Page 3 of 3 FirstFirst 123
Results 81 to 102 of 102

Thread: New PPONK

  1. #81

    Join Date
    Oct 2012
    Posts
    5,099
    Post Thanks / Like
    Where's the science?

  2. #82
    Steve Pierce's Avatar
    Join Date
    Mar 2002
    Location
    Graham, TX
    Posts
    19,227
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    Where's the science?
    So are you saying that flow matching cylinders doesn't make an engine smoother? Flowing and balancing and paying attention to lots of little things doesn't make any difference?

    I can post all kinds of articles explaining all kinds of this stuff but my opinion has come from flying lots of airplanes and these engines consistantly standing out.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  3. #83

    Join Date
    Aug 2015
    Location
    ME, ID, AK - what time of year is it?
    Posts
    469
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    Where's the science?
    Don’t forget - what goes in must come out. Exhaust “science” must be applied to finish the equation...
    Likes BC12D-4-85 liked this post

  4. #84

    Join Date
    Dec 2006
    Location
    Meanwhile,...
    Posts
    5,136
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    Where's the science?
    Really Stewart. A Laminar flow stream moves more quantity and turbulent flow stream, learned that basic of flow dynamics long before I took it in class. In a pipe, channel or induction manifold the sides, bends, fittings and yes the cylinder valves and the shape of their seats induce turbulence and reducing that turbulence by smoothing and easing the angles makes them run smoother by reducing turbulence and thus improving flow. So to your point more flow = more potential hp and the potential gains are there but yes they are not as dramatic as hanging a turbo.
    Remember, These are the Good old Days!
    Thanks Gordon Misch thanked for this post

  5. #85

    Join Date
    Oct 2012
    Posts
    5,099
    Post Thanks / Like
    Re-read post 45.
    Thanks TCE thanked for this post
    Likes TCE liked this post

  6. #86
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    9,748
    Post Thanks / Like
    PPonk
    For those of you interested in the Pponk conversion. Today I received the current issue of Aviation Digest in which there is a brief blurb on the new STC holder and Aerotec engines which overhauls and provides the XP470 engines which comply with the STC.
    http://northpointaviation.net/northpoint-xp470/
    http://aerotecengines.ca/
    N1PA

  7. #87
    Gordon Misch's Avatar
    Join Date
    Dec 2003
    Location
    Toledo, Wa (KTDO)
    Posts
    3,506
    Post Thanks / Like
    Stewart, it's just 7th grade science - probly before that, but that's the lowest grade level I taught - science is about trying stuff to see what happens. That's where.

    You were asking about empirical evidence, not science - i.e. engineering which is my background - but you didn't recognize that you were doing so, or recognize the evidence, so didn't understand the answers.
    Last edited by Gordon Misch; 01-09-2020 at 11:59 PM.
    Gordon

    N4328M KTDO
    My SPOT: tinyurl.com/N4328M (case sensitive)
    Likes 5CT7 liked this post

  8. #88

    Join Date
    Oct 2012
    Posts
    5,099
    Post Thanks / Like
    We make improvements to affect a result. Theorize-experiment to validate. With respect to engines I've had an interest all my life and a very specific interest in high performance airplane engines for the past 3-4 years. I've talked to the big engine builders (dealt with a few) and have talked to some of the premier aerobatics guys about how to wring out power. In my own engines I've got limits on manifold pressure (normally aspirated), RPM, and known displacement and compression. The big factories know precisely what their engines will develop before they put them on the dyno. The dyno is mostly to prove the engine is producing rated power. In my Superior engine we added a new fuel servo that was said to increase power, and sure enough it made 5 HP on the dyno, which Superior was very impressed with. All cool stuff. With respect to well known engine shops that consistently report approx 10% more power than the factories I've asked the factories what the variable is. They're very hesitant to say anything but my own take on it (and the take of several in-the-know friends) is that the variable is the dyno. That may be in the dyno itself or in the setup, because there are ways to cheat to get higher numbers, but those cheats aren't applicable to a normal installation. Obviously my curiosity and questions have struck a nerve with some guys. I'll leave it alone. I have a really cool high performance engine to install and when it warms up... to fly. I did my research, I asked the questions, I spent my money. The end. Adios, gents. Happy flying.
    Likes CamTom12, FdxLou liked this post

  9. #89
    flyrite's Avatar
    Join Date
    Mar 2013
    Location
    Lyons,GA
    Posts
    478
    Post Thanks / Like
    Some here remind me of my drink’n days and walking into a hole in the wall bar where ya ain’t known... piss’n contests to suit every ol farts desire!
    Love the video Steve,Over on another thread, Should post more of’m, proves that flying still takes place occasionally
    Last edited by flyrite; 01-10-2020 at 04:50 PM.

  10. #90

    Join Date
    Mar 2018
    Posts
    116
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    They're very hesitant to say anything but my own take on it (and the take of several in-the-know friends) is that the variable is the dyno. That may be in the dyno itself or in the setup, because there are ways to cheat to get higher numbers, but those cheats aren't applicable to a normal installation.
    True. And to get an apples to apples comparison, bike guys ask for a certain set of dyno parameters (SAE correction factor, standard CF, smoothing, tire pressure, etc., etc.)

  11. #91
    Rob's Avatar
    Join Date
    Nov 2002
    Location
    AZ06
    Posts
    746
    Post Thanks / Like
    Man has this one drifted.... lol

    Quote Originally Posted by pokey View Post
    All,

    If there are recent experiences with Ly-Con I would appreciate you sharing. It seems everyone likes the PPONK and I am committed to that direction over other options but would like to feel confident of the vendor I am doing business with.

    Thanks in advance for any thoughts on this.
    When shopping for a Pponk, Lycon as in Lycon in Visalia, not Lycon of AZ, was my first choice as well, as it was for my last cub engine. I had flown behind Ken's O-320's, O-360's and a couple Pponk's as well, and really, really appreciated those engines. In the end, knowing that the time frame they tend to quote was 'optimistic' at best, coupled with the fact that Steve Knopp had one in his shop that was half way through the build process, and available, I went that way and couldn't be happier. My Cub engine went to another shop

    Fast forward several years, and my neighbor was looking for some assistance in building up a Pponk for his '56 180. Steve was not as available this time, and we happened upon an IO520 core. Having a serviceable O-470 in the airplane the 520 was sent to Lycon, and I expect it will produce all the expected smiles as well. It has been going in this week, along with the typical 'freshening up' of the usual stuff like exhaust, mount, baffles etc...
    The engine was a month and a half or so later than expected, but to be fair, we never called and checked on it until then, as we had a time gap between when we anticipated the engine, and when we could install it. I'm also pretty sure they knew we had a flyable condition until they were done.

    While I don't regret having Steve K build my engine instead of Lycon (I think he does an amazing job as well). I can't say the same for my last cub engine. It came from a reputable engine builder in CO, and it is no where near as smooth or robust as the Lycon cub engines I have flown. In fact it, a wide deck 160 is a dog compared to the clapped out narrow deck 150 it replaced. I wish I had parked that one a little longer and exercised the patience in having that one built up.

    BTW, some of the posts above tend to suggest that building to 'trade standards' should yield as good a result as any . In my prior life as a building contractor, I used to make a point of reminding both employees, and customers, that 'trade standards' were a pretty low benchmark to shoot for.

    In the end, some shops shine at customer service, some at paperwork, some at speed, and some at build quality. It's pretty rare to get one to shine at two of these points, and rarer yet to get one to shine at all of them. Ask yourself which one of these is most important, and then when / if you start getting impatient during the build remind yourself of that.

    Take care, Rob

  12. #92

    Join Date
    Feb 2006
    Location
    northern colorado
    Posts
    21
    Post Thanks / Like
    All,
    Thanks for the interesting responses and thoughts. Ly-con ( Calif) won me over and l am looking forward to a April delivery date. Installed stock 470 running great so time pressure is minimum.

    Regards,
    Bill
    trust but verify

  13. #93

    Join Date
    Aug 2015
    Location
    ME, ID, AK - what time of year is it?
    Posts
    469
    Post Thanks / Like
    Quote Originally Posted by pokey View Post
    All,
    Thanks for the interesting responses and thoughts. Ly-con ( Calif) won me over and l am looking forward to a April delivery date. Installed stock 470 running great so time pressure is minimum.

    Regards,
    Bill
    Are you planning to change out or overhaul your engine mount?

  14. #94

    Join Date
    Feb 2006
    Location
    northern colorado
    Posts
    21
    Post Thanks / Like
    At this point..... 3 months out I am ...... not sure. Leaning towards overhaul though not yet committed in thought.
    trust but verify
    Thanks Poor Joe thanked for this post

  15. #95
    okmike's Avatar
    Join Date
    Mar 2006
    Location
    Pryor, OK
    Posts
    810
    Post Thanks / Like
    Quote Originally Posted by BTV View Post
    I would recommend Lawson Aviation. I bought my IO 520 converted to Pponk from Knopp. Steve helped with the approval of the hi compression pistons but couldnít help with approval of my C66 88Ē prop. Lawson got my prop approval even though I didnít get my engine from them. I have two friends who used Lawson and have been happy with their engines.
    How does the Pponk do with the C66 88", RPM, shorten your take off distance, what did you have before

  16. #96

    Join Date
    May 2012
    Posts
    48
    Post Thanks / Like
    Quote Originally Posted by okmike View Post
    How does the Pponk do with the C66 88", RPM, shorten your take off distance, what did you have before
    The C66 88Ē is a great prop for me. I had it on my 470 before the Pponk. Itíll turn 2750 on takeoff but pulls harder at 2550-2600. Three blade is at least 15# more on the nose unless itís a MT. The two blade may not get off quite as short as a three blade but is cruises about 5-7 knots faster. Itís all about balance for me. I operate my plane as a two person camping/traveling machine and rarely at gross. Three blade is great if youíre hauling loads and operating at gross all the time.
    Thanks okmike thanked for this post

  17. #97
    hotrod180's Avatar
    Join Date
    May 2008
    Location
    Port Townsend, WA
    Posts
    2,934
    Post Thanks / Like
    Quote Originally Posted by BTV View Post
    The C66 88” is a great prop for me. I had it on my 470 before the Pponk. It’ll turn 2750 on takeoff but pulls harder at 2550-2600. .....
    So do you generally keep it dialed back at takeoff?
    Your engine's making less hp at the lower rpm,
    I wonder if a shorter prop that you could run at full rpm without busting mach
    (and losing efficiency) might be better?
    Cessna Skywagon-- accept no substitute!

  18. #98

    Join Date
    Oct 2012
    Posts
    5,099
    Post Thanks / Like
    My early morning thoughts. Thrust is a product of the prop. If the prop is incapable of utilizing the engine's full power there's reason to change to a prop that can.
    Likes CamTom12, OLDCROWE liked this post

  19. #99

    Join Date
    May 2012
    Posts
    48
    Post Thanks / Like
    Depends on a lot of factors. Taking off above 9k feet in Colorado in the summer the extra rpm is good as itís harder to bust Mach. Down lower usually just dial prop back a couple of turns. If I donít I can feel prop pull harder once I takeoff and dial prop back a couple of turns. Itís mostly seat of the pants feel so maybe Iím wrong. Just doing what works for me. I know Iím leaving a little hp on the table with the two blade but itís not like Iím not landing spots guys with three blade prop are. I donít want the extra 15+ pounds on the nose of a Mac or Hartzell three blade and Iím not convinced a MT is 15,000$ better. I fly a good amount of cross country trips a year not going to the backcountry. Sure is nice to put the 8.50ís on and run 165mph at reasonable power setting with the two blade.

  20. #100
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    9,748
    Post Thanks / Like
    All else being equal, taking that 15 pounds off the nose moves the CG aft, causing the trim to be adjusted more nose down due to reduced down load on the tail. Which by reducing drag increases cruise speed.
    N1PA
    Likes BTV liked this post

  21. #101

    Join Date
    Oct 2012
    Posts
    5,099
    Post Thanks / Like
    My experience with my own PPonk includes very low density altitudes. In front of my cabin winter ops require getting the tail up quickly to skid around a bend and then to lift off and gain altitude quickly to clear trees. Even with winter temps at very near sea level full power works better than dialing the prop back. It's noisy as heck but it provides the best performance. I'd dial it back a little in really cold temps but that was for fear of blowing the engine. I'm not interested in flying in those temps anymore.

  22. #102

    Join Date
    May 2012
    Posts
    48
    Post Thanks / Like
    Quote Originally Posted by skywagon8a View Post
    All else being equal, taking that 15 pounds off the nose moves the CG aft, causing the trim to be adjusted more nose down due to reduced down load on the tail. Which by reducing drag increases cruise speed.
    Also lets you land a little slower since the tail isnít working as hard to balance that extra 15 pounds on the nose
    Likes skywagon8a liked this post

Similar Threads

  1. PPonk ID
    By Eddie Foy in forum Cessna: C180/C182/C185
    Replies: 50
    Last Post: 08-18-2018, 12:48 PM
  2. Knisely or Acorn for PPonk 470-50?
    By JohnnyR in forum Cessna: C180/C182/C185
    Replies: 7
    Last Post: 08-17-2018, 01:19 PM
  3. Acorn exhaust on PPonk
    By JohnnyR in forum Cessna: C180/C182/C185
    Replies: 9
    Last Post: 06-12-2018, 08:55 AM
  4. Hand propping a PPonk 470-50
    By JohnnyR in forum Cafe Supercub
    Replies: 45
    Last Post: 01-14-2018, 04:53 AM
  5. PPonk-50 conversion
    By Tom3holer in forum Everything Else (formerly:My Other Plane Is A....)
    Replies: 3
    Last Post: 10-29-2015, 08:50 AM

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •