Hey guys! Ive been meaning to jump on here for awhile but havent gotten to it. Im the first guy (at least in public knowledge) to mount a forced induction Apex on a super cub. To clarify, it is NOT in the air yet as my build is not completed, but I do happen to have a wealth of hands on knowledge of the subject.
To answer the original question, yes, horsepower is horsepower, but the real sex appeal of the Apex is that it can use said horsepower in a way that is SUPER conducive to our application, and in my mind at least, far superior to existing options.
Lets make this more of a conversation about static thrust vs static thrust for a second here.
Its not all about HP or torque. Doesnt matter how we get there, its about the thrust we put out that really matters.
Hypothetically if you have an IO-390 at 200hp and say an 84/43. (Im guessing here) but Id imagine youd be putting out around 775-800lbs of static thrust.
With a forced induction Apex at 300hp paired with an 82 3 blade GA composite prop, 1000lbs static has already been made.
Sure, it takes a ton of engine rpm to reach that, but on average, how many seconds would it be necessary to hold that kind of power in a cub? You know the answer, its seconds. And guess what those sled engines were built for AND historically have proven to be GREAT at doing reliably? 15-30 seconds of sustained WOT, then back to normal operating rpms.
How many HP do you figure you actually utilize at cruise? Its not all that much. So to match you performance wise, I can chop my throttle back to a pretty acceptable rpm 98% of the time.
So thats the thrust argument. Now lets move on to weight comparison.
My turbocharged Apex engine complete with gearbox weighs in at roughly 205 lbs.
The IO-390 is i believe something like 310lbs dry, right?
Answer me this. How many of you guys would rather fly a hopped up 320 over a 180 because of the friendlier characteristics? Or better yet, how many guys loved flying the -18 90hp because it flew SO much better? It just didnt have the snort to be effective in our application.
A light cub is a happy cub!
We have always had to walk a fine line between power to get you out or a nice flying airplane. I believe that those days are over, at least for me.
As a young guy, Im pretty apt to embrace newer technology and wonder why we as an industry are still governed by outdated technology. I mean, when is the last time you purchased a car with a magneto or a carb?
You get my drift.
Anyway, to try and keep this somewhat short and answer as many questions as I can in one shot, Ill just throw out a quick list of a handful of reasons that I value the Apex in my build.
#1 the Apex has a long track record of being boosted and getting the absolute **** kicked out of it with great results.
They have been a hot item to builders for years because they can be built to asinine power levels. There are guys who have pushed 800hp out of Apex engines in drag sleds. Not reliable in that highly modified configuration obviously... but still, that gives a bit of context. There have been hundreds of thousands of hard sled miles on 275-400hp apexs with a GREAT track record.
#2 My Apex is light!
205lbs with PSRU. That gives me two Huge gifts. Weight savings and the ability to add a little bit of that weight back in fuel!
#3 fuel injection.
No carb heat!
Yes, more tech, more things to go wrong.... but I have taken a huge amount of time to design everything from my custom standalone ECU to my dual fuel pumps in a double redundant fashion.
I can provide more info on that end if it interests you.
#4 price
My Apex is the whole package. I went with the best of the best everything. 300hp, low comp pistons, forged rods, upgraded piston oil squirters, stand-alone ECU with a million custom parameters and safety protocols (compensates fuel maps for altitude by the way), full mil spec wiring harness, and double redundant EVERYTHING. The PRSU used by us is not your every day rotax gearbox. This thing is a work of art and has been BEAT ON by many for a lot of hours with no failures as of yet. Anyway, heres the best selling point. Im pretty realistically only into this engine (complete with PSRU) for around 15k. That speaks for itself.
The prop options are good and CHEAP as well. I picked up my carbon fiber 82 3 blade ground adjust with hub and spinner for under $1200
I hope that I was able to at least answer some lingering questions and shed some light on the subject!
-Sam