MOJO 60 Saito 100 vibration
05-02-2009, 08:05 AM
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MOJO 60 Saito 100 vibration
Need some suggestions: I bought a used MOJO 60 in excellent shape with SK 70 installed. Pulled the SK off and installed a Saito 100 for the power with a 14x4W propeller. The 100 installed in the same bolt holes as the SK 70. Started engine up and at above 1/4 throttle i am experiencing lots of vibration, so much it is making the whole plane shake. Tried a different prop brand new same style and balanced. I sent back the motor to the guy that i purchased it from and he ran it on a test stand and had no problems with vibration at all and it ran great. Anyone having vibration problems with thier MOJO and Saito 100??
With the SK 70 i had no vibration problems at all, it would get hot and lose power after about 5 minutes of flying, would land let cool off and it would work ok again for about the same time frame...Checked the high end for it being to lean and did not seem to be to lean even richened it up some and still having the same problem. Head looks like it has some varnish on it dont know it this is from being to hot. Also was running a 14x4W prop on it just like the previous owner did. Just mentioning this to make sure its not a common problem with both...Also tried changing out the fuel tank and the vibration on the 100 was still there...
Any help would be appreciated...Thanks Dane
With the SK 70 i had no vibration problems at all, it would get hot and lose power after about 5 minutes of flying, would land let cool off and it would work ok again for about the same time frame...Checked the high end for it being to lean and did not seem to be to lean even richened it up some and still having the same problem. Head looks like it has some varnish on it dont know it this is from being to hot. Also was running a 14x4W prop on it just like the previous owner did. Just mentioning this to make sure its not a common problem with both...Also tried changing out the fuel tank and the vibration on the 100 was still there...
Any help would be appreciated...Thanks Dane
05-02-2009, 08:41 AM
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RE: MOJO 60 Saito 100 vibration
first put an APC 15*6 on it. The FA 100 is a powerhouse and just like the FA82 it is a vibrating SOB. The motor mount is solid plywood so the vibes have nowhere to go. The new version of the mojo 60 has a different laminated motor mount which should be better. Just balance it and fly it. you should not be flying at full throttle anyway. Also check the profile plane section on this site. also try the Pro Bro website.
05-02-2009, 10:59 AM
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RE: MOJO 60 Saito 100 vibration
What RedFishTom said: put a 15x6 on it. That 14x4 is too small and meant for a 72/82.
Is that motor broken in? Is the prop balanced?
You'll have a dream combo once she smoothes out. If vibration foams up the tank, make sure it's loosely mounted (just a few rubber bands on each side) and consider running the high dollar heli fuel (ie cool power 30%). It won't foam up, and makes the idle nice and slow so you can land it easier with that 6" pitch prop. The Mojo 60 is such a floater.
Is that motor broken in? Is the prop balanced?
You'll have a dream combo once she smoothes out. If vibration foams up the tank, make sure it's loosely mounted (just a few rubber bands on each side) and consider running the high dollar heli fuel (ie cool power 30%). It won't foam up, and makes the idle nice and slow so you can land it easier with that 6" pitch prop. The Mojo 60 is such a floater.
05-02-2009, 11:37 AM
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RE: MOJO 60 Saito 100 vibration
Yes the prop was balanced and had flown it with the SK 70. also the engine that i purchased had at least a few gallons of fuel through it... Has anyone seen major vibration with this setup? and it was fixed with a larger prop?
Also i want it only for 3D so why do you suggest a 15x6 prop i would prefer a lower pitched prop, any suggestions?
Also i want it only for 3D so why do you suggest a 15x6 prop i would prefer a lower pitched prop, any suggestions?
05-02-2009, 11:40 AM
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RE: MOJO 60 Saito 100 vibration
also i tried flying it to see the difference off of the ground and it vibrated so much it would almost make the wings flutter at 80-100 power....mainly the left wing and the motor is mounted on the right side of the plane looking from tail....
05-02-2009, 11:44 AM
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RE: MOJO 60 Saito 100 vibration
For more information also: Once motor was mounted and run the muffler came loose only after about 5 minutes of running that gives you an idea of how much vibration i am having...the muffler was secured very tight also by myself...
05-02-2009, 12:40 PM
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RE: MOJO 60 Saito 100 vibration
I have the same set-up. And it is a common problem,the Saito 100 is a "shaken sob".My covering has split at the corners of the hatches on the wing about 5 times now. I have a zoar 16x4 on the Saito and it rips,give it a try out.The wood lets it spool up fast, and the 16"length will slow the plane down to crawl. On Pro Bro,they is a thread on the shaking and how some guys have modified the engine mounts to remedy this.
05-02-2009, 12:49 PM
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RE: MOJO 60 Saito 100 vibration
ORIGINAL: likestofly
I have the same set-up. And it is a common problem,the Saito 100 is a "shaken sob".My covering has split at the corners of the hatches on the wing about 5 times now. I have a zoar 16x4 on the Saito and it rips,give it a try out.The wood lets it spool up fast, and the 16"length will slow the plane down to crawl. On Pro Bro,they is a thread on the shaking and how some guys have modified the engine mounts to remedy this.
I have the same set-up. And it is a common problem,the Saito 100 is a "shaken sob".My covering has split at the corners of the hatches on the wing about 5 times now. I have a zoar 16x4 on the Saito and it rips,give it a try out.The wood lets it spool up fast, and the 16"length will slow the plane down to crawl. On Pro Bro,they is a thread on the shaking and how some guys have modified the engine mounts to remedy this.
what do you think about the apc 16x4w or 15x4w props ?
05-02-2009, 02:22 PM
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RE: MOJO 60 Saito 100 vibration
ORIGINAL: likestofly
I have the same set-up. And it is a common problem,the Saito 100 is a "shaken sob".My covering has split at the corners of the hatches on the wing about 5 times now. I have a zoar 16x4 on the Saito and it rips,give it a try out.The wood lets it spool up fast, and the 16"length will slow the plane down to crawl. On Pro Bro,they is a thread on the shaking and how some guys have modified the engine mounts to remedy this.
I have the same set-up. And it is a common problem,the Saito 100 is a "shaken sob".My covering has split at the corners of the hatches on the wing about 5 times now. I have a zoar 16x4 on the Saito and it rips,give it a try out.The wood lets it spool up fast, and the 16"length will slow the plane down to crawl. On Pro Bro,they is a thread on the shaking and how some guys have modified the engine mounts to remedy this.
could you please post the link to the Pro Bros forum i tried to locate and could not thanks for your help
05-02-2009, 05:26 PM
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RE: MOJO 60 Saito 100 vibration
ORIGINAL: likestofly
I have the same set-up. And it is a common problem,the Saito 100 is a "shaken sob".My covering has split at the corners of the hatches on the wing about 5 times now. I have a zoar 16x4 on the Saito and it rips,give it a try out.The wood lets it spool up fast, and the 16"length will slow the plane down to crawl. On Pro Bro,they is a thread on the shaking and how some guys have modified the engine mounts to remedy this.
I have the same set-up. And it is a common problem,the Saito 100 is a "shaken sob".My covering has split at the corners of the hatches on the wing about 5 times now. I have a zoar 16x4 on the Saito and it rips,give it a try out.The wood lets it spool up fast, and the 16"length will slow the plane down to crawl. On Pro Bro,they is a thread on the shaking and how some guys have modified the engine mounts to remedy this.
05-02-2009, 07:25 PM
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RE: MOJO 60 Saito 100 vibration
My Mojo 60 does shake a lot and the motor mount is barely enough to hold my Saito 100. I didn't do anything too special when building it except maybe using extra slow cure epoxy to get good penetration into the glue joints in the engine area. I used gorilla glue on the tube and wing joings.
A 14x4 is way too little prop for the 100. If you absolutely want a 4" pitch then use the 16x4. I also prefer a wood prop for faster spool up, but it may be good for you to experiment with a few prop types to check that vibration.
For 3D, I prefer the 15x6 as it gives an excellent blast of air over the tail surfaces when I "gun" it. I have a plain old zinger 15x6 and it's a real treat. The 4" pitch seems too much of an air brake for me on that plane.
A 14x4 is way too little prop for the 100. If you absolutely want a 4" pitch then use the 16x4. I also prefer a wood prop for faster spool up, but it may be good for you to experiment with a few prop types to check that vibration.
For 3D, I prefer the 15x6 as it gives an excellent blast of air over the tail surfaces when I "gun" it. I have a plain old zinger 15x6 and it's a real treat. The 4" pitch seems too much of an air brake for me on that plane.
05-03-2009, 05:58 PM
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RE: MOJO 60 Saito 100 vibration
I'll weight in here, just for grins[8D]...I've built 11 MOJO/Primos and I'm currently flying a MOASS MOJO 60 with my Saito 100. I remember that when the Saito was new it shook but as it ran in it became much smoother. One trick I learned is DON"T use the Saito manual to tune the needles...I think I got this web site here on RCU: http://saito-engines.info/ ...Then go to Throttle set up and tune the engine EXACTLY as they say. The real trick is the low end...not only will the engine run smoother but will use less fuel.
Another thing I did was switched to 30% nitro...Yeah I know it's expensive; but the engine runs soooooooo much better and smoother and is wicked with a 16X4W APC.
One more trick is to go to your favorite home improvement center and buy a length of 3/4" X 3/4" X 1/16" thick aluminum angle. Cut 4 lengths long enough to go from the front of the mount to as far rearward as possible (both sies)...cut one of the lips down to about 1/8- 3/8"...rough up the 3/4" side and the motor mount area and epoxy these rails onto the mount. Then drill for mounting the engine. This forms a sort of "I"-beam support to the mount and stabilizes the whole area back to the wing LE adding very little weight.
That's my story and I'm stickin to it[sm=wink_smile.gif]
Another thing I did was switched to 30% nitro...Yeah I know it's expensive; but the engine runs soooooooo much better and smoother and is wicked with a 16X4W APC.
One more trick is to go to your favorite home improvement center and buy a length of 3/4" X 3/4" X 1/16" thick aluminum angle. Cut 4 lengths long enough to go from the front of the mount to as far rearward as possible (both sies)...cut one of the lips down to about 1/8- 3/8"...rough up the 3/4" side and the motor mount area and epoxy these rails onto the mount. Then drill for mounting the engine. This forms a sort of "I"-beam support to the mount and stabilizes the whole area back to the wing LE adding very little weight.
That's my story and I'm stickin to it[sm=wink_smile.gif]
05-04-2009, 06:43 AM
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RE: MOJO 60 Saito 100 vibration
ORIGINAL: billd3
I'll weight in here, just for grins[8D]...I've built 11 MOJO/Primos and I'm currently flying a MOASS MOJO 60 with my Saito 100. I remember that when the Saito was new it shook but as it ran in it became much smoother. One trick I learned is DON"T use the Saito manual to tune the needles...I think I got this web site here on RCU: http://saito-engines.info/ ...Then go to Throttle set up and tune the engine EXACTLY as they say. The real trick is the low end...not only will the engine run smoother but will use less fuel.
Another thing I did was switched to 30% nitro...Yeah I know it's expensive; but the engine runs soooooooo much better and smoother and is wicked with a 16X4W APC.
One more trick is to go to your favorite home improvement center and buy a length of 3/4" X 3/4" X 1/16" thick aluminum angle. Cut 4 lengths long enough to go from the front of the mount to as far rearward as possible (both sies)...cut one of the lips down to about 1/8- 3/8"...rough up the 3/4" side and the motor mount area and epoxy these rails onto the mount. Then drill for mounting the engine. This forms a sort of "I"-beam support to the mount and stabilizes the whole area back to the wing LE adding very little weight.
That's my story and I'm stickin to it[sm=wink_smile.gif]
I'll weight in here, just for grins[8D]...I've built 11 MOJO/Primos and I'm currently flying a MOASS MOJO 60 with my Saito 100. I remember that when the Saito was new it shook but as it ran in it became much smoother. One trick I learned is DON"T use the Saito manual to tune the needles...I think I got this web site here on RCU: http://saito-engines.info/ ...Then go to Throttle set up and tune the engine EXACTLY as they say. The real trick is the low end...not only will the engine run smoother but will use less fuel.
Another thing I did was switched to 30% nitro...Yeah I know it's expensive; but the engine runs soooooooo much better and smoother and is wicked with a 16X4W APC.
One more trick is to go to your favorite home improvement center and buy a length of 3/4" X 3/4" X 1/16" thick aluminum angle. Cut 4 lengths long enough to go from the front of the mount to as far rearward as possible (both sies)...cut one of the lips down to about 1/8- 3/8"...rough up the 3/4" side and the motor mount area and epoxy these rails onto the mount. Then drill for mounting the engine. This forms a sort of "I"-beam support to the mount and stabilizes the whole area back to the wing LE adding very little weight.
That's my story and I'm stickin to it[sm=wink_smile.gif]
05-04-2009, 08:38 PM
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RE: MOJO 60 Saito 100 vibration
Question for billd3: How did you attach the aluminum L braces? Just with the 4 engine bolts or were there more out on the ends of the braces? Otherwise just the epoxy is holding them on? Thanks.
danemotty: If you don't get enough info here, PM me with your email address and I can send you all of my files on this problem. Do you have Microsoft WORD so I can just attach docs or I can just send emails. GarySS
danemotty: If you don't get enough info here, PM me with your email address and I can send you all of my files on this problem. Do you have Microsoft WORD so I can just attach docs or I can just send emails. GarySS
