Nothing revolutionary or terribly exciting about this, but I was wondering if I should go with 24mm or 29mm power. It's just going to be standard surface mount fins, so I'm wondering if they'll stand up to the 29mm thrust curve. Opinions anyone?

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Bill Eichelberger
NAR 79563

http://wallyum.blogspot.com/

I miss being SAM 0058

Build floor: Estes - Low Boom SST Semroc - Marauder, Shrike, SST Shuttle

In paint: Canaroc Starfighter Scorpion Centuri Mini Dactyl Estes F-22 Air Superiority Fighter, Multi-Roc, Solar Sailer II, Xarconian Cruiser Semroc Cyber III

Ready to fly: Estes - Solar Sailer II Semroc - Earmark

Yes it will. It can even handle a small 38mm.

Step up to BT-80. Use 1/4" balsa TTW, and a dedicated 24mm mount. You will have the perfect demo bird for your B6-4 field. Use a D12-5 for windless days and you'll get a tail slide before ejection. Use a D12-3 if there's a slight breeze (YMMV according to how heavy you build). It will have slow liftoffs with lots of noise, smoke, and fire up close and personal for those who are uninitiated in rocketry, and it's pretty cool for us old timers too. Build another one with 29mm mount and ply fins for your regional flying fun.


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I love sanding.

My thinking was to go ahead with the 29mm mount as you can always step down with a 24mm adapter. Surface mount fins can be enhanced by stripping the glascine wrap and using the old FSI trick of using a small drill to make several holes along the fin line to make glue rivets. Epoxy would be the adhesive of choice.
But, you know all of that.

Chas

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Charles Russell, MSgt,USAF (ret.)
NAR 9790, Lvl 1
SAM "Balls Three"

Nope, might work with a C11, but the D12 is too much motor for the field. I tried this with a Big Daddy years ago and had to borrow a neighbor's ladder to retrieve it from the roof. You have given me an idea, though.

__________________
Bill Eichelberger
NAR 79563

http://wallyum.blogspot.com/

I miss being SAM 0058

Build floor: Estes - Low Boom SST Semroc - Marauder, Shrike, SST Shuttle

In paint: Canaroc Starfighter Scorpion Centuri Mini Dactyl Estes F-22 Air Superiority Fighter, Multi-Roc, Solar Sailer II, Xarconian Cruiser Semroc Cyber III

Ready to fly: Estes - Solar Sailer II Semroc - Earmark

Does that still work with the new Estes motor retainers? They really, REALLY need to think about the Goblin as the next PSII bird.

__________________
Bill Eichelberger
NAR 79563

http://wallyum.blogspot.com/

I miss being SAM 0058

Build floor: Estes - Low Boom SST Semroc - Marauder, Shrike, SST Shuttle

In paint: Canaroc Starfighter Scorpion Centuri Mini Dactyl Estes F-22 Air Superiority Fighter, Multi-Roc, Solar Sailer II, Xarconian Cruiser Semroc Cyber III

Ready to fly: Estes - Solar Sailer II Semroc - Earmark

I built this 196% Upscale Goblin back in 2008.
BT80 w/2 24mm D12-5 also a video of the launch I'm sure you could use E20 SU with no problem.

link here: http://www.4hrockets.blogspot.com/s...ader%20Projects

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John

NAR #91135 L1
SAM #0037

Yeah, 1100' on two D12's says 550' on one. That's WAY over the comfort zone of B6-4 Field. Nice bird. Who doesn't love clusters?

__________________
Bill Eichelberger
NAR 79563

http://wallyum.blogspot.com/

I miss being SAM 0058

Build floor: Estes - Low Boom SST Semroc - Marauder, Shrike, SST Shuttle

In paint: Canaroc Starfighter Scorpion Centuri Mini Dactyl Estes F-22 Air Superiority Fighter, Multi-Roc, Solar Sailer II, Xarconian Cruiser Semroc Cyber III

Ready to fly: Estes - Solar Sailer II Semroc - Earmark

I made a dual D12 mount for my Centuri Saturn V's which was perfect for small fields and improved flight reliability drastically. Piston launching them was "impressive".

The C SV had a ST-16 (BT-60) host mount for the 3x18mm they recommenced (duh!) which was reset into the tube to maximize the Krushnik effect. By making a mount that inserted into the ST-16 and hanging the motors just out the back, it reduced the Krushnik vacuum slightly and was adequate power for a change. I always used the clip on fins and flew with a towerless cone.

Just Jerry

The Big Daddy will need a larger chute because it's heavier, but will fly just as high, if not higher because it doesn't have 1/4" thick boat anchors for fins. I hung mine in a tree at our annual school launch, on a playground with about the same usable size as your ball field the first time I flew it. I flew my old BT-80 Goblin year after year, finally hanging it after 20 years of school launches. I'm sure can put my new Goblin up on your field and get it back. However, it should do well on a C11-3 also...it's just not quite as cool as a D12. I built a BT-80 based Red Max with 1/4" fins and it is still ascending at ejection on a C11-3. The extra length of tube and one more thick fin should slow a BT-80 Goblin down enough to eject at apogee.

I'm just looking out for you because you go to the B6-4 field two or three times a month. You won't be able to fly the heavily built model much because you probably don't go to the big fields but a couple times a year. Two speciality rockets are better than one jack-of-all trades. The jack usually ends up seriously damaged, in a tree, or lost because it's usually flown at one edge or the other of its power and/or recovery area envelope.

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I love sanding.