My GP Cap 232 27% Experience……………

I was in the market for my first large scale model and settled on purchasing the GP Cap 232 27%. GP have a good reputation in the market place and with spare parts readily available through tower hobbies, I thought it would be a good option. I also wanted to run a 50cc engine and reading this thread, there are numerous references to people running a DA, or DL50 engine with this model without a problem even though the ceiling is 43cc according to GP’s documentation. I decided to run a DL50 engine in mine.

The set up I was running was;

Servos: JR9411 for all control surfaces and 8231 for the throttle
Receiver JR921
Engine DL50
Prop Bolly 20x10

While I am no expert in relation to building larger scale models, during construction, I was somewhat surprised by the size of the joiner that is used to join the two wing sections together. For a 27% model that will run a 43cc engine, it appeared rather thin to me and was constructed from hardwood (approx 6mm thick). GP on there website make specific reference to this to keep the weight down rather than using an aluminium or carbon joiner.

The model went to the field yesterday for its maiden and I had arranged for the club instructor to take it up for its first flight. The machine powered into the air with no trouble what so ever. It had completed probably three circuits of the field in near level flight between half and 3/4 throttle while the instructor adjusted all the trims. All of a sudden there was an almighty crack and immediately it became apparent that something had let go in the wing at the join.

I thought for sure the model would be lost. Through an amazing piece of flying, the instructor managed to nurse the machine down onto the ground using rudder and elevator only. The wings had folded upwards about 6/7 inches at each tip. Our immediate thought was that the glue joint had given way but on inspection it appeared to be quite different. The glue joint was in tact however the timber ribbing on each side of the wing had sheared, the spar was broken, and the plate that holds the wing bolts was split in half.

The only thing that was holding the wing together was a cable tie that I had wrapped through the aileron lead holes which I was using to stop the cables from falling back inside the wing, the dowels at the front which appeared to be in tack, and the wing bolts held the back of the wing together. When we got the model back to the pits, the wing bolts were removed that wing fell in half and was held together with the cable tie only. I am incredibly lucky to still have this model, The fuse is in perfect condition however the wings will need replacing as I believe it would be risky to repair them given the potential value of the loss should they fail again in flight.

If this machine was performing any sort of aerobatics at the time of the failure, there is no question I would have been taking home a pile of tooth picks as I am sure the stress on the wing from the recovery would have broken the wing off entirely.

I have attached the photos for you guys to look at. You can see that little cable tie that I referred too. I would welcome your views although I am of the opinion it was a product failure. I do believe that the experience raises questions as to whether the wing joining method is appropriate for a 27% model running 50cc engines. Especially this is promoted as a performance model.

On a side note, the wing failed with a DL50 running at 50% to 75% capacity in near level flight. I would suggest at a 43cc engine running in full aerobatic mode would have created a similar occurance but with a catastrophic outcome.

I intend to get this fixed however I am inclined to change the joiner to carbon or aluminium and remove the DL50 for its next flight

Has anyone else had a similar issue with this model?