Woe is me, but might as well give the VAF brain trust's mechanical engineering neurons a tickle over the long weekend.
Due to a tear in the spacetime continuum, the trailing edge of my -9A's right flap was bent during pushback into the hangar when an unauthorized tool chest suddenly materialized in its path. (That's my story and I'm sticking with it! )
The T.E. distortion was limited to the most-outboard bay. (See the poor picture--in all senses of the adjective.) AEX wedge bent downwards, double-flush TE rivets in the vicinity distorted, and up visible gaps between the skins the wedge, and the outboard rib opened up. The bottom skin creased to a greater extent than the top skin in the picture. Every other part (especially the ribs) is undamaged. Nevertheless, I don't think trying to unbend the TE is likely to succeed, aesthetically or structurally.
All right. Denial, bargaining, depression, and all that duly observed, comes acceptance and a plan to move forward: Instead of de-riveting the top and bottom skins and replacing them and the wedge entirely, I came up with this idea for a repair, and sent it up to the mothership for their opinion. (I know, the dwg shows the outboard end of a left flap, so please apply your mental mirror as required. Neither the dimensions nor details of the depicted ribs are to scale.)
I'm not sure about the number of rivets for the joint plate. AC 43.13-1B (if I'm reading table 4.9 correctly) calls for 5.2 3/32 rivets per inch along a lap joint between 0.020" 2024-T3 sheets. That seems like a lot more than one sees in other lap joints on the RV-9A (e.g.: the wings' inboard to outboard lap joint; forward fuselage to tailcone joint). I'm also not sure about additional reinforcement of the butt joint between the new and original AEX wedge. Structural epoxy between the top skin, wedge, and bottom skin, say? I suppose a ~12" long "vee" of .020 applied to the trailing edge wouldn't be much of a disturbance to airflow over the TE. Could be match drilled to the TE rivet holes in the original skin, then dimpled in assembly with the underlying counter-sunk AEX wedge and dimpled skin serving as the female die.
Van's support got back to me Friday, 31 August, but the Chief Engineer was already out for the Labor Day holiday. They suggested two other options: (a) buy the parts to build an all new right flap; (b) buy a "factory second" QB flap. Evidently, there are cosmetically unacceptable but completely airworthy QB flaps in stock. Mr. Lock himself does the pricing, however.
So, while helpless laughter may break out at KUAO and its environs Tuesday morning, what say ye VAFers: is this an acceptable repair, and if not, what could make it so?
Due to a tear in the spacetime continuum, the trailing edge of my -9A's right flap was bent during pushback into the hangar when an unauthorized tool chest suddenly materialized in its path. (That's my story and I'm sticking with it! )
The T.E. distortion was limited to the most-outboard bay. (See the poor picture--in all senses of the adjective.) AEX wedge bent downwards, double-flush TE rivets in the vicinity distorted, and up visible gaps between the skins the wedge, and the outboard rib opened up. The bottom skin creased to a greater extent than the top skin in the picture. Every other part (especially the ribs) is undamaged. Nevertheless, I don't think trying to unbend the TE is likely to succeed, aesthetically or structurally.
All right. Denial, bargaining, depression, and all that duly observed, comes acceptance and a plan to move forward: Instead of de-riveting the top and bottom skins and replacing them and the wedge entirely, I came up with this idea for a repair, and sent it up to the mothership for their opinion. (I know, the dwg shows the outboard end of a left flap, so please apply your mental mirror as required. Neither the dimensions nor details of the depicted ribs are to scale.)
I'm not sure about the number of rivets for the joint plate. AC 43.13-1B (if I'm reading table 4.9 correctly) calls for 5.2 3/32 rivets per inch along a lap joint between 0.020" 2024-T3 sheets. That seems like a lot more than one sees in other lap joints on the RV-9A (e.g.: the wings' inboard to outboard lap joint; forward fuselage to tailcone joint). I'm also not sure about additional reinforcement of the butt joint between the new and original AEX wedge. Structural epoxy between the top skin, wedge, and bottom skin, say? I suppose a ~12" long "vee" of .020 applied to the trailing edge wouldn't be much of a disturbance to airflow over the TE. Could be match drilled to the TE rivet holes in the original skin, then dimpled in assembly with the underlying counter-sunk AEX wedge and dimpled skin serving as the female die.
Van's support got back to me Friday, 31 August, but the Chief Engineer was already out for the Labor Day holiday. They suggested two other options: (a) buy the parts to build an all new right flap; (b) buy a "factory second" QB flap. Evidently, there are cosmetically unacceptable but completely airworthy QB flaps in stock. Mr. Lock himself does the pricing, however.
So, while helpless laughter may break out at KUAO and its environs Tuesday morning, what say ye VAFers: is this an acceptable repair, and if not, what could make it so?