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#1
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Binder Design Stealth Build
Well we're at it again! Haven't even flown our 2.6" Mad Cow - Tomach and off we go to the next build project.....
This time the Mad City Flyers Skunk Works is building a Binder Design 4" Stealth. Found a guy selling an old kit for 1/2 price and couldn't resist. We are thinking that this could be the rocket for an L2 cert attempt next spring. To support an L2 motor here's the upgrades we will be making to the kit:
The final height should be around 6 feet with the AV bay inserted and weight around 5.5 lbs. We've already got an H178-DM for first flight. More pics to follow as we start putting it all together! Matt and Nate |
#2
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hmm, are you going to MWP? if so maybe you should get about 5' of flat braided Kevlar from Tim for use from the motor mount to the forward end of the body, and a nomex chute 'hanky' to protect the nylon cord + chute.
Rex |
#3
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Hi Rex,
Yes we are planning to fly the 2.6" FG Tomach on our I-357 at MWP on Sunday. Tim's trailer is dangerous as it has all the goodies and the incentive of no shipping charges.... this leads to overspending my allowance. We have been adding Nome parachute protectors to all of our Mid and High power rockets in addition to a handful of dog barf. We have a Giant Leap Rocketry Fireball that we might just insert in the booster to minimize the chances of a zipper. We will also CA coat the inner cardboard tube ends to add strength. Got the fins all sanded (100, 150, 220, 320 grit) and they are smooth as glass. The booster tube comes marked with lines for the fin slots and the lug/rail buttons. After very careful marking of the fin slots using a T square we got the slots cut out. We'll get the motor mount built next. BTW, we thought your PVC launch pad was quite nice and did a great job! Cheers, Matt and Nate |
#4
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15/15 rail guides are required if your rocket weighs more than 50 pounds, unless you are planning to put a lot of weight in the nose cone you will want to use 10/10 guides.
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#5
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Good to know! If there is no benefit we'll use the 1010 rail buttons. Appreciate the guidance.
Matt |
#6
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Made some progress over the past couple of days:
This weekend should provide some time for CA coating of the tube ends and motor mount assembly. Cheers, Matt and Nate |
#7
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Love hate relationship with 6 minute epoxy
Only 1 soccer game this weekend so we made some more progress on the Stealth. We used the Great Planes 6 minutes epoxy. I think our resin was a little old as it set up in more like 2 minutes, which made for a race to get all the pieces we were attaching set properly.
Because we chose to convert the rocket to dual deploy we had a bit of a build challenge with the payload section, nose cone and bulkhead. The original design has the nose cone friction fit (or glued) to the payload section and then a standard bulkhead and anchor eyebolt is provided for the recovery cord/parachute. The AV bay prevents the placement of the bulkhead in the payload section so we fortunately had some extra 4" heavy wall body tube to create a small 4" extension from the nose cone. We then placed the bulkhead in the body with the eyebolt. So our Stealth is now over 6' with the addition of the AV bay and extension of the nose cone. On to fin fillets----- Cheers all, Matt and Nate |
#8
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Fillets and more fillets
Managed to get a little more work done on the Stealth:
We are still very happy with the method of creating external fillets that uses the following formula:
We mix the resin and harder first, then the microfibers, then the micro balloons. The resulting maroon paste is very easy to work with and sets up nicely. To date we have never seen a fracture line in any of the fillets we've set with this mixture. To create the very smooth and even initial epoxy set we soak a short piece of 1"PVC in rubbing alcohol and slowly drag it through the groove between the fin and body wall. You have to be ready to wipe up the extra epoxy that oozes out the back. After set up its lots of sanding and then filling the gaps with wood filler. Plan for this beast is our L2 certification on a J425R!!! Should get the AV bay built over the Xmas break. Cheers all, Matt and Nate |
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