Third time not lucky! Tail Dancer's third motor mount bust!

[Hogster]

This is the third time I've bust the motor mount on my Tail Dancer! :o :rolleyes: I had the first flight since my last repair (http://rcgroups.com/forums/showthread.php?t=271961), last night, and it wasn't too good. It appears that during that last repair, I must have inadvertently added some UPthrust when mounting the motor back on the plane. When under power, this subtle problem made the nose pull up, stalling the plane. Here is the video of the crash:

Bad thrust line? (http://hogster.rchomepage.com/bad_thrust_line.mov)

Notice how I launched it flat, and yet it is quickly pointing straight up? That wasn't my control input, that was the upthrust from the motor PULLING the nose up. The strange antics it then performs were caused by the pull of the motor continuously stalling the plane ... I was relieved I could get it down with only minor damage. The noise you hear when the plane lands was the motor mount breaking! :rolleyes:

So here was the damage:

http://hogster.rchomepage.com/dancer/third_motor_mount_repair_1.jpg

The firewall/motor mount had been snapped horizontally just under the central hole, and had also been snapped along the two vertical sides. See the bend in the plate on the motor? It's behind there where the firewall/mount snapped.


And here's how I've repaired it!

Step 1 - Stripped back the SolarFilm around the firewall

http://hogster.rchomepage.com/dancer/third_motor_mount_repair_2.jpg


Step 2 - Snapped all the bits of firewall off with fingers ...

http://hogster.rchomepage.com/dancer/third_motor_mount_repair_3.jpg


Step 3 - Sanded front of fuselage smooth

http://hogster.rchomepage.com/dancer/third_motor_mount_repair_4.jpg


Step 4 - CA'd a piece of 3/16" (not 1/8" as before) balsa to the front of the fuselage, with the grain running HORIZONTALLY. Roughly sanded to required shape.

http://hogster.rchomepage.com/dancer/third_motor_mount_repair_5.jpg


Step 5 - Completed sanding, and made a hole in the middle with a round file for back of stator-mount to poke through. Marked and made holes for screws (using a technique described part way down this post (http://rcgroups.com/forums/showpost.php?p=2596868&postcount=4)).

http://hogster.rchomepage.com/dancer/third_motor_mount_repair_6.jpg


Step 6 - Re-covered front end with SolarFilm and poked holes through the film for the stator-mount and screws.

http://hogster.rchomepage.com/dancer/third_motor_mount_repair_7.jpg


Step 7 - Reinstalled the motor mount, and replaced the Velcro (the black stuff) on the balsa shelf.

http://hogster.rchomepage.com/dancer/third_motor_mount_repair_8.jpg


Step 8 - To counter the UPthrust experienced in the last flight, I have put a thin piece of cardboard padding behind the top two screws, essentially making the motor point down more (adding DOWNthrust). It might need more padding but I'll see how this goes.

http://hogster.rchomepage.com/dancer/third_motor_mount_repair_9.jpg


Repair complete!

http://hogster.rchomepage.com/dancer/third_motor_mount_repair10.jpg


Ready for next flight! :cool:

[ashdec87]

You crashed AGAIN!!! :D Didnt i tell you it was time to start flying and not crashing?? :) Just kidding.

Nice repairs though, your getting good at that.

As soon as you notice that the motor is doing anything screwy, turn it off. Best way to save the plane.

Good luck with your next flight :)

ash

[GaryMC1]

From the last thread:


Quote:
Sorry to hear about your plane..........again.

Hehe! I hope this doesn't become too regular an occurence!

Quote:
damage doesnt look too bad.

AGAIN???

What was that about a 'regular occurence?'

:D

Nice repair job.

Gary

[ashdec87]

Nice repair job.

Gary

Like i said he's getting more experience fixing his plane than flying them. :D

Sorry Hogster, it's jsut too much fun to pick on you for this. :)

ash

[Hogster]

Lol! I can honestly say that this plane has a greater tendancy to crash than all my other planes put together! :o I guess it is a little experimental, especially seeing as this was meant to be a motorless glider of twice the size! With a fuz I redesigned myself, I suppose I couldn't have expected it to be perfect first time! :rolleyes:

Sorry Hogster, it's jsut too much fun to pick on you for this. :)
Hehe, I don't mind at all! If the crash isn't punishment enough, I can always rely on you to really rub it in! :p

[ashdec87]

Hehe, I don't mind at all! If the crash isn't punishment enough, I can always rely on you to really rub it in! :p

That's what i'm here for. :D

And are you sure it's the plane that has a tendancy to crash........ :rolleyes:

ash

[Hogster]

Ohh yess ... quite .... urrr .... quite sure of that ..... :o :p

[GaryMC1]

Now, ask him about the other parts he broke while fixing the nose!!!

And I thought *I* was bad! LOL!!!

Gary

[ashdec87]

Now, ask him about the other parts he broke while fixing the nose!!!


Gary


Please explain. Sounds intresting!!

Ash

[Hogster]

See the last posts in this thread:

http://rcgroups.com/forums/showthread.php?t=277906

I shouldn't have told him! :o

[GaryMC1]

However,
In Hogsters defense, I have to say that his experience in repair work was able to help me fix my airplane when I did something really dumb to it, breaking the horizontal stab. I expected I was going to have to do all sorts of really weird stuff to get it fixed, but Hogster knew exactly what I needed to do, and 15 minutes after he told me, I was putting the airplane back together.

So, while I was tweaking him, I also have a great deal of respect and appreciation for him. I mean, in the Tail Dancer alone, he's got a world of experience, I might as well use it! :p

By the way, are we going to get video of the next flight? :D



Gary

[ashdec87]

Video is definetly needed for the next flight!!

Ash

[Hogster]

I think I should rename the Tail Dancer my Crash-test rig! It's the only plane whose flights have been ended by a confrontation with terrafirma in the past couple of months! Still, at least it's giving me experience in repairing damage to balsa. :rolleyes:

I almost always film each flight, so I'm sure you'll be seeing another crash ... URR I mean flight video soon. :p