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  #1  
Old 07-11-2020, 09:59 PM
Peter Grylls Peter Grylls is offline
 
Join Date: Oct 2018
Location: Eaglehawk, Australia
Posts: 15
Default RV4 performance question.

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.
Thanks guys.
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  #2  
Old 07-11-2020, 11:34 PM
mattsrv7 mattsrv7 is offline
 
Join Date: Jul 2008
Location: Seattle, WA
Posts: 140
Default

I have a pretty stock 150 HP -4 with a wooden prop. Mine is a Props Inc. I'm maybe 40 lb lighter on the empty weight.

I generally get pretty close to the numbers Vans claims. Generally they are at a bit higher RPM though. Full power cruise at ~7500' yields around the 190 mph (165 knots) claimed, normally a few mph faster.

I think it is around 170 mph (148 knots) at 2500rpm but I haven't done enough performance testing for really good numbers at reduced power cruise.

Climb rate will vary greatly with the mission takeoff weight and density altitude. Solo with half gas, I generally see around the 1900 fpm claimed at sea level on a standard day. On a cold day the VSI will peg at 2000 fpm. Near gross weight 1500 fpm is about right.

Those are all standard day numbers.
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  #3  
Old 07-12-2020, 10:19 AM
Taltruda Taltruda is offline
 
Join Date: Oct 2017
Location: Las Vegas, NV
Posts: 323
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Quote:
Originally Posted by Peter Grylls View Post
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.
Thanks guys.

Is that 140 knots “indicated” or “true” airspeed? What altitude? Is it wide open at 140 and only 2500rpm? or are you throttled back?
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  #4  
Old 07-12-2020, 01:39 PM
CGVFR CGVFR is offline
 
Join Date: Sep 2011
Location: Radisson, quebec
Posts: 16
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mine is doing 145 kts @ 2000 ft , 2500 rpm without the Wheel pants.
prop pitch is 79 and engine is 160 hp. climb is 2000 ft/min solo and 1500 gross

cheers
Michel
CGVFR
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  #5  
Old 07-12-2020, 02:22 PM
Peter Grylls Peter Grylls is offline
 
Join Date: Oct 2018
Location: Eaglehawk, Australia
Posts: 15
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Quote:
Originally Posted by Taltruda View Post
Is that 140 knots “indicated” or “true” airspeed? What altitude? Is it wide open at 140 and only 2500rpm? or are you throttled back?
Speeds quoted are True.
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  #6  
Old 07-12-2020, 02:49 PM
Peter Grylls Peter Grylls is offline
 
Join Date: Oct 2018
Location: Eaglehawk, Australia
Posts: 15
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Thanks to everyone for the input. To clarify, all speed quote below are "true" air speeds at 10,000 ft.
2800rpm = 160 knots (184 mph)
2500 = 145 (167)
2450 = 136 (156)
2350 = 133 (153)
2250 = 131 (150)

I suspect it would go a bit faster than 160, but at the expense of an engine overspeed.
Prop is 68D x 72P.

I guess what I am asking is, do you think there is any appreciable performance to be gained by a prop change? Or do I save my money?

Sorry about the dumb questions, but I am pretty new to this RV game, & there are not a lot of 4's over here.
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  #7  
Old 07-16-2020, 06:08 PM
Rick RV-4 Rick RV-4 is offline
 
Join Date: Aug 2006
Posts: 255
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That does seem a little bit slow especially for those climb rates. If you were climbing at 2,000+ fpm you could maybe say you’re pitched for climb but not with the rates you said.

Have you verified the True air speeds with a four way ground speed check?

I’d try to borrow a prop from someone (if possible) to see what happens.
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  #8  
Old 07-17-2020, 02:48 PM
smokyray's Avatar
smokyray smokyray is offline
 
Join Date: Jan 2005
Location: TX32
Posts: 1,881
Default Ah Vee Fo...

Quote:
Originally Posted by Peter Grylls View Post
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.
Thanks guys.
G'Day Pete,
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...
V/R
Smokey
smokyray@rocketmail.com

Last edited by smokyray : 07-17-2020 at 02:57 PM.
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  #9  
Old 07-17-2020, 03:21 PM
Peter Grylls Peter Grylls is offline
 
Join Date: Oct 2018
Location: Eaglehawk, Australia
Posts: 15
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Quote:
Originally Posted by Rick RV-4 View Post
That does seem a little bit slow especially for those climb rates. If you were climbing at 2,000+ fpm you could maybe say you’re pitched for climb but not with the rates you said.

Have you verified the True air speeds with a four way ground speed check?

I’d try to borrow a prop from someone (if possible) to see what happens.
Quote:
Originally Posted by smokyray View Post
G'Day Pete,
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...
V/R
Smokey
smokyray@rocketmail.com
Thank you Rick & Smokey. It would seem that I am down quite a bit in performance, I will look into it further.
Smokey, that is the exact kind of data I was after. Thank you so much for your input, it is invaluable.
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  #10  
Old 07-23-2020, 04:10 PM
Peter Grylls Peter Grylls is offline
 
Join Date: Oct 2018
Location: Eaglehawk, Australia
Posts: 15
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Thanks again to everyone. For those that are interested, I went out yesterday & "fanged" around the sky for a few hours on a measured triangle. After doing all the appropriate calculations, it would appear my prop performs better than I thought. This is the data I recorded after two complete passes per test.

Average data at 8000 ft.
Speed at 2500 rpm = 145 KTAS or 167 mph
2700 rpm = 157 KTAS or 181 mph
W.O.T. 2850 rpm = 162 KTAS or 187 mph

It looks like my old Ian Henry hand carved propeller doesn't do a bad job after all.
Thanks guys, it has been an interesting experience for this newby.
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