Rocketcamper123
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- Joined
- Jun 21, 2020
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I dont want to take this thread off course however I disagree, T2T can be required for any size build. I don't think you can make the decision based off of the motor casing diameter as there are multiple factors that go into accounting for fin flutter, with motor characteristics and fin profile being the 2 major contributing factors. You could be flying a moon-burner and have a MD rocket with low acceleration but designed for high altitude flights in which case T2T is likely not needed however you could also have a very aggressively burning motor which will have drastic effects on the rockets acceleration. In such instance T2T may be required to prevent fin flutter no matter the material choice and adhesive used. I've had a 38mm flying case using the Loki K1127 shred on me using an aerodynamic fin profile with a span of about 1.4" which used loctite E120-HP for the properly sized fillet. This rocket accelerated to over 90G in less than 2sec and finally shredded right at max Q 11k up. While yes T2T is not always needed its important not to just rely what you think, rather do the analysis to ensure that the construction is adequate. I know that some obviously may not go as in depth into analyzing stresses on basic "daily flier" however in this case where it's a high performance MD rocket it should be part of the design process.
i think it is entirely possible to build a 98mm min diameter with the n5800, o3400, ect.. using all composite materials without any metal and without tip to tip. it just takes the right design. same goes with a 54mm with the loki 54mm M motor. tip to tip is added insurance but not required. i have built both 75mm and 98mm minimum birds that have exceeded mach 2 without tip to tip and were short as possible birds and recovered