With the upscale Yankee project on hold waiting for primer and warmer weather, I feel like this is a good time to build something else. I've mentioned on here a few times that I have a friend that is into rockets but because of some physical limitations he prefers to fly them rather than build them so I help out from time to time with assembly. A few weeks back he was at the house looking at my rockets and saw my Mean Machine and asked if I could build one for him. We talked about a build and he said he wanted it built exactly the same way I build mine. Since I didn't share my Mean Machine build with you guys the first time around, I figured I'd drag you along with me kicking and screaming the whole way.
Over the years I've built, flown and like most of us, crashed my fair share of Mean Machines. As I see it, the rocket has two issues that need to be addressed. Both have to do with it's length and both are resolved with two modifications. Due to the length of the rocket, it's not at all uncommon for the recovery system to fail to deploy. There is simply too much empty body tube there for something like a D12-3 to pressurize consistently. I crashed my first MM twice this way after weak ejection charges.
The second issue is the strength of the tubing. If you have ever watched a stock mean machine fly you've undoubtedly seen it bend and flex during flight. If you give it a little too much thrust, it's not uncommon to see the rocket fold in half on launch. This is what happened to my last MM on an E20. About 100ft into the flight it simply folded itself in half.
Let get the build started. For the most part we are going to use the kit parts with a couple of exceptions. The stock heavy plastic coupler is not being used. I'll also be adding a length of coupler with a bulkhead, a couple of extra centering rings, 1/4" lugs, 8ft of shock cord and 40 inches of BT50H tubing for a stuffer tube (yes it's only 34" in the pic. I remembered basic math after taking the pic). The stuffer tube will reduce the internal volume for moor consistent ejections and the the extra tube and centering rings will add much needed rigidity to the entire rocket.
Getting started with motor mount. I've marked the motor tube at the 3.5" mark for 1/4" overhang of the motor. A motor block will be inserted at the 3.5" mark as well.
With the motor block inserted, I attached the motor clip. The first inch or so of the clip was glued in place to help keep it from moving using medium CA.
Next I applied the exterior ring to keep the motor clip in place. After testing the spring tension, I decided that I wanted the ring installed 1.25" from the rear of the motor tube. This was attached using TBII.
Next I installed the lower centering ring. For this I used one of the stock paper rings but did coat it in TBII for a little extra rigidity.
Going to let this dry. Hoping to have a little time to get the couplers and centering rings installed after dinner this evening.
Over the years I've built, flown and like most of us, crashed my fair share of Mean Machines. As I see it, the rocket has two issues that need to be addressed. Both have to do with it's length and both are resolved with two modifications. Due to the length of the rocket, it's not at all uncommon for the recovery system to fail to deploy. There is simply too much empty body tube there for something like a D12-3 to pressurize consistently. I crashed my first MM twice this way after weak ejection charges.
The second issue is the strength of the tubing. If you have ever watched a stock mean machine fly you've undoubtedly seen it bend and flex during flight. If you give it a little too much thrust, it's not uncommon to see the rocket fold in half on launch. This is what happened to my last MM on an E20. About 100ft into the flight it simply folded itself in half.
Let get the build started. For the most part we are going to use the kit parts with a couple of exceptions. The stock heavy plastic coupler is not being used. I'll also be adding a length of coupler with a bulkhead, a couple of extra centering rings, 1/4" lugs, 8ft of shock cord and 40 inches of BT50H tubing for a stuffer tube (yes it's only 34" in the pic. I remembered basic math after taking the pic). The stuffer tube will reduce the internal volume for moor consistent ejections and the the extra tube and centering rings will add much needed rigidity to the entire rocket.
Getting started with motor mount. I've marked the motor tube at the 3.5" mark for 1/4" overhang of the motor. A motor block will be inserted at the 3.5" mark as well.
With the motor block inserted, I attached the motor clip. The first inch or so of the clip was glued in place to help keep it from moving using medium CA.
Next I applied the exterior ring to keep the motor clip in place. After testing the spring tension, I decided that I wanted the ring installed 1.25" from the rear of the motor tube. This was attached using TBII.
Next I installed the lower centering ring. For this I used one of the stock paper rings but did coat it in TBII for a little extra rigidity.
Going to let this dry. Hoping to have a little time to get the couplers and centering rings installed after dinner this evening.
