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Join the Fastest TAS Club

n700jl

Well Known Member
Hello RV Friends! Many years ago i brought you the Join the 200kt Club. Many of our fellow RV pilots joined the club and showed us just how incredible these airplanes are. They also show us some fantastic airmanship by selecting the perfect altitude for getting the 200kts GS. Now lets up the game. I want to see and I know that you do to, those TAS numbers straight and level! Bring those power levels all the way forward(just keep it under VNE)! Have fun be safe and show us what you have. This should be fun, plus this is very informative. :D
 
Calcluating TAS

Should be fun.

I think I'll need to use the GPS method for calculating this, rather than just reading it off the EFIS. My builder put temperature probes in the NACA vents, and they appear to read much higher than real OAT, which (if I remember correctly) goes into the EFIS's TAS calculation.
 
difference is small, I think

Should be fun.

I think I'll need to use the GPS method for calculating this, rather than just reading it off the EFIS. My builder put temperature probes in the NACA vents, and they appear to read much higher than real OAT, which (if I remember correctly) goes into the EFIS's TAS calculation.
if the online calculators are to be believed, it seems like 5c of temperature difference shows a couple of knots higher/lower. Do you feel OAT at the wingtip and OAT in the NACA will be more than 5c of difference?
 
I would think that the venturi effect of a NACA duct would make temperature readings there unreliable, although I'd expect them to be lower than OAT.
 
183KTAS straight and level.
2003 RV-7
IO-360 w/ one mag, one LSE
WW 200RV CS prop
Can’t seem to get a single knot more out of her. :)
 
I would think that the venturi effect of a NACA duct would make temperature readings there unreliable, although I'd expect them to be lower than OAT.
I think the assumption is that engine heat might affect the OAT measurement. I have not done any comparison so I not sure if this is correct or not, but I'm sure someone here has done this. I can't imagine it being more than 5-10c, which seems to translate into a few kts of TAS difference.
 
It's not hard - down low I can hit Vne with my airplane, of course I'm running the 360 and a constant speed. I've only done that twice, once during testing and once afterward, I generally don't fly low.
 
temp probes in the wrong spot

The other day my EFIS said the OAT was 64F, and it couldn't have been over 35F out there. Probably lower. That's the biggest difference I've seen, but it's not atypical.

I think the effect is due to warmth from the engine. And there's probably not a huge countervailing venturi cooling effect, especially in the winter, because I plug the leaky plastic vent up on the cabin side.

This whole thing likely didn't worry the builder any because he was in Texas, and presumably spent a lot of time flying when the OAT was hotter than the engine....

I'd agree it likely doesn't make a HUGE difference. My GPS groundspeed seems to match up pretty well with my TAS minus the EFIS-calculated headwind component, but again that entire calculation is presumably a bit suspect.

Obviously I still think I have the fastest -9A on Earth and will attempt to verify this with GPS and mathematics only, assuming somebody else handles the math. :)

I think the assumption is that engine heat might affect the OAT measurement. I have not done any comparison so I not sure if this is correct or not, but I'm sure someone here has done this. I can't imagine it being more than 5-10c, which seems to translate into a few kts of TAS difference.
 
Hi Jon

This as stupid as the "200kt Club" which you brought to us :(

There is only one way to compare speed between RVs (ok, maybe with other contenders as well), and this is head to head, shoulder to shoulder, side by side, WOT, on the same day/altitude/humidity/time/etc.

Anything else is just conspicuous myth :D
 
I would think that the venturi effect of a NACA duct would make temperature readings there unreliable, although I'd expect them to be lower than OAT.

It is a possibility that the temp is slightly higher in the Naca vents due to Ram Rise. Although I am not sure it would be significant enough at these speeds. Not sure how much the airflow is accelerated through the vents.

Someone on the forum will surely know.

Ram Rise:

https://www.pittspecials.com/articles/RamAirTempRise.htm
 
Hi Jon

This as stupid as the "200kt Club" which you brought to us :(

There is only one way to compare speed between RVs (ok, maybe with other contenders as well), and this is head to head, shoulder to shoulder, side by side, WOT, on the same day/altitude/humidity/time/etc.

Anything else is just conspicuous myth :D

I’m all in for drag racing! RV6-A 155kt GS /150kt IAS. Long EZ was 154kt GS.
 

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Hello RV Friends! Many years ago i brought you the Join the 200kt Club. Many of our fellow RV pilots joined the club and showed us just how incredible these airplanes are. They also show us some fantastic airmanship by selecting the perfect altitude for getting the 200kts GS. Now lets up the game. I want to see and I know that you do to, those TAS numbers straight and level! Bring those power levels all the way forward(just keep it under VNE)! Have fun be safe and show us what you have. This should be fun, plus this is very informative. :D

Here's a shot of my RV-10. I did this a week or so ago. Some on the FB RV-10 list doubted the EFIS readouts, but I verified things by doing the triangle 120, 240, 360 degree deal and averaged the speeds. If anything it' reads a few knots slower than the GPS ground speed........ Keep in mind that this was lean of peak EGT operations! Next joyride, I will run the RPM up and see what I can actually max out at while cruising 7500 feet:).....Also, my OAT probe is out on the wing (in ambient air) out of the way of the heat of the engine cowl and exhaust.
 

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Literally off the back of an envelope:
at 200 mph, pressure rise ~5%, temp rise ~1.3% or
~7 degrees F.
I don't know what venturi effect is with an air scoop.
 
Likely MPH and likely Ground Speed. Apples to oranges

Sounds like a good shot of sour grapes too. If you could come close to that, I wager you'd be in Reno as well.

The speeds are mph, and they are ground speed, averaged around the course so wind is not a factor.
 
Hi Jon

This as stupid as the "200kt Club" which you brought to us :(

There is only one way to compare speed between RVs (ok, maybe with other contenders as well), and this is head to head, shoulder to shoulder, side by side, WOT, on the same day/altitude/humidity/time/etc.

Anything else is just conspicuous myth :D

A bit harsh, but well then, just pick an altitude (let's say 7500 feet PA-everyone dial in 29.92), and then the only variable would be the OAT. That would reduce most of the variables. Otherwise I'm up for a head to head, shoulder to shoulder run-off:).......
 
That's a pretty slow Long-EZ

I’m all in for drag racing! RV6-A 155kt GS /150kt IAS. Long EZ was 154kt GS.

To be fair, that's a fairly slow Long-EZ. The fastest one is Klaus, who clocked 258.65 MPH at the 2019 AirVenture Cup. The typical Long-EZ/Cozy folks that year were at 205-225 MPH. Only the O-235 EZ drivers folks were down at 160-190 MPH.
 
I've seen 200kt TAS just above the 1000'MSL runway burning 17.8gph. I've seen 177TAS at 13.5k' at 7.8gph, LOP and 2350RPM. Haven't tried flat out at altitude.

Ed Holyoke
RV-6
 
Lighten up!

Hi Jon

This as stupid as the "200kt Club" which you brought to us :(

There is only one way to compare speed between RVs (ok, maybe with other contenders as well), and this is head to head, shoulder to shoulder, side by side, WOT, on the same day/altitude/humidity/time/etc.

Anything else is just conspicuous myth :D

DeeCee 57. Thank you so much for making VAF a great place for information. I am sorry that you think my post are stupid. Many other RV pilots have enjoyed seeing my 200kt GS club post, with 347 replies and over 166500 views I would say that is pretty good. I have meet RV pilots at Oshkosh from all over the world that have commented on how they enjoy VAF and seeing just how fast we can go with the 200kt club! This is about education and recreation, not slamming our fellow pilots. I hope others will enjoy and be educated by these post on this website. So in other words if you cant say anything nice keep your thoughts to yourself. Have a wonderful day!
 
Fun Stuff!

... I like your post! This was my last trip to Oregon. Not too bad for an RV-9A
160 HP. @ 7 GPH...:rolleyes:

 
hey Jon, hold on your horses ;)

I sure, as zillions others do, agree on the purpose of VAF :)
And good for you if another zillion appreciate your "clubs" :)

So in other words if you cant say anything nice keep your thoughts to yourself. Have a wonderful day!

Appreciate, wishing you the same wonderful day, sincerely meant.

PS
;) also means "cool down and relax man, no slamming intended"
 
Sounds like a good shot of sour grapes too. If you could come close to that, I wager you'd be in Reno as well.

The speeds are mph, and they are ground speed, averaged around the course so wind is not a factor.

Cool your jets Iceman. Was pointing out the difference of a Reno GS and the topic of this thread; TAS. Again, apples to oranges
 
clocked 258.65 MPH at the 2019 AirVenture Cup.

It's hard to trust any of the numbers from the 2019 AVC. I was the only RV Red so I won (yay) but they have my race time as ONE HOUR AND FIVE MINUTES SLOWER than I actually raced. The advertised speed was appropriate for the slow, incorrect time. I called a few people and asked, they admitted to a timing error (nice people) and updated my published speed (but not race time?). Not sure where the new average speed came from because it too is wrong. It's slower than one of the RV's in the bottom of the RV Blue class that I HAD PASSED.

Just my .02 on using the AVC numbers as a gauge... that's all
 
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RV4, O-360, Sensenich FP GA prop, turning 2700 at 1000’ AGL WOT: 185KTAS.
On my wing (left) was Ken Rieder (Redline 2, in Jon Thocker’s original), at 184 KTAS (IO-360, Hartzell Composite), and on my right wing was Austin Rieder (Ken’s son in Ken’s Redline 1, IO-360, Hartzell Composite) at 183 KTAS. All three ground speeds confirmed what we were seeing in the cockpit. Wide open on those two RV8’s is 3000 RPM, and I don’t think they were there. I think they were at 2700. Interesting thing is how close these airplanes are in performance. All three had similar engine displacement, and maybe power rating. If I had a 1K advantage, its because of my lighter weight and slightly different profile. My carburetor doesn’t make any difference as long as I can get the fuel to the engine to make the horsepower. Not as efficient in cruise (LOP), but that’s not what we’re looking at here. These are quick airplanes, no doubt.
 
Need to use GPS data

As others have suggested, I think you need to use GPS based data processed by something like the NTPS spreadsheet in order to produce reliable results.

https://www.kitplanes.com/flight-testing-finding-tas-from-gps-data/

Here is an example using the four-leg method, maximum available power on the deck (450' DA) in my RV-10. GPS data downloaded from the G3X, two minutes for each leg.

maxperformJan17.jpg

And here is a graph summarizing the results at different altitudes, KTAS, based on four leg NTPS analysis of GPS data.

maxperformsum copy.jpg
 
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This might work?



Checking the pic I uploaded. I swear I have seen 1KTAS faster, but danged if I can find that one. Headed home from Reno this trip...
 

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I want to see and I know that you do to, those TAS numbers straight and level! Bring those power levels all the way forward(just keep it under VNE)!

There are more than a few -8's which will run in excess of published VNE, straight and level. I'm sure of at least one ;)
 
thanks Dan.

and that is exactly why I used that adverb in post #9. It might have something to do with safety...
 
I saw 235 knots true on the EFIS yesterday at 60% power....but I’ll admit I was in a slight descent....and I was in the jet..... (that thing is SO slippery with the nose pointed down!) :)
 
I saw 235 knots true on the EFIS yesterday at 60% power....but I’ll admit I was in a slight descent....and I was in the jet..... (that thing is SO slippery with the nose pointed down!) :)

Well.......I saw 400 KTAS last night. But I admit that I was at 100% power in a not so slight dive..........and dreaming :)

Seriously, the fastest I’ve seen in the Rocket at 1500’ is 209 KTAS @90% power. That was at WOT and 2350 rpm. Might go a bit faster with a bit more revs.
 
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Non-RVs

If we're allowing aircraft other than RVs, we'll see some pretty high TAS numbers. There's some with military experience and supersonic aircraft in their logbook!
 
There are more than a few -8's which will run in excess of published VNE, straight and level. I'm sure of at least one ;)

I can tell you of at least one RV-3 that can do that as well, but I am certainly not going to publish a number...:rolleyes:
 
Closed Course Wind

Sounds like a good shot of sour grapes too. If you could come close to that, I wager you'd be in Reno as well.

The speeds are mph, and they are ground speed, averaged around the course so wind is not a factor.

Actually, wind is a factor on a closed course...but it only serves to slow down the average lap speed.

By the way, from 2017 on, the current Reno lap distance is the measured straight-line distance from pylon to pylon. Since the race aircraft are actually flying farther than the official lap distance the calculated lap speed numbers are conservative and the average TAS is bit higher.

Skylor
 
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208 MPH @ SNF on the deck when they had a timed triangle race course event. bone stock 6A, 0-360, fix pitch 85 inch, slick mags, alternator off, 2950 rpm.
DSC8070.jpg
what a blast.
 
Interesting ... I hadn’t considered this. :D

Any idea what switching the alt off is worth?

Depends upon the load. At 15 amps, I would speculate 2-3 HP. I am sure there are tables out there that list typical HP / load. My 4000 watt generator only has a 12HP engine, though that doesn't have the efficiency loss of AC -DC conversion.
 
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Checking the pic I uploaded. I swear I have seen 1KTAS faster, but danged if I can find that one. Headed home from Reno this trip...

Well, I just today took a shot at it and was able to match your speed of 214 KTAS, but down low it was more than DOUBLE your fuel flow. It's still a very dirty airplane though - there is quite a bit more speed in it.
 

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uh-oh!

Well, I just today took a shot at it and was able to match your speed of 214 KTAS, but down low it was more than DOUBLE your fuel flow. It's still a very dirty airplane though - there is quite a bit more speed in it.

LOL you found out that the Evo wing is made for higher altitudes, which means the Sport wing is faster down low! D'OH! I think the break-over point is around 7500MSL...so you gonna have to catch me as I'm climbing out!!

It's odd that I can see the same TAS while in a SARL race - maybe a wee bit more - but I can't hold it steady. SARL races are normally run as low as possible...except for the Pagosa Springs race.

Hmmmm...the climb rate comparison might be an interesting test.
 
Depends upon the load. At 15 amps, I would speculate 2-3 HP. I am sure there are tables out there that list typical HP / load. My 4000 watt generator only has a 12HP engine, though that doesn't have the efficiency loss of AC -DC conversion.

15amps at 14v is 210w or 0.29hp. Add an astronomical inefficiency and you're still less than 1hp consumed from the engine.
 
Jon (OP), Mark and Mike,

Here's some side-by-side fun (our photos side by side...and maybe a little play on words for bringing my Super Six into the mix with you Rocket Boyz...

Here's the photos (in this case, 3 of a kind at 214 EFIS TAS):

Mark's

88qY9wbHC_Z3sF6OeyS_YVW4_ENNkm98AUP5aE1qCvgdCdWicFU1kfin0GV8b23VzlLLwdNPwZ5nXP9GYg=w165-h220


Mike's

XbkjNj_pOYl4I5mfogm02iwey7-VtZFs16DYdbdBzqi3HwXWjhXCXNzSf401Yh2VPyFTDqBnCb6Ul4f4Mg=w256-h218


Mine:

T5eE2_ijdk32vTPkq6zm42mcHLdJPC3kIeX6JJzkZ_mG2021sZRfH9n1uHa5z5fb6nQWsO7NWZaAwHH-xQ=w293-h220


VzN3qSQYIasaiC9dYIUCH-CkOLwUHVUekdM7gteQdMUrn7HUiLt1xNSVsvF2Qb3L3SIhO0g_Vg9uywT5Cw=w293-h220



As Mark said, his EVO Wing performs really well at 17.5K, while Mike and I, with our Sport Wings, do better down lower. Mark's photo above is what sent me out to test similar cruise power performance (but at 13.5K in this case), and I was really pleased to get close to his results. The differences in our manifold pressure and fuel flow is very consistent with our difference in altitude. I know my speed would have dropped off up at 17.5K, as I've tested it, and I watched Mark pull away at 15.5K during AVC 2010 (I caught him in the descent tho! :D)

An earlier poster suggested use of the NTPS spreadsheet, and I agree. A 4-way test takes out the one-off performances, and ensures all legs are flown consistently (though the application of its standard deviation calculation). Below is a 4-way test I did in September 2013, just before the Reno Air Races.

kpCB3BH-4yVOos9UXGzsbFNxyvFdQ6SX98_T0mUiChvFzoTmv_eb4NvnCQT7vNsIhu07iF4bPGXfgZFZqg=w400-h120


The result was 224.0 KTAS, and it turned out to be a good run, with a 0.0 StdDev. Those are rare, but anything below 2.0 is considered good, valid data. 224.0 knots is 257.7 mph, and a week later, I qualified at Reno at 254.7, then in 2014 qualified at 257.3. I was happy with that correlation.

And Mike, that is as close as I could find in my data to the conditions you were running in your photo, from what I can tell. You have a fast machine amigo, and should be up at Reno. By the way, what was your RPM and FF in that run (just can't see it).

Another thing I know Dan H and other sharp-eyed readers will see is that I also recorded my EFIS TAS, which averaged 4.2 knots faster than the calculated result. I know that I have Ram Rise and my TAS readout is a tad high at higher speeds (yep, believe it or not, and I've tested for it too, by adjusting IAS from 70 to 170 in level flight, and watching the 5 degree F change in OAT).

So I reckon now, since I live less than 10 miles from Mark, we need to do some more side by side tests, and see what kind of TAS we can get for Jon (and for Mike to chase! :D).

Last note, Todd's 276 mph run at Reno in 2019 was 0.9 mph faster than Bill Beaton's 281 mph qual in his Harmon Rocket a couple year's prior, when the course changes were adjusted out. The speeds at Reno are a completely derived speed, based on time over the set course distance. I'm not saying that to take anything away from Todd or Bill, not at all. As was said earlier, you have to be a bit faster than the final speed on some parts of the course (the Valley of Speed), as the pylon elevation for all pylons is not the same. How one flies the course, manages altitude, g and radius of turn is critical. Todd and Bill set the bar, and I think have a legit claim to being the fastest RV and Rocket in the world. From an RV purist perspective, I guess you could say Bill cheated with a supercharged six, with some nitrous, and Todd cheated with a 100 HP shot of nitrous (plus additional fuel). But its racing, and if you aint cheatin'...well, you know... ;)

It also puts a target on their backs...just sayin! :D

Cheers,
Bob




Checking the pic I uploaded. I swear I have seen 1KTAS faster, but danged if I can find that one. Headed home from Reno this trip...

Well, I just today took a shot at it and was able to match your speed of 214 KTAS, but down low it was more than DOUBLE your fuel flow. It's still a very dirty airplane though - there is quite a bit more speed in it.
 
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Interesting ... I hadn’t considered this. :D

Any idea what switching the alt off is worth?

@30 amps 14.7 volts 45% conversion efficiency, 1.4 HP - you will have to look at your speed-power curve for desired conditions to determine how much that will be in speed.
 
Nasty -

In the EFIS shot at 214, my RPM was 2670 (knob full forward), and 23 GPH (leaned to best power).

Propellers make a big difference. I have the Hartzel BA 2 blade because research indicates its the fastest out there. Side by side comparisons do support that, but there is a significant caveat. The BA pulls very hard at 26-2700 RPM and handily outperforms the MT 3 blade, but at 2300 RPM where I spend 90% of my hours, the MT crushes the Hartzel. I like the outright speed, but had I been able to confirm the significant difference in performance before purchase, I would have gone with the MT.
 
It has been a while since I pushed my EVO rocket down low, but at the 2010 rocket race I was 12 knots faster then the next closest standard wing rocket and that was Greg Nelson’s beautiful sport wing.
My speed in that race was 238.6 knots.
Over six years of racing I made a lot of changes to the airframe in terms of cleaning up the surfaces, but was never able to document any particular mod itself. Little things do add up to substantial gains. One item alone added 6 knots and that was the change from a three blade MT to a two blade Hartzell
I miss the SARL races but my top speeds were pushing Vne and I know I did not have the ability to pull back the power stick in a race.
I continue to fly my EVO and flight plan down low at 205 knots and above 8000 feet 215Knots at 11gph.
I was racing with 10 to one pistons but ECI rings eventually trashed my cam and I had to get an overhaul done. It now runs with stock Lycoming pistons at the above numbers. I have set a personal Vne of 230knots.
 
Small world Tom, but I fly with Coach a bunch and it's his F1 that I bounce my numbers off. I can out climb him, and "almost" hang with him at max RPM, but he walks away at 2300. At 2300, he has to pull more than 2 inches of MP out to let me keep up. That's big.
 
Mike,

Mark and I switched to the Hartzell 80" BA at the same time. Mark from the MT 3-blade, me from an 80" D-twist Hartzell. Mark gained 10-12 mph, I gained 4-5. Up to that point, we were trading races. Since that time, he uses his rear-view mirror more than I do! :mad: :p

Tom, you were always an inspiration, and I still remember the phrase, "Bob, nothing is stock on this Rocket" as the answer to many of my questions about your plane, during my first few SARL races. Likewise with your comment, "you will never look at your plane the same again, once you race". Boy were you right! I miss chasing you!! :D

Cheers,
Bob
 
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