Introduced in 1970 in a sales flyer included with V10, #2 of the Model Rocket News.
The original Estes BT-55 based Goblin was a "FREE" or Bonus kit. If your order totaled a certain amount, you could pick out a listed (free) kit at no extra charge.
It became a regular catalog model in 1972 and retailed for $2.50.
The Goblin kit was catalog number K-55, later designated number 1255.
Designed by Wayne Kellner.
The Goblin design was made for the new D13 motors. The D13 motors were slightly downgraded in power after many CATOs to the D12 you have now. I had a few "blow-through" fireballs using the first D13 engines.
At first, the 24mm D13-5 was a recommended engine. Later catalog listings recommended the D12-7. You could fly the Goblin using 18mm engines with a 20/50 adapter.
I did a build of the BT-55 Semroc clone kit a few years back.
To see that build, CLICK HERE
Here's the parts from a later Estes kit. The original 1970s version didn't include clay nose weight.
The copy of instructions (K-55 version) found on the JimZ site indicates the nosecone was balsa and no nose ballast was included. If nose ballast had been used, it probably would've been those disc-shaped metal (lead) weights.
ReplyDeleteHi Naoto, True! Things seem to be over stable these days. I still have a few of those round lead weights.
DeleteOne advantage (aside from easier finishing*) of the plastic over a balsa nosecone is that the plastic nosecone is generally hollow where the balsa one is often solid. Being hollow allows you to put the ballast closer to the tip than with a solid one (where you're apt to end up putting the ballast at the base of the nosecone) -- meaning that you'll require less of it to shift the CG forward.
ReplyDelete* assuming the plastic isn't something like polypropylene -- the usual glues and paints don't adhere.
This rocket has always been a personal favorite of mine. More for the theme than anything else. Glad to see another build on the site!
ReplyDelete