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Posted
7 hours ago, AME LLC said:

The acclaim climb checklist calls for low boost pump above 18,000 for vapor suppression. So that was on the whole time.   I just learned what the quote button does.  It’s kinda like the reply button..  oh nevermind. 

Well that kills that idea, but I like the idea of adapting the GTSO-520 heated spider. Still think there needs to be some work on the under floor plumbing heat wise however. 

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Posted
Posted

Were you whistling the tune from Always like Richard Dreyfus?  Lol. Glad you and plane are unscathed. Pretty sweet airmanship sir. 

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Posted
34 minutes ago, Echo said:

Were you whistling the tune from Always like Richard Dreyfus?  Lol. Glad you and plane are unscathed. Pretty sweet airmanship sir. 

Hahaha!  Funny you say that. I fly and maintain an A26 here in Seattle called Sexy Sue. For sure I was whistling!  LOLIMG_7617.png.2cab963158cf86a6d2130e939fbfe2b4.png

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Posted

I wonder if a change in baffling would allow some passive heating of the spider. As long as it didn't negatively affect other things. The Acclaim's cooling design seems great in general, passively managed and fairly reobust (though cylinder #5 just sent me an angry text)...

 

Posted

I also have come to understand that Victor and specifically their "Black" option is one of the best engine rebuild options you can get. What's been your experience, and do they make any mods to the system beyond polishing intake ports, etc? 

 

 

Posted
4 hours ago, AME LLC said:

Hahaha!  Funny you say that. I fly and maintain an A26 here in Seattle called Sexy Sue. For sure I was whistling!  LOLIMG_7617.png.2cab963158cf86a6d2130e939fbfe2b4.png

If you can handle an A-26, you got it going on. If you can handle a B-26 you really got it going on.

Posted

It seems like there’s a few things at work here, but I flew last week in the FLs around the area @AME LLC had the issue and it was cold. Real cold. Like isa -10 or so.  Maybe-38c at fl210? So some amount of water possibly in the fuel, maybe higher humidity, very cold air hitting the fuel spider… it kind of adds lots of factors.

Real nice job using atc and your systems (terrain page) to find a safe landing spot!

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Posted (edited)
On 11/27/2024 at 2:17 AM, KSMooniac said:

Any idea what the fix might be?  Something like "carb heat" but for a fuel injected engine?  

Isopropyl 1% should help with this (M20K 231 says 3% but it seems a lot, 1% is more than enough), it’s not clear how it helps at -30C but it seems to work (maybe keeping full tanks, draining as much water and keeping high power)

If the engine quits due to fuel icing, it will not restart no matter how one fiddles with it, even after many attempts, I tried many times in twin one day, it only started when warm 1h after landing. I recall another pilot had same issue with same aircraft although it was a double engine failure attributed to fuel icing, the design was really poor without water drains under main & aux fuel tanks, only gascalator drain inside cockpit, and the POH never mentioned anything about using isopropyl, so any water there will freeze one way or another…

I was told turbo engines do not restart until dense air is reached, I have not tried but it looks plausible 

This makes me wonder if some practices like running tank dry (some pilots use this for “max range”) is a good idea when it’s colder than -10C, with all dirt and water in lower parts, especially in IMC? it’s scary to try even in twins…

Amazing job AME LLC ! (stunning views for that stop along the way)

Edited by Ibra
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Posted

Isopropyl alcohol becomes increasingly viscous with decreasing temperature and freezes at −89.5 °C (−129.1 °F).[9] Mixtures with water have higher freezing points: 99% at −89.5 °C (−129.1 °F), 91% (the azeotrope) at −75.5 °C (−103.9 °F), and 70% at −61.7 °C (−79.1 °F).[13]
 

From Wikipedia

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Posted

Well, I never once thought fuel icing would be an issue once cruising along at altitude.

I’m glad AME LLC let us know and so many others chimed in. Does anyone have any idea at what temperature this becomes a problem? If so, I will add Heet or IPA anytime I plan to fly when the temperature at my cruising altitude is X or below.

Posted (edited)
On 11/29/2024 at 2:06 AM, A64Pilot said:

I think possibly the fix is what the Army did decades ago, measure the entrained I think it’s called water and if it’s above some number, remove it before the fuel is dispensed.

Think that could happen at the self serve fuel pumps? 

We used to do the opposite: add water to test and remove ethanol from SP98/E5 fuels we get from car pumps (sort of AKI fuel with alcohol in France), then once water+ ethanol are filtred from the buttom we use the top fuel in ultra-lights and uncertified machines (Turbulents, Jodels),  these can handle lower octane, however, unlike Rotax, they hate ethanol 

Water gets drained and any parts that stays up are not a problem for those flights: ne does not fly VFR  ultra-lights (especially, open cockpits) in IMC under -30C near FL200, so fuel icing is not a concern, the main concern is losing rubber parts like engine driven fuel pump on downwind without an electrical pump as backpup :lol: at ambient temperatures, all you need is checking for visible water traces as you drain

I imagine doing the reverse would give us an indication of water: mixing fuel samples with ethanol then see if water + ethanol separates at the lowest part

As a side question, does isopropyl + water separate at ambient temperatures like ethanol + water do? 

Back to fuel icing in Mooney, it's not clear what is the threshold for % of water as function of temperature?

This has some implications on how far one can go to mitigate this:

* Is it enough to drain fuel sample on lowest points and inspect for water visually? and what's the threshold of water % that can be seen visually at ambient temperatures? 

* One can test the presence of water % at ambient temperatures, is that enough at -30C? 

* How much % isopropyl will be required? 1% looks like a lot for those who care about regular use and expensive Mooney tank sealants (engine is fine with 1%) 

On ethanol + water, some stuff is written here, I need to start some chemistry experiments in my hangar on fuel samples with all the ingredients this month :lol:

https://www.bellperformance.com/blog/bid/114018/phase-separation-water-e10

My understanding, this is one of the reason why fuel in cars with ethanol have "official expiry dates", altough, it does not matter much in practice 

 

 

 

 

 

Edited by Ibra
Posted (edited)
3 hours ago, Ibra said:

This makes me wonder if some practices like running tank dry (some pilots use this for “max range”) is a good idea when it’s colder than -10C, with all dirt and water in lower parts, especially in IMC? it’s scary to try even in twins…

 

I’ve heard this all the time, it seems to be a opinion of most.

But here is the thing, the fuel pickup is fixed, it’s drawing from hopefully the very bottom in order to reduce unusable fuel. 

Assuming we are talking about contaminates that don’t float in fuel they sit on the bottom and are suctioned up the fuel line whether the tank is full or empty, emptying one has no effect on sucking up water or other heavier than fuel contaminates. Now anything that floats of course won’t be until the tanks pretty much run dry, but how much “stuff” floats in fuel?

Sumping the tanks if they are well designed will alert you to any contaminates, especially water and eliminate them. “Free” water only of course, water dissolved in fuel it can’t, and that’s in my opinion another reason to not add the alcohol until your ready to fly, if it sits in the fuel over time it’s absorbing the water from the atmosphere. The atmosphere gets into the tanks from temperature changes, as temps drop the tanks inhale if you will and exhale when temps rise.

An exception to this is possibly some bladder tanks, I had a C-210 that had apparently a wrinkle in the left bladder because you could sump it and get nothing, rock the wings and then get a little water.  

I was taught by a very experienced ferry pilot that running one side dry isn’t to increase range, because of course it has no effect on range, but rather so that you know there is nothing left on that side, otherwise you’ll think worst case I have a little left that you may not.

Edited by A64Pilot
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Posted (edited)
57 minutes ago, Ibra said:

Does isopropyl + water separate at ambient temperatures like ethanol + water do? 

I believe so, but we add alcohol to make the water combine into an emulsion and mix with the fuel in our aircraft.

Other than water trapping filters and recirculating fuel I don’t know of any other way, filtering your removing the water, adding alcohol your making sure that there will be no free water dropping out of solution in cold temps.

Phase separation occurs when the fuel gets saturated and the water that can no longer be contained drops out of solution, it gets saturated because alcohol is hydroscopic, that is it readily mixes with water and will absorb water from the atmosphere over time, as the fuel temp drops and I believe maybe as atmospheric pressure drops the amount of water that can be held in solution decreases, not sure about dropping atmospheric pressure but remember reading that years ago.

By adding alcohol to our aircraft fuel prior to flight, we are alcohol “rich” that is we have a mixture that can absorb more water than is present, get alcohol rich enough and fuel won’t phase separate in cold temps.

I’d follow the POH, if it said 3% then that’s what I’d add if I was concerned

I know it’s probably obvious, but there is a specific alcohol that you must use, you can’t or shouldn’t use any other.

Years ago I went on a mission if you will to find the number of aircraft crashes from aircraft burning E10 gasoline, in short I couldn’t find any, but I know for a fact that many, many aircraft are burning it.

I’m not abdicating burning it because it’s dis allowed, but it was interesting that at that time I couldn’t find any crashes attributed to it.

Edited by A64Pilot
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Posted
24 minutes ago, A64Pilot said:

I believe so, but we add alcohol to make the water combine into an emulsion and mix with the fuel in our aircraft.

Other than water trapping filters and recirculating fuel I don’t know of any other way, filtering your removing the water, adding alcohol your making sure that there will be no free water dropping out of solution in cold temps.

Phase separation occurs when the fuel gets saturated and the water that can no longer be contained drops out of solution, it gets saturated because alcohol is hydroscopic, that is it readily mixes with water and will absorb water from the atmosphere over time, as the fuel temp drops and I believe maybe as atmospheric pressure drops the amount of water that can be held in solution decreases, not sure about dropping atmospheric pressure but remember reading that years ago.

By adding alcohol to our aircraft fuel prior to flight, we are alcohol “rich” that is we have a mixture that can absorb more water than is present, get alcohol rich enough and fuel won’t phase separate in cold temps.

I’d follow the POH, if it said 3% then that’s what I’d add if I was concerned

I know it’s probably obvious, but there is a specific alcohol that you must use, you can’t or shouldn’t use any other.

Years ago I went on a mission if you will to find the number of aircraft crashes from aircraft burning E10 gasoline, in short I couldn’t find any, but I know for a fact that many, many aircraft are burning it.

I’m not abdicating burning it because it’s dis allowed, but it was interesting that at that time I couldn’t find any crashes attributed to it.

No, they do not separate into 2 phases.  IPA and water are completely miscible.

Posted
4 hours ago, Ibra said:

Isopropyl 1% should help with this (M20K 231 says 3% but it seems a lot, 1% is more than enough)

My J manual says “not to exceed 1%” - so presumably something less than 1% is also effective? Is a “splash” of isopropyl going to do anything at all?

image.jpeg.66151d4bcb05859eff60ac803d01ef88.jpeg

Posted
6 minutes ago, toto said:

My J manual says “not to exceed 1%” - so presumably something less than 1% is also effective? Is a “splash” of isopropyl going to do anything at all?

image.jpeg.66151d4bcb05859eff60ac803d01ef88.jpeg

I really wish there was a recommendation for what temperature to use this at?  Even in my lowly F I sometimes fly around -20c at 10,000’ in the winter.  Is that cold enough or are we left to guess?

Posted
Just now, Ragsf15e said:

I really wish there was a recommendation for what temperature to use this at?  Even in my lowly F I sometimes fly around -20c at 10,000’ in the winter.  Is that cold enough or are we left to guess?

Yeah I was hoping to have someone give a primer on alcohol additives. I’ve never put alcohol in the fuel despite flying winter cross countries over inhospitable terrain - and if there’s a good reason to add alcohol, then it is something I’ll probably start doing. 

Posted (edited)
29 minutes ago, neilpilot said:

No, they do not separate into 2 phases.  IPA and water are completely miscible.

IPA and Methanol, Ethanol  and water all are completely miscible, within limits, exceed those limits and the water drops out

Those limits are I believe temperature related.

From this website https://petroclear.com/resources/dont-be-phased.php

As noted on Chevron's Web site, while conventional gasoline can dissolve up to 150 parts per million of water at 70°F, the situation is different for gasoline oxygenated with 10% ethanol. This 90% gasoline/10% ethanol blend can dissolve up to 7,000 ppm of water at 70°F. When this blend is cooled, both the water and some of the ethanol become insoluble. Contacting the blend with more water also draws ethanol from the blend. The result, in both cases, is two layers of liquid, an upper ethanol-deficit gasoline layer and a lower ethanol-rich water layer.”

For example ever tried to dissolve sugar in ice tea? Good luck, but for some reason people North of the Mason Dixon line don’t understand that.

However for some reason O2 saturates at a lower temp in water water than cold, that’s one reason fish die in warm water, there isn’t enough O2. So things always dissolve better in warm temps apparently isn’t an absolute.

Edited by A64Pilot
Posted
12 minutes ago, Ragsf15e said:

I really wish there was a recommendation for what temperature to use this at?  Even in my lowly F I sometimes fly around -20c at 10,000’ in the winter.  Is that cold enough or are we left to guess?

I don’t think it’s necessarily just a temp, it’s a temp PLUS how much water is in saturation in your fuel, unfortunately you don’t know that amount.

If I were concerned, I’d add the alcohol, I don’t think it hurts, but I wouldn’t add it until pre flight myself. I’m suspicious of it sitting in there long term for a couple of reasons

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Posted (edited)
49 minutes ago, A64Pilot said:

IPA and Methanol, Ethanol  and water all are completely miscible, within limits, exceed those limits and the water drops out

I think for 1% proportions, they are well miscibles even at low temperatures, the only operational advantage is lowering freezing point 

For the purpose of testing fuel smaples say it has 1% of water (that is not visible). Can I test and separate that by pouring lot of ethanol (or isopropyl) in fuel sample? 

With 1% ethanol in fuel, I can test and separate that by pouring lot of water in fuel

For isopropyl, I guess it depends on so much factors, however, a small trace it it should kick fuel  freezing points to comfortable levels (assuming no visible water was was in drains) 

Edited by Ibra
Posted
2 hours ago, A64Pilot said:

and that’s in my opinion another reason to not add the alcohol until your ready to fly

Also a good argument for not fueling until ready to fly because the IPA needs to be added as the fuel is added.  Doesn't work if you just dump it in on top of the fuel.

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