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Discussion in 'The light stuff area' started by ryanjames170, Oct 7, 2018.

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  1. Oct 8, 2018 #41

    addicted2climbing

    addicted2climbing

    addicted2climbing

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    Quick question for those in the know.

    How come the Citroen 2CV/Visa airplane conversions can have a PSRU without problems yet a 1/2 VW can not? I have a family member who imports 2CV's and restores them and he has a Visa engine I can have but its in Australia...

    Thoughts?
     
  2. Oct 8, 2018 #42

    blane.c

    blane.c

    blane.c

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    It will be a lot more useful to you when it gets to California.
     
  3. Oct 8, 2018 #43

    blane.c

    blane.c

    blane.c

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    Re: Lighweight opposite 2-stroke engines

    Originally Posted by jbiplane
    BTW we made chemical analysis of plating in cylinder bores of aircraft model engines and were surprised by very low quality. Only german 3W makes it hard and good. Most of good aftermarket chainsaw cylinder and original have really good coating due cost effective serial production.
     
  4. Oct 8, 2018 #44

    blane.c

    blane.c

    blane.c

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    Probably a Lazair, did it have an inverted V tail and engines on the leading edge?
     
  5. Oct 8, 2018 #45

    blane.c

    blane.c

    blane.c

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    One of the downsides to extra engines in conventional aircraft is extra drag. Extra drag from the engines isn't necessarily a bad thing for ultralights because you need to have a little more drag in order to have a little more hp and stay under the speed limit in the 103-7 formula.
     
  6. Oct 8, 2018 #46

    Hot Wings

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    What does it say about something like a 45 mph climb speed?

    My TN 212 based spread sheet agrees pretty well at 61 but isn't so good at climb speeds.

    I can't say I'm "in the know" but I too have wondered about this. IMHO this may be another urban legend because someone somewhere tried to put a PSRU on a 1/2 VW and just screwed it up well. IF the 2CV/Visa reductions are performing acceptably then the same approach should be adaptable to the 1/2 VW. Given that there is evidence that even the uneven firing V-twins can have a reduction added only tends to discount the collective belief that the 1/2 VW can't be reduced.

    I started on such a project when I was still considering a !/2 VW for my Quickie. Even ordered parts based on a Gates belt design, but in the end there just isn't any place suitable to mount the thing to the nose of a VW, other than the generator mounting pad and the universal rear engine mounts (if the case is so equipped). What is really needed is a modern version of the Global/Mosler with a reduction as part of the plan.
     
  7. Oct 8, 2018 #47

    addicted2climbing

    addicted2climbing

    addicted2climbing

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    Well thats true, but what about my question in regards to the PSRU
     
  8. Oct 8, 2018 #48

    addicted2climbing

    addicted2climbing

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    Looks like its 60kg for 35hp but it does have a PSRU. The Pegasus 0-100 is about the same weight and does not need a PSRU and more HP. Just too much weight for any Part 103 aircraft.
     
    Last edited by a moderator: Mar 20, 2019
  9. Oct 8, 2018 #49

    ryanjames170

    ryanjames170

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    so i am going to toss this out here.. could a person mod something like the legal eagle to take twin engines? pushing them out on the wing. if one could keep the weight and balance?

    idea might be for HP use a engine that is rated for 15HP normal but be able to push it threw a gate for a extra few HP during the engine out condition to basicly get a extra long glide? i would need to weigh it but i know the 13HP predator engine is almost 75lbs how ever it has. a starter and charging magnets on it as well as a "starting/Charging Control box"
     
  10. Oct 9, 2018 #50

    poormansairforce

    poormansairforce

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    What BS are you referring to? I simply provided some weight specs for an engine that has been the focus of several threads here that I personally put on a scale with a simple muffler we built and was ready to run. Direct drive allows the removal of the flywheel. And since some are considering direct drive then where is the BS???
     
  11. Oct 9, 2018 #51

    blane.c

    blane.c

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    What is the weight? Everybody has all kinds of numbers they want to bandy about, but HP at propeller RPM and weight are some main things to consider, rarely is weight included. Trying to figure out what may work is difficult guessing weight. And what the weight includes or excludes because guessing the configuration for a given weight is nearly as useless.
     
  12. Oct 9, 2018 #52

    blane.c

    blane.c

    blane.c

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    The CG is set up for the engine(s) to be out front. A setup like the Cri-Cri may work.
    https://www.bing.com/images/search?q=cri+cri&qpvt=cri+cri&FORM=IGRE
     
  13. Oct 9, 2018 #53

    blane.c

    blane.c

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    All manner of engines have been used on the Cri-Cri reciprocating, electric motors, jet engines.
     
  14. Oct 9, 2018 #54

    jedi

    jedi

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    Not familiar with either engine but I see the 2CV/Visa has a belt reduction. Belt drive is much more forgiving of torsional vibration issues. However, the belt tension puts a side load on the crank that the engine may not be designed for. Then post # 46 points out that the VW does not have a way to mount the belt pulley. Add a drive shaft extension and additional bearings and you have a heavy failure prone PSRU that is not needed for the RPM the VW turns.
     
  15. Oct 10, 2018 #55

    spaschke

    spaschke

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    The probability of engine failure may have increased but the probability of an unpowered landing decreased and therefore off airport landing probability has decreased.
     
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