F

flynwest

Well Known Member
I have a 8 with the Barrett IO 390 and the 200RV prop. My friends all want to know how fast it is, I always say fast enough. They want to know with all the controls forward how fast? The only time it is full forward is on take off. I usually cruise at 23 square and see 180 knots With all forward it will probably go past vne?

My question to all the hot rod guys is will it be fastest with alll controls forward or should the mixture be 100 ROP and the Prop back some or 2700 RPM's and full rich. And how fast is safe in smooth air. What do you think?

Thanks in advance for the advise. Dan West
 
I raced my -10 this Spring..

...on a 145 mile, 4 leg race course. I had asked Barrett at Sun 'n Fun if I could run the engine WOT for 45 minutes and he said that I could run WOT for the life of the engine and wouldn't hurt it:eek:

He then went on to say that there may be a more optimal RPM number for best speed besides 2700, so I experimented on the way over there and found that 2640 increased my speed almost 2 MPH according to the Dynon...just a little more bite in the prop.

FWIW, I went on to set top time of day at 211MPH...exactly what Van says.

Best,
 
RV-8 fast

If you go to www.sportairrace.org and scroll down the page toward the bottom you will find links to every plane in every race for the past four years. If you scan through them you can see all of the speeds for every RV that has raced. The fastest is John Huft he has a modified "360" that he now flys in the RV-Gold class (with the 390s) to give the RV-Blue class (360s) a little relief. Deane Ogden flies a RV-8 with a 390 in the RV-Gold Class. So their numbers may be what you are looking for. How you fly your plane is your responsibility but I doubt these guys are holding anything back. John's top speed was 217.17 kts in the 2008 (tailwind) AirVenture Cup race but his normal top speed is around 201 kts. Deane's speeds are a little slower.

Bob Axsom
 
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Just flew some ASI calibration runs per the NTPS method. Mine is also an IO-390 powered RV-8, but I'm using a Hartzell BA. "All handles full forward" was 197.8 knots true at 2500 MSL. Nothing was taped, no CG shifting, and I have not yet squeezed down the cooling exit per plan....just a baseline.

There is probably some speed in tweaking mixture and prop, but be cautious. Lycoming has not yet published an IO-390 power chart with a detonation limit line. As I recall, Dick Martin found it the hard way once.
 
flynwest said:
I have a 8 with the Barrett IO 390 and the 200RV prop. My friends all want to know how fast it is, I always say fast enough. They want to know with all the controls forward how fast? The only time it is full forward is on take off. I usually cruise at 23 square and see 180 knots With all forward it will probably go past vne?

My question to all the hot rod guys is will it be fastest with alll controls forward or should the mixture be 100 ROP and the Prop back some or 2700 RPM's and full rich. And how fast is safe in smooth air. What do you think?

Thanks in advance for the advise. Dan West
Click to expand...

Tell them whatever you want! Do they own airplanes? Add 5 knots to whatever their fastest speed is! :D
 
Dan (W),

Good questions, and its good to see Dan (H's) numbers too...I've been wondering, and will continue to watch your experiments with much interest Dan. Hope you'll come out and play in SARL, as you'll be a real competitor in RV Gold (and its fun stuff!).

Dan (H) also gives good advice on the mixture. Since you're in Sacto, you can test down fairly low. As Dan said, don't lean much at full power at low altitude. I've been trying to figure out how much I can lean at sea level races, and have only come back a turn or two, watching the EGT and CHT. I keep them in the mid 1300's and 390's respectively...but don't take that as gospel...in fact I do seek feedback on those numbers, and its variable...mostly good, with the caveat that temps are a bit subjective due to probe placement and differences...usually seen as a relative number. Not sure I have seen any real speed gains from minor leaning, and rich = cooling at high power, so I shoot for that side of things. All FWIW!

Good news is that you probably won't run into Vne issues down low and flying level. Do be careful if you go up high to test...watch the TAS, and be cautions of full power decents....TAS can creep up fast.

Pick a calm day (better for data and Vne comfort level) and run the NTPS GPS test runs, low and level (I just run 4 cardinal headings for ease of flying...its just one method). Run it full BTTW for cooling and see what ya get. Its a fun test hop. Calibrates your ASI and gives you an idea of what you'll run flat out! LAter runs can be experiments with RPM, and it would be interesting to see if lower RPM increases speed...haven't tried that test yet.

And then...c'mon out to Wenatchee and run the Great Northwest Air Race (laid back race) and "calibrate" it some more! We didn't have an RV Gold racer in that race last year! ;)

Lemme know if you want a chase plane on your side of the hill...won't take much arm twisting!!

Cheers,
Bob
 
Here are the RV-8 Speeds from SARL records

I extracted the RV-8 speeds from the SARL records and printed them below. The information includes the speed rank, the race, the date, the class, the airplane, the pilot, and the speed in knots respectively. The first number in each row is the rank of the speed relative to all speeds in all SARL races and the last number is the speed in knots.

161 AirVenture Cup 2008 7/28/08 RV Blue RV-8 Huft, John 217.17
207 Rocket 100, 2010 11/20/10 RV Gold RV-8 Huft, John 207.43
213 AirVenture Cup 2007 7/23/07 RV Blue RV-8 Huft, John 204.56
223 AirVenture Cup 2008 7/28/08 RV Blue RV-8 Ross, Jon 202.59
224 AirVenture Cup 2010 7/26/10 RV Gold RV-8 Huft, John 201.97
225 Grace Flight 2009 10/4/09 RV Blue RV-8 Huft, John 201.71
227 Taylor 100 2009 3/16/09 RV Blue RV-8 Huft, John 201.29
228 AirVenture Cup 2008 7/28/08 Sport FX RV-8 Martin, Dick 202.28
230 Pagosa Springs 2010 9/26/10 RV Gold RV-8 Huft, John 200.93
238 Colorado 150, 2008 6/29/08 RV Blue RV-8 Huft, John 199.27
239 Pagosa Springs 100 2009 9/27/09 RV Blue RV-8 Huft, John 199.38
241 Rocket 100, 2010 11/20/10 RV Gold RV-8 Ogden, Deene 198.85
250 Rocket 100 2008 11/23/08 RV Blue RV-8 Huft, John 197.43
252 Rocket 100, 2010 11/20/10 RV Blue RV-8 Rovey, Jason 197.38
254 Texoma 100 4/25/10 RV Gold RV-8 Ogden, Deene 197.15
259 Rocket 100, 2010 11/20/10 RV Gold RV-8 Hajek, Jerry 196.36
263 Rocket 100, 2007 11/18/07 RV Blue RV-8 Huft, John 194.78
265 Sulphur Springs 130 7/18/10 RV Gold RV-8 Ogden, Deene 194.59
268 AirVenture Cup 2007 7/23/07 Sport FX RV-8 Martin, Dick 194.36
270 AirVenture Cup 2008 7/28/08 RV Blue RV-8 Carroll, Alan 193.76
272 Tennessee Valley Air Race 2010 10/30/10 RV Blue RV-8 Rovey, Jason 193.5
275 Texoma 100, 2008 4/20/08 RV Blue RV-8 Christman, Dave 192.88
283 Tennessee Valley Air Race 2010 10/30/10 RV Blue RV-8 Carroll, Alan 192.07
285 AirVenture Cup 2007 7/23/07 RV Blue RV-8 Ross, Jon 192.04
288 AirVenture Cup 2007 7/23/07 RV Blue RV-8 Carroll, Alan 191.77
296 Rocket 100, 2010 11/20/10 RV Blue RV-8 Grover, David 189.26
297 AirVenture Cup 2009 7/27/09 RV Blue RV-8 Huft, John 189.13
300 AirVenture Cup 2010 7/26/10 RV Blue RV-8 Ross, Jon 189.01
301 Taylor 100 2009 3/16/09 RV Blue RV-8 Carroll, Alan 188.96
302 Great Canadian Air Rally 2010 8/22/10 RV Blue RV-8 Carroll, Alan 188.83
303 Taylor 150 4/11/10 RV Gold RV-8 Ogden, Deene 188.69
307 Taylor 100 2009 3/16/09 RV Blue RV-8 Christman, Dave 188.33
310 Sulphur Springs 130 7/18/10 RV Blue RV-8 Rovey, Jason 188.12
311 West Texas 100 6/6/10 RV Gold RV-8 Huft, John 187.99
317 AirVenture Cup 2008 7/28/08 RV Blue RV-8 Schryver, Fred 187.49
323 Pagosa Springs 2010 9/26/10 RV Blue RV-8 Rovey, Jason 186.47
327 Grace Flight 2010 10/2/10 RV Blue RV-8 Carroll, Alan 185.7
329 Texoma 100 4/25/10 FAC1RG RV-8 Slocum, Scott 185.49
331 Grace Flight 2010 10/2/10 RV Blue RV-8 Rovey, Jason 185.32
339 Grace Flight 2010 10/2/10 RV Blue RV-8 Chrisman, Dave 184.94
341 Grace Flight 2010 10/2/10 RV Gold RV-8 Ogden, Deene 184.86
342 AirVenture Cup 2007 7/23/07 RV Blue RV-8 Jordan, Scott 184.85
343 AirVenture Cup 2007 7/23/07 RV Blue RV-8 Schryver, Fred 184.85
363 Pagosa Springs 2010 9/26/10 RV Blue RV-8 Taylor, Craig 183.31
368 AirVenture Cup 2010 7/26/10 RV Blue RV-8 Carroll, Alan 182.98
381 Rocket 100, 2010 11/20/10 ? RV-8 No Name 181.53
384 Colorado 150, 2008 6/29/08 RV Blue RV-8 Carroll, Alan 181.34
391 Texoma 100 2009 5/31/09 RV Blue RV-8 Tuckey, Pat* 180.59
393 AirVenture Cup 2009 7/27/09 Sport FX RV-8 Martin, Dick 180.44
392 AirVenture Cup 2009 7/27/09 RV Blue RV-8 Ross, Jon 180.44
408 West Texas 100 6/6/10 RV Blue RV-8 Rovey, Jason 179.91
413 Pagosa Springs 100 2009 9/27/09 RV Blue RV-8 McCann, Jim 179.42
419 Rocket 100, 2010 11/20/10 RV Red RV-8 Jones, Bryan 179.03
457 Pagosa Springs 2010 9/26/10 RV Blue RV-8 Crosley, Eber 177.21
462 AirVenture Cup 2009 7/27/09 RV Blue RV-8 Carroll, Alan 176.87
469 Top of the Chesapeake 7/11/10 RV Blue RV-8 Robertson, Gordon 176.38
508 Pagosa Springs 2010 9/26/10 RV Blue RV-8 Greenberg, Redge 173.42
516 Texoma 100 4/25/10 RV Blue RV-8 Stanton, Danny 173.1
561 Taylor 100 2007 5/20/07 RV Red RV-8 Jones, Bryan 169.45

Bob Axsom
 
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Bob Axsom said:
I extracted the RV-8 speeds from the SARL records and printed them below. The information includes the speed rank, the race, the date, the class, the airplane, the pilot, and the speed in knots respectively. The first number in each row is the rank of the speed relative to all speeds in all SARL races and the last number is the speed in knots.
Click to expand...
These are race speeds so are ground speeds and not TAS. Lets not mix them, please.
 
These are race speeds so are ground speeds and not TAS. Lets not mix them, please./QUOTE]

Yes these speeds are ground speeds, not TAS, but with the exception of the AirVenture Cup Races they are closed loop races which tends to negate the effects of wind. Many of the races, Memphis, Courtland, Taylor, to name a few are quite low, relative to sea level, and at sea level TAS is supposed to be pretty close to IAS, depending on temperature and pressure.
Regardless, these are the only real numbers that we have available, and as such they are entirely valid in terms of answering the original question in the spirit that it was asked.
Click to expand...
 
Good information guys and thanks for the offer of wing and the results. I may have time today to test 4 way speed I'll post results. Thanks again. Dan
 
Tom Martin said:
Regardless, these are the only real numbers that we have available, and as such they are entirely valid in terms of answering the original question in the spirit that it was asked.
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Do not get me wrong, I think those are great numbers and wish my RV was as fast as these. SARL is an excellent challenge and would like to participate if time allowed. It is a great way to see how fast you are against others (actually the only true way to do it as any other way is fret with instrumentation errors and uncertainties).
I just do not quote ground speed for how fast is fast. I have been over 220 kts ground speed in my RV but I never quote that number. I always quote Vne or 182 kt TAS as I have obtained that number.
Click to expand...
 
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Tom Martin said:
These are race speeds so are ground speeds and not TAS. Lets not mix them, please./QUOTE]

Yes these speeds are ground speeds, not TAS, but with the exception of the AirVenture Cup Races they are closed loop races which tends to negate the effects of wind. Many of the races, Memphis, Courtland, Taylor, to name a few are quite low, relative to sea level, and at sea level TAS is supposed to be pretty close to IAS, depending on temperature and pressure.
Regardless, these are the only real numbers that we have available, and as such they are entirely valid in terms of answering the original question in the spirit that it was asked.
Click to expand...

Ditto what Tom said. I also calculated average race speeds for the RV-8 from Bob Axsom's table and found the following:

197 knots for RV-8s with more than 200 hp (20 race times)
185 knots for RV-8s 200 hp and less (37 race times)
189 knots for all RV-8s (57 race times)

The first number actually seems to agree pretty well with what Dan Horton reported for TAS. The second number is slightly below what Van's reports for top speed with 180 hp, but probably within error. The races are usually timed from the takeoff roll, have multiples turns, etc, which adds to the times. Its also possible that some of these runs weren't at full throttle. The difference between the two groups (12 knots) probably due mostly to higher power?

Not a substitute for GPS TAS measurements but an interesting data point.
Click to expand...
 
SARL Race Locations for 2011

Phillip,

Maybe next year you could make it to one of the races (see schedule below). Indianapolis, Indiana, Courtland, Alabama or Sherman, Texas might work for a one day trip from St. Louis but and overnight stay before the race is easier on the pilot. You might check with Dave Adams who flies his Long EZ from St. Louis to many races.

Bob Axsom

Races Scheduled For 2011
These are SARL-sanctioned races where
placing will accumulate points towards
your League total.

The Taylor 125 Air Race
2 April, 2011
Taylor, TX (T74)

The Texoma 100 Air Race
16 April, 2011
Sherman, TX (GYI)

The Big Country Air Fest and Air Race
30 April, 2011
Abilene, TX (ABI)

The Lone Star 150 Air Rally
14 May, 2011
Galveston, TX (GLS)

The Mesquite 130 Air Race
28 May, 2011
Mesquite, TX (HQZ)

The West Texas 100 Air Race
18 June, 2011
Plainview, TX (PVW)

The Great North West Air Rally II
18 June, 2011
Wenatchee, WA (EAT)

The Top Of The Chesapeake Air Rally II
9 July, 2011
Elkton, MD (58M)

Air Venture Cup
24 July, 2011
Dayton, OH (MGY)

The Indy Air Race
13 August, 2011
Indianapolis, IN (field TBD)

The Great Candian Air Rally II
27 August, 2011
St. Thomas, Canada (CYQS)

The Tennessee 100 Air Race
10 September, 2011
Tullahoma, TN (THA)

The Pagosa Springs 100 Air Race
24 September, 2011
Pagosa Springs, CO (PSO)

The Thunderbird 100 Air Race
8 October, 2011
Holbrook, AZ (P14)

The Houston 150 Air Race
15 October, 2011
Cleveland, TX (6R3, LFK alternate)

The Tennessee Valley Air Race IV
29 October, 2011
Courtland, AL (9A4)

The Rocket 100 Air Race
19 November, 2011
Taylor, TX (T74)
 
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flynwest said:
My question to all the hot rod guys is will it be fastest with alll controls forward or should the mixture be 100 ROP and the Prop back some or 2700 RPM's and full rich.
Thanks in advance for the advise. Dan West
Click to expand...

This is exactly what your phase 1 is for.
Your engine/prop/plane combination is unique. It should be tested.
 
If You are really interested in speed

It is really important to get a absolutely reliable baseline speed using the best test method you can in the initial configuration. The baseline speed is what you will measure all of your future work against and all future test flights for evaluating speed improvements need to be flown exactly the same way. My baseline speed in our RV-6A is 170.67 kts. Every test flight of mine is three legs flown at 6,000 ft. density altitude according to the old USAR handicapping procedure - I climb to 6,000 ft with altimeter set to 29.92; check OAT; if it is 3C fly the test there; if it is higher I descend 100 ft for each degree C above 3 and fly the test there; if it is lower I climb 100 ft for each degree C for each degree below 3 and fly the test there; I push push the throttle and prop full forward; lean the mixture for best speed (around 100 F egt rich of peak), trim for hands of level flight; fly 360 GPS ground track and when the speed settles down record them every 20 seconds until five consecutive speed recordings are within one knot; I turn to a 120 degree GPS ground track and repeat the speed test for that leg; then I turn to a 240GPS ground track and repeat for the final leg which completes the test (usually at this point I record all CHTs, EGTs, RPM, oil temp, oil pressure, and any other observations befor throttling back). On the ground I avarage the 5 speeds for each leg and enter them into the National Test Pilot School spread sheet with the GPS ground tracks and it tells me the KTAS as well as wind direction and speed. Initially I hand flew but now I lock in the ground track and altitude with the trutrac autopilot for greater accuracy.

Bob Axsom
 
Fast Cost alot a fuel

Well I went out today and flew all hanles forward 4 directions average 195 knots rpm was just 2660. I will do it again when the weather settles down using the info Dan H. sent. Thanks for that Dan. Need to own stock in and oil company, 19.5 gph ouch. I guess it's the old saying speed cost money how fast do you want to go.
 
The slogan of...

flynwest said:
Well I went out today and flew all hanles forward 4 directions average 195 knots rpm was just 2660. I will do it again when the weather settles down using the info Dan H. sent. Thanks for that Dan. Need to own stock in and oil company, 19.5 gph ouch. I guess it's the old saying speed cost money how fast do you want to go.
Click to expand...

Cotton Owens' NASCAR race shop was "Where money buys speed." :)

LarryT
 
Thanks Bob I did not do it like that I just recorded the speed and checked egt/cht/gph and did not lean. I think 6000 feet will be better base line because I can lean to 100 rop, that may get the fuel flow down also. Thanks again for all the info. great stuff. I need to live in Texas to race looks like they have most races there.
 
A little cost savings on speed test

NTPS has two spreadsheets one for three legs and one for four legs. It takes a while to fly each leg so the 3 leg approach saves time and money without any demonstrated lack of accuracy. As Kevin Horton told me years ago and I have since proven to myself, the straight average approach of multiple leg speed testing always errors on the side of underestimating the speed of the airplane under test.

Axel is working with SARL to organize a race in California. I'm not sure when or where but he is serious about it and several of the SARL folks like Bob Mills have volunteered their assistance. It could happen.

Bob Axsom
 
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