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  #1  
Old 10-26-2008, 11:01 PM
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Solomoriah Solomoriah is offline
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Default Mo' Skeeter

I'm starting another one... in fact, it's darn near done already: Mo' Skeeter, a 320% upscale of the classic Estes Mosquito. I'm building it as a rear-ejection model so I can avoid the visible nose cone line that most Mosquito upscales suffer from. That, and I want to test this type of rear ejection before I build a replacement for my lost Dawn Star.

I've used a Baby Bertha cone (does that make it a Goony?), 6" of BT-60, 6" of BT-20, two 20-60 centering rings, a thrust ring, engine hook, and retaining ring, and a launch lug and a Kevlar leader so far; I'll be adding a Semroc chute and a length of elastic shock cord (and probably a snap swivel) to finish it up.

The fins are 3/32" balsa, cut using a 320% upscale of the standard template downloaded from JimZ's site. I cut the pointed part and attachment lug from the nose cone, bored a new hole to attach the Kevlar, and epoxied the cone in place on the BT-60 tube. I came to regret that decision a bit later.

After notching the centering rings (inside for the engine hook on the rear ring, outside for the shock cord for the forward ring), I installed the thrust ring, engine hook, and retaining ring into the BT-20. I still had some epoxy mixed up, so I used that to secure all these parts. After gluing the aft centering ring in place using yellow glue, I put the forward ring on the tube and inserted it into the body tube, pushing it in until the aft ring was just inside the BT-60 tube. Doing this pushed the upper ring into the exact position it needed to be in. I pulled the inner tube out and applied yellow glue to secure it.

Next, I glued the fins in place using yellow glue and the usual "stick it on, pull it off, let it dry a bit, glue it on for good" method. Here's where I regretted gluing the nose cone on first... I had to hold the rocket for probably twenty minutes before I was sure the glue was solid enough to stand the rocket on its fins.

This was all done last night. This morning and afternoon, I applied several fillets of white glue (less shrinkage than yellow) then attached the launch lug with yellow glue.

I'm not fond of orange, so I'll probably paint this rocket yellow overall, then paint one fin black.

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  #2  
Old 10-27-2008, 01:14 AM
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Mark II Mark II is offline
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Great idea! It is basically a Baby Bertha with a shortened body tube and different fins. Oh, and rear-ejection, too. A Mosquito that you won't lose on the first flight - what a concept!

It looks like a very simple but also very effective design, just like the original. Sometimes you can have an easy and very obvious design or upscale sitting there, right in front of your nose, and yet you never see it. Building an upscaled Mosquito out of a Baby Bertha nose cone and a length of BT-60! [Slapping own forehead] Why didn't I think of that?

Good job!

Mark \\.

P. S. Oh, BTW, it looks like you are 7 posts ahead of me in the total post count. I've got to catch up. Grrrrrr, grrrrrr.
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  #3  
Old 10-27-2008, 07:17 AM
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Thanks for the kind words. I'm looking forward to flying this one.

If it works out, I'll replace my lost Dawn Star with a similar rocket. The original Dawn Star was rear ejection, but not using the "stuffer" design; a deployment failure caused it to come in ballistic, and it landed in a bean field. With no chute to lay atop the plants, there was no chance of finding it.

I think this design will result in a more positive deployment. However, I'm still trying to work out a no-hook, no-tape engine retainer for the Dawn Star II. I have a plan in mind but haven't tried it yet. This is an intermediate step on that road.
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Old 10-27-2008, 08:51 AM
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Only 18mm power ????
You should have upscaled the power DIAMETER 320% as well.
A 320% mosquito on 38mm J350W power would REALLY fly (to the moon) !

Honestly though, this one begs for 24mm power....one can always use an adapter to fly on 18mm.
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Old 10-27-2008, 09:26 AM
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Quote:
Originally Posted by Solomoriah
........ However, I'm still trying to work out a no-hook, no-tape engine retainer for the Dawn Star II. I have a plan in mind but haven't tried it yet. This is an intermediate step on that road.

Just a thought....I've used a loop of kevlar around the aft end of the motor and fed into the body tube (through the motor tube) and then secured to the recovery harness. Then just use a little mylar tape to hold the kevlar in place. Haven't lost a motor....but been through some kevlar . Makes it really easy to replace the recovery hardware since nothing is attached to the rocket.
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  #6  
Old 10-27-2008, 09:28 AM
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I've burned ONE 24mm engine. In my entire LIFE. I'm MUCH too cheap to buy the dang things. So 24mm power is not even in the question.

I did consider 2x13mm or 2x18mm... if I use a snap swivel to attach the stuffer to the sustainer, I can swap it out, making upgrading easy. Even a 24mm upgrade, if I decided to do it (but I won't).
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  #7  
Old 10-27-2008, 09:55 AM
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Quote:
Originally Posted by barone
Just a thought....I've used a loop of kevlar around the aft end of the motor and fed into the body tube (through the motor tube) and then secured to the recovery harness. Then just use a little mylar tape to hold the kevlar in place. Haven't lost a motor....but been through some kevlar . Makes it really easy to replace the recovery hardware since nothing is attached to the rocket.

My plan is to construct a twist-lock, similar in principle to the E2X/RTF twist-lock retainers but made of standard paper/balsa. There's an article in the Peak of Flight newsletter about making boat-tail retainers that is similar to my plan, but I won't be building it in a boattail fashion, and the retainer will twist-lock to the stuffer rather than to the sustainer.

I have some laser-cut 520 centering rings. One should work perfectly as an aft retainer stop.
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  #8  
Old 10-27-2008, 11:35 AM
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Too cheap to buy 24mm ????????
That must mean you have zero interest in AP composite RMS stuff then.
Too bad....missing out on a great part of the hobby.
I actually find the SU BP Estes engines kinda boring after getting into AP, but I still probably fly more Su BP engines than anything else because they are what I call cheap.
However I probably fly more 24mm than 18 and 13mm combined by about a 3 to 1 margin unless the 18mm is clustered/staged.

Some people love the smell of burnt BP engines....I think it smells about as good as Sauerkraut, beer, and limburger cheese-laden flatulence.....not something I want in my FACE.
Burning/burnt AP propellant smells MUCH better.
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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL
, if you have to ask what is "NORMAL" , you probably aren't !

Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !
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  #9  
Old 10-27-2008, 12:19 PM
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Not opinionated, are you?

I have a 500' square regular launch area. I'm looking at a 1000' square area, which is public land and probably only available in the Spring. APCP would be a bit much for my launch fields.
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  #10  
Old 10-27-2008, 02:18 PM
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On the bigger rockets you have the RMS24 D, E, and 55n-sec baby-F loads should not be a problem in 1000' square.
The D loads should not be a problem in the 500' square for draggy large rockets in the "Big Daddy" size and you would be okay with the E loads in "Maxi Brutes" the size of an Estes Saturn V, 1B, or V2/Pershing 1A. The D15T RMS24 reload is only 2n-sec higher than a D12, but gets things moving a LOT quicker.
The 18mm D24 load is GREAT in the Estes/Semroc Mars Lander if you add 1/2 oz noseweight to compensate for the additional engine casing weight.
That is the ONLY engine I fly mine with that is not OOP.
I put in at least a couple of flights a year on OOP C5-3's and Cox D8-3's but the C5-3 is getting rare and the D8-3 is mostly hoarded by collectors....I still fly 'em !
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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL
, if you have to ask what is "NORMAL" , you probably aren't !

Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !
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