Loc LaserLoc 163, Mach 1 on Level 1 motors (with modifications)

[o1d_dude]

That's a BIG streamer!



Or is it 5'? Is this a different streamer? I've heard that BAMA Chutes has nice stuff, that should be great for visibility. I have ZERO room for anything else besides shock cord, my deployment charges, and maybe a bit of dog barf. But I'm leaving room for a 4 grain case, so that is what makes it tight.



Yeah, I think that they're slightly different sizes. I think that my bulkhead with threaded nut will work, the only downside is that it is in a fixed position, so I can't move it around, or use motor ejection as a fall back. But that's alright, I'm building this rocket for one specific flight.

The streamer is made of 5’ strips sewed end to end for a total length of 25’.

I plan to roll it up and it should just fit into the BT60 tube.

As to the placement of your bulkhead, you’ve probably already figured this out, thread the screw into the closure and insert the motor into the body tube. Then measure the distance from the front of the tube to the bulkhead. That will give the exact location for mounting the bulkhead so you maximize you shockcord space.

Look at us...breaking Mach and one mile high with a paper rocket. We ain’t all there, are we? LOL!

 

[mbeels]

I used a 5" x 50" streamer from Dino Chutes with my Alien Interceptor (which weights nearly a pound more) as a drogue one flight, but it brought it down too slowly, so I switched to drogueless for the next flight.

Yes, the bulkhead is positioned for the 4 grain motor, which leaves just a few inches for shock cord.

Look at us...breaking Mach and one mile high with a paper rocket. We ain’t all there, are we? LOL!

That means we're having that much more fun!

 

[mbeels]

The vinyl from Mark at stickershock23.com arrived today, I get more excited about these stickers than most other rocket purchases. It's just such a nice finishing touch.

Although cosmetically I have veered far away from the LaserLoc, it is still pretty close to a LaserLoc in dimensions, weight, and purpose. But I'll call this one "Fandango", as in, "Will you do the ... ???"

 

[mbeels]

Oh man, I just noticed that I applied the lettering so that it reads "down", instead of "up". The other side is how I wanted it, reading up. I'll just only show that side. Heh.

ARGH. That's going to bug me.

 

[Nytrunner]

I orient lugs/buttons as "down" when lying horizontal and apply the lettering so its readable form wither side with lugs down. Imagine your lugs were on the left in your photo, and the lettering would be same direction.

 

[o1d_dude]

Never really gave the orientation of the lettering much conscious thought but a quick review of my lettered birds reveals that I have a strong bias toward making the lettering read from aft to nose cone.

No big. You can only see one side at a time anyway.

 

[mbeels]

I orient lugs/buttons as "down" when lying horizontal and apply the lettering so its readable form wither side with lugs down. Imagine your lugs were on the left in your photo, and the lettering would be same direction.

Ok. So you have one side with words up, and one side with words down. And the rod/rail underlines your lettering.

Never really gave the orientation of the lettering much conscious thought but a quick review of my lettered birds reveals that I have a strong bias toward making the lettering read from aft to nose cone.

I have the same bias.

No big. You can only see one side at a time anyway.

Yup!

 

[Nytrunner]

Ok. So you have one side with words up, and one side with words down. And the rod/rail underlines your lettering.

You got it

 

[mbeels]

Finishing up some details, the clear coat is on (Krylon), and the Eggfinder mini GPS tracker is built and installed in a sled in the nose cone. I used 4-40 screws countersunk in the shoulder to hold it in place.

All that is left is ground testing.

 

[o1d_dude]

Finishing up some details, the clear coat is on (Krylon), and the Eggfinder mini GPS tracker is built and installed in a sled in the nose cone. I used 4-40 screws countersunk in the shoulder to hold it in place.

All that is left is ground testing.

View attachment 420391
View attachment 420392
View attachment 420393
View attachment 420394

Nicely done on the sled.

Will definitely steal the nosecone sled design for my LaserLOC 1.6.

 

[mbeels]

I may dial it down from 0.7g to 0.5g. It was quite vigorous. But then again, I have no motor backup in this rocket, so it needs to come apart. Any suggestions? (skip to 0:57)

 

[mbeels]

Decided to do a second test on the drogue side with 0.5g. It still seems like plenty, shock cord was fully stretched out. I'll use 0.5g on the drogue side.

 

[mbeels]

Alright success! The "speed of cardboard" is at least mach 1.3. It flew yesterday at Red Glare.

(Baro) Altitude: 8398'
Time to apogee: 18.95 seconds

(Accel) Max Velocity: 1451 ft/sec
Time to max velocity: 1.00 seconds

Max acceleration: 54.3 G
Time to max acceleration: 0.55 seconds

Acceleration:



Barometric altitude, showing a nice mach dip:



Accelerometer velocity in ft/sec, and mach number:





I didn't attempt to record video, it was gone off the pad pretty fast, and I wanted to be able to watch it (as much as possible). The Eggfinder worked perfectly, I had to cross a wobbly bridge, past a dead fox, and ford a swampy drainage ditch, but it led me right to the nose cone, about 3,500' feet away from the pads.

 

[Mugs914]

Way to go Marten!!! Congratulations!

 

[Rocketjunkie]

If you are looking for flat out speed and want to use a L1 motor, try the Aerotech I600R. An extra 50 N-s, same burn time.

 

[mbeels]

If you are looking for flat out speed and want to use a L1 motor, try the Aerotech I600R. An extra 50 N-s, same burn time.

I looked at that motor, I don't have that case, and it wouldn't fit in this rocket, but I did pick up a SU I500 yesterday which is even 20 N-s more than the I600! I've got another plan.....

 

[mbeels]

Since I had an accelerometer onboard, I was interested to see if I could get a good estimate of the coefficient of drag (Cd). I first generated this plot of Acceleration vs velocity squared:



The slope of this line should be proportional to Cd, since:

$$ \Sigma F = ma$$

and there are two forces acting on the rocket, gravity plus the drag force (where u is the velocity):

$$ F_d = \frac{1}{2} \rho u^2 C_D A $$

The acceleration due to gravity is a constant 9.8 m/s^2, so the total acceleration on the rocket is:

$$ a = -9.8 - \frac{\rho u^2 C_D A}{2m} $$

that means the slope of the line (a / u^2) is equal to:

slope = $$\frac{\rho C_d A}{2m}$$

and solving for the coefficient of drag is:

$$ C_d = \frac{slope 2 m}{\rho A}$$

I calculated the cross section area of the rocket to be (in square meters):

$$A = 0.002005 $$

If I take just the linear section up to about 80,000 m^2/s^s, and fit a line, I get:



So I ought to be able to estimate the Cd by (using rocket mass of 27 oz at motor burnout):

$$C_d = \frac{0.000587 * 2 * 0.77}{1.225 * 0.002005} = 0.37$$

which seems low to me. Does this number seem reasonable? I may be underestimating the rocket mass at burnout.

 

[Zeta]

how are you guys doing motor retention on the LaserLOC 1.63"?

 

[Rocketjunkie]

how are you guys doing motor retention on the LaserLOC 1.63"?

Friction fit. Works well in a cardboard rocket like the Laser-LOCs. Reloads didn't exist when the kits were introduced. If flying a reload, put enough masking tape on it for a snug fit. Then wrap a couple layers of masking tape around the airframe/rear closure joint.
BTW, the best motor for the Laser-LOC 1.63 was the I132. (Next to a 54/1706 case)

 

[mbeels]

how are you guys doing motor retention on the LaserLOC 1.63"?

I put a bulkhead in with a 5/16" threaded nut. Then I have the option of using a MD retainer. But I've also done friction fit. It helps that I'm not using motor eject, and the solid bulkhead blocks the drogue deployment charge from trying to push the motor out.

 

[mrwalsh85]

Friction fit. Works well in a cardboard rocket like the Laser-LOCs. Reloads didn't exist when the kits were introduced. If flying a reload, put enough masking tape on it for a snug fit. Then wrap a couple layers of masking tape around the airframe/rear closure joint.
BTW, the best motor for the Laser-LOC 1.63 was the I132. (Next to a 54/1706 case)
View attachment 488960 View attachment 488961

Ooh, I've got a few I132s....

 

[mbeels]

BTW, the best motor for the Laser-LOC 1.63 was the I132. (Next to a 54/1706 case)

Ooh, I've got a few I132s....

I've heard that the CTI I 125 is a pretty great motor as well, that's on my short list of motors to try.