alaric
Oct 04, 2007, 03:46 PM
This is posted in the Laser Arts/MM P-51 thread, but wanted to put it here for the searchability factor...
The Alfa Micro Retracts are available from Hobby Lobby (http://www.hobby-lobby.com/retracts.htm) at slightly more than 2x the price of GWS blues. The question is are they worth it? I'll report back on that part in a century or whenever I get the plane built and maidened (whichever comes first).
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So I pulled out my Alfa and GWS retracts to do a quick comparison. Best I can tell the Alfas have smoother actuation (they also lock up and down like the GWS). They weigh practically the same. If you use all the stock parts for each then the Alfas weigh the same and you get a sprung-knuckle suspension.
That said they're obviously not a direct replacement (due to shape). Grrrrr.
Long description of Alfa vs GWS retracts:
Functionally identical, 9/16th travel, same thickness, Alfa's are narrower (15mm wide) and longer (36mm long). The pivot on the Alfa's is approx <1mm farther from the mount holes at the actuator end compared to the GWS, so you may only need to adjust the mount at one end. I'll tell you more when I get there.
Since the Alfa's come disassembled on trees it's easy to tell the plastic is fiber reinforced. I'm not about to dig into the GWS to figure their makeup, but it seems the plastic is more brittle.
Main unit is 3g for either. 4g for the GWS 6" long 1/16" dia. steel rod and 1g for the Alfa 4 13/16" long 1/8" dia. CF rod. Alfa has you CA the rod in place, GWS uses a set screw. GWS doesn't include a method of mounting the wheel, Alfa includes a simple plastic knuckle and the full kit has a 3g sprung-knuckle suspension thing as well. They also have a break-away design that my gram scale isn't capable of weighing. The pieces for both sides are less than 1 gram, very likely to be worth it.
The Alfa's have a 85 and 90 degree option. You can also have the retract action arc toward or away from the servo. But honestly pictures are far better at describing this stuff so I think I'll scan the docs and post them later.
The Alfa Micro Retracts are available from Hobby Lobby (http://www.hobby-lobby.com/retracts.htm) at slightly more than 2x the price of GWS blues. The question is are they worth it? I'll report back on that part in a century or whenever I get the plane built and maidened (whichever comes first).
---------
So I pulled out my Alfa and GWS retracts to do a quick comparison. Best I can tell the Alfas have smoother actuation (they also lock up and down like the GWS). They weigh practically the same. If you use all the stock parts for each then the Alfas weigh the same and you get a sprung-knuckle suspension.
That said they're obviously not a direct replacement (due to shape). Grrrrr.
Long description of Alfa vs GWS retracts:
Functionally identical, 9/16th travel, same thickness, Alfa's are narrower (15mm wide) and longer (36mm long). The pivot on the Alfa's is approx <1mm farther from the mount holes at the actuator end compared to the GWS, so you may only need to adjust the mount at one end. I'll tell you more when I get there.
Since the Alfa's come disassembled on trees it's easy to tell the plastic is fiber reinforced. I'm not about to dig into the GWS to figure their makeup, but it seems the plastic is more brittle.
Main unit is 3g for either. 4g for the GWS 6" long 1/16" dia. steel rod and 1g for the Alfa 4 13/16" long 1/8" dia. CF rod. Alfa has you CA the rod in place, GWS uses a set screw. GWS doesn't include a method of mounting the wheel, Alfa includes a simple plastic knuckle and the full kit has a 3g sprung-knuckle suspension thing as well. They also have a break-away design that my gram scale isn't capable of weighing. The pieces for both sides are less than 1 gram, very likely to be worth it.
The Alfa's have a 85 and 90 degree option. You can also have the retract action arc toward or away from the servo. But honestly pictures are far better at describing this stuff so I think I'll scan the docs and post them later.