TLP Nike-Ajax Two-Stage Conversion

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dixontj93060

dixontj93060

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Those that know me from near or afar realize that I can tend to be pretty impulsive (especially with respect to rocketry transactions). One such transaction happened a week plus ago from this "sale tip": https://www.rocketryforum.com/showthread.php?131043-For-Those-that-like-The-Launch-Pad-kits. As it turns out I could have sourced the The Launch Pad (TLP) Nike-Ajax slightly cheaper at Hobbylinc, but that's OK, shipping was low so overall maybe a better deal net-net.

Anyway over the years have built three or four TLP kits. I am glad they continue to be in business putting out some interesting semi-scale rockets. Many builders get frustrated with TLP kits because they suggest (require) light building techniques to meet their published motor recommendations, recovery design, etc. These lightweight builds can tend to be fragile. I have built them this way, I have also built them very heavy and flown them on I motors. My point here is just because a kit is designed in a certain way, it doesn't mean you can't use your knowledge and experience to completely change the application/design. And with my Nike-Ajax I'm doing just that.

What am I doing? Well to answer that just take a gander at the rocket...

35d516_ac3ec1f4762eeb0f718dd830523699a0.jpg

Yeah, three motor cluster. That's cool, but... REALLY? This thing was originally a two-stage DoD platform. As a semi-scale rocket (at least in my mind) it has to be a two-stager! :gavel:

OK, now how do I get there?
 
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I've had one of these in the basement collection for years. I'll definitely be following along...
Didn't one of his plan packs have instructions on how to make this a two stage using gap staging? I'll dig around and see if I have that (I'm fairly certain I do). I think that was my (overly ambitious) plan.

Adrian
 
jd2cylman said:
I've had one of these in the basement collection for years. I'll definitely be following along...
Didn't one of his plan packs have instructions on how to make this a two stage using gap staging? I'll dig around and see if I have that (I'm fairly certain I do). I think that was my (overly ambitious) plan.

Adrian
Click to expand...

That Nike-Ajax is like 55" long iirc, the booster is about 24" or so probably a bit hard to gap stage that one reliably. The Nike Hercules Plan Pak uses a interesting electric ignition system to ignite the upper stage.
 
I need to repair mine (have not flown it in years). The upper tube strength and the transition section are the weak points of the design (and the failure points with multiple flights). As it get heavier, getting a big enough chute into the narrow upper section can be a problem.
 
terryg said:
I need to repair mine (have not flown it in years). The upper tube strength and the transition section are the weak points of the design (and the failure points with multiple flights). As it get heavier, getting a big enough chute into the narrow upper section can be a problem.
Click to expand...

Yep, agree with this. I'll post my approach to address some of this later today.
 
At a disadvantage in this post as I left my computer at work. So instead of going into some of the more critical areas like the interstage design and electronics/stage sequencing, I'll stick with some of the mainstream build steps. First step (well my first step, not the instructions first step), cut out all intricate parts typical of a TLP kit.

ImageUploadedByRocketry Forum1452298192.450752.jpg

Problem is, that's not nearly all of them as there are a number of conduits and other axial details.

ImageUploadedByRocketry Forum1452298295.648107.jpg

Plan is to work on the first group and the structural integrity of the airframe and leave the second group until final assembly.
 
You may note above the first deviation from a normal TLP build. The Nike fins on the right have already been shaped and laminated with one layer of 2.7oz fiberglass. In addition those larger fins on the booster will have some impact risk associated with them given their position and what will normally be flights with three Aerotech 24/40 reload motors so I decided to add thru-the-wall tabs and conveniently extend them down into the V-channel of the three motor cluster to provide an extra secure mount (this will be more obvious when I'm able to post the Rocksim file). You might note the TTW tabs are offset (to aft in my build). That is done as that really was the only available fit given the dimensions of the balsa stock shipped by TLP with the kit (tabs needed to be just over a half inch deep and were made 2.625" long to fit CR-to-CR on the motor mount).

As terryg mentioned the upper body or sustainer in this case is a fragile part of the build. They are the various triangular balsa pieces in the first picture. They will also have fiberglass lamination. Since the fins aren't TTW I will just do tip-to-tip or veil application after surface mounting the fins.
 
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Most of the build is with 30 min. Bob Smith type epoxy. This is most a matter of convenience as I have some remnants in a couple bottle sets I'm trying to consume. Saying that, I'm attempting to use minimal epoxy/small fillets and go heavy with colloidal silica to lighten it up as much as practical. Quick shot of booster motor mount below. A deviation here. To match the TTW fin tabs, I moved the MMT aft about 3/4" versus the instructions. You might recognize that TLP kits often move the mount forward to shift the CG forward. Moving it back is not bad in this case as weight in the design will be added forward with fin lamination on the sustainer, electronics install and a beefier interstage coupler assembly.

ImageUploadedByRocketry Forum1452301015.392349.jpg

Had a couple of nights in a hotel earlier in the week and was able to do initial assembly as below.

ImageUploadedByRocketry Forum1452301109.667031.jpg
 
Before traveling this week I was able to get a couple orders off last weekend for parts that will be needed when I transition to the "internals" of this build. First a grouping from Balsa Machining.

ImageUploadedByRocketry Forum1452301462.371587.jpg

And then maybe the only vendor to have a Perfectflite timer in the US, Chris' Rocket Supply.

ImageUploadedByRocketry Forum1452301533.196892.jpg

More on all these parts later.
 
dixontj93060 said:
Most of the build is with 30 min. Bob Smith type epoxy. This is most a matter of convenience as I have some remnants in a couple bottle sets I'm trying to consume. Saying that, I'm attempting to use minimal epoxy/small fillets and go heavy with colloidal silica to lighten it up as much as practical. Quick shot of booster motor mount below. A deviation here. To match the TTW fin tabs, I moved the MMT aft about 3/4" versus the instructions. You might recognize that TLP kits often move the mount forward to shift the CG forward. Moving it back is not bad in this case as weight in the design will be added forward with fin lamination on the sustainer, electronics install and a beefier interstage coupler assembly.

View attachment 279395

Had a couple of nights in a hotel earlier in the week and was able to do initial assembly as below.

View attachment 279396
Click to expand...

Looking good so far, definitely a good idea to ttw the fins and a light glassing. :)
 
Had a little bit of time to work on the interstage coupler today (would have had more time but started work on my LOC King Viper III). Didn't actually do any assembly but instead did a lot of sanding, fitting, adjustment, etc. to get the TLP and Balsa Machining parts to work together. Of course, this area of the design/build is a bit tricky so I did a scale drawing of all the piece parts before ordering last week and it is my guide for cutting and assembly tomorrow.

Interstage Coupler.jpg
 
Are you planning to port the interstage? Whats the distance between upper and lower stage motors? How is the parachute deployment for the booster initiated? Sorry lots of questions and I am curious about how you are handling them as I eventually plan to build this kit to be a two stager.

Nevermind the porting question or distance as you are initiating the airstart via timer.
 
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rharshberger said:
Are you planning to port the interstage? Whats the distance between upper and lower stage motors? How is the parachute deployment for the booster initiated? Sorry lots of questions and I am curious about how you are handling them as I eventually plan to build this kit to be a two stager.

Nevermind the porting question or distance as you are initiating the airstart via timer.
Click to expand...

Booster and sustainer will both be motor deploy. Think of the interstage coupler as simply the nosecone for the booster.
 
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dixontj93060 said:
Booster and sustainer will both be motor deploy. Think of the interstate coupler as simply the nosecone for the booster.
Click to expand...

Thanks, if you are using three 24/40 motors I recommend setting them to different delay lengths or only using one motor for ejection and plugging the others. My SA-3 Goa which I scratch built had issues with over pressuring the tubing when dual ejection charges went off at the same time from the cluster motors, another more experienced member here told me that I was full of ..it and that Estes motors couldn't rupture the stuffer tube (BT-50H), but they can and did as I discovered repairing the damage, and AT motors use larger charges than Estes motors though you don't have a stuffer tube here.
 
rharshberger said:
Thanks, if you are using three 24/40 motors I recommend setting them to different delay lengths or only using one motor for ejection and plugging the others. My SA-3 Goa which I scratch built had issues with over pressuring the tubing when dual ejection charges went off at the same time from the cluster motors, another more experienced member here told me that I was full of ..it and that Estes motors couldn't rupture the stuffer tube (BT-50H), but they can and did as I discovered repairing the damage, and AT motors use larger charges than Estes motors though you don't have a stuffer tube here.
Click to expand...

Yes, will only set up one for ejection, other two will be plugged.
 
OK, spent a bit of time correcting the Rocksim file I downloaded from EMRR (closest I could find, but many dimensions were off plus had to add my interstage components).

tlp_nike_ajax_staged_v3.jpg
 

Attachments

  • tlp_nike_ajax_staged_v3.rkt
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Tim, have you seen the Tripoli NC project? Already built 1/2 scale. It's even been on local news. They are currently working on the full scale. I apologize, I don't have any links.
 
Big fan of this rocket and I've been really close multiple times to trying this kit out. Keep up the nice work!
 
jimzcatz said:
Tim, have you seen the Tripoli NC project? Already built 1/2 scale. It's even been on local news. They are currently working on the full scale. I apologize, I don't have any links.
Click to expand...

Jim, would love to see it if you find any info... /Tim
 
dixontj93060 said:
Those that know me from near or afar realize that I can tend to be pretty impulsive (especially with respect to rocketry transactions). One such transaction happened a week plus ago from this "sale tip": https://www.rocketryforum.com/showthread.php?131043-For-Those-that-like-The-Launch-Pad-kits. As it turns out I could have sourced the The Launch Pad (TLP) Nike-Ajax slightly cheaper at Hobbylinc, but that's OK, shipping was low so overall maybe a better deal net-net.

Anyway over the years have built three or four TLP kits. I am glad they continue to be in business putting out some interesting semi-scale rockets. Many builders get frustrated with TLP kits because they suggest (require) light building techniques to meet their published motor recommendations, recovery design, etc. These lightweight builds can tend to be fragile. I have built them this way, I have also built them very heavy and flown them on I motors. My point here is just because a kit is designed in a certain way, it doesn't mean you can't use your knowledge and experience to completely change the application/design. And with my Nike-Ajax I'm doing just that.

What am I doing? Well to answer that just take a gander at the rocket...

View attachment 279360

Yeah, three motor cluster. That's cool, but... REALLY? This thing was originally a two-stage DoD platform. As a semi-scale rocket (at least in my mind) it has to be a two-stager! :gavel:

OK, now how do I get there?
Click to expand...

Hmm...I wonder who you're referring to? :wink:

Regarding missing out on a lower price, that's no big deal...prices fluctuate all the time and it could've gone up more if you didn't buy it when you did. Besides, sometimes it's best to buy what you want at the time rather than buy at a lower price thinking you'll want it later. A few bucks is nothing compared to all the other things we buy and spend on with this hobby.

I generally try to tell beginners (ex. haven't built and launched more than a few starter rockets) to stick with the instructions since following the instructions is usually the best way to guarantee success in those cases (except those few occasions when instructions are wrong) and when dealing with a lightweight rocket that some would say is tricky to launch (I think so).

However I think it's a really cool thing to build up from the TLP designs once you have more experience and you're definitely up to the task (quite and understatement there). I'm considering the same for a few of the TLPs I have and I've actually already gotten the Nike Ajax when it was sale from Hobbylinc and was earlier considering modifying it into a 2-stager like you. :)

BTW - If I may ask, what is your opinion of the TLP kits in stock form?
 
OK, doesn't look like much yet, but main components are there and they all fit. Well fit to the first order. I have some sanding to do in a few spots to perfect the fit I want, but 90% there. Surprisingly the balsa struts also fit fairly well which surprises me as I was sure I'd screw up the center bits in the interstage somehow.

ImageUploadedByRocketry Forum1452472535.879586.jpg
 
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My favorite all time rocket, Tim!

Nice pick. One of our club member does this, very close to yours. He uses 3 BP motors in booster and the Perfectflite timer to light a BP motor in sustainer.
Works very well and always exciting, crowd pleasing flights.
Yours will be too!
 
blackjack2564 said:
My favorite all time rocket, Tim!

Nice pick. One of our club member does this, very close to yours. He uses 3 BP motors in booster and the Perfectflite timer to light a BP motor in sustainer.
Works very well and always exciting, crowd pleasing flights.
Yours will be too!
Click to expand...

Thanks Jim. I'll be opting for three AP motors using the trusty Aerotech 24-40 cases for the booster and keeping it "open ended" for the sustainer to see if its up to long-burn options from Cesaroni after a shakedown flight or two.
 
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Cool project! I like the setup, and yes, it HAS TO BE built as a 2 stager!:).

I built a 2.5" to 1.6" Nike-Tomahawk a few years back....used a Perfectflite minitimer for sustainer ignition as well.

Keep up the good work, and I'll be watching for that King Viper III at MWP14!

-Eric-
 
I have flown my stock one many (10ish) times and over time the three BP ejection charges will do in the thin craft tubing above the motor mount, so a bit of reinforcement there is warranted. You need a hefty ejection charge to deploy the tightly packed mylar chutes. Good chute packing and talc are required for the stock version to get both chutes to fully deploy. Any interstage damage is easily fixed with some CA. As for TLP kits there are lovers and there are haters. For big mods it will take some experience, built stock they are fine for anyone wanting more of a builder's kit than the usual fare. Do not use the "swamp mud" nose weight - replace it with plasticine or properly glued in shot/bbs. Attaching the nose cone per the instructions with a single piece of string is a bit weird as is the oblong cut on the chutes. I haven't seen this kit two staged but I have seen two stage scratchers fly real nice. With some cool after market decals and getting all three motors to light you will surely be a TLP LOVER!
 
Daddyisabar said:
I have flown my stock one many (10ish) times and over time the three BP ejection charges will do in the thin craft tubing above the motor mount, so a bit of reinforcement there is warranted. You need a hefty ejection charge to deploy the tightly packed mylar chutes. Good chute packing and talc are required for the stock version to get both chutes to fully deploy. Any interstage damage is easily fixed with some CA. As for TLP kits there are lovers and there are haters. For big mods it will take some experience, built stock they are fine for anyone wanting more of a builder's kit than the usual fare. Do not use the "swamp mud" nose weight - replace it with plasticine or properly glued in shot/bbs. Attaching the nose cone per the instructions with a single piece of string is a bit weird as is the oblong cut on the chutes. I haven't seen this kit two staged but I have seen two stage scratchers fly real nice. With some cool after market decals and getting all three motors to light you will surely be a TLP LOVER!
Click to expand...

Good point on the protection of the booster charge. I'll add some protection there. There will be no mylar chutes in this design. I am going with a couple of Top Flight thin-mil chutes, one for booster, and one for sustainer. I've looked at the scale drawings and there really aren't too many decals on working missiles. I do intend to try some painting/highlight slight-of-hand to enhance the fin shape on all 11 fins (we'll see how that turns out :confused:).
 

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