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Design => Stunt design => Topic started by: bob whitney on April 25, 2015, 02:50:16 PM

Title: uprite / inverted engine
Post by: bob whitney on April 25, 2015, 02:50:16 PM

 OK i have watched stunt ships go from all uprite engines to mostly Inverted engines, what is the advantage for either one, ???

 i just flew an old school uprite ship built by Dave Platt,( mister Scale ) it did some of the prettiest SQr's i have done in a long time and grooved like it was on rails . why would i want to do this ship as an inverted engine ????
Title: Re: uprite / inverted engine
Post by: Tim Wescott on April 25, 2015, 03:29:03 PM
Probably because a honkin' big cylinder head sticking out the top of the cowl is going to result in fewer appearance points.
Title: Re: uprite / inverted engine
Post by: Lauri Malila on April 25, 2015, 04:06:11 PM

Bob,

Cylinder up or down does not affect much to how the engine runs, actually you can expect more running symmetry problems with a side-mounted engine. But differend engines behave in differend way, it's not possible to give an universal answer.
When cylinder points up there is of course cosmetic issues but you may also face problems with vertical c.g, tank position and possibly landing gear height.
For other than cosmetic reasons I have ended up with cylinder pointing 40 degrees down.

Lauri
Title: Re: uprite / inverted engine
Post by: EddyR on April 25, 2015, 07:29:44 PM
Upright motor requires longer landing gear.
Title: Re: uprite / inverted engine
Post by: Chris Wilson on April 27, 2015, 05:47:38 AM
An invert mounted engine lends itself to a raised thrustline and that promotes slight down thrust, and it seems to clear a flooded crankcase more easily.
Title: Re: uprite / inverted engine
Post by: Brett Buck on April 27, 2015, 09:56:43 AM
OK i have watched stunt ships go from all uprite engines to mostly Inverted engines, what is the advantage for either one, ???

 i just flew an old school uprite ship built by Dave Platt,( mister Scale ) it did some of the prettiest SQr's i have done in a long time and grooved like it was on rails . why would i want to do this ship as an inverted engine ????

   The performance of the airplane is not particularly affected by the engine orientation, assuming it runs correctly. That particular airplane probably does good square maneuvers because it's in correct trim, not because the engine is upright.

     Most are inverted for appearance, and ease of starting.

     Brett
Title: Re: uprite / inverted engine
Post by: Air Ministry . on April 27, 2015, 09:48:57 PM
undercarrage length is shorter general with a inverted injun .
Title: Re: uprite / inverted engine
Post by: Lauri Malila on April 27, 2015, 10:32:03 PM
Oh, and not to forget that landing gear must be taller when cylinder is pointing up. L
Title: Re: uprite / inverted engine
Post by: Chris Wilson on April 28, 2015, 01:14:02 AM
why would i want to do this ship as an inverted engine ????
Why would you use an engine upright?

Some engine look cool upright, especially those with an anodized or painted head or maybe an inline twin to show it off a bit better(?)
Title: Re: uprite / inverted engine
Post by: FLOYD CARTER on April 30, 2015, 12:20:20 PM
 

     Most are inverted for appearance, and ease of starting.

     Brett
[/quote]

I wish that were true.  I really hate having to turn the plane upside down (engine installed inverted) to get it to fire off.
Title: Re: uprite / inverted engine
Post by: Target on April 30, 2015, 12:47:51 PM
I think it's solely to get the thrust line up in the fuse, without the cylinder in the direct air stream.
Regards,
Chris.
Title: Re: uprite / inverted engine
Post by: Brett Buck on April 30, 2015, 05:07:04 PM

I wish that were true.  I really hate having to turn the plane upside down (engine installed inverted) to get it to fire off.

  I find it far easier to start them inverted than upright. Sometimes you can't with piped engines because the oil runs down the pipe back into the engine but otherwise, starting inverted is generally easier.

      Brett
Title: Re: uprite / inverted engine
Post by: proparc on May 02, 2015, 12:55:38 PM
Inverted motor=sexy looks. Upright motor=easier on old guys knees.
Title: Re: uprite / inverted engine
Post by: Avaiojet on May 03, 2015, 09:55:12 AM
I cannot imagine an upright engine with this particular design. Wasn't even considered.