Mail Sack: Builder Questions #2 Panther Engine

Builders,

Here is the second of a new series, where I take actual letters from builders and answer the questions here, where the answers can serve many builders. Because the writers sent in the questions as private email, I have trimmed their name off the email to respect their privacy. Their questions are in blue, I put the answer in black. You can click on the colored links in the answers to read stories with longer explanations.

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Mr. Wynne,

I have on order from SPA a full LSA Panther kit.  I don’t have an engine.  To
save you some time I will list my current questions and then write my general
palaver. What are the details of your next Corvair College in MO?  Cost?  What must I
bring?  Is a core needed or can I buy it from you?

CC#30 will be in September in Mexico MO, at the Zenith Factory. The cost will be about $79, this will cover food and drinks for 3 days. The learning is free. We will have the registration page up in another week or so. You don’t have to bring anything, you can just come and observe. If you wish to assemble an engine, there is much prep work you must do in advance, the task is too big to just start with a greasy core on day one and finish with an engine on day 3. However, you can fully assemble an engine and run it from a collection of prepped parts, and have a good understanding of that engine, in three days. The best spot to learn a lot more about colleges in general is here: Corvair College reference page

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What do you think of the Aeroinjector?  I intend to fly Sportsman and possibly
Intermediate IAC aerobatics.

There have been thousands of hours flown on Corvairs with Aerocarbs, the red flat side predecessor to the Aeroinjector. There are reasons why they have their fans, but It is not a carb I would choose for a Corvair, and I would never run one in a fuel system with a pump. I know it can be done, but that doesn’t mean I would choose to. To learn more about carbs look at: Carburetor Reference page. Dan’s panther runs an MA3-SPA and he performs a lot of aerobatics with it. If you wanted to move up one level, look at a Rotec carb or an Ellison EFS-3A. The Ellison is now out of production. (After 30 years and thousands of carbs, Ben Elison perhaps has gotten a little tired of homebuilders who don’t read instruction and ‘experts’ on his products who have never used one) You have to speak with Dan, but his original plan was to use a precision mechanical injector for advanced work. see a picture below and read more at this link:Mechanical Fuel Injection Testing.

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I have been reading your websites.  You have a wealth of information and, you
obviously, have a masterful level of skill and knowledge.  You and Dan give a
lot of creditability to using a Corvair engine.

Thank you. I remind people if you do something for 25 years, you have a good opportunity to become very good at it, especially if the job involves teaching it to other people.

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My personal experience comes from a 1/3 ownership of a Cessna 172 and a Bellanca
Citabria 7KCAB.  Both had Lycoming O-320 engines.  Of course, the Citabria was
fuel injected.  Both engines ran without problem given regular oil changes,
compression checks, and general TLC from all 3 owners.  That gives me a base of
confidence in Lycoming engines.  So an obvious choice, for me, in an LSA
aircraft for aerobatic use would be a Lycoming IO-233.  The problem is that
Lycoming is not very forthcoming with information about this engine.  Also, the
nearest that I can tell is that a new engine would cost me over $30,000.  That
gives me the impression that Lycoming doesn’t want to service the LSA Homebuilt
market.

I have seen a 233, and it is impressive. It is not as light as the promoters suggest, but that is true of most engines and airframes in experimental aviation. ( A standard 10% error is what I call CBW- calibrated brochure weight, which is the actual weight multiplied by .9 for marketing purposes) You are correct, Lycoming, and continental in particular, don’t go out of their way to serve homebuilders. They certainly are not going to hold a free ‘Continental College’ any time soon.

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What are my other choices?  Rotax?  No!  I’ve been flying planes that cruise at
2400 rpm.  Reduction for prop rotation or not, the high rpm would never let me
feel comfortable.  UL, short TBO and too expensive.  How about Continental?
Some possibilities here.  An O-200 with and Aeroinjector is a possibility with
less power and high cost.  Then there is the Jabiru 3300.  A real possibility.
Better cost than a Continental, but is it as reliable?  I don’t know.

There are a lot of choices, and you sound like you have looked at most of them. Your previous flight and aircraft ownership background is actually serving to inform and fine tune your choices. Builders just getting started with little or no personal reference have a hard time navigating this selection because magazines and other pilots don’t offer much valid input. Reading our site gives a good look at our perspectives and philosophy, which I hold to be more important that exact weight or cost.

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I like the idea of an engine that I have built myself.  I’m sure that I can do
the job.  Earlier in my life I rebuilt a slant-6 Dodge Dart engine that had been
oil starved and experience cam shaft bearings piggybacking.  I follow directions
very well when I have confidence in my sources.

You sound like our kind of guy. Because I teach this stuff instead of just selling a product in a box, I am particularly good at directions. I find it very funny that if you look at any modern product in a store, the guy who wrote the directions inside was obviously the low man on the totem pole. Every other person involved, marketing, packaging, legal, etc, got more of the budget to work with. Businesses try that in experimental aviation all the time, and it never works. Shiny wrapping paper often = Empty box.

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Although I have never been a fan of the Corvair car,  The engine is looking very
attractive to me.  All of the flying video of the Panther (I’ve watched it all
more than once) allows me to know that 120hp is all that I need.  My greatest
uneasiness is with fuel supply.  Everything I read about the Panther engine
tells me that fuel starvation during basic aerobatics is not a serious problem.
I don’t think that I will know for sure until I try.

If you see the plane fly in person, you will be even more impressed than watching it on film. It captures the eye and holds it. The level of flight Dan gets from a standard fuel system is hardly to be believed. A simple change to a Rotec or Ellison and a flop tube would go even further.

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At this point, I think that the Corvair 3000cc with all of Dan’s tricks is my
best choice.  Of course, I haven’t received any of the airframe kits yet so time
is still fluid.  The idea of building an engine in September is very attractive.

FYI: I live in Orange County California and have building space in the EAA
hanger in Chino.  A road trip to Mexico, MO may be very enjoyable if I were to
return home with a working engine for my Panther.

Our Good friend Steve Glover runs NVaero.com at the Chino airport. The next Corvair College we hold in CA, likely in 2015 will be at his place. However, I would suggest Mexico MO because we bring several thousand pounds of parts and tools to Eastern Colleges, where as we are limited in resources on west coast colleges. If you want to drive back with an engine, we need to get started in a few weeks with a plan that does a little prep work every week: Getting Started Reference page

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Thank you for your consideration,

You are welcome.

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Further reading:

Corvair power for Panther and Sonex reference page

3,000 vs 3,100 cc Corvair engines.

Why Not the Panther engine?

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Above, a rear view of the engine. Behind the harmonic balancer is an alternator driven off the crank through a flexible coupler. It is a  project that Dan and I worked on, that he now sells as a rear alternator kit, P/N 2950.  It retains the balancer and cannot put bending loads on the crank. I have never been a fan of belts on the back of the engine, but this system does not use one. The alternator is the same Yanmar unit we traditional use on the front of the engine.

The intake is a custom stainless part made in our fixture so that it mates with our traditional welded on head pipes. On the bottom of the intake is the Precision mechanical fuel injection unit. Dan has designed the Panther to have tremendous airframe strength. The test wing took more than 9Gs at gross weight in a sandbag test conducted after Sun N Fun. Although Dan designed the plane to be easy to fly, it is capable of impressive aerobatics.