V220 / V300T stillborn?

[rv6ejguy]

Originally Posted by Andy_RR

Ross,

Even after throwing all your technology at the engine, you are not going to make massive (i.e. convincing) inroads into weight, power, SFC, durability or cost. It's undeniable you will acheive some headline benefits in some areas and possibly even at least a small, but hard to measure benefit in all areas, but is it enough to create a quantum shift in the industry?



I take your point about targeting the non-certified market only, but whilst it keeps some costs under control, it doesn't eliminate liability in the US maket and it absolutely doesn't give you the volumes that viable amortization will need. Which ever way you crunch the numbers, you'll have to do it for the love of it rather than for profit - not a good way to start/run a business.

A

I already admitted in an earlier post that I didn't expect to make huge strides in SFC or weight over a Lycoming.

I think you underestimate the experimental market in North America. If you look at the numbers of kits being sold just from the big 5 or so, it is in the thousands per year. They all need engines.

Power to weight ratios on existing engines- remember the weight of accessories. Rotax installed weights are listed with all accessories. I figure an average O-360 with lightweight starter and alternator, mags, carb and harness is pushing close to 300 lbs. The 100 hp 912 has a slightly better power to weight ratio than a O-360. The O-235 is way heavier than a 912 or 914, Van's would have just used the O-235 in the RV12 if it was even close in power to weight ratio.

All this fear about integrated redrives seems unfounded. There have been hundreds of thousands of geared engines built over the last 60 years. Not a big deal in 2006.

[gmcjetpilot]

Originally Posted by rv6ejguy

I already admitted in an earlier post that I didn't expect to make huge strides in SFC or weight over a Lycoming.

The O-235 is way heavier than a 912 or 914, Van's would have just used the O-235 in the RV12 if it was even close in power to weight ratio.

All this fear about integrated redrives seems unfounded. There have been hundreds of thousands of geared engines built over the last 60 years. Not a big deal in 2006.

I agree. The 118 hp, O235 is 218 lbs (best est. dry) and the 115 hp 914 is 162 lbs (installed dry?). The ratios 0.54 and 0.71 hp/lb. That is definitely better by 24% and why the light weight LSA's almost have to use the Rotax. However in the higher HP Lycs the wt/hp ratio is more favorable. Assuming Rotax could be scaled up the power to weight advantage would be 6%. The IO340 ECI stroker has a 0.66 pwr/wt ratio.

Is weight a big deal? Depends on who you talk to and if your engine is heavier. I know the alternative engine guys down play that aspect of their installations weight. I think lighter is better and the Rotax lb for lb can more claimed power per lb on PAPER. Now it would be interesting to see what the real world performance is.

I know the "Kit Fox" guys have the Rotax 912/Continental option and they find the 100HP Continental O200 climbs better than the 100HP Rotax? I don't have the weight for the Continental, but the pwr/wt ratio for the 912 Rotax is about 0.71 hp/lb, exactly what I est for Lyc O235. Clearly the tubro on the rotax 914 increases efficiency.

I always said auto engine conversions (Subaru and Mazda) should be turbo-ed. It's as close to free lunch as you get, using wasted exhaust gas pressure and heat to get more work out of your fuel. The Mazda gets the most advantage from turbo charging because it waste energy out the pipes is high. The high velocity, high EGT waste is converted into work. I THINK the rotax 914 turbo owes most of its efficiency and pwr/wt ratio to the turbo, not super design. The gearing also does not hurt.

Again "gearing" and turbo charging are both magic when it comes to increasing power to weight. I also agree gears and turbos are not to be feared, but it is something else to go wrong or maintain (may be no big deal depending on the design). It's a design phylosopy. Clearly the engine should be designed with gearing and turbo charging in mind.

What does a O200 or IO240 Continental weigh?

[bumblebee]

At the risk of pulling back the curtain too far:

Originally Posted by rv6ejguy

This would be a very interesting project to be involved in. Examining the pros and cons of materials like MMC for the case, titanium rods, 2618, WMS-75 or 4032 for the pistons. Explore EN30B vs. 4340 vs. 5140 vs. nodular iron crank materials as have been so successful for GM with rolled fillets and nitrided surfaces. Plastics for the intake system, VCs etc. as used by most OEMs today, SPS type fasteners, sputtered anti friction and thermal coatings. Cryogenic stress relief vs. traditional methods. Carbon fiber gear housings. CFD modeling of the intake and exhaust flow and thermal loadings and flow. Tuned intake and exhaust systems. The list goes on.
I'd be like a kid in a candy store sorting through these details and cost vs. weight benefits.

Ross has come surprisingly close, with some minor exceptions, to describing a purpose-built aeroengine that is flying at this very moment. 100% designed from scratch from the crank on up. Recip. Air/liquid/oil cooled. No gearbox. No steel exc crank. No cockpit. RV powerband and size. several 000 hours w/o failure of any kind. 99%chance it'll never see commercial.

Auto-engine format is not necessarily the answer. VT220 was doomed from the start. Far too large/complex/heavy/costly. VT220 won't be the last one to RIP.

If it weren't for professional confidences (and binding NDA's), I could recite the status, engineering specs and likely future of every engine ever mentioned on this forum....including test results, tear-downs and props where applicable.

It's safe to say there will be a few surprises coming our way in the near future. Someone on the forum (not Ross) got lucky a while back and guessed an engine correctly without realizing it. (George will be frantically searching the archives to see if he can solve the riddle.....no clues from me).

FEA, CAD, RP, etc. are wonderful indespensible tools but in our experience, they serve mainly to produce more duds faster rather than the opposite--not necessarily a bad thing. Unless the design context is immensely sophisticated (modeling, testing, flow algorithms, probability matrices, etc.) a CAD/FEA engine stands only a slightly better chance than one designed on a slide rule. The TIME to failure is shorter, for sure .

Ross, George and Andy will appreciate this:
We use every SOTA (state of the art) tool available, yet I have 2 words for engineers who come to my office singing the praises of modern design tools as the holy grail:

Kelly Johnson.

His picture is on the wall right next to George Patton's. They are the only pictures up on the wall in the "chamber of horrors" aka Design Review.

Ross has the correct philosophy: small teams with good tools and open minds. However, when discussing entire platforms (i.e. entire engines) one needs enormous resources to bring those "small-team" designs successfully life in the shortest possible timeframe. Hyundai shipyard is a great example.

Requirements -> Design -> Build -> Test -> Lather -> Rinse -> Repeat as necessary.

[rv6ejguy]

Originally Posted by bumblebee

FEA, CAD, RP, etc. are wonderful indespensible tools but in our experience, they serve mainly to produce more duds faster rather than the opposite--not necessarily a bad thing. Unless the design context is immensely sophisticated (modeling, testing, flow algorithms, probability matrices, etc.) a CAD/FEA engine stands only a slightly better chance than one designed on a slide rule. The TIME to failure is shorter, for sure .

Well you certainly made me laugh!

Not to sound too negative but sounds like whoever you are working for is spinning its wheels in the formative stages of the concept not to mention the execution of the working design. Isn't engineering something supposed to lead to a successful conclusion? This sounds like what I was saying about waste.

Not to put a bend on the engineering profession as a whole but I have seen plenty of reasonable designs by non-engineers work and make it to the market, albeit with some flaws, while some big expensive projects with many engineers and too many micro managers at work, well awash in red ink before anything is even market ready. These die a quick death in most cases. I've seen stupid designs by both layman and engineers and I've certainly had my share of brain farts. Nobody has a corner on choosing the wrong solution path sometimes no matter how much formal education and money they might have.

We are involved with several projects from the FADEC side with the people behind them so worried that someone will steal their great ideas, the NDAs are almost the first topic of discussion. I hope a couple of these actually fly and stay in the market for people because they are pretty cool. Our experience in the past though is similar- less than half make it to market and less than half of those are a commercial, lasting success. I still cheer for all of them. Life is built on dreams, not doing the same old thing over and over.

Yep, my theoretical small team has one engineer to crunch the numbers and pick up what is not obvious. The rest are engine builders and machinists who get things done and work from vast past experiences with similar problems. They've probably seen it and solved it before. Then again, we might end up with something using the tried and proven- like the old Lycoming! The meeting room is the shop floor, not an office and no official beancounters are allowed in. Problem- poll for best solution- build it.

Do you enjoy your work? I couldn't work on projects that flop or are canceled on a regular basis, even for good money. Bad for brain health. I like to see my ideas fly- literally.

[the_other_dougreeves]

Originally Posted by gmcjetpilot

I agree. The 118 hp, O235 is 218 lbs (best est. dry) and the 115 hp 914 is 162 lbs (installed dry?). ...

I see the 914 for use in a very different mission than the O-235 / O-240. The beauty of the 914 is its ability to provide full power at altitude, where the O-235/240 are much simpler and much less high-strung. I see the 914 a great engine for use in a light airplane that will be used in / near the mountains. The RANS S-7 taildragger is such an example.

The 914 / RV-9 combo would be interesting, but since the cost of the O-320 is lower then the 914, it's a non-starter.

Originally Posted by gmcjetpilot

What does a O200 or IO240 Continental weigh?

Per Mattituck, their TMX O-200 is 215 lb and the O-240 is 240 lb.

[rv6ejguy]

The cost comparisons are interesting. While we are all shocked by a $18K kart engine built in quantities of hundreds per year, many people accept a $40K Lyco 540 price built probably in the hundreds per year and with tooling and development costs theoretically paid for decades ago over many thousands of engines. Granted there are more parts and materials in the Lyco but costs should have been amortized over the last 40 years.

The quantity of scale extends to something like a GM LS-2 engine which is more sophisticated than either in terms of technology and number of parts, built by the tens to hundreds of thousands per year at $5500 in crate form, about 10+ times cheaper than anything close in the aircraft world in this hp range.
This is the main reason for auto engine core bases for aircraft use, someone else has paid for the design, development, validation and production in mass quantities. It is impossible for a clean sheet design built in quantities of hundreds to thousands per year to come close to this price point. If the package weights can come down, a well executed package would be quite attractive for many.

Aircraft engines are like putting gas in your car for most people.They don't like the price but that is the price to having and airplane and using it. People will pay, even if pricing seems high. The price of an O-360 or clone would appear to be not all that unreasonable today considering what else is available and with liability costs tacked on. It is unfortunate that much of the liability costs incurred by Lycoming in the last few years has been due to poor management/ QC and outsourcing parts in a failed attempt to reduce pricing. They were producing pretty good engines up to the late '90s or so and should have left production processes intact. Lessons learned hopefully and to get back on track soon.

I agree with the views that the V220/ V300T engines were probably too complicated but the target market was probably wrong if costs were going to be spread out over larger quantities. This hp range market is far smaller than the 150-200hp range even though there is already competition there. You are totally dependent of picking up an OEM contract to make it a go and those are elusive for most new engine manufacturers.