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ASK 2100 Repair

jross

Well-known member
#1
Buddy gave me this after slamming it into the ground. He assured me it would never fly right again. Looks like a pretty easy fix to me. Everything else on the plane is mint, including motor and prop. Would love to get it flying, surprise my buddy and thank him again for the free plane!

Glueing the crack on the right side should be easy, it's figuring out what to do with the compressed side that has me scratching my head. I thought about applying heat to see if I could get it part way home. Also thought about cutting slits in the foam to create a mild accordion effect, move the fuselage into alignment and then fill the resulting V shaped cracks with glue. Maybe spray foam. Hack off the excess later. Alignment doesn't appear to have shifted much up and down.

I figure any thrust angle is applied with the large nose mount for the motor, if there is any. I can use that bottom seam to align the fuselage and should be able to get it bang on.

Any advice? Been putting it off because I can't make up my mind how to do it.

Top View
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Right Side View

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Bottom View

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jross

Well-known member
#3
I've done a test fit and even with the crack closed as tight as possible, there's still a large bend. But that's definitely where I'll start.
 

PsyBorg

Wake up! Time to fly!
Mentor
#4
Crumpled foam can sometimes relax back into shape when soaked in warm water.

I remember seeing it done in videos long ago. Maybe search you tube and see what pops up.
 

Tench745

Active member
#5
Crumpled foam can sometimes relax back into shape when soaked in warm water.

I remember seeing it done in videos long ago. Maybe search you tube and see what pops up.
I second this suggestion.
You can pour boiling water over it, dip it, boil it, etc, but the water won't get hot enough to melt the foam and it lets the foam relax back into (almost) it's original shape.
 

jross

Well-known member
#6
You can pour boiling water over it, dip it, boil it, etc,
So my thinking on that. The motor is still attached and I don't want to remove it to soak the foam. I know brushless motors can withstand water. My concern is that the motor is sealed into the nosepiece making it hard to drain water and ensure the motor is dried out. I suppose one could hook up a battery immediately after dunking and run the motor for an extended period of time to help dissipate water.

Next logical step in my old brain says if all it needs is heat, what about a hair dryer? Would that not have a similar effect?
 
Last edited:

PsyBorg

Wake up! Time to fly!
Mentor
#7
No. Heat gun / hair dryer is a focused heat and could produce enough heat to damage the foam.where the water would encompass it and distribute even heat in a slower manor.

You want to relax the foam not bake it.

You could if needed poke a drain hole where the motor is mounted to get most of the water out of that cavity.

The problem comes later if you dont or cant lubricate the motor bearings after getting soaked.
 

jross

Well-known member
#9
You could just pour hot water over it rather than dunking/soaking. Your motor would stay mostly dry that way.
We had a similar thought. I was just thinking about a way to waterproof the motor pod but thought it would take a lot of caulking and plastic to do it. Then dunk it in hot water. I think a hybrid of my idea and your idea will work better and be easier. Make an effort to waterproof the motor pod, turn the plane upside down and pour hot water. That way it can't settle in the bottom of fuselage and leak into the motor pod. Thanks!

Another thought I had was stealing my wife's microwaveable back warmer. It's big. Wrap it around the fuselage. Wrap that in a towel. Poach for 10 minutes, add additional pressure to align if required. Figure some way to hold that pressure while the foam cools. Can probably use some screws and scraps of wood to make a jig.

Regardless of how I heat it, a jig would help hold it in place and allow the foam to "learn" the new/old shape.
 

Tench745

Active member
#10
The beauty of the hot-water method is that the foam already "remembers" the shape it used to be. No jigging needed.
Water gives you an even heat that can't get too hot (210°F). A back-warmer might work, but may be too cold or too hot and may be uneven.
If your motor gets a little wet, it's not a problem. As long as you're not actively washing the lubrication out the motor I doubt you will have any issues.
Personal opinion: you're overthinking, just do the thing. It's your plane and your time, so in the end it's your call. Best of luck with which-ever method you choose.
 

jross

Well-known member
#11
Personal opinion: you're overthinking, just do the thing.
Heh. True enough. I just know from approaching things with absence of forethought has caused me issues in all areas of my life! But I guess there's forethought and thinking it to death. A new Spear build has jumped in front of this repair for now. Planted my lovely new spear into the ground lawn dart style. Destroyed. Wings are still perfect but fuselage is fully crumpled and one wing tore off. Needed some uptrim and I took my eye off it for a second and lost orientation in a hay field. Took me almost an hour to find it in the deep grass. Was unprepared for the speed of the Spear. Even at half throttle it was screaming. Caught me off guard.
 

TexMechsRobot

Posted a thousand or more times
#12
Planted my lovely new spear into the ground lawn dart style. Destroyed. Wings are still perfect but fuselage is fully crumpled and one wing tore off.
Give it to your buddy and tell him it'll never fly again. He'll take it on as a challenge to surprise his friend. I've seen this strategy work in the past...
 

Tench745

Active member
#14
Needed some uptrim and I took my eye off it for a second and lost orientation in a hay field. Took me almost an hour to find it in the deep grass. Was unprepared for the speed of the Spear. Even at half throttle it was screaming. Caught me off guard.
Been there, done that too. Those wings will surprise you for sure.