Conference vmszoo::rc

>                      <<< Note 1667.0 by CSLALL::ONEILL >>>
>                        -< closing the barn door..... >-
>
>    This note probably should be under engine mount questions
>    but that note hasn't seen activity since 1991. Hope no one minds
>    me asking here. I'm about to complete a Sig cub. It was given to
>    me all framed up, ready to cover. My problem lies in the the way
>    I should mount the engine. Keeping it scale would mean I need to
>    invert it. If I do, will I need a glow plug lighter to achive a 
>    reliable idle? (O.S. 35). I have no problem side mounting it ( I
>    love scale but im not looking to go all out on this ship) but the
>    instruction state, I'll need to remove some material from the front
>    two formers in order to get the tank high enough and the sheeting
>    is so pretty, I'd hate to rip into it. So guys, in an effort to get
>    back in the air A.S.A.P., can install the engine inverted with 
>    good results or will it be worth the effort to side mount it in 
>    the intrest of less troublesome operation. Do inverted engines
>    produce alot of problems? Thanks for any and all help.
>    
>                                                                Jim

I have a small SIG clipped wing Cub.
I mounted an OS .40 Surpass inverted and it required a battery to keep
it running.

Two things you should know about this that I can think of.

1.  Cubs usually come out so light that the battery weight is not a problem.
2.  Cubs tend to nose over on landing there by scraping up the cylinder heads.

I have so far lucked out and don't appear to have a scratch on my 4 stroke
head but I do frequently fly off tar so I know it is just a matter of time.

Personally if it were me I would put it in sideways.  I would bet it would
run just fine if you just put the tank as high as possible without the butcher
work.  If not - consider a small chicken hopper buffer tank mounted high
and close to the engine.  But I wouldn't do that until after the simple
installation failed.  Some engines can run with the tank off center
quite a ways.  After all that is what holding the nose up and pinching
the fuel line is all about.  Others can't.

Bye          --+--
Kay R. Fisher  |
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    The OS .32 in my Helicopter is mounted inverted. I don't use a glow
    plug heater, and the engine is perfectly reliable. However if the plane
    is fairly light and I had the room, I'd use a glow driver, just to be
    on the safe side.
    
    Wayne.

    Thanks for the help, and I welcome any other comment/advise on
    running an engin inverted. I spoke with a hobby shop owner last
    night and he said he's run alot of engines inverted with little
    if any difficulty. So, in the intrest of geting this bird airborne,
    im gonna install it upside down and see how it goes. If I have to,
    I can always add a battery later.
    
    P.S. Anysuggestions on making a dummy engine for a piper cub?

>                          -< what about the muffler? >-

Hmmmmm, don't know about the muffler - I had a 4 stroke and
could point the muffler at will.  Lotsa guys use Davis Diesel
in cowl Mufflers but they cost a lot.

>    P.S. Anysuggestions on making a dummy engine for a piper cub?

Now your getting to the fun stuff.

The nice thing about the cub is the sides of the cowl never hit the
ground.

You can make some rectangles out of balsa or ply and round the corners
off.  If you make a set of one diameter and another smaller set and
sandwich them together they make very good looking cylinder heads with
cooling fins.  Then make some balsa parts that look like valve covers.
Then use some scrap brass tubing for exhaust pipes.  Then make a air
duct cowl to direct the airflow over the heads out of something thin
that you can bend and harden.  I used paper then fiberglassed it.
Paint most of this stuff flat black and from 10 feet it will look wonderful.

With a couple good pictures and scrap and an evening or two you can
make a super dummy engine.

Bye          --+--
Kay R. Fisher  |
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    Next Question,
    
                     I used a dave brown engine mount on the firewall
    of my sig cub instead of the two aluminium mounts supplied. I noticed
    this mount moves the engine out a little further than intended. I took
    a measurement (rough) from the plans which I assume are drawn full
    size, and find prop washer is out almost a half an inch past where the
    cowl ends ( again, on the plans). Im sure all I have to do is mount
    the cowl out that much further, right? Should I have stuck with the 
    supplied mounts?
    
                                                    Thanks guys

>    Next Question,
>    
>                     I used a dave brown engine mount on the firewall
>    of my sig cub instead of the two aluminium mounts supplied. I noticed
>    this mount moves the engine out a little further than intended. I took
>    a measurement (rough) from the plans which I assume are drawn full
>    size, and find prop washer is out almost a half an inch past where the
>    cowl ends ( again, on the plans). Im sure all I have to do is mount
>    the cowl out that much further, right? Should I have stuck with the 
>    supplied mounts?

Unless your going to compete in scale it probably don't matter.
In static judging you would lose points from the Accuracy of Outline judge.

The only issue with having the engine a bit forward is weight and balance.
In a typical cub this is never a problem.

While we're in the area - do you have some right thrust?
If not put a 1.5 to 2 degree shim in now - you will be glad you did.

Bye          --+--
Kay R. Fisher  |
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################################################################################

    Kay,
              I have'nt got any yet but the plans show a definate
    amount of down thrust. Not sure if they call for right thrust but
    I know from past experience, you usually put it in.
    
                                                              Jim