Madcow "Level-2" Build, 4" Fiberglass Airframe w/54mm Motor

[kevinkal]

Thanks for the info. Kevin. It sounds like your new tracking nosecone is complete. I look forward to seeing the photos.
I may need to slow progress on this project for a bit. I have lots of items to knock out in prep for a camping trip. It's too easy to get wrapped up on the rocket!
K

 

[kcobbva]

kevin,

So with the hole drilled and the toggles clipped. Here's a shot of the external side. Note I tried to cut one toggle with a dremel and totally screwed it up. Stick with a pair of wire cutters instead if you go down that path. I used a Radio Shack SPDT MICROMINI Switch #: 2750625. Again I clipped them so nothing could come in contact and turn it off during flight. They're pretty tough turning on/off so I feel confident they won't get flipped.

 

[kevinkal]

Thank you for posting pictures with details. Those look solid.

 

[kevinkal]

It's been over a month since I last posted an update. Over the last few weeks I've been thinking about how to mount my Eggfinder in the nosecone. My design constraints were:

1. Work around the single forged eyebolt that I installed in my nosecone bulkhead plate. (A single centered 1/4" nut and washer protrude from the bulkhead plate just inside the nosecone.)
2. Employ one of the 5 screw switches sitting on my hobby desk that needed to be used.
3. Use the stock brass wire antenna with the Eggfinder Tx.
4. Handle no less than 100 G's acceleration shock load during an aggressive main chute deployment.
5. Must be removeable.
6. Must not interfere with the vent hole between the nosecone and payload volumes.
7. Must be reasonably lightweight.

I fabricated this over the last weekend and am generally happy with the result.
Please let me know if you see any design/fabrication concerns that I should address.

Here are some photos:

I used 1/4" plywood for the base layers.
I cut three 2-inch circles, then modified 2 to clear the eyebolt nut.
I cut the last one in half to be mounted on the sides of the tracker mounting plate.


Here's the base is bonded together using 15 min epoxy, and I've come up with a method to mount the screw switch where I'll be able to access it through a hole in the base of the nosecone base plate.



Another shot to show the clearance hole in the center of the plywood base stack next to the 1/4" Stainless eyebolt.



The moment of truth was after I'd bonded the main structure together.. and felt how solidly the mounting plate was held by the base. It's solid.


Mostly done, just need to wire in the screw switch


The screw switch is wired inline on the positive from the battery.


The battery is a Glacier 2S 450mAh 25C pack.


I drilled an tapped the plywood for 3mm 50 tpi nylon screws.
I mounted both the screw switch and the EggFinder with 3mm nylon screws.


Top Down. I chose to center the antenna, and slightly offset the EggFinder to achieve this.

 

[SCrocketfan]

Very cool setup!

 

[thomas]

Looks very nice.

 

[kevinkal]

Thanks Benno.

I think I've room for an Arduino and large metal gear servo in there too! =]

I hope to launch this setup on Saturday at TCC. I'm not sure how many motors I'll be able to put through it in one day, but should have the following to choose from:

AT 38/720
I327DM
I600R

AT 54/1280
J415W (probably going to be my favorite)
J540R
J800T

 

[kevinkal]

Looks very nice.

Thanks!

 

[SCrocketfan]

Thanks Benno.

I think I've room for an Arduino and large metal gear servo in there too! =]

I hope to launch this setup on Saturday at TCC. I'm not sure how many motors I'll be able to put through it in one day, but should have the following to choose from:

AT 38/720
I327DM
I600R

AT 54/1280
J415W (probably going to be my favorite)
J540R
J800T

Definitely needs a guided main chute!

I won't be at TCC this weekend but hope to see you in August, September, and/or October Skies. J415 is a great motor if you like the flame and smoke (pretty much a bigger J350), but I've found it underperformed a bit on my 3" ARLISS rocket (may not have been motor, may have been mass/CD estimations being off). Still very fun, and I'd be interested to see if you get the simulated altitude on that one. The J800 would be awesome too-I've flown the CTI equivalent (J760 White Thunder, you may have actually seen that as it was at the 4/2 Snow Ranch launch) and Blue Thunder really teleports!

One more note-if you preload the first flight's deployment charges (short the e-match leads and connect on site) you can definitely speed up prep a bit, but I don't usually plan on flying a redundant dual deploy rocket more than once per day even with pre-prepped charges. Certainly possible though! I just prefer flying lots of different rockets

 

[kevinkal]

I finally got some more flights in with this rocket. I was hoping to get a good test in for both my new Mobius Camera and my new Eggfinder TX / LCD setup. However, both flights went nearly straight up and landed close.. putting no strain on the Eggfinder system, which worked well if even for the short distance.
Flight Descriptions/Videos from Mobius Cam below:

Aerotech RMS 38/720 4 grain I327DM-14 Dark Matter (delay drilled to 10 seconds)
This is about the smallest motor I want to put in this 11.5 lb rocket. My OpenRocket sim showed that it would clear a 60" launch rod doing 48 ft/sec. It was also overstable at about 2.8 calibers. I made sure the winds were light before launching. It was a nice flight with the raspy sparking dark matter burst.. burning all four 38mm grains in less than 1.5 seconds. It reached 1472 ft.

[video=youtube;n7C3bFYmp3I]https://www.youtube.com/watch?v=n7C3bFYmp3I[/video]


Aerotech RMS 54/1280 3 grain J415W-L (14 second delay)
A full J Impulse motor, the J415W made for an impressive flight to 4613 ft, before the motor delay grain fired the motor ejection at ~11 seconds instead of 14 seconds. As the rocket was traveling less than ~75 ft/sec when this happened, it didn't do any damage or shave too much altitude off the flight. That white piece of debris that floats down next to the rocket right after the drogue deployment, is the extra masking tape circle I used to bolster the ejection charge cap. The flame out to the Multiple ported Nozzel was impressive, but it burned the paint at the base of my rocket around the engine retainer. I really like the White Lightning motors and the relatively long burn time.

[video=youtube;zJxMuFOmZ1s]https://www.youtube.com/watch?v=zJxMuFOmZ1s[/video]

 

[kevinkal]

I picked up a Mobius Camera Shroud from Additive Engineering.
I decided to install it using 3mm nylon screws. I used a tap drill carefully perpendicular to the booster and drilled then tapped all the holes perpendicular to the 4" tube. While the camera shroud appears to be 3D printed with screw shoulders flat across, I felt that the nylon screws would conform a little when tightened, and have a nice symmetrical straight in thread to the tube. This made them easy to cut flush inside the tube after installation using a hobby knife.
In the second video in the previous post, the camera survived the dynamic pressure of Mach 0.5 during the flight on the J415W. I hope it can handle passing through the transonic region.

Here's some photos:

I simply used a level to positon the shroud 6 inches below the top of the sustainer tube.


Drill and Tap


Nylon screws in, careful torque and it's solid.


Looks reasonably level to the fins

 

[kevinkal]

While I love the long accelerating and high flight, roar, smoke a bright white light of the White Lightning reloads, the J415W was pretty hard on my paint around the engine retainer. All the paint was destroyed in that area. I have some 500F Duplicolor Ceramic Engine Enamel that I will likely repaint this area with.
Here's some before and after shots, note the Multiple Port Rocket Nozzel used with the J415W reload:

Before, near perfect condition after multiple flights using single nozzle reloads:



After 1 flight on a J415W with the multiple port nozzel. Paint is destroyed.

 

[SCrocketfan]

Really nice flights! The video is fantastic. Sorry to hear about the early deploy on the J415 but that's one of the great advantages of FG-pretty much zipperless at low speeds

With dual electronics, have you considered flying without the BP charge (leave the delay in and tape over the empty charge well)?

Interesting about the damage-I would have expected the I327 to do a lot more paint damage-my Frenzy (cardboard+ply not FG) had similar paint damage after flying a J360, but that's a Skidmark and they tend to be the most violent of the sparkies.

Niether of my J415 ARLISS flights had that kind of damage, but there are some (very) minor burns to the unpainted back thrust plate on the rocket after flying two J415s. Here's a photo of the rocket thrust plate/retainer-this is before the first J415 flight, but it already had one flight on a CTI J244. I think the recessed nozzle on the AT loads may have something to do with the burns, and the thrust plate on the ARLISS rocket makes it less susceptible to damage. Also including a photo by Watermelonman of the J415-it's a very pretty motor!

 

[Nick@JET]

Looks like the I327 tried to take along a dare devil passenger ! Guess he couldn't hold on.

Both apogee deployments were early
Dual redundant - I've still used motor backup but still then 2-3 seconds long. I'm sure as I gain more experience I will remove the BP and plug when running 2 Alts.

Videos look great though

 

[kcobbva]

Looks you had a good time launching anyway. Paint can always be replaced. Great videos and excellent use of Dashware as well! I lost my camera this weekend as it was attached to my GI Joe that gets launched out of a scratch build I built 13 years ago. It came loose when Joe was ejected. Oh well. Just an 808. The second launch was that rockets swansong because this D***A** forgot to turn on the chute release which I used to ensure the two didn't tangle up. oops. That field is way too small to launch my Level2 though, so I'm living through your videos until the fall!

 

[NateLowrie]

I finally got some more flights in with this rocket. I was hoping to get a good test in for both my new Mobius Camera and my new Eggfinder TX / LCD setup. However, both flights went nearly straight up and landed close.. putting no strain on the Eggfinder system, which worked well if even for the short distance.
Flight Descriptions/Videos from Mobius Cam below:

Aerotech RMS 38/720 4 grain I327DM-14 Dark Matter (delay drilled to 10 seconds)
This is about the smallest motor I want to put in this 11.5 lb rocket. My OpenRocket sim showed that it would clear a 60" launch rod doing 48 ft/sec. It was also overstable at about 2.8 calibers. I made sure the winds were light before launching. It was a nice flight with the raspy sparking dark matter burst.. burning all four 38mm grains in less than 1.5 seconds. It reached 1472 ft.

[video=youtube;n7C3bFYmp3I]https://www.youtube.com/watch?v=n7C3bFYmp3I[/video]


Aerotech RMS 54/1280 3 grain J415W-L (14 second delay)
A full J Impulse motor, the J415W made for an impressive flight to 4613 ft, before the motor delay grain fired the motor ejection at ~11 seconds instead of 14 seconds. As the rocket was traveling less than ~75 ft/sec when this happened, it didn't do any damage or shave too much altitude off the flight. That white piece of debris that floats down next to the rocket right after the drogue deployment, is the extra masking tape circle I used to bolster the ejection charge cap. The flame out to the Multiple ported Nozzel was impressive, but it burned the paint at the base of my rocket around the engine retainer. I really like the White Lightning motors and the relatively long burn time.

[video=youtube;zJxMuFOmZ1s]https://www.youtube.com/watch?v=zJxMuFOmZ1s[/video]

Does the Mobius automatically do the gauge overlay on the video or did you do that post-production? If you did that, do you mind sharing how?

 

[thomas]

Looks pettry much like it is made with dashware, which is now freeware:
https://www.dashware.net

 

[kevinkal]

Really nice flights! The video is fantastic. Sorry to hear about the early deploy on the J415 but that's one of the great advantages of FG-pretty much zipperless at low speeds

With dual electronics, have you considered flying without the BP charge (leave the delay in and tape over the empty charge well)?

Interesting about the damage-I would have expected the I327 to do a lot more paint damage-my Frenzy (cardboard+ply not FG) had similar paint damage after flying a J360, but that's a Skidmark and they tend to be the most violent of the sparkies.

Niether of my J415 ARLISS flights had that kind of damage, but there are some (very) minor burns to the unpainted back thrust plate on the rocket after flying two J415s. Here's a photo of the rocket thrust plate/retainer-this is before the first J415 flight, but it already had one flight on a CTI J244. I think the recessed nozzle on the AT loads may have something to do with the burns, and the thrust plate on the ARLISS rocket makes it less susceptible to damage. Also including a photo by Watermelonman of the J415-it's a very pretty motor!
View attachment 297314View attachment 297315

Thanks Benno.
I'm guessing that there's some flow recirculation going on between my 4" diameter body and the motor exhaust. I think smaller diameter rockets would be less vulnerable to this problem. I do want to fly more J415W's.. so I hope to find the right paint that can take the beating and wipe clean.

 

[kevinkal]

Looks like the I327 tried to take along a dare devil passenger ! Guess he couldn't hold on.

Both apogee deployments were early
Dual redundant - I've still used motor backup but still then 2-3 seconds long. I'm sure as I gain more experience I will remove the BP and plug when running 2 Alts.

Videos look great though

Thanks Nick.

I think both Motor ejections occurred before they were supposed to. For the I327DM flight, I think my main altimeter was the first to fire right at apogee, however I think the motor eject fired next as heard by the ring of the hollow fiberglass tube when it fired... then the eggTimer delayed apogee fired 1 second after it's version of apogee.. well away from the airframe and camera.. thus we never hear/see it in the video.

Both launch ignitions seemed to take a moment after the button was pressed... I'm thinking the igniter lit the delay grains a second or two before the main motor lit... and thus the delays were shorter than intended. Again, all deployment charges were at safe speeds.. but I noticed there was an unexpected anomaly that I hope to eliminate in the future.

Aside, when I stitched the data together with the video, I had the timing syncronized pretty good.. however when Dashware generated the final video, I noticed that the audio was not lining up with the video and data any longer.. it seemed to be about 1 second off. Oh well.. too much work to chase that down right now.

 

[kevinkal]

Does the Mobius automatically do the gauge overlay on the video or did you do that post-production? If you did that, do you mind sharing how?

Looks pettry much like it is made with dashware, which is now freeware:
https://www.dashware.net

Nate, Thomas has it right.. I used Dashware to embed the altimeter and vertical speed gauges and altitude vs. time plot.

 

[kevinkal]

Looks you had a good time launching anyway. Paint can always be replaced. Great videos and excellent use of Dashware as well! I lost my camera this weekend as it was attached to my GI Joe that gets launched out of a scratch build I built 13 years ago. It came loose when Joe was ejected. Oh well. Just an 808. The second launch was that rockets swansong because this D***A** forgot to turn on the chute release which I used to ensure the two didn't tangle up. oops. That field is way too small to launch my Level2 though, so I'm living through your videos until the fall!

Sorry about your 808. It served you well with excellent videos! I was bummed that my Level2 turned 270 degrees in 1472 ft... was hoping for something like your video showed.
I'm on my 3rd 808 cam.. since I can't see to avoid all the trees when I fly my quad racer fast and low. I decided to not fly another Mobius on the quad since they're a bit too pricey to expose to certain doom like that on my quad racers.

I look forward to some fall flights.. perhaps a low impulse L, but most likely some full K's for me. Who knows, maybe I'll break 10k on the K if the full J put me near 5k. I recall you were hoping for 11k on the low L. Seems possible.. I would not have said that until looking at the data from the J415W flight.

 

[NateLowrie]

Looks pettry much like it is made with dashware, which is now freeware:
https://www.dashware.net

Thanks! It's something I need to put on my list to checkout.

 

[SCrocketfan]

Thanks Benno.
I'm guessing that there's some flow recirculation going on between my 4" diameter body and the motor exhaust. I think smaller diameter rockets would be less vulnerable to this problem. I do want to fly more J415W's.. so I hope to find the right paint that can take the beating and wipe clean.

That definitely makes sense. I also noticed you hit the simulated altitude on the J415 flight, very nice! I'm thinking the really rough finish on mine is what kept it below the sims, and taping a camera to the side didn't help. Time to sand and paint it and try again!

By the way, I have a CTI 2 grain and 4 grain with spacers I'd be happy to lend you if you want to give a mid K a try before going even higher-the 4 grain K740 is an awesome motor using the C-star propellent and really zips-1800Ns in a case that normally fits around 1600Ns! I'm actually planning to fly one in that canvas 3" rocket sometime soon, maybe even in August.

 

[kcobbva]

Thanks! It's something I need to put on my list to checkout.

Here's a link I used when I learned to use Dashware: https://www.rocketryforum.com/showt...eter-Data-to-Overlay-Dashware-Gauges-on-Video

 

[kcobbva]

I look forward to some fall flights.. perhaps a low impulse L, but most likely some full K's for me. Who knows, maybe I'll break 10k on the K if the full J put me near 5k. I recall you were hoping for 11k on the low L. Seems possible.. I would not have said that until looking at the data from the J415W flight.

Well I keep dreaming of doing this in Rocksim, so maybe at LDRS36.

 

[kevinkal]

I flew the Level2 on a J800T Saturday at the TCC Launch in Helm, CA. It was a hazy day, likely due to the wildfires burning around the state of California.

RockSim was showing that I would need a 14.2 second delay to apogee. From recent experience, this rocket coasts further than the simulation model. Thus, I decided to leave the motor charge out. I greased the end of the delay grain, installed wadding in the charge cup and put the circular cap on top of that. It worked perfectly, and the cap and wadding were untouched during the flight.

The altimeters were both in agreement, showing apogee at 4,759 ft. See the flight profile plot below.

I've been trying to make a nice on-board camera video, but Dashware is no longer working properly since Window 10 updated to build 1607. I've spent a lot of time trying to fix that.. but have failed. So, instead, here are some nice still photos taken by Benno. Thank you Benno!

Launch Sequence, I like the blue trailing flame from the Blue Thunder Propellant:


Here's the data from the StratoLoggerCF altimeter:

 

[kcobbva]

Very nice Kevin!!! I haven't tried dashware since I've updated the system. Heck I've not launched any of my larger stuff in a while due to sites not open. Great to see this bird still flying and now you have me on altitude!!! It's a race for the moon!

 

[kevinkal]

Thanks Kevin.
I'm eyeballing a larger case or single use motor in the high K range or low L. I need to edit my simulation model to get similar altitude results as my actual flights. I've been flying roughly 500 to 600 ft higher than the simulation predicts. I'm thinking that I might need to modify a global value of Cd. Perhaps 10,000 ft is possible on a Full K. I may have to wait until October to find out. I also have a J540R to fly in the Level2. However, it sims a few hundred feet lower than both the J415W and J800T.

 

[kevinkal]

With the J800T flight detailed above, I flew for the second time with my new Eggfinder Tx. It transmits to my Eggfinder LCD receiver, and then flight data is transferred in real-time to my Laptop via Bluetooth. The system worked very well on this flight. As expected, data was lost during the boost phase to apogee. Very near apogee, 4730 Ft, I again was receiving valid data. Only one outlier data point was received during the boost phase. The outlier data point showed low altitude about 1 mile west of the previous point. I edited the track file an simple deleted this single outlier data point. Here's a screen capture from Mapsphere, showing a 3D view of the flight:

 

[kevinkal]

[FONT=Arial, Helvetica, sans-serif]I tossed together ground video, in-flight video and a few stills taken at the August 20th TCC launch in Helm for my Madcow Level2 Rocket on a J800T.
I had to find a Windows 7 PC in order to use Dashware to integrate gauges into the in-flight video.

I love the separated violet/blue flame on this motor.
Here's a link:
[/FONT]
[video=youtube;wNS36r3-BoU]https://www.youtube.com/watch?v=wNS36r3-BoU[/video]