# Really, REALLY, basic engine queries

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#### wingandprop

##### Member
Hello everybody,

I know from reading this forum that some folks get a bit testy when they see others making technically inaccurate statements about engine or accessory design, installation, or function. That will not be a problem with this post. I say that because I am equipped with a nearly universal lack of knowledge about any of the above issues and will make no claim of knowing exactly how just about anything works. What little I do know is just enough to get myself in trouble. Indeed, it is my hope to stay out of trouble by getting your input on some very basic questions. Although the engine I am interested in is a Ford, my questions are not specific to that engine, so I have placed this question here in the general discussion.

To start with, my goal is to build an Airdrome Airplanes SE-5a. This actually avoids a lot of the preliminary arguments you sometimes see about whether an automotive engine is or is not a good choice for the airplane in the first place as the Hispano Suiza engine used in the original design was largely derivative of pre WW1 automobile racing engines. The arguments that are often raised about weight and power ratios for an automobile engine vs. a certificated engine don’t apply either because the original 200 hp Hisso was about 450 pounds, far heavier than the engine I am hoping to use, yet the new engine will deliver the same power as did the original Hisso. The debate over whether a re-drive should or should not be used, it’s weight, etc., also doesn’t have much impact as the original design used a re-drive, but one considerably heavier and less reliable than what is available today (it had the occasional, and rather unpleasant, habit of leaving the airplane and taking the propeller with it). In short, all the arguments you hear about whether an automotive engine is or is not a good idea have pretty much been pre-empted by the history of this design and the fact that I am not trying to maximize performance, but to duplicate it (at least to some degree).

The engine I am looking at is the normally aspirated Ford Duratec 37, the V-6 engine used in the Mustang and the F-150 pick up truck. It has 302 bhp which I would de-rate to 200 hp at approximately 4,000 rpm (based upon the various dyno tests I have reviewed for this engine). A precise weight is hard to come by, but it appears that this engine would be approximately 340 pounds.

Ford 3.7L V6 Specifications

Type: 3.7L DOHC 24-valve V-6
Manufacturing Location: Lima Engine Plant, Ohio
Configuration: 60-degree V-6, aluminum block and heads
Intake Manifold: Composite, slit plenum
Exhaust Manifold: Cast iron
Crankshaft: Forged steel
Redline: 6700 rpm
Throttle Body: 65 mm, electronic
Valve train: DAMB, 4 valves per cylinder, intake variable camshaft timing
Valve Diameter: Intake: 37mm
Exhaust: 31 mm
Pistons: High temperature cast aluminum alloy with low-friction coated skirts, low-tension rings
Connecting Rods: Cracked-powder metal
Ignition: Pencil coil
Bore x Stroke: 3.7 x 3.4 in/96.5 x 86.7 mm
Displacement: 224 cu in/3.696 cc
Compression Ratio: 10:5:01
Horsepower: 302 @ 6250 rpm
Horsepower per Liter: 71.5 (estimated)
Torque: 280 lb-ft @ 4500 rpm
Recommended Fuel: 87 Octane
Fuel Injection: Sequential multiport fuel injection
Oil Capacity: 5.5 quarts, with filter

* table from an earlier post by J3cubav8R re this engine, but it matches what I have seen elsewhere as provided by Ford (at least I tried to put it in table form)

The re-drive would be the Ballistic Gear Reduction unit Ballistic Gear Drives Gear Reduction Units for Airboat Applications . This unit has a long and reliable history in airboats and has also been used successfully by the developers of the (now awarded) STC permitting use of a Corvette engine in a Cessna 172. The re-drive would turn a four bladed 9 ½ foot diameter propeller using a 2.1:1 or 2.3:1 reduction ratio. The choice of gear ratio would depend on actual engine output as measured on a dynamometer. Original rpm with this size prop was approximately 1750 to 1800 rpm. The above reduction ratios should produce slightly lower rpm, but it will be fairly close. Use of a 1.8:1 ratio would let the prop spin too fast at approximately 2222 rpm at which point the blade tips would either be supersonic or very close to it. The original Hisso powered SE used a four bladed wooden prop and I would like to have the same, but that is not crucial by any means.

Ready for the questions? The most obvious one is whether there is anything about this engine or drive or the combination of the two (or the prop either for that matter) that raise any red flags? I have tried to think through these selections, but I am not an engineer, nor am I a mechanic nor have I ever done this before. My idea of fixing my car is to drive it to Christian Brothers Garage (whereupon I congratulate myself for getting there without having lost anything along the way). To say I am mechanically gifted would be an overstatement. The Airdrome SE, however, is a very simple design, as airplanes go, and it has good support from its designer. Also, I do pick up on the basics pretty quickly and after reviewing this site and others in some detail, and having reviewed information about the original design, having talked to the designer about his version of the SE and his views on engine options, weight and balance, etc., this seems to work. Frankly, the prop is the item I have done the least thinking about. Rightly or wrongly, I figure if it worked in 1917, it will probably work now. Am I missing anything obvious on my basic selections?

The next question may be a real hoot to you all, but it is one that has worried me considerably. In view of the heavy computerization of modern automobile engines, how do I go about modifying the computer to work properly in an airplane, or do I even try? Do I just throw it away and go with an iron, or in this case aluminum, dumb engine? Can you even do that nowadays? My automobile’s mechanic says I can, although you will obviously lose a lot of the efficiencies made possible by the computer systems. While he says that can be done, he has never actually done it himself and I tend to prefer experience to theory. My particular concern is with some of the “safety” designs of a modern automobile engine, like the protective measures that will shut the engine down rather than letting it significantly overheat. Bad idea in an airplane. An automatic engine shut off in order to protect the engine has the real potential to reverse my required priority (people first, engine last). That outcome would be reminiscent of a similar reordering of priorities in the F-16 some years ago. It resulted in the death of an excellent pilot, a previous ANG winner of the USAF Gunsmoke competition, when his attempts to pull out at low altitude were overruled by the aircraft’s flight controller in order to help extend the wing spars’ life span. So, how do you rework the computer in an automotive engine? Are there kits or programs that will take care of that? Are there people who do that? Do you just gut it? I am not averse to finding experts and paying them do their stuff. (Which, ultimately, is why I’m here in the first place, but without the paying part.)

Before I go further I should mention that I watched Stol’s superb review and explanation of his engine installation in his own airplane. It was extremely instructive and, to a novice like myself, incredibly intimidating. He points out so many issues that have to be considered and, while some of them won’t necessarily apply to my airplane (for instance, the cooling issue in my airplane is much simpler as my radiators are right there on the nose), others very clearly will apply. He pointed out how his mixture control was installed, but he did not say anything about mags, presumably because he retained the engine’s electronic ignition. Can mags be installed into an auto engine at an almost reasonable cost? I know electronic ignition is far more efficient, but I am still a bit leery of it in an airplane. I like the redundancy and mechanical reliability of mags vs. electronic ignition. Having been struck by lightning while driving my electronically dependent car a number of years ago (a convertible no less), I found it was very nearly totaled by that encounter and crazy unexplained electrical problems continued to pop up for years afterward despite the best efforts of an exceptionally good mechanic. Those problems eventually forced me to get rid of the car when its engine began shutting down spontaneously at inopportune moments, typically refusing any offers to restart for at least 45 minutes to an hour. Obviously not what you want to be worried about in an airplane and that was twenty years ago when engines were far less dependent on computers than they are now. So I am not a big fan of electronics over mechanical functions on the real backbone issues. I know mags are doable with enough money (as is almost everything), but are mags a bad idea in a modern auto engine? Why?

What about carb heat? I have read some articles asserting that carb heat wasn’t needed in current auto engine conversions because you won’t get carb ice, presumably because they are fuel injected, but Stol pretty well put that suggestion to rest by describing in detail how his system allows him to identify potential carb icing. Yet he didn’t mention actually having carb heat himself. Why? I assume Stol was talking about carb icing in a throttle body injector, correct? Would a throttle body injector be a good idea versus the multiport fuel injectors on this engine? Can you change from multiport injectors to a throttle body injector? Can you even have a mixture control in an injected engine without a throttle body injector system? Do throttle body injectors require carb heat? Once again, just to establish my card carrying Luddite status, could you use a carb on this engine? This once again harkens back to my distrust of an electronic system. (Do you see an emerging pattern?) Carbs are much simpler than is fuel injection, even than a throttle body injector, and more reliable, but are they even minimally functional in an application like this? Would there be a loss (or gain?) of horsepower if you converted to a carb? (I told you these questions were basic.)

I will stop for now as I don’t want anyone to hurt themselves by laughing so hard that they fall out of their chairs. That may be too late, but I will save my next questions until after you all have regained your composure.

Matt

#### deskpilot

##### Well-Known Member
Matt, I'm not going to try an answer your question 'cause I just don't know. What I will say though, is, thank you for a serious question, put so elegantly and with a twist of humour. I don't usually read long posts but I'm so glad I did read yours. Here's, like you, looking forward to the answers from the more knowledgeable amongst us.

#### haiqu

##### Well-Known Member
These questions tell me you're starting with the wrong engine. Get hold of something of that power already used in an aircraft and all these problems go away.

You're too far behind the eightball to do this yourself, and it would be cheaper to buy a certified engine than get someone else to develop this one for you.

#### Dana

##### Super Moderator
Staff member
You raise several issues.

First and foremost, though they look, like the original, realize that the airdrome replicas are just that, replicas.. Both the structure and aerodynamics are not original. As such, any analogy to the original engine is meaningless. Airdrome specifies 80-100hp, a VW or Geo conversion. The Ford engine you're proposing would be too heavy and too powerful.

Next, yes, the auto computer's programming would likely not be appropriate for an aircraft application. If you did keep the fuel injection, though, carb heat would be unnecessary as there's no carb (no venturi to expand and cool the air).

Dana

E

#### ekimneirbo

Thats a well written and thought provoking set of questions. While I hope you continue to learn about engines, the biggest red flag in my opinion is your professed lack of mechanical knowledge and computer understanding as related to engines. It is challenging for someone knowledgeable of engines to build a workable set up. Any setup contains a multitude of problems to be solved. While you are obviously intelligent, your lack of related knowledge and experience is where I see a big pitfall. This doesn't mean that you can't learn as you go, but it will prove difficult. There are so many engines available today and many of them contain newer technologies that must be dealt with. I'm a Chevy guy so I don't keep up with all the Ford engines and know nothing about the engine in question. Many of the newer engines have variable valve timing features and other incorporated tech in order to attain higher power and fuel efficiency. They just aren't as simply designed as past engines. Converting to a carb is reasonably easy, but what about driving the ignition? Chevy uses a reluctor wheel and sensors, so it has to run through a computer to work. You can probably adapt an electronic setup that doesn't actually use a computer, but it would be difficult to mechanically adapt a pair of magnetos as the engine contains no conventional gear to drive them. Thats what I mean about having some inate knowledge and experience in order to make decisions. Why not emulate what Ben Haas has done and follow a proven path? One other thing that concerns me is the large propellor you mentioned. If it made of metal, its going to generate some serious forces over a long leverage arm. Will the reduction drive you mentioned handle these kind of forces? Personally, I'm not laughing and like to hear from people who are trying to learn more. Thats why I use this site, to discuss and to learn, and hopefully to help. One thing I will say is that the more you learn from reading and observing, the more you will modify your choices of whats best for your dream. What seems like a great idea/choice often changes your opinion as you continue to learn. Good luck whatever you decide to do.

#### Bitshifter

##### Member
The engine I am looking at is the normally aspirated Ford Duratec 37, the V-6 engine used in the Mustang and the F-150 pick up truck. It has 302 bhp which I would de-rate to 200 hp at approximately 4,000 rpm (based upon the various dyno tests I have reviewed for this engine). A precise weight is hard to come by, but it appears that this engine would be approximately 340 pounds.

Ford 3.7L V6 Specifications

Type: 3.7L DOHC 24-valve V-6
Manufacturing Location: Lima Engine Plant, Ohio
Configuration: 60-degree V-6, aluminum block and heads
Intake Manifold: Composite, slit plenum
Exhaust Manifold: Cast iron
Crankshaft: Forged steel
Redline: 6700 rpm
Throttle Body: 65 mm, electronic
Valve train: DAMB, 4 valves per cylinder, intake variable camshaft timing
Valve Diameter: Intake: 37mm
Exhaust: 31 mm
Pistons: High temperature cast aluminum alloy with low-friction coated skirts, low-tension rings
Connecting Rods: Cracked-powder metal
Ignition: Pencil coil
Bore x Stroke: 3.7 x 3.4 in/96.5 x 86.7 mm
Displacement: 224 cu in/3.696 cc
Compression Ratio: 10:5:01
Horsepower: 302 @ 6250 rpm
Horsepower per Liter: 71.5 (estimated)
Torque: 280 lb-ft @ 4500 rpm
Recommended Fuel: 87 Octane
Fuel Injection: Sequential multiport fuel injection
Oil Capacity: 5.5 quarts, with filter

<-- SNIP -->

The next question may be a real hoot to you all, but it is one that has worried me considerably. In view of the heavy computerization of modern automobile engines, how do I go about modifying the computer to work properly in an airplane, or do I even try? Do I just throw it away and go with an iron, or in this case aluminum, dumb engine? Can you even do that nowadays? My automobile’s mechanic says I can, although you will obviously lose a lot of the efficiencies made possible by the computer systems. While he says that can be done, he has never actually done it himself and I tend to prefer experience to theory. My particular concern is with some of the “safety” designs of a modern automobile engine, like the protective measures that will shut the engine down rather than letting it significantly overheat. Bad idea in an airplane. An automatic engine shut off in order to protect the engine has the real potential to reverse my required priority (people first, engine last). That outcome would be reminiscent of a similar reordering of priorities in the F-16 some years ago. It resulted in the death of an excellent pilot, a previous ANG winner of the USAF Gunsmoke competition, when his attempts to pull out at low altitude were overruled by the aircraft’s flight controller in order to help extend the wing spars’ life span. So, how do you rework the computer in an automotive engine? Are there kits or programs that will take care of that? Are there people who do that? Do you just gut it? I am not averse to finding experts and paying them do their stuff. (Which, ultimately, is why I’m here in the first place, but without the paying part.)

Before I go further I should mention that I watched Stol’s superb review and explanation of his engine installation in his own airplane. It was extremely instructive and, to a novice like myself, incredibly intimidating. He points out so many issues that have to be considered and, while some of them won’t necessarily apply to my airplane (for instance, the cooling issue in my airplane is much simpler as my radiators are right there on the nose), others very clearly will apply. He pointed out how his mixture control was installed, but he did not say anything about mags, presumably because he retained the engine’s electronic ignition. Can mags be installed into an auto engine at an almost reasonable cost? I know electronic ignition is far more efficient, but I am still a bit leery of it in an airplane. I like the redundancy and mechanical reliability of mags vs. electronic ignition. Having been struck by lightning while driving my electronically dependent car a number of years ago (a convertible no less), I found it was very nearly totaled by that encounter and crazy unexplained electrical problems continued to pop up for years afterward despite the best efforts of an exceptionally good mechanic. Those problems eventually forced me to get rid of the car when its engine began shutting down spontaneously at inopportune moments, typically refusing any offers to restart for at least 45 minutes to an hour. Obviously not what you want to be worried about in an airplane and that was twenty years ago when engines were far less dependent on computers than they are now. So I am not a big fan of electronics over mechanical functions on the real backbone issues. I know mags are doable with enough money (as is almost everything), but are mags a bad idea in a modern auto engine? Why?

What about carb heat? I have read some articles asserting that carb heat wasn’t needed in current auto engine conversions because you won’t get carb ice, presumably because they are fuel injected, but Stol pretty well put that suggestion to rest by describing in detail how his system allows him to identify potential carb icing. Yet he didn’t mention actually having carb heat himself. Why? I assume Stol was talking about carb icing in a throttle body injector, correct? Would a throttle body injector be a good idea versus the multiport fuel injectors on this engine? Can you change from multiport injectors to a throttle body injector? Can you even have a mixture control in an injected engine without a throttle body injector system? Do throttle body injectors require carb heat? Once again, just to establish my card carrying Luddite status, could you use a carb on this engine? This once again harkens back to my distrust of an electronic system. (Do you see an emerging pattern?) Carbs are much simpler than is fuel injection, even than a throttle body injector, and more reliable, but are they even minimally functional in an application like this? Would there be a loss (or gain?) of horsepower if you converted to a carb? (I told you these questions were basic.)
A few points in no particular order, YMMV, IANAEB (I am not an engine builder), and various other disclaimers apply.
• Variable Valve Timing - VVT/VTech was invented because in the automotive world, engines have a very wide range of operating conditions they need to work well for. At idle and low rpm, low power settings you want to have much different valve timing than high rpm, high power settings. For instance, at high RPMs, inertial effects of the air mean you can open the intake valve before the exhaust valve is closed and the flow of air will help scavenge the exhaust out of the cylinder and draw in more charge. Also, you can leave the intake valve open as the piston is beginning its compression stroke. At low RPMs, this makes for a very poor idle and a lot of emissions when running at low RPMs. VVT lets the engine choose between 2 or more valve "profiles" to be better optimized for sitting at a red light or trying to pass someone on the freeway.
• Carb vs throttle body FI vs multipoint FI vs sequential multipoint FI - My understanding is a tuned carb vs fuel injection should be close to a wash in theory, in practice, the closed loop controls of fuel injection can provide some benefits. Better cold starting performance, with oxygen sensors, automatic mixture control. With high pressure injection systems, better fuel atomization. Multipoint injection, the fuel ends up very close to the intake valve, can have some cooling benefits for the intake valve, and usually considered to provide a more uniform mixture control to the various cylinders, but smaller orifices are more sensitive to crud in the fuel. Throttle body injection is simpler, one or two injectors to control rather than 4, 6, 8. The injector nozzles are larger so they are less sensitive to gum and getting blocked, lower pressures are needed to flow the right amount of fuel.
• Sequential multipoint is similar to multipoint, but each injector is controlled separately and opened appropriate to the timing of the intake valve. With regular multipoint, they connect two injectors that are 360 out of phase similar to wasted spark ignition systems
• Sensors and systems not on traditional (old) engines
• Anti-knock sensors - Some of the gains modern engines have on low octane fuels are related to antiknock sensors, if the knock sensor trips, the computer automatically de-tunes the engine (reduces power) because the fuel isn't good enough to support the power level
• Oxygen sensors - These allow for automatic altitude compensation. Along with the MAP (Manifold Absolute Pressure) and IAT (Intake Air Temp) which let you calculate the amount of fuel you *should* need, the oxygen sensor lets you check that value to ensure you are using up all the oxygen (or not quite all if you are automatically leaning the mixture)
• Crank position sensor - in combination with other sensors (throttle position, oxygen, MAP, how fast the throttle opens) lets you adjust the ignition timing to be closer to the optimum
Any engine can be converted to carbs, possibly not magnetos without significant machining to add the gears to drive the magnetos. The features that allow the more significant power output may exist in the car's computer or various other modules spread throughout the car. For instance the ignition module may or may not be a separate part.

A cam that was ground specific for the RPM range that you want to develop power in would be lighter and less complex than VVT. You can choose to give up some idle performance for a better optimized cam.

The timing and fuel curves are the results of lots of time spent on a dyno at engine design lab, however, since we aren't designing a grocery-getter, we don't necessarily have to spend much time outside of idle, cruise, and WOT. Without a dyno, it would be hard to perfect the curves, but in practice, with an oxygen sensor the ECU can "learn" what they should be. There are aftermarket ECUs that do this. Getting ignition timing correct would need some measure of engine output to optimize (dyno, torque meter on output shaft, etc)

There are projects such as MegaSquirt MegaSquirt - Wikipedia, the free encyclopedia to allow you to add EFI and now electronic ignition to an engine. I looked at this extensively when I was having trouble with my 4-pack of carbs on my motorcycle.

This is not meant to be comprehensive. There may be factual errors or things I've left out. Hope this was helpful.

-BitShifter

E

#### ekimneirbo

A few points in no particular order, YMMV, IANAEB (I am not an engine builder), and various other disclaimers apply.
• Variable Valve Timing - VVT/VTech was invented because in the automotive world, engines have a very wide range of operating conditions they need to work well for. At idle and low rpm, low power settings you want to have much different valve timing than high rpm, high power settings. For instance, at high RPMs, inertial effects of the air mean you can open the intake valve before the exhaust valve is closed and the flow of air will help scavenge the exhaust out of the cylinder and draw in more charge. Also, you can leave the intake valve open as the piston is beginning its compression stroke. At low RPMs, this makes for a very poor idle and a lot of emissions when running at low RPMs. VVT lets the engine choose between 2 or more valve "profiles" to be better optimized for sitting at a red light or trying to pass someone on the freeway.
• Carb vs throttle body FI vs multipoint FI vs sequential multipoint FI - My understanding is a tuned carb vs fuel injection should be close to a wash in theory, in practice, the closed loop controls of fuel injection can provide some benefits. Better cold starting performance, with oxygen sensors, automatic mixture control. With high pressure injection systems, better fuel atomization. Multipoint injection, the fuel ends up very close to the intake valve, can have some cooling benefits for the intake valve, and usually considered to provide a more uniform mixture control to the various cylinders, but smaller orifices are more sensitive to crud in the fuel. Throttle body injection is simpler, one or two injectors to control rather than 4, 6, 8. The injector nozzles are larger so they are less sensitive to gum and getting blocked, lower pressures are needed to flow the right amount of fuel.
• Sequential multipoint is similar to multipoint, but each injector is controlled separately and opened appropriate to the timing of the intake valve. With regular multipoint, they connect two injectors that are 360 out of phase similar to wasted spark ignition systems
• Sensors and systems not on traditional (old) engines
• Anti-knock sensors - Some of the gains modern engines have on low octane fuels are related to antiknock sensors, if the knock sensor trips, the computer automatically de-tunes the engine (reduces power) because the fuel isn't good enough to support the power level
• Oxygen sensors - These allow for automatic altitude compensation. Along with the MAP (Manifold Absolute Pressure) and IAT (Intake Air Temp) which let you calculate the amount of fuel you *should* need, the oxygen sensor lets you check that value to ensure you are using up all the oxygen (or not quite all if you are automatically leaning the mixture)
• Crank position sensor - in combination with other sensors (throttle position, oxygen, MAP, how fast the throttle opens) lets you adjust the ignition timing to be closer to the optimum
Any engine can be converted to carbs, possibly not magnetos without significant machining to add the gears to drive the magnetos. The features that allow the more significant power output may exist in the car's computer or various other modules spread throughout the car. For instance the ignition module may or may not be a separate part.

A cam that was ground specific for the RPM range that you want to develop power in would be lighter and less complex than VVT. You can choose to give up some idle performance for a better optimized cam.

The timing and fuel curves are the results of lots of time spent on a dyno at engine design lab, however, since we aren't designing a grocery-getter, we don't necessarily have to spend much time outside of idle, cruise, and WOT. Without a dyno, it would be hard to perfect the curves, but in practice, with an oxygen sensor the ECU can "learn" what they should be. There are aftermarket ECUs that do this. Getting ignition timing correct would need some measure of engine output to optimize (dyno, torque meter on output shaft, etc)

There are projects such as MegaSquirt MegaSquirt - Wikipedia, the free encyclopedia to allow you to add EFI and now electronic ignition to an engine. I looked at this extensively when I was having trouble with my 4-pack of carbs on my motorcycle.

This is not meant to be comprehensive. There may be factual errors or things I've left out. Hope this was helpful.

-BitShifter
Very good and very accurate explanation. Since we both mentioned the VVT feature in engines, I'd like to say a little more about it. The components used to make some of this new technology work is often subtly done and a builder would need to acquaint himself with a particular engine very thoroughly in order to be aware of them. Things like oil redirection, different lifters on some cylinders, and even the mechanical components for cam advance/retard which differ from from previous versions of the engines. Removal,replacement, or substitution of parts in these areas might be wise.......on the other hand, retaining them and making them work within the scenario of an airplane might prove to be wise. The point is that without not only a general knowledge of engines and EXPERIENCE with the general working and assembly of engines, a builder places himself in the proverbial swamp full of alligators.

One of my favorite sayings is :" Knowledge is of little use until experience has given it meaning"

#### wingandprop

##### Member
Wow! In tallying the responses, and by reading between the lines, I see Haiqu thinks I am a danger to myself and should be banned from the site, Ekimneirbo agrees I'm a danger, but would let me stay around if I don't touch anything while I'm here, and Dana is humoring me but doesn't think I did any research at all on this airplane before posting. BUT, nobody suggested I don't know how to dress myself, and nobody suggested my dogs were ugly! This is a 44% improvement over the last site I was on!

Actually, I do appreciate the responses. I am also impressed that Dana actually went to the Airdrome site to look at the airplane. That really was going the extra mile. He is mistaken, though, about the weight and power issues. I know what the site says, but the site doesn't tell the full story. Stated very briefly, the prototype Airdrome SE was built for a movie. The builder wasn't trying to sell it to a regular consumer and all he needed, or wanted, was an engine he was familiar with and which would be functional (get it off the ground for the cameras), reliable and easy to install. Hence the 100 hp VW engine that they had previously used on several of their partial scale airplanes. I have talked to Robert Bosley, the designer and owner of Airdrome Airplanes, about that VW engine and he says it is underpowered and its weight is too light for this airplane. The airplane needs much more weight in the nose. A 230 pound pilot will shift the cg so far aft that the airplane is unflyable. The reason he lists the VW engine on the site is simply because that's the only engine he's ever actually installed in the airplane, so that's all the specifications he has! If you look at the Geo engine he is suggesting, instead of it being a 100 pound engine, it is a 307 pound engine, and instead of WOT of 105 hp, the Suzuki 2.7 liter Geo engine has 183 hp at WOT Titan Aircraft - Engines . That compares with the Ford engine at 340 pounds and 200 hp WOT (as derated). The website is misleading on that point, and Bosley has said an engine in the 340 pound range would be "easy", even recognizing the need for a redrive and a radiator. I am not quite as far off base as a review of the site's web page would make me appear. I appreciate Dana actually going to look at the site though, very much. I also appreciate his confirmation of my understanding about the engine's current fuel injection, as distinguished from a throttle body injector, obviating the need for carb heat.

Ekimneirbo had a number of interesting comments, but as to his concern about the characteristics of a four bladed metal prop, there is no danger of that. No metal props during WW1. The SE's four bladed prop was all wood and they functioned quite well. Mine would be almost identical to what is pictured.

Haiqu mentioned certificated engines and I agree, that might be a better option and is certainly one that should be looked at, but what are the alternatives? A Lycoming O 360 is a fixed pitch 180 hp engine, but it costs, used, $28,000.00! And it doesn't come close to fitting. The SE was only 29 inches wide. Basic fit is part of the appeal of a 60 degree V-6 engine. Cheaper certificated engines are available, for about$12,000.00, but most of them I see are either high time or have had "minor" prop strikes...and some not so minor. A Ford engine can be had for $4000.00, brand new, or extremely low time, involved in rear end collisions, for$1000 to $2000.00. That gives me$26,000.00 R&D money right off the top! And have no doubt, I will not be the one turning the wrenches except on the simplest aspects of the engine installation. If you all read my original post carefully you would see there was a savings clause in the fine print, to wit: "I am not averse to finding experts and paying them do their stuff". I do understand my limitations. What I am really looking for is not whether I can readily do it myself, but whether this is feasible in the hands of someone who knows his stuff. I could do it, but it would take much more time, for training, etc., than I have available. I expect to build the airplane, but I expect I will likely have someone else do most of the engine work. Of course, that really puts me in no different position than I would be in if I went with a certificated engine to start with. In that case I would still be relying on engine experts, i.e. the guys at Lycoming or Continental, to have made the selected engine fully ready for use. Now, if there are other reasonably priced alternatives that will fit in this nose, and will produce the desired horsepower, I would be very eager to hear about them. The Suzuki 2.7L V-6, at $9000.00 (the Geo engine), would be an option at a good price, but it develops its hp at a very high rpm and would force me either to dramatically reduce my prop size or to run at an unacceptably high rpm a substantial amount of the time. It's WOT is 183 hp, but running the Ford engine at 200 (derated) WOT hp would let me run at a much lower speed with far greater economy and with much less engine wear. I am very open to other engines if they are out there. That 29 inch nose, though, is hard to overcome in an aircraft engine with this hp. As to Bitshifter, I very much appreciate all the effort in explaining the various systems. That was a very lengthy post, and I appreciate it. Ekimneirbo also elaborated on some of those issues. With those comments in mind, I guess I would go back to one of the very first questions I asked: are there people who rework the computer system(s) installed to control the various systems and how extensive a process is it? Surely, anyone who has ever converted one of the newer generation auto engines has had to address this issue. I've even seen an ad by an engine conversion shop (they are out of business now) that claimed that where others only changed 200 lines of code to convert an automobile engine to use in an airplane, that they converted over 1000 lines of code! That alone tells me that someone does, or did, know about this subject and was doing it commercially. Perhaps everyone going with auto engine conversions is sticking to pre-computer dumb engines? I would really be surprised to find that is the case. I would still be very interested in answers to the original questions, to the extent they haven't already been answered, but suggestions for alternative engines would also be high on my list. I hope this wasn't too long for deskpilot! Have a good evening all, Matt Last edited: #### autoreply ##### Well-Known Member Not much to add (though compliments for a well written OP), but you might want tocheck out Ebay or barnstormers.com for 2nd hand prices for engines. #### rv6ejguy ##### Well-Known Member HBA Supporter I'd pick an engine which has some flight history behind it. You might want to look at the 3.5L Honda V6 engines used by Titan as there are many of these flying. My advice is don't screw with the factory valvetrain because you think you know better. This is often a recipe for disaster. Most people don't have a clue about valvetrain testing, geometry and possible harmonics leading to broken valve springs or worse. This is a carefully tested thing by the OEMs. With a PSRU, you can gear the engine to work well with the stock powerband which is usually just fine. Single stage VVT is easily controlled by most aftermarket EFI systems. Forgive my possible bias, but putting carbs on an engine designed for EFI and distributorless ignition is a nasty thing to do. EFI is far more reliable than carbs- period. How many cars do you see broken down with EFI issues? How much maintenance do most EFI systems get in their entire lifetime? EFI/ EI is the single biggest advance in automotive reliability in the last 50 years. I've got well over 1 million km driving EFI cars and never walked home once in that time. You can check the signature link below if you want to know about aviation EFI. Another possible engine choice in this 200hp range which have flown a lot- Rover V8. One of our customers has 1200 flight hours on his now. Simple engine, no modern bells and whistles. Chevy 4.3L V6. Lots of flight hours on these too. That drive might bolt right up to this one. Last edited: #### akwrencher ##### Well-Known Member HBA Supporter How many cars do you see broken down with EFI issues? Excellent points, however, I do have to disagree with this one. I actually Do see allot of cars broken down with EFI issues. They all end up in my shop. I fixed at least three this year that were due simply to a bad ECT sensor. One had a new sensor installed, but it was shorted out, defective. I also replaced a few ECM's this year. There are a number of things that can cause an electronic system like this to fail, sometimes only partially though. I am not trying to start a debate on the merits or lack thereof on EFI. Only the importance of using a system that is designed for aviation. To the OP: If I wanted EFI I would only consider using a purpose built system. While automotive systems are quite reliable over all, the failure modes are all wrong for flying. Hope you find what you are looking for. Sounds like a great project. #### rv6ejguy ##### Well-Known Member HBA Supporter Excellent points, however, I do have to disagree with this one. I actually Do see allot of cars broken down with EFI issues. They all end up in my shop. I fixed at least three this year that were due simply to a bad ECT sensor. One had a new sensor installed, but it was shorted out, defective. I also replaced a few ECM's this year. There are a number of things that can cause an electronic system like this to fail, sometimes only partially though. I am not trying to start a debate on the merits or lack thereof on EFI. Only the importance of using a system that is designed for aviation. To the OP: If I wanted EFI I would only consider using a purpose built system. While automotive systems are quite reliable over all, the failure modes are all wrong for flying. Hope you find what you are looking for. Sounds like a great project. My personal time (30 years) is all on Toyota, Nissan, BMW, Hyundai with about 2/3ds of that million km using SDS (GM and Bosch sensors). What brands are you seeing failures on? Collectively, my family and close friends have about 10 million km on EFI cars. I know of one fuel pump failure and one MAP sensor failure in all that time- again, mostly Japanese and German cars. No factory ECU failures. Our SDS customer base stretches over 20 years, 200,000 flight hours and an estimated 24 million ground hours. I think I've sold less than 10 replacement air and coolant temp sensors in that time, maybe 6 MAP sensors, maybe around 8 TPSs. We do epoxy the thermistor to the cage on GM IAT sensors before sale to aviation customers. If you look at those numbers, the MTBF is pretty amazing. I've sold over 4000 injectors (Bosch and Siemens) and seen only 2 bad ones over that (manufacturing defect). In my opinion, a well designed EFI system is far more reliable than the engine it is attached to. I am old enough to remember working on carbs when I had a repair shop back in the 80s. Number one thing I fixed across all brands back then was carb problems. I'd agree with your thoughts on failure modes when using OEM ECUs in aircraft- the design goals are quite different. #### akwrencher ##### Well-Known Member HBA Supporter I've only been in the auto biz a few years, so don't have the long experience you do. I do spend half my time diagnosing electronics failures though. most of them on older vehicles, I admit. Replaced an ECM on friday on a geo tracker. 23 years old. Not bad service, really. Some systems are bulletproof, others are prone to problems. Mostly just pointing out that what works on cars is not the same as what you want on a plane. I guess the main problem I have with electronics is that you can't look at them and tell how worn out they are. I can take a carb apart and see what kind of shape it's in. If I ever am in the market for EFI, I would be looking for a proven, purpose built system such as the ones you sell, and I would want to know just what would happen if any given sensor were to fail. That said, I'm a little OCD, I like things I can inspect, and I live in some very rugged and unforgiving country. YMMV Anyhow, just throwing out my opinion, FWIW. It's a good thread. #### rv6ejguy ##### Well-Known Member HBA Supporter I've only been in the auto biz a few years, so don't have the long experience you do. I do spend half my time diagnosing electronics failures though. most of them on older vehicles, I admit. Replaced an ECM on friday on a geo tracker. 23 years old. Not bad service, really. Some systems are bulletproof, others are prone to problems. Mostly just pointing out that what works on cars is not the same as what you want on a plane. I guess the main problem I have with electronics is that you can't look at them and tell how worn out they are. I can take a carb apart and see what kind of shape it's in. If I ever am in the market for EFI, I would be looking for a proven, purpose built system such as the ones you sell, and I would want to know just what would happen if any given sensor were to fail. That said, I'm a little OCD, I like things I can inspect, and I live in some very rugged and unforgiving country. YMMV Anyhow, just throwing out my opinion, FWIW. It's a good thread. Your point about how an ECU deals with a sensor failure in an aircraft application is very important- many OEM ECUs go into limp mode which does not leave you with enough power for level flight usually and there are many other things that can command power reductions. It's not uncommon for automotive ECUs these days to have over a million lines of code in the program. #### deskpilot ##### Well-Known Member Wow! In tallying the responses, ......................................... I hope this wasn't too long for deskpilot! Have a good evening all, Matt Not too long Matt. Another well written piece that results in a great debate. Keep it going. FWIW, I drive an Australian Ford Falcon, 4.2ltr, duel fuel, straight 6 and just love it. Bought as an ex demo car with 5K on the clock, it's now just short of it's 10th birthday and still only has 96K on the clock. The secret to longevity is change the oil regularly and occasionally, give it a good blast of speed to loosen up any deposits in the oil lines. It reaches 160kph (100mph) all too easily and so far, the police haven't caught me doing it. (our limit in the country is 110kph.) I'm not averse to taking it faster but at 72, my reaction time is not as good as it once was. E #### ekimneirbo Wow! In tallying the responses, and by reading between the lines, I see Haiqu thinks I am a danger to myself and should be banned from the site, Ekimneirbo agrees I'm a danger, but would let me stay around if I don't touch anything while I'm here, and Dana is humoring me but doesn't think I did any research at all on this airplane before posting. BUT, nobody suggested I don't know how to dress myself, and nobody suggested my dogs were ugly! This is a 44% improvement over the last site I was on! Actually, what I'm trying to convey here is that if you don't have the experience to do a "hands on" conversion due to mechanical and electrical experiences accumulated thus far in your life....then a successful conversion is not very likely. I love to see people pursue their dreams, especially automotive and aero dreams, and am a huge proponent of auto engines in airplanes. Relying on/paying others to do the bulk of the work is OK if you have plenty of money, but you you will still need to be able to co-ordinate and bring together the results. If you think you can make this idea work, then go for it. Actually, I do appreciate the responses. I am also impressed that Dana actually went to the Airdrome site to look at the airplane. That really was going the extra mile. He is mistaken, though, about the weight and power issues. I know what the site says, but the site doesn't tell the full story. Stated very briefly, the prototype Airdrome SE was built for a movie. The builder wasn't trying to sell it to a regular consumer and all he needed, or wanted, was an engine he was familiar with and which would be functional (get it off the ground for the cameras), reliable and easy to install. Hence the 100 hp VW engine that they had previously used on several of their partial scale airplanes. I have talked to Robert Bosley, the designer and owner of Airdrome Airplanes, about that VW engine and he says it is underpowered and its weight is too light for this airplane. The airplane needs much more weight in the nose. A 230 pound pilot will shift the cg so far aft that the airplane is unflyable. The reason he lists the VW engine on the site is simply because that's the only engine he's ever actually installed in the airplane, so that's all the specifications he has! If you look at the Geo engine he is suggesting, instead of it being a 100 pound engine, it is a 307 pound engine, and instead of WOT of 105 hp, the Suzuki 2.7 liter Geo engine has 183 hp at WOT Titan Aircraft - Engines . That compares with the Ford engine at 340 pounds and 200 hp WOT (as derated). The website is misleading on that point, and Bosley has said an engine in the 340 pound range would be "easy", even recognizing the need for a redrive and a radiator. I am not quite as far off base as a review of the site's web page would make me appear. I appreciate Dana actually going to look at the site though, very much. I also appreciate his confirmation of my understanding about the engine's current fuel injection, as distinguished from a throttle body injector, obviating the need for carb heat. Ekimneirbo had a number of interesting comments, but as to his concern about the characteristics of a four bladed metal prop, there is no danger of that. No metal props during WW1. The SE's four bladed prop was all wood and they functioned quite well. Mine would be almost identical to what is pictured. What does a large four bladed wooden prop cost these days? Will your combination make enough power to bring a prop this large up to speed when needed....ergo, how much power will it take to make it turn under load? I would identify that need before selecting an engine to drive it. View attachment 34039 Haiqu mentioned certificated engines and I agree, that might be a better option and is certainly one that should be looked at, but what are the alternatives? A Lycoming O 360 is a fixed pitch 180 hp engine, but it costs, used,$28,000.00! And it doesn't come close to fitting. The SE was only 29 inches wide. Basic fit is part of the appeal of a 60 degree V-6 engine. Cheaper certificated engines are available, for about $12,000.00, but most of them I see are either high time or have had "minor" prop strikes...and some not so minor. A Ford engine can be had for$4000.00, brand new, or extremely low time, involved in rear end collisions, for $1000 to$2000.00. That gives me $26,000.00 R&D money right off the top! And have no doubt, I will not be the one turning the wrenches except on the simplest aspects of the engine installation. If you all read my original post carefully you would see there was a savings clause in the fine print, to wit: "I am not averse to finding experts and paying them do their stuff". I do understand my limitations. What I am really looking for is not whether I can readily do it myself, but whether this is feasible in the hands of someone who knows his stuff. I could do it, but it would take much more time, for training, etc., than I have available. I expect to build the airplane, but I expect I will likely have someone else do most of the engine work. Of course, that really puts me in no different position than I would be in if I went with a certificated engine to start with. In that case I would still be relying on engine experts, i.e. the guys at Lycoming or Continental, to have made the selected engine fully ready for use. Now, if there are other reasonably priced alternatives that will fit in this nose, and will produce the desired horsepower, I would be very eager to hear about them. The Suzuki 2.7L V-6, at$9000.00 (the Geo engine), would be an option at a good price, but it develops its hp at a very high rpm and would force me either to dramatically reduce my prop size or to run at an unacceptably high rpm a substantial amount of the time. It's WOT is 183 hp, but running the Ford engine at 200 (derated) WOT hp would let me run at a much lower speed with far greater economy and with much less engine wear. I am very open to other engines if they are out there. That 29 inch nose, though, is hard to overcome in an aircraft engine with this hp.

As to Bitshifter, I very much appreciate all the effort in explaining the various systems. That was a very lengthy post, and I appreciate it. Ekimneirbo also elaborated on some of those issues. With those comments in mind, I guess I would go back to one of the very first questions I asked: are there people who rework the computer system(s) installed to control the various systems and how extensive a process is it? Surely, anyone who has ever converted one of the newer generation auto engines has had to address this issue. I've even seen an ad by an engine conversion shop (they are out of business now) that claimed that where others only changed 200 lines of code to convert an automobile engine to use in an airplane, that they converted over 1000 lines of code! That alone tells me that someone does, or did, know about this subject and was doing it commercially. Perhaps everyone going with auto engine conversions is sticking to pre-computer dumb engines? I would really be surprised to find that is the case. Yes there are loads of people who reprogram computers.....all with differing levels of knowledge on the subject. Many OEM computers have been used in conversions, but some of them have a lot of unknown codes and safety devices built into them. Subaru engines went thru a learning curve because of a code which shut down their power when held WOT for a certain period of time (takeoff). Don't remember the exact details on that, but it created problems. There are self learning aftermarket systems available now thru companies like FAST. Plug it in, set the basic engine parameters, and it puts a basic program in place. Then it adjusts for best condition by comparing sensor readings. You can then modify those settings with a handheld control if you wish.

I would still be very interested in answers to the original questions, to the extent they haven't already been answered, but suggestions for alternative engines would also be high on my list.

I hope this wasn't too long for deskpilot!

Have a good evening all,

Matt
.....

#### rv6ejguy

##### Well-Known Member
HBA Supporter
Before selecting any ECU for an aircraft, you'd be well advised to find out what they will do in the event of a sensor failure by unplugging the sensors one by one with the engine running at WOT. This has been my business for 20 years and I can tell you every OEM ECU reacts differently and people have been bitten by Ford, GM, Subaru and Suzuki ones along with a bunch of aftermarket programmable ones. Airplanes have forced landed and people have been hurt and even killed from this stuff and plenty of aircraft written off. This is an important point to research before you do an auto engine conversion.

With 100s of thousands of lines of code, it's unlikely anyone other than the original person writing the code can understand and predict the outcome of multiple out of limit parameters so it's simply best to run your own tests.

#### wingandprop

##### Member
Lots to respond to this time around, and thanks to all who have provided input. Clearly, however, the folks who make fun of GIs for their constant use of acronyms have never hung out around you guys. I spend half my reading time here Googling and Wiki-upping what seems to be an endless stream of random letters. But that is good, you guys are teaching me exactly what I asked for: thank you.

Now on to your comments. Because it’s so long, I will break this into two posts, the first one dealing with the various engine recommendations and the second with the electronic issues.

...you might want to check out Ebay or barnstormers.com for 2nd hand prices for engines.
Actually, eBay is where I was getting my numbers on the “minor prop strike” engines previously. The real problem with certificated engines, though, is just getting them to fit. An SE’s nose is only 29 inches wide. The valve covers for the engine extended outside the engine compartment wall, but that was all. I have not found a certificated engine in the 180 to 225 hp range, however, that is less than 31 inches wide. In fact, most are closer to 33 or 34 inches, or more. That fact raises an important issue.

To explain, here is an SE with the original nose design:

And here is what a reproduction looks like using a certificated engine (Ewwww!):

A lot of you, maybe even most of you, will look at that and say “What?”, but that really serves to underscore a big difference between the attitudes of folks involved in building an RV6 or a Starduster versus someone building a reproduction of a specific historic airplane. The modern builder’s goal is not to produce an airplane that exactly matches the original design in every detail, but to produce an airplane of the general design that will perform at or above the expectations for that type. A major rework of the airplane’s nose that dramatically improves the airplane’s performance may be a no brainer to an RV builder, something others will congratulate him on and even seek to emulate in their own aircraft. When you are trying to reproduce the appearance of an historic airplane, though, you have much less freedom concerning the external appearance of the airplane. The reproduction builder’s goal is not performance, as it is for the RV builder. Instead it is the very appearance of the airplane. As a result, every variation in the appearance detracts, to some degree, from the basic goal in building a reproduction airplane.

Of course, that goal is not absolute and the question of how much variation is acceptable will vary from builder to builder. Construction of anything other than an exact replica is a compromise to start with. The airplane in the second photo has a builder who chose a certificated engine and (I think) a part scale design, choices that were different than I would make, but only as a matter of degree. By building an Airdrome SE, rather than one from the original RAF plans, I have made a similar compromise. My original intention was to build from the factory drawings, but, as a couple of you have pointed out, experience can be...."distressing" (the site bylaws prohibit obscenity). Having experienced restoring and driving an old car, I know the headaches inherent in maintenance and operation of antique designs. The fact that it was an every day driver in 1936 does not mean it is still good as an every day driver in 2014. It is still a beautiful design, but maintenance is (or was for me) a constant headache. That negative experience is why I abandoned the idea of an exact replica in favor of the Airdrome machine; a look alike reproduction with modern construction. But there are limits. If my airplane doesn’t even qualify as a “look alike”, why bother? I may just as well go with an Acroduster and paint roundels on it. The nose of my airplane needs to look like the original machine and, unfortunately, I have found no certificated engine that can fit within that 29 inch wide nose. Exposed valve covers, per the original, are fine, but its something else entirely to have the cylinder heads waving in the breeze like an olive drab Cub. I haven’t found a Lycoming or Continental that can fit within the SE’s delicate, petite, little nose.

As to rv6ejguy’s engine suggestions, the Honda V6 as used by Titan Aircraft, has a weight problem. The Ford engine is approximately 340 pounds while the Honda is 416 pounds. Also the Honda used by Titan produces the 200 hp I am looking for as my WOT hp at significantly higher rpm than does the Ford. That has implications for economy and wear, the latter of which strongly effects reliability. Titan is, I believe, using the Honda J-35 engine with cast iron cylinder sleeves. The Honda J-37, however, dumped the iron sleeves and is lighter, but I don’t know how much lighter. Also, the J-37 has a power curve much more comparable to the Ford’s. It may also be that much of the experience with the J-35 might transfer to the J-37. That would be a huge benefit. It is a 60 degree engine so it should easily fit in my nose. The J-37 engine might be a realistic option, one with at least some (related) track history...sort of, but weight may still be an issue.

Although its simplicity is extremely appealing, lack of power and (possibly) size are issues for the Rover V-8 (the Rover name actually covers a lot of engines and if you have a particular one in mind, please let me know). At 318 pounds the weight would be a winner. BHP is only 218, though, so if I derate the engine to WOT of about 3000 to 4000 rpm, the Rover will be well under the Ford’s 200 hp WOT.

Lastly, the 4.3L Chevy V-6. The earlier versions really did not produce the same power as the Ford so, once again, I would have to run at much higher rpm for the same hp as compared to the Ford, although (in the Chevy’s last versions) it would not be as high as the Honda and nowhere near as high as the Rover. It is a 90 degree engine, so I was concerned that fit might be a problem, but I just went out and measured the short block Chevy V-8 which now resides in my Buick, which engine I understand has the same width as the V-6, and the block was about 21 inches wide, so it should fit pretty easily in the SE’s nose. I have seen a comment on this site from RJW dismissing this as a bad engine, but he gave no explanation. My own understanding is that these engines are very well regarded and very reliable. I don’t have enough mileage on my short block V-8 to really say, but it has certainly not given me any problems to date. The biggest problem with this engine, other than the lack of power, however, is its weight. This is a cast iron engine and weighs in at 425 pounds! That’s 100 pounds more than the Ford and with a lot less power. On the plus side, however, this is an old enough design that it probably could be reverted entirely to dumb iron engine status.

The new Chevy V-6, the LV3, looks much more promising. It is essentially comparable to the Ford across the board. BHP is a little less (by 20 hp), but since I will be de-rating the engine to the 3000-4000 rpm range for my WOT power setting, I won’t use that anyway. Plus, the Chevy torque is actually higher, something WW1 airplanes really need for those 9 ½ foot propellers, so that is an acceptable trade off. I’ve seen weight estimated around 360 pounds, a bit higher than the Ford, but not too bad. Width is 25.2 inches, so it is an easy fit in the nose. This one is worth thinking about.

Info on the LV3 V-6:

http://www.gmpowertrain.com/2013_pdf/F3_Gen5_4.3(LV3)_Truck_020414.pdf

GM 4.3 Liter V6 EcoTec3 LV3 Engine Info, Power, Specs, Wiki | GM Authority

What does a large four bladed wooden prop cost these days? Will your combination make enough power to bring a prop this large up to speed when needed....ergo, how much power will it take to make it turn under load? I would identify that need before selecting an engine to drive it.
As for power, the engine (assuming the Ford) will have the same WOT hp, the same cruise hp, and the same rpm and torque at each of those settings as did the original (plus or minus a few percentage points either way). There should be no problem with this prop and power. If you think I’m missing something about that, though, I am eager to hear your thoughts.

I don’t know the price. I would suspect it will be about as much as two two bladed props, but the question of cost really doesn’t much enter into it. Again, an RV builder will be looking at a glass cockpit and all the latest gadgets. The repro builder has other concerns and if they enhance the appearance, you go with them (or at least you want to). I won’t even have an artificial horizon, much less a glass cockpit! I have different interests.

All you RV jockeys better start checking six! (Who am I kidding? I couldn't catch an RV from six if I mounted an auxiliary outboard!)

Matt

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#### ekimneirbo

What are your plans for getting the thrust line in or near the correct location ? Are you planning to run a reduction drive in order to achieve the rpms you are talking about? If you run a reduction drive what will the combined weight of the set up be?
What hp are you wanting to attain? What was the weight of the original engine in an SE ? What was the original hp rating?

#### wingandprop

##### Member
What are your plans for getting the thrust line in or near the correct location ? Are you planning to run a reduction drive in order to achieve the rpms you are talking about? If you run a reduction drive what will the combined weight of the set up be?
What hp are you wanting to attain? What was the weight of the original engine in an SE ? What was the original hp rating?

What are your plans for getting the thrust line in or near the correct location ? Mount the engine so that the prop is in essentially the same location(s) as was the original. That will actually be pretty easy as the centerline was moved up and down in the course of gearing and ungearing the engine during the war. They were not as picky about those sorts of things as some of us are today. But just look at the nose! It has the nose of a 1990 Mack truck! Line of thrust for its own sake wasn't nearly as big a concern as keeping the engine high enough that the prop would keep clear of the sod on the bottom end (without raising the underbuilt landing gear any higher) and maintaining clearance of the Lewis gun's line of fire over the top of the propeller arc on the top end.

Are you planning to run a reduction drive in order to achieve the rpms you are talking about? If you run a reduction drive what will the combined weight of the set up be?Yes, as I set out, the re-drive would be the hellical Ballistic Gear Reduction unit Ballistic Gear Drives Gear Reduction Units for Airboat Applications. It is 66 pounds, including dampener. The engine is 366 pounds (earlier I said 340 lbs., from memory, but I have checked it again and it is 366 pounds) for a total of 432 pounds.

What was the weight of the original engine in an SE ? The original Hispano was 445 pounds (it was regarded as a very light engine), not including its reduction gear (or its exhaust or radiator: the SE has very long exhaust pipes for an airplane).

What hp are you wanting to attain? I would limit it to 200 hp WOT. The Ford engine does that hp at approximately 4300 rpm. That number is based upon private dyno tests on various stock 2011 Duratech 37 powered POVs, both F 150 and Mustang. Obviously there are variations between those results, but they are surprisingly close to one another. Incidentally, none show the 305 bhp claimed by Ford. A 2.5 reduction gear, one of the standard reduction gears available through Ballistic Gear, would reduce that to 1750 rpm. That is exactly the 200 hp WOT rpm on the original engine. Cruise was 1,500 rpm.

By the way, thanks for being a good sport about my use of your initial post in a (vague) attempt at humor. Obviously you did not tell me I was not allowed to touch anything, but I would not have blamed you if you had. I started to report that one of the folks did say my dogs were ugly and that I didn't know how to dress, but that was just a little too close to the truth for me.

Matt