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  #21  
Old 02-07-2021, 10:41 AM
woxofswa woxofswa is offline
 
Join Date: Sep 2007
Location: Mesa Arizona
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I too was all excited about compression ignition back in the kit planning stages. I remember speaking to a engine manufacturer rep at Copperstate about 2006 or so and him regaling us with tales of how they were only a "year or two away from showing a diesel that would be a bolt in replacement for an IO540." Yeah right

A little advise. Before going down any alternative path, talk to a handful of insurance brokers first. Any possible economic factors must include insurance which can be exorbitant if even available for alternative propulsion.
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  #22  
Old 02-07-2021, 11:03 AM
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D Weisgerber D Weisgerber is offline
 
Join Date: Sep 2019
Location: Ionia Michigan
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Quote:
Originally Posted by Vansconvert View Post
Auto and truck engines can run on propane. Has anybody done this with an aircraft engine?
I think propane would be problematic. The tanks would be much heavier and it is a gas under pressure which would be more dangerous. The other issue is where would you get fuel.
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  #23  
Old 02-07-2021, 11:21 AM
RVDan RVDan is offline
 
Join Date: Jun 2012
Location: Frederick, MD
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Quote:
Originally Posted by Rob_The_Builder View Post
My end goal is to not use AvGas. But equally important is to also reduce pilot work load and get a better performing engine.

Electronic ignition = no mixture adjustment
Turbocharged = less performance loss at altitude
No carburetor = no carb-icing
Jet-A = lower fuel cost and more availability
What about reliability? Would you want 3 others onboard with a powerplant and propeller drive of unknown durability?
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  #24  
Old 02-07-2021, 12:06 PM
Desert Rat Desert Rat is offline
 
Join Date: Aug 2018
Location: 50-50 Wichita KS & Scottsdale AZ
Posts: 539
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Quote:
Originally Posted by Rob_The_Builder View Post
My end goal is to not use AvGas. But equally important is to also reduce pilot work load and get a better performing engine.

Electronic ignition = no mixture adjustment
Turbocharged = less performance loss at altitude
No carburetor = no carb-icing
Jet-A = lower fuel cost and more availability
Seems to me that you can get the top 3 already with existing technology. The question is, should you?

FADEC? That's nice in a Jet or whatever, but I'll keep my mixture control, thanks. I've flown a DA42 and it's cool, but not cool enough to make me want to deal with the potential down side.

A Diamond factory pilot crashed a DA42 due to their supposedly foolproof double redundant dual Fadecs going off line right after takeoff. The reason? The battery was dead, so they started the airplane with a GPU. When the gear was retracted, the load on the not 100% recovered electrical system rocked their little computer world and that was that. The fix was to add a couple more backup batteries for I guess what would now be quadruple redundancy, which seems like an awful lot of hassle just to get rid of a red knob.

Turbo? An RV already cruises so close to redline (which is measured in TAS) that if you could keep sea level power to altitude, you would likely need structural modifications and the flight test program that should go with it in order to take advantage of those extra ponies.

No Carb? aren't we just talking about fuel injection here?

I get the reason that diesel is desirable in Europe, where 100LL is scarce/expensive, but in the US I just don't see a practical reason to move away from the tried and true Lycoming.

Best of luck to you if you go this way. and maybe I'm just set in my ways, but I thought long and hard before I pulled the trigger on a IO390 order for my RV7 just because I didn't want to add a bunch of time to my build due to having to figure out a bunch of stuff that Vans doesn't give guidance for...
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  #25  
Old 02-07-2021, 12:39 PM
12vaitor 12vaitor is offline
 
Join Date: Aug 2012
Location: Panama City, FL
Posts: 160
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I am surprised there is no discussion of a hybrid electric power plant for the RV-10. Something like the MagniX 250 might be a bit overkill at 375hp, however this is where all the technology develop dollars seem to be going. Direct drive generators on a sustainer IC motor appears to be most realistic configuration if you want any reasonable range. Rather than an expensive turbine, a turbo boosted Mazda type rotary with a direct drive generator may be the most cost effective hybrid combination. JET A is a practical for the near term with LNG/H2 coming on once the distribution facilities are in place (Mazda already has a dual fuel/H2 powered rotary).

The EU is really pushing H2 power and I expect global warming/cooling/climate change inspired (mandated) trends will force aviation powerplants to either pure electric or some form of H2 based fuel (direct combustion or fuel cell). Sadly, the EU seems to be inspiring a lot more innovation in GA than the US.
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  #26  
Old 02-07-2021, 01:11 PM
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rmartingt rmartingt is offline
 
Join Date: Nov 2006
Location: Savannah, GA
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Quote:
Originally Posted by Desert Rat View Post
A Diamond factory pilot crashed a DA42 due to their supposedly foolproof double redundant dual Fadecs going off line right after takeoff. The reason? The battery was dead, so they started the airplane with a GPU. When the gear was retracted, the load on the not 100% recovered electrical system rocked their little computer world and that was that. The fix was to add a couple more backup batteries for I guess what would now be quadruple redundancy, which seems like an awful lot of hassle just to get rid of a red knob.
Moral of the story there is to know the systems on your airplane (which goes for any airplane, but especially a homebuilt, whether you built it or not), not “this stinks because it’s not the same as traditional airplanes”. If you have an electrically-dependent engine, you don’t just jump it off and then fly away on a dead battery—just like you don’t jump start a glass cockpit airplane and then fly into IMC. I don’t even like jump-starting my car for similar reasons; no way in **** I’m doing it to my airplane. Do it right and charge the battery properly.

But, if you’re not comfortable with electronic injection/ignition/FADEC, or all-glass panels, or tailwheels, or composites, or (insert anything here), you don’t have to use them. That’s the beauty of E-AB. You can weigh the pros and cons as you see them, and build it the way you want.
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  #27  
Old 02-07-2021, 01:34 PM
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rmartingt rmartingt is offline
 
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Location: Savannah, GA
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Quote:
Originally Posted by 12vaitor View Post
Sadly, the EU seems to be inspiring a lot more innovation in GA than the US.
From my experience talking to FAA and EASA regulators on the ASTM committee (back when they were working on rewriting Part 23) I found the Europeans far more open to new ideas, and far more willing to discuss changing the regs when they didn’t make sense, even though they were more strict and more restrictive in general.

The FAA, by contrast, is less controlling in many ways, but once they make a decision (on a regulation, interpretation, or anything else) it practically takes an act of God to get them to change their minds. Something completely new and different, they’ll consider, but if it’s even remotely close to anything that currently exists they will try their hardest to view it through that lens. Two quotes from FAA types on the committee:

“Well, we agree that requirement doesn’t make sense. But, we don’t know why they wrote it that way, so we aren’t going to change it”.

“There won’t be any changes to that number. We’ve heard it was on the third tablet that Moses dropped coming down the mountain”.

I think that’s why light (certified) GA development mostly seems to be coming from Europe—the regulators are more open to considering things outside the box, and they are more willing to scale down requirements that were originally developed for larger aircraft.

To circle back, one of the reasons we don’t see much in the way of FADEC/EEC/EFI on light aircraft is that the regs for those were originally written back when large passenger-carrying turbine-powered aircraft were the only feasible application. The regs were written with those in mind. Now, modern technology has made it feasible for light aircraft, but the rules haven’t changed. They’re still written to the needs of commercial engines, which are arguably overkill for a light aircraft—and definitely much more demanding than the standards for the carbs and mags so many still fly behind today.
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  #28  
Old 02-07-2021, 02:19 PM
sailvi767 sailvi767 is offline
 
Join Date: Sep 2010
Location: Charlotte NC
Posts: 1,287
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Quote:
Originally Posted by woxofswa View Post
I too was all excited about compression ignition back in the kit planning stages. I remember speaking to a engine manufacturer rep at Copperstate about 2006 or so and him regaling us with tales of how they were only a "year or two away from showing a diesel that would be a bolt in replacement for an IO540." Yeah right

A little advise. Before going down any alternative path, talk to a handful of insurance brokers first. Any possible economic factors must include insurance which can be exorbitant if even available for alternative propulsion.
Insurance is a big issue. The Lance Air 4P turbine is probably the most common conversion out there with a decent number flying. A friend has one currently. He does factory yearly recurrent, 20,000 plus hours, ATP, extensive GA experience and no prior claims ect. Insurance is 17,000 a year on 350,000 in hull value. Liability only is 6000.
Many 4PTurbine buyers with lessor quals can’t get any insurance.
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  #29  
Old 02-07-2021, 03:32 PM
Freemasm Freemasm is offline
 
Join Date: Nov 2017
Location: Orlando
Posts: 322
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Quote:
Originally Posted by 12vaitor View Post

The EU is really pushing H2 power and I expect global warming/cooling/climate change inspired (mandated) trends will force aviation powerplants to either pure electric or some form of H2 based fuel (direct combustion or fuel cell). Sadly, the EU seems to be inspiring a lot more innovation in GA than the US.

If someone believes in the economics or the “greenness” of Hydrogen, you should
Invest your retirement savings In it. I did energy balances for a living, H2 makes zero environmental or economic sense.

Last edited by Freemasm : 02-07-2021 at 03:36 PM.
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  #30  
Old 02-07-2021, 03:51 PM
Freemasm Freemasm is offline
 
Join Date: Nov 2017
Location: Orlando
Posts: 322
Default Caught myself, sort of.

I basically was one of those holes who make statements without any substantiation. So, here is a copy of a previous post of mine with some facts and stats:

The Majority of Economics of Renewable Energy is a lie. The costs associated with back-up power and "spinning reserve" are not included. Renewables also aren't nearly as green as they portray themselves. Gas turbines cycling load, making pollution while operating under no load conditions, giving up 50% of their relative efficiencies operating in simple cycle mode, all to prop up wind and solar generation's unpredictable output. There are a lot of hidden costs and environmental impacts. Add on the fact that their levelized costs are very high compared to other forms of generation (Hydro is the exception), it makes even less sense.

Every time you convert energy there is loss. For the H2 cycle: Chemical to mechanical, to electrical, to chemical, to mechanical, to electrical (first conversion drops off if using renewable source) Multiply numbers all less than 1, the product gets very small, very fast. It is a tremendous waste of resources. A quick example: to fuel a single 260MW gas turbine with hydrogen requires 1033MW (per unit time). It would also consume about 200,000 l/h of water. So, make more directly related pollution for less usable power.

So, use "green" H2 made from renewable energy. You still gave up a lot of energy. It would only take over 400 wind turbines of the most common sized frame. Those would need about 750 acres of land. BTW their capacity factor is only about 1/3 so triple the aforementioned quantities for a true average needs. Solar is worse with only about 16-18% capacity factor.

Anyone mention that there's no H2 infrastructure? Want to tanker it? The amount of energy required to liquify it hasn't been considered. You're now probably pretty close to zero net efficiency. Now if you want to turn H2 into electricity because it's a by-product of your refinery process, please do (Propane used to be a flare gas, BTW). I have a lot of respect for people who can make money off of their waste.

We can be much smarter on energy policy and utilization but common sense needs to prevail. There's a whole lot more to this but only so much time write. I'll state again, if someone truly believes in the economics of H2, don't debate it here. Go invest your retirement savings in it. Fortunes are made in such but those people are typically utilizing other people's money and riding the wave of excitement and current political winds. This is not the first time the "New Hydrogen Economy" has been touted. Physics hasn't changed since then. Enjoy.

Last edited by Freemasm : 02-07-2021 at 04:11 PM.
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