LS1 aircraft engine
Right now I'm considering whether to use a LS1 based engine or a stroked 350 for the engine in a homebuilt P51 scale replica I'm building. What I want is to get 320 or better horsepower at no more than 4800 rpm and be able to cruise at 3500 to 3800 with 220 or so. I need a fairly flat torque curve from 2000 up. The engine will be geared down using a PSRU (prop shaft reduction unit) of 2 to 1 or higher reduction ratio.
Right now it appears the LS1 setup is a pretty good solution to achieve all that at a lighter weight than an aluminum head cast iron small block. With the introduction of lower priced forged crank/piston/rod assemblies the cost is dropping pretty fast.
One of the questions if have is about the adaptor for using a more or less conventional distributor on the LS1. I can't find anything specific about it or when it's to be introduced. Does anyone know about it? I don't plan to use a distributor, since the crank trigger setup seems to work well and is already there, but some have used the distributor drive to run a prop governor for aircraft use on small and large blocks. If I could do that it would save a lot of heartburn trying to set up a drive.
Another question is what is available to rearrange the belt/pully system to eliminate the a/c compressor?
I'll be using short (no more than 12 inches) stacks or possibly a log type manifold with 6 stacks coming out per side. No O2 sensors. I realize I'll be giving up some power, but since the original V12 in the P51 had stacks, I need to do it to keep the appearance and sound. I also need to dump the heat overboard, since the cowling is tight. Hot exhaust headers could be a bad thing. Any estimates of how much power loss? How will the computer handle this?
Speaking of computers, to me it appears my setup will allow elimination of lots of wire and functions, since I only need FI and ignition control (I'd like to keep the knock protection, since with this application there's no way you would hear detonation). Am I correct?
What's the weight of a LS1 with accesories (no manifolds or A/C)? I'm assuming it's quite a bit (50 or more) less than an iron block/aluminum head small block.
Thanks for any suggestions.
There are no distributor provisions on a LS1.
You have to use crank/cam triggers in motor.
A good option fo you may be the edelbrock carb manifold for LS1's that comes w/ a computer to run the ignition.
That would eliminate alot of your computer problems.
The A/C compressor would be no problem to remove it has it's own dedicated belt.
The exhaust your invisioning sounds wild at the least.
Another reason to run the carb'd manifold.
Well good luck with you endeavor.
Some of the drag racers have gone with a belt-drive distributor system, that mounts on the front of the engine. Big money there though, as it is custom.
For one is how much load the prop adds which eats up the flywheel HP due to drivetrain loss ( how prop is driven by flywheel)
This setup sucked up around 200 FWHP loss and as the prop angle changed even more HP was eaten up as load increased.
Also the higher the plane flys causes air/fuel issues so they had to go with a turbo where there was boost all the time.
This added even more HP loss, esp at lower RPMs.
Due to the loss even when engine (with added load/loss of prop) started,
totally confused the PCM as to what mode engine was in and what calibration was needed to even start the engine plus use a higher RPM to maintain the load of prop duriing idle.
They also had to add an external oil pump, now more overhead loss and then they needed more voltage/amps and had to go with two generators and now even more load and HP needed for engine to handle all that load loss.
That lead then to much more fuel flow required and in the end with the flywheel HP being over 600 only less then 400 HP was measured at prop so I do not think a fairly stock LS1 would meet your goals and in any case requires a lot of time testing and tuning the PCM for this configuration.
For one is how much load the prop adds which eats up the flywheel HP due to drivetrain loss ( how prop is driven by flywheel)
This setup sucked up around 200 FWHP loss and as the prop angle changed even more HP was eaten up as load increased.<quote>
I'm not sure what you mean by the prop angle changing eating up hp. When the prop blade angle changes, it's just like changing gears in a transmission...the greater the pitch the more power it takes to turn it and the more power used to propel the airplane. Most Morse chain drives (a common reduction drive) use 3% to 5% of the flywheel horsepower; quite a bit less than the transmission/rear end in a car.
<quote>Also the higher the plane flys causes air/fuel issues so they had to go with a turbo where there was boost all the time. <quote>
That's true only at extremely high altitudes. Cars run fine to the top of Pike's Peak- 14,000 feet. The PCMs handle that fine. Turbo/super charging isn't necessary at light plane altitudes.
<quote>This added even more HP loss, esp at lower RPMs.
Due to the loss even when engine (with added load/loss of prop) started,
totally confused the PCM as to what mode engine was in and what calibration was needed to even start the engine plus use a higher RPM to maintain the load of prop duriing idle.<quote>
This may require a workaround. The idle RPM will need to be around 1000 rpm anyway. Unless on the ground, the rpm will never be less than 3500 or so anyway. The propeller changes pitch to maintain whatever it's set for unless the airspeed is very low (landing) and the throttle is closed. Therefore, low rpm power really isn't an issue.
<quote>They also had to add an external oil pump, now more overhead loss and then they needed more voltage/amps and had to go with two generators and now even more load and HP needed for engine to handle all that load loss. <quote>
Again, I'm not sure why this would be required. The standard oil pump should be sufficient and a light airplane requires no more electrical power than a car. This must have been a pretty large aircraft.
<quote>That lead then to much more fuel flow required and in the end with the flywheel HP being over 600 only less then 400 HP was measured at prop so I do not think a fairly stock LS1 would meet your goals and in any case requires a lot of time testing and tuning the PCM for this configuration.
Thanks.
Last edited by org; Dec 27, 2003 at 07:36 PM. Reason: spelling
Trending Topics
There are no distributor provisions on a LS1.
You have to use crank/cam triggers in motor.
A good option fo you may be the edelbrock carb manifold for LS1's that comes w/ a computer to run the ignition.
That would eliminate alot of your computer problems.
The A/C compressor would be no problem to remove it has it's own dedicated belt.
The exhaust your invisioning sounds wild at the least.
Another reason to run the carb'd manifold.
Well good luck with you endeavor.
The Best V8 Stories One Small Block at Time
Some of the drag racers have gone with a belt-drive distributor system, that mounts on the front of the engine. Big money there though, as it is custom.
Last edited by org; Dec 27, 2003 at 09:55 PM. Reason: correction
How much is that P-51 going to weigh and what scale will it be?
How much is that P-51 going to weigh and what scale will it be?

Last edited by org; Dec 28, 2003 at 12:32 PM. Reason: url
CamaroSS, check out the previous posts. It's not full scale and weighs about 1/4 of the original. This gives a power to weight ratio (loaded) of 7lbs per hp. The real thing has about ...7lbs per hp. This doesn't mean the replica will be as fast, but it will probably outclimb the real thing at least at low altitudes. Cruise should be in the 210 to 220 range at 65% power. This isn't something I'm pulling out of the air, but reflects similar scale Mustangs already flying with similar power. This isn't new ground, except for using the LS1 instead of a small block. Several .66/.7/.75 scale fighters (P51, Spitfire, FW 190, etc.) are flying and those with even 200 horsepower perform pretty well. Those with 300+ perform very well, keeping in mind that these aren't really fighters; they look like them, but they're still light aircraft generally performing at the upper edge of light airplane performance or a little better. They perform well, are aerobatic, and fun to fly (besides turning heads on the airport.) If you want an airplane to perform speed wise like a fighter, it has to be built like one, will guzzle fuel like one, and
will cost a fortune to maintain like one (some are becoming impossible to maintain at any price). Last edited by org; Dec 28, 2003 at 02:33 PM. Reason: spelling
Tuning the PCM is.
Their object was to be able to fly at around 30,000 feet (around 220 MPH) and around 350 MPH at lower heights.
They had a COG on flywheel to some belt driven system with auto gyro system they designed.
This was a prototype that had two props, one for taking off and landing like a copter and then other prop was on back side to have it fly like a plane.
It was fairly small, only pilot and I could fit in it.
Consider the engine computer (PCM) uses adaptive stratagy, it assumes as an example that when engine is at idle the MAP is about 30 KPA.
The PCM then sets air/fuel and timing for that condition.
Now you add the cost of the props and how it connects to the flywheel and that has changed the engine load profile, thus during start or idle the MAP might be 80 KPA, so PCM does not think engine is at idle but rather at Wide Open Throttle.
This means the whole PCM calibration had to be a one of a kind and was tricky to get engine to start with the load of props and how that caused the whole lookup tables in PCM to be hand tuned.
In this case engine had to idle no less then around 1400 RPMs for both props had to spin all the time.
Due to the turbo and the increased heat in engine bay they needed more cooling, including oil cooling of turbo thus the need for external oil cooler esp with an alumimum engine.
Not sure why they needed 2 generators,
maybe for safety reasons or amount of current load but I do know they could adjust the voltage as in the beginning they did not have enough voltage to the PCM and had to set adjustments to raise voltage to PCM power circuits.
Depending on the angle they set the props the more load and thus change of what the engine vaccum was so even sitting at idle as prop angle changed required different PCM calibration demands.
In any case as mentioned where HP a flywheel was 600, they measured only about 400 at the prop during idle so clearly in this case a stock LS1 would not even get them off the ground and before I tuned the PCM with throttle wide open engine could only get to about 3500 RPMs so the load of props were really eating up the HP.
Thanks.
Tuning the PCM is.
Their object was to be able to fly at around 30,000 feet (around 220 MPH) and around 350 MPH at lower heights.
They had a COG on flywheel to some belt driven system with auto gyro system they designed.
This was a prototype that had two props, one for taking off and landing like a copter and then other prop was on back side to have it fly like a plane.
It was fairly small, only pilot and I could fit in it.
Consider the engine computer (PCM) uses adaptive stratagy, it assumes as an example that when engine is at idle the MAP is about 30 KPA.
The PCM then sets air/fuel and timing for that condition.
Now you add the cost of the props and how it connects to the flywheel and that has changed the engine load profile, thus during start or idle the MAP might be 80 KPA, so PCM does not think engine is at idle but rather at Wide Open Throttle.
This means the whole PCM calibration had to be a one of a kind and was tricky to get engine to start with the load of props and how that caused the whole lookup tables in PCM to be hand tuned.
In this case engine had to idle no less then around 1400 RPMs for both props had to spin all the time.
Due to the turbo and the increased heat in engine bay they needed more cooling, including oil cooling of turbo thus the need for external oil cooler esp with an alumimum engine.
Not sure why they needed 2 generators,
maybe for safety reasons or amount of current load but I do know they could adjust the voltage as in the beginning they did not have enough voltage to the PCM and had to set adjustments to raise voltage to PCM power circuits.
Depending on the angle they set the props the more load and thus change of what the engine vaccum was so even sitting at idle as prop angle changed required different PCM calibration demands.
In any case as mentioned where HP a flywheel was 600, they measured only about 400 at the prop during idle so clearly in this case a stock LS1 would not even get them off the ground and before I tuned the PCM with throttle wide open engine could only get to about 3500 RPMs so the load of props were really eating up the HP.
My application will turn a propeller through a chain drive 2 to 1 reduction, so it won't have all the parasitic stuff they had. The altitudes I plan to operate at won't exceed 17,000 feet, so I won't need a turbo. I'm not sure how much torque is needed to turn the prop at idle (500 prop rpm/1000 engine) but it won't be much, since the prop will be pretty flat at idle. Several people are running small and big block chevy engines with similar setups, and one guy is flying a couple of seaplanes with a stock LS1 and LS6. I'm not sure how he set up the PCMs, but he' flown several hundred hours with no problems. I have a different speed range and will need a different reduction setup since his is a pusher, but that shouldn't make any difference to the computer.
Thanks again for the clarification; sounds like the config you saw was completely different than mine.
George builds LS1s for his Prowler Aviation - Jaguar kitplanes (I have one in my garage at the moment) and he's currently grinding a new custom stroker crank for it as I'm currently shopping around for LS-1 parts for my Jaguar! The Jaguar used to use a Rodeck block, but the LS1 is a better choice now. It is an oversized bore and stroked 383 LS1 with stock cam, dual mass flywheel from a 87-92 Corvette, and a custom stroker crank with splines ground into the 1.5" pulley shaft for the Gear Redux drive (2:1). Custom rear accessory drive driven off of the flywheel gear to include dual distributors going into single plugs - NO computer. All accessories are on the rear acc-case, Alternator (crank speed), prop governor, oil/coolant/fuel pumps, etc...etc...etc...! Again - NO computer, dual distributors, and uses Airflow Performance Fuel injection. The Jaguar uses two air conditioning evaporators for coolant radiators, one under each wing just like the Supermarine Spitfires had - you could use the same setup in your under-fuse scoop!
George has been using GM aluminum block engines in aeroplanes since the late 70s. Look him up in white pages of Yahoo.com and tell him John from Yuba City told you to call him re: LS1 for your kitplane. George used to manufacture the Jaguars, but retired and has gotten out of the kitplane manufac end, but still builds engines for them. Be advised, the engine with gear redux and accessory drive built for 350+HP does come up to around $25K once it's ready to plug & play! His Jaguar also uses the Vortech Supercharger.
Cheers! Happy New Year!
Cabi~
Right now I'm considering whether to use a LS1 based engine or a stroked 350 for the engine in a homebuilt P51 scale replica I'm building. What I want is to get 320 or better horsepower at no more than 4800 rpm and be able to cruise at 3500 to 3800 with 220 or so. I need a fairly flat torque curve from 2000 up. The engine will be geared down using a PSRU (prop shaft reduction unit) of 2 to 1 or higher reduction ratio.
Right now it appears the LS1 setup is a pretty good solution to achieve all that at a lighter weight than an aluminum head cast iron small block. With the introduction of lower priced forged crank/piston/rod assemblies the cost is dropping pretty fast.
One of the questions if have is about the adaptor for using a more or less conventional distributor on the LS1. I can't find anything specific about it or when it's to be introduced. Does anyone know about it? I don't plan to use a distributor, since the crank trigger setup seems to work well and is already there, but some have used the distributor drive to run a prop governor for aircraft use on small and large blocks. If I could do that it would save a lot of heartburn trying to set up a drive.
Another question is what is available to rearrange the belt/pully system to eliminate the a/c compressor?
I'll be using short (no more than 12 inches) stacks or possibly a log type manifold with 6 stacks coming out per side. No O2 sensors. I realize I'll be giving up some power, but since the original V12 in the P51 had stacks, I need to do it to keep the appearance and sound. I also need to dump the heat overboard, since the cowling is tight. Hot exhaust headers could be a bad thing. Any estimates of how much power loss? How will the computer handle this?
Speaking of computers, to me it appears my setup will allow elimination of lots of wire and functions, since I only need FI and ignition control (I'd like to keep the knock protection, since with this application there's no way you would hear detonation). Am I correct?
What's the weight of a LS1 with accesories (no manifolds or A/C)? I'm assuming it's quite a bit (50 or more) less than an iron block/aluminum head small block.
Thanks for any suggestions.
George builds LS1s for his Prowler Aviation - Jaguar kitplanes (I have one in my garage at the moment) and he's currently grinding a new custom stroker crank for it as I'm currently shopping around for LS-1 parts for my Jaguar! The Jaguar used to use a Rodeck block, but the LS1 is a better choice now. It is an oversized bore and stroked 383 LS1 with stock cam, dual mass flywheel from a 87-92 Corvette, and a custom stroker crank with splines ground into the 1.5" pulley shaft for the Gear Redux drive (2:1). Custom rear accessory drive driven off of the flywheel gear to include dual distributors going into single plugs - NO computer. All accessories are on the rear acc-case, Alternator (crank speed), prop governor, oil/coolant/fuel pumps, etc...etc...etc...! Again - NO computer, dual distributors, and uses Airflow Performance Fuel injection. The Jaguar uses two air conditioning evaporators for coolant radiators, one under each wing just like the Supermarine Spitfires had - you could use the same setup in your under-fuse scoop!
George has been using GM aluminum block engines in aeroplanes since the late 70s. Look him up in white pages of Yahoo.com and tell him John from Yuba City told you to call him re: LS1 for your kitplane. George used to manufacture the Jaguars, but retired and has gotten out of the kitplane manufac end, but still builds engines for them. Be advised, the engine with gear redux and accessory drive built for 350+HP does come up to around $25K once it's ready to plug & play! His Jaguar also uses the Vortech Supercharger.
Cheers! Happy New Year!
Cabi~





