[SARPLT]

I thought I would share my experiences on yet another rebuild that ended up on work bench, the resurrection of an LX F4 Phantom (twin 70mm) orange addition. This particular model was owned by one of our club members who unfortunately had some difficulty with the aircraft on the maiden flight, resulting in an impact into a corn field last summer. The model was passed to another member who attempted to put it back together. I was asked to help out with the next flight but after having had a quick look at the aircraft it was pretty evident that there was no way it was going to fly again anytime soon. Having a soft spot for the Phantom, as it is one of my favourite aircraft, I was offered the opportunity to resurrect this legendary 1960s era versatile fighter. Although I have two other ones I could not resist as this is a huge model. And so the project begins.

The first step was to give the model a good once over to see what shape the airframe was in and what electronics worked. With the exception of the nose which seemed to take the majority of the impact on crash the rest of aircraft is in good shape as it did not have much flight time on it. On power up both ESCs (50 amp) armed but only one EDF (70 mm 2100KV) spooled up, all servos worked but none of the retractable gear is operational. The model has a split full flying stabilizer but the linkage and housing to the fuselage is rather flimsy with lots of play and the angle of attack on each side is different by about ¼ inch so that will need to be further investigated. Also all the linkages are very flimsy with a weird setup for the flaps which has the control linkage running right across the retract struts with multiple bends so that will need to be corrected. The aircraft comes with leading edge flaps but the linkage looks like a nightmare to setup and after having had several coats of additional paint applied to everything including the linkage it will be difficult to get these to operate smoothly again so I will likely remove these. The next step is to gut everything before I proceed with the rebuild.

I will keep you posted.

Marty

[Cougar429]

I watched a few videos of this one and although it looks like it would have lots of potential have to agree the linkages look pretty weak. It also looks like it avoids the typical graveyard drop a lot show on final.

Some good fan units would likely make a big difference in performance and sound, (the originals remind me too much of the dentist!).

Look forward to see what you do with this one.

[Ferg]

I look forward to seeing it in the air.

[SARPLT]

With everything taken apart the first step was straighten out the nose. I made a jig with two pieces of wood cut down to fit into the canopy slot and the bottom gear area. Before I installed these two pieces I steamed both sides of the fuselage using the kettle until the foam softened and expanded to enable me to install the two pieces of wood. Once the foam cooled and hardened most of the irregularities were taken out with the exception of a slight offset to one side where the original repair had been done. This was corrected by making a couple of vertical cuts in the fuselage just in front of the intakes and gluing the joint back together with epoxy. The foam removed doing the cut was sufficient to straightened out the fuselage. This was confirmed by running a line from tail to nose. With the overall nose straight I had to correct the small bulges in the side that had occurred from the steaming process. These were easily taken out using a long sanding block with 60 sand paper. The only problem with doing this as we all know is the foam becomes fuzzy, not suitable for any filler as it will just crack as the foam flexes. One of the tricks I use is to spread some 15 min or 30 min epoxy over the exposed foam with my fingers until the whole area if covered with a very thin coat. Once it sets up the fuzz becomes hard which is easily sanded and you now have a rigid hard surface that is ready for your filler. This does not add much weight and actually adds some strength to the area as well. For those that may be unaware, rubbing alcohol is a great way to remove any epoxy residue from your model and fingers before it sets up. I always have a bottle near when using epoxy. With the fix complete I coated the whole nose with a thin coat of filler. Next step is to do some sanding to reshape the nose.

Due to the the horizontal stab sloppiness it was apparent that I had no choice but to cut into the tail to further investigate. The design includes a plastic spacer that is glued in on each side of the fuselage that extends into the tail where the plastic control arms slide over and rotate. The pressure from the sides of the fuselage keeps these two control arms on their spacers. This design allows each stab to flex in all directions due to the flexing of the foam. I tried to strengthen the area with epoxy but no change. After reading another forum there was a recommendation to add another spar ahead of the rotating axis to basically box in the two stabs creating a solid structure. I decided to do this so I cut and shaped a metal rod to fit the shape of the two stabs angle and slotted it into both stabs. With a small slot cut into both sides of the fuselage this new spar is free to rotate through the fuselage. Although it is not very scale it significantly reduced any flex in the stabs. Hopefully the minimal flex that is left can be taken out with the CF rod that I will be putting over the control linkage. More to follow.

Marty

[Cougar429]

I would bond a small plastic sheet to the stabs to hide the slot and paint it the same as the fuse to make it basically invisible in flight. Did something similar with the canopy release pin slots on Rare Bear.

[SARPLT]

Thanks Gary but this will not be an issue as I will fill the gaps once the rods are glued in. I had a chance to strip the wings down but it did take some work to get them off the fuselage. The main spar is a single aluminum tube that runs through a larger aluminum tubing in each of the wing halves and fuselage. These were ceased in each other resulting in me having to twist the wings to get them to pull out of the fuselage. I am going to replace these with a carbon fiber inner and outer rod. All the leading edge flap mechanisms and all servos were taken out. I am going to re-position the flap servo closer to the wing trailing edge. After a rough sanding the LE flaps were glued onto the wing. Next step is to fit the new retracts into the mounts.

[NDW]

Martin,
I have an LX A-10 coming into the shop that has been munched pretty much like your phantom. Your rebuild gives me hope to rebuild it not strip it for parts. I'd like to order a new A-10 basic airframe but the $400' US dollars is alittle to steep for me.

D.

[4stripes]

Always nice to see a crashed plane be made flyable again! Foam is easy to work with and you have nothing to lose.

[NDW]

Eric...... Zen thinking at its best....

D.

[SARPLT]

Nelson
I have rebuilt about 9 aircraft now, some that have had a catastrophic event and I can tell you that you can pretty much rebuild any foam model. If all the parts are there it is a bonus otherwise all you have to do is pick up some foam and carve the replacement parts. I get great satisfaction from resurrecting a destroyed model. I continue to learn more building techniques through everyone's build threads so that is why I like to post my experiences. I hope you start a thread for your A 10.

Cheers
Marty