What's better than a Polecat 7.5" Thumper?

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dixontj93060 said:
A quick update... We are in the middle of the PBS (Pretty Boring Stuff) channel on this build right now. Doing internal and external fillets as we speak. Typical T-88/milled FG/chopped FG combo and embedded dowels internally; mid-cure and microspheres externally.

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Will there be a ring going over the top of the tube?
I am tihnking that the charge would damage the electronics if left exposed.
 
I am pretty sure the first thumbnail photo and airstart that you talked about were at TCC in August. If so, my Polecat 5.5 inch Nike Smoke was a couple of pads away from yours. Your flight was very cool.
 
Nice build. The Polecats are great rockets. I have also talked to Jack about some of his bigger rockets that are not listed any more. Jack told me that he will build more when he gets the time.
 
MasonH said:
Will there be a ring going over the top of the tube?
I am tihnking that the charge would damage the electronics if left exposed.
Click to expand...

Yes, here is a similar angle with the fore ring now installed. I wanted to get good internal fillets and sandwich the fin tabs nice and tight. But the Thumper fin tabs are only 12" or so while the root edge is nearly 18". Thus I put an additional aft ring at the bottom of the airframe so that it along with the (normal) bottom ring butted up against the aft edge of the fin tab, gave me just enough support to epoxy in the MMT assembly and be able to remove the fore ring to install the internal fillets. Typically much easier to do from the rear, but couldn't really in this case.

009 (1280x960).jpg
 
Av-bay in progress, about halfway completed. Now that I have everything fitted and measured, I feel comfortable going ahead and epoxying in the av-bay coupler (and it is now curing in front of my office bathroom space heater). Yes, Polecat provides a shortish 9" av-bay and they recommend you glue it into the main/payload bay. Actually they recommend gluing it and the fore bulkhead into the bay. After much thought and testing the dexterity of my arm/hand, I decided to keep the bulkhead separate and just attach the coupler only. Given that the coupler only extends 2-3/4" into the airframe (Polecat says to do 4" but no freakin' way am I only leaving 5" to couple into the booster), I am adding four #8 screws through the airframe and into mounted t-nuts that cinch down and provide additional assurance that the fore bulkhead is secure. Finally, you might also notice the dark color of the coupler as I took the extra epoxy/milled FG mix and soaked it into the exposed coupler areas.

20130207_134022.jpg
 
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dixontj93060 said:
Av-bay in progress, about halfway completed. Now that I have everything fitted and measured, I feel comfortable going ahead and epoxying in the av-bay coupler (and it is now curing in front of my office bathroom space heater). Yes, Polecat provides a shortish 9" av-bay and they recommend you glue it into the main/payload bay. Actually they recommend gluing it and the fore bulkhead into the bay. After much thought and testing the dexterity of my arm/hand, I decided to keep the bulkhead separate and just attach the coupler only. Given that the coupler only extends 2-3/4" into the airframe (Polecat says to do 4" but no freakin' way am I only leaving 5" to couple into the booster), I am adding four #8 screws through the airframe and into mounted t-nuts that cinch down and provide additional assurance that the fore bulkhead is secure. Finally, you might also notice the dark color of the coupler as I took the extra epoxy/milled FG mix and soaked it into the exposed coupler areas.

View attachment 117094
Click to expand...

Off topic, but be aware of using the space heater to cure your epoxy. I have become quite sensitive to epoxy over the years and heating it definitely causes the hydrocarbons to float more. If you're around people that are equally sensitive it can give them a pretty nasty headache. May spread an ammonia like smell, too.
 
patelldp said:
Off topic, but be aware of using the space heater to cure your epoxy. I have become quite sensitive to epoxy over the years and heating it definitely causes the hydrocarbons to float more. If you're around people that are equally sensitive it can give them a pretty nasty headache. May spread an ammonia like smell, too.
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Dan thanks. It is actually pretty mild heat when set on it's lowest setting.
 
dixontj93060 said:
Av-bay in progress, about halfway completed. Now that I have everything fitted and measured, I feel comfortable going ahead and epoxying in the av-bay coupler (and it is now curing in front of my office bathroom space heater). Yes, Polecat provides a shortish 9" av-bay and they recommend you glue it into the main/payload bay. Actually they recommend gluing it and the fore bulkhead into the bay. After much thought and testing the dexterity of my arm/hand, I decided to keep the bulkhead separate and just attach the coupler only. Given that the coupler only extends 2-3/4" into the airframe (Polecat says to do 4" but no freakin' way am I only leaving 5" to couple into the booster), I am adding four #8 screws through the airframe and into mounted t-nuts that cinch down and provide additional assurance that the fore bulkhead is secure. Finally, you might also notice the dark color of the coupler as I took the extra epoxy/milled FG mix and soaked it into the exposed coupler areas.

View attachment 117094
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Looking good.... I think it was something just like this that lead to the tomato sauce can insert idea!!
 
AHansom said:
Looking good.... I think it was something just like this that lead to the tomato sauce can insert idea!!
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Yeah, I thought long and hard about doing this and then decided just to stick with the aft bulkplate as it is. With a three grain 75mm and many 38mm outboards I am achieving 10K in altitude--that's OK for me.
 
OK, good. Epoxy fully cured on av-bay assembly. Sanded coupler lateral face smooth and got nice fit with the booster. Also located and drilled the four #8 holes in payload tube for stainless truss head screws for even extra support in fore av-bay bulkhead.

20130208_142916.jpg
 
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Thanks Kehoes23.

Finished (final) various holes and plugs for the airframe (alignment marks, shear pins, et. al.)

025 (960x1280).jpg

Started working on av-bay wiring this weekend. Also need to begin working on recovery--chute selection, sewing harnesses, etc. But as any of you that have had a Polecat kit before know, I still have much work ahead finishing this "rough" fiberglassing job to something I deem acceptable.
 
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First overall fill and sanding complete. Super-Fil on I'd say 85% of the surface area and now after much sanding 98% of pinholes and undulations filled/smoothed. Of course, the more subtle ones will show up after the first shot of Filler-Primer, but that's to be expected. Only major thing done while going through fill and sand step was to drill three 1/4" sampling holes for av-bay (two of which provide access to pushbutton power switches).

20130228_135954.jpg
 
The only thing better than a 7.5" Thumper is a 10" Thumper with a 48" extension ^.-. May have to post sometime, love your thumper.
 
Finishing up some details in the nosecone to accomodate for up to 3 lbs of nose weight. All-thread with fender washer assembly and two metal cross pins encased in a slurry of slow epoxy and generous supply of milled and chopped fiberglass.

20130304_084534.jpg

Used the supplied nosecone bulkplate. I probably would have made it wider diameter so it isn't so deep into the nosecone. I will definitely have to use a pilot chute on my deployment bag positioned just right so the recovery doesn't get stuck in the NC. Also typically I would attach a forged eye directly to the all-thread, but since it was set up with a u-bolt, I will try it and see how it goes.

20130304_172743.jpg
 
First coat of Filler-Primer applied. Taking a look at the surface I'm pretty happy with fill and sanding.

20130308_172536.jpg
 
Still making progress here. Picked out recovery items including a 8' Rocketman main and a Skyangle drogue. Cut and sewed loops in two 24' sections of 3/4" nylon shock cord (w/Nomex protection on one end) using Kevlar thread.

IMG_20130413_050159.jpg
 
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If you can believe it, I'm still working on this beast. Today's milestone, primer and fill is now complete. Took nearly a dozen rounds to get all the pin holes and undulations out--smooth as a baby's butt now. I know, I know, stupid; not even really a performance rocket, but hey, I get anal about finishing these things.

20130605_170207.jpg
 
o1d_dude said:
Jack is the heart and soul of West Coast rocketry.
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+1

I met Jack for the first time up in Washington at FITS.....what a great dude. Really helpful and just drops the BS and sells you what you need, not what he needs to move out of his truck
 
AHansom said:
I some pics of your finished rocket in another thread. Looks great!!! Have you flown it yet??
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Let's just say I had a flight "hiccup". No damage or injury. Partially prep'd in my workshop and ready to fly at anytime (looking for free time and good weather).
 
dixontj93060 said:
Let's just say I had a flight "hiccup". No damage or injury. Partially prep'd in my workshop and ready to fly at anytime (looking for free time and good weather).
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Well... technically it DID fly. And you should have won closest to the pad.
What was the altitude on that flight? Almost 20 or 25 feet?
Seriously, glad you were OK and nothing bad happened to you, bystanders, or rockets.
Thunderstruck 5 will be here soon, then you can shake out those cobwebs...

Adrian
 
jd2cylman said:
Well... technically it DID fly. And you should have won closest to the pad.
What was the altitude on that flight? Almost 20 or 25 feet?
Seriously, glad you were OK and nothing bad happened to you, bystanders, or rockets.
Thunderstruck 5 will be here soon, then you can shake out those cobwebs...

Adrian
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Hey, hey, hey... 100 ft (not 25 ft)... Problem was at one time it flipped and pointed right at us. :y:
 
Hey it will go well . Are you waiting till thunder struck or at one of the club launch
 

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