My unique mission and why the BH seems to fit

[f7ben]

Hi Ben,
The first thing that comes to mind when I read your plans is that they are very ambitious, and that your expectations are a little optimistic. Especially your expectations of build time and utility upon completion.
A first-time builder who completes a Bearhawk in a year and 1200-1500 hours of build time is an extreme outlier. Someone who does that is the one who builds from a quick-build kit and does not deviate at all from the basic configuration. He also spends extra money to buy bolt-on options whenever they are available, and does not spend time to customize or fabricate custom parts, or to scratch his head figuring anything out. Building in that time frame definitely does not involve a less-proven engine installation. A more realistic time frame for a first-time builder who does not significantly deviate is 1500-2500 hours, and a more realistic number for someone who installs an auto engine is 3000-5000. Sometimes we look at those numbers and thing "I'm smarter than the average bear, I can totally be on the short side of those hours." I've spent lots of time with lots of Bearhawk folks, and found that at least for me, this was definitely not the case.
As Jim says, many people have come before and said that auto engines <i>should</i> make so much more sense than the antiquated airplane engine technology. But yet, as Jim also says, the devil is in the details. Car manufactures have established spectacular reliability by investing decades of expensive R&D to the entire vehicle, not just to the engine. Making a car engine work in an airplane requires plucking one highly engineered part out of a highly engineered vehicle, and then highly engineering all of the dots that connect it to the airplane. For example, the engine mount, exhaust system, fuel delivery, PSRU (with the challenges that Jim points out), fuel metering, cooling system, cowling, and parameter monitoring. And all of this must not just be accomplished so that it works at all, it must work with extraordinary reliability, weigh as little as possible, and each component must fail in a way that it delivers an acceptable level of risk upon failure.
I'm of the opinion that traditional aero engines, while they seem antiquated and simple, are actually not very antiquated, and not at all simple. Get a copy of the Sky Ranch Engineering Manual by John Schwaner (<a href="http://amzn.to/2vPnKhC">Amazon link</a>) and read the whole thing. Read Kevin Cameron's books about the complexity of delivering the "shoulds" into actual performance. He writes a column in Cycle World magazine that is mostly about motorcycle engines, but he also talks about airplane engines, and talks alot about the kind of R&D it takes to realize that theories don't always translate into the expected performance. Reading his work changed the way I understood how engines work, and I haven't read but a small percentage of it.

To summarize, there have been Bearhawk builders who have successfully integrated auto engines. I know of one that has stuck with it (though there may be another) and when asked if he'd do it the same way next time, he said no. I have not yet met anyone who would recommend the auto engine to a future builder. There may be someone, but if there is, I have not yet heard from him.

Aside from the auto engine issue, which has also been further discussed in the archives, I'm afraid that you might also be over-estimating the utility of travel in a GA airplane. Have you started the cross-country part of your training yet? Taking a trip that long, that regularly, in a place that far north, is a big deal. If you are planning to fly VFR only, taking a 480nm trip is an adventure every time. By that I mean that you never really know how it is going to turn out until you do it, and if you have a rigid timeline to complete the trip, you'll either be regularly lucky or regularly disappointed. If it is time to go and the weather is bad, are you able to wait for a few days for it to get better? If you are planning to go IFR, how will you handle avoiding icing conditions in the months that aren't the summer, and the convective activity otherwise? Traveling in a light single engine plane is not like driving a car at 150 knots, combining the best of car travel and the best of air travel. Each mode comes with its own advantages and disadvantages. When someone travels by GA for fun, he usually has fun. When he travels by GA (talking about light singles) for utility, he finds that determination is not something that can overcome mother nature. (to that point, everyone should read "Finding Carla" by Ross Nixon <a href"http://amzn.to/2ihf4fb">Amazon link</a> )

I know this is a lot of negativity, and it isn't fun to have someone pee on your corn flakes. It's just that when I read your original post, I see red flags that indicate your expectations might not match your plans. Sort of like having a friend say "I'm headed to Florida!" then watching him pull onto the I40 onramp.

Hi Jared , thanks for taking the time to type that out. I appreciate that input and its why I joined here and intend to participate when I have something to ask or offer.

On your first points about build time I would totally anticipate that my goals might be a little optimistic or ambitious. But you basically did describe how I would intend to build. From a QB kit , very little custom modification or deviation from plans , I would certainly purchase any parts that are a better mousetrap or are prefabbed and available etc etc. I would also consider getting the project started in a builder assist program for a month or so working and paying for the time of an experienced professional. I want to be involved in all aspects of the QB through completion but I'm not too proud to hire experienced help if its an option. I also have several close friends who are A&P's and they are a phone call away.

On the issue of the Auto setups. Certainly my mind is not made up and I am open to all options. I would not purchase a setup that didnt have a mostly complete FWF package available. I'm not willing to be the guinea pig or do all the FWF design myself. It seems that Viking and also Aero-momentum either have things worked out completely for a lot of similar setups to the bearhawk or they are willing to do the design if you are the beta. I am totally comfortable with the ancillary systems surrounding the auto. Fuel system , cooling system , induction system etc and this work is right in my wheelhouse. I enjoy it and have some good experience in the area. The engine mount and cowling are really the only things I would need worked out and if the engine supplier cant help with these then its a no-go.

On the points concerning my plan to fly XC as my main mission I certainly may be off base on my expectations there. My schedule is such that I get can get 4-5 days off in a row several times per month. If the weather didnt look clear and optimal for flight for the trip then we would not go. If we made it to MN and the weather didnt look good for our departure then we would leave early or I would put in a few vacation days and stay until it cleared.....or I would just drive back. I am not willing to risk flying in adverse conditions aside from possibly some very light IMC if needed. I do plan to get my instrument rating and I think that from my research a lot of crashes are due to disorientation in inadvertent IMC flight. I won't make that mistake. The issue of icing scares the hell out of me. Although I think that it poses such an issue because I dont fully understand it or how common it is at this point. I would certainly avoid any potential icing like the plague.

I dont take your post as negative at all , just the opposite. To be honest I dont know any pilots ....I have very little exposure to it. I guess I just have the desire to make it a reality. I love working in my garage on stuff like this. Overall it would be my plan that adapts to reality and I wouldnt try to force the issue if things take longer or if I end up flying XC a little less then I would like because its just not realistic to make that flight every month or so.

[Mark Goldberg]

Hello Ben. I have been following your postings to the forum. If you have any questions about the QB kits, I am happy to help. Right now I am visiting the kit factory. Will be back in Texas Tuesday afternoon. Give a call to our toll free # which rings through to my cell phone if you would like to talk about the kits. Mark

[Bcone1381]

Ben;

I am also following your post. The best decision you have made is to go with the Bearhawk. I am building a Patrol from the QB Kit. Mark Goldberg is fabulous to work with. He responds quickly, and I have found the kit assembly easier than I anticipated. Builder support thru Mark enjoyable. You'll make a new friend I think. Its easy to get the questions answered that come up along the way. E-mail or phone calls to Mark are quickly answered...every time.

Brooks

[Mark Goldberg]

Thanks for your kind words Brooks. Although not entirely correct. As I said above I am visiting the kit factory now and for some reason my cell phone is not receiving calls. So I suspect there are at least a few calls going unanswered. Hopefully I can get in touch with people that have called when I return. Instead of going to my voice mail, callers are getting a message en Espanol that no one will understand. Mark

[f7ben]

Hi Brooks , where abouts in SE MI are you. I would love to get to take a look at a kit if you arent too far away and wouldnt mind showing it to me sometime.

Ben

[Bcone1381]

Ben,

I sent you a Personal Message.

[f7ben]

Hello Ben. I have been following your postings to the forum. If you have any questions about the QB kits, I am happy to help. Right now I am visiting the kit factory. Will be back in Texas Tuesday afternoon. Give a call to our toll free # which rings through to my cell phone if you would like to talk about the kits. Mark

Hi Mark , thanks for posting. When the time draws nearer to my decision on a kit and ultimately ordering I will be sure to call you and discuss the Bearhawk and the questions that are sure to arise over the coming months.

Thanks

[f7ben]

Forgot to add that my first flight training session is scheduled for next Tuesday and I opted to train in the 172 vs the 152 thinking that the 172 was a little closer to what I would like to own and operate. I've never been up in a small plane so this is all going to be a first for me. To say I am excited is an understatement.

[Bdflies]

Very exciting Ben! You're embarking on an adventure that most of us have experienced before you. I still remember my first lesson, in a C150, in 1974... I'd venture that most didn't have the vision of a purposeful mission, as you've described, but adventures evolved nonetheless. The pursuit of a pilot's license wasn't particularly easy or swift. It's something you do because you want it, or simply have to, because not flying is just not an option. Make no mistake; it's not a piece of cake! But I couldn't imagine not flying. Some do it for a living. Some do it as a hobby. The luckiest among us get paid to do what they do as a hobby!
And don't let us dampen your enthusiasm about alternative power plants! My personal toy car is a warmed over Mazdaspeed Miata, but our current family project is a 93 Supra Twin Turbo that'll make some amazing numbers. I'm with you about technology! Just be aware that alternative power is a pursuit that might dwarf the actual construction of the Bearhawk.
Please keep us informed as your adventure unfolds!

Bill

[Walley]

Ben, if you're serious about an auto conversion, I would look into Contact magazine (http://www.contactmagazine.com/). They only publish about once a year, but are focused entirely on experimental engines and you can order all the back issues or find ones specific to your plan. Good luck with your build

[Walley]

Ben, if you're serious about an auto conversion, I would look into Contact magazine (http://www.contactmagazine.com/). They only publish about once a year, but are focused entirely on experimental engines and you can order all the back issues or find ones specific to your plan. Good luck with your build

[schu]

Fellow sledder....nice. Electronic ignition and fuel injection make the aircraft motors more acceptable and if I do end up with an O-540 it would have EI and an SDS standalone driving it. The other issue I have is with the cost of these motors. I understand part of the issue is volume sales but you can buy 7 or 8 LS1s brand new for what one new underachieving Lycoming costs. That just strikes a chord with me that I find totally unacceptable. A good part of that is due to the bloated idiocy of the FAA and certified costs associated with their regulation

I see the Conti vs Lycosaur issue as merely a Ford vs Chevy thing. As far as PSRU's I think they are easily able to be engineered right if a company took the time to do it. Look at yamaha apex motors. They have gear reduction and that unit will take 500HP and dead hook launches off the ice. Same thing with the Diamond Drive on the turbo cats. 500HP all day long. The hydraulic CS prop is an issue but there are some very nice electric variable pitch setups and that is the way I will go. MT or Airmaster etc etc. Being an electrician I am much more comfy with those vs the hydraulic ones any way lol

Which Conti did you go with? Did you buy it as a functional core and do a complete overhaul?

Just saw this and yea, like others have pointed out, what you are proposing has been attempted by many many before you, and some are flying, others gave up and bolted up a lycoming, and others died.

To make my point more clear, I'll use the snowmobile analogy since that's something I've also spent some time with. What you are proposing is like buying a bulkhead, track, and sheets of aluminum that you fabricate into a tunnel, then building up a completely custom engine out of a motorcycle, retrofitting your own reduction unit, then sorting out all of your clutching, fuel, dropcase, cowling, and having it running well enough in one season that you are comfortable doing 3000ft face highmarks without failures, and you have never ridden a sled before.

Actually, what you are proposing is significantly more dangerous and complex, and the problem is you don't know what you don't know.

So lets start with auto engines and why they are a bad idea.

Any time you have an engine you have torsional vibration. The crankshaft accelerates and decelerates slightly every revolution as the pistons are generating and sucking power depending on where they are at in their stroke. The only thing that dampens torsional vibration is a large inertial mass that the engine is connected to. In a car or a truck this is the running gear, the tires, and the mass of the vehicle, which is a lot of inertial mass. In an airplane this is a propeller, which is basically a tuning fork. If you have the torsional vibration of the engine excite a harmonic of the prop, it's like taping a tuning fork at it's resonance frequency. It won't just come apart, it will absolutely self destruct, in a spectacular way.

When you add the complexity of a PSRU, this gets even more complex because you add in the harmonics and gear lash of the gearbox.

Now, if you know the engine, and the prop, and don't deviate, then you can do some harmonic testing to make sure you don't have vibration problems, but the second you change anything, the rods, the pistons, the prop, the cam, anything, you can suddenly find yourself back into the harmonic danger zone.

Most people that build PSRU's don't do harmonic testing, they just figure that they have a few hundred hours on the prototype and are good, but that doesn't mean anything as one person with a slightly different anything that operates at a slightly different cruise RPM can suddenly have catastrophic failure.

Go look through the NTSB at auto conversion accidents. You will find that it's almost never the auto engine that's the problem, it's the supporting systems. The electrical, or fuel, or PSRU, or prop that fails.

Even if you can figure all of this out, it WILL add 800 hours to your build in fabrication and testing and TEST piloting.

All of that said, the little 200hp engines you mentioned won't yard a bearhawk off of the water on floats very well. Trust me, it won't work. I could put a 300HP honda engine in my 8000lb truck, but it's not going to work like a cummins even if it's the same HP. Best case is that it will be running at 6000rpm tearing through the fuel wearing itself out trying to make it work. In an airplane it will blow up when you are 200 ft off the ground, which unless you are seriously paying attention will kill you.

My recommendation, buy a cessna 172, and start flying it until you are comfortable, then decide what you want to do. That's the snowmachine equivalent of telling someone to go buy a 600 and learn to ride before building up the custom monster that few people actually get to work right.

Speaking of sledding, one sled I built years ago was 190HP, and it was stupid fast, but getting the suspension to work right was difficult. Making 8000hp is one thing, but building a system that converts that into 3 second 1000ft laps is another story altogether. Engineering a complete solution is WAY more than just engine.

If you think gearboxes are not a big deal, go lookup the lycoming go 480 engine and how to make it survive:

http://republicseabee.com/Files/GO-480%20ops%20big.pdf

The only gearbox I would run is a rotax, and only because there isn't much deviation between setups, and they have millions of flight hours.

[schu]

Go grab a Cessna 172M with a o-320 engine. They are cheap to work on, can cover 480nm in just over 4 hours, and fuel consumption at 8000kt leaned is only around 8gph. It's very close to your requirements, only $40k for a nice one, and most of all, it's a very safe airplane.

Put a few hundred hours on that, then start on a bearhawk. When you are nearing completion, sell the cessna and that will pay for your engine, prop, and maybe even some of the panel depending on what you get.

[Battson]

Electronic ignition and fuel injection make the aircraft motors more acceptable and if I do end up with an O-540 it would have EI and an SDS standalone driving it. The other issue I have is with the cost of these motors. I understand part of the issue is volume sales but you can buy 7 or 8 LS1s brand new for what one new underachieving Lycoming costs. That just strikes a chord with me that I find totally unacceptable. A good part of that is due to the bloated idiocy of the FAA and certified costs associated with their regulation

I see the Conti vs Lycosaur issue as merely a Ford vs Chevy thing. As far as PSRU's I think they are easily able to be engineered right if a company took the time to do it. Look at yamaha apex motors. They have gear reduction and that unit will take 500HP and dead hook launches off the ice. Same thing with the Diamond Drive on the turbo cats. 500HP all day long. The hydraulic CS prop is an issue but there are some very nice electric variable pitch setups and that is the way I will go. MT or Airmaster etc etc. Being an electrician I am much more comfy with those vs the hydraulic ones any way lol

It's important to consider all the performance criteria placed upon an aircraft engine, before judging them.

I imagine if you tried running most any automotive engine at 75% of full power for 2,500 or 3,500 hours, with thousands of cycles from zero to extended full power runs in between, and with the vibration and stress of a propeller in turbulence attached to the front, you would not be impressed. Auto engines are designed a lot closer to their limits, and are designed to run in tightly controlled conditions. Because they normally run at much lower power settings and the consequences of failure are basically nil, this is a viable design choice.

I think that reliability is possibly the single biggest factor behind any aircraft power plant design. The consequences of failure are dire. When I am 60NM away from land or over rocky peaks behind my engine, the cost, power output, and efficiency are all secondary considerations.

What's more, ICE technology stagnated a long time ago. Things haven't changed in a material way for decades. Maybe aircraft engines just found their sweet-spot a little sooner because of the pressures of flight and limits of certification. If not for the marketing department and oil companies, I think there would be a lot more criticism levelled at "modern" ICEs. I agree that experimental ones can easily be improved a wee bit, but the margins aren't very big.

An afterthought on vibration and harmonics, I am not sure whether the PSRU reduces the risk there, maybe it does - I know there are a range of benefits of a PSRU. However, what I learned recently is there is no warning about incompatible prop-engine combinations. The vibration frequencies are so high that you can't even tell if there's a problem; until the prop or engine physically fails - normally a catastrophic failure - that's the first you learn about it, unless you do extensive factory testing. Of course wooden and composite props (like the MT) are not particularly vulnerable to this kind of harmonic or vibration failure.