Fuel Flow High

[SkippyDiesel]

@SkippyDiesel are you the original builder of your plane?

Yes & No - I purchased the incomplete, plans built, Sonex Legacy from the original builder and finished it. Under Australian rules, I am listed as the builder. It's been in the air for 132 hrs now.
The aircraft came to me as an almost comprehensive "kit" in that I have had to purchase very little - the fuel metering system being part of the initial purchase.
While I understand that having the two Red Cubes has the potential to improve the accuracy of fuel flow (an aid to engine power setting) I am beginning to wonder if its complexity outweighs its benefits.
My last aircraft had a single, impella style, fuel flow metering system - "easy as falling of a log" to calibrate. Gave reliable total fuel used and useful, inflight, indicated flow.
Before this aircraft was flown, I did fuel flow calculations - the return fuel line delivers, through a restrictor jet, a fairly consistent 7L/hr, back to the header tank. Rotax publish expected fuel consumptions at various power settings - the figures give me a baseline from which to assess the inflight fuel flow readings - they are out.
For total (actual) fuel used I just start from full tanks, fly, refuel to full tanks and adjust metering system (pulse rate) to reflect actual fuel used - seems to work.

Back to Dynon/Red Cubes;
From my reading of the instructions, the return line metering would be automatically deducted from the main line fuel delivery. I assumed that as long as this was a consistent deduction, I need only calibrate the main line. This seems to be incorrect.

So the position now is;

• I have an accurate fuel used reading.
• I need to calibrate the return line flow - what impact will this have on my main line fuel flow callibration?
• To adjust the return line there is no filling of tank/refilling - Other than the filling of a bucket (static) how do I judge the accuracy of the return line calibration & adjust up/down?

 

[chriscalandro]

With a return line, more than likely the only way to meter the fuel is with 2 transducers.

This really is not that complicated at all. Is there a reason you are so against disconnecting the lines, pumping into a calibrated measurement, and documenting each correct number? Not to mention the red cube should have came with is calibrated ppg value….

 

[SkippyDiesel]

"With a return line, more than likely the only way to meter the fuel is with 2 transducers."

Not correct! Read my comments above. Further I am reliably informed that several aircraft manufacturers' (eg Tecnam) install one sensor (Red Cube) and adjust the reading to accommodate the return line fuel flow. While this may not be as accurate as a two sensor system it its functional.

"Is there a reason you are so against disconnecting the lines, pumping into a calibrated measurement, and documenting each correct number?"

Read my comments above - I have a reliable 7L/hr return line flow derived from multiple tests.

".....red cube should have came with is calibrated ppg value"

Dynon give this as 68000 pulses - Note: this is a baseline figure that should be calibrated for each installation.

Not from this Forum- It has been suggested to me that I should check that the return line fuel sensor is actually working

 

[chriscalandro]

It most definitely is correct. With a return line if you want an accurate reading you need to meter the fuel at both sides.

Knowing the fuel flow the engine uses is only useful for verifying your configuration. It has absolutely nothing to do, and is not useful at all when it comes to configuring your red cubes.

Dynon didn’t make the red cube. They only provide basic starting guidance based off experience and then tells you the necessity configure it properly.


I don’t understand why it’s so difficult for you to do this very simple process. To be honest it doesn’t make any sense why you would be so combative, and resilient on doing the proper process. At this point you have been given all the knowledge tools and information, A few times.

 

[SkippyDiesel]

Chris - I know (hope) you are attempting to be helpful, unfortunately you are not.

• Your statements do not address the question.
• Are far to general in nature, repetitive & pedantic in tone.
• You do not read or take into account, the responses made to your suggestions.

For this topic, this is my last response to you.

All the best

 

[chriscalandro]

There is a right way and wrong way.
You have been provided VERY SPECIFIC answers to your questions.

They are repetitive, because the correct and proper information has not changed.

The responses given demonstrate a lack of understanding of the content provided and the unnecessary search for a shortcut or loophole.


This entire thread you are trying to skirt around the right way (which isn’t even difficult) in search of shortcuts.

There are no shortcuts.

At this point I have to question the integrity of not only this one simple calibration, but your entire build.

You show a complete lack of understanding about the basic systems

You search for shortcuts introducing short comings and discrepancies.

You get basic facts and general knowledge wrong.

I STRONGLY urge you to seek support and help for your build as you have demonstrated (in my opinion) the lack of knowledge and skill to complete and understand this very simple task. I suspect based on this your build likely has many other deficiencies, potentially creating a hazard to not only yourself, but life and property on the ground.

While this may be experimental, you still have an obligation to follow standard practices and procedures to reduce these risks.

Again, seek assistance not only with this, but with any assembly or construction you may have completed yourself without oversight.

 

[swatson999]

And you all wonder why some of us throw up our hands in exasperation and exclaim "just RT*M".

Get it now?

 

[chriscalandro]

And you all wonder why some of us throw up our hands in exasperation and exclaim "just RT*M".

Get it now?

lol. I did my best to not go that route. It’s very clearly explained in there.

 

[swatson999]

lol. I did my best to not go that route. It’s very clearly explained in there.

As are most things, but even the ones that aren't are usually pretty obvious.

 

[SV_Classic]

And you all wonder why some of us throw up our hands in exasperation and exclaim "just RT*M".

Get it now?

oooh, still trying to grind the axe. the strategy for this type of situation is to not respond after the thread has stopped being productive. problematic people will irk others and you have to be big enough to just scroll on by. the back and forth is not productive and it kills the vibe at the site.

@SkippyDiesel it will be to your benefit to just say thanks when people don't answer your question but when you get snippy about it, you really aren't going to get the help you need.

I thanked someone for their help and mr swatson got bent out of shape because I didn't explicitly thank him too even though his reply wasn't as helpful. everyone is way too eager to bash heads here, it's a cultural thing that forms in forums and it isn't helpful. i'm just trying to learn about my skyview classic from everyone else's questions but the drama makes it harder than it needs to be.

 

[SV_Classic]

lol. I did my best to not go that route. It’s very clearly explained in there.

part of helping someone is trying to understand what it is that they aren't understanding and then pinpointing your answer to help fill that gap. he expressed that your answer wasn't clear and you repeated it and then dug in without any willingness to offer more basic info. he wasn't right to get shitty with you but he didn't understand your answer and your reply was to post the same answer again so I can see how learning wasn't accomplished.

 

[chriscalandro]

part of helping someone is trying to understand what it is that they aren't understanding and then pinpointing your answer to help fill that gap. he expressed that your answer wasn't clear and you repeated it and then dug in without any willingness to offer more basic info. he wasn't right to get shitty with you but he didn't understand your answer and your reply was to post the same answer again so I can see how learning wasn't accomplished.

Learning wasn’t accomplished because learning wasn’t possible. Just because you don’t understand the answer doesn’t mean the answer changes. This is airplanes not kindergarten and we aren’t giving away participation trophies.

Fuel exhaustion is a significant problem in GA.

 

[chriscalandro]

oooh, still trying to grind the axe. the strategy for this type of situation is to not respond after the thread has stopped being productive. problematic people will irk others and you have to be big enough to just scroll on by. the back and forth is not productive and it kills the vibe at the site.

@SkippyDiesel it will be to your benefit to just say thanks when people don't answer your question but when you get snippy about it, you really aren't going to get the help you need.

I thanked someone for their help and mr swatson got bent out of shape because I didn't explicitly thank him too even though his reply wasn't as helpful. everyone is way too eager to bash heads here, it's a cultural thing that forms in forums and it isn't helpful. i'm just trying to learn about my skyview classic from everyone else's questions but the drama makes it harder than it needs to be.

Also, I don’t accept lectures from pots and tea kettles.

 

[SV_Classic]

sorry Chris but you're part of the problem. I understand that that won't penetrate but the guy didn't understand and you just repeated your answer like it was his problem that you weren't going to go any further. I tried to help but he was already triggered by his exchange with you.

EXPERIMENTAL airplanes are meant for learning as much as flying. People with zero experience have been doing this for many many decades and, yes, it's scary to think what goes on out there in the privacy of a hangar but the FAA has created this category for learning and experimentation. Dynon is selling avionics for experimental aircraft so this is the kind of thing you are going to get here. You can either participate and help people to learn the basics (if need be) or you can talk over them and create drama.

 

[chriscalandro]

Learning and experimentation is one thing, but so are minimum standards and airworthiness.

A lot of times what happens is someone will buy something experimental and airworthy and modify it in a way that is no longer airworthy.

While fuel computation might not be an airworthiness issue, fuel indication is.

Again, the answer doesn’t change because you don’t understand. Especially when the answer really isn’t complicated.

Weather provided from myself or Dynon, the real correct answer based on the response is to seek help from someone that knows how to do this.

This is also what potentially makes this so dangerous- not seeking help or understanding when to seek help.

The last thing we need is for this airplane to meteor into someone’s house and then someone find a thread of someone clearly not understanding the basics of what they’re doing. That’s the fast path to regulation.

If you think the answer provided was “talking over them” - you are part of the problem. The answer was very simple and not complicated in the least.

 

[SV_Classic]

Chris, I suggest you go right away to Dynon and tell them the grave danger they are creating and to stop selling avionics for non-certified aircraft. Then call Okalhoma City and tell the FAA that they should immediately stop licensing experimental aircraft as the danger is too great.

Go check out Vansairforce.com, there are like five million people there of various levels of understanding and experience, actually helping each other! It's too bad as you have knowledge to offer but your interest isn't really in helping others to learn as much as it is in demonstrating that you simply have knowledge.

The whole point of a forum site like this is to promote learning, it's really simple if you just think about it for a second.

 

[chriscalandro]

Here. This is what was wanted.

 

[SV_Classic]

Learning wasn’t accomplished because learning wasn’t possible.

I can say the same thing about you sir

Social media isn't for everyone.

 

[swatson999]

I can say the same thing about you sir

Social media isn't for everyone.

Look, everyone, it's the

 

[SV_Classic]

Another great contribution to the community. Bravo