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RV-4 Performance: O-320, Sensenich Metal Prop

Jumbo

Well Known Member
Hi,

I recently did a performance flight with the RV-4. As it is a RV-4 which can be considered somehow a ´standard RV-4´ with an O-320 and Sensenich Metal Prop this might be of interest to others (however I have seen people asking for or discussing such data):

2cz6lq0.jpg


So - with full fuel and a 215 lbs guy on bord it is a real 165kts / 190 mph plane indeed even at temps just above standard ...

Best, Heinz
 
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Performance numbers

Just out of curiousity, was it 165 knots or 180 MPH? Only asking because 165 knots equals 190 MPH. Also, was this Indicated, True, Calibrated or Groundspeed? Not splitting hairs, but that could be a pretty big difference.

Just curious so I can make the best comparison. Either way, those are good numbers!

Thanks!

Rick
RV-4 N999XS
 
the table has 2 speeds

Rick,

the table I have posted has 2 speeds: IAS and TAS (all in knots).

The IAS I read from the Dynon D-6 and the TAS comes from putting IAS and OAT into the GPS (it uses with GSP ALT and it calculates Density ALT and TAS than) - I use the same system in other planes and it matches up within 1-2 kts of the TAS I get ie. from a Blue Mountain EFIS so it is pretty accurate.

And indeed 165 kts are ca. 190 mph (189,87 mph to be precise - :confused:) - I posted ´180´ which was a typo so thanks for pointing this out.

I am very impressed by the performance of this plane actually and it meets the Vans numbers for the O-320 (160HP) wood prop combo:
Vans mumber for Cruise [75% @ 8000 ft] is 193 mph at Solo Weight of 1160 lbs - PH-EIL at 71% => 194 mph TAS at 1360 lbs
Vans mumber for Cruise [55% @ 8000 ft] is 174 mph at Solo Weight of 1160 lbs - PH-EIL at 55% => 174 mph TAS at 1360 lbs

Heinz
 
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I'll buy that for a dollar...

Heinz,
Your numbers are right in line for the 0-320 powered Four. 0-320 powered RV4's fly the best in my humble opinion, this coming from alot of personal sample data :)
One thing to add to your excellent table is Mr. Mooney's claim way back in the 60's on the Mooney 201 design, "1MPH per HP." A properly faired 0-320 RV4 easily delivers and exceeds this with well beyond 1 KNOT per HP TAS at 8500', quite impressive for a thirty-year old design. The 180HP RV4 can't quite match this HP vs Speed equation as Van so well points out in an RV8R article back in 89'. Back then we all tried to get the "most bang for the buck" coming in as light and simple as possible. Part of every builders claim in the completions column of the original RV8R was how much it cost to finish and how efficient it flew. The new generation of builders seems to like the claim of how much "buck for the bang?" Most with dueling EFIS's, Autopilots and lots of bells and whistles. But I digress.


I think an 0-320 powered four would be in the top three of any competitor future or past for pure efficiency in a 2 place sport-plane.

Quite impressive I must (still) say...

Happy Vets Day!
Smokey

PS:Even more interesting numbers most RVer's don't explore is the lower speed range. How fast do you go at 5GPH? How slow can you fly final or what is the shortest strip you've landed at? How slow can you go over the top in a loop (or gun someone in a dogfight:)? My four would cruise easily at 125 Knots at 5 GPH. Even with 32 gallons that is impressive (bladder challenging) range. My home strip at 900' long wasn't difficult, and flying final at 60 Knots is very easily attained with practice. Sport aerobatics included! So, what other airplane delivers these amazing capabilities?
 
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If I will get even more in to hairsplitting all will become academic ...

I was thinking about what is the best power setting for my typical leg which is ie. from Muenster (EDLT) in Germany to London Denham (EGLD) in the United Kingdom (327 NM one way).

My normal power setting is 65% (ie. 21" MAP and 2400 RPM at say 5000 FT - there is an airpace limitation and I am not allowed to fly VFR above 5500 FT MSL in The Netherlands) which produces ca. 155 kts TAS. However at 65% I need to run the engine min. 50° F ROP and I have a total fuel consumption of 8.7 US gals or 33 Liters per hour from T/O to landing (18.8 US gals total) with a total flight time of 2:12 hrs (no wind).

If I would run on say 60% power (ie. 20" MAP and 2350 RPM at say 5000 FT) I would lose ca. 5 kts TAS however I could run the engine at peak EGT and I have a total fuel consumption of 7.9 US gals or 30 Liters per hour from T/O to landing (18.0 US gals total) with a total flight time of 2:17 hrs.

So I´d save 1 or maybe 1.5 US gals in the real life vs. a trade off of a 5 minutes longer flight time. After having made this assumptions I indeed came to the conclusion this is all just academic ... and decided just to enjoy flying the -4 (which is priceless).

Yes, these planes are fast and very much economic - however just f*@k the last couple of kts and let´s just enjoy what we are doing with these planes which is being proud of them and having fun!! As well I am encouraged to explore some other corners of the flight envelope like Smokey is suggesting ie. how would it be just cruising along with the speed of a Piper Arrow however just using 5 US gals instead of 10+ US gals or practise approaches with 60 kts IAS.

FWIW, Heinz
 
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Heinz, thanks for the post. With all the 180hp / 200hp CS prop posts here, I always feel like granny in the slow lane. My RV-8 is 150hp and a wood prop. (I think there should start a club for 150hp RVs :) )

I too recently did a performance chart and my numbers are very very close to yours. I also like we captured nearly all th same data points (albeit I have the classic bank of round gauges). The place we deviate is that I seldom fly any distance below 7500ft and often higher so at "old school" ROP, my fuel burn is somewhat less than yours.

And "yes", flying an RV is priceless :)

Thanks again for the details on your plane and flight data!
 
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european trip

Just about the same as I had this spring. We flew from Norway to Friedrichshafen(EDNY), via Bad Hersfeld (EDEN) Roskilde (EKRK), Denmark. Average fuel consumption was 32 liter (8,5 gal) and typical 5000ft AMSL showing 135-140kts IAS at 2350-2400rpm. This is also 160hp and a three blade fixed Catto. On the way back we did Prague and Berlin before we took a two leg from Berlin(EDAZ) to ENHA Norway via ESTA, Sweden. A total of 4:30 hours. It was a tough day. http://ln-rhv.blogspot.com

Also showed 165kts IAS @ 2600rpm at 1350 ft AMSL when doing passes for the noice certification.
 
60% data from another 2 flights

Hi,

I had to do this: I flew to take another set of data at 60% power and peak EGT and to see a friend (2 legs at each 142 NM).

The outbound leg I flew at 7500 FT MSL with a bit of tailwind (ca. 170 kts ground speed) and the leg back at 4000 FT MSL with ca. 135 kts ground speed and a bit of head wind still (however each leg at 60% power and peak EGT).

This is what I got:

2vvq4up.jpg


The interesting thing is that at 60% power and peak EGT I got as an average fuel consumption from T/O to LDG on both legs combined just ca. 7.25 US gals or or 27.5 Liters per hour vs. say 8.72 US gals or 33 Liters per hour at 65% power and 50° F rich of peak.

That is a saving of nearly 5.5 Liters or ca. 1.45 US gals per hour for giving in on ca. 5-7 kts TAS which I find something intersting to know. On my 330NM trip to the UK with no wind this would mean I´d travel ca. 7 mins longer .... no big deal really and the fuel saving of say ca. 3 US gals per leg might be worth it actually (see calculations below).

At German AVGAS fuel prices (ca. EURO 2.50 per Liter or nearly 13 USD per gal - believe it or not) this a considerable saving of ca. EURO 13.75 or ca. 18.50 USD per hour. Something to think about re the hourly price of flying if you fly ca. 70 hrs per year like I do. However or maybe still if you take all other costs like hangar, insurance and maintenance into account everyone needs to decide for himself if this neglectible or not.

Promise :p: I will NOT do any other performance run indeed as this can turn into nit picking (or as we say ´mosquito f**ing´- excuse my French).

Best, Heinz
 
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