The two fins on the left are used in the bottom half. The tab on the root edge glues to the smaller diameter engine mount tube.
On the right are the upper section fins with no root edge tab.
All four fins have strake positioning lines burnt into one side of the fins.
Below are the reinforcement strakes, not part of the Centuri kit.
Why would you reinforce a fin that has a line cut halfway through it?
Check the old Centuri instructions at www.oldrocketplans.com HERE
The instructions mention an "Optional Strengthening Technique" in Step 6. This is simply gluing copy paper over the fin. I'll be explaining the technique coming up in a blog post.
The instructions on oldrocketplans say the fins were 1/16" thick. I don't remember them being that thin. These fins are 3/32" thick.
I'm fortunate to fly on grass fields. The paper laminated fins should be plenty strong landing on grass.
Besides, I don't like the looks of the strakes.
After the burnt edges are sanded off, stack the fins as best you can and round the outside corner. Sand this round with all fins at the same time for consistency.
Round only the leading edges on all the fins.
This was the first rocket I completed from my three box haul via the now legendary Estes Clearance Sale. I flew it for the first time yesterday, unfinished and unpainted. I used an A8-3 for a fairly low-level flight. Probably got as much distance from the ejection charge as from the engine. The nose cone half landed up near the street, narrowly missing the concrete. The motor mount half landed down the hill on the ballfield, 50 or so feet away. Based on the way the rest of my day went, I considered it a wildly successful flight. It didn't land in a tree.
ReplyDeleteThanks Wallyum,
ReplyDeleteI read your flight report on the forum. Any flight that doesn't land in a tree is a success.
You would think an A8-3 would be as big an engine as you'd want to use in this one.
Centuri only recommended the 1/26-2 and A8-3 engines.
The Estes reissue has the A8-3, B6-4 and C6-5 as engine choices!
With the nose weight it's kind of a pig. I'm eventually going to give it a B6-4 baptism when the weather breaks for real.
ReplyDelete