I did my Level 3 with a Performance Rocketry Competitor 4 on an Aerotech M1315W. It went 16,345 feet which was the average between the two altimeters a Perfect Flight MAWD and a Perfect Flight HiAlts45K. I used a 30" PML Parachute for the drogue and an 84" Fruity Chutes for the main. It did have internal carbon fiber over the internal fillets as well as a single layer of tip to tip carbon fiber.
I would suggest you fly the flight you want to certify with. It sounds like a 4" (or 3") bird to a decent altitude is your hankering . Just make sure your TAPs are happy with that. Some are happy to certify off the data showing the drogue and main deploying properly, others like to see the entire flight to verify. You can make enquiries to find the requisite TAPs to suit your flight.
Have fun, and good luck!
You mention "CFing" tip-to-tip weren't the fins 3/16 glass?
Yes they were 0.1875" G10 but I'm one to always build on the extra strong side.
I have flew my 4" Broken Arrow 2 times on AT M1297 twice with no problems. No tip to tip or internal fillets. Just used West Systems epoxy.
Love that kit, seen the 5" version fly more than once. Did you build the 4" with a 75mm motor mount?
Yes it has the 75mmt. I think they had 2 versions mine had the 75mmt and the thicker fins.
I did my L3 with a scratch built 4" diameter rocket on a AMW M1350. It flew great to just under 16K and earned me my L3 on the first attempt. That was almost 15 years ago; looking back now the rocket is too long and spindly. If I were going to do it again I would use a single piece of airframe and do out the top dual deploy.
My L3 was a MAC Performance canvas phenolic Radial Flyer 4" on a CTI M1101. Flew over Mach 1 to 13,000. Came down over a mile away.
I did mine on a scratch built. If I did it over I would have used a 98mm mount. https://www.rocketryforum.com/threads/l3-4-inch-black-brandt-scratch-build-success.66990/
Construction? Tracking?
I certified my L3 on a 2.5" rocket. M900 RATTWorks to 27k.
Edward
Airframe and coupler is Hawk Mountain fwfg. Fins are 1/8" G10. Internal fillets are West Systems and chopped carbon fiber. Tracked using a RDF transmitter.
Very cool, max velocity?
Was flutter a concern/issue using 1/8" G10? That's one of mine.
BRB900 and my name and phone number on the coupler. Got a call from two farm boys saying "we have your rocket."Tracking? Surely you could not see it.
If you're concerned about fin flutter, FINSIM is a free download.
It could be depending on the fin shape. Honestly, my L3 fins are probably a poor shape in that regard (similar shape to a LOC Magnum), but they held. I think a mitigating factor was that the overall size and weight kept the speed down to a manageable level. That being said it went Mach 1.3. I've been toying with the idea of ditching the upper airframe and just flying the booster with out the top dual deploy. But I doubt I would fly an M in it in that configuration, due to flutter concerns. I've personally witnessed a minimum diameter 4" rocket fly on a very large N to probably over Mach 2 with 1/8" G10 and no tip to tip reinforcement; so that is another data point to consider. Again, fin shape matters. Any more I like to do one layer of carbon and one layer of S glass, both for minimum diameter and non-MD. For non minimum diameter I like to do the tip to tip on the motor tube and then mount it in the airframe afterwards. That way I get the strength I'm after without having to do a bunch of filling, sanding and shaping on the airframe to smooth it all out.
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