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How to repair this

Old 05-19-2013, 05:58 PM
  #1  
Popriv
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Default How to repair this

Maidened my Mariner yesterday, Flew great once I trimmed it out but got careless on the 5th flight, doing figure 8's in a strong wind, think I got to slow, lost lift and spiraled in. got level and pulled it up a bit just before it hit.

The impact snapped off the engine pod and the prop dug into the turtle deck, This also held the engine up. The OS .60FX was hanging by the servo wire!
The wings were still attached but it split at the glue joint.
Rest of fuse is good.

Q: Could use suggestions on reattaching the engine pod.

1st though is CF laminate on each side running right up into the pod. firewall came out clean so I have good access into the pod.
I'll have to adjust wing joint/slot to fit around whatever I use as laminate. maybe also pin thejoint with CF dowel and epoxy?
Obviously there is alot of stress on this joint but I dont want to overdo it.

I dont think I should try to cut out the old post so I could put in a new, one piece post. So its the pod to the top of the post I have to secure.....

Turtle deck will be an easy repair. May glass the front and paint just the front?

Wing halves are intact. It seperated pretty clean.

Q: How do I get a new spar in there though. not sure about that? how many bays does it have to go. Pluse I'll wrap fibeglass around the finishd joint.


Plenty of power with the .60 on it so a little weight on the repair wont hurt.....





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Old 05-19-2013, 07:19 PM
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Default RE: How to repair this

The mariner is now an ARF right.. i dont think the formally make the kit anymore??

Looking at the pod... you can see how it was put together so I would take that as my lead. Looks like they were two pieces (pod and post) and then joined. I would clean it up so you get a good wood to wood contact.. being sure to keep the thrust line the same, remvoe the covering on both sides of the bottom of the pod and use tri-stock for extra support runing from the front of the post to to the end of the support on the pod, rouding the front off and fairing the rear of the tri-stock. If yoiu have access inside..with the post being up front... you can add add'l tri-stock support there as well on each side as I would think the posat rises up past the bottom of the pod. None of this will add much weight.

For the wing... I would pull the covering back sevral inches such that I could re-iron it back down keeping the same look. The best way to repair a wing regarding joiner damage, in my opinion, is to open it up for good access and do it correctly as oppoed to trying to clean out the area and slipping a new one in with epoxy. You won't be able to get enough epoxy where you need it.
Old 05-19-2013, 10:14 PM
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Default RE: How to repair this

For the pod I would do as Mike says. On the wing I too would peel back the covering but I would just epoxy the two halves back together and clamp them tight. The covering has to be peeled enough to get the clamps on. If all you fly are ARFs you may need to borrow some tools from a builder, clamps and iron but it isn't a hard repair. If you have a friend that builds they may also have some covering in the colors needed and be able to show you how to do a nice patch job. Orange, red and black are colors most of us have on hand, not to mention blue, white and yellow.
Old 05-20-2013, 01:17 AM
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Default RE: How to repair this

I think the post ran up into the pod in one piece. It didn't just separate at a glue joint? The post snapped at the bottom of the pod.
Sounds like you are suggesting just gluing the broken area and surrounding it with tri stock? I don't know if that will be strong enough?
I have plenty of tools and building experience. I'm just not sure what will make the pod structurally sound again? It is a high stress area.
Starting to see how I could build up the top of the post and create a flat area that the pod could glue down onto. My first thought was the post has to go through and into the pod like it was originally? Hmmmmmm...

Not as concerned with the wing although I've never tried to replace a spar. I guess my options here are to peel pack the covering, put in a short spa in the first bay glue it together and wrap the joint with glass? OR. Open the wing up on the bottom and cut in a new spar then close it up again.

Covering things up and making it look pretty after the repair won't be a problem.

Just don't want the pod to break off or the wings to fold up on me after the repair!

Also thinking of attaching a thin cable from the engine mount, down the post and into the fuse.
In the event of another bad crash I don't want the engine breaking off and sinking. Came close this time.
Figuring it would hang in the water From the cable if everything else broke ?


Thanks ! The suggestions help.


Steve
Old 05-20-2013, 03:30 AM
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Default RE: How to repair this

If it's one piece.. that's a perfect break. The piece remaining on the pod second support. THe post going up into the pod with bracing on four contact points and the rear support will be plenty strong. Don't know if I agree with just butt gluing wing panels together??

for the pod.. what I was suggesting was the pic with filler pieces iniside the pod front and back between the tri-stock where they run fore and aft of the post... and on the bottom, front of the post. If you look at how it was originally designed.. doesn't look like there was support at all. I cannot tell if the post went vertical way up and was epoxied d tied to what looks like a vertical support in the pod itself. I doubt it or the pod wouldn't have come apart so cleanly. The rear support piece running down the rear of post t is the main support... the tr-stock offer lateral stability. Does the rear curved support run up inside the pod at all. Seems like no or there wouldn't be much for a tank?

Apologize.. just re-read your post.. "Pod snapped at the top".
You need to see how much is up inside and then remove it.
I would then do this along with the pic on the left....dovetail a new piece, being sure to extend it up however far the original was ...face the sides with light ply, epoxy, clamp along it's length, then round the front and feather the rear a bit..
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Old 05-20-2013, 04:28 AM
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Default RE: How to repair this

Good morning Steve The more critical of your repairs is the wing separation so that is the one I am going address. You cannot but glue back together and just fiberglas any thickness that is an inflight failure just waiting to happen. Now the problem is that it is very difficult to attempt to remove an original spar that is inlaid between a top and bottom spar as well webs either front or rear or both for a box section.

The best solution to at least have the original strength or better is surgery, removing sheeting (far easier if top and bottom) and cutting a spar doubler. You can use just a single front or rear as well as both for ultimate strength and of course if you choose both you can use a thinner doubler.

This doubler should go out as far as the original and be the full depth of the wing no less. Use only birch aircraft plywood. The affected first and second bay ribs will need to be cut back a quarter inch or so and after the doubler(s) are epoxied in the small gap is filled in with sheet of the same thicknerss Finally the resheeting is done.
Old 05-20-2013, 06:38 AM
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Default RE: How to repair this


ORIGINAL: KitBuilder

If it's one piece.. that's a perfect break. The piece remaining on the pod second support. THe post going up into the pod with bracing on four contact points and the rear support will be plenty strong. Don't know if I agree with just butt gluing wing panels together??

for the pod.. what I was suggesting was the pic with filler pieces iniside the pod front and back between the tri-stock where they run fore and aft of the post... and on the bottom, front of the post. If you look at how it was originally designed.. doesn't look like there was support at all. I cannot tell if the post went vertical way up and was epoxied d tied to what looks like a vertical support in the pod itself. I doubt it or the pod wouldn't have come apart so cleanly. The rear support piece running down the rear of post t is the main support... the tr-stock offer lateral stability. Does the rear curved support run up inside the pod at all. Seems like no or there wouldn't be much for a tank?

Apologize.. just re-read your post.. ''Pod snapped at the top''.
You need to see how much is up inside and then remove it.
I would then do this along with the pic on the left....dovetail a new piece, being sure to extend it up however far the original was ...face the sides with light ply, epoxy, clamp along it's length, then round the front and feather the rear a bit..

Great picture. I like the way you dovetailed the extension onto the original post. laminate the sides and extend it all the way into the pod as the original was. Since the firewall already pulled out access will be easy.. looking good. thanks
Old 05-20-2013, 06:45 AM
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Default RE: How to repair this


ORIGINAL: JohnBuckner

Good morning Steve The more critical of your repairs is the wing separation so that is the one I am going address. You cannot but glue back together and just fiberglas any thickness that is an inflight failure just waiting to happen. Now the problem is that it is very difficult to attempt to remove an original spar that is inlaid between a top and bottom spar as well webs either front or rear or both for a box section.

The best solution to at least have the original strength or better is surgery, removing sheeting (far easier if top and bottom) and cutting a spar doubler. You can use just a single front or rear as well as both for ultimate strength and of course if you choose both you can use a thinner doubler.

This doubler should go out as far as the original and be the full depth of the wing no less. Use only birch aircraft plywood. The affected first and second bay ribs will need to be cut back a quarter inch or so and after the doubler(s) are epoxied in the small gap is filled in with sheet of the same thicknerss Finally the resheeting is done.
Thanks John, I agree. I dont want the wing folding up on me. So I will cut back the sheeting ( top or bottom? ) to expose the existing spar. cut away the ribs and laminate a new spar to the front and back of whats there. ( better Idea when I get in and see it ) then repair the ribs I cut and replace the sheeting.
The new spar will not be boxed in like the original! just epoxied to the frontg and back of the original spar box.
So, open it up and rebuild the spar area.

Now it looks like the wing will be the more difficult part of the rebuild.. I have until October when we have our next big float events.. lol

thanks again.
Old 05-20-2013, 03:29 PM
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Default RE: How to repair this

took the pod apart and found two main structures as shown in my drawing. these two parts were glued together with laminate on each side. It is the laminate that broke.

Have to decide if I can remove the broken laminate from the pod structure? of just make a new section of the pod like what I drew. Probably make a whole new pod?
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Old 05-20-2013, 06:03 PM
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Default RE: How to repair this

I was thinking I had to remove what was left of the doublers in the pod, ( the laminate that snapped)
I can double up on top of the broken ply. just have to cut a slot in the bottom of the pod to accept the new doubler.
This will duplicate what was done originally.

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