bombarc help?

The Rocketry Forum

Help Support The Rocketry Forum:

crowem87

Member
Joined
Sep 29, 2004
Messages
6
Reaction score
0
Hello- my name is matt crowe and i used to be into model rocketry a few years back. I am trying to get back into it now and i am in the process of TRYING to build the north coast rockets BOMARC. I have built this rocket once before and it failed miserably in flight so i decided to give it a try again. I am currently stumped! i have the main body tube and motor mount tube assembled and the next step is to put a guide on the tubes to tell me where to cut certain holes. The directions say to place the guide 17" from the AFT end of the tube. I am not sure what end this is, and when i figure this out does it mean the bottom of the guide is 17" or the top of the guide? If you could be any help to me or give me the e-mail of someone who can help i would greatly appreciate it! thanks
 

Missileman

Well-Known Member
Joined
Apr 21, 2011
Messages
786
Reaction score
0
Welcome to TRF and back to the hobby.
First off, and it may be too late, that motor tube in the NCR kits is undersize and you will have problems getting a motor to fit.
NCR has been out of business since 2000 and the motors they used to make are near impossible to find.
If you can I would suggest replacing that motor tube with a new one from LOC or PML then you can use Aerotech motors.
The aft end is the end the motor tube is at.
I would say the bottom of the guide should be at 17" unless otherwise stated. Read through all the instructions and the markings may become more clear to you.
 

crowem87

Member
Joined
Sep 29, 2004
Messages
6
Reaction score
0
hey thanks a lot....ya i realized the troubles with the motors in the first bombarc i think we ended up using pliars to get the motors out....lol!....its deff. to late to take the motor mount because i epoxed it a few years ago....but that really helps....i think i will go ahead with your advice on the measurements...one other question, i ahve another rocket i built some years back and it has a 4 motor cluster. I never launched it because i didn't know how to ignite the cluster correctly?--
 

crowem87

Member
Joined
Sep 29, 2004
Messages
6
Reaction score
0
i jsut checked with an aerotec G motor, and it will fit after some work....do u think this will effect the flgiht at all. My first bombarc crashed and the parachutes never came out
 

Missileman

Well-Known Member
Joined
Apr 21, 2011
Messages
786
Reaction score
0
If you can get the motor in and it is tight enough you should have no problems. You will probably want a short delay.
Pay special attention to the CP (center of pressure) and CG (center of gravity) measurements. They should be listed on the last page of the instructions. If needed you may have to add weight to the nosecone. Check CG with the motor, chute ect.. loaded.
To light a 4 motor cluster, alot of people use a clipwhip.
It is a single set of wires soldered to 4 sets of wires with, of course 8 clips.
Use at least a 12v power source.
 

crowem87

Member
Joined
Sep 29, 2004
Messages
6
Reaction score
0
so your saying i need to check the CG and CP after i finish assembling the whole kit? how exactly do i do this, i have fogotten all the old techniques! i think last time the guy at the shop told me to add all the clay that came with it to the nosecone...and it didn't go very high- haha- can i get a whipclip at any hobby store?
 

Missileman

Well-Known Member
Joined
Apr 21, 2011
Messages
786
Reaction score
0
You can get Clip whips here:
https://www.thrustaero.com/pages/clips.htm
CP location should be given in the instructions.
CG should be between 1 and 2 Calipers (body tube diameter) ahead (toward the nosecone) of the CP.
If the CP location is not listed in the instructions then we will have to figure it out.
To check the CG (fully loaded) balance the rocket on the edge of a ruler, dowel rod, ect.. The point at which the rocket balances is your Center of Gravity, CG.
You can get non hardening clay at any arts and crafts store like Michaels for example.
Myself, I use #8 lead shot mixed with epoxy and poured into the nosecone. 25lb. bag is about $10 and gives you enough ballast to last a lifetime.
What I do is tape a sandwhich baggie to the nosecone and add weight into the baggie until I get the balance where I want it.
 

crowem87

Member
Joined
Sep 29, 2004
Messages
6
Reaction score
0
well we will ahve to keep this going becuase i know this rocket wotn come easy to me--i will try and finish it asap so i can check these weights and pressures. On the first one we used putty like all over the thing to make it look like there weren't creases where the plastics met, was this a bad idea, i have a feeling it added much weight-
 

Missileman

Well-Known Member
Joined
Apr 21, 2011
Messages
786
Reaction score
0
I don't think the putty would have greatly increased the weight. I am leaning more toward it changing the CG making the rocket less stable. Hence the importance of checking the CP and CG relationship on the finished model.
Similarly if you use a bigger motor in the future the CG must be checked again as the heavier motor will move the CG aft.
CP will always stay the same unless you make a change in the rockets airframe, add more fins, longer body tube ect...
 

n3tjm

Papa Elf
Joined
Jan 21, 2009
Messages
7,618
Reaction score
517
Location
Penns Creek, PA
The RMS 29/40-120 will have no trouble fitting in the NCR Tube. :). It's the disposable motors that gives people the headachs.
 

jetra2

Well-Known Member
Joined
Jan 25, 2009
Messages
2,795
Reaction score
2
Before I replaced my NCR Phantom 4000's booster section and MMT with standard tubing, I used to spend an hour the night before the launch sanding the SU motor down. What a big, fat, hairy PITA that was! It worked though.

Got any pix of the Bomarc?

Jason
 

crowem87

Member
Joined
Sep 29, 2004
Messages
6
Reaction score
0
no pics of the bombarc yet, im still in the beggining stages of it. Ya if i remember right i had to sand the hell out of the aerotech engines to fit them in the NCR tube...oh well whatever works.....i really like teh NCR kits i wish i could find some around for cheap!
 

Missileman

Well-Known Member
Joined
Apr 21, 2011
Messages
786
Reaction score
0
I just lost a bid on a Bomarc on Ebay,
I stopped bidding at $125.
The box was not only opened but in poor shape.
 

Stymye

Well-Known Member
Joined
Jan 21, 2009
Messages
7,599
Reaction score
6
crowem ,also one of my favorite rockets, no offence but it's spelled
B-o-m-a-r-c.
 

airwolfe1

Well-Known Member
Joined
Mar 1, 2004
Messages
107
Reaction score
0
For anyone looking for a mid power BOMARC kit, you can find a 1/12 kit on eBay. A guy by the name of Vin Sauriol [email protected] builds up these kits and has been selling them on eBay. He used to have a web store called Empire rockets but couldn't keep up. It's just a little hobby for some extra income so he went to eBay. Also, Deepsky sells a 1/14 kit, but you'd pay for shipping from England. It'd be probably double the shipping you'd pay here in the states. You can e-mail them and they'll give you the shipping cost.
 

Missileman

Well-Known Member
Joined
Apr 21, 2011
Messages
786
Reaction score
0
Originally posted by airwolfe1
For anyone looking for a mid power BOMARC kit, you can find a 1/12 kit on eBay. A guy by the name of Vin Sauriol [email protected] builds up these kits and has been selling them on eBay. He used to have a web store called Empire rockets but couldn't keep up. It's just a little hobby for some extra income so he went to eBay. Also, Deepsky sells a 1/14 kit, but you'd pay for shipping from England. It'd be probably double the shipping you'd pay here in the states. You can e-mail them and they'll give you the shipping cost.
I have been wanting one of Vins Bomarcs, I haven't seen his kits listed lately, thought maybe he was out of business.
I have his Nike Ajax and am very happy with it.
 

fehskens

Well-Known Member
Joined
Sep 11, 2002
Messages
49
Reaction score
0
>crowem ,also one of my favorite rockets, no offence but it's spelled B-o-m-a-r-c.

No offense, but it's spelled o-f-f-e-n-s-e.

;^)

There's a very nice large 1/14 scale (BT-80) Bomarc available from Paul Clark's Spacecraft Models, of V-2 and X-15 fame. I got mine from DeepSky in the UK. I'm hoping that a US dealer will pick up this model.

https://www.modelrockets.co.uk/

Look for it under Scale Model Kits. Deepsky will ship to the US.

len.
 
Top