My path to level 2. A painkiller, a Scion, and a whole lot of time. (Successful!)

After having two failed attempts I chose to fly with a lower power motor as a shake down. It was so much fun, the shakedown turned to three flights. I had high confidence that any failure would be due to a Cato.

I also came very close to buying a DMS motor just to avoid assembling the motor for the flight. But, I had the load and trusted that any mistakes would be caught.


Kirk

Ok, here's the big question. Do you guys want me to go through the mid-power builds too in this thread? Or should I break them out into different threads?
I've decided to add another rocket to the mix.... a 29mm Mega-Mosquito. The max target motor for that build is the CTI 143G33 'Mellow'.

-Hans

HHaase said:

Ok, here's the big question. Do you guys want me to go through the mid-power builds too in this thread? Or should I break them out into different threads?
I've decided to add another rocket to the mix.... a 29mm Mega-Mosquito. The max target motor for that build is the CTI 143G33 'Mellow'.

-Hans

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Keep it going here... Your part to level 2...

Ok, so today is cold and windy here in the Dakotas, first freeze of the season happened last night. I was hoping for less wind, so I could head up to Dad's farm to fly the QCC.... oh well, I got 15mph gusting to 20. Decided to get building on the Mega Mosquito. I have actually been slowly laminating the fins over the past week or so, but today was time for the motor mount. I picked up the 11" 29MM BT-80 kit from Sunward, not because I needed an 11" mount, but more because I wanted the three centering rings and ability to trim to length.

I loaded in all the recovery gear into the empty body tube, inserted the nose cone, and then used that to figure how long of a tube I could fit. I did back off about an inch for a bit extra space. Ended up with a 5.25" long motor tube. Then came a lot of test fitting, measure measure measure again until I figured out where the top and middle centering rings should go. Notched the top one to fit the kevlar shock cord, and tacked them in place with CA. Measured again to make sure they were where I wanted them, and epoxied those together. For this build I'm using West Marine G-Flex. For no real reason other than I have it already.

Once that was cured long enough, I did more test fitting with the body tube and fins, until I knew for sure where the rear centering ring would go. Then I figured in the Estes threaded retainer, cut the motor tube to length, and am currently waiting for the top centering ring to cure in place inside the body tube. I'll epoxy the center ring at the same time as the fins, then the aft ring and motor retainer last. Still a lot of work to do on the fins before they are ready to attach I just set them out here for the photo, but the length measurements were done using the body tube and all three fins. I'll left it a hair longer so I can sand it to final length after I have the rest installed in the body tube.

One thing I forgot to mention on the previous post is that the the available length on the motor tube won't even be close to using that CTI G33 mellow. That's a 7.35" motor tube for 3 grains, and I just don't have the length available. I still will have access to a good range of CTI and Aerotech 29mm loads that are going to be a hoot.

HHaase said:

One thing I forgot to mention on the previous post is that the the available length on the motor tube won't even be close to using that CTI G33 mellow. That's a 7.35" motor tube for 3 grains, and I just don't have the length available. I still will have access to a good range of CTI and Aerotech 29mm loads that are going to be a hoot.

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Just because the MMT is only 5 1/4" long doesn't mean you can't fly a longer motor. There is nothing wrong with letting the motor extend out the top of the tube. If you have enough room below/inside the nose cone, you could fly the +14" Pro29-6GXL case

Not much room between the motor tube and the recovery gear, I made it as long as I could. Of course a section of BT-80 and a coupler would work wonders.

-Hans

Been busy building, not so busy internetting and grabbing the camera, but I do have a few.

Fins are filleted to the body tube both inside and out, and again to the motor mount plus against both centering rings as best I could. Definitely want to look deeper into the injecting method for the next couple builds.
The G-flex has the consistency of tree-sap. I didn't find it particularly enjoyable to work with for fillets, but I do like how well it penetrates and fills. I didn't snap a photo when I did the external fillets, these photos don't show it, but I did do it. These photos are when I was applying the aft centering ring.

Some elmers wood hardener to seal the fins, and CWF to fill any gaps. Sand, fill, sand, prime, sand. Right now it's drying after the 2nd coat of red paint.
Considering all the scale model building I've done over the years, you'd think I'd remember to give it a basecoat of something bright and even before hitting something with red paint.
But no, I forgot. Too late now and I'll have to deal it looking splotchy, the last thing I want to do is too many coats and add excessive weight to the thing.

I recently tried using expanding foam for filling the cavity between the motor tube and body. I love the result. Didn't add a lot of weight and locks the fins in solid. I think from there external filet is mostly for aero dynamics and looks.


Kirk

1tree said:

I recently tried using expanding foam for filling the cavity between the motor tube and body. I love the result. Didn't add a lot of weight and locks the fins in solid. I think from there external filet is mostly for aero dynamics and looks.


Kirk

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Agreed! Tip... Do your external fillets before foaming... Keeps the foam in the fin can, eliminating the need to trim any that comes out through the slots. I just did fingertip fillets on mine.

HHaase said:

Too late now and I'll have to deal it looking splotchy, the last thing I want to do is too many coats and add excessive weight to the thing.

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A couple more coats of paint aren't going to hurt you too much in the weight dept.

DizWolf said:

A couple more coats of paint aren't going to hurt you too much in the weight dept.

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When it comes to getting red to look good over an un-even base..... it's generally never a 'couple'.


-Hans

HHaase said:

When it comes to getting red to look good over an un-even base..... it's generally never a 'couple'.


-Hans

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If you're going for even, might as well go primer then red

HHaase said:

When it comes to getting red to look good over an un-even base..... it's generally never a 'couple'.


-Hans

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Yea...I did this with a pearl white once. after one coat I looked at it and just sanded it off and re primed.

What I should have done was give it either a white or silver coat first, then the red. If it was something structural I'd worry about it more. This is just cosmetic and a lesson for next time.
At this point I'll just live with it, paint a fin black, and fly.

-Hans

One 29mm Skeeter.
Now I just need a launch rod and motor, otherwise she's ready to fly.

Open Rocket is showing a very nice flight on a Apogee F10.
Peaking at just over 2200ft, max G of 7.5, and 50fps off the rod.

Fall in the Dakotas is particularly annoying with the near constant wind. The QCC is ready to go with its fresh new av-bay, Mosquito is ready to fly, I have motors in the box for both of them..... and 20mph winds every weekend. Even LPR flights are troublesome with this wind, lost the upper half of my daughters Flutter-By last week. Though to be fair I didn't look TOO hard, I got tired of re-gluing fins on it every flight.

Oh well. Once I get caught up with all these circuit board repairs I can start on the Painkiller Micro.

-Hans

Yeah, time to pack up the GSE for the season, too much snowpack now and field access just isn't possible until the drifts are gone. Assuming I ever had a combination of daylight and low enough wind to even launch.

The good news is the Micro is almost done. Just needs rail buttons and chute installed to be flyable with motor ejection. Not painted yet though. Not an overly exciting build... pretty much falls together. I will get some photos processed soon to get it up to date. Once that is done I have another MPR build to do as a Christmas gift, then time to start serious planning and initial builds on the PK3.

yea, I've packed it in for the year too. I'm halfway into my PK3 build. MMT is assembled and installed. I just need to sand the fins to fit and glue them in. I still haven't decided how to do the nosecone. We've been snowed in all week, and as much as I want to sit down and build, every effort has been on digging out the driveway.

Plan-A for converting the painkiller micro to dual deployment is a no-go. The 38mm blue tube av-bay kit is too heavy and too long at almost 11" when you factor in the eye bolts. The multiple battery requirements of the eggtimer make it too bulky, as does the big TO-220 transistors. I could probably swap to smaller hardware on the blue-tube to reduce the overall length, but don't know if I could fit the eggtimer plus its batteries inside. If I stick with going DD on this rocket eventually, I'm leaning toward a raven with active bulheads. That would also give me two independent altimeters for redundancy in the PK3 when the time comes.

I really am liking the semi-transparent nature of fiberglass tube for planning things like this, it lets me see pretty darn clearly how much volume is consumed by various components. Also lets me see the epoxy penetration very nicely as well. Like on the Mosquito, I've used the West Marine G-Flex on the interior but picked up some rocketpoxy for the fillets this time around. So much easier to work with for that purpose. The G-flex makes me think of tree sap, the rocketpoxy more like peanut butter.

cheaper option, wedge an RRC2 in the nose and use a cable cutter. I'm considering chopping the front of the tube to make a payload/nosecone and using a cutter. but with all that the weight starts to kill the whole "easy to fly" bit of this rocket.

The rrc is a thought too, though I already have a bulkhead in the nose cone. I did look into cable cutters for a while but something about them is making me skittish. Really can't place what it is pushing me away from them. Could just be that I haven't really wrapped my head around it yet. The raven is advertised to fit in a 2" long coupler with battery. Spendy, yes. Though it would sure fit the role nicely I think.

Lots of time to think though, I want a couple shakedown flights with motor deploy first and that could be a while.

Starting to dabble in open rocket to get planning on the PK3 build, and looking at motors with a basic single apogee deploy setup.

Not many 54mm motors in the H-I range, most of them are in the 200ns average impulse range, and they're all showing a bit slow off the rail for my taste.
Starting to narrow my target motor into the I300-I500 range for the L1 flight depending on the specific curve. The good thing is the local vendor for the clubs I'd be flying with handle both Aerotech and CTI, so the more options the better. I'll keep adapting down to 38mm as an open option too, just to give more motor selection.

Either way, the L1 flight looks like it's going to take a pretty stout I motor and give an apogee around 1,000ft or so.

To my knowledge, not many people flying the PK3 yet, so not much tribal knowledge to tap into yet for this particular rocket.

-Hans

in 54mm, I170G shows 39 MPH off the rail, I229T shows 47 MPH. I'd do either of those.

in 38, I245G (360 case) shows 62 MPH off the rail, and an I600R (720 case) Shows 86mph. Both really quick

Loki I405's will pull 85mph, and 3500'

thats at a build weight of 4 pounds. even adding a pound I still get good numbers on those. The I245 would be my bet at around a 2K flight.

I'm looking at a loki J820 to around 6500'

I did my 3" darkstar without the payload on an H178DM, and that thing's a tank.

I see what happened. Somehow I ended up with an override to the mass in open rocket, and it was showing just under 4kg for the empty weight. Not sure where that came from, I didn't make any changes that I can remember. That'll skew the numbers a bit for sure. Seeing much more aggressive flight profiles now with the weight situation fixed. I'm feeling much more comfortable about the L1 flight again.

-Hans

I'm strongly considering an I599N DD flight.

DizWolf said:

I'm strongly considering an I599N DD flight.

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Why stop at the 599? Step up to the 1299.

If I was going high I'd go 1799

I'm looking at short hop one grains for this..... It'll get one flight on a loki J820 though.

Anyone know the max altitude of the PK3 on full I's? I'm thinking of building one sometime.

DizWolf said:

If I was going high I'd go 1799

I'm looking at short hop one grains for this..... It'll get one flight on a loki J820 though.

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K1440 or K2045?