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N45678 Cruise testing

Wesael

Well Known Member
I have been working and refining little details of the School Bus.

Worked on the fuel system a little last week and seem to have it dialed in a little better now.

IMAG0683.jpg


This was after about 60 miles of level flight with the a/p flying and everything stablized.

Fuel flow is 11.8 running 179kn TAS at this altitude LOP. I am still testing and contemplating tuning #5 cyl as you can see it is quite a bit leaner than the rest of them and is always the first to peak.

It appears to make about the same speed on approx .4-.5 GPH less with each 1000ft of increase in DA but I have not yet made a chart to reflect that. I might do it in the future.

Sorry about the picture being choped off at the top. It is running 23.4in MP.
 
Thanks for sharing this. As a fellow Skyview owner, its neat to compare how other people have chosen to configure the layout of the screen. Looks like you're getting some great numbers.

I notice your indicator near the MP gauge says PK (peak), yet obviously you are a little LOP. I have found that mine dont always exactly correlate right on spot too. At least I know I'm not alone now.

I'm trying to learn more about LOP operation and I know this is a primer war type subject but never the less, here we go! Best that I have recently come to understand it, with 70% power you would want to run more LOP than -04F. Should be closer to 25. What are your thoughts on this matter? See 'red box' concept below. Just curious because in mine I have a hard time hitting 25 on all cylinders before it loses drastic amounts of power and/or runs rough. I'm sure I could benefit from some tuning. I'm still learning about all this and so lets keep this educational!

Red Box = No Fly Zone

At and below about 60% power, there is no red box. Put the mixture wherever you want it.
At about 65% power or so, 100ºF ROP to Peak.
At about 70%, 125ºF ROP to 25ºF LOP.
At about 75%, 180ºF ROP to 40ºF LOP.
At about 80%, 200ºF ROP to 60ºF LOP.
 
I'm with both of you guys on this and until I went up to Airflow Performance and had Don Rivera fly with me and record EGT's and fuel flows, I couldn't run LOP successfully either. We then balanced the 6 EGT's with an assortment of different orifices.

My middle two cylinders have a slightly larger fuel injector orifice to better match the other four cylinders and now, running the leanest cylinder LOP at 50 deg LOP gives me six pretty closely matched EGT's...all LOP and around 11.4 GPH.

That said, it costs me around 12 MPH TAS compared to running ROP. However, my range goes from 800 miles to over 1,000 miles and time goes from 4 hours to near 5 1/2!

I told my wife that we could make Osh non-stop and have 45 minutes reserve but she said, "Nope...we need to stop and stretch:)

Best,
 
Thanks for the data points. I love reading about these real world performance numbers, and how they compare to the other planes I'm flying now:

C182: 145Kts @ 14GPH (~12MPG no wind)
Piper Archer 110Kts @ 9GPH (~14MPG no wind)

It's good validation of my decision to build the -10, and motivation to GET IT DONE! I've been seeing -10's reportedly getting between 16-21+ MPG depending on how fast people are pushing them.
 
Ed, speaking of MPG, it's usually around 13-15 running 75% and ROP. It easily goes above 16 MPG running around 68% and LOP in light wind conditions. I have seen over 20 MPG with strong tailwinds as well.

My personal philosophy says that flying's never really inexpensive and since I like the speed, I'd rather spend more and true 202 at 12-14 MPG:)

A good time to capitalize on economy and LOP ops is when you have a 25-40 knot tailwind!

Best,
 
My personal philosophy says that flying's never really inexpensive and since I like the speed, I'd rather spend more and true 202 at 12-14 MPG:)

I agree. It's just nice having a number that you can tell non-aviation people, who don't have a concept of GPH and airspeeds, how efficient this plane is.
 
Why do you run the fuel down so far on the one tank?

Very impressive--I need to stay away from this place or I am gonna end up building one!!
 
I'm trying to learn more about LOP operation and I know this is a primer war type subject but never the less, here we go! Best that I have recently come to understand it, with 70% power you would want to run more LOP than -04F. Should be closer to 25. What are your thoughts on this matter? Red Box = No Fly Zone

At and below about 60% power, there is no red box. Put the mixture wherever you want it.
At about 65% power or so, 100?F ROP to Peak.
At about 70%, 125?F ROP to 25?F LOP.
At about 75%, 180?F ROP to 40?F LOP.
At about 80%, 200?F ROP to 60?F LOP.

Hey Brian good to hear from you. Dont take me as an example of how to run your engine! :rolleyes: I sometimes swim upstream :D

Dan posted this:
imgres


This is testing done by Lycoming. Notice the intake air temp, Cyl head temp, MAP, and Oil Temp.

I know there is a chance that I am running "closer" to detonation than some like to go but like I said I sometimes swim upstream.

There will likely be a lot of people jump on here and "chew me out" but thats ok..it has happened before and it will happen again.....:p I can take it.

Also as noted by someone on PM. Dont get to overly excited about the calculated TAS on the Dynon.

I have made sure all of the inputs are calibrated properly but you can take the OAT, IALT and Berometic pressure and figure the DA from that and you will get a different DA than Dynon has....????? Whasup wit dat???? I asked Dynon what they use for a humidity value in the DA calculation but they have yet to provide me an answer. I assume it is something other than most of the other E6B calculators use. Whether it is closer to right or not I dont know. I do know that if I fly the 3 way course using Kevin Hortons method with the spreadsheet I get the same TAS that the Dynon is showing within a Knot.

Anyway if you use the DA from another E6B and calculate TAS from that and the IAS you will get about 2knots less per this picture.
 
Why do you run the fuel down so far on the one tank?

Very impressive--I need to stay away from this place or I am gonna end up building one!!

I had a heavy right wing and I used fuel differance to see where it balanced and then made an adjustment to correct the heavy wing and on this flight I was re-checking to see how much change I had made.
 
Can I ask a question, I?m a little bit confused.
Why does the flap positioning also have an indication for -5??

Cheers
Sunit
 
Flap reflex.

Hi Sunit...the RV-10's have their flaps in the "reflex" position...three degrees up from the normal in trail position. The wing produces excess lift at cruise speeds and would fly too nose down if the flaps were not raised the three degrees.

It also adds a few MPH to the cruise speed.

Best,
 
I would try and swamp the #5 egt probe with the coldest lop cyl ... Just to make sure the probe is not reading off.
 
Only the -10.

Yep, on all the other RV's, the ailerons are rigged in line with the wing chord, then the flaps are adjusted to match them.

On the -10's, the flaps are adjusted all the way up until the spar touches the wing...3 degrees up and then the ailerons are adjusted to match them.

I believe some Lancairs also have some flap reflex.

Best,
 
I am averaging 15-16 NMPG

at 65%, running smooth, 10-35 LOP, stock engine/mags. Flew approx 700 nm on 48 gallons on our first long xc to Florida. It took us approx 4.5 hours. That is maximum safe range for us and our bladders no matter what Van's numbers are. Injectors not balanced and not planning to balance. Balancing would be good for one specific flying condition/setting which I will never fly. It gets better mileage than our Expedition and no more tractor/trailers blocking both lanes of I-75. At this time fuel cost was about the same whether driving or flying. If fuel goes up I will still fly but just take fewer trips.
 
MPG

Total Nautical Miles = 1358
Total Fuel Used = 96.4
Avg NM/Gal = 14.1
Avg stat. MPG = 16.2

This was from a trip from Mississippi to Virgina to Ohio to Mississippi all in one day.

Includes 3 take off and landings.

I took the MPG widget off my EFIS because Winds effect is so I feel it is not usefull for general knoledge of what milage the airplane acutally gets and does not include take off and landings.
 
I took the MPG widget off my EFIS because Winds effect is so I feel it is not usefull for general knoledge of what milage the airplane acutally gets and does not include take off and landings.

Totally agree that it is just a snapshot of the conditions at the moment.

But I used it as a tool to help learn how to maximize the efficiency of the plane on long cross country trips. Paul Dye had made the suggestion a while before.

I now have also reset the readout to TAS, but while I was using MPG, it was a good way to see exactly what was going on with different flight parameters.
 
Good idea

Totally agree that it is just a snapshot of the conditions at the moment.

But I used it as a tool to help learn how to maximize the efficiency of the plane on long cross country trips. Paul Dye had made the suggestion a while before.

I now have also reset the readout to TAS, but while I was using MPG, it was a good way to see exactly what was going on with different flight parameters.

I see what you mean. Good idea.
 
Took a photo in cruise on a recent flight. Disregard the OAT as the probe is getting some exhaust heat and I need to move it.

I was playing with different power settings and this is just one setup I tried to figure out what is optimal. I was getting better economy with the prop pulled back to 2100 - about 2 gph less and losing 11 knots. I have some more testing to do.

WP20120715-7-L.jpg
 
Took a photo in cruise on a recent flight. Disregard the OAT as the probe is getting some exhaust heat and I need to move it.
Keep in mind that the OAT is used by the EFIS to calculate TAS. If the OAT is reading too high, the TAS calculated by the EFIS will be too high as well. And the wind calculation will be affected - it'll show more headwind than you really have.
 
I am normally looking for a medium economy setting, as opposed to a max speed setting. However, here is another screenshot for comparison. My numbers are certainly a lot lower. I know i can get higher numbers with some more fuel. However, I have verified my sensors, esp. fuel flow and temperature sensors, over 150 hours now to be as accurate as i can get them. Fuel flow is a tricky one to get accurate and trustworthy in my opinion.

My CHTs are clearly a lot lower, so i am assuming i am running quite a bit LOP compared to others here. I am still trying to figure out where exactly to cruise at between speed vs money.

screenshot-20120703-143928-991.jpg
 
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I'd say that 149K and 9 GPH is pretty good economy.

If you went ROP at that altitude, you'd probably pick up 10 knots or so and still be going pretty fast PLUS good economy, since you're only getting 19" MAP.

Best,
 
Thanks Pierre! Hope to meet you in OSH! I will probably gradually increase my speeds and play with higher fuel flows in cruise. I realize on that last flight, I could have burned another 1 GPH which would have cost just another $8 or so which is pretty marginal.

Jae
 
Fuel flow is 11.8 running 179kn TAS at this altitude LOP. I am still testing and contemplating tuning #5 cyl as you can see it is quite a bit leaner than the rest of them and is always the first to peak.

First of all, it looks like your "GAMI Spread" is showing 0.0GPH so that means your injectors were really good straight out of the box.

Brian is correct, at 70% power you would be better off around 25F LOP but these are rough enough numbers. You will find your CHT will drop off running just that little bit less. Drop 1 GPH and you will not lose much speed either.

The MPG will be better under that scenario.

The risk of detonation at that power setting is nil, so don't worry, however for MAXIMUM engine life, and these things will run well past TBO if looked after, is to get the CHT and ICP's down. The two things that affect the life of an engine that you have direct control over. So at this point I should say Temperature and pressure.

www.advancedpilot.com is your next investment.

Don't go looking for a Cookbook for a recipe, you need to learn how to cook and be a Master Chef, then all of this you will actually understand not just know a recipe.

Now Brian, that Red/Green Box looks like a copy paste from something, I wonder where :D ;) I hope you have been studying it. C U Next week.

One last thing with the 179 knots, you may have a generous static source. I would recommend doing a GPS box test and getting this to within 2 knots.

Kevin Horton is the VAF GURU on this topic :)

Jchang
Why are you cruising at 11300'? Anyway you too seem to have a nice GAMI spread of 0.3GPH

Folks, the get spread is interesting, but it is really the fuel flow from first to peak to the last to peak that you need to be focussing on. Are we all good on that?

At the height you are at, cruising with about peak to 10F LOP might be a bit better performance. Your CHT's are good and should be at such low power, but squeeze a few more GPH in there and your MPG will improve :)

These RV10's are awesome machines!:D:D
 
User configurable

Wow, am I the only person to see this, and think------information overload:eek:

screenshot-20120703-143928-991.jpg

Its what you get used to. I had trouble thinking that with my setup when I started but I soon found there were other perameters that I wanted to include in the primary screen and not have to change views to see so I kept adding more and more widjets but now that I have used it for 100+ hrs I know where to look for the information that I need and really it starts to seem fairly simple.

I am sure otheres look at mine at first glance and think the same.

The cool thing is you can configure what you want.:)
 
One last thing with the 179 knots, you may have a generous static source. I would recommend doing a GPS box test and getting this to within 2 knots.

Kevin Horton is the VAF GURU on this topic :)

referance post #9 the method by Kevin agrees with the TAS on the Dynon.

Also Ref. this http://www.vansairforce.com/community/showthread.php?t=88595

I still dont know what I am looking at for sure when I see the TAS number on my EFIS:rolleyes::rolleyes::rolleyes:

I go by Kevins method. seems more stable to me until convinced otherwise.
 
So why keep pushing the Red Box list for NA Lycomings? Pure cookbook, and misleading. Actual dyno data demonstrates percent power is a poor metric for detonation control:

The red box is far more than just a detonation control issue, but I assumed you understood that.

It is not pure cookbook at all. Cookbook would be "Run at 23/2300 and at 10.5GPH" That is a recipe that someone might follow blindly. The APS graphs are far from this.

As for being very conservative on a NA Lyc or CMI, this is true of a conforming engine, however, CHT and ICP are the things that will affect engine life, and sure Lyc's go well past TBO if looked after, and as most RV builders are keen to save a penny, over the long run, if you run your Lycoming, as per the graphs, you will save fuel, you will have good speed and range and you will have lower stress on your engine components.

Its that damned simple.

Your posts are not doing anything to help the under educated, you are more than capable of making your own operating decisions, but many here need some good education, and then let them work it out for themselves. If you had any real respect for George and co, you might actually support their education campaign. And by the way, George has not made a cracker out of me, not even via APS seminars, his generous assistance and hospitality has far exceeded the couple of dollars he may have collected as a result of my fees. I owe him.

In fact, it will not be too far down the track when we will all owe him big time for getting G100UL to the pump. But that is another story.
 
This isn't about George, a very smart fellow indeed. And what does "cracker" mean in Oz?

Heard an interesting definition of "cracker" while on Sanibel Island last March.

In days gone by before railroads, cattle were driven up the beach of northwest Florida to market and cowboys kept the critters from wandering off by "cracking" their bull whips over them, hence they became known as "crackers".

Now I suppose an RV pilot could be a cracker when pulling the throttle back for landing as there frequently is a popping noise bordering on cracking. :)
 
heheheheh

Sorry about that.

Not made a Dime, Nickel, a brass razoo (for Pierre's benefit perhaps)

The reason I say this is too many folk wonder if there is money involved when one supports something.

And I note it is an election year here.....lots of money talking on the TV :)
 
Its what you get used to. I had trouble thinking that with my setup when I started but I soon found there were other perameters that I wanted to include in the primary screen and not have to change views to see so I kept adding more and more widjets but now that I have used it for 100+ hrs I know where to look for the information that I need and really it starts to seem fairly simple.

I am sure otheres look at mine at first glance and think the same.

The cool thing is you can configure what you want.:)

Weasel... that has been exactly my evolution as well. On my first flights, I had to cover up most of the EFIS display, as all the whiz bang flashing and blinking was distracting me from flying the plane and looking out the window.

Eventually, I too got tired of switching views for the info i wanted. Instead I crammed as much useful info as i could into a single screen. I hope to cram in more. You just get used to looking at what you want at different phases of flight.

Unfortunately, for most of the non-flying public, they are infinitely more impressed when they see a panel full of round steam gauges since that's what flying a real airplane looks like.

An EFIS screen looks too much like their kids playing XBOX. :p

Jae
 
Following with interest

Oz,
Welcome to the neighborhood (globally speaking).:D
What do you find objectionable to cruising at 11500 in Jchang's post?
Where do you find your most efficient (Best MPG) altitude?
My guess on Jchang's cruising altitude besides efficiency was LA's Class Bravo airspace top at 10000 feet and some "hills" topping 9000 feet in that area.
 
Howdy! on a train to DC right now....beats your NY cabs and airports :eek:

Well not that it might matter here in the US, but once above 3000 AGL we are meant to be flying hemispherical levels and if VFR with that heading 11500'

But hey I am just being picky :D

I have found up around FL130 is pretty good. Fuel flows down around 36-37LPH and TAS close to 160 knots
 
Under Cowl

For those of you that asked about the cooling system at oshkosh and wanted to see some of the mods that we did for a (hopefully) more efficent cooling air system. Here are some pictures.

IMAG0712.jpg

IMAG0713.jpg

IMAG0714.jpg

IMAG0715.jpg

IMAG0716.jpg

IMAG0717.jpg
 
Finding economy cruise

My RV-10 (the one with the sunsets painted on it) has an O-540-B4B5 engine, 235 HP with carb, so is a little different than most. Peak RPM is listed as 2575. It is low compression so I can use autogas at $4.25/gal from a nearby airport. I recently discovered a scanned power curve chart for my model of engine and it shows the best fuel consumption is around 2250 rpm WOT. So, this past month on various flights from the Oregon coast to/from OSH and BFI I verified that I am now getting trip averages of 10gph with 155-160KTAS at 8500-10500 ft.

So, that gets my statute mpg to be 18.4 and cost per mile using autogas to be 24c/statute mile. Pretty darn good, and better with a tailwind!

Doug.
 
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