I was talking to Steve Fitton the other night on the phone and we got to talking about what I would do to take the T-Rex to the "next level" considering the way the first production run went (it was really much better wood than I anticipated). If I were to take the standard ARC to "Nats" level what would I do? It was a pretty short list really.
1. Add the ply doubler extensions at the trailing edge if your version does not already have it . The latest versions will have this installed.
http://stunthanger.com/smf/index.php?topic=16383.02. Thoroughly soak the fuel tank area (all of the joints) with thin CA. Paint the entire area with thinned epoxy. Glass the F2 joint to the side walls or fillet with epoxolite or similar. Also do the BACK of F2 (on the wing side the same). Add 1/4" lite ply tripler to the back of F2 at the top of the wing airfoil (to butt strengthen F2 from the top). Soak all that in CA.
3. Thoroughly soak the end grain of the lite ply F2 all along the radius that will eventually be the bottom of the plane. Just keep soaking it until it will not take any more CA.
4. Add 1/32" ply for 1" at the flap root over the flap horns. Sheet the stabs and elevators (as is) with 1/32" light balsa (per Bob Reeves). Sheet one side at a time, allowing the flaps to dry on a flat board while the whole thing is weighted. Butt join ply to new sheeting. Glass the horn area with 3/4" glass at ply and balsa joint.
5. Soak the flap and elevator control horn holes with CA and re-drill hole slightly oversized (so the horn is a little loose). Join flaps and elevators on the flat board before assembly. Use Gorilla glue as it will fill the hole and gets glues to steel better than anything. The slop in the hole will make it easy to get everything flat. Weight it down while it dries.
6. I would buy new pre bent control horns and pushrods (complete with turnbuckle link in the back) from Tom Morris. Buy
the SHORTER 1.25" horn for the front and the matching slider horn for the back. Tom has all the dimensions I have been told.
7. Place each wing half on a flat board and weight down the trailing edge (or clamp down using a full length piece of hardwood on top). Add vertical shear webs to the trailing edge full length and to the high point of the wing spars out about 5 bays. After this the wing will now be straight and locked in straight.
8. Join the wing halves in the same manner on the flat board per typical foam wing joining (I use masking tape to join and then lay the whole thing on a flat board and weight it down until the joint is dry.
DO NOT USE THE JOINERS!!! Glass the wing joint after gluing with 1" glass tape as per foam wing (go right over the bellcrank mount and nut). After installing the wing in the fusealge use several layers of 3/4 oz glass faired out out (larger to smaller and smaller) at the cradle joints (some carbon tow inline to the fuselage over the joint might be even better).
9. Take the unfinished stab and note if it is flat. If not, give one coat of Polycrylic and wait until it tacks off (it will take about an hour or less). Place on teflon sheet, wax paper, or old Monokote backing on a flat board and place non stick surface on top. Weigh the whole thing down. Let it dry a week. When you remove the stab it will be hard as a rock and flat as a board. Finish as normal with whatever you like. If you use film you may have to put a few coats of Balsarite over the PC. Do not film on the PC, especially high temp film. All other paints will stick great to PC.
10. Re-bend new gear wires from US music wire to suit my propeller size.
11. Use Dave Brown nylon engine mounts, or better yet OS Max aluminum mounts. Use Sullivan hard 6 or 8 OZ tank only. Cock the tank a minimum of 1/4". Mount the tank as far inboard as possible. I use velcro to mount the tank.
12. Glass the nose 3" past leading edge with 3/4 oz glass. Do two layers on cowl hole. WRAP THE GLASS ALL THE WAY AROUND TO THE INSIDE OF THE ENGINE COMPARTMENT. This is for the finger abuse the nose opening takes choking the engine. It is not for strength.
13. I would really like to get a magnet cowl retaining system like Bob Branch used for his electric but I am not sure this would work for IC engines.
14. Cover all open bays with SLC film. The film only needs to be about 3/4" larger than the open bay.
15. Cover whole plane in 1/2A silkpan and nitrate dope (I might use Sig Plyspan again, it is so smooth).
16. Spray two coats of nitrate with zinc stearate from Randy Smith and a little talc. Sand.
17. Use one coat of Sherwin Williams Ultra Fil on spots that appear to have trouble (fillets and such).
18. Paint to preference.
That's about it. Not a lot of work or extra expense really. Should add about an extra 2 oz. I see no need for other mods.
PS: If you do not accurately measure the CG you cannot trim the plane. Period.
Topic: Getting Serious with the T-Rex (Read 7276 times)