You have to PAY ATTENTION!
07-09-2014, 08:16 AM
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You have to PAY ATTENTION!
The pride of my fleet is a 50cc Midwest Extra 300, Saturday I had been putting it through it’s paces and after four flights it was time to go home.
As I was taking the Wing Tube out a piece of Balsa Wood ‘POPPED’ out of the Right Wing and landed on the ground! (and it was a REAL good thing that I was paying attention and SAW it!)
The piece was some 3” x 1” and 1/8” thick…!!?? Where did it come from?!!
I spent the next 10 minutes peering into the wing through all of the openings – to no avail…
I repeated the exercise at home with the same result. Not good.
Not wanting to loose this beautiful plane for some stupid reason I decided to do some serious looking early Sunday morning. I picked the most likely spot and cut into the covering, I found a few little things that needed mending in the belly pan but no spot that was missing a large piece of wood… (but I fixed the belly pan concerns while I was there)
So I kept cutting off the monokote… and I opened up half of the bottom of the wing. I could not find anything amiss. But what am I looking at/for…?
So I cut the monokote off of the bottom of the left wing… and I could not find anything amiss. But what am I looking at…?
Now I start doing some comparisons between the two wings and I notice on the Right wing that there is a ‘Rough’ piece of wood near the wing tube…? On the Left wing there is a solid piece of wood! (this is an AHA! Moment)
My lost/found piece of wood is a piece of shear bracing. I noticed that the Wing Tube does not butt up against a ‘Stopper’, the WT is actually some 2” too short to meet the nearest rib. So it would seem that during the flights the WT moves and has ‘finally' cut the shear webbing off! I guess the chap that built the plane did not think that the WT would move…
OK; that’s the problem, now what to do about it!?
I decided to correct the original problem and I built ‘Stoppers’ for the Wing Tube in the wing. Simply – I fit two half sized piece of Shear Bracing in (one on either side of the spars), added some triangular stock to have lots of surface area and then glued on a piece of light ply for the face plate of the ‘Stopper’.
I did this in both wings and made sure that there was enough room for the Wing Tube and less than 1/8” of play. (lots of measuring and sanding)
So now the underside of both wings are wide open and looks like H3ll, I’ve gone this far why stop now? I never did like that 1” Checker board pattern – so I cut off all of the covering and recovered the entire bottom of the wings with basic beige and a couple of Black ‘Invasion Stripes’. Simple, but effective.
About this time my Mrs. walked up and asked me why I was here on a Sunday morning and not flying? My explanation did not impress her any more than the time to complete this repair, I started around 6AM and I finished around 2PM.
Hey, the job NEEDED to be done and I was in the zone!
Only minor touch ups to do now and I will be ready to fly with confidence – next weekend! 
As I was taking the Wing Tube out a piece of Balsa Wood ‘POPPED’ out of the Right Wing and landed on the ground! (and it was a REAL good thing that I was paying attention and SAW it!)
The piece was some 3” x 1” and 1/8” thick…!!?? Where did it come from?!!
I spent the next 10 minutes peering into the wing through all of the openings – to no avail…
I repeated the exercise at home with the same result. Not good.
Not wanting to loose this beautiful plane for some stupid reason I decided to do some serious looking early Sunday morning. I picked the most likely spot and cut into the covering, I found a few little things that needed mending in the belly pan but no spot that was missing a large piece of wood… (but I fixed the belly pan concerns while I was there)
So I kept cutting off the monokote… and I opened up half of the bottom of the wing. I could not find anything amiss. But what am I looking at/for…?
So I cut the monokote off of the bottom of the left wing… and I could not find anything amiss. But what am I looking at…?
Now I start doing some comparisons between the two wings and I notice on the Right wing that there is a ‘Rough’ piece of wood near the wing tube…? On the Left wing there is a solid piece of wood! (this is an AHA! Moment)
My lost/found piece of wood is a piece of shear bracing. I noticed that the Wing Tube does not butt up against a ‘Stopper’, the WT is actually some 2” too short to meet the nearest rib. So it would seem that during the flights the WT moves and has ‘finally' cut the shear webbing off! I guess the chap that built the plane did not think that the WT would move…
OK; that’s the problem, now what to do about it!?
I decided to correct the original problem and I built ‘Stoppers’ for the Wing Tube in the wing. Simply – I fit two half sized piece of Shear Bracing in (one on either side of the spars), added some triangular stock to have lots of surface area and then glued on a piece of light ply for the face plate of the ‘Stopper’.
I did this in both wings and made sure that there was enough room for the Wing Tube and less than 1/8” of play. (lots of measuring and sanding)
So now the underside of both wings are wide open and looks like H3ll, I’ve gone this far why stop now? I never did like that 1” Checker board pattern – so I cut off all of the covering and recovered the entire bottom of the wings with basic beige and a couple of Black ‘Invasion Stripes’. Simple, but effective.
About this time my Mrs. walked up and asked me why I was here on a Sunday morning and not flying? My explanation did not impress her any more than the time to complete this repair, I started around 6AM and I finished around 2PM.
Hey, the job NEEDED to be done and I was in the zone!
Only minor touch ups to do now and I will be ready to fly with confidence – next weekend!
07-12-2014, 03:47 AM
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You make an excellent point that so many overlook. I can recall several times at the field people have had mishaps on landing and take off where the wing dips n gently cartwheels in, many people give it a quick check over on the outside change there prop then go re-fuel and fly it again and the next thing they know the wing folds or the model suddenly fly's erratically and out of trim due to the servo tray breaking free etc. I always used to inspect my airframes after every Sunday at the field. especially sport and 3d models because we usually throw these around the sky at high speeds and G's. I also believe part of training a newbie to fly should involve teaching them this also by showing them what to look out for after hard landings and so forth. I also believe in keeping a record of repairs on my models and going back and checking them on a regular basis to ensure the repair is holding up. Safety is important in this hobby and sadly is overlooked so often when it does not cost a dime to do any of these checks just an few extra minutes up to an hour a week or month depending how often they fly.
Well spotted bbbair bet your happy now you know what the problem was and I bet your even happier you potentially saved your extra from losing a wing panel in air.
Well spotted bbbair bet your happy now you know what the problem was and I bet your even happier you potentially saved your extra from losing a wing panel in air.
07-12-2014, 11:27 AM
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The RE-MAIDEN was successful!
It did need a bit of trimming... but that is to be expected any time that you remove a servo.
I don't care HOW careful you are you NEVER seem to be able to get things aligned EXACTLY the way they were.
Oh well, on to the NEXT project. (there is always another one. )
It did need a bit of trimming... but that is to be expected any time that you remove a servo.
I don't care HOW careful you are you NEVER seem to be able to get things aligned EXACTLY the way they were.
Oh well, on to the NEXT project. (there is always another one.
)
