"Experimental 777SW" If they ask, what kind of experimental, then I reply "Romeo Victor -10"

Best,

Call sign
 

On initial call I use "Experimental RV 898 Delta Kilo." Using just Experimental and your tail number is okay but usually the next communication is "What type Experimental?" So I try to shorten the exchanges. After that first call it's up to the controller to designate what he wants to call you, e.g. Your full call sign or a shortened version.

For uncontrolled airports I use "Red RV 8 Delta Kilo". I don't see the point of using the full number as no one is there at an uncontrolled strip to see it or use it for clarity. I'd rather state my aircraft color so others in the pattern can differentiate a red airplane from a white one, etc. I figure it might make all the difference in preventing a mistaken identity someday.

Chris

Just the Facts!
 

Experimental one x-ray sierra. Occasionally asked for the entire call sign (November one x-ray Sierra).

Depends.
 

With a control tower the initial call is Experimental NXXXX, then followed by type.
With ATC I use RVXXXX.
When at uncontrolled fields I dispense with any numbers and just say red RV10 or such so everyone knows what to look for.

Vic

With a Tower I use: RV157GS Experimental.

With ATC I use: RV157GS.

Using Experimental 157GS is not clear as to what kind of Experimental the aircraft is. Experimental 12345 could be a Kitfox or a Glassair III. Both have different landing speeds and flight speeds near an airport. For a Controller to sequence the fight with others in a busy environment, they need to know more than Experimental with the least amount of radio chatter.

OpLims only require that I identify my self as Experimental to a tower and in the REMARKS section of an IFR flight plan.

For communications with any controller I use "Experimental White RV N509PE"

For uncontrolled airspace I use "Experimental White RV"

I use "Experimental N331JH". I found around here if I add "RV" it adds confusion and 80-90% of the time they hear "Army". Lots of Army traffic around here and near Fort Hood.

Here are the ICAO codes for the RVs along with the weight category. That's what the controllers see on a flight plan.

RV10 Vans RV-10 L
RV3 Vans RV-3 L
RV4 Vans RV-4 L
RV4T Vans RV-4T L
RV6 Vans RV-6 L
RV7 Vans RV-7 L
RV8 Vans RV-8 L
RV9 Vans RV-9 L

This begs the question, what is an RV-4T?

Isn't there an RV4 with a small turbine in it?

I was ferrying a AirForce B2 driver home one day and we started talking about this. One thing that stuck with me is he said he always takes the time to start every communication with a "good morning" or similar greeting, it makes it more personal and communications friendlier, nobody is too busy to be nice, I do the same now.