Brief:
This is a clone of the Estes Bt-55 parachute recovery Bomarc. Finished in the Canadian paint scheme.

Construction:
The needed parts consist of:

• (1)18mm engine mount assembly
• (1) engine hook
• (1) bt-55x18" body tube
• (2) bt-50x6.5" nacelle tubes
• (2) nacelle tube pylons cut from 1/4" square balsa stock
• (2) Balsa nacelle cones(bnc-50BA)
• (2) 1/8x3/8 launch lugs
• (1) pnc55AO nose cone(or balsa)
• (1) 18" parachute assembly
• (1) raceway shaped from 1/4x3/8x16" balsa stock
• (4) round toothpicks for antennae
• (1) body marking pattern sheet clay or BB's for nose weight

I downloaded the plans for the#657 Bomarc from Jim Z's site, http://www.dars.org/jimz/est0657.htm The download included the balsa patterns and the dimensions for the two nacelle pylons..(1/4x1-1/2x3) The download did not include dimensions for the raceway, but I could pretty much scale the shape from the instructions.

This build was simply a clone of the original Estes kit, so I didn't spend a lot of time researching details about the real Bomarc missile. I'll save that task for a more accurate example of one to be built in the near future. I ordered the Canadian decals from Jim Z

The download includes a paint scheme for the USAF Bomarc for those who would prefer to build that version instead. I did not stray from the instructions, other than adding a length of Kevlarline to the base of the shock cord. I anchored the shock cord assembly to the engine mount. I did not attach the antennae. I felt they would be broken too easily. I have not made the two nacelle cones yet, but I plan to use a lathe or drill press to make them when I have the time to. For now, the Bomarc flies without them

I got all my materials from the hobby shops and tubes from an internet source.

The only problem I encountered was after I glued on the raceway, the yellow glue caused the rudder to pull to one side when it dried. I repaired this by using a hairdryer with a wooden block and a small clamp. I left the clamp on for a couple of days.

Finishing:

I used fill and finish on the balsa. I then filled some of the nooks and crannies with a small amount of bondo spot putty.

I tried to be sparce with the fillers and glues to keep things light.

I used minimal primer and gave it a finish coat of Gloss white.

I applied the water slide decals, but I am waiting to apply a sealer coat untill after I install and paint the Nacelle cones.

Flight:

I took the model out for a swing test and ended up adding 4 BB's and some epoxy to the inside of the plastic nosecone. I ended up with a 3.8oz total weight without the motor.

I flew her on a Quest C6-3 off of a 1/8x3'" rod.

She was a little squirrely and the launch rod velocity was borderline slow.

The altitude was about 350' with a slow rotation during ascent.

Recovery:

Ejection was very close to apogee.

Overall a fun couple of test flights

The 18" parachute was more than ample for the soft field conditions.and she recovered both times without any damage.

My suggestion to anyone who wants to clone this kit is to keep it light. Be sure to swing test your model!

Don't fly it on anything less than a C6. The next time I build one of these I will install a 24mm motor mount.

The Bomarc is a borderline stable model no matter how you build it, so be sure to check your cp/cg relationship.

Summary:

The Bomarc was somewhat of a challenge to build and a little more challenging to get it to fly properly.

It's a good attention grabber with the young kids at the launch site (and with the big kids too).