is the only 4 place RV.
The next easy one is the RV-3:
![rv30922200541lu.jpg](/community/proxy.php?image=http%3A%2F%2Fimg309.imageshack.us%2Fimg309%2F8899%2Frv30922200541lu.jpg&hash=8af55c45c669510a49b85a6aab8de1d2)
These are a smaller than the RV-4, RV-8, and are the only single seat RV. It has the big puffy "Cheeks" (on the cowl) like the RV-4s, but the canopy is much shorter, as is the rest of the fuselage.
Next are the RV-4 and RV-8, both are tandem two place airplanes. The easiest way to tell them apart is by the roll bar.
![aarv40gl.jpg](/community/proxy.php?image=http%3A%2F%2Fimg380.imageshack.us%2Fimg380%2F624%2Faarv40gl.jpg&hash=90fc6935e4c393a837a16af6a7f0f477)
The RV-4 has a triangular roll bar in between the two passengers, the RV-8 has a round roll bar in front of the pilot.
![PaulS.jpg](/community/proxy.php?image=http%3A%2F%2Fwww.vansairforce.net%2Fphotography%2FAirToAirPortfolio%2FPaulS.jpg&hash=f52b57ee4446411ff225fce882d69fb4)
Other differences include size, the RV-8 is larger, and the "cheeks", RV-4s have big puffy "cheeks" RV-8s do not.