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Date: Mon, 23 May 2011 13:26:55 -0500
From: Charlie England <ceengland@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Center line thrust
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As Ed mentioned, it will add slight nose-down force under power. A lot=20
of high powered homebuilts have down angle built into the mount. If=20
that's true for the Venture, maybe you can take out some or all of the=20
down angle to compensate for the higher thrust line.

As Tracy hinted, are you going to be able to clear the top cowl? It=20
would be a shame to cut up that beautiful aluminum.

Charlie


On 5/23/2011 12:52 PM, Thomas Giddings wrote:
>   Thought you guys might like to see my engine compartment. My plan is =
to mount the Rotary on this mount with a 1/2 " 6061 T6
>   plate. The original design for the Questair Venture used a IO550 Cont=
inental bolted directly(via the oil pan) to this engine mount. Since I ha=
ve no room below this mount because of the nose wheel retracting into it.=
 I am using the mounting plate as a dry sump plate as well. Soooo. the re=
ason I am asking about  raising the Center of thrust is when mounting the=
 Rotary to the original motor mount shown in the Photo and using Marcotte=
 PSRU which rises it another 1.5 in . It actually works out to be around =
3 " after I factor in the height of the mount plate PSRU offset and the n=
atural higher point of thrust with the 20B. I seemed to have missed this =
with all my backyard engineering. The reason i thought this would work be=
tter then LS1 I originally planned to install is how neatly the rotary bo=
lted to the original mount without modification to the motor mount and no=
se wheel retract system. However if you guys think this a none factor . I=
 will proceed . One positive about this I will have a Bigger prop then No=
rmal and it will give about standard ground clearance. Any other thoughts=
 or observations would be welcome.
>
> Tom Giddings
>
> On May 23, 2011, at 12:55 PM, Tracy wrote:
>
>> I'm surprised you are asking about raising it but my guess is that it =
would have negligible effect.  The usual challenge is getting it as high =
as the original thrust line.
>>
>> Tracy
>>
>> Sent from my iPad
>>
>> On May 23, 2011, at 12:41 PM, Thomas Giddings<tom@midwestaviation.net>=
  wrote:
>>
>>> Does anyone know what the effect would be on airframe to raise the ce=
nter of thrust for the crankshaft 1.5 " higher then original design?
>>>
>>> Kind regards
>>>
>>> Tom Giddings
>>> VP Avionics Sales
>>> MIDWEST AVIONICS
>>> 200 Hardy Roberts Dr
>>> PO Box 219
>>> West Paducah,KY 42086
>>> 877-904 9966
>>> Cell; 727 858-1772
>>> FAX:270 744 3466
>>> tom@midwestaviation.net
>>> Online Store
>>> www.midwest-avionics.com
>>>
>>> <  Mi