Modification - Onyx to The Hornet

Contributed by Gary Sinclair

Manufacturer: Modification
(Contributed - by Gary Sinclair)

Rocket PicBrief:
Additional 6" payload section added, nose cone bulkhead added, 1/4" centering ring added to incorporate eyebolt hardware. Fiberglassed body, fins and fin-to-fin lay-up.

Modifications:
As a joint project between my son and my self this rocket started out with only a single body tube. Reinforcement of fins and body tube using fiberglass along with a fin-to-fin lay-up of 2oz fiberglass was the extent of the initial modifications. Apart from the replacement of the elastic with a 1/4" Kevlar® shock cord attached to the motor mount all other assembly was stock. However, a couple of flights later the plastic loop on the nosecone was stripped and we decided that a payload bay would be nice and would provide a solid point for the forward shock cord. Thus an additional 6" tube of LOC tubing 3"OD was used along with the appropriate LOC coupler assembly. We also took the opportunity to put in a bulkhead and all-thread assembly in the nosecone. The result was a rocket a bit longer that stock and without the requirement of any weight in the nosecone. Nosecone retention was an option in case we didn't want to fly with the payload bay (hence! , an eyebolt was added to the bulkhead in the nose cone).

I used my trusty food saver to vacuum bag the components being fiberglassed (lots of articles exist on how to do this). My Dremel and West Systems epoxy did the rest.

Construction:
The kit comes with:

  • 1 x 3" OD body tube (kraft paper)
  • 3 birch plywood fins
  • 2 centering rings
  • elastic shockcord
  • nylon parachute
  • (12") plastic ogive nose cone

Pros: As with all LOC kits instructions are brief and to the point (on a single card). But this was a simple kit and all parts arrived without damage and were complete. Materials for LOC kits are always first rate. I used my BSD fin template for alignment as the kid did not include one. It was easy to build but since this was a kit bash it took a bit of time to fiberglass all the materials. The fins were surface mounted so a fin-to-fin lay-up is absolutely essential if you want to fly it more than once without a repair. The resulting booster section was sturdy as a rock. More than a match for an H180. Finishing was decided by my son who wanted a 'bee or wasp' look. So we decided up on a black and yellow stripped body with alternating black and yellow fins (black on one side and yellow on the back). To top it off I had some Hornet decals made in various sizes. These were then placed all over the rocket at random to give a 'swarm' effect. We were well pleased with the results and were sure it would fly straight after allot of ROCKSIM simulations on various motors and wind conditions.

Cons: None, though I do think that LOC couplers are a bit too fuzzy and can peel over time. The shock cord had to go of course as I don't like elastic. But otherwise it was a great kit to build.

Rocket LaunchFlight:
Pros: The initial flights were without the payload bay (as mentioned earlier) and we started with a G54W-6 RMS reload. The boost was great but the ejection charge stripped the nose cone from the shock cord (it was held on by the plastic loop -- too weak and too much BP). The nose cone came in ballistic but was otherwise undamaged (as discussed above we later put an all-thread and bulkhead assembly into it to create a better 'hard point' for the shock cord). The rocket body was recovered via parachute and was undamaged.

Flight number 2 (pre-bulkhead and payload bay) was on a G104T-6 and suffered the same fate as the first (i.e. the nose cone plastic was stripped by the Kevlar® shock cord further damaging the end of the nosecone). Again the body was recovered via parachute and was undamaged.

The next launch was after we had modified the nose cone and introduced the payload bay and was going to be on an H128W-10. At the appointed time we pushed the button and whoosh up it went (fast) with a perfect deployment of the chute (nose cone in tact and attached).

The last and most recent launch was on an H180W-10 and wow did it leave the pad quickly. I wasn't afraid of a shred though since we had built it so strong. Unfortunately I did not put in enough BP and the nose cone did not separate at apogee. The rocket whistled down and buried itself in the farmers field with a 'thud'. Bad news...the payload bay was stuffed inside the booster and my Marshal transmitter broken (a rather expensive loss). However, the booster section was mostly intact so I can rebuild this in no time at all.

Cons: None really since this is such a simple rocket and at 3" OD you have lots of room to put in a parachute. Motor retention was not a problem since I built it with a AeroPack retainer.

Summary:
Pros: Simple and easy to fly (assuming you don't blow the nosecone off like I did).

Cons: The coupler tubing is going to wear and could limit the lifespan of this rocket.

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