ls1 in homebuilt aircraft!!!
06-13-2007, 01:10 PM
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ls1 in homebuilt aircraft!!! My dad is building an airplane to make trips to and from Alaska in and he was considering using an lsx motor. Specially built plane motors are outrageously expensive(30-40k) and do not make near as much horsepower or operate as efficiently as a ls1. I was curious if anyone has ever done this or seen it done, this is not a bs story so please dont make fun of me. BTW, it will be a 3 seater 2000lb payload plane roughly. Thanks for any input guys.
06-13-2007, 01:39 PM
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I've seen one posted on here, was a single turbo LSx motor in a custom carbon fiber airframe. Not sure of any of the other details.
I've also seen Subaru boxer 4's converted for experimental use.
One of the things that you'll need to think long and hard about: Engines in planes & boats are subject to completely different loading than car engines.
A car engine can make 400hp and last for 1,000's of miles because most of the time its making very little horsepower (cruising at 75mph in a camaro probably requires under 25hp) and be operating at fairly low rpm (2000 or less).
An airplane or boat engine can expect to run alot harder. You'll be asking for a much larger output (maybe 200 or 250 hp) at correspondingly higher rpm (3000 rpm plus). You may even ask for peak power output (throttle to the firewall) for an extended period of time (especially in a boat application, maybe not an airplane). This is extreme duty in every sense of the phrase. Parts wear out / fail catastrophically when subject to this kind of use. Which is why alot of the airplane engines have extensive inspection requirements.
In short, a car engine in a plane application can be made to work. But you'll need to build the engine from the ground up exclusively for this application. And you'll want to do all the inspection (like magnafluxing every square inch of each rod, crank, etc) to verify that the motor won't come apart before you take it apart. After all, you can't just pull over in an airplane....
'JustDreamin'
Originally Posted by bczee
RX7 engines have also been used.
One of the things that you'll need to think long and hard about: Engines in planes & boats are subject to completely different loading than car engines.
A car engine can make 400hp and last for 1,000's of miles because most of the time its making very little horsepower (cruising at 75mph in a camaro probably requires under 25hp) and be operating at fairly low rpm (2000 or less).
An airplane or boat engine can expect to run alot harder. You'll be asking for a much larger output (maybe 200 or 250 hp) at correspondingly higher rpm (3000 rpm plus). You may even ask for peak power output (throttle to the firewall) for an extended period of time (especially in a boat application, maybe not an airplane). This is extreme duty in every sense of the phrase. Parts wear out / fail catastrophically when subject to this kind of use. Which is why alot of the airplane engines have extensive inspection requirements.
In short, a car engine in a plane application can be made to work. But you'll need to build the engine from the ground up exclusively for this application. And you'll want to do all the inspection (like magnafluxing every square inch of each rod, crank, etc) to verify that the motor won't come apart before you take it apart. After all, you can't just pull over in an airplane....
'JustDreamin'
06-13-2007, 01:56 PM
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I recall my mom's neighbor built an experimental with the boxer Subaru engine.
Like Justdreamin' stated, aircraft engines are designed to operate under very different stresses than automobile engines are. Higher rpm, constant load.
Like Justdreamin' stated, aircraft engines are designed to operate under very different stresses than automobile engines are. Higher rpm, constant load.
06-13-2007, 02:14 PM
#6
Also is a plus to use postive pressure intake system.. RX7 twin Turbo Charged ! I was at a RX7 shop and they were taking order for custom built RX7 for aircrafts a few years ago.
Some of them have used some sort of Gear reduction system or gear box to help out in keeping the engine in the RPM Power range.
But I think you will find that there is a great use in Car engine in aircraft. But in a smaller circle.
Some of them have used some sort of Gear reduction system or gear box to help out in keeping the engine in the RPM Power range.
But I think you will find that there is a great use in Car engine in aircraft. But in a smaller circle.
06-13-2007, 02:27 PM
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Actually, most air-cooled aircraft engines are low rpm. Like 2000-2400 rpm cruise, 2650-2850 at max takeoff power. Most are direct drive & if you spin a medium to large sized prop faster, the tips go supersonic & lose efficiency and get VERY loud. V8s generally would need a prop speed reduction unit to get the rpm back down into an efficient range.
A few aircraft V8 pages:
http://www.vestav8.com/FAQ.htm\
David Algie's CF homebuilt in progress:
http://members.iquest.net/~aca/index.htm
http://groups.yahoo.com/group/algiecompositeaircraft/
Assuming this is a kit aircraft, unless the manufacturer has a V8 firewall forward kit, by the time you re-engineer the mount, add the PSRU, and add all the plumbing, I'd guess you'd be close to the 30-40K range anyway.
BTW, what 3 seater homebuilt has a useful load of 2000 pounds? Or are you just planning on leaving out a couple seats of a Compair 7 or something similar?
A few aircraft V8 pages:
http://www.vestav8.com/FAQ.htm\
David Algie's CF homebuilt in progress:
http://members.iquest.net/~aca/index.htm
http://groups.yahoo.com/group/algiecompositeaircraft/
Assuming this is a kit aircraft, unless the manufacturer has a V8 firewall forward kit, by the time you re-engineer the mount, add the PSRU, and add all the plumbing, I'd guess you'd be close to the 30-40K range anyway.
BTW, what 3 seater homebuilt has a useful load of 2000 pounds? Or are you just planning on leaving out a couple seats of a Compair 7 or something similar?
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06-13-2007, 07:05 PM
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Thanks guys, i didnt think i would get this many responses. My dad is really leaning toward a ls7 for reliability and strength. When that crate ls7 shows up in the, its gonna be hard to not take it and put it in my 3rd gen.lol
06-13-2007, 07:30 PM
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there are a few more issues you need to consider. alaska is a colder climate and get's very cold when your a few thousand feet up. water cooled engines don't work well at all in thinner air and cold climate.that is y aircooled is very populor.
the gear reduction would be mandatory as a prop can not efficently spin beyond 3500 rpm at sea level. higher elavation is even harder to be efficent.
also the valve train needs to be seriously addressed. you'll need a small cam without extreme lift ramps to prevent spring failure which is going to be one of your bigger problem's. dual springs and a rev kit(road race type set up)will go a long way in helping here. also going with very light valve train set up in general. valves rockers push rods
as for being a good milage motor your not comparing apples to apples. a prop drive is far more inefficent then tires on a road. you'll lose a good amout here. also your ls1 motor to make power will be spinning constanly at 5k and above which is were these motor's suck fuel. I've personly have gotten 6-8 mpg with a t-56 on the street driving very aggresivly.
A gear reduced v8 even a ls1 is going to be heavy to compared to a similiar aircraft engine.
I'm not tring to say it won't work or isn't even a good idea as most problems with the set up can be overcome however it is going to be easy or cheap to do so which is what yuor looking at doing.think about it hard and do a bite more research on this subject before you start spending money. there are sevreal good light aircraft building books on the shelves at barnes and noble that can spell out just about every factor to doing a custom built plan. I personaly have done a lot of research myself in this are for another project I've considered but cam to the conclusion that the cost, work, and risk would not pay off for me personaly.
I didn't even mention all the custom parts your going to have to source such as a proper prop, engine mount's etc.
the gear reduction would be mandatory as a prop can not efficently spin beyond 3500 rpm at sea level. higher elavation is even harder to be efficent.
also the valve train needs to be seriously addressed. you'll need a small cam without extreme lift ramps to prevent spring failure which is going to be one of your bigger problem's. dual springs and a rev kit(road race type set up)will go a long way in helping here. also going with very light valve train set up in general. valves rockers push rods
as for being a good milage motor your not comparing apples to apples. a prop drive is far more inefficent then tires on a road. you'll lose a good amout here. also your ls1 motor to make power will be spinning constanly at 5k and above which is were these motor's suck fuel. I've personly have gotten 6-8 mpg with a t-56 on the street driving very aggresivly.
A gear reduced v8 even a ls1 is going to be heavy to compared to a similiar aircraft engine.
I'm not tring to say it won't work or isn't even a good idea as most problems with the set up can be overcome however it is going to be easy or cheap to do so which is what yuor looking at doing.think about it hard and do a bite more research on this subject before you start spending money. there are sevreal good light aircraft building books on the shelves at barnes and noble that can spell out just about every factor to doing a custom built plan. I personaly have done a lot of research myself in this are for another project I've considered but cam to the conclusion that the cost, work, and risk would not pay off for me personaly.
I didn't even mention all the custom parts your going to have to source such as a proper prop, engine mount's etc.
06-13-2007, 09:21 PM
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I have seen an LS1 in a Lancair IVP. It looked nice but he had major cooling and tunning problems, altitude related I am guessing less air up high.
He later spent the money on a proven Continental TSIO-550 with a dry weight of 442.10 lbs. without accessories. The average
weight of the engine with installed accessories is approximately 565 lbs.
Rated Maximum Continuous Operation 310 BHP @ 2600 RPM all the time!
I am an A&P and a pilot. I wouldn't my life or family on the line for a car engine that flies!
I think some of the others above listed all the points as to why it won't work well. Namely running the car motor at higher RPM to get the same HP as a A/C engine and mainly the reduction of Time Before Overhaul of the LSX engine vs certified engine.
He later spent the money on a proven Continental TSIO-550 with a dry weight of 442.10 lbs. without accessories. The average
weight of the engine with installed accessories is approximately 565 lbs.
Rated Maximum Continuous Operation 310 BHP @ 2600 RPM all the time!
I am an A&P and a pilot. I wouldn't my life or family on the line for a car engine that flies!
I think some of the others above listed all the points as to why it won't work well. Namely running the car motor at higher RPM to get the same HP as a A/C engine and mainly the reduction of Time Before Overhaul of the LSX engine vs certified engine.
06-13-2007, 09:55 PM
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LS1MCSS..
The Nexaer LS1 uses a lightweight aircraft engine in the 80 to 120 hp range, not a GM LS1. There's no way you'd be able to put an LS1 engine in a plane manufactured to Light Sport Aircraft specs. Way too heavy...
The Nexaer LS1 uses a lightweight aircraft engine in the 80 to 120 hp range, not a GM LS1. There's no way you'd be able to put an LS1 engine in a plane manufactured to Light Sport Aircraft specs. Way too heavy...
