Atlantic Society of Radio Controlled Modellers - Mentor - best way to stiffen the motor mount?

speedbird

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Mentor - best way to stiffen the motor mount?
Apr 29^th, 2011 at 4:56pm

I am just finishing a Mentor - had to wait a week to get my hands unglued!
a 25 fits nicely in it, running with a 13x8 wooden prop to begin with...
Heard about the vibration...and some of the various fixes...
Any pictures?

My word, only two screws to hold the motor/prop to the fuse. 4 others (non-attached - acting as adjustable spacers). The motor/prop assy rocks in pitch but it is stiff about the yaw axis

I would be grateful for any ideas & pictures?
Brian

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Brian

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FLC astroflyer

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Re: Mentor - best way to stiffen the motor mount?
Reply #1 - Apr 29^th, 2011 at 5:23pm

no pictures. but jon fibreglassed the whole compartment around the motor.

he then test flew the plane and checked the motor plate alignment and when satisfied fibreglassed or glued that in place as well.

the mentor is noted for vibration in the motor mount especially when over powered. "overpowered" means different things to different people. just ask jon. Grin

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OLDEST AL the walking spellchecker

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Joe Di Profio God Member Offline "Am I Inverted?? OH CRAP!!" Posts: 587 Dartmouth, Nova Scotia	Re: Mentor - best way to stiffen the motor mount? Reply #2 - May 2^nd, 2011 at 9:34am Liquified viagra could work.....Grundy may have some to spare.
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sugarpops Private Offline ASRCM Forum member! Posts: 625 Lower Sackville NS	Re: Mentor - best way to stiffen the motor mount? Reply #3 - May 2^nd, 2011 at 7:00pm Hey Joe......Bill did have some liquified viagra, but he spilled it all over his fingers, he keeps poking himself...... Sugar
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Joe Di Profio God Member Offline "Am I Inverted?? OH CRAP!!" Posts: 587 Dartmouth, Nova Scotia	Re: Mentor - best way to stiffen the motor mount? Reply #4 - May 3^rd, 2011 at 11:10am That gotta hurt..
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Bill G God Member Offline ASRCM Forum member! Posts: 1375 Truro	Re: Mentor - best way to stiffen the motor mount? Reply #5 - May 3^rd, 2011 at 3:29pm Not as embarrassing as a stiff finger lasting over four hours…. This is the last time I’m taking any of Cousin Harold’s advice.
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speedbird Junior Member Offline ASRCM Forum member! Posts: 98 Edmonton	Re: Mentor - best way to stiffen the motor mount? Reply #6 - May 9^th, 2011 at 7:04pm here is one solution
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speedbird Junior Member Offline ASRCM Forum member! Posts: 98 Edmonton	Re: Mentor - best way to stiffen the motor mount? Reply #7 - May 9^th, 2011 at 7:11pm this is better and inexpensive Small Parts CNC interesting web site and company http://www.smallpartscnc.com/funcub%20universal.html you should paste this into a browser to see the image nice CNC part less than 20$ including shipping.... Brian
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Rob

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Re: Mentor - best way to stiffen the motor mount?
Reply #8 - May 9^th, 2011 at 7:54pm

I have had good success "Beefing Up" the Mentor Motor Mount. I used some thick plywood 3/16" I made a slot in the nose and slid it down in front of the two longitudinal plastic stock mounts. As you can see I also used lots of 30 minute epoxy laced with Micro Balloons. This way the motor is installed using the stock steel mounts held on by Blind nuts through the new plywood firewall. Don't be afraid of using lots of reinforcement to this area,as this motor has tons of torque and will twist the nose of the aircraft,causing a Big Vibration and can shake loose of not well supported. Grin

Rob

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Mentor-3.jpg (45 KB | 431 )

Having Fun doing what you want to do,when you want to do it, and having the Health and Good Friends to enjoy it with

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Rob God Member Offline Hang Loose .......... Posts: 996 Dartmouth, N.S.	Re: Mentor - best way to stiffen the motor mount? Reply #9 - May 9^th, 2011 at 7:57pm Another mod I used with Great success is Flaps ! The mentor does not need them, however it makes for a super dive at a lower speed to get it down in a hurry.......
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Rob God Member Offline Hang Loose .......... Posts: 996 Dartmouth, N.S.	Re: Mentor - best way to stiffen the motor mount? Reply #10 - May 9^th, 2011 at 7:59pm I used a super sharp Zona Saw......and some Robart round hinges in a "V" configuration......... The Mentor is a Good Aircraft,to play with on land or water.....it has a wide speed envelope and good flying characteristics. Rob
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FLC astroflyer Private Offline MULLIGAN driver Posts: 6524 Milford, N.S.	Re: Mentor - best way to stiffen the motor mount? Reply #11 - May 9^th, 2011 at 11:41pm Nice paint rob!
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speedbird Junior Member Offline ASRCM Forum member! Posts: 98 Edmonton	Re: Mentor - best way to stiffen the motor mount? Reply #12 - May 10^th, 2011 at 6:34pm I like Robs Firwall mount Using this you do not have to use a collet on a "reversed motor" it solves the rocking with a four point attachment?
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speedbird

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Re: Mentor - best way to stiffen the motor mount?
Reply #13 - May 10^th, 2011 at 6:38pm

Here are some motor facts
using a 13 x 8 prop overheats the 25 size motor with a 40C 4S

using a prop sizing program i get an 11 x 7 as a good match with 50A max. This with a 60A plush ESC and a 5A UBEC.

the Neodym 25 is a nice fit.
with the 13 x 8 prop I was getting 56A and 768W static and enough thrust to say "I had to hang on to the tail for all I worth". But hot at the end of the run.
I will use the temp gauge on the next run

Just about to try an 11 x 7 for the numbers

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Brian

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JON BOY

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Re: Mentor - best way to stiffen the motor mount?
Reply #14 - May 10^th, 2011 at 10:13pm

Brian, like I said before just use some fiberglass cloth and some resin. This takes just two evenings.Top and sides of the engin area one night, and bottom the next night.Test the plane to make sure that everything is ok then glue in the motor mount and you are good to go. Mine has almost 1400 watts, 15x8 prop, 5 cell lipo,around 70 amps full throttle and held together just fine. I think that you are making too much out of a simple problem. All this takes about 1 hour.... I should know, as this is my second mentor. My first lasted just 4 flights. Cry

Dont ask. Wonderful flying airplane though. Looking forward to my new one.

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SandyM God Member Offline Posts: 1853 Dartmouth	Re: Mentor - best way to stiffen the motor mount? Reply #15 - May 11^th, 2011 at 9:41am or a small pair of vise grips will work just fine .....
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speedbird Junior Member Offline ASRCM Forum member! Posts: 98 Edmonton	Re: Mentor - best way to stiffen the motor mount? Reply #16 - Jun 20^th, 2011 at 9:10pm flies nicely with CNC mount and 4S 25 motor wing does need stiffeners a la Jon Boy Until then just gentle flights
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