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skydawg

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Jul 26, 2016
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Denver, Colorado
Hello Fellow Experimenters

We are completing development on a new piston engine product line for aircraft up to 350 HP for experimental aircraft. The engine uses an aluminum V8 marine engine foundation, modified for the aircraft mission. The engine is controlled by a redundant electronic fuel injection system and other engineered components to meet FAA part 33 and 23 standards. The engine controller is software controlled and can be quickly programmed to meet optimum performance for multiple aircraft types, weights, and prop designs. We use a blank GM Delphi ECM we source directly that is without any automotive programming; we developed our own aircraft mission specific calibration files using the same engineering firms GM uses. Additionally, the engine controller can wirelessly connect to our service app that not only allows quick and precise troubleshooting and tuning, but can be connected by WIFI for remote tuning and escalated diagnosis by our technicians if needed.

The engine is matched to a PSRU (optional) with several different gear ratios available. It is clutch-less, low maintenance and has chip detector monitored by the ECM. Each engine, PSRU and prop combo is tested by vibration analysis and by finite element analysis for structural requirements to part 23 standards. A digital engine display can be customized to display over 50 engine parameters, even fuel consumed or fuel levels. Additionally, the display monitors over 75 parameters and will annunciate an alert when any programmed levels are exceeded. Each alert indicates description of issue and specific trouble code until acknowledged by pilot. Each fault remains in the maintenance page with further info such as time stamp and specific service manual reference and troubleshooting tree.

The engine is flex fuel rated, so can consume several gasoline types, including AVGAS. Real flight performance numbers indicate it is more than 20% efficient (fuel flow vs. TAS), and cost 60% less to operate than O-360 legacy engines. Our C172 test aircraft operates for less than $19/hr compared to over $60/hr with original engine, while still far exceeding stock performance.

We would like to seek some input from the experimental community on what features are most important for such an experimental crate engine product, and gauge level of interest within the experimental market. We realize most auto conversions are home -grown, and many have negative perceptions of them for a number of reasons, so looking forward to gauging how many experimenters may see value in a more developed conversion and their suggestions of what features, capabilities and price point it should have.

Covid has left us about 4 months behind on C172 and C182 flight testing program, but anticipate product will be launched by next summer, and experimental crate engine soon after. Additional info can be found on www.corsairpower.com

I will monitor this thread regularly and look forward to hearing your thoughts/advice/ and ideas.

Thanks for any input. Fly safe.
 

rv7charlie

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Nov 17, 2014
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Hi,

I'm happy to see someone approaching this with science and engineering based methodology. I also like the fact that you're both using a proven, highly developed piece of hardware for the controller, and that it has zero automotive code in it. And if I've read other posts correctly, that it's redundant. Controllers are almost totally bulletproof these days, but 'traditional' fuel & spark delivery methods tend to fail more 'gracefully'. Same kind of thoughts on the reduction system. I'm really happy to see that powerplant being used (if I'm right about which one).

Now, for the ugly parts...

It really sounds like y'all are doing your homework, and it sounds like it should be a solid package. Unfortunately, it also sounds (justifiably) pretty expensive, and if that's true, it may be a tough sell to the experimental crowd. Looking at history, the Powersport rotary (2nd ownership) went through similar problems. They had a rock solid reduction drive, a rock solid core engine, and installed weight well under a comparable Lycoming (almost unheard of with an alt engine), and initially, a 'tolerable' and safe fuel delivery system. They never sold many systems, and I firmly believe that it was because their price at the time was equal to a new Lycoming of the same HP. We call ourselves experimenters, but very few of us really are; most of us are assemblers. Most of us can't bring ourselves to pay Lyc money for, let's face it, an unproven engine package. The Powersport package outperformed Lycs consistently in side-by-side tests, but the vast majority of potential purchasers just wouldn't roll the dice when they could have a known-quantity (and be in the air much faster) with a Lyc. With your HP range, unfortunately, in the experimental market you'll largely be competing with IO360s. There are very few homebuilts that can safely handle the weight/HP of a 300+ HP motor, and the ones that can are so expensive that the builder/owner probably isn't phased by the price of a 6 cyl Lyc. The guys who can both pay for it and are willing to risk a mid-6 figure airframe on a truly experimental engine are likely to be rare.

Or I could be wrong about the price. Am I?

The other thought I'd have, if history can teach us anything, is that while certification may be a noble goal (designing to that standard certainly is), it may by a hole that you can never climb out of, unless your financial benefactor has billionaire sized pockets. Example (again from the rotary world): the Swiss company Mistral. Like Powersport, they had a rock solid package. But they were totally focused on certification, and were unyielding in their refusal to sell in the experimental market, and refused to sell any of their individual components (gearbox, controller, manifolds, etc), either. If they'd been willing to sell to experimenters, they almost certainly could have funded certification out of experimental sales. The actual development work was already done and proven to themselves, but the grind of certification sucked the company's resources dry.

A last example, from the certified world. LoPresti wanted to build the Swift Fury, based on the original Globe Swift. The type cert was available to him; the Swift Association owns it and were ready to license it to him. There were close to 200 buyers ready to write a check for a new a/c, which he could have built and sold under the original type certificate with just a few of the dozens of existing STCs (sliding canopy, sticks, and either Cont or Lyc IO360). But he'd built his 'dream' version (which really was awesome), and it had so many changes that it would have effectively required a new type cert to get all the mods past the FAA. He refused to build anything but that, and the plane never happened. Again, he could have funded certifying the Fury by building 200 on the original type certificate.

If you sell to those of us who experiment, consider making your designs, not necessarily 'open source', but open enough to give the engineers among us confidence as they look at the designs. Show us how torsional resonance issues are handled. Give us actual peak torque numbers for the gearbox; show us the test data. Show us how you do switching between controllers; relays to sensors/injectors/coils? Duplicate everything? Etc. And give us confidence that we won't be the ones testing each iteration of the gearbox or controller (and paying for the 'fix'), as has happened over and over (and is apparently still happening) with a certain Subaru/Honda modifier.

Will you be willing to sell individual components (gearbox, controller, etc)? It'll kill you from a support standpoint, but if the designs are solid, it could help make your reputation.

Ok, I'm tired of thinking for the day. You've probably already thought of everything I've written, but maybe there's something buried in there that could be useful.

Charlie
 

Jimstix

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LAS CRUCES NM
First of all, good luck (sincerely). Next under-promise and over-deliver on schedule, cost, and performance. PSRU's are generally an engineering pain in the ass, so plan for that. Put these engines in as many types of aircraft as you can as soon as you can. I suggest that you keep an engine on the test stand running as much as you can to establish a fleet leader. Jim
 

BBerson

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Port Townsend WA
The engine is matched to a PSRU (optional)
Does that mean direct drive? It would more closely match the lower power range of a common O-320.
Other than that, I can't imagine GM involved in selling crate engines for aviation use.
 

TFF

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Memphis, TN
Homebuilt or certified, you have to have a 100% bolt on setup for certain airplanes, for a start. 100% including bolt on cowl, motor mount; every detail. There are plenty who can write the check, but they have no imagination on how to implement such a project. You have to come up with a sexy cowl. Sex sells, it has to look cool. You will need to target a couple of designs like RV10 and Bearhawk. Once there is a standard of installation, people will branch out and not need as much help on installing it on other designs.
 

WonderousMountain

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Clatsop, Or
Actually was thinking of this earlier,
You should totally consider doing a
V - Cowling, to match your engine.
Also consider a Thunder Hump 🤔. (Search function)
 

Tiger Tim

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Neat project, and I echo what was already said about making as simple a bolt-on kit as you possibly can for a handful of already popular airplanes.

PSRU... has chip detector monitored by the ECM
What does the ECM do with that information? Log it, light an annunciator, change operating parameters in some way, restrict max power output?
 

rv6ejguy

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The engine is flex fuel rated, so can consume several gasoline types, including AVGAS. Real flight performance numbers indicate it is more than 20% efficient (fuel flow vs. TAS), and cost 60% less to operate than O-360 legacy engines. Our C172 test aircraft operates for less than $19/hr compared to over $60/hr with original engine, while still far exceeding stock performance.
Cool project.

20% less fuel burn yet 60% lower operating costs? What did you include in calculating the operating costs of the 360 here? Was the 360 operated LOP in cruise when comparing to your engine? An IO-360 running LOP is around .42 BSFC. 20% better would put your engine at .346 which is better than certified light diesels.

Edit: I looked at your website on the overall operating costs and your chart is comparing to to the very expensive CD-155 diesel and electric options which don't even exist. I'd suggest comparing to the real competition which is the 360/540 Lycomings and 360/550 Contis.

Has your engine demonstrated a 3000 hour TBO in flight use? How many flight hours on the high time engine?

Weight compared to 360?

What is the target market?
 
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Victor Bravo

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I have an immediate testing and fleet data acquisition case for you. I believe this would be very valuable in terms of building a data-based case for certification.

I am aware of an Australian glider club that installed a V8 conversion in their Pawnee towplane. The towplane was operated in an incredible "torture test" duty cycle towing gliders for a busy glider operation. Far more harsh than even agricultural airplanes.

The engine demonstrated enormous savings in fuel and overall cost, maintenance, operational reliability, etc. One of our HBA members (and a member of my home EAA chapter) MM4440 is very familiar with this Australian demonstration, and is the president of the ESA homebuilt glider group.

He and I are both in a position to make introductions to a busy glider operation here in California, which happens to be the location for the Air Force test pilot school glider and spin training program. And several of their tow pilots happen to be off-duty Air Force folks from KEDW :) That kind of test program could provide you with a good opportunity to test and validate your engines in direct service with a commercial operation, under a Limited airworthiness certificate, and get a huge amount of useful data back (data acquired by people whose qualifications would carry real weight with the FAA).

Let me know if any of this seems interesting to you, and I will be happy to help.
 

rv7charlie

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Ross,

To be fair, he did say 'O360', not IO360. And to be more fair, lean of peak operation of a/c engines is still a niche field; all the guys you know may do it, but it just isn't wide spread across the fleet. And to be even more fair, it is a 300+ HP engine (even though it's likely dialed back a lot in a C172). A much more fair comparison would be the O470 typical in C182s (and much more sensible replacement). There's a good chance that the V8 could have lower installed weight; the 470 is pretty heavy.
 

rv6ejguy

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Ross,

To be fair, he did say 'O360', not IO360. And to be more fair, lean of peak operation of a/c engines is still a niche field; all the guys you know may do it, but it just isn't wide spread across the fleet. And to be even more fair, it is a 300+ HP engine (even though it's likely dialed back a lot in a C172). A much more fair comparison would be the O470 typical in C182s (and much more sensible replacement). There's a good chance that the V8 could have lower installed weight; the 470 is pretty heavy.
Just asking questions here Charlie.

LOP is not some niche field. At least 75% of my customers use it regularly as well as thousands of others with mechanical FI and even some carb guys with a dose of carb heat.

Not many folks fitting 470s any more. 550s are similar weight and more powerful. Let's not compare this engine with REALLY ancient technology. No way this package weighs less than a 470 which are around 400-430 pounds dry and certainly nowhere near a 360 Lyc.
 
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rv7charlie

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*I* use it. And I'm not surprised that 75% of your customers use it. But if you add up *all* your customers, what's that, as a percentage of the GA fleet, or even the homebuilt fleet? Don't let the tree you're in blind you to the forest. :) And remember, they're targeting certified GA, as well as homebuilts. There are still a *lot* of O470s still flying around, and FWF weight goes way north of 500 lbs on most. What we haven't heard yet is the price delta between the new production 540/550 a/c engines and this V8.

I did say in my 1st post that they'll likely be competing against 360s, and that it will be tough. There's the obvious weight penalty, and again, we don't know price yet.
 

rv6ejguy

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*I* use it. And I'm not surprised that 75% of your customers use it. But if you add up *all* your customers, what's that, as a percentage of the GA fleet, or even the homebuilt fleet? Don't let the tree you're in blind you to the forest. :) And remember, they're targeting certified GA, as well as homebuilts. There are still a *lot* of O470s still flying around, and FWF weight goes way north of 500 lbs on most. What we haven't heard yet is the price delta between the new production 540/550 a/c engines and this V8.

I did say in my 1st post that they'll likely be competing against 360s, and that it will be tough. There's the obvious weight penalty, and again, we don't know price yet.
If you step over to the Lancair, Bonanza, Cirrus groups etc., you see lots of discussion on LOP use. Anyone who's followed GAMI and the articles by John Deakin and Mike Busch for the last 20 years is probably a convert. I have to believe that's thousands of pilots worldwide. The widespread use of glass engine monitors today gives people the tools to do LOP properly.

We do know the price. If you checked their site, price is listed as $41,500.

Average price of 100LL in the US this month $4.56/ gal X 7.9 gph= $36/hr. just for fuel cost. AirNav: Fuel Price Report
 
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rv7charlie

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Thanks for letting me know the price was there; finally found it.

Skydawg,

That triggers some advice. ;-)
The 'Economics' page really does bury the price; at least it did for me. I was looking for a button like, 'How to Purchase', etc. And while a 'turn key' price is a good thing, it does make the engine look more expensive than it would be if bought as a 'crate' FWF package, (roughly on par with a new IO390 from Van's, with their OEM discount). It's noticeably cheaper than the 6 cyl Lycs, where it would be a better matchup, anyway. As Ross points out, comparing it to a new diesel installation is barely relevant. Comparing to a 6cyl engine replacement in a C182 should look very favorable to the V8, and be a lot more realistic. The V8 in a 172 is going to eat up a huge percentage of useful load.

There are inconsistencies on the Economics page. There seems to be 3 different fuel burns listed for the engine on the same page. While I don't doubt that the V8 fuel burn will equal or better an a/c engine at the same speeds in the same airfame (as long as cooling is done right), I suspect that most C172 drivers pull way back in cruise because it just doesn't do any good to waste the gas to go 2mph faster. Hence the commonly heard '6.5 GPH at 75%'; any fuel flow they're comfortable with is 75%. Perhaps publishing extremely low fuel burn numbers works for marketing, but I see web pages like this all the time that claim both high power numbers and crazily low (impossible) fuel burn at anything like normal 65-75% cruise power, and it kills their credibility with me. It's not always done to be deceptive, but it leads me to question either their ethics, or their basic understanding of physics & engineering. So, spell out *all* conditions under which the measurements were made. Transparency, as I mentioned earlier.
 

Dana

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An O-360 replacement doesn't interest me, but an O-320 replacement at a lower price point with the same FWF weight and propeller RPM would...

A crankshaft and/or redrive suitable for aerobatics and inverted systems would interest people, too.
 

skydawg

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Thanks for the constructive feed back so far.

To answer some of the efficiency questions, on the C172 test aircraft, we have some detailed data which shows the V8 is about 13% more efficient at lower altitudes, to 24% above 8k-10K feet. This really depends on prop, and we are still trying to make a quieter design. AS far as comparisons with stock C172 fuel flows and LOP techniques (which have been opined since I leaned to fly in the 80's), we simply use original C172 POH numbers per their published leaning procedure; we also have our V8 tuned slightly on the rich side for a few different reasons, about 13.9 to 14.4 AFR. This will be leaned a bit after more flight testing data in warmer temps.

Cost: for the certified kit, we are targeting about what it would cost to reman original engine with selling in the original engine to a overhaul facility we partner with . For the C172, original running engines yield $8-14K. Our target cost for complete kit (new engine, gear box, prop, and all other parts is about $38K for experimental only.... STC version will be much higher in US due to liability cost (you wouldn't believe the liability quotes). For experimental only, it will be less, but wont know until we have solidified the design, final weights and finished testing.

The V8 is indeed better suited for o470 and o540 air frames, and working on a C182 kit. Next year will be looking at some older twins that may work. We expect V8 to be even more efficient as a replacement for these larger engines.

As far as comments RE cockpit controls, besides eliminating the carb heat and mixture control, everything is the same. The throttle control is original and connects to a manual throttle body with redundant TPS sensors (we tried using typical throttle by wire throttle body wherein in throttle sends electrical signal to a servo, but it continued to fail when subjected to fault testing matrix). My background includes being a DER flight test pilot (albeit for transport category aircraft, but have considerable GA experience) and control layout was a pet peeve, so yes, the controls will stay in normal location.

RE comment of redundant everything, this typically adds more points of potential failures. We did a lot of testing on what was worth adding redundancy and what was not. Its more of a mathematical exercise than practical, factoring in mean failure rates, service histories, documented reasons for component failures, ect; then calculating what had to be added to have said redundancy and that added potential failure rate, ect. ect. The engine is rock solid, especially with it being so de-rated/flat rated, so failures were far more likely in the components, and this is where the critical components were added if it didn't increase potential issues (adding more connectors and wiring, adding more possible electrical faults, ect). The custom ECM calibration took care of many potential faults. So, more isn't always better. Toyota found this out when they FAA certified their piston engine; they calculated all the added stuff to meet FARs actually decreased the reliability, and cancelled the product line (for this reason, as well as liability and FAA mumbo jumbo). So, more isn't always better, especially with a modern mass-produced engine.

RE open source of software: this is a tricky thing because, as we well found out many times over, changing 1 little thing can affect so many other things, and it may not manifest itself until several other elements perfectly align, even if a DO178 analysis was conducted. So, changing some air/fuel ratios in a table is one thing, but changing basic calibrations can have dire consequences. Case in point, the ECM uses watch dog resets (essentially, if specific software operations hang-up, the feature can reboot just that portion of the programming rather than the entire operation) allowing the engine to continue running. We made a few small mods to add default values to the backup manifold sensor, which later caused another critical sensor's watch dog to continuously loop. These are sophisticated computers designed to be very stable when properly programmed to a specific operation and tested, and the reason a DO178 analysis is required for certification. The engineers that program these things have graduate degrees in software and computer engineering and extensive experience for the OEM's with the exact ECM models we use, and caution us about letting any manipulation of the programming beyond basic tuning unless another safety analysis is performed (which can be expensive).

RE focusing on certification: The project already has FAA G1 issue paper for STC certification, but we believe the experimental market may be a good proving ground if the price point works; we are not sure how many builders will pay for a conversion rather than save money by building their own. Also, most AB aircraft don't need such power. However, for the average builder to build this tier of one-off engine, it would cost far more than buying ours- many simply uses stock car engines, maybe get some ECM tuning to disable VAT and limp modes in the ECM ; so curious if many will see the value in a more production product.

RE proving ground on sail plane towers: Sound great, but believe aircraft would have to placed in restricted category, which may be tricky depending on FSDO or MIDO. I will PM you. Thanks.

Again, thanks for the input, please keep it coming.

-
 

Voidhawk9

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Seems to me that most experimenters willing to step out and take the chance on a new 'unproven' engine are also very price-sensitive.
You may need to get a bunch of engines out there operating in the wild at a steep discount (beta-testers?) to build experience and credibility before those with bigger budgets take you seriously. Make the deal compelling, and you'll get noticed. Write into the sales agreement that you can use their installs and aircraft as part of marketing going forward too? Photos of a C-172 flying it with no cowl will only get you so far; photos of 50 different aircraft of various types on the other hand...
I do seriously like the look of your product, though, and wish you much success! We need engines like this to become popular and widely accepted.
I'm looking at something like this when the time comes to bolt-on an engine in a couple of years, so I'll be watching closely.
 

PTAirco

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I admire anyone delving into the new aircraft engine market and wish you luck.

While I appreciate technology as much as the next guy, for the average homebuilt airplane builder there are only two considerations: cost and reliability (and possibly weight.) Your project sounds like it would cost, what - $50,000 or more a piece? If you walk down the line at Oshkosh there are plenty of of airplane owners that can afford that, but for every one of those there must be 100 (500? 1000?) who can't.

Reliability is something to be proven, so there is no point in speculating on that at this stage.

I'd be happy to bolt an OX5 on my airplane if it was cheap and reliable, even if it burns a bit more fuel. I do not need to sit there and watch 50 engine performance parameter displayed on a fancy monitor either.

The final requirement most of us have is: It actually has to materialize in our lifetime. Not like Deltahawk or Zoche, for example.
 
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