BSD 3" Thor

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Well-Known Member
Jan 20, 2009
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Does anyone know where the CP is located on the 3" thor? It's not listed anywhere that I can find in the instructions.

The CP for the 4" is listed at 20" from the rear. As all of the other dimensions of the 3" kit are 75% of the larger one, should I presume that the CP for the smaller version is at 15" from the rear?

IF, all dimensions, length, all fin dimensions, and locations are 75% of the 4" then YES the Cp will follow suit.
The BSD Thor in any proportion is definitely one of the coolest kits available in our hobby ;) There can't be such as thing as too many Thors!
The 3" THOR is a neat rocket! Here's a pic of mine ripping off the pad on a J-350. This bird flies really nice!

Where did you figure your thor's CP at? I'm planning on launching on a Pro54 1 or 2 grain, so I don't want to mess up on the stability...

Did you glass your fins? I have done tip to tip glass on the booster section to make sure that the fins stay put going up as well as on landing.

Mine is the 38MM version. To be brutally honest, I didn't bother checking the CP. A couple of factors influnced that decision:

1. The rocket is a proven stable design

2. By the time recovery components are added (electronics, chutes, harnesses) there is plenty if weight ahead of the CP for stable flight.

I built mine mostly stock, with a few modifications. I did not glass the fins or do anything special to the fincan. I did change the chute to a 48", because I felt the stock chute was too small. Details of the build can be found on my webpage at:


I would suggest emailing Mark Saunders at BSD. I'm sure he can answer your question.
Thanks Joe. Was it your review on EMRR? I have e-mailled Mark at BSD, but he hasn't gotten back to me yet. I have another e-mail address for him, but I hesitate to use it because I believe it is his personal e-mail address.

I'll post launch pics if I get any good ones!
I liked the beat me to it by just a couple of weeks! I'll still probably post mine after flight testing this weekend.

I heard back from Mark at BSD and he said, "The CP on the 3” Thor is 50.66” (Barrowman) and 52.55” (RockSim) from the nose. The empty CG on our model is 43.7” from the nose."

So there you go...just go to the source. He also said that he was updating the instructions to include this info.

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