[MarvinL]

On Tim's website the best speed numbers are 163(with possible correction for instrument error to 169) at MAPs of 21.5 to 24.2 and RPMs of 2360 to 2490. The 169 converts to 194 mph. Does anyone know what MAP & RPM Van used to get 201 at 75% power? How does one determine 75% in the LYC IO 540?

 

[Bob Axsom]

No I don't but...

There was an RV-10 in this year's Airventure Cup Race that was painted just like any other RV-10. It was the only tri gear RV that beat me in the race. My RV-6A averaged 193.42 mph for the 407 nautical mile race with the first ~280 miles into a headwind. This RV-10 averaged 203.31 mph. It is registered as N533JD and it is owned by Debbie Dewey. Maybe Van's should question her MAP and RPM.

Bob Axsom

 

[FlyerJumper]

... This RV-10 averaged 203.31 mph. It is registered as N533JD and it is owned by Debbie Dewey. Maybe Van's should question her MAP and RPM.

This was with a 3-blade Aero Composites prop also!

 

[Jeffreymd]

tas

just a little fyi. i'm now flying my new rv10 and i have yet to hit the 200 mph range, and i have a 280 hp io-540. i'm still breaking it in at 75% power, so i'm running 24 square and my average tas is only 180 MPH or 156 kts. go figure.........

 

[rv6ejguy]

There was an RV-10 in this year's Airventure Cup Race that was painted just like any other RV-10. It was the only tri gear RV that beat me in the race. My RV-6A averaged 193.42 mph for the 407 nautical mile race with the first ~280 miles into a headwind. This RV-10 averaged 203.31 mph. It is registered as N533JD and it is owned by Debbie Dewey. Maybe Van's should question her MAP and RPM.

Bob Axsom

What altitude was she running at? Big difference in WOT power and speed at 1000 feet MSL and 8000 feet.

 

[Jeffreymd]

2-3000 ft. i was told to keep it under 3000 till the motor is broken in. i'll keep the 8k ft. in mind. thank you and blue skies, jeff

 

[Bob Axsom]

She had to be low with the head wind

What altitude was she running at? Big difference in WOT power and speed at 1000 feet MSL and 8000 feet.

Everyone I know was flying at approx. 1,000 ft AGL to get out of the headwind as much as possible. Approx 1,800ft MSL is a good guess.

Bob Axsom

 

[rv6ejguy]

Everyone I know was flying at approx. 1,000 ft AGL to get out of the headwind as much as possible. Approx 1,800ft MSL is a good guess.

Bob Axsom

Guess her engine was well broken in, making good power and that 3 blade prop can't be any worse than the Hartzell 2 blade. Impressive speed if that was into a headwind! I hope mine does that well down low. (hello engine room, I need some more manifold pressure here
)

 

[vic syracuse]

I've posted my numbers before, but here they are again: After 350 hours I flight plan 165 KTAS, and generally see 165-167 all the time. I usually fly at 7K-12K feet, WOT, and 2360-2370 RPM's with the MT 3 blade constant speed prop, and burn between 13-14.5 gph. Down low at 3000 feet the speeds do seem lower, around the 158 knots someone else mentioned, with MAP around 24" and RPM 2360, fuel at 15 gph.
Vic

 

[TimO]

My Numbers

While I'm glad people pay attention to the performance specs enough
to note that I did have a definite airspeed error with my old static
ports, the thing that's really important in using my numbers as a yardstick
is to know HOW I fly.

Vic posted his numbers, which seem very reasonable. I just got done
flying from wisconsin to Albuquerque to Vegas. 500 more miles to
LOE now. I cruised the whole way here at a hair +/- 160kts.
Down lower (8500' or so), that was running a MAX of 10gph. Today
at 12.5K, we were running about 8.6gph. At 12.5K I was WOT, but
8500' I wasn't always even at WOT, depending on the turbulence.
(Whenever we were about ready to be beaten up, I prepared by
backing off the power). When I'm running LOP, I pull it back so
my hottest cylinder is somewhere around 25 degrees LOP. Some
of the other cylinders are much more LOP than the hottest. There
is a DEFINITE power increase when I richen the mixture, and I can
get a bit more speed out of it. I would much rather fly this
way than fly ROP, as Vic does (nothing against the way you fly, Vic)
because it costs so darn much less and the temps are so nice.

When I flew to Oregon and back, I figured I saved at least $200 in
fuel over my planned usage, by running LOP. So far on this trip
I've saved a ton too. My temps have been nice and low in cruise
too. On the cooler initial leg out of wisconsin, my CHT's were
310-ish on the low end, and 350-ish on the high end (#1 and 2).
EGT's usually in the high 1300's.

So there is one thing that I've simply NEVER done, and that's to
take the plane and try for the best speed for cross-country
flying. I could give a rats keister if it takes me an extra 25 minutes
to get across the country.....but if I can do it for a hundred
bucks less....man that's livin'!

I fully expect that the determined -10 builder with the ego that
needs to post fast numbers should easily be able to do so. Look
how well Debbie Dewey did in the race. I didn't even realize there
was another RV-10 heavier than mine but it turns out she is 25lbs
heavier. Mine's a stock IO-540, 260HP, no-skinny-minnie plane,
with a 2-Blade hartzell. Some people stuff in 300+ HP engines,
or trim the weight and keep it light. Most anyone should be able
to beat my speeds....even me, if I flew it in a way that didn't
save so much fuel. LOP though....that's where it's at for me.
My earlier posted numbers on my site should probably be ignored.
I'd remove them, but it's still a reference point. With nearing
160 hours on the plane now, I've learned a lot, and found
a style I like. Finding out my airspeed was way off was another
nice bonus, and fixing it was great too.

I'll try to remember to log some numbers at a couple of altitudes
yet this week.

Oh, and to chime in on the other Oil temp thread, on my first
leg, my oil temp was 164-ish. If anything, that's cooler than
I'd want. No problems with oil temps at all in my case.

Tim

 

[dan]

When I'm running LOP, I pull it back so
my hottest cylinder is somewhere around 25 degrees LOP. Some
of the other cylinders are much more LOP than the hottest.

Tim,
Good stuff. My 2 cents -- get those injectors balanced as close as you can. It'll end up translating to slightly better economy (higher mph per gph = mpg), because you won't have to run so lean to ensure all 6 are LOP.

 

[vic syracuse]

MT vs. Hartzell Blended airfoil prop

Tim and I were both at LOE this past week end, and we took the time to do a fly off, since I have the MT 3 blade and Tim has the Hartzell blended airfoil. Tim will be posting the results on his web site. Suffice it to say that I have been vindicated. We were straight and level, with matched rpm's, fuel flow's and MP (which we checked on the ground), and we have the same instrumentation systems. At WOT and 2400 rpm I was pulling away by about a knot or so. Tim then increased rpm's to 2460, and started to catch up. I matched RPM's and pulled away again. Not very scientific, but I think we've put to rest that the 3 blade MT is way slower. I heard one other RV-10 saying "hey, you guys are pulling away and I can't keep up" but I'll let them 'fess up to who they were. It was all in fun, and a good time was had by all.

Vic

 

[chuck]

Tim and I were both at LOE this past week end, and we took the time to do a fly off, since I have the MT 3 blade and Tim has the Hartzell blended airfoil. Tim will be posting the results on his web site. Suffice it to say that I have been vindicated. We were straight and level, with matched rpm's, fuel flow's and MP (which we checked on the ground), and we have the same instrumentation systems. At WOT and 2400 rpm I was pulling away by about a knot or so. Tim then increased rpm's to 2460, and started to catch up. I matched RPM's and pulled away again. Not very scientific, but I think we've put to rest that the 3 blade MT is way slower. I heard one other RV-10 saying "hey, you guys are pulling away and I can't keep up" but I'll let them 'fess up to who they were. It was all in fun, and a good time was had by all.

Vic

I will agree with your statement "not very scientific" and disagree with the rest. Since scientific tests done by Van has shown the Hartzell to be several mph faster, I think you have shown that your 10 is rigged better or your engine is more efficient (EI, exhaust etc).

 

[rv6ejguy]

Tim and I were both at LOE this past week end, and we took the time to do a fly off, since I have the MT 3 blade and Tim has the Hartzell blended airfoil. Tim will be posting the results on his web site. Suffice it to say that I have been vindicated. We were straight and level, with matched rpm's, fuel flow's and MP (which we checked on the ground), and we have the same instrumentation systems. At WOT and 2400 rpm I was pulling away by about a knot or so. Tim then increased rpm's to 2460, and started to catch up. I matched RPM's and pulled away again. Not very scientific, but I think we've put to rest that the 3 blade MT is way slower. I heard one other RV-10 saying "hey, you guys are pulling away and I can't keep up" but I'll let them 'fess up to who they were. It was all in fun, and a good time was had by all.

Vic

Thanks Vic. I have an MT and hated to hear all the time how much faster the Hartzell was. The MT can't be half bad. Side by side comparisons ARE fun!

 

[johngoodman]

Vic,
I read Tim's post; and I think he was real honest in his opinions. Obviously, there are advantages & disadvantages to two vs three blade props. I do love the idea that you both have Cheltons. That does it for me - Cheltons! I've got to admit that the MT is what I'm leaning toward. By the way, I still need you to come influence me in PTC sometime (g)....
John Goodman

Tim and I were both at LOE this past week end, and we took the time to do a fly off, since I have the MT 3 blade and Tim has the Hartzell blended airfoil. Tim will be posting the results on his web site. Suffice it to say that I have been vindicated. We were straight and level, with matched rpm's, fuel flow's and MP (which we checked on the ground), and we have the same instrumentation systems. At WOT and 2400 rpm I was pulling away by about a knot or so. Tim then increased rpm's to 2460, and started to catch up. I matched RPM's and pulled away again. Not very scientific, but I think we've put to rest that the 3 blade MT is way slower. I heard one other RV-10 saying "hey, you guys are pulling away and I can't keep up" but I'll let them 'fess up to who they were. It was all in fun, and a good time was had by all.

Vic

 

[gmcjetpilot]

Its all trade offs

Thanks Vic. I have an MT and hated to hear all the time how much faster the Hartzell was. The MT can't be half bad. Side by side comparisons ARE fun!

Its not a matter of "Bad-ness" its just three blades is less efficient than 2 and thicker blades (composite/wood) is not as efficient as metal. The MT has many other advantages but at a cost premium but no bad-ness. No one said MT's are bad. However if you average all the "side by side fly offs" you will find a trend of abut 4 to 8 mph or spilt the diff, call it 6 mph. This is not surprising or unexpected. In trade off, for a price premium, people love the looks, lower weight and smoothness. Its never ever about bad-ness its about trade offs.

I will say that the Aero Composite is a totally different prop than a MT. The Aero Composite is a very construction, made stiff and higher strength composites. In trade you get a thinner airfoil but its not as smooth as the wood core MT's. The Hartzell of course has the "Best Value" title in my opinion, but that does not make it best for all who put premium in other characteristics. However if absolute speed is key to you a two blade Hartzell is best and has been shown over and over and over again and again. THAT IS OK. Its all trade offs. You can't have everything.

Here's Van's take on it (click me ans watch it grow):

 

[az_gila]

Which is better....

Its not a matter of "Bad-ness" its just three blades is less efficient than 2 and thicker blades (composite/wood) is not as efficient as metal. The MT has many other advantages but at a cost premium but no bad-ness. No one said MT's are bad. However if you average all the "side by side fly offs" you will find a trend of abut 4 to 8 mph or spilt the diff, call it 6 mph. This is not surprising or unexpected. In trade off, for a price premium, people love the looks, lower weight and smoothness. Its never ever about bad-ness its about trade offs.

I will say that the Aero Composite is a totally different prop than a MT. The Aero Composite is a very construction, made stiff and higher strength composites. In trade you get a thinner airfoil but its not as smooth as the wood core MT's. The Hartzell of course has the "Best Value" title in my opinion, but that does not make it best for all who put premium in other characteristics. However if absolute speed is key to you a two blade Hartzell is best and has been shown over and over and over again and again. THAT IS OK. Its all trade offs. You can't have everything.

Here's Van's take on it (click me ans watch it grow):

I don't know.. it sounds to me that a side by side fly-off at LOE with both pilots measuring MAP, fuel flow and rpm with identical equipment (the instruments, that is) is actually more scientific that Van's gross estimate of engine output that is in the PDF attached....

I vote for the LOE fly-off being more representative....

gil in Tucson

PS LOE 06 was fun... say thanks to the beer makers..... I liked the IPA

 

[Ironflight]

Smooth.....

I wasn't in either airplane for the fly-off, so can't comment at all about the speed issue, but I can tell you that Vic's prop/engine combination was the smoothest I have felt in any piston engine airplane I've ever been in (and that's a third of a century of flying...)!

Vic started it up, and my first thought was "boy, that starter is smooth, and it sure turns the prop fast!" Then I realized that the engine was running - the engine didn't seem to run....it just seemed to hum! Incredible combination (but I still like my BA Hartzell on the Valkyrie....).

Paul

 

[chuck]

I will agree with your statement "not very scientific" and disagree with the rest. Since scientific tests done by Van has shown the Hartzell to be several mph faster, I think you have shown that your 10 is rigged better or your engine is more efficient (EI, exhaust etc).

After reading Geroge's post refeshed my memory, I think the Van's test is not very scientific either. Both sets of tests have not controlled for the airframe and engine enough to draw a conclusion. I guess for now the jury is out for me, though theory says the 3 blade should not have a chance

Randy Lervold did tests with 4 different props on an RV8 (no BA or MT). His method is what I would trust though there are many issues with speed measurements better than 1%.

http://www.romeolima.com/RV8/Prop.htm

 

[dav1111]

MT and Hartzell Props

At LOE2006 I had the opportunity to fly some loose formation with Tim Olson (260HP Hartzell) and Vic Syracuse (310HP MT). At one point the three of us set MP and RPM and it was obvious to me that both Vic and Tim were pulling away from me (260HP MT). My best guess was that they had about 4-5 mph better speed than my RV-10 at about 5000 MSL.

Am I disappointed? Not on your life, I love my 3 blade MT Prop and didn't have to pay a premium as I was on the first factory group buy of 10 which brought the price down close to Van's Harzell price.

What I would really like to see is how the new Harzell composite 3 blade prop performs. Not that I am going to change just to pick up a little more top end airspeed.

I haven't finished installing my OX system (all plumbed but still working on interior of airplane). I hope that when I get the OX in and start flying at 15000 to 17000 feet that I will really pick up some extra performance with the MT, which climbs great.

 

[Mike S]

A better test???

Seems to me that one of the simpelest ways to settle this MT vs Hartzel thing is to take the same two planes as in the post by Vic (#12) and repete the fly off, after switching props from plane to plane, re adjusting CG and weight to reflect first flight.

This would cancel out variances in engine/airframe, leaving the prop as the only major variable.

Will this happen-------------doubt it.

But it would be fun.

Vic and all--------thanks for the reports.

Mike

 

[rv6ejguy]

Van's qualifies their many assumptions on engine output. Bottom line- they don't know the relative power outputs since neither engine was dynoed. So, bottom line- not scientific at all and as Vic pointed out, neither was their test, he simply posted it for interest sake.

The scientific method involves changing only one variable and observing the results.

As one pointed out here, the best way to do this is to switch props between airframes and do a side by side. Then and only then will this question be resolved. Vic has a fast -10 it sounds like.

1% differences in solo testing are nearly impossible to quantify and essentially meaningless anyway.

MTs tested on other airframes have shown to be more efficient (not against Hartzells) at lower rpms, between 2300 and 2450 and indeed MT told me that my prop was about 3% more efficient at 2550 than at 2700 so I ordered a different control box (electric) and altered the redrive ratio to increase prop torque.

The root of the MT is fairly thick but this part does not produce any useful thrust, the outer 2/3rds, produces the most. My MT has about a 9% section at 2/3rd span. Not sure what the Hartzell is but assumptions about thinner sections are just that. Catto's 3 blade fixed pitch props seem to be very competitive with any of the metal 2 blade ones for speed. There are too many variables to look at one design on paper and say it is better or worse. You need to fly them under controlled conditions and see.

 

[rvbuilder2002]

Picking Nits????

I don't see where the article states any info as certain or proven. Multipal times it says "how much more, we don't know".

I think the main point is that unless raising compression ratios, balancing, porting, and flow matching a Lycoming engine is a total waste of money and provides no HP increase what so ever, the Hartzel must be faster than the MT. True, no one knows what the HP difference is between the two airplanes, but it can be expected that Vics would be faster with all the extra money he likely paid for all of this other engine work. I believe the quoted 310 HP was info provided by Vic (likely a guess provided by the engine builder)

The way I see it... the Hartzel is faster or everyone that pays for extra engine upgrades is flushing there money away.
I know that there are other benefits smoothness, etc but this discussion was comparing the two props for speed.

I do agree that it would be nice to know how much faster.

 

[vic syracuse]

I feel I need to put something else to rest here, because I have heard a number of comments about all of th emoney I paid for my engine. See, in my RV-6 I bought a new Lycoming from Van. The first week I received it I also got an AD in the mail for the Cylinders. The engine was never very smooth, typical of the 4 cylinder lycomings, I know. So, when it came time to procur an engine for the RV-10, I looked at alternative routes before just buying the new engine. Performance Engines built my engine up the way I wanted it, with all of the B&C accessories I always end up adding anyway to the new Lycoming, including the SD-8 standby alternator and lightspeed ignition on one side and magento on the other, airwolf remote oil filter setup, airflow performance injection, and they broke it in on the dyno/test cell for $35K, including shipping. The new Lycoming from Van's was pushing $41K without shipping, and without all of the balancing, B&C accessories, etc. To me it was a no brainer. I am not about spending alot of extra money. Neither is my wife. As for the 310 HP, that is at 2800 RPM. Most any lycoming will do that at that RPM. I DO NOT run it that high. I limit it to 2700 rpm as that is the limitation of the MT prop, and I see fuel flows at takeoff which match the lycoming manual for about 260 hp.---- 23-24 gph at WOT and 2700 rpm. I've mentioned before how smooth the engine is, and Paul Dye reported taht on an earlier post in this thread as well. MOre than anything, smoothness and reliability is what I wanted for a 4 place cruiser, and I think I achieved that WITHOUT spending ANY extra money.

Vic

 

[rvbuilder2002]

I'm looking at it differently...

Performance Engines built my engine up the way I wanted it, with all of the B&C accessories I always end up adding anyway to the new Lycoming, including the SD-8 standby alternator and lightspeed ignition on one side and magento on the other, airwolf remote oil filter setup, airflow performance injection, and they broke it in on the dyno/test cell for $35K, including shipping. The new Lycoming from Van's was pushing $41K without shipping, and without all of the balancing, B&C accessories, etc. To me it was a no brainer. I am not about spending alot of extra money. and I think I achieved that WITHOUT spending ANY extra money.

Vic

I guess we look at economics differently.
It appears that you did spend less than you would have for a factory Lycoming, but I doubt that you got the extra performance upgrades from Performance Engines for free. Which means you could have bought an engine from them for even less money.
My point is that if these upgrades produced no performance benefit then paying for them was a waste of money. If they did produce a benefit, then the test results show that the Hartzel prop, must have better speed performance that the MT.

There is nothing wrong with anyone spending the extra money that they want to, to get benefits that they want, I.E. "the smoothest engine I have ever felt".

This discussion was about speed comparison of the MT to the Hartzel.
I think there is evidence to show that the Hartzel is faster. I also agree that we don't know how much, but that doesn't mean that people can just ignore the evidence (even if it is not highly scientific) just because they are hoping for a different test result.

I strongly disagree that turning any IO540 260HP Lyc to 2800 would net you 310 HP. I doubt it would even be 1/2 that much increase.

 

[glenmthompson]

Repost of my previous language., my apologies

Just the quick and dirty, ...cuz...I have written at length all of this before. In N331JH, we now have 204 TAS MPH @ about 75% (+/- 7000?ft WOT, LBP, 2350 RPM) Originally could not get above 185 MPH....Fastest I can get is @ 3500 ft, WOT, 2550 RPM LBP, and I get 228 MPH TAS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Now boys and girls, again, this is with a 35 lb lighter than prototype, average fit and finish RV-10 with a Schmidt Aviation built up O-540 (carb).!!!!!!
.
Now the best of all, listen carefully!!!! The engine was purchased rebuilt, from Schmidt Av. for $19,000 with ovhld chrome cyl! Jim has the blended 2 blade Hartzell.....Engine was complete ready to install and had 2 hrs run time when delivered. Paint was exceptional, timing was perfect on the mags. Looked like it was assembled by an anal builder like myself.
Now for IMHO. ..Why in the world spend 40k +++ for an engine like previously mentioned, when you can get better than Vans numbers, a new cool looking, fast prop, and all other FFW stuff for less than 30K? That gives you literally tens of thousands of dollars extra to put in that cool panel so you can keep up with that fast, new airplane! Imagine if you will, a fully EFIS, fast RV-10, and from panel fwd, having less than 50K! It can easilly be done! That puts the total cost of your new 10, if you paint it yourself, WELL UNDER $100K!!!!!!
BTW, Jim has given me permission to say that anybody that wants to fly N331JH with me and see how it cool it goes, is more than welcome to come to WPB, donate some gas money and lets go have a $500 hamburger! I also guys, still have that open challenge to do a side by side flying comparison with any other 10! Or any other RV for that matter for comparison sake/proof of my numbers.... Lets hear it!!!! Keep up the excitement, I know I surely am excited about this way cool plane! (even though my legs get warm flying haha)!
Glen

 

[Mike S]

Glen, good to see you back.

Mike

 

[Auburntsts]

Glen,
What did you do to pick up 19 MPH (204 vs 185 TAS)?

Todd

 

[rv6ejguy]

MPH....Fastest I can get is @ 3500 ft, WOT, 2550 RPM LBP, and I get 228 MPH TAS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Now boys and girls, again, this is with a 35 lb lighter than prototype, average fit and finish RV-10 with a Schmidt Aviation built up O-540 (carb).!!!!!!
.

Holy cow! 228mph with a carb. Maybe my Sube wasn't such a great idea.

 

[SteinAir]

Something doesn't make sense here Vic...no flames intended, but the fact that you state you're getting 50 extra hp out of only 100 RMP is more than highly unlikely. Something just doesn't jive........the RPM, FF, MP number are a start point, but certainly not the only measurement of hp.

Your math is giving you a 20% bump in hp with a 4% increase in RPM....Does your fuel flow increase proportionally; i.e. from 24 gph to 31 gph with only a 100RPM increase? If so, then something is really wrong with this picture. How much MP increase does it take to get that last 100RPM?

I'm still scratching my head because overall one of a few things has to be true.... either your original HP is off and your engine didn't make 310hp at 2800rpm, or your prop is just 'plane' slower. You simply can't have 50 extra hp, be only 1-2 mph "faster" then claim the prop is equally efficient as the 2 blade. It just doesn't jive. Either you're losing your extra HP to prop efficiency loss, or your prop is equally efficient and your engine isn't nearly as powerful as you thought. Personally, I suspect the prop not the engine because the guys at Performance know what they're doing! I'm afraid it's one or the other, but not both...but then again what do I know - I'm just a dumb old engineer who doesn't even have his own RV 10 to compare with so take it all for what it's worth...just some rambling monologue.

Anyway, not that it really matters because you're plane is darned nice and darned fast.....but those numbers just don't jive (260 hp @2700 vs 310 @2800).

So...about performance engines, I too am having some engine work done for a 360 I'm building up by performance engines. They are a little hidden jewel that is traditionally used by the high end racing/airshow crowd. For example, I'm having a cam re-profiled and re-ground by them to sweeten up the engine a little bit, and a few other extra whizbang do-dads (like porting, polishing & a 5 angle valve job) to make my new engine purr. Surprisingly, they aren't any more expensive than the other 2 well known "super lyc" builders.

I say that Vic should just swap his 3 blade MT with a 2 blade Hartzell, go fly and see what happens. My opinion....I'll bet a dollar to a donut he picks up some surprising knots, but that's just my opinion not based on anything other than personal thoughts.....and jealousy of Vics & Tims & Russ's nice RV10's! Not meant as a slam to those gorgeous looking MT's, but I'm a numbers man....so...

Cheers,
Stein.

I feel I need to put something else to rest here, because I have heard a number of comments about all of th emoney I paid for my engine. See, in my RV-6 I bought a new Lycoming from Van. The first week I received it I also got an AD in the mail for the Cylinders. The engine was never very smooth, typical of the 4 cylinder lycomings, I know. So, when it came time to procur an engine for the RV-10, I looked at alternative routes before just buying the new engine. Performance Engines built my engine up the way I wanted it, with all of the B&C accessories I always end up adding anyway to the new Lycoming, including the SD-8 standby alternator and lightspeed ignition on one side and magento on the other, airwolf remote oil filter setup, airflow performance injection, and they broke it in on the dyno/test cell for $35K, including shipping. The new Lycoming from Van's was pushing $41K without shipping, and without all of the balancing, B&C accessories, etc. To me it was a no brainer. I am not about spending alot of extra money. Neither is my wife. As for the 310 HP, that is at 2800 RPM. Most any lycoming will do that at that RPM. I DO NOT run it that high. I limit it to 2700 rpm as that is the limitation of the MT prop, and I see fuel flows at takeoff which match the lycoming manual for about 260 hp.---- 23-24 gph at WOT and 2700 rpm. I've mentioned before how smooth the engine is, and Paul Dye reported taht on an earlier post in this thread as well. MOre than anything, smoothness and reliability is what I wanted for a 4 place cruiser, and I think I achieved that WITHOUT spending ANY extra money.

Vic

 

[vic syracuse]

Stein, no flame received. I've just tried to post what my numbers are and that I really didn't spend a lot of extra money on my engine. I wanted an engine that was reliable and smooth, and I think I got that. I've owned a number of airplanes over the years, and most everyone who has is very much aware of all of the incipient cracking that goes on. I don't have any of that on this one, at least yet, but at 360 hours, normally there would be some cracking---- baffles, exhaust, etc.
So, here's the comment I've been avoiding, but you're kind of forcing me into it. I don't really believe I have a 310 hp engine. The data plate is stamped that way, so I had no choice but to register it as that. However, I have had no luck getting the dyno sheet from Performance Engines, and I do believe they exaggerate a little (maybe a lot). I can't run it at 2800 rpm due to the limitation on the prop. Do I believe I would get that much HP from another 100 rpm? No. I keep asking for the dyno sheet from PE, but no luck, so we'll leave it to them to prove otherwise. I've asked Stuart Featherstone multiple times for the dyno readout. The fact that I can't get it tells me something is a little exaggerated.
However, all said and done, I think a derated engine will give long term reliability, which is what I was after.
The flight test Tim and I flew was all for fun. It really doesn't prove anything, nor am I out to prove anything here. There's just been so many questions asked by those who are trying to decide on what choices that if all of us just put our numbers out there it will give more data. In no way do I mean for any of my posts to try to convince someone to do soemthing because I did it that way. Unless of course I feel someone is doing something that is unsafe.
In the end, I am a very happy customer, and pleased with the combination of performance that I have from Van, the prop, and the engine. But this is experimental aviation, and what makes the world go around is that others might enjoy a different combination, and even achieve better performance. All of the RV series have continued to see improved performance in all areas over the years because of all of the different combinations tried by others. That's why we are here.
Thanks for your opinion, and forcing me to reply. I had actually decided to not post about it any more because of the nit picking. It was all don ein fun, and unfortunately inflection doesn't come across in email.
I think we can summarize it as thus: Vic is getting a consistent 165-170 KTAS on an RV-10 with an IO-540 engine built by Performance Engines and mated to an MT prop, and perhaps leave it at that. It's very smooth, the actual hp is unknown.
Any one is invited to come to Atlanta and fly my airplane as just one example of how to do it.

Vic

 

[w1curtis]

Not very scientific, but I think we've put to rest that the 3 blade MT is way slower.

Quite the contrary, IMHO, I think you have added fuel to the (controversy) fire.

Vic,

I think part of the problem here is that with each post you give some information but gloss over or left out some relevant information. Not saying that this is intentional but this I think is what makes it seem that, at best; something is being (conveniently) overlooked and at worst; dis-ingenuity. I remember one poster (not you) giving his ground speed on a downwind leg as an indicator of performance. Clearly, your engine is producing more power (9.5:1 vs 8.5:1 compression) than Tim?s but you are only 1 knot faster. I think everyone is in agreement that the MT looks better and is smoother, but you are now trying to convince yourself and other that it is also just as fast as the 2 blade Hartzel.

Here is an example

I heard one other RV-10 saying "hey, you guys are pulling away and I can't keep up" but I'll let them 'fess up to who they were.

The detail that this was Russ Daves in an RV-10 with a standard 260 HP engine and the same 3 blade MT prop as you, was admittedly left out. Same engine configuration as Tim, except Russ has the MT prop.

You have been flying for 360 hours now. If you really want to put this to rest, a recorded result of a couple of grid circuits at various altitudes and power setting would really help in that end. Otherwise we can chalk all this up to Cognitive dissonance.

 

[SteinAir]

......
Thanks for your opinion, and forcing me to reply. I had actually decided to not post about it any more because of the nit picking. It was all don ein fun, and unfortunately inflection doesn't come across in email.
I think we can summarize it as thus: Vic is getting a consistent 165-170 KTAS on an RV-10 with an IO-540 engine built by Performance Engines and mated to an MT prop, and perhaps leave it at that. It's very smooth, the actual hp is unknown.
Any one is invited to come to Atlanta and fly my airplane as just one example of how to do it.

Vic

Fair enough and true enough....in reality it really doesn't matter. All of us with RV's generally have planes that'll poke holes in the sky a lot faster than we normally fly anyway. Me, I'm too poor to fly with the black knob pushed all the way in, so I normally loaf along at some reduced LOP speed to save fuel. People often aske me how fast my plane is and I just say...."as fast as you want to pay for the gas"! I'm building a new engine myself right now, and while I have a goal to make it a little higher hp than stock, I will have no dyno sheet so I'll never really know how much hp is getting to the prop, nor will I really care. I just want a fast/nice plane! I'm surprised at performance and your dyno sheet, but normally they are a top shelf / top notch outfit. Try talking to Ron and see if that helps. Anyway, happy flying and enjoy the plane. You've done this enough times now that you've earned the right not to reply to any of our nitpicking!

Cheers,
Stein.

 

[glenmthompson]

Beat this horse to death earlier....

Glen,
What did you do to pick up 19 MPH (204 vs 185 TAS)?

Todd

Yep the horse is dead, but in summary, IMHO it was......Adding side and bottom gills in cowling for extra cooling(# 5 is always hot).....Painting/fairing/smoothing.....Jim and his tool box riding in the back, read aft CG.....flying in smooth air with AP on, with alt hold ( we lose 4 knots almost instantly in choppy air).....having the elev. faired exactly level with stab (played with shims under stab LE) at 150 MPH IAS.....Ball exactly centered with feet off at 150 MPH IAS.....flaps reflexed up slightly (don't ask how much, I have no idea, I am guessing TE up about 1/4" form Vans rec.).....ailerons matching flaps, not tips......antennas on bottom in "dirty" air.....Trim tabs exactly level with elev. at the above mentioned 150 MPH IAS......Monarch Butterfly decals.....Extreme heat radiating from bottom of tunnel area acting as some sort of time warp , heat lifting earth opposing lifting action, thereby lowering induced lift....My burning leg hairs on the tunnel, acting as some weird kind of thermal/smoke thrust vector out of the tail cone.....Oh, and last but absolutely not least, a broken in engine that can be left at WOT long enough so as not to overheat, thereby allowing TAS to slowly creep up ....
.
Does all this make sense intuitively that it would add up to 19 mph? I think not, but hey, whatever works. Right?
Glen

 

[rv6ejguy]

At the end of the day, when one plane pulls ahead of the other in a side by side, it is faster. If the fuel burn is about the same, well you have better package.

I've seen two instances now where carbed RV6s (O-360s) have gone by IO360 powered RV8s. Hmmm. Shouldn't be with the same Hartzell C/S props and in one case the RV6 had two people on board and the -8 only one. Obviously there is a big variation in power between engines. No dyno numbers available (on the same dyno), no direct comparison as to the cause.

 

[aadamson]

Well Maybe this will help

I think the only way to really determine this is to level the playing field. I've been following "Baffling" Bob's discussions and found that his "handicap" method might be worth doing for those really interested in some speed comparisons.

I've retyped the document that I found on the air-race website and created it in PDF. I just noticed it still has a few typo's, but what the heck, it's readable, accessable, and maybe worthy a look.

Take similar airplanes, follow the math, and work up your handicap and report back.

Just a thot anyway.

Here's the document if interested.

http://bellsouthpwp2.net/n/e/ne1h/Air Race Handicap.pdf

 

[RV10Man]

airspeeds

I'm not sure I really understand all the hype about IAS, TAS, etc.....
I've NEVER been accussed of being very smart. But, educate me here, please. What I feel I'm most interested in, is how fast I can cover a mile, in MPH. As I've never been able to see a knot on the ground, Every place I've flown (about 800 hrs. worth) all I've been able to lay out on the ground has been in mile sections. Isn't that what we're taught in ground school & pilot training, use section lines for reference points?
Again, Isn't what we're really concerned with is how fast we can get from point A to point B? I realize fuel consumption does play an important role, but that goes back to the rule of "how fast can you afford to go?"

Marshall Alexander
RV10 Wings almost done
O540 rebuilt myself, less than $15K

 

[RV10Man]

PS

I realize the "V" speeds are based on airspeed.

Marshall Alexander

 

[Kevin Horton]

I think the only way to really determine this is to level the playing field. I've been following "Baffling" Bob's discussions and found that his "handicap" method might be worth doing for those really interested in some speed comparisons.

I've retyped the document that I found on the air-race website and created it in PDF. I just noticed it still has a few typo's, but what the heck, it's readable, accessable, and maybe worthy a look.

Take similar airplanes, follow the math, and work up your handicap and report back.http://bellsouthpwp2.net/n/e/ne1h/Air Race Handicap.pdf

Unfortunately, the method in this document will give results that vary with wind speed. Racers who want to get the lowest handicap should choose a day with zero wind at altitude. RV builders who want to impress us with a high claimed TAS should do the testing on a day with high winds at altitude.

 

[aadamson]

Unfortunately, the method in this document will give results that vary with wind speed. Racers who want to get the lowest handicap should choose a day with zero wind at altitude. RV builders who want to impress us with a high claimed TAS should do the testing on a day with high winds at altitude.

Kevin, maybe I'm just not thinking straight (wouldn't be the first time), but doesn't the 3 legs of the triangle factor out the wind? Maybe the formula needs to be changed to use the triangle calculator on various websites to provide TAS. You could average your 5 numbers, then plug each average into the calculator to give you your corrected speed, then use that. That would negate the wind effect I believe.

Course as I said, maybe I'm just not thinking straight.

 

[Kevin Horton]

Kevin, maybe I'm just not thinking straight (wouldn't be the first time), but doesn't the 3 legs of the triangle factor out the wind? Maybe the formula needs to be changed to use the triangle calculator on various websites to provide TAS. You could average your 5 numbers, then plug each average into the calculator to give you your corrected speed, then use that. That would negate the wind effect I believe.

You can do runs in as many different directions as you like - if you average the results it will not equal the TAS. For example, using the 3 runs 120 deg apart method touted earlier:

Let's assume the TAS is 180 kt, with a 30 kt wind from 270. The runs are done with headings of 360, 120 and 240. If do the calculations, you'll find the ground speeds for each run are:

360 deg: 182.5 kt
120 deg: 206.5 kt
240 deg: 154.7 kt
average = 181.2

This isn't far off the 180 TAS, but the error goes up substantially as the wind speed increases. If the wind speed is 50 kt (not unheard of - I've see more than 50 kt at 6000 ft many times), the average ground speed is now 183.5 kt.

 

[cstanley]

Radiation Heat Issues

A few months ago, I read a thread which I can only characterize as a "rant" about excessive heat under the belly and in the tunnel. I'm wondering whether those of you with completed -10's and apprciable hours are seeing this issue repeated, or if it was an isolated incident. I've been planning for how to deal with it, but don't want to add the weight/time/effort/cost to do so if it is not a typical condition in the design.

 

[n2faith2]

Tunnel Heat

While building my 10 I became concerned about tunnel heat because of all the posts. I considered all the options presented (even those in left field) and decided I'd wait and see if I actually experienced the problem before trying to "fix"it. I'm glad I waited. My tunnel is actually cool to the touch. Front and rear. I attribute that to two things.........RPV around the heat box and Vetterman exhaust. My addl 2 cents..........My MT prop is as smooth as silk and my Barrett Precision Engine purrs. My numbers are the same as Vics'.

Bill Stegemann
N545RV

 

[Jim & Julie Wade]

Heat

My 2 cents worth!! In intalled heat valves no sealer. Used 5/8 foam insulation from Aircraft Spruce in all the floor and walls of the tunnel. NO HEAT PROBLEMS!!!!!!! Have Vetterman exhaust. Used the heat once this week, works GOOD!!! Have also flown in 90 degree weather no heat problems.
Jim
40383
N369JW

 

[glenmthompson]

HHMMM

A few months ago, I read a thread which I can only characterize as a "rant" about excessive heat under the belly and in the tunnel. I'm wondering whether those of you with completed -10's and apprciable hours are seeing this issue repeated, or if it was an isolated incident. I've been planning for how to deal with it, but don't want to add the weight/time/effort/cost to do so if it is not a typical condition in the design.

Hey Stanley...Come on by FD38 sometime, fly our 10, look at the build, feel the still very warm tunnel after several fixes, see the scars on my leg and see if you can still call my thread a rant. I guess Vans was also ranting when they came out with one of their rare SB?s addressing this very problem...... I also thought this thread was about TAS in the 10...??? And once again, our numbers are BETTER than Vans....Oops, I fell off my soap box.
Glen

 

[ScottSchmidt]

TAS Numbers

This weekend my wife and I went to Tucson AZ for a fun trip and this was also the first flight that I had my all my wheel pants and fairings on. I put them on the night before the trip and took the plane out for a quick flight and I could not believe the difference in airspeed. At 24.5 inches and 2500 RPM my TAS was 181 knots. They definately add around 10 - 15 knots.

Here are some numbers from the trip.

I was cruising at 10,500 ft., 19.4 inches, 2340 RPM, 13.4 GPH, (around 60 deg. rich of peak) and I was seeing TAS of 165 to 167.

Coming home from Tucson on Sunday I had a nice tailwind and saw ground speeds around 190 knots the whole way. I can't tell you how much fun we were having cruising at 218 mph.

 

[dan]

Question about crosswind calculations/indication... In one of those photos it shows winds as 057 at 3, but a xwind component of 4? Am I not interpreting that correctly? Rounding error?

 

[Kevin Horton]

Question about crosswind calculations/indication... In one of those photos it shows winds as 057 at 3, but a xwind component of 4? Am I not interpreting that correctly? Rounding error?

I'm betting that the two items are calculated at different times, and the sensed conditions changed ever so slightly between the times the wind and cross wind were determined.

This is very much a case of "measure with a micrometer and cut with an axe". The precision of the wind calculations is very dependent on the heading and airspeed accuracy. There is probably enough error in both of those to make the wind values plus or minus several knots.

 

[ScottSchmidt]

Error

I might have bumped the rudder a little, or the wind may have changed a little but it seems like the X-Wind component should never be more than the absolute no matter what type of calcuations are going on unless they are different algorithms that are being processed at the same time and one is not a function of the other.

All I really know is I had some great tunes playing, my performance numbers were exactly what Van's promised, and the scenery was to die for.

Big Cottonwood Canyon

Lake Powell

Grand Canyon

Sedona

Monument Valley

 

[Randy DeBauw]

When I flew with Ken Kruger to do a speed run we flew my plane at 8000 adj. alt., full throttle, 2500 rpm. We flew a box pattern and use the ground speed of the gps to get the speeds. He used those numbers to come up with top speed. At 8000 ft. full throttle is very close to 75% power. As it turned out my speed was low because my ailerons were not set correctly and was adding extra drag. I have not rerun the box since the ailerons have been set correctly. By the way flying at 8000 ft. adj and full throttle we were burning 19.2 gph. Randy DeBauw 40006.