Homebuilt followup

[mora]

Chairboy is talking about a Wankel Rotary engine:
http://auto.howstuffworks.com/rotary-engine7.htm

[Golfer]

Originally posted by Chairboy

Wow a history, economics and aviation lesson all in one.

I won't compare specs because there really isn't a need.  The little Pitts in the hangar is going to have an O-360 with a good deal of personal touch.  I ever build an RV it's going to have a straight IO-360.  These motors don't "just break" and they're not a catastrophe waiting to happen.  If they caused that many troubles (the 4 cylinder Lycomings...nothing with six or a turbo) why would someone fork over $200,000 for a 172 to fly 120kts behind a ticking timebomb?


When did you get so afriad of simple engines anyway?  Been hanging around a few EAA wingnuts it seems.  If they tell you next that a 172 is a dangerous airplane...they're fibbing.

[mora]

I wonder why people insist on using ancient technology. Maybe they are the ones afraid and not vice versa?

Not that Wankel is anything new, but it's small, light, simple and reliable, and reasonably fuel efficient. Those are exactly the qualities of a good aero engine.

[mars01]

I'll fly my family behind proven technology. If there was something that much better...wouldn't they be using it? It's old...but proven.

Chair, you seem to be caught by emotion and what looks good on paper rather than tried and tested.

While I agree no company is going to spend the time and money to certify new technology, I disagree that Lycs are 1930s technology and that is why they are a bad choice.  Do you know how old the Wenkle technology is.  Lycs have evolved just like everything else.

Again you should look at the numbers of lycs out there performing every day compared to number of failures to get some perspective.  

If you were talking about Continentals I would whole heartedly agree with you, but the Lycs are good motors and proven.

I hope the Rotary does work.  It definately looks great on paper.  I would not put much stock in the "Its works great in a car" logic.  They are two totally different animals and the logic does not work.

I have an email in to the site you linked to to find out if anyone is using the Wenkel for aerobatics.  I am thinking of building an Edge 540 or Pitts S11B and like I said the Wenk looks good on paper and I like the idea of an easy rebuild.  

But then I get to thinking...   After investing all that money and time into the plane, would I really want to roll the dice and take the chance of being the guy that hits the 1 big snag?  Food for thought, not because I swear by Lycs, but because they are proven and you rarely get a second chance once you are wheels up.

[Chairboy]

Originally posted by Golfer
When did you get so afriad of simple engines anyway?  Been hanging around a few EAA wingnuts it seems.  If they tell you next that a 172 is a dangerous airplane...they're fibbing.

The EAA is full of Lycoming/Continental/Franklin/etc fans.  This is from an evaluation that uses basic risk assessment techniques.  I think there's a bit of unwarranted fawning over those aircraft engines that's a bit unusual.  No need to get riled up about it, and I'm not afraid of Virginia Wolf or these certified engines, I just think that there's something better and I'm willing to put my money where my mouth is.  

After all, it's an experimental aircraft, right?  The purpose of experimentation is to prove/disprove theories, and my theory is that Rotary's are better suited for my purpose than a Lycoming.

Time will tell, and I'll be sure to report back with my progress.

[Chairboy]

Originally posted by mars01
Chair, you seem to be caught by emotion and what looks good on paper rather than tried and tested.

With respect, I think that the emotion is on the side of the Lycoming fans.  I'm just trying to make a straight-forward assessment of the technology based on past performance, size of industrial base, status of improvement, and so on.

Originally posted by mars01
But then I get to thinking...   After investing all that money and time into the plane, would I really want to roll the dice and take the chance of being the guy that hits the 1 big snag?  Food for thought, not because I swear by Lycs, but because they are proven and you rarely get a second chance once you are wheel up.

Fair enough, but you face the exact same question with the Lycomings.  They aren't failsafe, they DO break, and thousands and thousands of people have died because of those breakages.  

Tain' nothing mystical about the Lycoming, it's just a straight-forward, well engineered engine.  There's a reason it's been around this long, aside from the economics of engine development which Golfer made fun of, and that's that it's a good, known quantity.  My position is that the Rotary seems like it might be even better (and I KNOW it's smoother), so I'm going to use it instead.

[capt. apathy]

Originally posted by mora
Chairboy is talking about a Wankel Rotary engine:
http://auto.howstuffworks.com/rotary-engine7.htm

thanks, that makes much more sense.  I've never seen how one works before.  

never could get my mind around some variant of this-


in a car.

[Chairboy]

Capt Apathy: But how about a motorcycle?  Cue the Harley Davidson, an aircraft engine missing 8 cylinders.  

[capt. apathy]

lol.

IIRC, in the Camel that whole mess spun around the crank shaft.  right?

I was picturing that in the little plane of yours.  it wasn't pretty.

[JTs]

Originally posted by Roscoroo

You will have to intercool the turbo also.

unless he is going to use a supercharger or put another turbo on its an aftercooler.

[Chairboy]

I plan to intercool the turbo, heat kills components, and I want this to be bulletproof.  Variations of P-51 style scoops are being tried with good results as alternatives to the NACA scoop, but we'll see how it develops.

[JTs]

an intercooler is used when the charge air is going to be compressed again using a supercharger or another turbo. an aftercooler is used when the charge air is compressed only once.  cooling the turbo is well cooling the turbo.  i have a Caterpillar C-16 (just short of 1000 cubic inches) rated at 800hp @ 1800 rpm (1050 hp on nitrous for 15 seconds) and cool the turbo with engine oil which is cooled by an extened range oil cooler using engine coolant at an aveage temp of 185 deg.  but then i'm not an aircraft mechanic and you guys may use different terms.

[capt. apathy]

Originally posted by JTs
an intercooler is used when the charge air is going to be compressed again using a supercharger or another turbo. an aftercooler is used when the charge air is compressed only once.  cooling the turbo is well cooling the turbo.  i have a Caterpillar C-16 (just short of 1000 cubic inches) rated at 800hp @ 1800 rpm (1050 hp on nitrous for 15 seconds) and cool the turbo with engine oil which is cooled by an extened range oil cooler using engine coolant at an aveage temp of 185 deg.  but then i'm not an aircraft mechanic and you guys may use different terms.

I have a 760 turbo Volvo with an inter-cooled turbo.
it's just one turbo, no supercharger either.

the turbocharger is cooled internally with engine coolant, and lubricated with engine oil.

inter-cooled (cooled inside I'd suppose) turbo's last much longer.  I've got over a 1/4 million miles on the original turbo charger.

edit- IIRC the turbo is made by Mitsubishi

[Holden McGroin]

Originally posted by Golfer
As far as  I'll fly my family behind proven technology.  If there was something that much better...wouldn't they be using it?  It's old...but proven.

When flying a cozy, hopefully you won't be behind the engine technology.

[Chairboy]

Heh, great point.  If your family is behind the engine while flying in a Cozy, something has gone terribly wrong indeed.