LyCon

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Given that the cowling mold for O-320 builders will be pulled off Bob's plane does anyone know if his engine is a Conical mount or a Dynafocal variant? I'm starting to look for an engine and I assume that if I go with an O-320 the engine mount type needs to be identical to his configuration.

Will

[csjohnson65]

You're welcome, and definitely talk to ECi and the folks in your airpark community! You're very fortunate to have all that knowledge and skill nearby!

You don't necessarily need anything special to go inverted, so first determine exactly what type of aerobatics you want to do in the Panther. I watched Dan fly inverted quite a bit last Sunday afternoon. Things like loops, rolls and other basic aerobatic maneuvers don't require anything special. The keys are how long you want to stay inverted, and if you might pull enough G's in a manner that stops the oil flow/pressure for too long.

To remain inverted for something like 30 seconds (probably anything over 10), you'll need inverted oil and fuel systems. Otherwise, there's plenty of aerobatics that can be done without them and even in competition. They add weight, cost, and maintenance. I've heard that flop tubes (fuel pickup tube in one or more tanks that are weighted on the ends and "flop" to the top/bottom along with the fuel to ensure continuous flow) require inspection and replacement at least every five years as they can stiffen and stop "flopping." That means removing/replacing wing skins and resealing the tanks, which isn't something I would want to have to do. And, you've got more to inspect and possibly fix during your annuals.

Again, I'm not an expert, but have done a lot of research as I've been thinking about building for quite a few years, and like you I want to occasionally look up to see mother earth. Dan or some of the beta builders can probably provide more and better info. Also talk to some folks at your airpark, ECi, and do some Internet searches. You might even find some YouTube videos of folks doing aerobatics in their RVs and find their builder website or information about their plane on VansAirforce.net. You may be surprised how much you can do without those systems. Panther #1 is the LSA model with a 100hp Corvair engine without inverted oil and fuel systems, and just look what they're able to do in the flight test videos!

[dcrogers11]

Thanks Chris for clarifying the weight issue. I'm in Texas and working near ECI's office in San Antonio, so I might have to venture by and pay them a visit. I was not wanting to get too heavy if I proceed with the build, but wanted to have as much HP as I could as well as inverted capabilities. This is my first build as well and going to have tons of questions. Fortunately, I live in an airpark community surrounded by some of the best builders I know so there may not be a shortage of help.

[csjohnson65]

Yep, ECi specifies "+ accessories" with each of their engines and I fear the flying weight might be closer to 280lbs with "accessories" and fluids. But, it did provide the ability to estimate the weight difference between their OX and IOX models.

[rlweseman]

Hi Chris -
Thank you for the compliments on the Panther. We enjoyed seeing you and Trish, thank you for taking the time to come by.
Regarding the engine choices: Please keep in mind that the weight numbers are subjective and ECI's flyer we have from OSH shows a weight of 240 with no accessories.
Keep up the great research! This is what homebuilding is all about.

[csjohnson65]

At present my preference would be a Panther Sport with an ECi OX-340 (240lbs empty) with a Whirl Wind GA200L (18lbs) ground adjustable prop. I'd love to do an ECi IOX-340 (250lbs empty) with a Whirl Wind 151 constant speed prop (28lbs including governor). Empty weight difference is 20lbs and the 340 is the same size as a 320, but then you have to add in extra fluids and controls for the CS to the weight. Also, the CS option is about $7K more, adds to maintenance, and I wonder if a CS and/or an IO would require a different cowl.

I've spoken to Dan and you can install a heavier engine/prop combination, and aerobatic equipment, you just have to deal with the extra weight on the nose and compensate by putting the battery and possibly other items further back to keep it within CG limits. The Panther was designed for up to an O-320 and a fixed pitch prop to make it light and nimble, but the beauty if the Experimental category is that it's ultimately up to the builder. Heck, John Harmon put an IO-540 in a Vans RV-3 along with some other modifications to create the Harmon Rocket I. As Dan and Rachel note on the Panther website, it's a series of compromises.

The main reasons I'm looking at the ECi 340 is that you can buy it as a kit and assemble it with the supervision of an authorized A&P (I understand Superior has restarted their build school too). These engines are relatively simple, so why not build it myself and know every nut, bolt, and rivet on the finished aircraft? I also like the 2,400 hour TBO and extra HP (up to about 180 on takeoff).

The ULPower UL520i received some consideration as it also has a great power/weight ratio (238lbs and 180hp), and it's a modern design with fuel injection, electronic ignition, and full authority digital engine control (FADEC). But they're a bit more expensive (and USD/EUR exchange rate comes into play), presently limited to fixed pitch props (though the crank is hollow so there is potentially a future upgrade path if ULPower so chooses), max HP is at around 3200rpm vs 2700 for the lyc's, relatively few engines are in operation, and less than half the TBO (at least for now). Very promising though and I still have one eye on it.

The above is based my research. I'm definitely not an expert as I'm a first time builder. Additional thoughts, opinions, and corrections certainly encouraged.

Compromises! Compromises! Compromises! However, I've seen Dan fly the Panther LSA with the 100hp Corvair and Sensenich F/P prop. That thing screams (growls?) across the sky! Panther 1 sure doesn't give the appearance that there was any need for any compromises

[dcrogers11]

No - the IO-320 or a constant speed prop will be too heavy for the Panther.

I can understand that a constant speed prop would be too heavy but I don't think there is much difference in weight between the O-320 and the IO-320 is there?

With a Sky-tec starter, you'll be able to trm a quick 10 lbs. The FP prop is going to come in under 20 lbs I beleive. I hoven't looked at the weight comparisons of a throttle body FI set up, but I beleive they're going to come in pretty close to carbs as well as doing away with the carb heat setup. EI has to save you also over mechanical mags. I just think the IO-320 would be a great engine for the project.

[Rpellicciotti]

No - the IO-320 or a constant speed prop will be too heavy for the Panther.

I can understand that a constant speed prop would be too heavy but I don't think there is much difference in weight between the O-320 and the IO-320 is there?

[dcrogers11]

I'm looking for inverted flight capabilities and had access to an O-320. Is there a chance that an aftermarket injection system and a Christen Oiler system could be used on an O-320 and stay within the weight parameters? I'm looking for as much HP up front as I can hang on it. BTW, I was looking going fixed pitch on the prop.

Thanks,
Don

[mjpalermo]

Thanks for your input Eric. I'm two kits behind you with number 13. Your feedback helps to put me solidly in the undecided category for engines. I was pretty solidly in the o-320 camp yesterday. The IO-233 seems like a great option with weight savings and inverted capability vs. the o-320. The loss in horsepower is of course a consideration (score o320). Less weight on the nose is too (score io233). The availability of mid time or rebuildable 320s is good. I'd need to buy a new IO-233. That's at least $10k more for the 233. The extra 400 hours TBO time is also a big plus as is the electronic ignition.

It's a difficult decision. Fortunately I have an airframe to build while I try to figure it out. I'm looking forward to Bob Woolley's flight report on his sport model with the O-320.