Engine thrust line

Rotax 912 series discussion.

Re: Engine thrust line

Postby funflyingguy » Sat Aug 31, 2024 10:04 am

appreciate the thoughts and feedback from all. i have other details i can share. thinking i'll post them on a more appropriate topic as this one is for engine thrust line.

jim
3rd owner of sonex #1010 - N485PB
2017 can-am spyder F3T
2013 suzuki vstrom 650
2022 forest river popup camper
concord township, ohio
over 36 years flying
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Re: Engine thrust line

Postby funflyingguy » Sat Aug 31, 2024 5:30 pm

skippydiesel....

"I use a P profile, self adhesive, gap seal. Works very well. Take your time in placing it so that the canopy only just compresses it at the contact point."

do you happen to have a picture of your gap seal? i have what i think is a rather unusual issue with the back edge of my canopy. it is not a continuous curve, but califlower shaped! the edge goes in and out, in and out, repeatedly from edge to edge, with almost a 1/2" gap at the widest points. my guess is that the builder did not cut the side edges short enough causing the canopy to sit high. he then secured the rear canopy edge by drawing down the canopy to the curved aluminum bar at about 4" intervals as much as he dared. probably heated it as he did so to avoid cracking. so i have an uneven gap in places. also, not sure if this is common, but the back edge of the canopy doesnt quite reach the top of the fuselage, leaving about a 1/8" gap there too. so fixing my canopy gap seems more complicated. i have some ideas, including attaching a curved, 1/4" aluminum trim piece along the top edge of the fuselage just short of contacting the canopy then using soft rubber door seal to close off most or all of the remaining gap.

still thinking this one through.......

jim
3rd owner of sonex #1010 - N485PB
2017 can-am spyder F3T
2013 suzuki vstrom 650
2022 forest river popup camper
concord township, ohio
over 36 years flying
funflyingguy
 
Posts: 43
Joined: Fri May 17, 2024 8:22 pm

Re: Engine thrust line

Postby funflyingguy » Sat Sep 28, 2024 3:58 pm

Skippydiesel wrote:other projects with my sonex are calling. here are a few:

. better gap closure and seal at the back of my canopy.

I use a P profile, self adhesive, gap seal. Works very well. Take your time in placing it so that the canopy only just compresses it at the contact point.

. left brake slightly grabbing, pulsing with or without center pull brake applied. (brakes are new and 'broken in').

Sounds like a warped or misaligned disc. If drum brake could be a loose or misaligned shoe.



i replaced the sonex after market finned brake drums with the stamped steel originals just received from sonex. what a difference! clearly proves at least one drum was warped. i had a local machine shop turn the finned drums. when i came in to get them, they told me they had to charge me more because they had to take off more that expected to get them round! LOL. anyway, i'll keep the stamped steel ones on the plane for now, until they have issues. nice to have a backup set. BYW: not thoughts at this time replacing my brake cable actuated system with a hydraulic one. i am now able to hold the plane stationary up to 2500 RPMs, easily enough for short field takeoffs and runups.

i may have mentioned elsewhere, perhaps related to excessive cabin noise i am having. but i bought nearly the same weatherseal as you recommended. i'll be putting than on shortly. really curious if that significantly cuts the cabin noise. thanks all.......
3rd owner of sonex #1010 - N485PB
2017 can-am spyder F3T
2013 suzuki vstrom 650
2022 forest river popup camper
concord township, ohio
over 36 years flying
funflyingguy
 
Posts: 43
Joined: Fri May 17, 2024 8:22 pm

Re: Engine thrust line

Postby SonexN76ET » Sat Nov 02, 2024 7:32 pm

After readjusting my engine mount to have to thrust line 2 degree to the right for a Rotax 912, the plane is flying straight and true. I did notice during the run up the engine twists back to the left. My spinner tip moves over an inch to the left. That is with the early (first ten produced) engine mount with the AN4 bolts and thinner tubes than the newer mounts from Sonex.

Jake
Sonex Tri Gear, Rotax 912 ULS, Sensenich 3 Blade Ground Adjustable Propeller
MGL Velocity EMS, Garmin GTR 200 Comm, GTX 335 ADS B Out Transponder
ILevil AW AHRS & ADS-B In, UAvionix AV20S
200+ hours previously with Aerovee engine
Sarasota, Florida
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Re: Engine thrust line

Postby Skippydiesel » Mon Nov 04, 2024 3:15 am

My Legacy/Rotax 912 ULS requires corrective rudder on Take-Off and high power Climb out. In Crusie she flies straight, ball in the middle.

I have a very small aluminium curved profile, fixed trim tab, trailing edge of the rudder, about 50 mm high and 15mm wide (not including where its stuck on with double sided tape) to correct a slight yaw.

I raised the front of the engine by about 2mm, using large flat washers, to reduce the need for up elevator in cruise.
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