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Car Engines vs. Aircraft Piston Engines


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I know of at least one modern car engine being used in aviation. The Hummingbird Helicopter uses the Chevrolet LS7, it's detuned to turn at 3,000 RPM makes 300 HP and it's still fuel injected/water cooled. That Heli is an experimental based off of an S-52, the LS7 engine and its components add $50k to the price so it's not cheap.

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  • 2 weeks later...

So, I still think that if someone would design an aircraft engine for a small helicopter from scratch today, it wouldn't look anything like, say, a Lycoming 360. That must mean it's really mostly cost of certification and development holding things back, like 500 and GP said.

 

 

 

 

Irrelevant. It doesn't matter what's designed, if there's not a market big enough to make a return on the investment of design, development, certification, tooling, and production, and to cover the cost of liability associated with putting the engine on the market.

 

If you don't understand the effect that liability has on the aviation market, especially general aviation, look at the mishap that helicopter pilot Craig Hoskins had several years ago in his Pitts at Salt Lake City, during an airshow. He made an error in judgement, destroyed his aircraft, and blamed it on his engine. His resulting law suit against the engine manufacturer resulted in a drastic price increase for that engine world wide.

 

Some years ago, a man flying a late 1940's super cub from the wrong seat, with illegal camera equipment installed in his pilot seat, took off from a closed and placarded runway after being banned from the airport, and crashed into a van parked on the runway. He died. His estate sued, and the resulting law suit was the largest jury award in general aviation history. It put piper aircraft out of business.

 

Over 60% of the cost of most light aircraft today is strictly to cover insurance and related liability expenses. That's just liability after manufacture.

 

The cost to certify a new airframe or power plant is staggering, even with some of the tort reform that took place years ago. The manufacturer needs to be able to expect a significant enough return on the investment to justify the cost of certification, and be willing to handle the resulting liability. Putting an engine in an aircraft is not at all the same as putting it in a car, which can simply pull over following a failure.

 

Aircraft engines are subject to significant stresses and limitations; RPM limitations due to the work performed (moving rotors, propellers, etc), as well as thermal stresses. They also face weight limitations, which restrict the metals which may be used to construct the engines.

 

Even manufacturers for parts on engines have faced big law suits and challenges. The big ECI cylinder debacle not too long ago resulted in very large law suits and settlements. Putting oil in engines cost Phillips a large fortune in law suits resulting from the original X/C oil.

 

Many shops won't sell parts or supplies if they know it goes in an aircraft. Take the generator from your airplane or helicopter to a local auto electric shop for an overhaul, tell them it's from an aircraft, and watch them refuse it so fast you'll wonder if you ever asked the question. Tell them it's from a tractor or a car, and they'll overhaul it in a heartbeat. It may be the same generator (often is), but knowing it's from an aircraft changes everything. It's part of the reason that many automotive parts that are used in aircraft (Ford voltage regulators, for example, or Chevy garlock seals) carry the same part number, are the same part, but have a much higher price when sold for aircraft.

 

There have been a number of changes and improvements to products over the years, and the "antiquated" aircraft engines that you think you see aren't nearly so antiquated as you think. They are also better suited to the application than you think.

 

There have been a number of automotive conversions for use in experimental aircraft; some have been quite successful, such as the EA22 and EA25 Suburu engines used in some gyroplanes and other homebuilts. Others have had a lot of problems, such as the V8 conversions used in the Thunder Mustangs...lots of failures and crashes. Engines made for cars don't necessarily make good engines for airplanes. Why massive crankshafts? The loads and harmonics transmitted to aircraft engines are not the same as what's imposed on engines in cars. Even the oils are different, for valid, well established reasons.

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  • 2 years later...

Wow I have never heard so many people in one place as I hear in the aircraft industry say it can't be done and I do understand why liability ok there is a huge amount of liability in building an air craft no doubt about that but I also believe it can and should be done at least in the experimental sector but the people that have the financial means do not want to redesign the wheel I get it I see helicopters used to crop dust wow those things can be beat up but if they are taken care of then great fly it all day long and uncomfortable omg leaking people dont have automobiles that look bad leak water in the rain and are uncomfortable to drive but they take care of the running gear I can tell you that the ls engine is a stable platform to build a helicopter they do not run on the red line but they dont need too there power band is wide but can be narrowed pretty small they have adaptive learning so they can fly at any altitude under 10,000 feet ok let's say I build an engine to keep its power band 2000 to 3500 rpm that is just about right at that rpm that engine is capable of producing 250 to 300 hp naturally aspirated the aluminium versions weigh approx 400 lbs as far as reliability I have one in my truck I have 350,000 miles the original engine it does not smoke or knock the only reason it has ever shut completely down is the fuel pump quit that in a helicopter should be redundant anyway it gets 18 mpg with an average mph of 35mph do the math on that that is averaging 2400 rpm and let's say consertivly 180 hp 225tq I have not seen many engines do that consistently as far as air cooled and water cooled go blow that smoke up someone else's but water cooled is hands down better in my opinion it can be controlled with ease make no mistake about it certified engines will not change in the aviation industry because no one is fighting to change them everyone has the same mindset I just can't imagine driving around a car or bike made in the last 10 years with a carb why would I ever pay 200k for a aircraft with carbs air cooled engine hard seats leaking doors and 60/70s technology that is ludicrous

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How are you going to change them? Regulation to force manufacturers to a higher standard? That would completely destroy the industry as they would never be able to recuperate the R&D costs.

 

The only way I could see big leaps being made is to fully fund the research and development with public money.

Edited by SBuzzkill
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How are you going to change them? Regulation to force manufacturers to a higher standard? That would completely destroy the industry as they would never be able to recuperate the R&D costs.

 

The only way I could see big leaps being made is to fully fund the research and development with public money.

 

Well dah US guberment would surely fund it if it had a means to an end for the military.

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Wow I have never heard so many people in one place as I hear in the aircraft industry say it can't be done and I do understand why liability ok there is a huge amount of liability in building an air craft no doubt about that but I also believe it can and should be done at least in the experimental sector but the people that have the financial means do not want to redesign the wheel I get it I see helicopters used to crop dust wow those things can be beat up but if they are taken care of then great fly it all day long and uncomfortable omg leaking people dont have automobiles that look bad leak water in the rain and are uncomfortable to drive but they take care of the running gear I can tell you that the ls engine is a stable platform to build a helicopter they do not run on the red line but they dont need too there power band is wide but can be narrowed pretty small they have adaptive learning so they can fly at any altitude under 10,000 feet ok let's say I build an engine to keep its power band 2000 to 3500 rpm that is just about right at that rpm that engine is capable of producing 250 to 300 hp naturally aspirated the aluminium versions weigh approx 400 lbs as far as reliability I have one in my truck I have 350,000 miles the original engine it does not smoke or knock the only reason it has ever shut completely down is the fuel pump quit that in a helicopter should be redundant anyway it gets 18 mpg with an average mph of 35mph do the math on that that is averaging 2400 rpm and let's say consertivly 180 hp 225tq I have not seen many engines do that consistently as far as air cooled and water cooled go blow that smoke up someone else's but water cooled is hands down better in my opinion it can be controlled with ease make no mistake about it certified engines will not change in the aviation industry because no one is fighting to change them everyone has the same mindset I just can't imagine driving around a car or bike made in the last 10 years with a carb why would I ever pay 200k for a aircraft with carbs air cooled engine hard seats leaking doors and 60/70s technology that is ludicrous

Punctuation, paragraphs, please

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