BDB
Absent Minded Professor
- Joined
- Aug 22, 2015
- Messages
- 2,556
- Reaction score
- 938
Can't wait to fly the most expensive E motor ever.
+1 for pics and a launch report. I've been interested in some of these really expensive E engines myself.
Can't wait to fly the most expensive E motor ever.
Looking at the Tripoli Records pages, it looks like a bunch of hybrid records are unclaimed.
Anyone up for a record attempt this year? Someone needs to things started...
The RATT K240 rocket that I'm in the early design stages in RockSim is simming out at about 11k ft. For me RockSim is usually a bit 'generous', so I will be pleased if I can exceed 10k when it's built.
I'd have to use a Raven altimeter though, how distasteful....
I'd hope you could get more than 11K out of the K250...
Edward
I think I can get in excess of 13K with a min-diam 54mm Contrail based on OR sims. That's before playing with chilled N20 et al. That would be in "thick air" midwest/east coast sites. You guys who fly in the mountains have an unfair advantage .
My gathering of stuff to make the mini hybrid motor go boom is almost complete. Here's the BOM so far:
Mini Hybrid lightweight motor hardware $94 (+$7.95 S&H) Micronitrorocketry.com
Propellant Mandrel: Precision Ground 3/8 Aluminum Rod 12 Length $15 Amazon
018 Silicone O-Ring 100 pack $8.16 Amazon
009 Buna-N O-Ring 100 pack $2.08 Amazon
3M Super 77 Multi-Purpose Spray Adhesive $5.82 Amazon
Scotch Postal Wrapping Paper 30x30 $5.49 Amazon
DuPont Krytox Grease 0.5oz Tube $14.99 Amazon
16g Whip Cream Chargers (15 ct) $34.49 Amazon
Please note that by shopping around you will likely get better prices on whip cream chargers and mandrels, I am simply someone who has made peace with his Amazon dependency and doesn't care anymore. The expensive as heck Krytox grease can also possibly be ignored by simply using a new o-ring each firing, but I've never used krytox so I figured why not check it out.
The guide recommends making burst discs out of soda bottle PET or ping pong balls using a specially sized punch that I don't have; I'm going to try to hand cut a couple and see if I can maintain a good nitrous seal that way, worst case is I vent a cartridge to atmosphere.
I will also make my first pre-heater grains by cutting up a mid power reload. I also bought some random crap to make igniters with but I will save that for later.
Im going with simple paper grains since its super easy to start with, there are also some research recipes in the guide so be careful where you post details of the file. This morning I rolled four 7-8" wide lengths of paper grains, which was pretty easy (if messy with spray glue) and should yield about 8 firings worth of fuel. Next time I will just use watered down wood glue (way cheaper and easier to control). Tomorrow I'll use a small mitre/hand saw to cut the grains to length and make sure they fit well.
It seems that the 2050 is kind of heavy, I have seen a few fly and the K-888 load the most impressive in that motor, the other's seem to "stuggle" a bit. I think Contrail's 75mm sweet spot is in the 3200cc versions. For what its worth....
My plan for hybrids at LDRS is to launch RATT H80,I90, I90, K240(2X dual launch), M900, Skyripper K, Contrail M1491, and an Aerotech 54mm hybrid.
need to get my AT Hybrid up and running. Got all the schematics, just need a disk and pellet.
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