I want to be able to launch E engines, but apparently they require a different launch controller and pad. The only differences I can find between these and the accesories for A-D engines are that the controller has a longer wire and the blast deflector plate is larger. However, I usually launch over concrete anyway, and longer wires can be substituted for with copper wire, I'm sure. So do I really need to spend $40+ for all the extra accesories?
No.
Jerry
The "E" engines use the same type of igniters, so you don't really need a different controller - extending the wires should work fine. I don't know what gauge wire Estes supplies with the original comtroller, but if you get some heavy gauge (#16) speaker wire or "zip cord" it should have ample current capacity.
-dave w
No, just replace the igniter wires with 30 feet of zip cord (more than adequate for these current requirements), or just make up some "extension" wires and clips, and hook your current launch controller to these, being careful that the clips don't touch each other and cause a short.
The only reason for the longer leads is to satisfy the NAR safety code requirement for model rockets greater than "D" impulse (30 feet away from the launch pad, vs.
15 feet for 'D' and under).Whether or not you need a bigger deflector plate (or launcher for that matter) depends on the physical size of the rocket you'll be launching. I wouldn't, for example, launch a Maxi V-2 from an Estes 'starter set' pad with a short 1/8" rod. But a suitable pad for such a rocket can be scratch built from $8 worth of parts from Home Depot.
#!*@ Looks like they changed that rule recently. The dividing line used to be at 30', which would allow the wimpy E9/E15 motor, as well as a cluster of
3 C6 motors in an old Ranger or the like. Now it just says D or smaller. Does thaat mean I can fly a cluster of D motors, or say 6 C motors with a 15' cord?No, there is no difference in the launch system for a D12 or an E9. All you need is 15' more wire. IMHO every plastic launch controller on the market is junk. The only possible exception is the Quest pistol-grip unit that uses 9v batteries.
For the past 3 decades, I've made my own, or heavilly modified an existing controller. I had a Solar launcher for many years, and about the only stock pieces were the 2 gray plastic body halves. IIRC I replaced the bulb with a buzzer, hacked the interior to hold 6 AA Nicads, added a charger pigtail, and replaced the wire with 30' of 18ga zip cord. Since then I've been using a couple relay launchers.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
The harder you squeeze the higher it goes.
Jerry
Whoops. Unit error. The dividing line used to be at 30 NEWTON SECONDS! This probably got changed to D motors when the code was rewritten and "simplified" just over 2 years ago. BTW, I double checked and it does say "D motors" (plural), so a cluster of D motors is now 15' legal. Until you have
6 of them when the safe distance jumps from 15' all the way to 200' :-(
All distance numbers in the SC are wack.
200 feet for 120ns Bob ?
Art
No, it's worse than that. It's 200' for about 100 NS.
Why? 6 D12s have 126.6g propellant, making it a HPR model and requiring a waiver. And since it's clustered, it's a complex model and NFPA 1127 requires a 200' safe distance. Ditto for a cluster of 4 E9s, at 143g.
Take away one of the D12s and the safe distance is 15' thanks to the "simplification".
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
Weren't the claimed propellant masses alot lower at one point. I seem to recall carefully calculating that a USR Hi-Test 2225 (2 stage 3 cluster D12) was under 125g with 3 D12-0 to 3 D12-7. Might be the zeros that bring it down.
Jerry
Nope. Your 2 stage D rocket was always exceeding the model rocket propellant weight limits when using 6 Ds. Both old and new weight limits.
5 D12's was the upper limit but now you can do 2 D12s and 2 E9s and it gives you a bit more while still staying under the limit.-Fred Shecter NAR 20117
-- ""Remove "zorch" from address (2 places) to reply.
Makes lots of since to me bob. lot-of-crock, he he...
so I can hide away (200') for 4 e9s and be 100' closer for a nice J-550 flight right ?
"I'll glady pay you tuesday for a motor today", ArtU
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