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02-03-2011, 09:50 AM
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Join Date: Nov 2007
Location: Reno, NV
Posts: 2,125
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Quote:
Originally Posted by Alan Carroll
...Also, a few of the entries may not have had been using full power.
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Say it ain't so!  Actually F1Boss has been sandbaggin' a bit in Pesky. Wait till he runs with the new scoop he's fabbing this winter for his IO-550 (looks cool too!). First-time racers also sometimes go light to get a feel for racing, but that gets cured pretty fast when the bug bites!
Quote:
Originally Posted by Alan Carroll
...You can tell the serious racers because their throttle levers are slightly bent from being pushed forward 
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Or their throttle brackets (side-by-sides) are bent towards the firewall!  (AMHIK)
Quote:
Originally Posted by Alan Carroll
...The actual race results are maybe a better indicator of airframe improvements? For example Bob Axsom has climbed significantly in the results due to his many modifications.
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Very true! Bob, John Huft and Tom Martin are great examples. Some newcomers are doing great things too, and more will follow...and hopefully we'll see some more 390's running in RV Gold this year!
Fun stuff...back to my fiberglass work!
Cheers,
Bob
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02-03-2011, 07:50 PM
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Join Date: Mar 2005
Posts: 5,685
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Mostly correct but ...
Quote:
Originally Posted by elippse
I...
I assume these are numbers from the SARL races which are conducted most times at altitudes below 4000'. If we use Jim Smith's 197 mph average of three flights at 4000' dalt on his 150 HP, his FOM would be 37.08, not too shabby!
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Paul, These are all of the flights in all of the SARL races ever sanctioned including the AVC from the beginning of SARL in 2007. When the AirVenture Cup is flown out of Mitchell SD to Oshkosh (2008 and 2010) the altitudes vary widely from airplane to airplane. 17,500 ft. has been mentioned but not verifiable.
Bob Axsom
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02-04-2011, 07:41 AM
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Join Date: Feb 2007
Location: colorado
Posts: 873
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altitude of 2008 AVC
I ran the 2008 AVC at 11,500 for a good part of the race and at reduced power due to light rain ( wood prop). That resulted in the 214mph speed for the RV-4 red class. I am happy when I can break 200mph in any race.
With more races this year in different parts of the country, I will be curious to see if there are more and different airplanes than the "regulars".
One airplane that is curiously absent from the records is the Swift??
Chris M RACE34
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02-04-2011, 08:52 AM
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Join Date: Jul 2006
Location: Vul, VA
Posts: 316
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Quote:
Originally Posted by Alan Carroll
Here's another way to slice the onion; I took Bob's spreadsheet and worked out average race speeds for all aircraft types that had at least 5 races. The idea is to reduce the effects of differing wind conditions on the results. It should be noted however that there is a lot of variance being averaged here. I wouldn't take the numbers too literally but they make for some interesting comparisons.
Some general observations:
1. There seems to be no real difference in average speeds between the nosewheel vs. tailwheel side-by-side airplanes.
2. The RV-8 seems to be ~10 mph faster than the side-by-sides. Some of the RV-8s were running with 200 hp, but actually the fastest in this category had 180 hp. There seem to be more 180 hp than 200 hp entries.
3. The RV-8 Gold category seems to be 10-15 mph faster still. This includes the IO-390's plus John Huft (who according to his website has 223 hp, and has done a lot of airframe work).
4. Not surprisingly the 6-cylinder RVs/Rockets are faster than the 4-cylinder RVs.
5. The only factory ships that kept up with the RVs were the Bonanzas.
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Was the turbine legend omitted because it did not have five races?
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02-04-2011, 09:08 AM
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Senior Curmudgeon
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,420
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I tend to agree, the chart would be much more telling if broken down by engine--------size and HP.
__________________
Mike Starkey
VAF 909
Rv-10, N210LM.
Flying as of 12/4/2010
Phase 1 done, 2/4/2011 
Sold after 240+ wonderful hours of flight.
"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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02-04-2011, 09:18 AM
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Join Date: Dec 2006
Location: Arroyo Grande, CA
Posts: 938
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Quote:
Originally Posted by Bob Axsom
Paul, These are all of the flights in all of the SARL races ever sanctioned including the AVC from the beginning of SARL in 2007. When the AirVenture Cup is flown out of Mitchell SD to Oshkosh (2008 and 2010) the altitudes vary widely from airplane to airplane. 17,500 ft. has been mentioned but not verifiable.
Bob Axsom
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That's very true, Bob, which makes it really difficult to do any kind of comparison without having a correstion factor for density altitude. From what I've read, though, about the altitudes that are flown on these closed courses, the Oshkosh race aside, I would assume that when I said that 4000' would probably be a reasonable comparison value, that would still be in the ballpark.
But in any closed-course race, the planes will never attain their flat out speeds. When doing planning for Reno, I typically use about a 10 mph deficit against straight and level for planes in the 200-250 mph category. But they're having to fly a race-course shaped pattern where the end curves are actually composed of several pylons. The triangular courses in SARL are not as demanding, so I would guess that because of turns, winds, and planning, the SARL deficit would be more in the vicinity of 5 mph.
I really should have used that in calculating Jim's FOM, which would be more like 36.1 instead of 37.1. But since a change in speed with horsepower is proportional to the cube-root of the HP change, using a figure of merit such as speed/HP^1/3 gives a really good look at the overall efficiency of any given plane. It can really show the differences between two planes of the same type and HP.
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02-04-2011, 11:02 AM
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Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,544
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Based on Paul Lipps formulae, speed/HP^1/3, my aircraft has a rating of 40.11 which I guess is pretty good! This calculation is based on an assumed HP of 300 and an average race speed of 268.73 mph for the 2010 race season.
__________________
Tom Martin RV1 pilot 4.6hours!
CPL & IFR rated
EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
RV14 Tail dragger
Fairlea Field
St.Thomas, Ontario Canada, CYQS
fairleafield@gmail.com
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02-04-2011, 01:41 PM
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Join Date: Jul 2007
Location: Madison, Wisconsin
Posts: 778
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Quote:
Originally Posted by prporter
Was the turbine legend omitted because it did not have five races?
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Yes. There are a couple of speeds listed in Bob's spreadsheet; Marty Abbot's Garrett-powered Legend had the highest overall speed of any of the races I believe (401 mph).
__________________
Alan Carroll
RV-8 N12AC
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02-04-2011, 02:46 PM
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Join Date: Dec 2006
Location: Arroyo Grande, CA
Posts: 938
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Quote:
Originally Posted by Tom Martin
Based on Paul Lipps formulae, speed/HP^1/3, my aircraft has a rating of 40.11 which I guess is pretty good! This calculation is based on an assumed HP of 300 and an average race speed of 268.73 mph for the 2010 race season.
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That is very good, Tom! Congratulations on having such an efficient airframe-engine-propeller combo!
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02-04-2011, 06:59 PM
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Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,393
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speeds
To me it seems that Bobs original post gives more pertinent information. Huft did 249 with the RV8 and Anders did 240 with the RV4. There are no Rockets listed as category winners. Anders in the CAFE performance test devastated the HRII by such a large margin that the numbers will stand for a long time.
The Wittman Tailwind is an interesting study. In 1953 Wittmans original Tailwind with a hot rod 85 hp Continental would outrun a Bonanza which then had 185 hp. Today the W10 Tailwind with 0 320 Lyc will outrun the 285 hp V tail Bonanza. Progress??? Not much on the part of Beechcraft.
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