Originally Posted by Peter Grylls
Hello everyone. I have owned an RV4 for the past 2 years & absolutely adore it. It was built in 1990 by another owner & I have a performance question to ask.
It is a fairly "vanilla flavour" basic aircraft with an O-320-E2A 150Hp engine. Propeller is an "Ian Henry" 2 blade wooden prop. It climbs at 1500 to 1600fpm & cruises at 140 knots/ 2500rpm. Does that sound about right?
According to the Vans website, I should be closer to 165 Knots. I seem to be down quite a bit in speed which I assume would be attributable to the propeller.
I was hoping to contact someone with a similarly equipped 4 that I could compare with. My aircraft is a little porky at about 1015 lbs empty but the figures seem quite a bit out.
Great inputs from those above. I too built and owned a 150HP wood propped light, (925lb) basic RV4 "day fighter".
Back in the day (Post 9/11) Eleven of my F-16 Squadron mates purchased RV4's after seeing and flying mine. I compared performance numbers with the Eleven "store bought" RV4's with my own which varied in HP and prop configurations. What I found was my 150HP RV4 (which was properly faired, rigged and trimmed) would consistently perform 155 KTAS at 8500' 2500RPM
all corrected with 3-way GPS runs and friends flying alongside with their own calibrated instrumentation. On hot days I would climb solo full fuel at 1500-1800fpm at a 1000MSL Aerodrome 90F OAT. Full Throttle at 10,500' would render 169 KTAS at 2750RPM 19"MP. Engine overspeed above 10K is no big deal as long as MP and RPM combined don't exceed 48. IE 2400RPM/24" MP=48. 2800 RPM/19"=47.
Your numbers do seem a bit low but could be easily checked as mentioned above with HP/Prop and fairing evaluations. You can also fly 3 way GPS timed legs and take an average GS with OAT and IAS you can calculate TAS easily.
To ballpark TAS, for every 1000ft increase CAS (or IAS) by 2%. When I ordered my props from Craig Catto I strove for 2100 Static, 2250 takeoff, 2450RPM at 5000'=24" MP/155KIAS.
On takeoff I normally Accelerate to 100 KIAS/2400 RPM in ground effect then climb at 2400 to 5000' then 125KIAS/2500RPM to 8500'. Normal cruise is 2550 RPM at 8500' 170KTAS with a Catto 69/69 prop.
Email me offline if you have any questions...