Level 2 Build - Madcow Level-2 via Apogee Components

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Thanks Steve. The sizing chart showed my error... I mistyped.. I should have typed a P. I seem to be equating P with Paper tubes.. but it's for Fiberglass as I understand it.
I'm not certain what type of fiberglass tubes these are. they appear to be filament wound. Is that the same as G10? I am familiar with G10 plates.. solid as heck. The fins are what I understand to be 0.132 G10 plate, no bevel. The bulkheads and centering rings are what I understand to be 0.100 G10.

Here's some detail on the darn 54mm motor tube:
It's 12 inches long, but has significant variation in wall thickness and OD depending on what section I measure. The ID is consistent.
Wall thickness:
One end has wall thicknesses variation between 0.0585" and 0.060" around the circumference, but the other end has wall thicknesses variation between 0.051" and 0.058" around the circumference.
OD:
One end is 2.274" OD, and the other end is 2.266" OD.
ID:
One end is 2.159" ID, and the other end matches well as 2.159" ID. There is little variation around the circumference for the ID.

Per the Aeropack chart you've linked, 54P = 2.278”. Thus I see why my retainer slides on so easily. I plan to mount the AeroPack retainer on the thicker side of my motor mount tube. I suspect the JB Weld will have no trouble filling the 0.004" gap. The forward centering ring will have a loose slip fit and need the Rocketpoxy (Glenmar G5000 High Strength Epoxy) to fill the gap. Apparently, rocketpoxy is good stuff. I just looked to see what the hardest "hitting" 54mm motor would be for Aerotech... It's the J1999. That's about 450 lbs of thrust. I hope those 2 centering rings are up for the task should I ever load one of those hard hitters.

You should be alright on the retainer w/JB Weld. And yes, unfortunately a bit of variation on the fiberglass tubing, but seems like you are dealing with it just fine.
 
My kit arrived and I've only washed the tubes at this point. The inside of the tubes still seems like there may be a thin smooth film of mold release or something else still there. I'll just be sure to sand and roughen any bonding locations with sandpaper.
The Aero Pack 54mm "P" retainer slides right on either side of my 54mm tube. I've noticed that all these fiberglass tubes don't seem to have strict tolerance control. I think I'm seeing up to 0.010" variation in diameters and wall thickness.
I'm going to read the RocketPoxy instructions and call it a night. tomorrow I'll start bonding items, starting with the forward CR to the motor tube. I watched your video a few more times too. =]

I picked up an Aeropack 54-38mm adapter, and a Rouse Tech 38/720 Motor, and a AeroTech I327DM and I600R. It looks like I'll have 3 reloads to choose from for my L2 cert flight: J350W, J420R or J500G. All of these should get her off the pad quickly. I'm a little worried about being overstable. I've made an OpenRocket model, and I'm over 2 calibers stable on even larger motors. What does your Rocksim model predict for stability margin on your J250 cert motor? (I can't run Rocksim unless I buy it.. my 30 days were up)

Oh, I need to resolve a main parachute issue. My kit had only a 36" main chute in it... not going to cut it for this size bird... working to resolve that now. So what made you toss the stock parachutes and go with others?

Kevin - Congratulations..It's in your hands!! As for the bond release and all; just get a bucket of soapy water go outside and wash all the parts real good and rinse and let dry. Then go ahead and sand everything in every area they'll connect. That way you won't be having to stop every hour to sand a new part. Do it all now; enjoy the build later. :) As for the parachute, I too felt the 36" wasn't enough. I purchased a Loc Angel Small. https://shop.locprecision.com/product.sc?productId=230&categoryId=29 It seemed to do the trick very well. I used an XS on my level 1 bird and was really impressed; so I picked up a Small for the L2 bird.

I weighed every little piece during the build and it came out nowhere near what the rocksim file showed initially. I ended up using Mass Override on the actual weight and CG. My data is as follows:
Dry
3.99 overstable
Mass 146oz
CG 40"
CP 56.0416"

With Cesaroni J250 loaded
2.96 overstable
Mass: 175.2774 mass
cg: 44.1482"
CP 56.0416
 
The motor retainer body should contact the aft centering ring, which should contact the fin tabs. The thrust is thus carried by the airframe and fins via the contact between the aft centering ring and the aft edges of the fin tabs and then via the fillets (inside and outside) on the fin tabs.


[emoji1010] Steve Shannon, USA [emoji1010]
 
One obsessive thing I do is wrap tape around a motor case so it's a snug, but not tight, fit in the MMT. I do the same for the aft closure so it's a snug fit in the retainer body. When I JBWeld the retainer body (which is the very final step in assembling my aft sections) I insert the assembled and taped case to ensure centering of the retainer relative to the MMT bore.


[emoji1010] Steve Shannon, USA [emoji1010]
 
One obsessive thing I do is wrap tape around a motor case so it's a snug, but not tight, fit in the MMT. I do the same for the aft closure so it's a snug fit in the retainer body. When I JBWeld the retainer body (which is the very final step in assembling my aft sections) I insert the assembled and taped case to ensure centering of the retainer relative to the MMT bore.
[emoji1010] Steve Shannon, USA [emoji1010]

Excellent idea. I was dry assembling the retainer, mmt, and 54-38 adapter... and noticed that the alignment will be nearly 100% dependent on the retainer alignment to the motor tube. There's a good amount of slop in there..that could make for a little thrustline offset if it's not glued square to the motor tube. Forcing it to center and then bonding is the way to go. Thank you.
 
Kevin - Congratulations..It's in your hands!! As for the bond release and all; just get a bucket of soapy water go outside and wash all the parts real good and rinse and let dry. Then go ahead and sand everything in every area they'll connect. That way you won't be having to stop every hour to sand a new part. Do it all now; enjoy the build later. :) As for the parachute, I too felt the 36" wasn't enough. I purchased a Loc Angel Small. https://shop.locprecision.com/product.sc?productId=230&categoryId=29 It seemed to do the trick very well. I used an XS on my level 1 bird and was really impressed; so I picked up a Small for the L2 bird.

I weighed every little piece during the build and it came out nowhere near what the rocksim file showed initially. I ended up using Mass Override on the actual weight and CG. My data is as follows:
Dry
3.99 overstable
Mass 146oz
CG 40"
CP 56.0416"

With Cesaroni J250 loaded
2.96 overstable
Mass: 175.2774 mass
cg: 44.1482"
CP 56.0416

Thanks Kevin. Wow, 11 lbs on a J250. I'll definitely need a bigger chute. I'll see what Apogee can do for me.. else I'll need to pick something up that's more suitable.
I'm not too familiar with being "that" stable. But it's my understanding that having large stability margins is great during high speed part of the flight, but leaves the rocket more vulnerable to winds at launch, ie come off the rod then angle into the wind a bit too easily. I don't know how to avoid having a margin under 2.0 with this kit... too much weight forward. I'll just be careful not to put less than a 250 N class motor in with calm winds.
Kevin K
 
Thanks Kevin. Wow, 11 lbs on a J250. I'll definitely need a bigger chute. I'll see what Apogee can do for me.. else I'll need to pick something up that's more suitable.
I'm not too familiar with being "that" stable. But it's my understanding that having large stability margins is great during high speed part of the flight, but leaves the rocket more vulnerable to winds at launch, ie come off the rod then angle into the wind a bit too easily. I don't know how to avoid having a margin under 2.0 with this kit... too much weight forward. I'll just be careful not to put less than a 250 N class motor in with calm winds.
Kevin K

You are correct. Too much overstable and it'll weathercock into the wind, so you need to sim for different days on different engines and see what works best and fly accordingly. My CG was definitely different dry than that posted in the Rocksim file. I'll be very interested in what you come up with. Maybe it's because I used RocketPoxy vs Fix-it epoxy for the fillets? Who knows. but I added internal filets as well and that wasn't on the instructions that I recall. Oh well. It flew "straight" :)
 
Excellent idea. I was dry assembling the retainer, mmt, and 54-38 adapter... and noticed that the alignment will be nearly 100% dependent on the retainer alignment to the motor tube. There's a good amount of slop in there..that could make for a little thrustline offset if it's not glued square to the motor tube. Forcing it to center and then bonding is the way to go. Thank you.

For the record I don't do it to center the thrust; I do it so that a motor with a larger thrust ring will still fit. I honestly hadn't considered the thrust.


[emoji1010] Steve Shannon, L3CC [emoji1010]
 
Ok so now that I have the Level 2 Cert; it's time to learn a little more. I've decided to add GPS and a Beacon to the nosecone allowing me to fly higher with a better chance of recovery. After a great conversation with Teddy from OneBadHawk I decided on an Eggfinder, BigRedBee Beacon, a Yaesu FT-60R, and eventually a yagi antenna. Oh yeah...a special thanks to Cris for the Extra Quark!! An unexpected bonus!
Great Mail.jpg

After getting back from taking my Cubscout pack camping this weekend, I finally laid everything out. A new 5:1 Ogive nosecone from Madcow will be the "bay" for these electronics:
nose.jpg

the only issue I've had with this nosecone is the seams are flattened somewhat and the cone is not completely circular. Thus the fit the nosecone will need to be built up slightly:
nose issue.jpg

So the only time I use Fix-it Epoxy any more is to build a ring inside a nosecone to seat the inside edge of a centering ring. Here's the initial ring set, using an Attebery Performance Engineering Head-end Altimeter bay.
ring.jpg
I absolutely butchered my Eggtimer Wifi last Christmas, so I tried real hard to do the Eggfinder GPS tonight. Overall, I'm pleased. I am anything BUT a pro..have to wear 3.0 glasses to see this fine detail, and get neck cramps doing the work..but hopefully it all pays off this time! Stopping for the night after the GPS installation.
eggfinder gps.jpg
 
Kevin,
Looks excellent.. I'm going to copy your installation, but thanks to your tip I'll be able to use my stock nosecone when I do. You're also inspiring me to get out the soldering iron and solder up the Eggtimer Quantum waiting for attention. I'm very interested in how your Eggfinder GPS/Tracker works.
 
you will definitely want a yagi antenna. I use a three element arrow yagi antenna.
Also I don't use attenuators when I am fox hunting.

I will go off set the channel 2.5 kHz till the signal is too strong then I will go an other 2.5 kHz. most of the time I go up.
When I am off set, I listen to the audio. If the beeps sound right, it's in that direction.

~Russ
 
you will definitely want a yagi antenna. I use a three element arrow yagi antenna.
Also I don't use attenuators when I am fox hunting.

I will go off set the channel 2.5 kHz till the signal is too strong then I will go an other 2.5 kHz. most of the time I go up.
When I am off set, I listen to the audio. If the beeps sound right, it's in that direction.

~Russ

Thanks Russ. This is all new to me; so I look forward to eventually finishing and trying this out! Appreciate the tip greatly!
 
Kevin, ,
When your "fox hunting" for a direction from an RF signal
I'm not sure that you realize that a yagi isn't an option....
The yagi is an extremely directional antenna...
When you point it in the wrong direction your signal strength meter
will show you a weak signal,, if a signal at all...
When you point it in the correct direction ( the source of the signal )
the signal will look on the signal strength meter and sound much stronger. ...
This is how you get direction from it....
The rubber duck antenna receives equally well from all directions, ,,
so there's no way to tell which way the signal is coming from. ...

I'm sorry if you already knew this,, I wasn't sure.....

Jus checkin,, lol...

Teddy
 
Kevin, ,
When your "fox hunting" for a direction from an RF signal
I'm not sure that you realize that a yagi isn't an option....
The yagi is an extremely directional antenna...
When you point it in the wrong direction your signal strength meter
will show you a weak signal,, if a signal at all...
When you point it in the correct direction ( the source of the signal )
the signal will look on the signal strength meter and sound much stronger. ...
This is how you get direction from it....
The rubber duck antenna receives equally well from all directions, ,,
so there's no way to tell which way the signal is coming from. ...

I'm sorry if you already knew this,, I wasn't sure.....

Jus checkin,, lol...

Teddy


Teddy - EVERY little bit helps! Thank you. not only for ths, but for pointing me down the entire path! I wouldn't have gotten this far without all of your help! I greatly appreciate everything!
 
Teddy - EVERY little bit helps! Thank you. not only for ths, but for pointing me down the entire path! I wouldn't have gotten this far without all of your help! I greatly appreciate everything!

You are so welcome Kevin,,
You are truly a pleasure...

Teddy
 
Looks like I'll be delayed from attempting the high flight at the end of June in the NY launch. Family matters have overtaken my play time then. Alas, I can fly lower locally; and get used to the devices - then go for gold next time the opportunity presents itself! Hoping I can get back to the EggFinder tonight as I've finished a training class today.
 
Looks like I'll be delayed from attempting the high flight at the end of June in the NY launch. Family matters have overtaken my play time then. Alas, I can fly lower locally; and get used to the devices - then go for gold next time the opportunity presents itself! Hoping I can get back to the EggFinder tonight as I've finished a training class today.

You can't ask for a better scenario then that Kevin...
Sounds to me like when you REALLY need the tracking you'll be an old hand at it....

Teddy
 
Thanks Teddy. As I tell my young engineers...slow down and taste the coffee. Guess I need a dose of my own medicine some times! :)

So I got further along with the Eggfinder this evening, and then stopped at the antenna assembly as I think I'm going to go with the alt recommended antenna: Linx Technologies ANT-916-CW-QW and the RP-SMA JACK 50 OHM EDGE MNT connector. I'll order those in May and then get back to final assembly. Some things are definitely not done by a PRO; but I do believe it should work; unlike the previous WIFI.
eggfinder.jpg
 
Looking good Kevin. That looks like a 3d printed PCB holder. Nice. With all the 3D printed items in your build and toolkit, I wonder if you have a 3d printer?
I was taping an eggtimer to my table last night.. not the best way to solder.
 
Actually the tape on the table works much better. I only use this for quick jobs that dont move much., otherwise it prone to spin. And no..no 3D printer.
 
Ok so an UP and big Down today working on this project.

1st the UP: Cris at EggtimerTimerRocketry is AWESOME! I lost a 10k resistor somewhere and couldn't complete the LCD build. No questions asked, he simply shipped new ones to me! Let's see amazon match that!

Down: So for soldering I *(&@#$. I was so careful and while not professional really thought I did much better this time on both the Eggfinder and LCD module. (I dorked up a WIFI around Christmas) The eggfinder will not power up at all. Ugh. The LCD had a little puff of smoke beneath the LCD screen and that's all she wrote! Double Damn. I'm not done with Eggtimer equipment, it's awesome and Cris is a top notch dealer! I'm just done with ME doing these. Like driving down the road throwing $20's out the window. I'll pick up more and have them professionally done because I stink at it! Damn.
 
I'm sad to read of the "Down". Soldering those little surface mount parts is not easy. Even with a magnifier it's a challenge just to see what you're doing, let alone keep ones hands from shaking with the soldering iron. I hope you get it resolved with as little "pain" as possible.
 
I'm sad to read of the "Down". Soldering those little surface mount parts is not easy. Even with a magnifier it's a challenge just to see what you're doing, let alone keep ones hands from shaking with the soldering iron. I hope you get it resolved with as little "pain" as possible.

Yep...Called Outsource! That's 3 boards I've now dorked up. Would be better if my eyes were better I guess. I HATE not being able to do something; alas at some point the hands must go up. That point is today.
 
Kevin,
What size drogue did you go with and where did you position it in the "lineup"? Just below the payload? I could not tell from your video what your recovery looked like under the drogue.
I'm currently planning to use the stock 18" thin ripstop nylon drogue that came with the kit, but have picked up a 70" Top Flight chute to replace the undersized 50" main that came with it. My OpenRocket sim has been warning me of high speed main deployment, since the speed under drogue is about 77 ft/sec. With the 70" main, I'll be down to 17-18 ft/sec, vs 24 ft/sec with the 50" stock chute.
I hope to test some deployment charges tomorrow.
Thanks,
Kevin K.
 
I also chose Apogee's Level-2 rocket for my level 2 cert. and enjoyed building it. With my build I decided to only use internal fin fillets. It worked well and now I use that technique wherever possible, which can be a challenge in some builds. :wink: I also fitted the rocket with a Mobius HD camera & 3D printed shroud.

Here's my cert flight video - Rocket landed ~100' from the pad...:smile:[video=youtube;00rAdSsa37c]https://www.youtube.com/watch?feature=player_detailpage&v=00rAdSsa37c#t=0[/video]

I recently bought a second NC and fitted it with an Eggfinder GPS module and plan to fly it later this month to test the GPS system - Rocket Locator system combination. If all goes well, the next flight will be for the "Mile High" club.
 
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Kevin,
What size drogue did you go with and where did you position it in the "lineup"? Just below the payload? I could not tell from your video what your recovery looked like under the drogue.
I'm currently planning to use the stock 18" thin ripstop nylon drogue that came with the kit, but have picked up a 70" Top Flight chute to replace the undersized 50" main that came with it. My OpenRocket sim has been warning me of high speed main deployment, since the speed under drogue is about 77 ft/sec. With the 70" main, I'll be down to 17-18 ft/sec, vs 24 ft/sec with the 50" stock chute.
I hope to test some deployment charges tomorrow.
Thanks,
Kevin K.

Kevin - sorry I missed this. So I used the drogue that came with the kit. I replaced all the harness gear with Kevlar gear from onebadhawk. Teddy rocks!! I put the drogue on his "third loop" configuration.
 
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