EeebeeE
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With those restrictions, you will be hard-pressed to find a 4" FG rocket that will stay under your waiver limits. I suggest you download Open Rocket (free) where you can lay in a design and simulate flights to see what you can use to keep your altitudes down. As far as motor tube goes, There is nothing wrong with using a bigger hole and an adapter, so that if you go to a field with a higher waiver you can let her rip.
Also, you can fabricate a removable dead weight to attach into your rocket to limit its altitude. You just have to make sure your impulse at launch is sufficient enough. I had to do that with my L3 attempt because I was flying on a field with a 9,000' waiver and my rocket was simming to 10,000'. I made a 5-lb. weight that attached to the threaded rods inside the AV bay, which brought the sim down to 8,000'. The rocket flew to 7,900'.
As far as kits go, I'd look at 5.5" kits like the Wildman Jart or Gizmo. The Gizmo is fun as heck to fly and it is rugged. Madcow has a 5.5" Nike Smoke and V-2 that are reasonably priced. With all of these, however you would need to either buy a DD add-on or get creative with a less conventional configuration. My 5.5" Gizmo separated normally with the nose cone and booster at apogee, but I should out the main with a chute cannon in the nose. It worked pretty well. These all have 54mm holes so you can either use a 2-grain 54mm J or use an adapter to fit in a 38mm J motor, which will be just as strong, but longer.
The nice thing about 54mm motor tubes is that depending on the size of your rocket, you can fly up to baby L motors, which can be flown with an L2 certification. 38mm motor tubes limit you to a nearly full J.
Also, you can fabricate a removable dead weight to attach into your rocket to limit its altitude. You just have to make sure your impulse at launch is sufficient enough. I had to do that with my L3 attempt because I was flying on a field with a 9,000' waiver and my rocket was simming to 10,000'. I made a 5-lb. weight that attached to the threaded rods inside the AV bay, which brought the sim down to 8,000'. The rocket flew to 7,900'.
As far as kits go, I'd look at 5.5" kits like the Wildman Jart or Gizmo. The Gizmo is fun as heck to fly and it is rugged. Madcow has a 5.5" Nike Smoke and V-2 that are reasonably priced. With all of these, however you would need to either buy a DD add-on or get creative with a less conventional configuration. My 5.5" Gizmo separated normally with the nose cone and booster at apogee, but I should out the main with a chute cannon in the nose. It worked pretty well. These all have 54mm holes so you can either use a 2-grain 54mm J or use an adapter to fit in a 38mm J motor, which will be just as strong, but longer.
The nice thing about 54mm motor tubes is that depending on the size of your rocket, you can fly up to baby L motors, which can be flown with an L2 certification. 38mm motor tubes limit you to a nearly full J.