Engine Mounting?
09-16-2007, 11:36 PM
#1
Thread Starter
Engine Mounting?
I have an evolution .46 where the rear of the motor sits with no play in the mount... However as you move forward, the crankcase narrows, leaving space between the case and the motor mount. This allows the motor to swing left or right off centerline. What is the best way to ensure 0 degree side thrust. I Would like to do something other than the "eyeball it" method however motors I've worked with to date have not had this narrowing of the crankcase and I usually drop them in, slide for or aft for balance and secure.
Mike
Mike
09-17-2007, 05:57 AM
#2
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RE: Engine Mounting?
I always mount the engine in the mounts first, then mount the mount to the firewall...Is this an ARF?
Once you have the proper spacing for the cowl is there play in the engine at the aft of the mount? if not drill those first and secure the aft side first. before you drill the forward holes
make sure that you have enough area on the mount to drill the forward holes without drilling through the side of the mount. if its close re mount the mount on the firewall.
Once you have the proper spacing for the cowl is there play in the engine at the aft of the mount? if not drill those first and secure the aft side first. before you drill the forward holes
make sure that you have enough area on the mount to drill the forward holes without drilling through the side of the mount. if its close re mount the mount on the firewall.
09-17-2007, 07:02 AM
#3
Senior Member
RE: Engine Mounting?
If you have a small or 6" dial slide caliper you can reference all the mounting holes off the back side of the mount, or reference the back two mounting holes in this manner and then use the motor to locate the forward two holes. This will ensure the motor is square on the mount, any side thrust must come from the firewall then if it isn't square to the centerline of the plane.
09-17-2007, 07:52 AM
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RE: Engine Mounting?
What is the best way to ensure 0 degree side thrust.
Ed S
09-17-2007, 08:40 AM
#5
Thread Starter
RE: Engine Mounting?
thanks for the replies...... it's a four star .40 kit.. .. so no cowl... I figured would be easier to secure the mount first.. then the motor since i would have a longer centerline to line up against. There is no side-thrust in the firewall so just need to have it straight on.
I like the caliper idea... looks like cheaper ones are around 10 bucks...
Thanks.
Mike
I like the caliper idea... looks like cheaper ones are around 10 bucks...
Thanks.
Mike
09-17-2007, 12:30 PM
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RE: Engine Mounting?
Block the fuselage so the wings are parallel to the ground. Make sure the engine is centered in the mount with the propellor parallel to the ground. Pick a spot on the centerline of the fuselage and measure to each propellor tip. For zero side thrust the distance should be the same. It is better to err on the side of a little right thrust as left thrust is usually not desirable.
09-17-2007, 02:21 PM
#7
Thread Starter
RE: Engine Mounting?
ORIGINAL: Stew99
Block the fuselage so the wings are parallel to the ground. Make sure the engine is centered in the mount with the propellor parallel to the ground. Pick a spot on the centerline of the fuselage and measure to each propellor tip. For zero side thrust the distance should be the same. It is better to err on the side of a little right thrust as left thrust is usually not desirable.
Block the fuselage so the wings are parallel to the ground. Make sure the engine is centered in the mount with the propellor parallel to the ground. Pick a spot on the centerline of the fuselage and measure to each propellor tip. For zero side thrust the distance should be the same. It is better to err on the side of a little right thrust as left thrust is usually not desirable.
Question... With a propeller spinning clockwise looking from the rear... why would right thrust work as it seems like would just add fuel to the fire?
Mike
09-17-2007, 04:13 PM
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RE: Engine Mounting?
The spinning propellor is putting an opposite torque on the fuselage making it want to roll to the left. It also sets up a spiral slip stream around the fuselage that hits the vertical fin on the left side making the plane want to yaw to the left. These effects vary from one design to another so it's usually best to start with whatever the designer has specified. After you see how the plane flies in a stock set-up you can begin to experiment with other set-ups. As someone else mentioned, after mounting, the engine thrust line can be shifted with shims or washers under the engine mounting lugs or between the engine mount and the firewall.
09-18-2007, 07:47 AM
#9
Thread Starter
RE: Engine Mounting?
ORIGINAL: Stew99
The spinning propellor is putting an opposite torque on the fuselage making it want to roll to the left. It also sets up a spiral slip stream around the fuselage that hits the vertical fin on the left side making the plane want to yaw to the left. These effects vary from one design to another so it's usually best to start with whatever the designer has specified. After you see how the plane flies in a stock set-up you can begin to experiment with other set-ups. As someone else mentioned, after mounting, the engine thrust line can be shifted with shims or washers under the engine mounting lugs or between the engine mount and the firewall.
The spinning propellor is putting an opposite torque on the fuselage making it want to roll to the left. It also sets up a spiral slip stream around the fuselage that hits the vertical fin on the left side making the plane want to yaw to the left. These effects vary from one design to another so it's usually best to start with whatever the designer has specified. After you see how the plane flies in a stock set-up you can begin to experiment with other set-ups. As someone else mentioned, after mounting, the engine thrust line can be shifted with shims or washers under the engine mounting lugs or between the engine mount and the firewall.
Mike
