Keep in mind that a bladder doesn't make the engine go faster.  It just feeds fuel to a venturi that was opened up to make the engine go faster, but can't draw fuel anymore.

 Hmm, never heard of the "Pipe Bomb" or "Rubber Ducky", must be some sort of Skunkworks code lingo. 

The yellow one pictured are my favorite and are nearly indestructible.

Plus that yellow makes a very visible prop arc to keep your fingers out of.

Mark

  That's impressive Mark.
If you can get the needling
problem solved, you probably
have the best running Testor's ever.

Sow's ears to silk purses. 

-K.

Pretty cool, Mark. Those blue hemostats look familiar, did you get them from me? I've had good luck with the Cox Bees on a bladder, they open up and scream a really steady tune.

Here's my little Reed Speed Mustang from our Cox Engine Forum contest back in 2014. It had a Bee  crankcase with a KB big-hole backplate and I think a Tee Dee cylinder. I was afraid the bladder pressure would just blow the reed open, but it ran great.
Rusty

I can't get it to play unless I click the youtube logo, maybe it'll work better for y'all.

Most senseless 1/2A? Perhaps, but I am absolutely amazed!  I biggest concern is that you are spinning that POS prop way faster than it was ever intended.  PLEASE BE CAREFUL, better still, please throw that prop away...

Dennis, I agree about the yellow safety tip prop at high rpm, but 14.7k doesn't seem all that scary... to me. It was just another one of Mark's many experiments, that's what he does for fun. So far he still has both eyes, all 10 fingers, and some of his teeth, Lol.

But my little Mustang was spinning an APC 5-3 at about 19k without one single hiccup, There is nothing senseless about that, it's a badass little plane. It was even able to fly loops and inverted laps after the 10 official timed laps were done. And that was with only 15° of elevator deflection.
Rusty

Rusty,

Yup!  That's a pair of hemostats that you gave me in a bladder care package a few years ago.  Thank You Very Much!  They come in handy for refueling and prepping the engine.  I'm not as fast as you when trying to get them un-clamped when the engine starts on prime.  I've tried a couple of different things to clamp off the fuel tubing on start, but I found something I really like by accident with this plane.  Having that cheek block on the inside of the nose makes it really easy for me to pinch the fuel hose with my forefinger when I flip the prop.  I think from now on that I will make 1/4" cheek blocks on the inboard side of my 1/2A planes if I think I'm going to go bladder with them.  I'll have to make time to do more product engines on bladder to get the most out of them.  I waffle between new 1/2A projects, and new projects for larger engines.  I want to get into competing (someday...), so I'm playing with four cycles and such to get used to more appropriate sized stunt ships.  But I still keep starting up new 1/2A projects, because I just can't help myself.


Dennis, keep the comments coming.  I'm always willing to hear someone else's thoughts on safety.  I run the yellow safety tip props on my Cox Bees and product engines, and on my Testors and Wen-Macs because they are relatively low speed engines.  I'd not use it on a TeeDee that was screaming.  As I said above, I love the bright yellow prop arc they give.  I haven't gotten bit by a yellow rubber ducky yet! (Now watch...).  Also, you can't tell from the video, but I always wear eye protection when I'm running my engines.

Dave, I could probably get some more speed out of this engine if I went with a different prop, and maybe a little better needling, but I don't know how much more speed I could get out of an old pipe bomb before it eats itself.  I don't know for sure, but I doubt that they would be happy running more than 16 or 17K.  I figure 15K is a very good neighborhood for these Testors/Wen-Mac/AMF engines.  And on a 1/2A model with the Cox prop shown, history shows me that a light plane will get up and boogie.  I was amazed at what my Baby Ringmaster with the 5x3 rubber ducky was capable of doing when it was flown by a person who knew his stuff.  The plane above weighs 5 1/2 ounces, not the greatest/not the worst, but it should be happy flying on a 5x3 at 14.7K. 

Mark

Mark

Dennis, please don't hold back any good safety advice. Sorry, my reply may have sounded more snarky than I intended. Do you play with any 1/2A planes these days? Seems like lots of guys did back in the day, but not so much now. Revisiting the little ones can be a lot of fun, especially if you only have a smaller area to fly. I'm glad to see some new interest in 1/2A stunt lately. First Brodak, and now the Triple Tree contest at Joe Nall. And we're planning a contest for our 1/2A day in Huntersville this Fall. Sounds like lots of fun... and cussing.
Rusty

There was a guy in our neighborhood who was blinded in one eye by a shed Top Flite nylon prop.  Dad never let us use TF nylon props after that - except on Cox reedys.  We did use Tornado nylon props but never over 10" dia - best prop ever on a McCoy 35 RH.  Dad also taught us about not standing in front of the prop or in the arc (sideways).  Some lessons stay with you I guess.  Another worry is that nylon props do not age well. Over time they tend to dry out and get brittle.  I wonder if that would apply to the prop Mark was using?  What material is it? How old is it? Who made it?  Enough of those questions will turn you into a glider-only flyer!

You asked about my 1/2A's: my little brother & I burned literally GALLONS of fuel through our reedies.  I remember one episode where we used enough of the 40% Rat Race fuel that dad & the big brothers had to go buy some more before they could race that weekend.  We took the 60% fuel one day, my engine couldn't handle it but Alan's went like crazy - swore it was leaving sparks behind it!

Never did "true" 1/2A stunt.  The guys doing it back in the 70's quickly evolved to hi zoot engines, many with bladders and (it seemed) spent more time working on equipment than flying - that never appealed to me.  Funny thing is that I MIGHT have been the spark behind the renewed interest in 1/2A Stunt - I made some comments about it at last year's Brodak Fly In, thinking we could resurrect the small airplanes (many of which fly great) with electric power to remove that layer of stress.  My opinion is that high performance 1/2A engines are necessary for, but also the killer of 1/2A stunt.  Electrics are easy to run in ANY size.  I currently have ELECTRIC powered 1/2A Pathfinder & Wee Duper Zilch (OTS) airplanes that are great flyers and easy to run. I think that simplicity is why the electrics have been expressly omitted from the new push for 1/2A Stunt.  I am disappointed but I will get over it!

BTW I just got a Contest Flyer from the Circle Masters Club up in Milwaukee, they have also added 1/2A Stunt to their annual contest June 2.  The interest is definitely out there.

Mark Mc:  SO SORRY, but it seems I have hijacked your thread!  Keep pushing those engines - just stay out of the "blast" zones!