Super Big Bertha----What a Pain To Build!!!

[tfrielin]

Maybe I'm just cranky today, but I'm half way through building the Super Big Bertha (Estes Series II) and I'm really exasperated with some of its build features:

1) What's the deal with making the parts count so high on the fins? When you take the outer fin, then glue on that little extra piece, then do the same for the other side outer fin piece, then glue both of them to the center fin part to make one fin, you've got five pieces for one fin. Times four fins, you got a parts count of twenty, when you could have had just four---for four fins made to the proper thickness. Instead you had to assemble twenty parts. Crazy.

I'd accept that the fin build-up was required for the extra strength it presumably gives you for flying on F engines, but if that's the case, then why is the engine mount so flmsly----those cheap cardboard centering rings instead of wood?

2) Then there's the totally gratuitous step of having to cut in the slots into the body tube for the fins to go through. Really? Did I really need to cut out the fin slot template, tape it to the body tube so I could then cut the slots out?

And, once you've got that far, the directions give no admonition to test fit the fins into the engine mount before you glue the thing in---just to make sure the fins will fit in the engine mount slots, avoiding a botch job if they don't fit. I wonder ho many novices got that far only to be disappointed that you didn't line it all up correctly?

I swear, if Estes wanted to actively dissuade a young or a novice builder from ever bothering with another rocket build, they couldn't have designed a kit with so many gratuitous, extra steps.

Or is it just me, being cranky and all??


I've got the fins nearly on now, so I'm home free for the rest of the build---I hope.

 

[Sluggo]

Sounds sketchy to me. I wouldn't like that, either. Dyna Star models sometimes have the fins in pieces, as many as 3 or 4. I've sort of moved on from models designed this way. Ply please. Am I cranky too.?? No. Its a fact that those builds are a ...... PITA.

 

[tfrielin]

Sounds sketchy to me. I wouldn't like that, either. Dyna Star models sometimes have the fins in pieces, as many as 3 or 4. I've sort of moved on from models designed this way. Ply please. Am I cranky too.?? No. Its a fact that those builds are a ...... PITA.

And I left out that they say to use CA glue to glue the outer fins to the center fin part. I was a little skeptical that the runny CA glue would do a proper job there, so I went to the trouble to use epoxy to finish the fin construction. Someone else here suggested doing the same, so I made extra work for myself there, but I bet it was the right thing to do not using CA.

 

[Scott_650]

Hmm.. I enjoyed building my SBB - I’ll have to go back to the instructions to see if I can understand your POV...

 

[rharshberger]

Sounds sketchy to me. I wouldn't like that, either. Dyna Star models sometimes have the fins in pieces, as many as 3 or 4. I've sort of moved on from models designed this way. Ply please. Am I cranky too.?? No. Its a fact that those builds are a ...... PITA.

Well...the Super Big Bertha is a PRO SERIES II kit, and not something a rocketry novice really needs to be building unless they have solid modeling skills.

 

[BEC]

I don't know whether to tackle this or not.

1. This is a Pro Series II kit....it is not aimed at a beginner. (As Rich beat me to noting)

2. The layered fins make fins that look right (thickness-wise) but are light and strong.

3. The model is designed to fly on E16 and F15 29mm black powder motors, so the weight is important.

4. Paper centering rings are more than adequate for the intended motors (see point 3)

5. Have you priced wide balsa sheets lately? The two-part outer skins allow them to be made from more affordable sheet stock.

6. Cutting fin slots is kind of a pain, I agree....but since you're cutting them yourself why would you need to be directed to try the fit before adding glue?

7. Medium CA would work as directed. I used wood glue, weights and patience.


The Super Big Bertha makes a light model that does gorgeous flights on the recommended motors.

 

[DeepOvertone]

The SBB one of my favorite builds! Yes, it’s not snap together plastic parts... it takes some doing.

 

[tfrielin]

The SBB one of my favorite builds! Yes, it’s not snap together plastic parts... it takes some doing.

I didn't expect a RTF exactly, but I thought this kit design was wanting.

And I've been building Estes rockets since the Johnson Administration.

 

[Scott_650]

I will agree that the two piece skins for the fins seems like an unnecessary complication - it’s probably due to dealing with the size of balsa sheet they needed to use due to cost and/or packaging requirements.

Cutting fin slots is probably a step or two above what a beginner builder would be familiar with but I didn’t find too difficult - I’m not a beginner but I haven’t slotted very many tubes so I did practice on a scrap tube (plus my fillets covered up my less than sure handed cuts).

I don’t use CA much for structural bonds, just details and tacking parts in place before final glueing - my fins were built up using Elmer’s Glue All, then pressed until dry, stack sanded square then papered so I don’t have an opinion on using CA for that step. I’d never use CA for wood to wood joints anyway but it would probably work ok.

After looking at the instructions again and thinking through my build I’m on the “pro” side for the PSII SBB - I liked the build and love the way the rocket flies.

 

[tfrielin]

I will agree that the two piece skins for the fins seems like an unnecessary complication - it’s probably due to dealing with the size of balsa sheet they needed to use due to cost and/or packaging requirements.

Cutting fin slots is probably a step or two above what a beginner builder would be familiar with but I didn’t find too difficult - I’m not a beginner but I haven’t slotted very many tubes so I did practice on a scrap tube (plus my fillets covered up my less than sure handed cuts).

I don’t use CA much for structural bonds, just details and tacking parts in place before final glueing - my fins were built up using Elmer’s Glue All, then pressed until dry, stack sanded square then papered so I don’t have an opinion on using CA for that step. I’d never use CA for wood to wood joints anyway but it would probably work ok.

After looking at the instructions again and thinking through my build I’m on the “pro” side for the PSII SBB - I liked the build and love the way the rocket flies.

My grumpiness is probably conditioned by the fact that I just finished building the Estes Doorknob and I found that a "normal" build for its difficulty class, which I guess is the same as for Super Big Bertha. I think.

Doorknob had none of these gratuitous "extra" steps or parts count to build. So, I found Big Bertha lacking by comparison.

Mind you, I'm not exactly a lazy builder---next I'm going to build my third Nike Smoke--the big one, not the small one. Now that's a good flyer. And a straight forward build...

 

[caveduck]

This is a classic case of what Estes has been forced into to use offshore manufacturing. The balsa fins aren't solid b/c they won't fit on a standard width balsa sheet. One-piece plywood fins would be way better, but Estes can't use plywood from China b/c the USA CPSC apparently classifies them as a toy company that must use non-toxic materials throughout, and the offshore plywood doesn't qualify. So, built-up fins. Not terribly complex if you've ever done any balsa airplanes though. It would be tempting to Monokote them just to complete the look.

I have no idea why the tube isn't pre-slotted; that is below standards for MPR kits these days. Might have to do with the expense of automating tube handling for the rotary stage in a laser cutter? I know at least one local manufacturer that has an ingenious multi-tube rotisserie fixture for his laser that allows doing some number of tubes at once. There's really no excuse for that one except the manufacturer lacking the capability.

It's on my list to build some kind of SBB but I'm gonna do it from scratch with a beefier LOC tube, plywood fins and a 38mm motor...no kit will be harmed.

 

[neil_w]

I will agree that the two piece skins for the fins seems like an unnecessary complication - it’s probably due to dealing with the size of balsa sheet they needed to use due to cost and/or packaging requirements.

There's no "probably" about it. Any time the fins would be too large for a normal (i.e. "cost-effective") sheet of balsa they are split into multiple pieces as needed to fit. Plywood fins would not have this issue, but would add a lot of weight, which they were trying to avoid.

Recommendation for CA to make the fin sandwiches is presumably to avoid the warping that would occur with wood or white glue, and the subsequent pressing that would be required. I see no reason why CA wouldn't hold those fins together just fine, as long as the leading edge is well sealed.

 

[Scott_650]

I don't know whether to tackle this or not.

1. This is a Pro Series II kit....it is not aimed at a beginner. (As Rich beat me to noting)

2. The layered fins make fins that look right (thickness-wise) but are light and strong.

3. The model is designed to fly on E16 and F15 29mm black powder motors, so the weight is important.

The Super Big Bertha makes a light model that does gorgeous flights on the recommended motors.

Bernard hit the target - ALL the current PSII rockets are designed to fly within the standards Estes sets on both 29mm and adapted 24mm BP motors - they must be designed to keep weight as low as possible while being strong enough to stay together. Unlike the mid 2000s kits with plywood parts - those were designed to fly on relabeled Aerotech composite motors (the smallest recommended motor for the #9705 Mega Der Red Max was a 29mm F50 which has a bunch more thrust than an Estes BP 29mm E16/F15 or 24mm E12). So to keep stuff light we get multi piece balsa fins and card stock centering rings. I’m good with that since there’s plenty of heavier duty rockets from other vendors out there but I can see how if you’re thinking the SBB is in the same class as a Leviathan it could be a bit frustrating.

 

[Cape Byron]

One-piece plywood fins would be way better, but Estes can't use plywood from China b/c the USA CPSC apparently classifies them as a toy company that must use non-toxic materials throughout, and the offshore plywood doesn't qualify.

That's interesting.

 

[caveduck]

Good point there, it's also the motors forcing lighter weight since Estes stopped OEMing the Aerotech ones.

 

[Scott_650]

Recommendation for CA to make the fin sandwiches is presumably to avoid the warping that would occur with wood or white glue, and the subsequent pressing that would be required. I see no reason why CA wouldn't hold those fins together just fine, as long as the leading edge is well sealed.

The “warp factor” hadn’t occurred to me - pressing fins flat is just something I do when it needs done. So yes, using CA would minimize the chances those big multi piece fins would warp. Good idea to keep the instructions simpler and the build light.

 

[Scott_650]

It's on my list to build some kind of SBB but I'm gonna do it from scratch with a beefier LOC tube, plywood fins and a 38mm motor...no kit will be harmed.

I’ve enjoyed running sims on the Animal Motor Works 4” Super Big Bertha Plus so I definitely see the appeal!

 

[rcktnut]

Other than adding a retainer and making it harder to build looks like a regular SBB. I have the regular one (2165) built stock and it flies great on the Aerotech E18 - E20 and F44's. The fins are surface mounted and have the gussets. I personally like the look of the gussets. I guess Estes just needed the build more complicated to place it in the PSll category.

 

[Sluggo]

I think I'm learning something here. I have an Estes Doorknob. Because the Doorknob comes with a 29mm motor tube, I assumed it could handle any 29mm motor. Am I wrong in assuming that.??

 

[rharshberger]

I think I'm learning something here. I have an Estes Doorknob. Because the Doorknob comes with a 29mm motor tube, I assumed it could handle any 29mm motor. Am I wrong in assuming that.??

It should handle most any 29mm motor except maybe some hard hitting AT Super Thunders.

 

[Sluggo]

Well...the Super Big Bertha is a PRO SERIES II kit, and not something a rocketry novice really needs to be building unless they have solid modeling skills.

Huh.?? The PSII kits go together just like most any other kit. There's nothing too complicated in a PSII kit that would be soo challenging that a beginner couldn't handle it. Easy peasey. If I'm wrong, go ahead and explain. Otherwise, don't be calling me out as a beginner who can't handle a PSII kit. Glue it and fly it. It does come with directions. Duh.

 

[Sluggo]

It should handle most any 29mm motor except maybe some hard hitting AT Super Thunders.

I've flown my Doorknob on a 29mm F20-4 without issue. I've also used an adapter and flown it on an F32-6 without issue. What are 'hard hitting AT Super Thunders.??'

 

[Ron Humphrey]

I really enjoyed building the SBB

 

[rharshberger]

I've flown my Doorknob on a 29mm F20-4 without issue. I've also used an adapter and flown it on an F32-6 without issue. What are 'hard hitting AT Super Thunders.??'

I was mistaken, there are no listed 29mm Super Thunders, the hardest hitting 29 from AT is probably the H268R. The H550ST is a 38mm motor.

 

[rharshberger]

Huh.?? The PSII kits go together just like most any other kit. There's nothing too complicated in a PSII kit that would be soo challenging that a beginner couldn't handle it. Easy peasey. If I'm wrong, go ahead and explain. Otherwise, don't be calling me out as a beginner who can't handle a PSII kit. Glue it and fly it. It does come with directions. Duh.

Got the wrong quote, I was replying to the OP's post and got the wrong one.

 

[artgsc]

One way to feel better about the fins on an Estes Super Big Bertha is to make their new Der Big Red Max your next build....

 

[DaHabes]

The biggest issue for me is the Estes airframe. It's way too thin. With the big fins it weathercocks badly in just about any wind. It zippered on it's first flight, and that's with having added a coupler just below the nose cone for added strength. The zipper stopped at the coupler. I repaired with another coupler and lengthened 3 inches. The second flight it weathercocked and was underpowered on an F23FJ (same engine as first flight). It did a parabolic dive into a creek - and then the ejection charge went off.

I'm on my second rebuild now. I had to design a custom 3D printed coupler since I already had couplers the entire length of the airframe that wasn't damaged. On this rebuild I'm going to add an Eggtimer Apogee altimeter in the nose cone for head end deployment at apogee with motor ejection backup. If it craters this time, I'll only rebuild as a custom build with LOC tubing and plywood fins for G's and H's. Estes shouldn't do rockets with 29mm MMTs at this point. They skimp on the design to make them fly-able on BP motors and, at least in the case of the SBB, it's a lousy design. Love the rocket, hate the design.

 

[DaHabes]

I was mistaken, there are no listed 29mm Super Thunders, the hardest hitting 29 from AT is probably the H268R. The H550ST is a 38mm motor.

That's no longer true. The AT G12ST is just around the corner, will take a SBB to 2000 feet, but REALLY weathercocks badly on a slow end-burner if there is any wind, like, more than 2MPH.

 

[CalebJ]

The biggest issue for me is the Estes airframe. It's way too thin. With the big fins it weathercocks badly in just about any wind. It zippered on it's first flight, and that's with having added a coupler just below the nose cone for added strength. The zipper stopped at the coupler. I repaired with another coupler and lengthened 3 inches. The second flight it weathercocked and was underpowered on an F23FJ (same engine as first flight). It did a parabolic dive into a creek - and then the ejection charge went off.

I'm on my second rebuild now. I had to design a custom 3D printed coupler since I already had couplers the entire length of the airframe that wasn't damaged. On this rebuild I'm going to add an Eggtimer Apogee altimeter in the nose cone for head end deployment at apogee with motor ejection backup. If it craters this time, I'll only rebuild as a custom build with LOC tubing and plywood fins for G's and H's. Estes shouldn't do rockets with 29mm MMTs at this point. They skimp on the design to make them fly-able on BP motors and, at least in the case of the SBB, it's a lousy design. Love the rocket, hate the design.

Interesting. I don't remember much weather cocking at all when I've flown mine.

 

[Sluggo]

The biggest issue for me is the Estes airframe. It's way too thin. With the big fins it weathercocks badly in just about any wind. It zippered on it's first flight, and that's with having added a coupler just below the nose cone for added strength. The zipper stopped at the coupler. I repaired with another coupler and lengthened 3 inches. The second flight it weathercocked and was underpowered on an F23FJ (same engine as first flight). It did a parabolic dive into a creek - and then the ejection charge went off.

I'm on my second rebuild now. I had to design a custom 3D printed coupler since I already had couplers the entire length of the airframe that wasn't damaged. On this rebuild I'm going to add an Eggtimer Apogee altimeter in the nose cone for head end deployment at apogee with motor ejection backup. If it craters this time, I'll only rebuild as a custom build with LOC tubing and plywood fins for G's and H's. Estes shouldn't do rockets with 29mm MMTs at this point. They skimp on the design to make them fly-able on BP motors and, at least in the case of the SBB, it's a lousy design. Love the rocket, hate the design.

I'm no scientist so bare with me. Wouldn't adding length or adding the coupler towards the nose cause the rocket to weathercock more.??