True-Course
Active Member
- Joined
- Dec 8, 2012
- Messages
- 27
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I own s/n 6970, a beautiful 1941 J3. It has an A75 engine, metal prop and everything else is, seemingly, unmodified.
Here's the puzzle - it is not placarded for rear seat solo. When I (170lbs) fly it solo from the front, with full fuel, the stick is neutral but the trim is right at the top of the screw, almost full nose down. That means that with rear passengers onboard I could conceivably be out of nose-down trim.
We have looked at this from all angles trying to figure it out with zero success. Here is what we've checked:
1. Trim works perfectly.
2. Yoke on the trim screw is right side up (V pointing down).
3. We used a digital angle gauge and placed it on the elevator of a normal J3 with the trim in the middle, then placed it on the elevator of mine at the "neutral position" (almost out of nose down trim) - it was within 1 degree.
4. Trim pieces where the windshield and the wing meet are tightly and neatly placed.
5. Engine mounts are in good shape.
6. The Cub flies beautifully, balanced and true. Simply out of nose down trim if you needed it (which you might with a heavy passenger in the back)
7. The lower longerons appear to be straight, the empenage has a ski compartment so it's hard to check the longerons but the skins are straight and without wrinkles.
8. Logbooks have no mention of anything. They start in 1946 and there was a ground loop in the 70s. Historic records I found show it was ground looped in 1943 and fixed at the factory (which was fairly rare in those days).
What are we missing? we cannot figure this one out. I'd appreciate any insight into the problem.
Best,
Alejandro
Here's the puzzle - it is not placarded for rear seat solo. When I (170lbs) fly it solo from the front, with full fuel, the stick is neutral but the trim is right at the top of the screw, almost full nose down. That means that with rear passengers onboard I could conceivably be out of nose-down trim.
We have looked at this from all angles trying to figure it out with zero success. Here is what we've checked:
1. Trim works perfectly.
2. Yoke on the trim screw is right side up (V pointing down).
3. We used a digital angle gauge and placed it on the elevator of a normal J3 with the trim in the middle, then placed it on the elevator of mine at the "neutral position" (almost out of nose down trim) - it was within 1 degree.
4. Trim pieces where the windshield and the wing meet are tightly and neatly placed.
5. Engine mounts are in good shape.
6. The Cub flies beautifully, balanced and true. Simply out of nose down trim if you needed it (which you might with a heavy passenger in the back)
7. The lower longerons appear to be straight, the empenage has a ski compartment so it's hard to check the longerons but the skins are straight and without wrinkles.
8. Logbooks have no mention of anything. They start in 1946 and there was a ground loop in the 70s. Historic records I found show it was ground looped in 1943 and fixed at the factory (which was fairly rare in those days).
What are we missing? we cannot figure this one out. I'd appreciate any insight into the problem.
Best,
Alejandro
