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Thread: Floats, Props, Speed

  1. #1

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    Floats, Props, Speed

    Lots of chatter on many threads... what are some average speeds on Edo 2000s in cruise at say 2450?
    What would be considered slow and what would be considered fast.
    How big a difference does pitch make between the 41 and 44 Borer’s? Assuming a 150/160hp.

    I’m seeing 95mph indicated in a 150hp cub on Edo 2000s with 82/41 borer. It indicates about the same whether on 31” bushwheels as well.

  2. #2
    Bill Rusk's Avatar
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    Sounds about right.
    180 Hp, Cato 84/43, Wip2100A, at 2400 I get right about 100mph, about the same on 31" bush wheels.
    Very Blessed.

  3. #3
    G44's Avatar
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    Bill, what are you burning at that speed and power setting?

    Kurt

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    Bill Rusk's Avatar
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    Typically 7.8 down low (<2K) and around 7.2 up higher (6K)
    Pmags really help and I'm running LOP

    Bill
    Very Blessed.
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  5. #5
    skywagon8a's Avatar
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    Quote Originally Posted by CranelakeMN View Post
    Lots of chatter on many threads... what are some average speeds on Edo 2000s in cruise at say 2450?
    What would be considered slow and what would be considered fast.
    How big a difference does pitch make between the 41 and 44 Borer’s? Assuming a 150/160hp.

    I’m seeing 95 mph indicated in a 150hp cub on Edo 2000s with 82/41 borer. It indicates about the same whether on 31” bushwheels as well.
    Many years ago I had the same question, so did some tests with two different airplanes. A stock PA-18-150 on EDO 339-JHS amphibs and a 7GCB 150 hp on EDO 2000s. Started with both planes using the stock Sensenich 74-56 props. Cruise for both was 103 mph which is what I believe was Piper's claimed number. Then using a borrowed McCauley 1A175GM8241 (Borer is the common name for this prop) the cruise speed went down to somewhere in the 95 mph range, the take off time was reduced by 1/3, the climb rate was increased by about 1/3 and there was a noticeable improvement in smoothness. Then, a 1A175GM8244 was tried. Speed went back up to the original 103 mph, the take off time and rate of climb remained the same as the 41 pitch. This was the same on both planes. The -44 was left on the PA-18 and a 1A175GM8046 was put on the 7GCB. It just seemed to me that there was some prop spinning out there doing nothing so the diameter was reduced and the pitch increased to compensate for the reduction. The 7GCB performed the same with both the 8244 and the 8046 props. When both planes were on wheels the cruise speed was still 103 mph. The conclusion was the the speed was controlled by the prop pitch and not the drag from the floats. The 7456 would give a higher speed on wheels. I don't recall the cruise rpm but assume that it was 2400 as that is usually what I use, for no special reason other than it seems about right.
    N1PA
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    PerryB's Avatar
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    That number seems a little optimistic to me, especially for 31's. On 2000's I would consider it plausible but I have a lot of time behind that prop (in a very straight and well rigged 12) and haven't seen anything that good. At 2450 on 31's I'm seeing 91-92, and I've checked the tach and verified the ASI. If you were to check both instruments I think you may find the source of the optimistic numbers.
    After Monday and Tuesday, even the calendar says WTF !
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  7. #7
    RaisedByWolves's Avatar
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    My cub slowed down almost 10 mph when I put the cgr-30p in. Guess my old tach was off. Ran it at 2500 rpm Before and after.


    Sent from my iPhone using Tapatalk

  8. #8
    PerryB's Avatar
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    Quote Originally Posted by RaisedByWolves View Post
    My cub slowed down almost 10 mph when I put the cgr-30p in. Guess my old tach was off. Ran it at 2500 rpm Before and after.


    Sent from my iPhone using Tapatalk
    Well then it seems like a no brainer. Put the old tach back in and enjoy the improved cruise. Right??
    After Monday and Tuesday, even the calendar says WTF !
    Likes RaisedByWolves, Chicken Hawk liked this post

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