"E" powered Pathfinder clone

This is my first build thread, my first mid-powered rocket and its a clone at that.

This whole thing started at Christmas when I got an Estes Engine Mount Accessories Pack w/ an "E" engine mount from my wife. :santaclaus: I hope she did not pay full price. Hobby People wants $10.75 for tubes and rings that I already have.

I posted a thread asking for E powered kit suggestions and Johnnie was nice enough to suggest the Pathfinder (Estes #1997). I got the plans from JimZ and placed my Semroc order. Thanks Johnnie! :wave:

Basically all I needed from Semroc for this build was the transition and the nose cone. The other parts I ordered are for an upscale (BT-80) Estes Tartar missile clone but that is another tread. Cheryl added a blemished BNC-80BB at not cost to my order. Thanks Cheryl! :wave:

Now I’m contemplating a 3x18mm cluster Big Bertha at the suggestion of Indiana.

Here is my parts list:
1 BT-60 (18” long)
1 BT-55 (18” long)
1 BNC-55AC, secant ogive from Semroc
2 RA5060 Centering rings
1 Estes “E” Engine motor mount kit, Christmas present
1 TA-5560A transition from Semroc
1 12” nylon parachute from Top Flight
SCK 400# kevlar thread
Tubular elastic, from Wal-Mart
1 Eye screw
Sheet of 1/8” balsa
Aerogloss Sanding Sealer
Krylon Auto Primer

Will it look like this?

https://www.rocketinabox.com/Viper-28.htm

First I built the motor mount per the kit instructions except I cut a notch to feed the Kevlar through. I also cut a shallow notch for the squiggly end of the engine hook. I masked the engine hook and painted the whole thing black. I always do this now-a-days, I think it adds to the fit and finish of the model.

It looks like the same model but the Viper's fins look rectangular and the Pathfinder's fins appear square.

I was planning on using the original paint scheme orange/white/silver. I'm kind of commited since I started putting orange paint on the fins already.

Keep going - it will look cool. I like that general style.

The Pathfinder uses a full 18” section of BT-60 aft of the transition and a full 18” section of BT-55 between the transition and the nose cone, so there is no tubing to be cut.

That is nice except I built this cool cutting jig that works great on tube that are BT-60 or smaller. I actually like cutting tubes now.

I smear white glue on the open ends of both tubes and let them dry. I do this for strength and to protect it from becoming brittle when I apply the Future floor polish. I heard on this board that Future applied to unfinished craft tubing makes the tubing brittle.

I also plan to paint the inside of the motor mount end of the BT-60 the same orange as the fin section of the rocket, another fit and finish thing.

I tied an 18” long piece of Kevlar to the engine tube feeding it trough the notch. Then I attached a 24” long piece of elastic to that to make the shock cord. That is probably too long and a waste of both expensive Kevlar and cheap elastic. There is probably a rule of thumb for the length of the shock cord but I don't know it. I’d imagine that the longer the better. I have recovery issues but we can talk about that later. irate:

Set aside that whole assembly for now.

I use three coats of Aerogloss Sanding Sealer on all the balsa parts; with a sanding of #220 between each coat. That seems to work great and gives me a finish as smooth as plastic but in those little 6-8oz bottles, it gets expensive. If that does not fill all the grain a layer or two of high build auto primer does the trick.

I just picked up this Minwax Lacquer Sealer from Home Depot and a whole quart was only $2 more.than the Aerogloss Maybe I’ll review the Minwax in a different thread but I’m not going to layer different products on the same model.

Rocketsmith said:

This is my first build thread, my first mid-powered rocket and its a clone at that.

This whole thing started at Christmas when I got an Estes Engine Mount Accessories Pack w/ an "E" engine mount from my wife. :santaclaus: I hope she did not pay full price. Hobby People wants $10.75 for tubes and rings that I already have.

I posted a thread asking for E powered kit suggestions and Johnnie was nice enough to suggest the Pathfinder (Estes #1997). I got the plans from JimZ and placed my Semroc order. Thanks Johnnie! :wave:

Basically all I needed from Semroc for this build was the transition and the nose cone. The other parts I ordered are for an upscale (BT-80) Estes Tartar missile clone but that is another tread. Cheryl added a blemished BNC-80BB at not cost to my order. Thanks Cheryl! :wave:

Now I’m contemplating a 3x18mm cluster Big Bertha at the suggestion of Indiana.

Here is my parts list:
1 BT-60 (18” long)
1 BT-55 (18” long)
1 BNC-55AC, secant ogive from Semroc
2 RA5060 Centering rings
1 Estes “E” Engine motor mount kit, Christmas present
1 TA-5560A transition from Semroc
1 12” nylon parachute from Top Flight
SCK 400# kevlar thread
Tubular elastic, from Wal-Mart
1 Eye screw
Sheet of 1/8” balsa
Aerogloss Sanding Sealer
Krylon Auto Primer

Click to expand...

You are more than welcome.

I too have modified my Pathfinder for the longer E motors...what I really want to fly it on are the 24mm E and F reloads...like theE18, F12 and F24 reloads...we'll see.

The BT-60 bodytube that came with my kit was damaged, so when I ordered a new tube from Semroc, I also picked up a baffle and better set of centering rings.

You will love the way the Pathfinder flies, straight as an arrow.

Johnnie

Next I used the fin guide to mark the large body tube for 4 fins and a launch lug. I used a piece of “L” shaped wooden molding as a straight edge to mark the fin lines whose edges are 1” from the motor mount end of the tube.

I then sanded the glassine of the body where the fins would be and redrew the lines where necessary. I’ve had a problem with the fins popping of the body as if only the fillets were holding the fins onto the body. I figure it’s a bad bond between balsa and cardboard and maybe sanding off the glassine will help.

I then sanded the root edge of the sealed fins to bare wood and glued them to the body with CA. Over the next couple of days I used Elmer’s Carpenter’s Wood (yellow) glue to build up the fin fillets.

Then I did something I’ve never done before. I used Elmer’s Wood Putty to build some more substantial fillets. I realized they are probably more decorative than structural. Next time I’ll use 30 minute epoxy. After sanding several times with #220, I put the launch lug on the rocket but that is a different story.

I’ve finished models and even taken them to a launches before and have forgotten to install a launch lug :cry:…so I’m very anxious about getting the lug on the model early in the process.

It does not make sense to me to have two small lugs at either end when you can have one big one in the middle…so that is what I did. The night before a launch, I installed the motor mount and a 1/8” lug so I could fly it the next day.

Saturday morning when I got to the launch it was pointed out to me that a 1/4” lug would be more appropriate because it should be flown off the larger Club launch pads. Since I didn’t have any 5 minute epoxy I took it home without flying it that day and installed the larger lug.

That is the story behind the picture below.

Rocketsmith said:

I posted a thread asking for E powered kit suggestions and Johnnie was nice enough to suggest the Pathfinder (Estes #1997). I got the plans from JimZ and placed my Semroc order. Thanks Johnnie! :wave:Now I’m contemplating a 3x18mm cluster Big Bertha at the suggestion of Indiana.

Click to expand...

The Pathfinder had some nice decals. I had the kit, but kitbashed it. I've still got the decals, and may build one at some point to use them. You might want to see if Excelsior or Tango Papa can create them for you, since you are building to the original colors -- it would be neat to use the same decal design. I could scan them if they do not have the originals.

I am building an Astron Cobra currently, which used BT-60 lower tube with 3X18mm motors. Its payload is BT-50. One of my favorites as a kid. I had the BNC-50K nose cone, and got the TA-5060 balsa adapter from Semroc. JimZ has the plans if you are not familiar with the Cobra, but want to check it out. Estes also made the Ranger, which looked like Bertha, but had 3X18mm cluster, and the rocket had BT-60 body with BT-60 payload compartment, instead of a one-piece 18" tube like the Bertha.

Here is a picture of the motor mount. I installed a threaded tube in center, and will use a 4-40 bolt and little washer to hold in the motors, rather than friction fit like the original. I did not want to spoil the classic look by using motor hooks. The other end has a stainless steel fishing leader (Walmart) epoxied into the other end, to use as shock cord anchor. I added a picture of the Cobra-in-progress. I dinged the adapter, so it is getting some filler and primer. I am using a new filler -- Elmer's Carpenters Filler, in a squeeze tube, Much easier to apply than Fill'n'Finish in the tub.

"The Pathfinder had some nice decals….You might want to see if Excelsior or Tango Papa can create them for you, since you are building to the original colors -- it would be neat to use the same decal design. I could scan them if they do not have the originals.”

Lee, I checked out Papa Tango and Excelsior and there were no Pathfinder decals listed. I would appreciate the scan. I have the decal page from JimZ’s for the Pathfinder but the quality is terrible. My original thought was to use Visio and recreate them on the Papillion brand waterslide decal paper I bought on-line. I have access to a color laser jet at work and have created some decals with good success others not so good. With a scan I can of the original I ask them how much it would cost to have really nice ones made. Thanks!

"Here is a picture of the motor mount. I installed a threaded tube in center, and will use a 4-40 bolt and little washer to hold in the motors, rather than friction fit like the original. I did not want to spoil the classic look by using motor hooks. The other end has a stainless steel fishing leader (Walmart) epoxied into the other end, to use as shock cord anchor. I added a picture of the Cobra-in-progress. I dinged the adapter, so it is getting some filler and primer. I am using a new filler -- Elmer's Carpenters Filler, in a squeeze tube, Much easier to apply than Fill'n'Finish in the tub."

That is what I will need to do with the upscale Big Bertha cluster although it will need to incorporate BT-80 centering rings. I never heard of a threaded tube before but I do have some threaded #4 rod I was going to use.

Do you use fishing leader because its cheaper than Kevlar by chance?

The Elmer’s Carpenters Putty was exactly what I used for the fillets above. Nice stuff to work with but I wonder how much structural support it adds…

Lee nice Cobra by the way can't wait to see the finished paint

Well back to the build. I was working a little out of order because I was trying to get to the launch on Saturday. Remember I coated the inside ends of the tubes with white glue to make them smoother, protect them from the floor polish but also so they would take paint nicer. I sprayed the inside and outside edge with the Testor Racing Orange paint. Again with the fit and finish thing. After it was dry I used 5 minute epoxy to install the motor mount noting the location of the launch lug and the engine hook so they would not be directly aligned…then the aborted launch the next morning...

Your gonna luv the Pathfinder clone when you do get a chance to fly it...it is a nice rocket...if you get a chance to fly a 24mm reload, hit that rocket on an F12 from Aerotech...if it is light enough, it will make you proud!

Johnnie

Rocketsmith said:

Lee, I checked out Papa Tango and Excelsior and there were no Pathfinder decals listed. I would appreciate the scan.

Click to expand...

I will scan this evening. PM me with your email, since the file wil be large. Happy to help out.

Rocketsmith said:

That is what I will need to do with the upscale Big Bertha cluster although it will need to incorporate BT-80 centering rings. I never heard of a threaded tube before but I do have some threaded #4 rod I was going to use.

Do you use fishing leader because its cheaper than Kevlar by chance?

The Elmer’s Carpenters Putty was exactly what I used for the fillets above. Nice stuff to work with but I wonder how much structural support it adds…

Lee nice Cobra by the way can't wait to see the finished paint

Click to expand...

Well, I actually mis-spoke, calling it a threaded tube, although that is technically what it is. The threaded tube is the center piece of a clevis pin from the RC airplane world. I just clipped off the two thin "arms" that snap onto control horns. I used this since the space is so small, and a threaded insert would not fit. I did not want to use a threaded rod, since it would hang down, and detract from the appearance of the rocket (much as using engine hooks would detract from the look). By the way, with you using BT-80, there might be room between tubes to place a T-nut on the back side of the centering ring, and use this as you anchor for a bolt with washer holding the motors in place. The 18mm tubes (BT-20) used in the BT-60 on the Cobra fit perfectly snug, so no centering rings can be used. You actually need to pack a filler into the gaps (the old technique is glue-soaked TP or Kleenex - in order to form a gas seal).

I use Kevlar alot in recovery assemblies, but I like using stainless as the anchor. It should hold up to heat better, and I can still add Kevlar to it to run up to the top of the tube, and then tie on a shock cord at that point. The last ones I bought were 4" long, so they make a nice compact metal anchor. Walmart sells them in lengths up to 18", and I think I saw them longer.

I'd say the filler is cosmetic, it will not add strength. I am a big fan of yellow glue for model rockets, since its holding power is incredible. But, it sometimes bubbles under lacquer paints. I use epoxy occasionally for fillets on bigger rockets, like this Cobra. But, even after doing this, sometimes there are small voids. The fillers help cover up the little blemishes. On the epoxy fillets, I do wipe most off with a gloved finger dipped in lacquer thinner. The epoxy gets spread really thin, and pressed into the joint, and minimal sanding is required. It is almost like a structural filler, and not looking like a big fillet like I might have put on an HPR model in the past.

The Cobra is gonna get a classic paint job, maybe white and black, with a dark blue nose cone, like I recall seeing in one of the really old Estes catalogs. I will post some build progress. For me, this is a very nostalgic build -- and when I was a kid, the Cobra seemed so big!

I remember the pathfinder. was one of my favorite rockets. Loved flying that with D12-5's. I always had the itch to clone a new one.

Why a 1/4" launch lug? 3/16" is fine for that rocket. Unless your club does not use 3/16"?

n3tjm said:

I remember the pathfinder. was one of my favorite rockets. Loved flying that with D12-5's. I always had the itch to clone a new one.

Why a 1/4" launch lug? 3/16" is fine for that rocket. Unless your club does not use 3/16"?

Click to expand...

You guessed it! The larger club pads have 1/4" rods and there always seems to be a free pad during every launch round. Even when the large scout groups are there and the small pads are full...:captain:

Ok the build is on the home stretch now. My plans for Friday night were cancelled so I will finish painting it this weekend. After two coats of Krylon auto primer and a light sand with #220, I masked and bagged the model just above the fins and 61/2” above the motor mount end of the bottom half of the model. I then shot the bottom with two light coats of Krylon gloss white. On the upper half I painted only those areas which I’ll mask tonight gloss white and the area underneath the tape will become the two, 3/8” wide, white stripes.

Rocketsmith,

I scanned the decals. I saw your email tonight, and did not realize there was an email link in our profiles. I'm sending now.

Thanks much Lee! I got the scan.

arty:

Ok finally painted the assembled model. Using Lee's scan of the decals I pinged Excelsior and Papa Tango to see how much I would cost to have ALPS printed decals made. Failing that I'll print some on my color laserjet at work. I did add the black stripe decal separating the orange from the white. Even with blue painter's masking tape the transition between the two was a little rough in spots. The Krylon Chrome has a great finish; much better than any silver paint I've worked with. Just don't touch it untill it is completely dry plus one day. Get finger prints in it and you are screwed because you can't sand them out without ruining the metallic finish.

Once I apply the decals I'll put on the coat of Future.

So here is the model which will make it maiden flight this Sunday at the SCRA launch. Next I'll be packing the parachutes but that probably wont happen till late this week. :surprised:

Well, it been nearly a month since I've had good news to report on this build.

As I reported last the model was together and I was ready to launch the following Sunday. Well Sunday came and when it finally came my turn to launch the problems continued. :surprised:

First the 1/4" lug I used wouldn't fit on the 1/4" rod (too tight) It wasn't a launch lug at all but a piece of aluminum tubing with a slightly smaller inside diameter.

I so I moved it to a 3/16 rod we had available that round. The burn was perfect but the rocket did not leave the pad. I was truely embarrased when the nose cone blew and deposited the laundry all over the ground by the pad

The Estes style engine hook got caught on the pad itself which held the Rocket down. There was plenty of time for another launch but I was so angry I took my rocket and I went home.:cry:

Well third time is the charm. The two week delay gave me time to prune the engine hook with a pair of pliers and take deliver of a new lime green 15" Topflight parachute. Today's launch went off without a hitch.

Very nice flight on an Estes E9-6. Plenty of altitude.

Perfect chute!

Slight impact damage to the upper tube at the transition which will have to be repaired but that in another story.

I'm very happy today!

arty:

:congrats:
Thanks to Lee Reap for the Pathfinder decal scan. I emailed it to Phred at Excelsior and was kind enough to make it available in Classic Waterslide decals/ESTES. The cost is $8.00.

The model was slightly damaged on its third flight but the decals arrival next week will be a gread reason to make the necessary repairs.

Thank you Phred
arty: