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  #1  
Old 11-16-2007, 10:25 AM
Rocket Doctor Rocket Doctor is offline
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Default Building the 1350 Interceptor

I'm starting a new thread here dealing with the 1350 Interceptor only, we were getting off track with the A ? for the Rocket Doctor thread.

So, if you have purchased, plan to purchase or have already built the 1350, please post your comments here.

We can all come up with ideas on building, finishing and slying this rocket.

I have mentioned this before, the shock cord is much too short by at least 11 inches, be aware of this.
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Old 11-16-2007, 10:39 AM
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Thanks RD...this is a good idea.

Just wanted to put my 2 cents worth concerning the wing braces. I can understand why they were added since those areas are the weakest points on the wings. The braces do tend to distract from the original Interceptor. I don't know if I mentioned this before or someone else has, but I think I'm going to use a card stock laminate on the wings. Two reasons...

1. Added strength to the joint without using the braces.
2. There's a whole lot of balsa there. The card stock won't need to be filled.

As for the shock cord. I think we've all got use to replacing whatever comes in the Estes kits. RD is right. We need to complain to Estes so they know we aren't happy. Then, go ahead and replace it with whatever you want to use. Let's not forget that the original function of the shock cord was to keep everything together. Butcher string works just as well as long as it's long enough not to break from the force of ejection. Personnally, I use the elastic and I use a minimum of two times the body length. Keep in mind, some damage we blame on short shock cords could just as easily be early deployments and the momentum of the rocket continues and hits the nose cone.

Okay....maybe 5 cents worth of letters and a penny worth of thought...
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Old 11-16-2007, 10:55 AM
Rocket Doctor Rocket Doctor is offline
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Don

Thanks for the input, this is what we need, comparing notes, and, making suggestions.

RD
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Old 11-16-2007, 11:10 AM
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I'll have to just watch and listen.

Although I just got two big Interceptors in...I'm kinda busy right now.
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Old 11-16-2007, 11:30 AM
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I totally agree that the shock cords in Estes kits are TOTALLY inadequate.
I personally use a 3x BT length rule for these and almost ALWAYS use a kevlar leader attached to the forward portion of the engine mount or ejection baffle with the shock cord tied to that. Where the kevlar crosses the forward opening of the body tube, I use an anti-zippering device.

I would have liked Estes to use NON-braced basswood or plywood for the fins instead of the braced balsa. If they want it to handle mid-power levels they should use mid-power materials. Estes is the only company that is hell-bent on only reccommending only THEIR engines for THEIR kits, yet they offer something constucted of components that will not fly decently on an Estes D or E-anything but are fine for an Aerotech RMS 24 F39T. At 10.5+ ounces this thing will not fly decently on an E9-ANYTHING w/o an 8ft launch rod. A D12 will work, but I suspect the flight will be dismally low, just like the old Maxi-Brutes on a D12-3.
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Old 11-16-2007, 12:37 PM
Rocket Doctor Rocket Doctor is offline
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It was probably the cost factor, a strip of balsa is cheaper than a whole fin of basewood.
They don't think about individual kits costs, it's the whole production run, and, for a kit with a suggested reatil of $49.99, you want your money's forth.

I brought up about the shock cord, mainly, if I spent 50 bucks on the basic kit, then the finishing supplie, built the kit and had is destroyed because of a shcok cord, I certainly woundn't be happy.

So, we gather our thought here, and, they will be passed along once again, I hope that they have their listening ears on, as Judge Judy would say.......

Keep the comments and update coming.
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Old 11-16-2007, 12:47 PM
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I can understand that sort of strategy for $8.49 beginner kits at Wal Mart, but NOT for kits built by REAL model builders that have been doing it for years.
When a kit has a retail of around $50.00, I do NOT expect it to have ANY inferior materials.
They wisely decided to include a Nylon Chute which must have cost MUCH more than a plastic chute. Supplying the kit with a PROPER length of shock cord should be considered a quality MINIMUM, as I think should be the basswood fins.
Small things like this will continue to cause me to be ticked off at Estes.
They have really went downhill since the early 90's, and while I see that they are trying to make a comeback, little things like this are BIG glitches in this as I see it.
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ALL systems are GO for MAYHEM, CHAOS, and HAVOC !
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Old 11-16-2007, 01:30 PM
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I am still not convinced that these braces are necessary. I have several models with large, surface mounted balsa fins and have not had any problems.

Rocket Dr: Are you aware of any test failures, or other issues during development that caused these braces to be added?

I am not trying to be argumentative, but I am just trying to get to the root of why there are part of the design.

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Old 11-16-2007, 02:31 PM
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Quote:
Originally Posted by barone
...Just wanted to put my 2 cents worth concerning the wing braces. I can understand why they were added since those areas are the weakest points on the wings...


Could someone re-post the existing photos of the prototype 1350 here to refresh our memories about these braces?

If these braces are positioned like "wing fences" on 50's and 60's era supersonic fighters, then we're talking about chord-wise braces instead of span-wise, right?

Has anyone thought about using some very thin carbon-fibre strips in place of the cardstock, or even the balsa? Some of this material is very thin in comparison, but would provide far more reinforcement, and when primed over would nearly disappear from view.
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Old 11-16-2007, 03:13 PM
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Quote:
Originally Posted by excelsior_rocketry
I am still not convinced that these braces are necessary. I have several models with large, surface mounted balsa fins and have not had any problems.

Rocket Dr: Are you aware of any test failures, or other issues during development that caused these braces to be added?

I am not trying to be argumentative, but I am just trying to get to the root of why there are part of the design.

Phred

Phred,

I think maybe they were thinking that the added weight of the pods at the end of the wings might be the problem. That's just my thought about what they were thinking. But, who really knows what they were thinking. What were they thinking?
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