Kit recommendations for 38mm Min Diameter

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A-N-D-R-E-W

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Hello TRF,

I'm looking for insight into my next project, a 38mm minimum diameter rocket.
I've already acquired the motor (Loki 38/1200). I'm planning on putting the K627 in it.

Current thoughts:

-Wildman Blackhawk 38
It comes with beveled fins and has a 32'' air frame.

-Madcow Mongoose 38
Carbon fiber and has a 30'' air frame.

Concerns:
-I've been looking into and reading up on tip to tip reinforcement, and debating if it would be needed for 1 flight on the Loki K627.
-If I could snag one of the madcow black friday specials it would actually be about 30 dollars cheaper than the blackhawk...
-I would be losing 2'' of with the mongoose.
-If you were going to build one or the other. Which would it be and why.
 
The decision is clear--Madcow has a promotion for the Carbon Fiber Mongoose 38 starting 7am Pacific on Friday--price is an unbelievable $99.

From the Ether...
 
Well if they run out of stock I guess the losers can scratch build a better preforming rocket by customizing the length of tubing to components used. Either kit should go out of sight, rip non tip to tip fins off, leave a smoldering hole in a wallet, huge grin on face, and require a quality tracker to find again.
 
Lotta carbon fiber going to missing with K627's, including mine.

Carbon fiber hates RF signals. Acts like black hole to radio wave. Lol. Designed a Von Karman nose around a tracker once... Worked a lot better than that kit crap solid nosecone stuff. Maybe in 38 you can buy a hollow nosecone of fiberglass, and put a bay in it.
 
Maybe in 38 you can buy a hollow nosecone of fiberglass, and put a bay in it.
I don't know for sure, but the I'm guessing the Mongoose as a FW glass nosecone. If it's roughly like their other 38mm FWFG VK ones, it has plenty room for a tracker.
 
I don't know for sure, but the I'm guessing the Mongoose as a FW glass nosecone. If it's roughly like their other 38mm FWFG VK ones, it has plenty room for a tracker.
Correct...

Kit includes:

38mm Black Fiberglass Filament Wound 5:1 Von Karman Nosecone / Green Tip
38mm Carbon Fiber Airframe 30"
38mm Carbon Fiber Airframe 16"
38mm Carbon Fiber Switch Band 1"
38mm Carbon Fiber Coupler 7"
2 Aluminum 38mm AV Lids
Nose Cone Bulk Plate and Coupler
3 Carbon Fiber 3/32" Thick Fins
Fin Alignment Guides



From the Ether...
 
No T-T needed on these 38 screamers. Just the right glue, nice fillets & all is well in "Speedy" town. :dark:
 
Madcow/RW GoDevil 38 will do the job too. Below link is to my build thread and flight report for the K627. Long story short, Mach 2.3, 16.9k. Good times. I did T2T because the fins for the GoDevil were really more flexible than I felt comfortable with. It adds very little weight, so not really a reason not to do it if you want to. To T2T or not is always a debate, you will see it consumes about 1/4 of my thread.

Build and Flight: https://www.rocketryforum.com/showt...-Leaned-to-Stop-Worrying-and-Love-3D-Printing
 
Madcow/RW GoDevil 38 will do the job too. Below link is to my build thread and flight report for the K627.

Build and Flight: https://www.rocketryforum.com/showt...-Leaned-to-Stop-Worrying-and-Love-3D-Printing

I’ve searched and read almost all build threads on 38 min diameter builds. I know for sure I’ll be using some of the techniques you used in your build. And believe it or not, I got to see your little rocket Fly at air fest this year! That thing sure did disappear fast!
 
Madcow/RW GoDevil 38 will do the job too.
Yup, the GD38's thin-walled fiberglass tube should be plenty strong for anything you can put in it. (That's a challenge to make a stronger 38mm motor, Scott!) Those fins feel too flexible for me too though - I'm cutting carbon fins on the GD38 I'm currently building. I'm not one to build things stock though...
 
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I’ve searched and read almost all build threads on 38 min diameter builds. I know for sure I’ll be using some of the techniques you used in your build. And believe it or not, I got to see your little rocket Fly at air fest this year! That thing sure did disappear fast!

Cool. Glad you liked the flight. These little screamer rockets are fun, and relatively cheap to build and fly.
 
Which glue is right for this?

Hysol EA E 120HP [don't buy the mixing wand, just use cup/cardboard.] flown to M-5 no T-T
Hybrid CTi rocket

3M ScotchWeld DP420 flown to M-3.6 no T-T
3in Minimum flown on M-2245

West 105 [105 hardender] 38mm to M-2.6 with 406 filler no T-T
Fins 1/16 carbon plate, I would do same for your 38 project. it's really cheap in that thickness.
 
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Hmm, the good ol' Blackhawk38 is not getting much love in this thread. Sure, it is not sexy carbon fiber, but it is a tough bird to get the job done. The fins are beveled, thick, and rock-solid. No need for T-T. I built mine with RocketPoxy and flew it M1.5 on a J-something to 14,000 ft. It can handle much much more.

The additional length was a plus for me, as I was planning for a 6XL case, retention, dual deploy altimeter bay, and another payload bay for the tracker.
 
Hmm, the good ol' Blackhawk38 is not getting much love in this thread. Sure, it is not sexy carbon fiber, but it is a tough bird to get the job done. The fins are beveled, thick, and rock-solid. No need for T-T. I built mine with RocketPoxy and flew it M1.5 on a J-something to 14,000 ft. It can handle much much more.

The additional length was a plus for me, as I was planning for a 6XL case, retention, dual deploy altimeter bay, and another payload bay for the tracker.

Correct about this.
When you factor in BlackHawk coming with Kevlar shock cords, aluminum BP's, Chute, and high temp Epoxy, alignment guides that ARE accurate, and thicker fins 3/32. Makes the extra few bucks worth it.

I also have one, I've beat the hell out of. By the way, fins are same as Mongoose. For all intents, it's a Mongoose clone, made of fiberglass, so no worries about RF transparency.
 
The Blackhawk38 was my first MD. Great flyer & no need for T-T. I used proline 4500 for filets, several flights and fins still rock solid!
 
How much lighter do folks think the mongoose 38 will be than the blackhawk? I'm in the middle of building a blackhawk 38 (great kit by the way!), and for example if the blackhawk is 2lbs loaded except motor and the mongoose is 1.5lbs loaded but motor, that's the difference between 75Gs and 95Gs off the pad on an I800 (which I believe will give the highest acceleration I can get from a CTI motor in one of these).
 
I'm trying to figure out which one I want also, but I think CJ helped make up my mind. I like the longer booster and all the other extras you get with the BH38.
I'm keeping my fingers crossed that Tim will have a Black Saturday deal on Blackhawks. :wink:
 
How much lighter do folks think the mongoose 38 will be than the blackhawk? I'm in the middle of building a blackhawk 38 (great kit by the way!), and for example if the blackhawk is 2lbs loaded except motor and the mongoose is 1.5lbs loaded but motor, that's the difference between 75Gs and 95Gs off the pad on an I800 (which I believe will give the highest acceleration I can get from a CTI motor in one of these).


Well...I've done it...2wice!!! BH-38 won both times!

Here is link to post describing the first time, with weights of both Goosey & BH motors, altitudes etc.

https://www.rocketryforum.com/showt...wk-prototype-first-look-!&p=143314#post143314

This is also the build thread from which I did the instruction manual.
As far as the race, I weighed 4.7lbs loaded vs Goose 4.3 loaded
CTI 6xl Bluestreaks were used.
BH went 12,188
Goose 11,001

I beat by 1,187ft. He got me off the pad by a teensy bit. BH on right.

CJDarrylDrag.jpg

passed him still in view going on to the win. Sometimes being heavier gets you closer to optimum weight & you coast farther. If looking for speed, lighter is always better.
Looking for altitude optimum weight always goes higher.

100_8206.jpg

That was 2010....almost 8 yrs ago!!!

Since then, you can deploy out the NC and shorten rocket quite a bit, getting even more out of one. I actually love flying it on 2-4 grain 38's, goes plenty high on small cheap motors.
AND I have always used friction fit & a single wrap of aluminum tape to hold motor in place.
smaller altimeters, nose cone BP's and thinner allthread [# 8] make things much simpler now.

Good luck and enjoy which ever project you decide on. Both are nice rockets.

Edit: I just finished going back & reading my build thread. Several things have changed, such as NC is no longer molded, now you get a spiral wound one, with a coupler & BP. Old version you glued some cord in for recovery attachment. So when reading, the one you get, will have all the updated [newer] parts. One of the biggest advantages the BH has....no interference with GPS/RF tracker from carbon...because it's regular glass..LOL
 
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That's a great picture.

What's the wall thickness on the BH tube? And does it only work with Wildman-sourced nose cones? I haven't played with any of the wildman kits yet.

For what it's worth, the lightest tubes I've found are the Madcow thin wall G12 like in the Go Devils. Its 0.040" wall thickness is lighter than the 0.063" carbon Mongoose tube (I'm assuming the tube is same one as the 38mm tube in the components section of the store). I don't think there's any flight related structural reasons for using carbon vs glass in a 38mm, but that carbon sure is pretty!
 
Carbon looks really cool, and I love it dearly, but the Rf blocking is a real PITA if you don't need the strength. My CF 54 Mongoose is awesome, but I would have built it differently if I could have housed the tracker anywhere but the NC. For 38 you aren't going to need the CF...you can even smack the thin walled GoDevil fiberglass really hard, like Loki 38-1200 hard. The CF sure is pretty though.
 
I managed to get one of the $99 mongoose 38 but need a rocksim file for it. Anybody have a link to one? I could modify the Blackhawk one but it would be easier if I can get the right one.
 
Madcow/RW GoDevil 38 will do the job too. Below link is to my build thread and flight report for the K627. Long story short, Mach 2.3, 16.9k. Good times. I did T2T because the fins for the GoDevil were really more flexible than I felt comfortable with. It adds very little weight, so not really a reason not to do it if you want to. To T2T or not is always a debate, you will see it consumes about 1/4 of my thread.

Build and Flight: https://www.rocketryforum.com/showt...-Leaned-to-Stop-Worrying-and-Love-3D-Printing

I thought the K required that one ask for a longer sustainer tube to accommodate that motor? Mine I just used Proline 4500 fillets and it's good to go for the 720 case I sized it for. Being a Midwest flatlander, not many venues nearest me could deal with it. (Yeah I know KLOUDBusters is a possibility but a long way to drive for a little rocket.)

I built a stretched Wildman 12 years ago and used a 10" coupler for an ebay:

WM3.jpg

I couldn't fit two altimeters and a Beeline GPS in there at the time and flew it with one altimeter. Nowadays, could buy a new NC, cobble it for a nose tracker and stuff two deployment devices in a capricious ebay. I have a Loki L2050 to fly it on and that is the same case for the
54MM M. Again, it would end up going pretty high so that's the issue. Kurt
 
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