V8 engine Cessna 172

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sming

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I believe he described in another thread the design of the ECU (or I have the wrong guy?) and it was pretty involved, with redundancy and software written almost from scratch for airplanes. Sounded like a substancial effort and different from the usual hidden megasquirt?
 

Victor Bravo

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Ok, now tell us about the regulatory situation. The FAA is not going to allow you to put 172 airframes under amateur built experimental. That leaves the other experimental category which is dubious and highly restricted.

Your FAQ addresses this, and I don't think you're gonna have long before they crack down on the obviously NON-exhibitional use of the aircraft. For a flying club do you think a vinyl decal satisfies the 'exhibition' part?

Also, putting an LS into an airplane with an aftermarket ECU? Great! You've advanced to the early 1990s!
There are two other experimental certificates he could qualify for, R&D and Market Research. Both would be 100% legit in this situation.

Going from the mid 1930's to the early 1990's is a pretty big jump in efficiency as far as I can see.

He could have tried to get all the way into the 2000's, and use the engine off of the Raptor, but we see how that's working out.

He could get all the way into the 2020's and try to use batteries, which would work just fine except for being the world's first single-seat limited Cessna 172.
 

Hephaestus

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I for one applaud the work...

Look at the 100LL discussions; here's an engine that'll run fine on mogas. Look forward to further developments - the Republic seabee has an LS1 320hp STC available... So clearly there is possibility of getting there if you can get the FAA documentation in order.
 

Turd Ferguson

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Ok, now tell us about the regulatory situation. The FAA is not going to allow you to put 172 airframes under amateur built experimental. That leaves the other experimental category which is dubious and highly restricted.
The aircraft owner/operator will be responsible for obtaining the proper airworthiness certificate for the airplane. I think I would apply for an air racing airworthiness certificate and enter in one of the various air racing events every yr. In addition the the "NR" n-number, bright paint scheme that looks fast even when the plane is parked, some cool race numbers and complement of manufacturer and vendor decals, full on NASCAR style. All other flights will fall under crew proficiency and training.
 

galapoola

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I wonder how Draco did it? If I recall, he designed a new main wing and of course swapped a round engine for a PW turbine. Must be a balancing act, how much of the certified plane do you need to swap out to call it an experimental?
 

Victor Bravo

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Let me expand a little further on what I posted previously. If a reasonably well done and safe 250-260HP C-182 conversion were done using this as the base engine, you would wind up with a real four seat airplane that can climb safely and use unleaded fuel. Even if you knocked the TBO down to 1000 hours instead of the 1500-1800 for the C and L engines, you'd have something that is viable and realistic to use as a "real airplane" in the real environment.

Not to mention single lever control, and possibly an emergency 5 minute power setting to get you out of mountain downdrafts when necessary.
 

Turd Ferguson

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Must be a balancing act, how much of the certified plane do you need to swap out to call it an experimental?
You don't have to swap anything. Can get an experimental airworthiness cert. for any plane, including a factory original Cessna 172 but it won't be an experimental amateur-built, which is what most people think when they hear experimental. Draco airworthiness cert. was experimental exhibition, same as the Corsair V8 Cessna.
 

rv7charlie

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Pretty sure it was exp exhib before he did any mods; that is a European design without a US type cert. Same as most warbirds, etc.
 

TLAR

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I suggest that some of you brush up on your reading comprehension skills.
 

J Galt

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Again, good on you for doing it. There's always some Negative Nancy who want to try to chip away at another's accomplishment, even here on a site for doing experimental things. Don't let them get you down.
Justin
 

mcrae0104

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Ok, now tell us about the regulatory situation. The FAA is not going to allow you to put 172 airframes under amateur built experimental.
According to corsairpower.com, "Corsair is seeking FAA STC certification as a replacement engine for certified airframes..."
 

skydawg

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Thanks for the encouraging comments, its motivating & much appreciated.

As for those more critical RE experimental limitations: Your understanding of experimental limitations is wrong and outdated. Experimental op limits were re-written years ago that remove most of the restrictive op limitations for the exhibitions category, and became nationwide policy rather than subjective to individual FSDO's (although local FSDO can place additional limits for extraordinary locations or circumstances). These limitation are clearly listed in FAA policy 8013 and for a class 1 aircraft as a single engine piston, they are near identical to amateur built op limitations. The Corsair C172 holds a multi purpose AC, including exhibition category, which places no geo limits on post phase 1 maintenance of proficiency flying, for example. Additionally, FAA policy (ref FAA order 8130.2j) allows flight training in experimentals as long as no compensation is received for aircraft. Moreover, an experimental flight club is indeed permitted as long as structure is members own part of the aircraft and reasonable fees are paid. With FAA changing LSA rules to allow up to 6 seaters, this makes the certification argument moot. Regardless, putting a certified in EXP is not as limiting as yesteryear.

Again, a lot has changed in the last 10 years RE EXP op limits, kudos to EAA and warbird associations advocating. Our program took considerable time being accepted by FAA and we had to provide many technical documents and procedures; which we abide by.

As far as using an outdated ECM form the 1990's: This ECM was in production form 2008, and still produced today. We did not use the latest because its easier to demonstrate reliability/service history with older unit. It is by no means tech from the 1990's; it has been updated/improved over the last 15 years to correct issues seen in hundreds of millions of vehicles worldwide operating many different conditions.. Although there are newer units we considered with more bells and whistles, these would need years to reach the number of units in use to statistically show reliability and work out bugs.

As far as some of your questions go, the posted video was at 2,450'ish GW gross weight; there was a backseat photographer you can see on tail camera) and about 200 pounds led ballast (all flying is done at/near MGW, minimum oil levels, low octane ethanol fuel). We routinely change software settings to include different max HP for different reasons. The C172 was certified up to 220 HP so we stick to that max limit. In this video, HP limit was set at 210 HP +/-5. Because the engine is so flat rated below its capability, it can maintain that limit to above 6k ft , whereas stock c172 engines HP decrease as soon as you leave sea level conditions......so, a 180 HP stock C172 Lycoming, will be closer to 150-160 HP @ 8k ft.

The tachometer is engine RPM, not prop.

The ECM system is our design using DELPHI hardware. We developed our own calibrations specific to a redundant aircraft mission with help of engineering firm GM used on the exact hardware (we had a lot of issues making automotive controllers work for the mission). We selected it for a number of reasons and after testing other types. Most did not have the hardware capability of using a mechanical throttle control, ability to work in tandem with 2nd ECM, multiple layers of practical redundancies, ability to program automatically switch control to other ECM with failures, lack of watch dog functions, ect...

We have tried to keep the website FAQ up to date with more tech info. Early on, we shared much of our designs on line for others to reference (and learn form our mistakes mostly), but legal beagles strongly recommended we take it down as we could likely be held liable should someone use the info and crash.

Again, thanks for the encouraging feed back. The plane is great to fly and we are putting more hours on it under stressful conditions, routinely taking oil samples and performing wear inspections. We have spoken with interested investor groups to develop STC (even though it was written above this would be impossible, the project already was issued a FAA G1 issue paper), but have not found any that share our vision. If we don't, will likely keep it as a toy and I would like to install the engine on something like a C210 with a MT electric prop.
 

Pops

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I know its a lot of work and money, but I hope you can keep the cost of the STC down where you will have great amount of sales.
Win-Win.
 

Hot Wings

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We have spoken with interested investor groups to develop STC << >> , but have not found any that share our vision.
:(
Hope this changes for you. If it does keep C175 owners in mind too.

If they do change the LSA rules then full certification under ASTM standards becomes a viable option. That might sweeten the pot for investors?
 

rv7charlie

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Skydawg,

I'm excited to see a group doing what you're doing, that appears to have the engineering background to create a truly functional package. I do believe that with today's automotive tech quality, there's no reason that 'mass market' engines like this can't be great a/c engines, and help drive down the biggest single expense in an a/c. I have no doubt that your system can 'just work', especially derated as much as it is vs the automotive application.

My only question, as I mentioned earlier, is the fuel flow & rpm shown in the video vs the HP numbers mentioned. There are hundreds of published dyno graphs on various LS motors, and depending on how they're cammed, they all make somewhere around 200 HP in the 2700-3000 rpm range, *at sea level MAP*. And while BSFC numbers on published dyno charts are less common, they're typically going to show .4-.45 BSFC. If we use the 210 HP number for climbout and ~11.5 GPH for fuel flow, that yields a .33 BSFC, which would have to be some sort of record for a spark ignition gasoline engine. Now if we assume that the core engine is performing like a 'typical' LS3, then the 210 HP at sea level would be at ~75% power (~158 HP) with the MAP available up at ~8000 feet density altitude, which, at a more realistic .4 BSFC, would give us pretty close to the fuel flow shown in the video.

Please understand that I am *not* criticizing your achievement. I want one! If I could find a suitable C210 size airframe, I'd buy it, assuming I could afford it, and the family CFO would release the funds. I'm bringing it up because I'd hate to see a great idea disappear because a calibration error or math error made it look like unrealistic claims were being made.

My other 'unsolicited' thought is about certification. I've been planning/installing a Mazda rotary for a couple of decades, and all the rotary a/c guys watched the Swiss company Mistral for years, as they developed their 2 rotor and 3 rotor a/c engines. Some of the rotary guys begged them for years to sell their reduction drive, and intake system to homebuilders, but with only a couple of exceptions, they refused, because they were so focused on the certified market. After investing many millions in development, they ran into the same problems you're seeing: investors just aren't interested because they know the old saw about how to make a small fortune in aviation. If Mistral had been willing to work with homebuilders from the start, they might well have been able to continue funding development and eventually reached certification/production. There are corollary examples, but I hope you see the point.

Again, congrats on what looks like a great design. Sell to homebuilders!

Charlie
 
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