IS there an interest in low RPM High HP V-6,8,10,12?

Do you guys think that there would be an interest in low RPM high horsepower aircraft engines.

Like for example i designed a V-8 that would produce 600HP at 3,200RPM, a V-10 that would produce 800HP at 3,200 and a V-12 that will develop a whopping 1,000 HP at 3,300RPM.

Now this is with low boost superchargers added, there are some differences, The V-12 i designed will pump out about 2,200HP at 3,300 running full boost. (that is for my P-51 i want).

I designed the superchargers for altitude and gear reduction boxes as well for these engines. If you haven't guessed i want to get up high as well as have the HP and TQ to get up and cruse at 400MPH on 3/4 throttle.

However with all of this in the back burner and alread done with(well most of) i wasn't sure if there was a market for them.


DO you guys think that there would be an interest in a V-6 and a V-8 Design, i know that there have been discussions and that auto conversions are the only alternative to that of Lycomings and COntental engines, but im just curious.

The V-8 design was never finished, i moved up to a V-10 because the V-8 couldn't do what i wanted it to do.

I think for any such engine to be successful it needs to be proven to be at least as reliable as your typical aircraft engine, cannot cost more than a new lycoming, and cannot weigh significantly more. On top of that one or more of the following would need to be improved to make it really worth it: efficiency, overhaul cost, type of fuel burned (ie mogas or diesel compatible), or a truly significant reduction in weight.

I'm sure I'm missing something important but that is my .02 cents.

Yup. And 3300 RPM is an awkward place for a big engine. It's too low to really max out the hp/lbs of current technology, but it's too high to use direct drive for most applications. Seems like a bad compromise for most purposes.

Originally Posted by addaon

Yup. And 3300 RPM is an awkward place for a big engine. It's too low to really max out the hp/lbs of current technology, but it's too high to use direct drive for most applications. Seems like a bad compromise for most purposes.

We are talking geared engines here, no?

Whether there is a market for such things - you can always assume that if you build them, they will come...

Like Jake said, it needs to be as good, cheaper and as light or lighter than what you can buy right now. Or at least two out of those three to make it worthwhile. Not that there is much competition in those areas of 600 hp and up.

But if you're doing a geared engine, why not redline it at 5000 - 6000 rpm and get 50% more power for the same weight, and make up for it on the gear ratio? 5000 rpm seems sustainable for reasonable TBOs with modern engine design, so the only real reason I can see for going much below that is if you want direct drive.

Originally Posted by pepsi71ocean

...i designed a V-8 that would produce 600HP at 3,200RPM, a V-10 that would produce 800HP at 3,200 and a V-12 that will develop a whopping 1,000 HP at 3,300RPM...

Build it, test it, and fly it, and then people might take notice. Otherwise it's just like all the other "dream" engines that their designers are going to put into production Real Soon Now...

-Dana

You do not need a parachute to skydive. You only need a parachute to skydive twice.

Originally Posted by Dana

Build it, test it, and fly it, and then people might take notice. Otherwise it's just like all the other "dream" engines that their designers are going to put into production Real Soon Now...

Just like the "Revolutionary New Engine" that used to appear about every third month in Popular Mechanics and Mechanix Illustrated when I was a boy. This was in the late 50s and 60s and 70s, at a time when cars were using those terribly antiquated inline fours and sixes and V6s and V8s and a few used the opposed fours and sixes. I could hardly wait for these new designs to show up in cars and make everything so much better, and we'd convert these nice light and powerful engines to aircraft use, with their fantastic .25 BSFCs.

Well, here we are, 40 and 50 years later, and cars are using...let me see...inline fours and sixes and V6s and V8s and boxer fours and sixes. The V10 is a marketing idea that has little discernible merit that I can see. The Mazda rotary has had rather short rotor tip seal life but is powerful and in aircraft it tends to present cooling issues. And today I hear that the hybrids selling here in Canada have a way of freezing their occupants in winter, since the tiny engine often doesn't even run (or run enough to produce any heat) when used downtown and there's no other source of heat. Such wonderful advances. And airplanes are using aircooled boxer fours and sixes and maybe an eight (IO-720) that all look an awful lot like the Continental A-40 of 1935 or so.

Dan (in cynical middle age)

Im answering these in order of the postings, forgive me if i repeat myself.


Jman: On the weight issue that i can say could be an issue. especially on the 600HP model of the V-8. There is a smaller version that could be built that would weight alot less. The Current V-8 is 750cid. However I could modify and shrink the cylinder size down to help lighten the weight and the HP as well.

The engine is direct injection which would help improve efficiency, Low RPM would help increase TBO well beyond that if what i think is normal for an automotive conversion. The best part is the V-8 and V-10 models were designed to run on 93+ pump gas. They all utalise Diesel engine filters, pre oil lubrication, block and oil heating etic. depending as well on what the customer would want. Pre-Lube is standard.

The V-6 and V-8 would use .45BSFC while the V-10 and V-12, .55.

However, the engines are all liquid cooled, they all have superchargers and inter coolers as well. All are made from aluminum and steel for lightness and durability. The heaviest part of the system would be the cooling system IMO.

I don't know what a Lycomings or contental IO-720cid is but im sure the V-8 would weight in around 600lbs if not slightly more.

addaon: The reason i chose 3,300 is because ive worked on and been around big block engines. 427, 454, 502's. Ive found that marine engines where the RPM's are usually kept below 3,400 and where the engines were run at a constant 3,200 rpm's lasted the longest(nearly 800 Hours TBO). All engines have a gear reduction box that will be made from billeted steel and use a .499:1 .491:1 or a .450:1 reduction for efficiency and multiplication of HP and TQ.

Reddrive options

.499:1 will run 3,200RPM to 1596 Propeller RPM
.491:1 will run 3,200RPM to 1571 Propeller RPM
.450:1 will run 3,200RPM to 1440 Propeller RPM
.450:1 will run 3,400RPM to 1530 Propeller RPM

The V-6 will run the .450 option and the V-8 and V-10, V-12 will run any option based on the needs of its owner.
The V-6 reline would be closer to 3,400.

PTAirco: In theory this engine should be stronger and more durable then the Lycoming and Contential engines.

I could make lower HP engines out of it, hell dropping the Ve from 120 and 130% to that closer to 90 or so wuld increase TBO and reliability by alot. I am thinking of marketing the larger V-10 and V-12's as racing engines, while the V-6 and V-8 would be more for people with larger airplanes who want extra HP and airspeed without sacrificing reliability.

addaon: These engines are designed for very low RPM, IMO anything over 3,500 would add incredible stress and wear and tear, considering they all sport 8-10 inch connecting rods 4-6 inch strokes. In my opinion these engines would produce a horiable harmonic moan at any rpm's above 3,500 because of the weight of the connecting rods and the piston speeds.

Yes with modern engines you can run high rpm, however we must look at marine engines more then automotive engines since Marine engines run harder for longer periods of time. And as such Marine engines suffer the same work stresses that airplane engines do.


Dana: I was considering building 3 V-12's 2 for a speed boat and 1 for my airplane.

I think a speed boat might help advertise the engines while the airplane is being built.




Does anyone have any other questions? ide like some im interested and any points of view.

How exactly would you produce these engines? Make your own patterns for casting heads/blocks? What type of casting - traditional sand casting, lost foam? Forgings for cranks and rods? Utilize existing components?
Carve everything from solid with CNC machinery?

Outside of what's been discussed above, the other critical question is whether you're going into this for your own needs or whether you're serious about turning it into a business. Based on the performance numbers you listed earlier, I doubt you'd sell enough to even recover your investment.

First of all, despite a perceived interest in larger engines, the fact is that there is very little application out there short of someone doing a ground up development of a scaled WWII replica, and those are very few and far in between. Furthermore, those doing that level of work generally have their engines selected before the first chip is cut. This then means that you'd need your engine(s) developed, tested and properly marketed before you'd get a significant amount of real interest from those who'd have actual need.

Then, outside of something like an Epic, there are very few airplane kits (or other projects for that matter) that are sizable enough to take on something like a V10 or V12. Even a V-8 has limited application in the market. Furthermore, airplanes like the Epic tend to be configured about a turbine, which means that a recip would be an unlikely choice simply because it would not fit within the airframe's weight and balance criteria

The other thing to consider is that the type of person who decides on a high value kit like an Epic or Legacy is generally a relatively conservative individual, which means that he's not likely to consider an engine too far from the mainstream. As such, dollar for dollar, you're in a realm where things like price aren't too much an issue and now you're going up against the established and proven products like the bigger Lycs and Continentals, and the turbines. So again we're back on the subject of establishing a market presence, including a reputation for quality and dependability. Compared to the others, the only way you're likely going to reach an equivalent level of consideration is to go through certification.

Then you need to consider the performance. Your numbers look good but in examining the more conventional applications (especially in the 200 to 300 hp range) you'll have to match the performance required for the airframe and available props. Given the plethora of conventional Lyc and Cont based airframes, your engines will need to match the prop parameters of the most commonly available props. This means that your design goal needs to be more like 2,400 to 2,600 rpm, not 1,500.

If you take at least a brief look at the market and its history, you'll most likely find that your biggest potential number of sales will be in the range of 200 hp, with about 150 hp being the lower end and about 300 hp at the top. Then, to beat the name recognition and reputation of the certified products, your engines will have to sell at less than half that of the certified units. So that brings up the bottom line: Can you develop, prove and market an engine or line of engines with that type of business model? If not, best to work at just what you need. That way you'll still get what you were after and the investment will seem worthwhile. If you sell a few then great! If not, you still met your needs.

PTAirco: The engines are modular, they are to be assembled is a very similar fashion that the Rolls Royce Merlin was. The engine consist of a lower block section where the crank skirt and gear reduction housing are molded in using a wax impression molded around sand then the aluminum is put in. the cylinder blocks are then assembled by using steel cylinder sleeves surrounded by a jacket of water. these sleeves fit into a lip that i made in the bottom of the block. then a giant aluminum rounded rectangle shape is placed around the length of the cylinders on the bank. To help picture this think of a cardboard box with the top and bottom removed. now place that box on top of flat plate and add cups inside the cups represent the cylinder sleeves and the heads would bolt on top of it. The heads are then attached to the lower block(where the skirt is) and then forms a sandwich where the cylinder sleeves and the water jacket housings in the middle. there are 20 bolts around the cylinder (the V-12 will have 24) and an additional 10 are set around the water jacket. the water jacket is then fulled with coolant to cool the cylinder sleeves.

The engines will use forged steel cranks and connecting rods, the rods will be shot peened while the crank will be nitrised. the pistons will have enlarged wrist pins, and the pistons will be made from aluminum. the pistons will also be elongated and have 4 piston rings. Depending on engine configuration most engines will have between 7.5 and 9.25inch connecting rods.

the end of the crankshaft has gear on it, and the gear goes to the reduction housing, which the back plate is molded into the lower engine housing(where the skirt is)

The backside (opposite of the gear housing) will have the crankshaft come out where it will turn several accessory gears. ie. the injection pump, magnetos, supercharger gears oil pump, water pump and alternator, and battery charger.

The accessories will be driven by gears, with the crank shaft begin the main gear and the accessories rotating off of that.

This gear housing design is similar to what is used in the Cummings Turbo Diesel engine. (thus where i got the idea from.

The engine has a single camshaft down the middle where it uses solid lifters and tappets, driving a 4 valve per cylinder configuration. The camshaft will run at 50% the speed of the crankshaft.

To prevent wear and tear to the solid lifters there will be an electric oil pump that will fill up the heads and the cam valley before engine is started.


If you want me to go more in-depth let me know, if i can get a working computer i could draw up something to help explain it out.



orion: So i would need gear rations closer to say .700 then instead of .491.

Also, what you say makes sense 200-300HP isn't that hard to get out of any engine even from a 4 cylinder to a V-6. I'm sure with some basic calculations i could see a easy 300HP out of as V-6 at 3,300rpm. The question is weather people would go for that over a lycomings or a IO. Even if i can get the engines certified would there be a market for smaller engines then that would provide the HP and TQ.

If suck i could build a 360cid that can pump out 325HP at say about 3,000 rpm running on diesel in that case.


Keep the questions coming, i hope people don't think im in dream land, for the V-12 will be built someday, i want my Mustang, lol

I don't think you're in dreamland, I just think it's a BIG project. I have often toyed with the idea of scratchbuilding engines and have often been appalled by the cost quoted to me by foundries and machine shops. But there are exceptions to be found; I once had a gearbox housing cast in aluminium (solid, no core) and they did it for about $75, from my own pattern. CNC machine shop time goes from about $100-150 an hour around here. I would not even know where to go to get a blank for a crank forged, never mind imagine the cost.

I don't think anything is impossible in the world of machinery, but I would put a lot of thought into reducing the man hours and maching hours required, any way you can. For example; gear-driven accessories look neat , but it's a way more expensive method than belt driven ones and the method doesn't really offer a substantial advantage. Most big aero engines used a quill shaft or some other device to smooth out torsional vibrations to the accessory box and you'll probably need one too. The belts won't. Just one thought among many of simplifying things. Remember, Merlins were built by Rolls Royce with almost carte-blanche given to the designers to produce an absolute state of the art engine - not something even remotely economical or easy to produce. I once saw a figure for the parts count of a Merlin and it was staggering (15,000 or so??) So there is plenty of opportunity to simplify without resorting to crudity, I'm sure.

As for the demand for engine of 600 hp and up; if reasonably priced and proven examples were to appear, you can be sure airplane design would follow to make use of them. Airplane design is more often than not driven by engine availability.

How about this guy: http://www.falconerengines.com/bio/bio_v12.php

It’s a very well thought out engine, economy in the areas where mass produced parts will fit, and sound engineering in the others. After my current plane is finished, I’d love to build another around this engine.


Plunk down your cash, and concentrate on building the rest of your Mustang.

Good Luck!

PTAirco: That is true, the reason i went for gearing is for reliability more so then anything else. And the parts count will be alot less then a Merlin which i think is around 15,500ih.

Ive read the reliability reports on the Big block 572 for the S-51 and the issues with using belts for stuff. that is part of the reason i decided to go with gearing, that and the torque involved.


As for the CNC and machine stuff, i actually made some contacts and have been talking to a few people who have alot of machine tools. I believe that 80 or 90% of this engine can be made form sand castings. the only forges would be the cranks, connecting rods and pistons. The gears and propeller output shaft would be billeted. there is only about 6 gears in the gearbox, the crank, camshaft, injector pump magnetos, oil pump, the Starter is attached to the crankshaft, the Supercharger is also attached to the crankshaft via the camshaft.

Depending on what engine, a single or a two stage supercharger can be built in with a simple planetary gear set.

adburhoe: Those Falconers aren't that good. they have improved on their design since the days of the Thunder mustang, however they are still flawed engines.

I have studied their design carefully, and they are nothing special, and they are still high RPM engines.

The falconer cannot give me the horsepower and the torque i need reliability, and their supercharger project was also a failed project.

its only a 600cid engine, but it has issues withing its self that would make me think twice about flying in and airplane with that engine.

[quote=pepsi71ocean;43936]b
Depending on what engine, a single or a two stage supercharger can be built in with a simple planetary gear set.

/quote]

I assume it will be a centrifugal supercharger? Do you have a method of de-clutching the drive, like the Merlins centrifugal clutches? It will self destruct without some kind of clutch in there.