Estes Exo-Skell # 2163 Restore with modifications.

[Back_at_it]

When the Exo-Skell first came out I picked one up immediately. I thought the idea of the alien lander was awesome and would make things interesting at least until I got bored with it or got tired of chasing down two different pieces. Unfortunately I did not realize how quickly that would happen.

I remember flying on the recommended C6–3 and immediately thinking something was wrong. It was a calm day but the rocket immediately turned on its side once it left the rod and flew near horizontal. The ejection charge popped just feet before it hit the ground. I got lucky and nothing was broken.

I had some C5–3 motors left in my range box so I tried one of those. The flight was better but still incredibly underpowered and unstable. I was lucky if I got 200 feet on that flight. At least this time it came back under two parachutes as Estes intended. That rocket never flew again while I owned it and I eventually gave it away to one of the neighbors kids with the agreement that he would never try to fly it.

Fast forward 10+ yrs. I bought a forgotten collection and there was an Exo-Skell in the box. One of the fins was broken and the main body tube was full of dirt. It looked almost like it took a core sample.

Following the Ninja Upscale build, I decided that I wanted to do something different. I looked down and there was the Exo-Skell with its bulbous head sticking out of the top of the box. I figured why not. I just have to figure out how to fix the under power issue as well as the lack of room for recovery gear. Don't worry I have a plan

Here is what I started with. I was able to pull apart the remainder of the rocket so I had all of the necessary pieces. The fin can already had one broken fin and knowing that I couldn't put anything more than an 18mm motor in it, the remaining fins were cut from the can and saved.




After digging through the parts boxes I've come up with the following. A piece of BT55 heavy wall for the upper tube as well as the lower tube that will serve as the attachment point for the fins.. The lower tube will also receive a full-length coupler to add additional rigidity. A BT50 heavy wall tube will be used for the motor tube / lower body tube.

To put this together I'll be using a combination of cardboard and plywood centering rings and adding a Qualman rockets baffle to eliminate the need for recovery wadding.



I started with the motor mount. This is simply a BT20/50 centering ring used as a motor block. The location was measured and the centering ring was inserted far enough up that I can run the longer 24mm "E" motors from Estes.



Next I moved to the lower tube which will be the attachment point for the fins. This tube will receive a full-length coupler for added strength. Since I am going to be using epoxy to connect the plastic fins I figured a little extra rigidity would not hurt.

Here we have the lower tube, the coupler and a couple of centering rings. The centering rings have been sanded on the inside and outside diameter so that they fit inside the coupler.




I have been asked a couple of times how I do full-length couplers. A lot of people say that the only way you can do this is using epoxy. Here is how I do it using regular old TBII. Simply coat the inside and outside of the tube and coupler then slide them together. you do have to be quick about it and not stop, but this is only ever been an issue for me one time when trying to do a full 18 inch long tube.

Here is the assembled lower tube with the coupler installed. Next it's time to install the centering rings.



That is as far as I got last night

Thanks for following along. I'll have more on this tomorrow..

 

[BABAR]

Here’s how I did mine. The C5-3 and the QJet 18 mm Ds weren’t around, so I had to upsize to 24 mm, which worked great but too a bit of doing.

I found a black sharpie and acetone worked to age the fins and the legs well.

something I might do different is buy thin mill chutes, the storage space for laundry on this bird is really tight.

best wishes,

 

[Back_at_it]

Here’s how I did mine. The C5-3 and the QJet 18 mm Ds weren’t around, so I had to upsize to 24 mm, which worked great but too a bit of doing.

I found a black sharpie and acetone worked to age the fins and the legs well.

something I might do different is buy thin mill chutes, the storage space for laundry on this bird is really tight.

best wishes,

Thank you. I'm increasing the size of the upper tube to allow additional room for the recovery gear. I figure with the increased weight and size, both the Sustainer and pod will need an 18in chute to land successfully so the increased space will come in handy.

 

[BABAR]

Thank you. I'm increasing the size of the upper tube to allow additional room for the recovery gear. I figure with the increased weight and size, both the Sustainer and pod will need an 18in chute to land successfully so the increased space will come in handy.

actually that is a GREAT idea, only downside is that wrap won’t cover it so you will need to wing it a bit for some additional appropriate decor. Or have StickerShock do a custom lengthened wrap.

if you add length, keep track of your weight. I think @Antares JS mentioned a different rocket, the Outlander, that was underpowered on a C6 and did NOT do well on the C5 either, see post 11

https://www.rocketryforum.com/threa...engine-performance-chart.164968/#post-2109890
The plastic mount on the Exoskell does not lend itself to upsizing to 24 mm easily (my inelegant solution was basicallly to add a 24 mm mount built on similar to a booster stage with its own fins. It worked great, but some may not like the optics.

make sure you adjust the position of the ring that holds the legs folded on boost..

lengthening the rocket will also increase your stability, usually a good thing, may increase tendency to weathercock a bit.


maybe someone will chime in here, what I DON’T Know is whether the QJet D Casings get hotter than the Estes cardboard. That MIGHT potentially melt the plastic motor mount, I don’t recall if there is cardboard tubing inside or not.

 

[Back_at_it]

actually that is a GREAT idea, only downside is that wrap won’t cover it so you will need to wing it a bit for some additional appropriate decor. Or have StickerShock do a custom lengthened wrap.

if you add length, keep track of your weight. I think @Antares JS mentioned a different rocket, the Outlander, that was underpowered on a C6 and did NOT do well on the C5 either, see post 11

https://www.rocketryforum.com/threa...engine-performance-chart.164968/#post-2109890
The plastic mount on the Exoskell does not lend itself to upsizing to 24 mm easily (my inelegant solution was basicallly to add a 24 mm mount built on similar to a booster stage with its own fins. It worked great, but some may not like the optics.

make sure you adjust the position of the ring that holds the legs folded on boost..

lengthening the rocket will also increase your stability, usually a good thing, may increase tendency to weathercock a bit.


maybe someone will chime in here, what I DON’T Know is whether the QJet D Casings get hotter than the Estes cardboard. That MIGHT potentially melt the plastic motor mount, I don’t recall if there is cardboard tubing inside or not.

I have the body wrap covered. It's not exact but I found something called Alien Skin that I'm planning to use.

I'm not sure what a stock one weights as I forgot to weight this one before I tore it apart. I did remember to measure the CG which is so far forward I could add a cluster of "D" motors and still be safe.

Agreed on using the stock plastic fin can. No way to get anything bigger than 18mm in there. The entire fin can is being replaced. The fins have been cut off and will be attached to the lower BT55 body tube.

I took measurements of the location of the ring for the legs. I'll also be testing and do mockup before gluing anything in place.

The Q-Jets get substantially hotter than the Estes motors. I would expect some melting if you used one in this rocket but I can't confirm that. I've seen melting in plastic fin units of other rockets from Estes B and C motors.

 

[BABAR]

I have the body wrap covered. It's not exact but I found something called Alien Skin that I'm planning to use.

I'm not sure what a stock one weights as I forgot to weight this one before I tore it apart. I did remember to measure the CG which is so far forward I could add a cluster of "D" motors and still be safe.

Agreed on using the stock plastic fin can. No way to get anything bigger than 18mm in there. The entire fin can is being replaced. The fins have been cut off and will be attached to the lower BT55 body tube.

I took measurements of the location of the ring for the legs. I'll also be testing and do mockup before gluing anything in place.

The Q-Jets get substantially hotter than the Estes motors. I would expect some melting if you used one in this rocket but I can't confirm that. I've seen melting in plastic fin units of other rockets from Estes B and C motors.

Okay, I’m an idjit. I missed that you were already putting a BT 50 mount in. This should fly great on a 24mm D. IMO, I don’t see any need to put anything bigger in it, you have two parts to track, you don’t WANT this thing going any higher. And extending the length as you’ve said will easily counter the CG change from the D motor.

and the BT-55 will give you plenty of room for a baffle.

I am liking this. Not sure of the optics with the fatter bottom tube, but will make it a much more durable rocket and a better flier. Looking forward to your progress!

 

[BABAR]

Sorry, in post 2 I didn’t include the link

https://www.rocketryforum.com/threads/exo-skell-build-thread.36956/

 

[Back_at_it]

Finally got a chance to get back to this. Work was crazy busy with a new client and I normally don't have to work the weekends.

Continued work on the Main tube. Added the BT50/55 centering rings. The upper ring was attached at the end of the tube and the lower was attached approx. one inch down from the top. You will see in a later pic that I added two additional centering rings. I was not happy with the fit or stability of the lower tube in the upper BT55 tube. The additional rings tighten up the fit to my liking.



While the upper rings dried, I turned my attention to the baffle. These are from Qualman Rockets. The more I use these the more I like them. Very well made the fit and finish is near perfect.

This was glued together with TBII and let dry. I then brushed on a coating of TBII for a bit of fire protection.



In this pic you can see the additional two rings I added to the upper tube. These were just some old split rings I had from past rockets. I added a screw eye to the top of the baffle for the Kevlar Leader. 500# Kevlar was attached then the Baffle was inserted into the rocket approx. 4 inches down from the top of the tube.





Next it was time to work on the fins. The lower BT55 tube was marked for the fin locations. I then cut some rather sloppy lines in the body tube to peel back the outer layer for better adhesion. The root edge and the first 1/8" of the side of each fin was also sanded with 60 grit to give it a rough surface for the epoxy to adhere to.



All four fins were attached using BSI 30 min epoxy. At this point the fins are pretty solid but I'm going to go back with some fillets to add some strength.

 

[Back_at_it]

Made good progress last night. I love epoxy as it makes things happen fast.

Next up is the center ring that holds the legs in place when folded. Stock, this ring served as a reducer from the BT55 to the BT50. For our purposes we do not need the reducer portion. Only the upper section that attaches to the BT55 is required. In the next two pics you can see where I have removed the reducer portion. I basically just cut it off where it makes the bend to reduce down.



Using the landing pod for reference, I marked the tube where the upper and lower portion of the ring need to sit. For reference. The upper ring needs to sit 5-5/8" from the top of the tube. The inside of the ring was sanded with a 36 grit roll on my Dremel to give a rough surface for the epoxy. The area of the tube where the ring will attach was also sanded with 100 grit.

BSI 30 min. was then applied to the tube and the ring was slid up from the bottom and let cure.




At this point we have 4 completed sub-assemblies. The landing pod, The Upper BT55 tube with the ring, the main BT50 tube and the lower BT55 tube with the fins attached.



The main BT50 body tube was inserted into the upper BT55 tube approx. 1 inch until the last of the centering rings were even with the bottom of the BT55 Tube. Since I was working with Epoxy already, I went ahead and used BSI 30 min. for this connection as well. It was unnecessary but I wanted to wrap up the assembly and it seemed like the quickest way to do so.



Next up was attaching the lower BT55 tube with the fins attached. The attachment points on the BT50 main body tube were marked and sanded with 100 grit. BSI 30 min was spread on the main BT50 tube and the lower tube was slid on from the bottom until the tubes were flush at the bottom.



And here we get our first look at the completed assembly. The rocket now stands 24.5in tall. I can't find and exact number of the Exo-Skell stock. I've seen everything from 18.0 to 19.5 inches. So I have added somewhere between 4 and 6.5 inches depending on who you believe.

I'm happy with the new look. I never cared for the thin almost peg-legged look of the stock rocket with the fins attached to the BT50 tube. I'm hoping that increasing their width also helps with stability. I know they are not really larger in surface area but they do stick out further into the "clean" air.



Next comes fillets and I need to add a stand off for the lower launch lug as the one on the fins would not work and has been filled.

From there it's off to paint. I have a few ideas and have already purchased a new "alien skin" wrap for the main tubes.

 

[GlenP]

Nice job!

Do you have the original purple and orange chutes, or are you planning to make your own?

 

[Back_at_it]

Nice job!
Do you have the original purple and orange chutes, or are you planning to make your own?

I believe I still have the original chute. If so I will use it for the landing pod. The rocket itself is now heavy enough that It will need a larger 18" chute as well.

 

[KSoldier]

Awesome work, I have one of these still in my build stash. I plan to do a motor upgrade as well. The I plan to paint it in an "ALIEN" motif.

 

[BABAR]

Are the fin and ring lugs lining up?

very nice job, BTW, I really like this with a 24mm mount.

 

[Back_at_it]

Awesome work, I have one of these still in my build stash. I plan to do a motor upgrade as well. The I plan to paint it in an "ALIEN" motif.

only way to do a motor upgrade is to use a booster or do what I did and attach the fins directly to a different tube which mean not using the fin can

 

[Back_at_it]

Are the fin and ring lugs lining up?

very nice job, BTW, I really like this with a 24mm mount.

No. Since the fins are now sticking out much further, the original lug in the fin would not work.

the upper lug is centered between the fins so I’ll need to do a lug on a stand off.

 

[BABAR]

Take your time on the weathering, the contours are really striking when done well. I am guessing you may want to do that BEFORE applying the wrap.

 

[BABAR]

Awesome work, I have one of these still in my build stash. I plan to do a motor upgrade as well. The I plan to paint it in an "ALIEN" motif.

Before the QJets and the re-released C5-3 came out, IMO the 24mm mount (either by redoing the fin can as here or going with a booster style equivalent, as in post 7) was a big confidence builder for me in flights. I have read of people flying this, Venus Probe, and MIRV stock with C6 motors successfully, but my experience with the MIRV was miserable and I just put 24mm mount mods in ExoSkel and VP and they flew beautifully.

but I think the C5-3 and the QJet Ds may be game changers, and may allow successful flights built stock.

 

[Back_at_it]

Before the QJets and the re-released C5-3 came out, IMO the 24mm mount (either by redoing the fin can as here or going with a booster style equivalent, as in post 7) was a big confidence builder for me in flights. I have read of people flying this, Venus Probe, and MIRV stock with C6 motors successfully, but my experience with the MIRV was miserable and I just put 24mm mount mods in ExoSkel and VP and they flew beautifully.

but I think the C5-3 and the QJet Ds may be game changers, and may allow successful flights built stock.

I flew mine on a C5-3 that I still had a bunch of in the range box. While it was better than the C6-3, it was still a poor flight. It might have seen 200-250 feet max.

This thing really needs a Qjet or a 24mm motor. In my experience the Qjets get really hot. I’d be afraid of themmelting the fin can.

 

[BABAR]

In my experience the Qjets get really hot. I’d be afraid of themmelting the fin can.

good point on the QJets getting hot and melting the plastic.

I reviewed the curves for the C5 vs C6.

https://www.rocketreviews.com/compare-estes-c6-to-estes-c5.html
Kinda depends how long the rocket stays on the rod. A 4 foot rod helps, I don’t think going any longer does much because of rod whip. And the model definitely doesn’t lend itself to rail buttons.

I am L-0. I think the D12-3 is my favorite motor.

 

[GlenP]

I believe I still have the original chute. If so I will use it for the landing pod. The rocket itself is now heavy enough that It will need a larger 18" chute as well.

If you wanted to make your own, you could try to find some kind of Alien-themed mylar balloon at a party store or something like that, and cut one from it, maybe.

 

[Back_at_it]

The paint job on this took the better part of three days to complete but it was worth it. Really brought me back to my days with hard body RC Cars and models. The paint looks a little dark in the photos and it almost impossible to get all of the details to show up without zooming in on one specific area.

First the landing pod was disassembled. That is really the only way to get into some of these areas. Three screws and the whole thing pops apart on you Literally. Be careful and don't lose the screws. Sorry I don't have any in process pics.

I started with Duplicolor Emerald Green Met. One light coat was all that was required to get the coverage I wanted. I didn't want to completely cover the original color so this was sprayed on in a sort of haphazard way. A little heavy here, a little lighter there. The great thing about Duplicolor was that it was dry by the time I got back in the house. Of course it was 90ish degrees.

Next it was time for the wrap. I found a vinyl wrap online called Alien Skin. For around $7 I had a 12x24 sheet. The upper, middle and lower tubes were all wrapped. I chose to wrap the body before weathering as the weathering would help hid some of the seams.

Next I used thinned Tamiya Acrylic black paint. This was brushed onto each piece. I waited about 30 secs. then wiped it off with a damp towel. I did this a couple of times per piece until I got the look I wanted. There is no wrong or right way to do this. If you put on too much simply wipe it off with a wet towel. Too little and you just add more.

After letting that dry, I went back with a rust color on some of the areas that looked like they might be bolts, nuts etc. on the legs. Next was a gun metal silver to do some details on the legs. I also added a touch of the gun metal throughout the rockets and wiped it with a damp cloth to get a sort of exposed metal feel.

Again, this is a very hard rocket to photograph as it looks much darker than it actually is. I got lucky and we had a sunny day where I could get some pics in the back yard.

I still need to add the recovery gear and check the CG but i'm sure that it will be more than stable even with a 24MM "E" motor. I'll report back with that info at a later time.

 

[brockrwood]

Finally got a chance to get back to this. Work was crazy busy with a new client and I normally don't have to work the weekends.

Continued work on the Main tube. Added the BT50/55 centering rings. The upper ring was attached at the end of the tube and the lower was attached approx. one inch down from the top. You will see in a later pic that I added two additional centering rings. I was not happy with the fit or stability of the lower tube in the upper BT55 tube. The additional rings tighten up the fit to my liking.

View attachment 476687

While the upper rings dried, I turned my attention to the baffle. These are from Qualman Rockets. The more I use these the more I like them. Very well made the fit and finish is near perfect.

This was glued together with TBII and let dry. I then brushed on a coating of TBII for a bit of fire protection.

View attachment 476686

In this pic you can see the additional two rings I added to the upper tube. These were just some old split rings I had from past rockets. I added a screw eye to the top of the baffle for the Kevlar Leader. 500# Kevlar was attached then the Baffle was inserted into the rocket approx. 4 inches down from the top of the tube.

View attachment 476688

View attachment 476692

Next it was time to work on the fins. The lower BT55 tube was marked for the fin locations. I then cut some rather sloppy lines in the body tube to peel back the outer layer for better adhesion. The root edge and the first 1/8" of the side of each fin was also sanded with 60 grit to give it a rough surface for the epoxy to adhere to.

View attachment 476693

All four fins were attached using BSI 30 min epoxy. At this point the fins are pretty solid but I'm going to go back with some fillets to add some strength.

View attachment 476694

Cool!

 

[BABAR]

WOW! Unique and very cool, very ALIEN!

Regarding motors, suspect you will be great with the D12.

regarding the E—— why? I think you will get a very entertaining flight with the D and it is fun to watch it separate into two parts. However, sometimes the Muddaship goes one way and Junior the other. Not as big a deal at lower altitude, but the chance of losing one or both parts increases with altitude at deployment.

also, if you get weathercocking, once it goes off vertical, the more motor you have, the longer the walk And often the longer the search. Maybe you have a sod farm or a very large flat mown field. But depending on the depth of the grass and the bushes, your great color scheme may unfortunately be a great camo scheme as well. Hope you have brightly colored chutes!



hope you get many great flights, I have enjoyed mine.

 

[Back_at_it]

One last update until it flies. Total weight with the recovery gear packed is 6.4oz.

With an E12-4 loaded in the tail the CG is approx. 8.75 inches from the tip of the nose. A rather crude OR Sim of the rocket shows CP to be around 15.49 inches so it's more than stable.

 

[Back_at_it]

WOW! Unique and very cool, very ALIEN!

Regarding motors, suspect you will be great with the D12.

regarding the E—— why? I think you will get a very entertaining flight with the D and it is fun to watch it separate into two parts. However, sometimes the Muddaship goes one way and Junior the other. Not as big a deal at lower altitude, but the chance of losing one or both parts increases with altitude at deployment.

also, if you get weather cocking, once it goes off vertical, the more motor you have, the longer the walk And often the longer the search. Maybe you have a sod farm or a very large flat mown field. But depending on the depth of the grass and the bushes, your great color scheme may unfortunately be a great camo scheme as well. Hope you have brightly colored chutes!

hope you get many great flights, I have enjoyed mine.

Thank you for the kind words.

Looking at my OR sim, It looks like I'm going to get about 440ft on a D12-5 which is a nice low flight. As for the E motor, it looks like an E12-4 is expected to apogee around 753ft so that is well within my ceiling of recovery up at Bong. I like to have the option of putting something bigger in there without going to composites.

If I send this one out to AZ which I might do as I think the nieces will get a kick out of it. We might go E20 or E30 as we literally have about 4 square miles of flat land to recovery and more we can make them run the more peaceful the drive home will be

 

[neil_w]

Looking at my OR sim, It looks like I'm going to get about 440ft on a D12-5 which is a nice low flight. As for the E motor, it looks like an E12-4 is expected to apogee around 753ft so that is well within my ceiling of recovery up at Bong. I like to have the option of putting something bigger in there without going to composites.

Don't forget the 24mm Q-jets, those should put it up higher and faster than the BP motors, but not as much as the E20 or E30.

 

[Back_at_it]

The Exo-Skell has flown 6 times since I completed it and unfortunately, 5 of those 6 flights resulted in some type of damage.

The issues with this rocket are really three things. 1- It's heavy. 2- There is little room to pack two chutes into the body tube even after I lengthened it during the rebuild. 3- The plastic fins from the original kit are brittle and they hang below the body tube.

3 of the flights resulted in broken fins and 2 of them resulted in a kinked body tube. It's time to resolve all those issues and I no longer care that it won't look like the original rocket.

The last flight popped the lander and it came down fine without damage. The 18" chute on the booster opened partially but the brittle fins still broke and it kinked the small BT50 middle tube. This has been an issue on this rocket since the start.

I decided to pull off the lander, cut and remove the center ring that located the lander legs and build a complete replacement booster without the step down to the smaller tube. This reduces complexity so less weight and give me a full length of BT55 to pack wadding and chutes so reliability should be greatly improved.

The body tube is a single 18" BT55 with a 24mm mount. The new fins sit above the bottom tube so they are less likely to snap off. While they look small, they are actually a 1/4" longer and 3/8" wider than the original fins. The booster section is also 3oz lighter than the previous build.

 

[Back_at_it]

The majority of this rocket will be wrapped so only the fin section was primered and filled.

After sanding, I sprayed on two coats of duplicolor emerald green met.. Again, only spot painted as most will be a wrap.

Here is where we’re at now. I’ll be working on the wrap before work this morning.

 

[Back_at_it]

Back with the completed pics. I got up early this morning specifically to get the wrap completed on this. Thankfully I still had the same paint and the same alien skin wrap I used with the first rebuild so no waiting on things to get delivered.

Wrapped the upper and lower tubes by first marking a straight line on the tube then spraying the back of the vinyl with a water soap mix and rolling on the wrap. The fins and center retaining ring were left as bare paint.

I then packed up the rocket with wadding and two chutes, The lander has a 15" thin mil chute and the booster will come back on an 18" thin mil. Both now pack easily without any of the headaches of the previous design. Final weight is now 5.2oz packed ready to fly minus the motor so I knocked 1.2oz out of it when compared on the previous rebuild.

This one is done for now.

 

[loopy]

That looks amazing!