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View Full Version : BMS Clone of FSI Viking


chanstevens
08-19-2008, 02:15 PM
OK YORF'ers, I know a number of you have scarfed up Bill's first clone of the month offering and/or know quite a bit about the FSI Viking I. In a sport building frenzy this weekend, I grabbed an armload of whatever happened to have been recently purchased/lingering at the top of my build queue (heap), and of the 8 kits I put together, 3 were the BMS clones. In looking over this one, I'm amazed that it's using a 24mm motor tube. From whaty little I know of the history, the original FSI probably used something like a 21mm ID tube, which is why their instructions show layers of tape for the motor to fit. The BMS version uses a heavy wall BT-50, which works out to about 25mm OD, 24mm ID.

The original FSI kit had recommended motors in the A/B/C range with medium (4-6) delays. I would think a 24mm motor choice would be C11-5 or D12-5, though would think using a D is a one-and-gone strategy, especially if using the 14" chute from the original kit specs.

I plan on mocking up a Rocksim model tonight and suspect an 18mm adapter is appropriate, but was wondering if anyone's built one of these recently, or one of their own 24mm clones, and if so, what motors did you fly with?

Rocketflyer
08-19-2008, 02:29 PM
OK YORF'ers, I know a number of you have scarfed up Bill's first clone of the month offering and/or know quite a bit about the FSI Viking I. In a sport building frenzy this weekend, I grabbed an armload of whatever happened to have been recently purchased/lingering at the top of my build queue (heap), and of the 8 kits I put together, 3 were the BMS clones. In looking over this one, I'm amazed that it's using a 24mm motor tube. From whaty little I know of the history, the original FSI probably used something like a 21mm ID tube, which is why their instructions show layers of tape for the motor to fit. The BMS version uses a heavy wall BT-50, which works out to about 25mm OD, 24mm ID.

The original FSI kit had recommended motors in the A/B/C range with medium (4-6) delays. I would think a 24mm motor choice would be C11-5 or D12-5, though would think using a D is a one-and-gone strategy, especially if using the 14" chute from the original kit specs.

I plan on mocking up a Rocksim model tonight and suspect an 18mm adapter is appropriate, but was wondering if anyone's built one of these recently, or one of their own 24mm clones, and if so, what motors did you fly with?

Chan, I used the D12-5. Worked well, good straight flight and way up there. Went to a 12" chrome mylar chute, with spill hole. I would suggest that you use a heavier and longer shock cord. Ask me how I know. :o

Jack

lessgravity
08-19-2008, 05:26 PM
I also flew mine on a D12-5s. All have been great flights. The first launch I used a C11-3 which was also a good flight.

jetlag
08-19-2008, 06:04 PM
Since I was flying mine in a 'smallish' soybean field (35 acres) lined with huge hardwood trees, I chose an A8-3 in an 18mm adapter I made. I would imagine if I had used a D-engine, I might not see it again! The flight went fairly high (200ft?) and was uneventful and straight. Very nice flight, actually! The adapter gives one lower altitude options. I could easily have used a B motor, but did not. If I was flying at the Super Sod field in Orangeburg, SC, I would try a D...as long as I had some binoculars!
Allen

chanstevens
08-19-2008, 10:31 PM
Well, Rocksim thinks it's unstable but takes it to 1400+ feet on a D12-5 anyway. I'll probably do a first flight on a C6 just to see how she behaves and in particular gauge what the drift will be with a 12" chute. For higher flights, I'm thinking streamer.

FWIW, Rocksim file attached...

jetlag
08-20-2008, 05:15 AM
Well, Rocksim thinks it's unstable but takes it to 1400+ feet on a D12-5 anyway. I'll probably do a first flight on a C6 just to see how she behaves and in particular gauge what the drift will be with a 12" chute. For higher flights, I'm thinking streamer.

FWIW, Rocksim file attached...

Chan,
I'd be afraid the bottoms of the fin tubes might crunch under a streamer. Would an 8 inch 'chute be better? Or a 12 incher with a spill hole? The rocket is just great. I missed these growing up. Like a lot of folks, we had mostly Estes and a few Centuri/MPC/MRC/Cox from which to choose.
I strengthened the tube 'corners' on the bottom with a little thin CA wicked in. Held up nicely under the included 'chute. Guess I should take a picture.....
Allen

lessgravity
08-20-2008, 08:17 AM
Well, Rocksim thinks it's unstable but takes it to 1400+ feet on a D12-5 anyway. I'll probably do a first flight on a C6 just to see how she behaves and in particular gauge what the drift will be with a 12" chute. For higher flights, I'm thinking streamer.

FWIW, Rocksim file attached...

I tried a streamer on a particularly windy launch day with a D12. It was a good sized streamer but it still came in too fast. It broke off one of the tube fins on landing. All of my parachute flights have been good.

tbzep
08-20-2008, 11:57 AM
I tried a streamer on a particularly windy launch day with a D12. It was a good sized streamer but it still came in too fast. It broke off one of the tube fins on landing. All of my parachute flights have been good.

What type of streamer was it? I can bring down fairly heavy and fragile rockets with old fashioned crepe paper party streamers. I never use the plastic streamer material that is often included in kits or sold as streamer material. I make the streamer as long as possible, often 6 ft or longer, according to the diameter of the rocket. There is a point of diminishing returns concerning length and/or doubling. I always look at the streamer attachment area before prepping, and occasionally replace the streamers as needed, especially if I've recovered it on a damp field and I'm flying it again. I don't fool with using the contest materials or spend time with an iron doing fancy folding, but if you wanted to, you could do these things and get an even softer landing.

Rocketcrab
08-20-2008, 01:19 PM
I wimped out and put an 18mm mount in mine. It's first flight was at NARAM-50 on a C6-5, and it flew high, straight and true. The only problem was a slight ding at the top of the body tube - I assume the nose cone, with that heavy screweye for the CG/CP mojo, snapped back at ejection.

lessgravity
08-20-2008, 01:24 PM
What type of streamer was it? I can bring down fairly heavy and fragile rockets with old fashioned crepe paper party streamers. I never use the plastic streamer material that is often included in kits or sold as streamer material. I make the streamer as long as possible, often 6 ft or longer, according to the diameter of the rocket. There is a point of diminishing returns concerning length and/or doubling. I always look at the streamer attachment area before prepping, and occasionally replace the streamers as needed, especially if I've recovered it on a damp field and I'm flying it again. I don't fool with using the contest materials or spend time with an iron doing fancy folding, but if you wanted to, you could do these things and get an even softer landing.

This was a mylar competition streamer that I use in my B streamer competition rockets. It's a highly effective pleated streamer but the rocket still had damaged. I was surprised. The ground though was quite hard where it hit.

barone
08-20-2008, 08:20 PM
Here's mine.......

My shock cord is two times the rocket length. I think I installed the motor block so I could fly it with an E motor if I'm so inclined........ :rolleyes:

tbzep
08-21-2008, 08:12 AM
This was a mylar competition streamer that I use in my B streamer competition rockets. It's a highly effective pleated streamer but the rocket still had damaged. I was surprised. The ground though was quite hard where it hit.

I guess I'm just so used to flying in pastures with thick grass coverage that I don't think about hard packed ground. If your streamer won't slow it down enough, a normal one sure won't do it.

Doug Sams
08-21-2008, 09:32 AM
I guess I'm just so used to flying in pastures with thick grass coverage that I don't think about hard packed ground. If your streamer won't slow it down enough, a normal one sure won't do it.Considering ground condtions is a skill that comes a little more slowly. I've learned to consider the grass height, but still forget to think about the soil conditions. Here in Texas, the ground gets as hard as a rock in the summer, and that can break fins that would otherwise be just fine in the spring.

I've also learned that, even with plenty of extra chute, you can break fins due to cross winds. I've had plenty of rockets hit with plenty low vertical velocity but crack fins due to the horizontal speed :(

(For you MSOE alums, that's low dy/dt and high dx/dt :D )

Of course, if there wasn't any risk, it wouldn't be interesting :)

Doug

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lessgravity
08-21-2008, 09:57 AM
Here's mine
http://rocketry.files.wordpress.com/2008/02/viking1.jpg

moonzero2
08-21-2008, 10:50 AM
Here's mine
That looks AWESOME!

Mikus
08-21-2008, 11:01 AM
Sweet birds! :D

Doug Sams
08-21-2008, 11:26 AM
Here's mine
http://rocketry.files.wordpress.com/2008/02/viking1.jpgExcellent workmanship. Did you paint the tubes before you glued them on?

Doug

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lessgravity
08-21-2008, 11:54 AM
Excellent workmanship. Did you paint the tubes before you glued them on?

Doug

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I applied a mask to the side of the tubes at the contact point of the rocket. The mask was quite small and about the area that would come into contact with the main tube. This allowed me to paint the tubes and still create a good contact point between tubes. The surface under the mask was also sanded to create a good contact surface. i then painted tubes before attaching. After attaching I created my glue fillets.

tbzep
08-21-2008, 11:57 AM
Considering ground condtions is a skill that comes a little more slowly. I've learned to consider the grass height, but still forget to think about the soil conditions.

That's me to a "T". I always have good ground cover, so I usually only think about grass thickness and height. I seldom fly away from home. When I do, I usually get a little damage and realize I've spoiled myself flying in my own pasture all these years.

stefanj
08-21-2008, 11:59 AM
It is really neat seeing Vikings painted with that retro paint job.