Date   

Re: Fuel system anomaly video [1 Attachment]

Matthew Curcio
 

So last night I figured I would check the float height. I did and it seemed fine. I bent it up just a bit and while I was down there putting it on I figured I mine as well bend the vent up a little to like someone had mentioned. I took off and flew around and I could not get the engine to run rough. I decided to bend it down even more to get it further away from the fuselage but still at the same angle and after 1.5 hours of flying today it is stills fine. The weird vacuum bubbling looking sensation in the sight glass did not occur - except one time. I was diving and got up to 200 and it started to occur but didn't start tuning rough. My theory now is that there is a low pressure area behind the bottom of the cowl and it migrates back further the faster you go or some kind of weird airflow going on at least. I'm thinking that at some point I would like to locate the vent nearby where the pitot is. That should prevent this issue from ever occurring against. I've now got 2 hours on it without this issue. I'm still not confident in it but I feel like I'm on to something. 


On Sep 10, 2017, at 8:29 PM, jay@... [Q-LIST] <Q-LIST@...> wrote:

 

Matthew, 


I suspect a slightly different problem. Once you enter high speed level line of flight, there is a low pressure area that migrates to an area near the top rear of the canopy, where the canopy frame meets the seat back bulkhead. This is usually not an airtight seal. See the red area in the attached picture (low pressure). 

When you are at lower speed and a higher angle of attack, this same low pressure area is closer to the front of the canopy where plex is a solid piece and is consequently airtight. I suspect that when you reach 140-ish the low pressure area serves to de-pressurize your cabin through the crack between the canopy and the bulkhead. 

My thought is that the top of your fuel sight gauge (main tank) is in communication with the cabin pressure. If there is a small crack in the gauge tube inside the tank, then the low pressure in the cabin could draw air through the crack and into the standing fuel gauge column, showing up as bubbles. Regardless of the source of the bubbles (could be "boiling" fuel as previously suggested), such communication will tend to depressurize your tanks, and may be sufficient to overwhelm the ram air tube, especially if the ram is poorly positioned.  

If I am correct, I think the only thing to do would be to install a fuel pump downstream of the header that can be used as needed to send pressurized fuel directly to the carb. The long term fix would be to install gauges that do not communicate with cabin pressure, so the ram air will be more effective. 

My two cents.

Cheers,
Jay Scheevel, Tri-Q, still building. 

<oblique_side_view_pressure_distribution.jpeg>


Re: Jon Finley

Jon Finley
 

Ryan, if you don't have the Ellipse issues of Contact! Magazine you should get them from Pat. They are VERY good!


Re: Jon Finley

Jon Finley
 

Hi Ryan, 

I did a lot of prop theory research a decade ago - read everything I could find. However; I am no expert.  Thanks to Pat Panzera for connecting me with Paul. Everything he wrote and said about prop design made sense to me. I believe it was also proven in the air by those that took the time to construct what he designed.  Sadly, that was a very significant effort. Especially significant since one should expect to carve three or more props to nail it down. This may not be true if all of the components are fairly well know (HP & drag curves).

Paul was interested in my setup as I was running very high prop rpm (3500) and was very noisy. The first Ellipse prop I built (Paul designed) showed signs of being massively better than the modified warp drive prop I had been using.  However; it was over pitched. I cannot remember the exact details now - something like 20 mph faster at cruise a cruise rpm several hundred less than normal. Of course, being down on rpm meant that climb suffered terribly.  Paul modified the design and I carved a second prop.  I made it as far as some ground testing with that prop but no further due to life issues.

Jon


Re: Jon Finley

Patrick Panzera
 

oops, sorry, it was a Lycoming O-235, not Continental. 

Pat

On Sun, Sep 10, 2017 at 9:23 PM, ryan goodman elboy0712@... [Q-LIST] <Q-LIST@...> wrote:
 

That's awesome


 

It was during one of the AWESOME Livermore tandem wing gatherings. I invited Paul to join us, so he flew in with his highly modified Lancair 235 - which was powered by a stock Continental O-235. Jim's O-200 is more than stock so they're "close enough" in power, but Jim couldn't use a spinner - accounting for a few mph lost.

On Sep 10, 2017 1:06 PM, "logistics_engineering@... [Q-LIST]" <Q-LIST@...> wrote:
 

No, he took off his plane to let me try it out.

Jim Patillo
N46JP - Q200



Re: Jon Finley

ryan goodman
 

That's awesome


On Sun, Sep 10, 2017 at 3:35 PM, Patrick Panzera editor@... [Q-LIST]
wrote:
 

It was during one of the AWESOME Livermore tandem wing gatherings. I invited Paul to join us, so he flew in with his highly modified Lancair 235 - which was powered by a stock Continental O-235. Jim's O-200 is more than stock so they're "close enough" in power, but Jim couldn't use a spinner - accounting for a few mph lost.

On Sep 10, 2017 1:06 PM, "logistics_engineering@... [Q-LIST]" <Q-LIST@...> wrote:
 

No, he took off his plane to let me try it out.

Jim Patillo
N46JP - Q200


Re: Airport Closed - Hurricane.

Mike Dwyer
 

This is going to be the biggest $ damage ever.  FL is a wreck!
Mike

On Sep 10, 2017 8:53 PM, "Mike Dwyer" <q2pilot@...> wrote:
Wind is blowing near 80 mph gusts.  Will be this way for 5 hours.  Looks like the eye is going to pass well east of us and I think the hangar will not get flooded with the wind this direction.  Lost power at 6:30pm so it's just flat dark and windy!
Will be curious to see what the place looks like in the morning!
Mike Q200 N3QP

On Sep 10, 2017 8:30 PM, "jay@... [Q-LIST]" <Q-LIST@...> wrote:
 

Wishing you the best, Mike. Nature is interesting, sometimes too much so. Hang on tight. 


Cheers,
Jay Scheevel



Re: Airport Closed - Hurricane.

Mike Dwyer
 

Wind is blowing near 80 mph gusts.  Will be this way for 5 hours.  Looks like the eye is going to pass well east of us and I think the hangar will not get flooded with the wind this direction.  Lost power at 6:30pm so it's just flat dark and windy!
Will be curious to see what the place looks like in the morning!
Mike Q200 N3QP

On Sep 10, 2017 8:30 PM, "jay@... [Q-LIST]" <Q-LIST@...> wrote:
 

Wishing you the best, Mike. Nature is interesting, sometimes too much so. Hang on tight. 


Cheers,
Jay Scheevel


Re: Airport Closed - Hurricane.

John ten
 

Good Luck, Mike.


Re: Airport Closed - Hurricane.

John ten
 

Good Luck, Mike.


Re: Airport Closed - Hurricane.

Jay Scheevel
 

Wishing you the best, Mike. Nature is interesting, sometimes too much so. Hang on tight. 

Cheers,
Jay Scheevel


Re: Fuel system anomaly video

Jay Scheevel
 

Matthew, 

I suspect a slightly different problem. Once you enter high speed level line of flight, there is a low pressure area that migrates to an area near the top rear of the canopy, where the canopy frame meets the seat back bulkhead. This is usually not an airtight seal. See the red area in the attached picture (low pressure). 

When you are at lower speed and a higher angle of attack, this same low pressure area is closer to the front of the canopy where plex is a solid piece and is consequently airtight. I suspect that when you reach 140-ish the low pressure area serves to de-pressurize your cabin through the crack between the canopy and the bulkhead. 

My thought is that the top of your fuel sight gauge (main tank) is in communication with the cabin pressure. If there is a small crack in the gauge tube inside the tank, then the low pressure in the cabin could draw air through the crack and into the standing fuel gauge column, showing up as bubbles. Regardless of the source of the bubbles (could be "boiling" fuel as previously suggested), such communication will tend to depressurize your tanks, and may be sufficient to overwhelm the ram air tube, especially if the ram is poorly positioned.  

If I am correct, I think the only thing to do would be to install a fuel pump downstream of the header that can be used as needed to send pressurized fuel directly to the carb. The long term fix would be to install gauges that do not communicate with cabin pressure, so the ram air will be more effective. 

My two cents.

Cheers,
Jay Scheevel, Tri-Q, still building. 


Re: Fuel system anomaly video

Mike Dwyer
 

Are you using Ethanol based fuel?  If so, STOP.  Could something be heating your fuel line?  Is you fuel line metal and near the exhast?
Mike



On Sun, Sep 10, 2017 at 10:33 AM, Matthew Curcio mlcurcio89@... [Q-LIST] <Q-LIST@...> wrote:
 

Okay guys I got a video! Prepare to be perplexed.

So a background to this. I put a factory overhauled carb on here and that took car of the power loss on take off issues. I then found an issue where when I am going above 140mph I get a fuel starvation issue where the engine leans out and will begin knocking even. It does not do it consistently or predictably. Pulling carb heat will smooth everything out and make it run perfectly fine. 

I have also noticed this odd anomaly on the fuel system gauges. The splashing in the header glass is not continuous but the bubbling in the main gauge continued until I landed. I have to wonder if the issue above is related to this but I don't see how they could be.



Re: Jon Finley

Patrick Panzera
 

It was during one of the AWESOME Livermore tandem wing gatherings. I invited Paul to join us, so he flew in with his highly modified Lancair 235 - which was powered by a stock Continental O-235. Jim's O-200 is more than stock so they're "close enough" in power, but Jim couldn't use a spinner - accounting for a few mph lost.

On Sep 10, 2017 1:06 PM, "logistics_engineering@... [Q-LIST]" <Q-LIST@...> wrote:
 

No, he took off his plane to let me try it out.

Jim Patillo
N46JP - Q200


Re: Jon Finley

Jim Patillo
 

No, he took off his plane to let me try it out.

Jim Patillo
N46JP - Q200


Re: Airport Closed - Hurricane.

Mike Dwyer
 

I just saw some video of the local beaches and Tampa Bay.  The water is being sucked out!  As long as the Hurricane stays to the east of us the hangar should stay dry.  As long as we have power I will be posting video from the house hourly on my youtube channel.  Don't have much else to do...


Mike n Liz 




Re: Jon Finley

ryan goodman
 

Wow..yeah that is a lot. Do you still have the prop he gave you?


On Sun, Sep 10, 2017 at 1:31 PM, logistics_engineering@... [Q-LIST]
wrote:
 

Paul Lipps was a friend of mine and let me use the Ellipse prop off his Lancair for testing on my Q200.
It was proven at Reno that his props would increase speed. Don't recall the name of the race plane but it went significantly faster with Paul's prop on it.

Paul's prop was a 62/78 and was a little to much for my 120HP Q but I did pick up several knots, just didn't make enough rpm to produce the HP to go really really fast.

I wanted to have a 60/72 made but Paul wasn't making them. I asked Craig to make one for me but he wanted 3k to do it because of the complex mfg. I didn't persue it further after Paul died.

Jim Patillo
N46JP Q200


Re: Jon Finley

Patrick Panzera
 



On Sep 10, 2017 12:30 PM, "logistics_engineering@... [Q-LIST]" <Q-LIST@...> wrote:
 

Paul Lipps was a friend of mine and let me use the Ellipse prop off his Lancair for testing on my Q200.
It was proven at Reno that his props would increase speed. Don't recall the name of the race plane but it went significantly faster with Paul's prop on it.



Tom Aberle's Phantom. 

Smoked the biplane class for 3-4 years in a row, going faster each time. Started with a three blade Elippse prop, and is now running 4 blades. 

Last year he didn't run Reno, but he's there thus year with his Elippse prop. 

Pat


Re: Jon Finley

Jim Patillo
 

Paul Lipps was a friend of mine and let me use the Ellipse prop off his Lancair for testing on my Q200.
It was proven at Reno that his props would increase speed. Don't recall the name of the race plane but it went significantly faster with Paul's prop on it.

Paul's prop was a 62/78 and was a little to much for my 120HP Q but I did pick up several knots, just didn't make enough rpm to produce the HP to go really really fast.

I wanted to have a 60/72 made but Paul wasn't making them. I asked Craig to make one for me but he wanted 3k to do it because of the complex mfg. I didn't persue it further after Paul died.

Jim Patillo
N46JP Q200


Re: Jon Finley

ryan goodman
 

No didn't find a used one. And not really thinking of carving my own. Though I'll admit the idea crossed my mind. My buddy has a cnc machine so........ That said; I think it's mostly an interest from a curiosity perspective. The experimental community tends to be full of folks who love to talk about what doesn't work, or what is common knowledge, that they themselves have picked up over the years and preach as gospel. To me that may be true often and yet still wrong under certain conditions. Because of this I think that the mentality may stifle innovations and potentially great leaps forward. So, when I come across things that show someone breaking down walls(even small or partial victories) against conventional "truths", it really piques my interest and I want to know more. I'm am engineer, so numbers and explanations why kind of calm my anxiety in this experimental world. There's a lot of builders out there who do amazing things just on the things the community "knows to be true" with little engineering knowledge at all. I think that's wonderful, but it still leaves me seeking an explanation. I don't do well pushing the "I believe" button. I need to know why. So for me, it's an exercise in finding out which parts of Paul's design broke convention and worked, and which parts just made for canon fodder. And I want to know why.......sorry for the long reply, but I felt it necessary to explain my pursuit of this. /Ryan


On Sun, Sep 10, 2017 at 8:39 AM, qplustwo@... [Q-LIST]
wrote:
 

Ryan,

Just out of curiosity, what's the interest in the Ellipse prop? As they aren't made any more, did you happen to come across a used one or are you thinking of carving your own?

-MD


Re: Fuel system anomaly video

Earnest Martin <MartinErni@...>
 

Matthew, If you can run full power in a nose up position but not level or nose down your vent may be in a low pressure area when you level off and the fuselage AOA changes. I chased that for weeks after changing the cowl exit which affected the pressure aft of the firewall. The pressure may be so low in the tanks that the fuel is changing from liquid
to gas (bubbling).
Earnest Martin
40 Glen Cove Drive
Arden NC 28704-3219
828-230-5378
martinerni@...

On Sep 10, 2017, at 11:51 AM, Paul Fisher rv7a.n18pf@... [Q-LIST] <Q-LIST@...> wrote:

http

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