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REV 2.4 - Wed Oct 20 00:03:09 2010

OOP
Estes Industries
Gyroc (K-24)
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SPECS: 10" x 5.5" -
ROCKSIM FILE: Right Click to Download
SpaceCAD FILE: MISSING - please submit here
REC'D MOTORS: 1/2A6-2, A8-3, B4-4, B4-6, B6-4, B8-5, C6-5

Rating
(Contributed - by Tom Eldredge)

Rocket PicBrief:
A helicopter recovery rocket. My wife's favorite, because the prep time after a recovery is about 2 minutes -- put the engine, igniter, and igniter plug in, and the rocket is ready for another go!

Components:

  • Body tube: BT-20D (7")
  • Nose cone: BNC-20B (balsa) (any blunt one will do)
  • Fins: 2 large, 2 hinged, 4 rudders
  • No motor mount, just an engine block
  • No shock cord, parachute, or streamer
  • Short length of elastic string
  • Short length (2") of hardwood (popsicle stick works well)
  • Launch lug 1"
  • Hinge material (unscented bounce sheets work well)
  • Other materials you will need (as usual): pencil or pen, hobby knife to cut the fins, a sewing needle, and some white glue (no plastic parts).

Construction:
Construction PRO's: This rocket is pretty simple to build. There are relatively few steps, due to the simple design. Typical Estes picture-heavy instructions make everything go together well. Most of the "gotcha's" were spelled out in the instructions (gluing the fins together where the hinge goes). The only hard part of this whole "kit" is getting the elastic into the fins without destroying them. A sewing needle is almost too big, but the elastic is too thick for most everything else.

Another PRO is the sturdiness. You would think that the rocket repeatedly landing on the nose would dent it, or rip the fins off. However, while it looks like it is screaming down, it is really floating -- an optical illusion because it is spinning, I guess. Finally, there are only two fins to glue onto the body tube, so it is much easier to align than 3 or 4. You could probably use a ruler or other straight-edge to help also, if needed. Gluing the rudders is pretty easy, they need to be opposite of each other, which you can tell by sighting down the fin.

Construction CON's: Nothing really. A very simple rocket to build.

Finishing:
As this is a JimZ plans, there are not any decals supplied. So, you are free to make up your own scheme. I painted it in a spiral by painting the undercoat white, then masking off with a length of 3/4" tape. I also painted the fins and rudders alternating colors, so it really blurs when it comes down. This makes the finishing much harder than it has to be. Not too many nooks and crannies, so is easy to spray paint.

Construction Rating: 5 out of 5

Rocket PicFlight:
Flights are great. Put an A engine in (a B engine is almost too much, a C is out of sight for a LONG time), add an igniter and its plug, and you are good to go. The engine holds the fins straight until it ejects, which lets the elastic pull the bottom part of the fins into the helicopter configuration. No wadding to forget. No parachute to fold or get tangled. No shock cord to burn through, or cause a zipper. Man, what a waste! How are you supposed to CATO this? ;-) Mine flies pretty straight, but has a spin to it while boosting. I can't tell if I didn't position the hardwood against the engine right, or got the fins cocked while gluing them on, or the wind pushes it. However, it just adds to the "helicopter" feel!

Recovery:
The only CON here is that the elastic and hinge material wear out after a while. Mine has had about ten flights, and one fin only pulls a little. However, it doesn't seem to affect the spin much. I'll bet I have to replace both elastic strings, and maybe the hinge material too. I don't know what you could do to make it better, though! Ten flights and still going strong, better than most of my rockets ... but that's another story.

Flight Rating: 4 ½ out of 5

Summary:
Simple to build, very simple to prep, very little to go wrong on this baby. A great rocket. An added bonus: All the old-timers get a real kick out of seeing this one, too.

Overall Rating: 5 out of 5

[Submit your Opinion]

GUEST's OPINION:
"" (x.x.)

[Enter Rocket Specific Tip]

SPECIFIC ROCKET TIP:
06/07 - "I would recommend resisting the urge to use CA on the knots, at least the thin stuff. When I tried it the CA wicked up the entire length of the elastic, making it very stiff. I did the other side with plain old white glue, and it works great. Patience Grasshopper." (S.T. )

SPECIFIC ROCKET TIP:
07/06 - "Use a smaller, less destructive sewing needle by threading the eye of the needle with a loop of thread, pass the elastic thread through the loop, then pull the loop of thread back out of the needle's eye drawing the elastic thread through as well. The smaller needle reduces the size of the hole in the balsa parts reducing the chance of damaging the parts." (D.L.S.M. )

SPECIFIC ROCKET TIP:
10/05 - "Another great alternative hinge material is Tyvek paper cut from Tyvek shipping envelopes. The stuff is cheap, glues down like paper with white or yellow glue, and tear resistant. I've been using Tyvek as elevon hinges for my boost gliders with very good results." (D.L.S.M. )

SPECIFIC ROCKET TIP:
10/03 - "For better hinges, use thin flex hinges sold for small RC aircraft. They last longer and will take more abuse. Use 1/16th inch sewing elastic for the elevons. You can use an awl to make your hole (carefully), then burn the end of the elastic and crimp it so that it does not fray when it's placed through the holes. thread through rudders first, then elevons. This will make tying easier. Put a dop of CA at each hole after tying." (J.R. )

[Enter Flight Log]
Date Name Motor Ejection/
Altitude
Wind Notes
05-15-2010 Bernard Cawley Est SU A8-3 Apogee - Perfect 0-5 mph winds Event: Missile Mayhem 2010
- Spiral up (as usual). Good deploy. Practically landed on my canopy (on edge of road). Minor dent in NC.
09-18-2010 Bernard Cawley Est SU B6-4 Didn't See 0-5 mph winds Event: Rolling Thunder 15
- Squirrelly boost (one flap doesn't seat quite right anymore). Good on-field recovery typical of a Gyroc.
01-20-2001 Tom Eldredge Est SU A8-3 Apogee - NC Up 0-5 mph winds - Great flight, as usual. Fell mostly straight down, even in wind gusts.
11-12-2005 Matt Gillard Est SU A8-3 None - CATO 10+ mph winds pt1 - Incorrectly balanced, wildly unstable flight, hit ground and then ejected motor - fins deployed nicely! no damage, need to add nose mass.
11-19-2005 Matt Gillard Est SU A8-3 Apogee - NC Up Calm pt1 - altered nose mass, straight lift with spiral during coast phase, clean separation, fast spin and a slow decent. perfect -will upscale this plan to a 24mm motor.
11-22-2005 Matt Gillard Est SU B6-4 Apogee - Perfect Calm pt1 - straight up with large rotation at top, good spin on the way down, 11 seconds in total
11-24-2005 Matt Gillard Est SU B6-4 Just Past (1-2sec) 5-10 mph winds - spiralled up badly, not a high altitude flight, clean ejection, came down really fast.
12-08-2005 Matt Gillard Est SU B6-4 Apogee - Perfect Calm pt1 - nice staight lift, core ejected at apogee, fast spin, landed near pad
12-08-2005 Matt Gillard Est SU C6-5 Didn't See Calm pt1 - wild spiral up, did not deploy fins, came down hard and fast - no damage
04-14-2006 Matt Gillard Est SU A8-3 Very Late 5-10 mph winds pt1 - squirreled up, ejectionabout 50 foot from ground, spun in hard - no damage.
09-16-2007 Bob Harrington Est SU A8-3 None - Tumble 0-5 mph winds Event: CMASS section launch
- Went higher than expected. Nice slow helicopter recovery.
06-09-2007 Geoffrey Kerbel Est SU A8-3 Apogee - NC Down Calm Event: Club launch at local park
- Nice straight up and down flight. This thing is a great small park flier!
07-21-2007 Geoffrey Kerbel Est SU A8-3 Just Past (1-2sec) 10+ mph winds Event: School opening launch
- Major wind blowing and it still flew good! Very squirrly on the way up and still drifted quite a bit downwind even with max rod angle. Just stayed in school yard.
07-21-2007 Geoffrey Kerbel Est SU B6-4 Just Past (1-2sec) 10+ mph winds Event: School opening launch
- Same flight as last but higher and more twists and turns on the way up. Actually came down a little closer to the pad than the last flight. Good flight!
07-22-2006 Dwayne Surdu-Miller Est SU A8-3 Didn't See 5-10 mph winds Event: SAROS 22-Jul-06
- High straight boost, but squiggled a bit near the end of coast phase. Helicoptered with a very rapid spin rate, moderate decent. Landed softly on nose, didn't even mar the paint. Great flight!
07-22-2006 Dwayne Surdu-Miller Est SU A8-3 Didn't See 5-10 mph winds Event: SAROS 22-Jul-06
- High straight boost, but squiggled a bit near the end of coast phase. Helicoptered with a very rapid spin rate, moderate decent. Landed softly on nose, didn't even mar the paint. Great flight!
06-15-2008 Dwayne Surdu-Miller Est SU A8-3 Apogee - Perfect 0-5 mph winds - Slowly spinning boost and coast, straight up. Spinning helicopter descent.
03-23-2003 T Yaeger Qst SU A6-4 Apogee - NC Down 0-5 mph winds - Corkscrew up and hellicopter down. Not as pretty as straight up but not bad.
   

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