36" for the chute. My PML AMRAAM-3 goes on a PML 48", and it drifts a lot (recovery weight 3.7lb). As for the second flight, the H148R is a great motor. Makes for absolutely beautiful flights. Fast and high in a bullpup 🙂

Bob,

I've built two bullpups (I won't tell you why I had to build the second one).

I put 3 ounces of nose weight in the first and 2.5 in the second. I use the 36" parachute with no problems at all - I would just stick with it. My level one was with the BP. It took me two attempts because the parachute tangled and did not fully deploy on the first try. Perhaps the smaller chute would help in this area too.

My two cents on the stability--- use the additional noseweight and please, please, please make sure those forward fins are straight. The newer version of the kit with the fin dados already cut make it pretty easy.

Chris and Ed,

Thanks for the suggestions. I guess I will stick with the 36" chute. I'm just nervous about popping off one of the forward fins from too hard of a landing.

Ed- You're right about the dados making it much easier to line up the forward fins. They are as straight as I could reasonably make them.

Thanks again for the help and encouragement. See you on Saturday.

As long as you remembered to scuff up the tube and fins thoroughly before gluing, you're fine (100 grit at the finest). Never had any problems with a well-scuffed tube 🙂

Bob,

Congratulations on the level one cert!

It was successful?

Congrats then 😀

i dont understand how the forward fins count in a cert flight... they are freakin pure cosmetic on a BP and a BBX my word to the wise is... i mean its only a H motor which isnt that expensive but sometimes you can bring some CA out when you retrieve and get those dumb front ones on... if one is kinda laying right next to the rocket(shh i didnt say that)

but if you put them on right... 15 min epoxy and like chris said 100 grit sand paper scuffing they will hold.... dont worry about the 36 inch chute, its all good! we have launced a small endevour on a J350 and it came down on a 36 inch with no worries, the praire is a little forgiving sometimes our little rocket went mach 1.2 soo thats pretty fun time and everything held just fine.

oh yeah launch lugs do count! when we mount them on a QT tube we lay a strip of fiberglass over them and 15 min epox them after the area is nicely scuffed, I failed my level 2 cause of silly launch lugs so make sure they are on!

All I can say is that if you're not using rails on birds with 38mm motor or above, and even 29mm birds, you're not up to speed on current best practices. While the club maintains a bunch of launch rods up to 1/2" diameter, anything that would demand a 1/4" rod or above should be fitted out with rail guides and flown off a rail. Rod whip and other issues are all moot when flying off a rail.

Warren

i agree 🙂 RAIL LUGS are where its at! some rocket clubs dont have a rail set up so i put launch lugs and rail lugs on some of my rockets(Watermelon being one of them) basically you screw the rail button in and JB weld it on... ( i havent lost a button yet with that method) but all you fancy lads with nice piston ejects you cant really do that so you might try the pml longer resin lugs with some JB weld and that should hold good also. but i wouldnt do that method if i was trying to certify IMO too risky even though JBweld is some serious epoxy putty!

I have flown 4" birds up to 15# with Acme rail guides "merely" glued on with JB Weld.

Warren

With rail buttons, I simply screw them in (using threaded inserts), with no glue required. That makes them easy to remove and replace if necessary, and I have had no trouble at all with using this method on up to 30lb rockets so far (my deuce).