Estes Sentinel Upscale

[Dseter]

I actually built this 2.56 diameter upscale years ago based on the Estes Sentinel I already had and launched it many times on G's. It got beat up over the years so last week I sanded it down a bit, gave it a new paint job and just finished applying vinyl decals from Mark at Stickershock. Hope to let her rip on an F-50 this weekend, yahoo!

 

[gdjsky01]

Excellent work!
:handshake:

- jeff

 

[El Cheapo]

Sweet, my favorite sport-scale missile. I've planned on doing one for some time now, along with many other upscale that haven't yet made it to fruition. I'm sure you can relate.

 

[maricopasem]

Love that rocket, and yours are exceptional!

 

[dr wogz]

Super kudos to your work! Nicely done! And cut vinyl is totally the way to go! This too, is one of my favorites!

Could we ask you to post some details? Fin dims mainly? So we might also make a fabulous upscale..
I assume that's a 'Binder Desing' long nose cone..

 

[Dseter]

Excellent work!
:handshake:

- jeff

Cool, thanks Jeff!

 

[Dseter]

Super kudos to your work! Nicely done! And cut vinyl is totally the way to go! This too, is one of my favorites!

Could we ask you to post some details? Fin dims mainly? So we might also make a fabulous upscale..
I assume that's a 'Binder Desing' long nose cone..

Yeah, thanks guys for the positive comments and hats off to Mark at Stickershock- Give me a little time this weekend and I'll edit this post with some details on the parts and process as I remember it anyway. I'm making a same upscale sized Citation Patriot and Nike-X now if i can just find a bigger Nike-X nose cone.

 

[sodmeister]

Nice work.....I REALLY LIKE THE LOOKS OF THAT UPSCALE !!

Paul T

 

[cjp]

Yeah, thanks guys for the positive comments and hats off to Mark at Stickershock- Give me a little time this weekend and I'll edit this post with some details on the parts and process as I remember it anyway. I'm making a same upscale sized Citation Patriot and Nike-X now if i can just find a bigger Nike-X nose cone.

The Nike X is one that I would like to upscale,can you post those details to?

 

[qquake2k]

Woot!

 

[stickershock23]

Now that is just cool!

 

[emckee]

I actually built this 2.56 diameter upscale years ago based on the Estes Sentinel I already had and launched it many times on G's. It got beat up over the years so last week I sanded it down a bit, gave it a new paint job and just finished applying vinyl decals from Mark at Stickershock. Hope to let her rip on an F-50 this weekend, yahoo!

Beautiful rockets! This was one of my favorite kits as a kid, "back in the day" and I've recently been pondering an up-scale, so let me echo the request for dimensions (don't have mine any more). Fins particularly, but also BT length (wondering if it was just an 18" tube) and nose cone length. I figure the internals I can work out on my own (hmmm, cluster? Maybe HPR 38mm?)

Thanks!

 

[dr wogz]

I have the fin sheet, from Jim Z's site, jsut need to "input" them into the CAD device.

And, yes, I check teh BT, and it's an 18" lenth.

The nosecone si a strange one though. Probabaly the only long nosecone Estes ever put out, and only for one rocket. definitely strange..

 

[Dseter]

Beautiful rockets! This was one of my favorite kits as a kid, "back in the day" and I've recently been pondering an up-scale, so let me echo the request for dimensions (don't have mine any more). Fins particularly, but also BT length (wondering if it was just an 18" tube) and nose cone length. I figure the internals I can work out on my own (hmmm, cluster? Maybe HPR 38mm?)

Thanks!

Yes, apologies for the delay, life got in the way of all my fun here- the upscale BT is 2.5" Diameter and 30 inches length. The nose cone is 13 inches long from point to the beginning of the shoulder and the shoulder is 2 3/4 inches long. I think the cone is PML ( Like the Callisto) but the tube is more likely a LOC Precision tube but I really don't remember. I'll try to get some measurements on the fins by the end of this weekend, thanks for the interest!

 

[mwtoelle]

The nosecone si a strange one though. Probabaly the only long nosecone Estes ever put out, and only for one rocket. definitely strange..

The Sentinel used a PNC-60RL nose cone. The Vagabond is the only current Estes kit that uses that nose cone.

 

[hornet driver]

OK, That falls into the extremely cool catagory---VERY NICE INDEED!!!

 

[AZ_Ron]

Just found this thread while searching for "Estes Sentinel" great looking upscale! I'm planning on doing one in 4". I have the decals from Mark at Stickershock. He made them for me a few years ago, but I've been on Hiatus.
I'd built a 5.5" version a LONG time ago, I think it was 1998. Here's a pic of it at Springfest, back when the launches were at El Dorado, instead of Jean, NV.
It met a sad end on it's first and only flight. Very small, simple, stupid mistake on my part. Oh well, live and learn!

Ron

 

[blackbrandt]

It met a sad end on it's first and only flight. Very small, simple, stupid mistake on my part. Oh well, live and learn!

Ron

Quick-Link?

:rofl:

If so, troj has some competition...

 

[AZ_Ron]

LOL...Nope, that's what mode of failure I've not done myself. We have a local guy who's had crashes due to open qwik-links several times though!

I did something new (at the time) on this when I built it. I went with a zipperless construction, single deployment with the chute being
pulled out from the payload bay, instead of being blown out with the nosecone.
I used a 50' kevlar leash that I'd used before with a Rocketman chute. I also attached the chute in the same location I normally did, about 5' from
the nosecone on the leash. At deployment, it was picture perfect, except for the part where the chute was supposed to deploy.
The harness stretched fully out, but because of where I'd attached the chute, the chute was still just inside the payload section.
about 2' of the shroud lines were out, but not enough to pull the chute the rest of the way out. It landed hard. We walked out to it, and
just pulled the chute right out. It wasn't tight at all. Took us a little bit to figure out what happened. Had I flipped the harness around to where
the chute was attached 5' from the booster section, it would have been one of my best flights ever. Devil's in the details!

R

 

[SMR]

I did something new (at the time) on this when I built it. I went with a zipperless construction, single deployment with the chute being pulled out from the payload bay, instead of being blown out with the nosecone. I used a 50' kevlar leash that I'd used before with a Rocketman chute. I also attached the chute in the same location I normally did, about 5' from the nosecone on the leash. At deployment, it was picture perfect, except for the part where the chute was supposed to deploy. The harness stretched fully out, but because of where I'd attached the chute, the chute was still just inside the payload section. about 2' of the shroud lines were out, but not enough to pull the chute the rest of the way out. It landed hard. We walked out to it, and just pulled the chute right out. It wasn't tight at all. Took us a little bit to figure out what happened. Had I flipped the harness around to where the chute was attached 5' from the booster section, it would have been one of my best flights ever. Devil's in the details!

Ouch. As I was reading that, I was picturing the exact same scenario played out last fall in a local L2 certification attempt. The flyer had a short rocket with a heavy nose cone, and wanted the nose cone to land first, so he switched the shock cord around to give the nose cone the longer length of shock cord, which left a short length between the rocket body and the parachute attachment point. The motor ejection managed to blow the nose cone and its really long shock cord clear, but left a substantial part of the parachute in the payload bay. No matter how hard the nose pulled on the shock cord during its long fall from apogee, there remained slack in the shroud lines and the parachute stayed put. End result was a cracked fin. Bummer.

P.S. Nice looking rocket, Dseter. Sorry for the thread hijack.

 

[AZ_Ron]

Not to continue the hijack, but here's a video of the flight. Please keep in mind this was back in I believe '98 or '99, recorded on videotape.
https://youtu.be/Mw7DAEQSREs

Ron

 

[Launch Lug]

So glad I found this thread. The Sentinel was the one rocket kit that my older brother built when we were younger that him and his friend use to launch. I never got into them as a kid myself but I remember seeing this rocket sitting on his dresser every time I walked into his room. I love the looks of it and since I found this thread a couple of days ago I am determined to do a build from scratch to specs. Reading through this thread it was mentioned that the Vagabond uses the same NC as this kit did (at least shape and size) so I ran out to Hobby Lobby with my 40% off and bought a kit. I got real nervous after I bought the kit and then started looking at the Rocksim file only to see that the file shows the kit as a BT-55 and not a BT-60, I thought I had just wasted my money and immediately lost interest. However after searching and reading an old thread on the Sentinel it was clear that the file is wrong and it is indeed a BT-60... just going to steal the NC, the 18" section of tube and the parachute out of the kit and build everything else. Happy once again and eager to build!

 

[emckee]

For those of you who have done upscales on the Sentinel design, what have you used for fin material, and what thickness? Those aft fins have a large surface area, and I suspect would be prone to flutter under the wrong conditions, so I'd love to hear what you used and whether you've cracked your fillets, lost a fin, etc

Thanks!
Erik

 

[Event Horizon]

Reviving this thread from days gone by because I'm working on a parts list to build an upscale version. I think the nose cone is available from erockets. It's a plastic cone made by Aerotech part number 11261 and is a 5.1 ogive, same as the Estes Sentinel kit.
Can anyone help with with compatibility questions as I'm new to the bigger rocket classes.
Nose cone 11261 Aerotech Nose Cone - 2.6 in 5/1 Ogive 11261
BTH-80 body tube (four slots for fins) Aerotech Body Tube - 2.6 in Slot / 4-Fin 24.00 in 12623
The reason I chose this tube is I'm not sure if I'll ever fly it so the launch lug slot isn't necessary. If I change my mind I can always add the launch lug
BTH-80 body tube Aerotech Body Tube - 2.6 in Unslotted 19 in 12619
Is there a better tube to use that is longer and won't need to be coupled and cut to upscale length? and I hate filling spiral grooves.....
Coupler Semroc Couplers CPL-80-4"(1pk) SEM-CPL-80-4" *
is there a better coupler? Would a one inch long coupler assemble easier?
Motor mount Semroc Engine Mount Kit #9 to BT-80 SEM-EM-9-80P *
Will these parts fit each other??
I believe erockets can laser cut fins with tabs, is there a another source in case they cannot?
Stickershock has the decals.

Thanks guys

 

[dmo]

Is there a better tube to use that is longer and won't need to be coupled and cut to upscale length?

One option is www.balsamachining.com There tube ST1-11 is a BT80H 34" long with 4, 1/8" slots. ST1-15 is similar with 3/16" slots.
You can find them under "Kits & Bldg Supplies"->"Misc"

Not sure, but I think LOC will do custom tube slots, and they have 30" long 2.56" paper tubes. They may even cut it to length for you.

If you are willing/able to cut the slots yourself there are lots more options, including FW fiberglass which wouldn't require filling spirals.

 

[Event Horizon]

OK, I have ordered a bunch of the parts needed to scratch build a couple 2.6 inch diameter airframe 44 inches tall Sentinels. My question, which defies any logic on my part is, If the original size Sentinel uses an 18 inch parachute, would the upscale version using a 2.6 inch diameter airframe need a 30" diameter parachute? The upscale is 63% greater than the original Sentinel. 18" x 1.63 equals 29.34 inches so 30" parachute?? I suppose I really need to know how much the upscale Sentinel weighs before I can determine the parachute size. Any offers of advice? Any rules of thumb for parachute sizing?
Thanks again

 

[K'Tesh]

I would recommend trying to find similar sized rockets that fly on similar motor choices as what you have, then base your parachute choices on that. To make things even better, go with a larger parachute, but use a JLCR to reef the chute (and set to deploy at an altitude you're comfortable with) to insure that you'll be able to recover your rocket for your available field size.

 

[Event Horizon]

OK, after a bit of research I think I understand JLCR technology.

I kind of like that idea, and the oversized parachute makes sense especially when that parachute can be deployed at a lower altitude to lessen the down range recovery distance.



Thanks for the help.

 

[Event Horizon]

OK, I have ordered a bunch of the parts needed to scratch build a couple 2.6 inch diameter airframe 44 inches tall Sentinels. My question, which defies any logic on my part is, If the original size Sentinel uses an 18 inch parachute, would the upscale version using a 2.6 inch diameter airframe need a 30" diameter parachute? The upscale is 63% greater than the original Sentinel. 18" x 1.63 equals 29.34 inches so 30" parachute?? I suppose I really need to know how much the upscale Sentinel weighs before I can determine the parachute size. Any offers of advice? Any rules of thumb for parachute sizing?
Thanks again

I'm back to let everyone know that's following this thread, I've started a new thread titled "Sentinel Upscale 2019" in the Scratch Built section.