(08/27/01) When I purchased my BSD Thor, I knew I would also need to purchase
new motor hardware. So I also purchased a 38mm set with a 38-240, 360 and 480
case. I also purchased a PML 54mm to 38mm adaptor to allow me to fly the
54mm-based Thor on my new hardware. So needless to say, this was a large
outflow of money to venture into the largest rocket I have built. Is it the
tallest I've built? No, the
was 87" compared to the Thor's 85". Was is the widest I've built? No,
x2 is 5.5" compared to the Thor's 4". But the combination of
height and width made this the biggest rocket that I have built and that was
exciting as I pulled the pieces from the box.
includes four (4) lengths totalling 68" of 4" glassine-coated paper
tubing and a plastic nose cone to make up its length. There are two (2) 6"
couplers to connect the tubes. The motor tube is a 54mm tube that is 17"
long. There are six (6) large, 3/16" thick plywood fins, three (3)
1/8" composite centering rings, and two (2) 1/8" composite bulkheads.
The recovery system includes a 4' x 1" nylon strap and 20' of 1" wide
elastic, a quick link, two (2) Eye-bolt assemblies, and a 45" diameter
nylon parachute. BSD has also started to provide motor retention hardware which
included a pair of blind nuts, allen head bolts and retaining clamps. There is
a 1/2" diameter launch lug provided and a wonderful set of vinyl and
brushed gold decals.
This is my second BSD kit (Diablo)
and the 10 pages of instructions are one of the highlights to a BSD kit. They
are illustrated and photo illustrated. They give more than just step-by-step as
they provide information on optional dual-deployment configuration, numerous
building tips, Level 2, marking CP, CG and vents, etc. So even though this is a
big rocket (all relative) the instructions could guide a moderately experienced
builder to a successful build.
I have found that as individuals build more and more
high-power rockets they make more and more modifications to the kits they
purchase. Not necessarily a negative against the kit, as they are really trying
to employ "favorite" techniques. The Thor can be built 100% stock
with no modifications and be a perfect Level 2 kit. So, did I build mine stock?
I made only two minor changes. I added a 2nd eye-screw to the upper bulkhead
and one to the nose cone so that I could put a strap from the bulkhead to the
nose cone. I also didn't install the launch lug and used Blacksky Rail Buttons
As far as the build goes, it was straightforward and
fairly easy. I found that I had to sand the inside and outside of the three
centering rings just enough to take the black from the laser cut off to fit the
tubes nicely. Other than that all the parts fit together well.
Follow the instructions
closely because you don't want to go slopping glue around until they tell you
to so that all the parts fit correctly. This is especially true for checking
the fins against the centering rings and verifying fit through the fin
Speaking of the fins and slots, this
was, in my opinion, the most challenging thing about the build. The body tube
is pre-marked and you must physically cut the fin slots yourself. It's not a
terribly difficult thing to do, but as BSD recommends ensure you have a sharp
knife. Also be aware to take your time. You will be cutting six (6) slots. The
biggest problem of installing the fins in aligning the upper and lower fins.
BSD provides a fin guide and then suggests using a scrap piece of wood that is
"tack glued" to the upper and lower fins to keep them in perfect
alignment. I used an angled ruler and clamps. Mine did not come out perfect but
not terrible. I think I had "slopped" some glue and one of the upper
fins didn't sit flat against the motor tube. It's not obvious unless you go
looking for it, so I moved on.
For fin fillets, I deviated from
the directions and used ProBond glue for initial fillet. This does a good job
filling any gaps between the fins and the body tube. I then followed that up
using 30-minute epoxy with then gives a nice smooth fin fillet. I've been using
this technique on most of my builds lately. It took a lot of glue to do these
comments about ProBond glue)
There is one area that
has come to bother me about the Thor kit. That is the bottom of the rocket and
the amount of exposed body tube without support. There is just about an inch as
seen in the picture. This didn't seem to be a problem until after flight. Every
landing bent that section in some way or another. The instructions talk about
this area and suggest "to coat the entire centering ring and inside of the
airframe tube at the rear of the rocket with epoxy. This will help protect it
from heat and impact." Maybe it "helped", but it was still a
problem for me. I would suggest (and have no idea how well this would work)
taking a piece of coupler and gluing it into the rear section below the final
centering ring. This would effectively double this area and increase its
Finishing was the most time consuming task because of the
rocket's size. Even though I used my standard method for finishing
Kraft paper tubes and also for finishing
plastic nose cones, it just took a while. I also had trouble finding a
stand to hold it while painting. For the bottom section I took two bar bell
weights, stacked them, and put a 1" in dowel in them. I then took a cap
from a can of primer and punched a hole in it and pushed it over the dowel. The
54mm motor tube was then held fairly sturdy with this arrangement. For the top,
I tied a rope to the eye-hook and suspended it upside down from the garage
ceiling. In this manner I was then able to paint both sections. BSD has a nice
color scheme on their prototype. I choose a different color scheme. I painted
the bottom with ColorWorks by Krylon Gold and the upper section with dark blue
paint from Walmart (additional
comments about Walmart paint). I then used used Krylon Clear over
everything to finish it off. Be sure to wait a week before putting Krylon clear
or anything over any other paint!
After painting I started on the decals. There are a lot
and this too takes a lot of time. I applied all the black decals, but didn't
use the yellow THOR or the Brushed Gold. I decided that it would look a lot
better with a gold THOR so I contacted BSD about purchasing a set in Gold. They
were able to accommodate this request. I will be cleaning it up after a
somewhat rough trip (on the finish) to/from NARAM-43 and then applying the gold
The last thing I did, which isn't part of the kit, was to
build up a PML 54 to 38mm adaptor and install Blacksky Rail Buttons.
Overall, for CONSTRUCTION I would rate
½ points. I really can't stress it enough, that for this size of
rocket the instructions would allow less experienced builders to be successful.
The parts quality is good. The kit comes with motor retention and a wonderful
set of decals. Right on! The other thing that should be said, is that the
instructions didn't ignore that some may want to modify the kit for
dual-deployment and then gives recommendations on how to do that. If we could
stop that rear tube damage this would be perfect!
As far as flight, again BSD give clear instructions on
preparation and suggest an H123W-S for its first flight. They also recommend
the I154J, I161W, I200W, I211W, J350W, J135W, and J415W. My flights were
thoroughly planned for NARAM-43. My flight plan was an H123W-S, then an
I161W-M, then an I211W-L, then an I357T-M. I was successful in getting all four
(4) flights during NARAM-43. Pictured here (a bit blurry) is the I211 flight.
My RockSim'd rocket shows this for the planned
My rocket had a CG at
54.75" from the nose cone. BSD indicated that CP is 64.75" from the
nose cone (20" from the bottom). BSD's web site says the Thor weighs
between 3 and 5 pounds ready to fly. My finished rocket weighed in at 89 ¼
ounces (5 ½ pounds) without the motor, so the weight of my PML adaptor and
the gluing really seemed to take the weight up. Two other weight adders were a
very large eye-bolt that I screwed into the nose cone and an small eye-screw in
the upper bulkhead. These were added to allow me to tie a strap between them,
just in case the nose cone popped off.
My first 38mm flight ever and the first flight of the
Thor was on an H123-S. Lift off was slow with relatively low altitude (RockSim
says 630 feet). The rocket had arched over and was nose cone down upon
ejection. Descent was a bit too fast and it suffered its first small dent upon
the bottom edge of the body tube.
The next day, I loaded an I161-M. My first "I"
motor. It was a bit windy but the Thor took off and gave a beautiful straight
flight. I could hear a whistling after thrust stopped that I presume to be from
the gap between the upper and lower fins. Again, the nose cone was down upon
During the same day, I prepped the Thor for its I211-L
flight. The long delay was a concern, but a medium seemed too short, so I was
stuck in the middle. Wow, those 211's are nice. Deployment was late as it was a
couple of seconds past apogee. While coming done under 'chute the upper section
came loose (I guess I didn't attach the strap to the bulkhead) and fell on its
own. Scratched the paint but no damage.
The last flight was the next day on an I357-M. Great
punch off the pad, the delay was long again by a couple of seconds, but it
Again all recoveries were fast enough to dent that bottom
section. The damage picture above is after the last flight on the I357. I think
I will be bumping up the size of my parachute and I will also be flying the
next flights with dual deployment.
For FLIGHT/RECOVERY, I would rate this kit
points. I'll blame the weight of my rocket on the fast descent rate and
not take away on the rating.
I'd recommend this kit as a good candidate to do double
certification on the same rocket. Go ahead and do your Level 1 on an H123, the
switch to a "J" for your Level 2. Overall, I enjoyed building and
flying this rocket. I211's will be what I push for (as I am not Level 2 yet)
when flying it in the future. The kit has great instructions and quality
components so you can't lose. I give the kit an OVERALL rating of
Agreed on the tail-damage issue - All new runs of the Thor will not have a "notch" in the aft fin set - therefore, the aft ring is now located nearly flush with the end of the airframe tube This should eliminate this kind of damage, with no loss of strength. All kits date-stamped from 10/25/01 on will incorporate these changes. We found the same with the original Horizon and Horizon 54, which were changed earlier this year. Thanks for your input! - Scott Binder (BSD High Power Rocketry)
(by Allan Trau - 07/01/02)
Single stage, dual deployment capable, three split-fin design.
The kit includes:
- 3 body tubes, 34" aft, 10" electronics payload, 24" forward
- 2 coupler tubes
- 3 plywood centering rings
- 3 aft 3/16" plywood fins
- 3 fore 3/16" plywood fins
- plastic nose cone
- 45" nylon chute
- 20' elastic shock cord
- Quick links
- rail buttons
- plastic rivets
- motor retention system
- vinyl graphic decals
Instructions a excellent, easy to read and follow. Pictures are included
with most steps. Diagrams of the rocket are provided for dual deployment. A fin
alignment template is included.
The materials are of high quality and fit with minimal sanding. The rocket
is solid when completed. Addition of finishing epoxy plus some sanding to the
couplers makes the payload sections a snug fit.
When applied properly, the vinyl decals look like paint. If you've never
applied this type of decal before, it's a piece of cake and the outcome will
surprise you. I can't get over how good they look.
½ out of 5
Have only flown it once so far, but the motor selection for the Thor includes a
wide range. I flew it on an Aerotech J420 Redline.
Wadding is suggested, but I replaced it with leather chute protectors. The
motor retention system provided are two blind nuts, screws, and clips. Simple
The rocket flew straight as an arrow, did not notice any spin.
Shock cord is a braided nylon strap and 20' of elastic shock cord. I added
another nylon strap for dual deployment. The chute provides a quick decent, not
fast or anything, but the sturdy design of the rocket can withstand the
landing. Upsize the chute for harder surfaces. I encountered no damage at all.
½ out of 5
A pleasure to build - really fun. The instructions are excellent, materials are
excellent, design is great. The screws with the motor retention system have a
shoulder, so they can't be tightened all the way, but easily replaced with some
from the hardware store. The plastic rivets ensure you do not separate at
locations on the rocket not intended.
½ out of 5
(Contributed - by Chuck Pierce - 04/01/03)
Saunders, of BSD High Power Rocketry, graciously donated a 4" Thor kit for
a raffle prize, for the Huntsville Area Rocketry Association's (HARA) Rocket
City Blastoff (RCBO), October 2002. I was the lucky winner of this kit, and as
such, would like to reward Mark's generosity by posting this review to .
I approached Mark during the Summer of 2002 to ask if he'd be willing to
donate a raffle prize for HARA's RCBO in October. Mark quickly agreed to send
us a Thor, and we had received the kit a month in advance of the event. We had
received many nice donations for the RCBO raffle from BSD, Cesarioni, Aerotech,
Topflight Recovery, and many others; so, the raffle was a rousing success!
Luckily, my number came up for the Thor, and I carted the kit back home to be
built. Unfortunately, I wasn't able to start work on the kit until February,
which is why this review is being submitted nearly 5 months after receiving the
opened the Thor box, all of the pieces had been included and where well
packaged, and typical the high-quality instructions were included. BSD has
always provided some of the best kit instructions of any kits on market. The
specs for the Thor are that it's 4" diameter by 7' long, has a 54mm motor
tube, and should GLOW at approximately 5 lbs. Since this was a raffle prize,
I'd hoped to build it stock, but I rarely build anything stock anymore, and
this was the case with the Thor. My target motor was the Hypertek 835cc motor
system. So, the two main modifications were (1) lengthening the fincan airframe
from 34" to 44" and (2) lengthening the 54mm motor tube from about
10" to 28". Both of these mods were needed to accommodate the
30-inch-long 835cc motor. I also decided to fiberglass the airframe and fins
with 6 oz fiberglass cloth and Mr. Fiberglass slow epoxy. I adapted the
altimeter bay to accommodate an RRC2 altimeter for a dual-deployment recovery
setup. Due to the lengthened components, fiberglassing of the airframe and
fins, and altimeter, the Thor had a final no-motor weight of 8.5 lbs, and with
a nitrous-filled HT 835cc tank, GLOW'd at 11 lbs. The RockSim simulation can be
seen just above. The simulations for the 835cc/J330 and 835cc/J317 seem to be
right on the money, but the 835cc/K240 is quite optimistic (when I checked the
.ENG file, the total impulse of K240 had integrated to be about 25% higher than
the advertised impulse of the motor. I need to fix the file).
On March 8, 2003, I loaded the
finished Thor and a couple other rockets onto the roof of my wife's Xterra and
headed to the Music City Missile Club's sod farm in Manchester, TN. The weather
was beautiful (~70F...eat your hearts out all you Yankees and Canucks reading
this... :-)) with a 5 - 10 knot breeze. After helping several HARA members
complete their L1 and/or L2 cert flights, I prepped the Thor with a 835cc/K240.
With the altimeter armed, the tank was loaded, a 5-count was given, and the
hybrid K motor roared to life. Ascent was a nice and slow, long-burning boost
on the K240, and the recovery (drogueless to a Bob-Fortune 66" main at
500') was flawless. Several of the Civil Air Patrol cadets, who'd come out for
the launch, enthusiastically made the half-mile trek to recover the Thor. Peak
altitude was 3178'.
The Thor is wonderful kit! I've received MANY appreciative comments on the
Thor, and know of 2 folks already planning purchase to a Thor kit for
themselves. I sincerely hope that I've done justice to the kit and that many
folks seeing my kit and/or reading this review will want one of their own! We
all know that the rocket vendors don't have much of a profit margin, but still
gladly support many of our raffles and other fund-raising events. It is to the
credit of these many fine vendors, like BSD, that hobby rocketry is such a
wonderful hobby! Thank you, Mark, for donating this kit for HARA and thanks to
all of the vendors who have donated kits/equipment to support our rocket clubs!