RW Go Devil 38 community build thread

To avoid hijacking the RW Rapton 38 thread or continuing to make posts on the Happy Hump Day thread, I wanted to create a thread specific to this kit. But I don't feel qualified to truly do my own build thread, I have more questions than answers when it comes to this kit so far. So I'd like to propose a "community build thread", where hopefully anyone else who ordered one of these might chip in on how they're handling certain details of the rocket. I'll start out with some questions I have.

First off, I'll note that RKeller has already put together an OpenRocket file for this kit, in this post. I haven't compared any of the weights / dimensions to my kit yet, but it looks reasonable at a quick glance.

1) Anybody have guidance on how far from the bottom of the rocket the fins should be? There are no instructions or plans provided by the vendor, I'm not sure if RKeller had any insight here or if he just guessed/eyeballed it. Is there any benefit to them being as far forward as pictured on RW's kit page? Seems like it would be an easy way to get another ~1" of CP back by moving them back, is there some other design that is the inspiration here, or is the room being left for a motor retainer, or...?

2) This is my first non-slotted fin setup, I built two previous MD rockets but they were both GLR kits with the Acme fin cans, so no learning there. The two triangular guides are provided to take care of the spacing and alignment, but I'm wondering about the actual attach to the airframe. I'm tempted to try a few dots of CA to hold the fins in place enough to remove the guides, and then apply a proper epoxy fillet the whole way around. But I also have no experience with FG (this is also my first FG kit), will CA stick the two FG parts together?

3) Still on the fins, since the colored FG lets the rocket look good without painting, I'm sensitive to putting ugly fillets on this kit. I've used 30 minute Z-poxy on my previous (wood + phenolic) builds, would that (presumably along with milled glass for strength) be good for this FG kit, or is a different epoxy needed for FG? I guess I'm going to try to figure out how to dye the epoxy black also, or is it easier to just try to paint it black afterwards? Since there is no TTW I'm also curious how big people think the fillets need to be, trying not to get carried away on an MD rocket, but it looks like it's hard to keep this kit under mach with any I motor I've sim'ed.

4) Also, is it a good idea to try to bevel these fins, or just leave them as-is? They're pretty thin (1/16"), and I suspect would look bad after trying to bevel (probably requiring painting of the fins to make look good again), so I'm leaning towards not touching them but I'm wondering if that's a bad idea.


For my build, I'm probably going to go with the Aero Pack M38E for motor retention and the wfcook/AMW fly-away rail guides to keep with the spirit of MD. I plan to skip the vent band and epoxy the upper half of the avionics bay coupler to the upper airframe (same style as the GLR Firestorm 54 bay design), where the upper bay bulkhead w/all-thread drops-in through the top of the upper airframe, and the rocket separates at the bottom of the avionics bay as well as the nose cone. I'm going to need access to the NC anyhow as I plan to put a tracker up there. I'll probably order a set of the avionics bay bulkheads without the center hole, as I'd rather drill an offset hole and use all-thread with an eye-nut at each end for the shock cord attachment, to ensure I can fit my electronics (either SLCF or EasyMini and a ~9V-sized LiPo) in the bay. And I'm thinking of APE's 38mm NC bulkhead for the top, to have an upper sled for an Eggfinder & LiPo. And for recovery probably just a streamer for the drogue and a 30" chute for the main.

I can help with #3, a little.

You don't need any "special" epoxy for FG. Make sure you thoroughly sand the surfaces. Then use your favorite. However ... 5 minute epoxy is probably too brittle and should be avoided. Aeropoxy, West Systems, Rocketpoxy, or even Bob Smith will do.

Some folks put dye in their epoxy to match the fin color. However, 30-minute eposy is usually clear, and from a distance, isn't super noticeable.

I think the proline epoxy is black already. Also I don't know if a little graphite or carbon black is an appropriate pigment for epoxy. Maybe someone else can comment. Are you going to use a cutter for the main chute?.

I'm going to try to do a standard DD. A TeleGPS in the nosecone, use the switchband, put a Raven in the ebay with a magnetic switch. Battery size to be determined but a small lipo may be a solution. Drogue in sustainer and main in the upper bay. Kurt

I think the proline epoxy is black already. Also I don't know if a little graphite or carbon black is an appropriate pigment for epoxy. Maybe someone else can comment. Are you going to use a cutter for the main chute?.

Click to expand...

Personally I have used carbon dust in some laminating epoxy to make a black fiberglass tube without any problems. I know graphite can be used just fine.

1) Anybody have guidance on how far from the bottom of the rocket the fins should be? There are no instructions or plans provided by the vendor, I'm not sure if RKeller had any insight here or if he just guessed/eyeballed it. Is there any benefit to them being as far forward as pictured on RW's kit page? Seems like it would be an easy way to get another ~1" of CP back by moving them back, is there some other design that is the inspiration here, or is the room being left for a motor retainer, or...?

2) This is my first non-slotted fin setup, I built two previous MD rockets but they were both GLR kits with the Acme fin cans, so no learning there. The two triangular guides are provided to take care of the spacing and alignment, but I'm wondering about the actual attach to the airframe. I'm tempted to try a few dots of CA to hold the fins in place enough to remove the guides, and then apply a proper epoxy fillet the whole way around. But I also have no experience with FG (this is also my first FG kit), will CA stick the two FG parts together?

4) Also, is it a good idea to try to bevel these fins, or just leave them as-is? They're pretty thin (1/16"), and I suspect would look bad after trying to bevel (probably requiring painting of the fins to make look good again), so I'm leaning towards not touching them but I'm wondering if that's a bad idea.

____________________________________________________________________________________________________________________________________________________________________________________________

1) Looks like 1.5 to 2 inches from the bottom. Comments?

2) Make a paper fin guide. Draw lines for the fins on the bodytube after roughing the fin area with sandpaper. Make sure you trail fit the fine guide and grind away a small area on the G10 guide at the base so there is a much less risk of "gluing" the G10 guide to the tube. Use an epoxy bead on the fin with the guide for final alignment along with the drawn line on the bodytube. I plan to do the fins one at a time. I would not depend on CA for the initial bond in this situation. I want all the "adhesion" I can get with a good product. Then mask and apply fillets.

4) I'd say either go with the squared edge or for esthetics, round the leading and trailing edge. I don't think "razor" sharp is going to add anything. (I'm going to round) Kurt

ksaves2 said:

Are you going to use a cutter for the main chute?

Click to expand...

No, I was planning on traditional DD, but I was thinking it would be light enough that I wouldn't need a chute in the lower bay, just a streamer. At least that was my thought, having never used a streamer even ~30 years ago when I flew model rockets. I was hoping to mount the M38E retainer pretty high up, to allow my Pro38 6GXL case to be used, which after the avionics bay coupler would probably only leave 5-7" in the lower airframe. So barely room for the shock cord let alone a chute. But I'll have to re-visit that once I actually get the M38E, rods and CTI adapter and try fitting everything, maybe I'll have to forgo my longest 38mm CTI case but I'd rather not if I have a choice. Though mine will have more electronics weight, a J150 sims to ~12k at 1350 ft/s in RKeller's setup. :y:


The 30min Z-poxy by itself sets fairly clear (though I think it has a bit of a yellow-ish tint to it), but if I mix in any of the glass fiber I have it becomes a rather milky opaque color. So that would look pretty terrible I think against red & black, which is why I'm wondering about dyeing or painting. I mixed in the fiber when doing the internal fillets on my Excel's fin can, wouldn't the stronger bond be desired here as well where the only fillets are on the outside?

Will,
for my open rocket file I measured and weighed each part. as far as the fin position, I just put them 1 caliber (diameter) from the back. I liked the way it looked. this rocket has a long L to D, (length to diameter). stability should be no issue. one might even want to build from the front back so you get a good idea of where your fins need to be. also, there are aerodynamic benefits to having 1 to 2 calibers behind the fins, although minor.

My kit came coated with some sort of polish or something. you HAVE to remove this before you do anything, even sanding. use Acetone or similar solvent to make sure the tubing is clean, then mark where your fins will be and sand the surface where the epoxy will be. I would not bond with CA first. there is a fair amount of strength to be gained at the root of the fin and CA is too brittle. just mix up a little epoxy and lightly butter the root and glue it down. chamfer the corner of the fin guides so they don't come in contact with your epoxy and you should be fine. that's my plan...

I'll be following with great interest as I also have one of these on the build pile. I'll also contribute to the discussion. Its a rocket that I am very eager to build as it seems like it will be a heck of a lot of fun.

I'm undecided on a motor retention solution. To keep my options open, I expect I'll position the fins to leave an inch to an inch and a half of tube free on the end.

I've had a chance to see the fly-away rail guides first hand. I like the concept and expect to pick some up for use with my Go Devil 38.

I've been using RocketPoxy for a lot of my recent builds and like it. I have black dye for it which I expect I'll use. This thread though might influence what direction I finally go though as I also have Proline epoxy which is black.

The av bay will more likely than not be based on one of the 38mm 3D printed sleds I picked up during the Black Friday sales.

I fly a Big Red Bee tracker in all of my rockets so always provide a space for them. In this rocket I will build in a small bay in the nose. The simplest way I have found to do this is order two of the stepped bulkheads. They will cover both ends of the small coupler that is the nosecone shoulder. The end up in the nose will be epoxied in place. All thread running through that bay will secure the bottom on providing removable access into that little bay in the nose shoulder.

I'm heading down to Red Glare in the morning. I only wish I had the rocket sooner to have it built to fly there with their 17k waiver. I'll take it for a spin at my home field with our 5k waiver once its built and then really take it for a ride sticking the biggest motor I can in it at LDRS.

Good luck with your build!

Jim Z

JimZNJ said:

I fly a Big Red Bee tracker in all of my rockets so always provide a space for them. In this rocket I will build in a small bay in the nose. The simplest way I have found to do this is order two of the stepped bulkheads. They will cover both ends of the small coupler that is the nosecone shoulder. The end up in the nose will be epoxied in place. All thread running through that bay will secure the bottom on providing removable access into that little bay in the nose shoulder.

Click to expand...

Now that is a really nifty idea that I would never have considered. Unfortunately I just checked, the Eggfinder PCB is a fraction of an inch longer than the provided NC coupler tube. So it would be even worse once a stepped bulkhead was on both ends of it. The battery I like to use (I have 5 identical 2s LiPos that move between altimeters/trackers) would also just barely fit in that coupler lengthwise. If that coupler was like 0.5" longer it would work beautifully, providing a little section at the very front to put the EF's antenna beyond the all-thread. Now to consider whether I stick with my plan or consider requesting a slightly longer coupler from RW (since I was going to re-order the un-drilled stepped bulkheads anyhow). I do like the thought of the APE part since then there's no metal other than at the very bottom, less to interfere with the EF's antenna, and my EF/LiPo barely fit in the diameter of the bay as well, adding an all-thread may totally break the fit while a 1/16" fiberglass sled would work quite well.


On the CA, I wasn't thinking of doing the entire root in CA, just a few drops (like maybe 3, one near each end and one in the middle, maybe just 2-3 spots between the two guides so the CA can't interfere with the removing the guides). Literally just to hold the fins in place long enough to remove the guides and do a proper epoxy fillet the whole way around. That's how I did almost every part on my Excel MMT/fin-can, first tacking the CRs and the like in place with a few evenly-spaced drops of CA (like ~120° around the MMT), then removing the fin can and applying generous epoxy where I could do a better job of it (nothing else like a pesky airframe in the way). So most of the root surface would still only see epoxy, and I wouldn't expect the CA alone to keep the fins attached even from a few inch drop, but just to hold things in place well enough to slide the guides off without the fins coming off or moving. I'm still inclined to try this, if the fins don't stay in place when I remove the guide then I'll obviously have to do something different. But yes, first to do the acetone wipe (well, first to buy some acetone).

If one has a Tele-GPS it is a workable nosecone fit in mockup. I've discovered with the new 1.6.0.1 firmware, the device can be programmed to transmit uncompressed packets and it works a lot better (more accurate) when using APRS radios as opposed to the Altus-Metrum receivers.

I had purchased a Tele-GPS some time ago to have on hand for very small projects. The GD38 nosecone assembly looks pretty perfect for it as long as I can get the 2-56 PEM nuts to make the NC coupler removable. I might consider a welded 8-32 or 10-24 eyebolt for NC bulkhead attachment as the prefect of our group has the welding "stuff" to close the open end.

Gotta mockup and see if a 720NS case can fit and the CG is not too outrageous. Kurt

Made the coupler removable with the N/C for TeleGPS mounting. I ordered some 2-56 PEM nuts and was looking at the
GD38 parts thinking about how to install the PEM nuts. I noticed the coupler is .070" thick. Hmmmmmmmm.

I lined up the first hole and figured, "What the heck. Just drill for 2-56 thread, tap the hole and see what I get."

Well, the little screw worked perfectly and due to the thickness of that blessed coupler, the PEM nuts will have to wait
for something else! Due to the thinness of the nosecone material, I really couldn't do a deep countersink so I switched from a finishing screw to a small stainless 3/16" buttonhead. Not "completely" recessed but good enough.

Just have to get a screweye. Am looking at 8-32 or 10-24 wire eyes as forged eyebolts are not available. I might consider asking the prefect to "close the eye" as I don't have welding equipment but I think an "open" eyebolt might be ok. Will mock everything up and then epoxy the nosecone bulkhead to the coupler.

I ordered some 1/16" G10 for sled material and little extra rocketpoxy from Rocketry Warehouse and lo' and beholden, (I wish I knew his name) two of the bulkheads with the center marked holes appeared in the box. Thanks very much! I was going to
do the inserts but this will give me a choice. I'll be able to make a press fit sled for the TeleGPS that slides in.
I'll just connect the battery, slide it into the nosecone, connect the coupler with the 3 screws and ready to go. Kurt

Fin prep here:



Along with the fin guides. I removed some material from the base with that dremel sanding cylinder on the fin guide.
Ol' stupidhead has to eat his words here as those guides will make it a cinch. Am going to do the fin mounting one at a time. I did a semi-sharp leading and trailing edges. I thought it harder to get a rounded edge.
I didn't know there were two guides until I read one of the posts here! Snapped right apart. I recommend one starts sandpapering the guides for tube and fin fit so's not to scratch up the tube of the fins too much. I have a few scars to contend with. Used 2000 grit on the scratches with decent results. The sanding marks at the root edge is a few swipes for the epoxy to hold to for fillets. Best to do before attaching to the tube. (I already wiped down everything with acetone)

Tube detail:




I used the guides for a rough position. Drew the lines and then roughed up the tube in advance with 80 grit.
Used a few swipes of 80 grit laterally on the root edge to try to get some epoxy holding "gouges" on the root edge
of the fins.

Another shot



This is going to be a cool rocket. Kudos to RW. Kurt

I knew I should have bought one of these when they were on sale, dang it.

Just a quick comment on the fly-away rail guides (full disclosure: I am the manufacturer). For this rocket I highly recommend the version that uses three standard rail buttons, as they are a little more durable and I have more confidence in them when flown with bigger motors.

Here is Nick Southern's AMW Parrot (built as a minimum diameter rocket) on an I800 Vmax this past weekend at Red Glare. The rail guides were recovered without a scratch except for a little black soot on them, but were otherwise undamaged and we used them again all afternoon and into the next day:

[video=youtube;YwNEI8ylBCA]https://www.youtube.com/watch?v=YwNEI8ylBCA[/video]

If you look closely you can see the guides clearing the fins about five feet off the rail.

Cheers, and back to your build thread. I am watching with interest!

I was at Red Glare over this past weekend and got to see the rail guides in action. I've also seen Nate fly them up at our club here in NJ. Well done Bill! Great design!

I picked up a set while I was in the AMW trailer. I opted for the version with the buttons as you suggest here. Hopefully in the next few days I'll get started on my Go Devil 38 and will be using the guides when I ultimately fly it.

I saw at least one Go Devil 38 in the air at Red Glare and was impressed by the performance. Eager to get mine built!

Jim Z

Fins on. I like the fin guides. Third fin on and the fillets next. I did them one fin an evening. Down and dirty OR sim from the file attached to the thread is 8000 and change with a J350.

Ok,

Some shots of the ebay. The Raven 3 "just fits" on top fo the 8-32 stainless steel all-thread.

That is the forward end of the ebay so one can see that the altimeter fits. It is going to be flush with the board so I need
to see where the baro chip is so it has access to ambient air inside the bay.



This is the aft end of the ebay with the 3 Dogs eyenut that unfortunately isn't available anymore.



Here is the tentative layout on the sled. That's a Featherweight Magnetic switch that is going to be used for on-off
services.



Another view from above. The ebay bulkheads I received had a 1/4" undersized hole I was able to tap and press-fiat an aluminum spacer for the aft end of the ebay and drilled the forward spacer to pass the 8-32 stainless all-thread.
The holes were undersized just a hair or my aluminum tubing was oversized so with the encouragement of a hammer, the spacer went in and is tight. Nonetheless, a flat washer will carry the load on the backside along with a lock washer.

My only problem is a battery. a 2s 25-40C 7.4 V lithium pack is too thick. I may have to ask Adrian what's the lowest
mah rating I can go. I believe this setup could be carried over to the Rapton too. Kurt

I think Adrian recommends a 1s 25C 130mAh battery for the Raven. My recollection is that larger LiPo's can send more current through the Raven than it can take, but you should confirm that with him.

wfcook said:

I think Adrian recommends a 1s 25C 130mAh battery for the Raven. My recollection is that larger LiPo's can send more current through the Raven than it can take, but you should confirm that with him.

Click to expand...

Thanks Bill, I'll try a note to him. I checked his forum but didn't see anything that would solve the issue of using it with his magnetic switch. 9V is way too large and since I use commercial matches that part
shouldn't be a problem. I use lipos with the trackers and can deal with charging issues quite easily. Kurt

Here's the mockup of the tracker nosecone with the cardboard tracker sled pattern I made last night after the second
set of fillets were applied to the fincan. The 1S 750Mah battery leads will be modified (shortened) later. Will be cutting some 1/16" G10 for the sled and the TeleGPS will fit antenna facing forward. Battery will be on opposite side and I expect I will use thrust blocks epoxied to the sled for fore/aft control of the battery pack and perhaps sticky tape to hold it to the sled. There isn't enough room in there for the pack to flip out and fly about.



Very rough sim estimates with OR and Rocksim are giving me between 7500 and 9000 feet and between Mach 1.26
and Mach 1.46. Those are with just using that stock .ork file posted here and not taking into account my weights and
building practices. I am gratified it likely won't be close to the 15,000 waiver at my local launchsite so I can fly with
less worry of busting the waiver. Kurt

More pictures of TeleGPS carrying nosecone. The stock parts just fit. The 1/16" G10 press-fits into the removable coupler. I epoxied the bulkhead in place yesterday with ProLine 4500. I like that stuff. Reminds me of Cotronics 4525B or 4525IP but without the price. (Sans the hi-temp guarantee and hefty price but that's fine) I put plastic tape at the bottom of the sled and applied the epoxy to the bulkhead/coupler and pressed it in. After 3 hours I popped the sled out of the coupler and there are formed indentations in the internal fillets between the coupler and the bulkhead. Nice close fit.



Hard to show the internals of the coupler. I found a stainless 80lb test wire eye I believe will work for the nosecone
and didn't have the capability to weld the eye shut. I'll be careful with the ejection charge.

Fincan with motor retention mocked up. I put a very fine strip of the blue 3M trim tape as the Aeropack is a slightly loose fit. Not a big deal and still very useable. I used the kevlar tape type for the shockcord and a Dino shockcord protector. Going to use a Dino 30" chute for the Main. Don't think a 36" will fit.



The fillets are done. Left to do is the epoxy job for the motor retention, terminal fabrication for the ebay bulkheads,
mounting of the 3.7V Lipo in the nosecone for the tracker and mounting of the Raven 3, Magnetic switch and 180mah lipo for the Raven. I constructed an EggTimer remote switch last night. Neat device but a bit too large for this project. Kurt

Made a little more progress tonight. Received the battery connectors for the 3.7V 180mah battery for the Raven 3 altimeter.
Adrian says it's fine to use with the magnetic switch. Soldered a battery connector on the 750mah 3.7V battery for the
Tele-GPS with the Tele-GPS mounted to the sled. I am going to mount the 750mah 3.7V on the opposite side of the sled and cut a 1/8" piece of plywood plate and drilled 4 holes so the nuts for the Tele-GPS stand offs fit right into. That gives me a flat platform on the opposite side for the battery. Will put a forward thrust block and might not need an aft one for the battery.

Have the ematch terminals epoxied to the ebay bulkheads. I just have to epoxy the opposite side to fill in the holes for the wires and I epoxied the MD Aeropack motor retainer last nite. Next time I use a syringe with tubing. I used a cardboard tube so I could stuff a glue stick down so's not to bum up the bay but a lot of the epoxy was lost in the cardboard tube. I pulled the tube out and slid in the motor bulkhead from the opposite side with the motor for sizing. I wrapped the shockcord in wax paper and made it easy to pull it off later so the shockcord didn't get bunged up with epoxy. Next time, I'll use silicone tubing on the syringe and shove it down the cardboard protection mask tube to get the epoxy right where it's needed. Also got out the Mayhem Rocketry fly away rail guides to test on a rail. REALLY nice! I just added a strip of duct tape proximal and distal to shim out the guide bit so the rocket is less likely to slide in the guide and have the guide slam into the fins. More pics to follow tomorrow to make things clearer.

Flew a WildmanJr on Saturday with an old AMW J440 BB. Fifth flight with that rocket that no one saw anything but the up side.
Beeline GPS took me right to it 1/2 mile away. Nice to see by the looks of it that all the recovery events were nominal. I'd say the
tracker paid for itself with the recovery of this and another project that have flown "never seen" profiles. Kurt. ( hit 6122' MSL)

I'm still waiting for my Proline to arrive (hopefully today, I want to fly this thing next weekend!) so all I've done so far was beveling the fins (though I think that turned out quite well for the jury-rigged setup I made to do it, more on that later). I did get my Aero Pack MD retainer this week and was playing with that, impressed with how the whole thing works. Curious, what's the biggest motor you plan to fly and how far up (or down) in the airframe did you put the MD retainer?

I'd like to be able to fly my 6GXL casing in this rocket, but that puts the retainer VERY close to the top once you consider the AV bay. I really need to put together all of the recovery bits this weekend and see if I can get everything to fit to set the final locations. I wasn't planning on using the vent band (epoxying the coupler into the upper tube instead) but I'll probably have to so that I don't lose too much recovery area in either the upper or lower tube. If I have to go down from 6GXL the problem is my next biggest casing is a 4G, so I'd have to guesstimate the position for a 6G casing and pick up one of those.

woferry said:

I'm still waiting for my Proline to arrive (hopefully today, I want to fly this thing next weekend!) so all I've done so far was beveling the fins (though I think that turned out quite well for the jury-rigged setup I made to do it, more on that later). I did get my Aero Pack MD retainer this week and was playing with that, impressed with how the whole thing works. Curious, what's the biggest motor you plan to fly and how far up (or down) in the airframe did you put the MD retainer?

I'd like to be able to fly my 6GXL casing in this rocket, but that puts the retainer VERY close to the top once you consider the AV bay. I really need to put together all of the recovery bits this weekend and see if I can get everything to fit to set the final locations. I wasn't planning on using the vent band (epoxying the coupler into the upper tube instead) but I'll probably have to so that I don't lose too much recovery area in either the upper or lower tube. If I have to go down from 6GXL the problem is my next biggest casing is a 4G, so I'd have to guesstimate the position for a 6G casing and pick up one of those.

Click to expand...

Biggest I'm doing is anything that fits in an AT720NS case. You need the threaded forward closure. I attached the shockcord, threaded the motor casing on the retainer part way and slid it in from below after the epoxy was slathered in from above. Wrapped the shockcord in wax paper for protection from the wet epoxy and made it so it pulled off easily once set. One fellow ordered longer tubes for longer motor casings in advance. Told me he got a longer upper bay from stock and longer sustainer tube.
Will be tough to use a 1320NS case in a stock setup but it's hard to know this in advance of getting the parts.

One other thing. Use a shockcord protector since you won't be able to get at the shockcord once the motor retainer/block is mounted. I used kevlar fishing line to sew the Dino protector to the motor block eyebolt so it stays in position. This is to
try to preserve the life of the shockcord as long as possible. I added duct tape too at the base as a further ablative. Kurt

Disclaimer: Nothing was destroyed in this exercise.

What's wrong with these pictures of a Featherweight Magnetic switch mounted on metal hardware?



Well....... All the standoff hardware is metal. I thought I came up with a really neat way to secure the 8-32 stainless
steel all-thread rod to the sled. Not!! If one looks carefully I setup everything for a dead short. Last I heard, stainless steel conducts electrons!! My other installs of the magnetic switch are in standard "dual" all-thread ebays with wing nuts.

Soooooo...... I can either ditch this and mount the mag switch on a wooden block and epoxy it to the G10 like I've done with another project..... Or I can try and electrically "float" the board on the standoffs. How? I have plenty of nylon washers and screws floating around here. Just ditch a few of the metal washers I used to "jack up" the standoffs/ magnetic switch so it was closer to the inside wall and use some nylon washers to "float" the board on top of the standoffs plus use nylon screws to secure the wires to the switch. I can epoxy thrust blocks forward and aft if I feel it necessary.

I used nylon hardware on a Peanut altimeter for the on/off screw switch so I could remote it. That altimeter design needed work. Two little screw switches on the board that were a PITA to deal with. May it rest in peace.

I'm going to float the board and go for it. Kurt

Hokay,

Used #4 nylon washers on the underside of the magnetic switch board along with 4-40 nylon screws.
The pictures show pigtails I used for continuity testing (there is none as it should be) and 9V power was applied with
no trouble to the switch. No smoke! Since there is plenty of room on the other side of the sled, I won't have to cut off the threaded legs of the standoffs. The whole assembly is rigidly mounted. As one can see, the sled is locked on the all-thread with the cockeyed washers, lock washers and nuts. Looks like floating the board is adequate
and the nylon screws hold the wires with authority. I used solid for the test but stranded is what's being used for internal connections.

The bottom (sustainer) end is where the black 4 screw terminals are. There's two, two pin terminals epoxied together with the posts shorted together for the positive bus of the Raven altimeter. (If one looks at the Raven wiring diagram at the Featherweight site you'll understand. Will mount the 180mah battery forward and come up with a removable forward thrust block arrangement. The Raven mounts aft and will likely just need one #2 nylon washer for a spacer/support.

The fit is very close with the "high" terminal block on the Raven. On another project, a modified AT HV ARCAS I did a very slight off center drilling of the bulkhead for the single all-thread to get a "leetle" bit extra headroom in the ebay. That rocket still flies after 13 flights H128's only. (fin flutter with anything of more power)

I show Bill Cook's fly away guides. I put just a "leetle" strip of duct tape fore and aft. I have a 1010 rail that I used to "trial" the fit. The guide holds the GDevil tube more securely to minimize the risk of it slamming into the fins on liftoff.
Oh, I made doubly sure no adhesive is displaced where it shouldn't be to impede the ejection of the guide once off the rail. Now on to the Raven mount, Raven battery mount and nosecone tracker battery mount. Kurt

O.K.,

Here's a shot of the Raven 3 mounted with the mounted Featherweight magnetic switch.



The battery is trialed in position. I had to purchase a connector off of ebay. I will set the battery connector in a plywood thrust block. Aft end to the sustainer is by the Raven connector. The black terminal block is "shorted" for
the common "+" bus. I will zip tie the battery in place and use dense foam for press fitting against the forward bulkhead. Prelim sim on a J350 is Mach 1.3 and 8 thousand or so in altitude. A 720 case is the largest I'm going to use. First flight will be with the J350.

Oh remember, the mag switch is floating on the metal standoffs with nylon washers and nylon 4-40 screws. I believe the screws will take the wire load under boost. At least I'll find out. I had a Peanut altimeter I installed a
remote switch with a 2-56 nylon bolt and it survived 88G's no problem. With the all-thread running down the middle, I didn't have the room to offset mount the switch so there is a dead short through the all-thread and the metal stand-offs. Look carefully at the past photos. Floating the board has taken care of that.
I did a sim test with the Raven programmer and sacrificed two ematches with that weak looking battery.
Worked fine otherwise I don't think Adrian would have a "Power Perch" that uses one!:wink:

Have the aft thrust block for the 750mah tracker battery for the Tele-GPS ready to secure. Will use fore and aft thrust blocks and use foam and/or double stick tape to keep it aligned in place. Space is at a premium and press-fit is the norm here. Kurt

Wow,

Just have the forward bulkhead for the nosecone tracker battery to epoxy in, wiring up the altimeter sled, cut slots for a ziptie for the 180mah altimeter battery (shown above), drill and tap holes to secure the ebay to forward main tube, drill static vent holes in ebay and finally drill holes in the nosecone coupler for the nylon shearpins. Not that much left to do.
Got the aft slotted plywood bulkhead for the 180mah altimeter battery epoxied in Sunday night. Is real nice. Plugs right in to the bulkhead epoxied socket and will use servo tape to help secure and use a ziptie to hold in. Will use dense padding on the forward end of the battery to hold in place also with the forward bulkhead. Pictures to follow when done. Kurt

It would be cool to see a Go Devil 54

The nose mounted Tele-GPS is done. 3.7V Lipo. Yes I had to get an aftermarket battery connector and yes the
polarity is reversed. Easy enough to lift the tab and swap the wires so red is + and black is - .
I apologize for some of the out of focus shots but the pics give the general idea. The process would be the same
for mounting a Tele-GPS in the same type of 38mm nosecone. Everything is press-fit except the plywood pad and the epoxied bulkhead and thrust blocks.



Battery sits on plywood pad with holes for the nuts. Makes it flat for the battery to sit. Yeah it's epoxied in place but the Tele-GPS is removable with the 4-40 buttonheads on the other side. Coupler is secured with three 2-56, 3/16" screws to the nosecone. I simply tapped the coupler for 2-56 threads and just lightly "finger tighten". No PEM nuts needed. Battery wires fit in a recess for the eyebolt nut and there is room so the wires don't bind or get compressed by the G10 sled. Made certain of that before the bulkhead was epoxied to the coupler.

All the parts were stock from the Go-Devil collection. No special order except I had to buy some G10 plate and
the stainless "wire" eyebolt. Rated for 80lbs but will be careful with the ejection charge.

Wired up the electronics sled and found out I dorked my unflown Raven III. That hurts. I had a clamp slip when applying a dollop of epoxy to the capacitor and I suspect it scraped the SMT parts on the opposite side of the board. It powers up but with the slightest of force on the board, it recycles or goes dead. Next time will use tape to
temporarily hold the capacitor to the board! My own stupid fault.

Once a new unit comes, will just have to drill and tap the upper bay to screw onto the electronics bay, drill the static ports on the switch band and do the holes in the nosecone coupler for the shearpins. I'm seriously considering 2-56 nylon shearpins in the sustainer too. At Mach 1.3 I'd worry about ascent separation there. Of course I will ground test all the charges. I believe for ground testing I will take a piece of plywood and temporarily mount an EggTimer Rocketry remote switch in the Ebay: https://www.eggtimerrocketry.com/page24.php
It is meant to remotely turn electronics on but it can handle sending current to a little ematch for a remote test.
I usually run long wires out of a static port or put an ematch charge on an empty engine casing for apogee testing but the design of this rocket, precludes that. Buttoning up the ebay with an ET remote switch will allow for easy remote ground testing of charges for size to give a clean break of the shearpins and recovery deployment.
AND of course, hoist the nose tracker up 10 to 15 feet in a tree and do a range check and finally put everything together with bare ematches, turn everything on and wait to make sure the Raven doesn't recycle or shutdown from Rf. I don't expect that to happen as I run a Raven II just behind a Beeline GPS inside the same ebay. No problems there but I will still test. Been burned in the past a couple of times from Rf and witnessed a devastating demise of a beautiful project from Rf dorking. Kurt

Got the replacement Raven today. I futzed with the old one but quite obvious I dorked the board. A slight twist and it goes intermittent as opposed to the new unit. I hit the terminal with a soldering iron but now remedy on the power input. Oh well. Using tape to hold the capacitor down while the epoxy cures. I used the old one for a "trial" and I get a better "pressure" free fit by sanding the corners of the terminal block. Once I finalize the fit on the "bricked" R3, I'll modify the new one. Kurt