I'm really glad this can help. I sometimes wonder if anyone finds my build threads useful, I don't usually get many comments or replies.
Performance Hobbies Performer 150, My L3 Cert Build
- Thread starter Handeman
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I'm really glad this can help. I sometimes wonder if anyone finds my build threads useful, I don't usually get many comments or replies.
I'm doing internal fillets on the fin to MMT right now. Not much to show on that. I just reach in with a dowel that has a little wooden ice cream spoon taped to it and spread the epoxy where it's needed. It's slow going, but the epoxy has a 30 - 40 minute working time and it's only about 68 deg in the basement where I'm working so it's closer to 40 minutes then 30. Not that it matters much, it doesn't take that long to lay in the internal fillets, even when you take your time.
While that was setting up, I did some more work on the av-bay. Here's a schematic of the av-bay, actually half of the bay. Each board will be identical and of course redundant to each other.
The reason I added the screw switch for the main power was because the Remove Before Flight On/Off switches were "activate" when the pin was inserted through the vent port and guide tube so the switch shut off the altimeter. That meant I had to turn the altimeters ON when I put the upper payload tube onto the av-bay and then turn them back OFF once the tube was attached to the av-bay. Of course at some point this would occur with the deployment charges in place.
I usually power up the altimeters with the ematches are installed, but before the powder is put in place. This lets me verify the connections of the altimeter and the ematches. In this case I needed some way to power down the altimeters with the Remove Before Flight pins removed. The screw switches are accessed through the av-bay in the area that is covered by the booster BT. I think I will also put a piece of tape over them to prevent those holes from affecting the sensing of the vent holes after apogee.
Anyway, here is how I soldered things up. I'm using the snap on power connector for the 9 VDC battery. The screw switches were part of a batch of them I made years ago. I've been using some of that batch in my L1 & L2 DD rockets for years now and they have never given me any problems and have been completely reliable. I didn't always remember to bring a screw driver out to the pad at first, bu now it's second nature.
I connected the red power wire from the battery connector to the black wire on the switch, that allows the red wire from the switch and the black wire from the connector to be used through the board and connected at the altimeter. The following pics show the soldering sequence and the use of 3/32 shrink tubing to insulate the soldered joint.
Here's the final set up. The wires will be hot glued to the board once the batteries and altimeters are in place.
I know the piece of Oak and the JB Weld holding the screw switch in place doesn't look very good, but it is very functional and very sturdy.
While that was setting up, I did some more work on the av-bay. Here's a schematic of the av-bay, actually half of the bay. Each board will be identical and of course redundant to each other.
The reason I added the screw switch for the main power was because the Remove Before Flight On/Off switches were "activate" when the pin was inserted through the vent port and guide tube so the switch shut off the altimeter. That meant I had to turn the altimeters ON when I put the upper payload tube onto the av-bay and then turn them back OFF once the tube was attached to the av-bay. Of course at some point this would occur with the deployment charges in place.
I usually power up the altimeters with the ematches are installed, but before the powder is put in place. This lets me verify the connections of the altimeter and the ematches. In this case I needed some way to power down the altimeters with the Remove Before Flight pins removed. The screw switches are accessed through the av-bay in the area that is covered by the booster BT. I think I will also put a piece of tape over them to prevent those holes from affecting the sensing of the vent holes after apogee.
Anyway, here is how I soldered things up. I'm using the snap on power connector for the 9 VDC battery. The screw switches were part of a batch of them I made years ago. I've been using some of that batch in my L1 & L2 DD rockets for years now and they have never given me any problems and have been completely reliable. I didn't always remember to bring a screw driver out to the pad at first, bu now it's second nature.
I connected the red power wire from the battery connector to the black wire on the switch, that allows the red wire from the switch and the black wire from the connector to be used through the board and connected at the altimeter. The following pics show the soldering sequence and the use of 3/32 shrink tubing to insulate the soldered joint.
Here's the final set up. The wires will be hot glued to the board once the batteries and altimeters are in place.
I know the piece of Oak and the JB Weld holding the screw switch in place doesn't look very good, but it is very functional and very sturdy.
The next up was the ON/OFF switch for the altimeters. These are mounted to the board with 4-40 screws, washers, lock nuts, and nuts. The guide tubes for the pins (finishing nails) are JB Welded in place. I found out on my L1 rocket that 5 min epoxy doesn't cut it. The JB Weld is great for this.
The wires are cut to different lengths because they are routed away from the switch to the side. The wires are stripped and wrapped through the holes in the switch spades.
The solder is then melted onto the wire and the spade. I found putting the soldering iron against both the wire and spade at the same time and then pressing the solder against the wire and spade on the opposite side of the soldering iron works very well. When the solder melts, it flows back toward the iron and attaches to both the wire and the spade. This gets plenty of solder to hold the wire to the spade, but doesn't over heat the spade causing issues with the switch.
Next up is the altimeter mounting, but that will be left for another day.
I did want to comment on how I twist the wire together. It's pretty simple. I bent a finishing nail that I put into a drill bit and then clamp the other end of the wire in my vise. Run the drill, holding tension on the wire, until it is twisted as much as you want. Then release the wire from the vise, don't release the tension on the wire first. If you release tension, the wire will twist up in loops. If you release the end from the vise, the wire will spin a little bit, but won't form loops.
The wires are cut to different lengths because they are routed away from the switch to the side. The wires are stripped and wrapped through the holes in the switch spades.
The solder is then melted onto the wire and the spade. I found putting the soldering iron against both the wire and spade at the same time and then pressing the solder against the wire and spade on the opposite side of the soldering iron works very well. When the solder melts, it flows back toward the iron and attaches to both the wire and the spade. This gets plenty of solder to hold the wire to the spade, but doesn't over heat the spade causing issues with the switch.
Next up is the altimeter mounting, but that will be left for another day.
I did want to comment on how I twist the wire together. It's pretty simple. I bent a finishing nail that I put into a drill bit and then clamp the other end of the wire in my vise. Run the drill, holding tension on the wire, until it is twisted as much as you want. Then release the wire from the vise, don't release the tension on the wire first. If you release tension, the wire will twist up in loops. If you release the end from the vise, the wire will spin a little bit, but won't form loops.
JDcluster
Well-Known Member
Didn't Tripoli and or the NAR outlaw micro switches?
JD
JD
I believe they outlawed pull pin switches for staging. Where the separation of the stages cause the switch to close and fire a motor. I don't believe the ban had anything to do with av-bays and altimeters.
Ok, progress has been slow. Still doing internal fillets on the fins. Just a few of the internals between fin and BT left. Then it will be time to clean up the drips and drops in the aft end of the BT. Can you say dremal? The 1/2" sanding wheel is probably my most used bit on that. I just need to clean up a little so the aft CR goes back in.
Anyway, more pics of that when I start attaching the aft CR and AeroPak retainer.
For now, it's time to get the altimeters mounted. I'm using an older Perfectflite HiAlt45 and a new StratologgerCF. When I bought the new Stratologger, I also orders three sets of mounting hardware. I should have ordered 4. Each set comes with 5 sets of mounting pieces so getting 4 sets actually gets you 5 sets since you only need 4 screws from each set.
Here one post is in the board already
The kit comes with lock washers, which may be fine on a circuit board or fiberglass, but not so good on a wood board. Here I added flat washers of my own before adding the lockwashers and nuts.
With the altimeters mounted on the back side of the board, it was time to wire things up. I used 22 ga stranded wire and twisted it together. With a battery tie wrapped to the board, i routed the wires on the power side of the board. I used a hot glue gun to tack the wires in place on the board and in the hole where they go to the other side.
Here's the front and back of each board. Other then the mounting holes for the two different altimeters, both boards ares close to identical as I could make them.
That's all for now folks...
Anyway, more pics of that when I start attaching the aft CR and AeroPak retainer.
For now, it's time to get the altimeters mounted. I'm using an older Perfectflite HiAlt45 and a new StratologgerCF. When I bought the new Stratologger, I also orders three sets of mounting hardware. I should have ordered 4. Each set comes with 5 sets of mounting pieces so getting 4 sets actually gets you 5 sets since you only need 4 screws from each set.
Here one post is in the board already
The kit comes with lock washers, which may be fine on a circuit board or fiberglass, but not so good on a wood board. Here I added flat washers of my own before adding the lockwashers and nuts.
With the altimeters mounted on the back side of the board, it was time to wire things up. I used 22 ga stranded wire and twisted it together. With a battery tie wrapped to the board, i routed the wires on the power side of the board. I used a hot glue gun to tack the wires in place on the board and in the hole where they go to the other side.
Here's the front and back of each board. Other then the mounting holes for the two different altimeters, both boards ares close to identical as I could make them.
That's all for now folks...
Sevian
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Fantastic building! I hope one day to capture your finesse when it comes to building rockets!
A couple of questions if you don't mind of course, it'll help out with my Level 2 (and 3 one day hopefully) build:
Is your 98 6XL case longer than your MMT? Does it matter if it is?
I didn't see you mention it, probably because you didn't need to, what sandpaper did you use to rough up the FG at epoxy locations?
Thank you!
A couple of questions if you don't mind of course, it'll help out with my Level 2 (and 3 one day hopefully) build:
Is your 98 6XL case longer than your MMT? Does it matter if it is?
I didn't see you mention it, probably because you didn't need to, what sandpaper did you use to rough up the FG at epoxy locations?
Thank you!
I don't have the Pro98 6GXL case, wish I did, but it would definitely be longer than the MMT. Most of my rockets fly some cases that are longer then their MMT. No it doesn't matter.
...unless you have a situation like I had on one of my other rockets. The u-bolt was between the 54mm MMT and 4" BT. When the quick link was attached and pulled tight, the quick link wants to turn 90 deg to the u-bolt. There isn't enough room for it to do that and it would bind against the motor tube. My concern, and I don't know if it is a valid concern, is that the quick link could damage the motor casing if recovery forces cause it to twist into the motor case, or the shock cord, being attached on one side, could put a lot of bending forces on the motor case that extends out of the MMT due to side loads.
That is the reason I used a Kevlar bridal that extend out of the lower BT to attach the shock cord to. I suspect I'm being overly cautious, but... it makes me feel better, is as strong as u-bolts and probably weighs less.
I've been using 150 grit for sanding the fiberglass before using epoxy. I have some 120 grit that gets used once in a while also.
Good luck on the L2!
Sevian
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Maybe my subconscious is telling me to buy one at some point
Thanks for the luck! That also does seem like a valid concern about the u-bolt and quick link, might just scruff up the case but I suppose it could always put a dent in it if the force is great enough.
Maybe my subconscious is telling me to buy one at some point
Thanks for the luck! That also does seem like a valid concern about the u-bolt and quick link, might just scruff up the case but I suppose it could always put a dent in it if the force is great enough.
I didn't worry about with my L1 rockets, but by the time I was flying 10 lb L2 birds, it became a concern. Again, I don't know if it should be a concern, but I felt the peace of mind is worth a few ounces of prevention rather then pounds of $$$ to cure a bent L2/L3 motor case.
I'm finally back to this build, its been about 2 weeks. I got the inside fillets done which isn't too interesting and not much to tell about that.
The next thing before the aft CR was to put a piece of backing in the tube for the aft rail button. This will be launched off of our "away cell" which is a trailer launcher with uni-strut. So I'm installing uni-strut buttons using 1/4-20 flat head screws. To give this more bite, I epoxied a piece of oak inside the BT.
I then drilled a 3/16" hole and tapped that with a 1/4-20 tap.
Finally, mounting the button.
I didn't mount the forward button. I am planning on putting it just above the forward CR, but that is only about 30" above the lower button. I'm going to talk it over with my TAP tomorrow. It might get mount a little further up the BT.
The next thing before the aft CR was to put a piece of backing in the tube for the aft rail button. This will be launched off of our "away cell" which is a trailer launcher with uni-strut. So I'm installing uni-strut buttons using 1/4-20 flat head screws. To give this more bite, I epoxied a piece of oak inside the BT.
I then drilled a 3/16" hole and tapped that with a 1/4-20 tap.
Finally, mounting the button.
I didn't mount the forward button. I am planning on putting it just above the forward CR, but that is only about 30" above the lower button. I'm going to talk it over with my TAP tomorrow. It might get mount a little further up the BT.
The aft CR turned out to be a bigger "issue" then I thought it should be. Mostly because I wanted to put some thick epoxy inside and let that flow down to the CR before I put the fillet between the CR and BT.
Because of misplaced epoxy while doing the internal fillets, the Dremal got a pretty good workout cleaning up the BT, MMT and aft edges of the fins. Once everything was cleaned up and the CR fit the way it was supposed to, bottom face flush with the aft edge of the MMT, I was ready to mount the Aeropack. The reason the MMT is flush with the CR is because of the way the Aeropack is mounted. The instructions say to put some tape on the outer face of a motor tube to take up any slack and slide that into the MMT and the Aeropack over that. The tape takes up any slop in the fit and makes sure the Aeropack and MMT are aligned as close as possible.
I didn't have a 98mm Motor so I used a 4" fiberglass coupler tube. It worked just as well. With the CR in place, the taped coupler fit snug in the Aeropack and MMT, I marked the CR for drilling the mounting holes. I followed the Aeropack instructions and tapped the holes for 6-32. With the coupler tube back in the MMT and the Aeropack aligned to it, I put the screws in place. Once that was done, the aft CR with the mounted Aeropack was pulled back out and the coupler tube removed.
I did have to use the dremal to notch the oak block for the rail button to make sure one Aeropack mounting screw cleared the block.
I'm sure there were several ways I could have epoxied the aft CR in that would have worked just as well. What I did was to put the CR in place, used the coupler to align the Aeropack, mount the Aeropack onto the CR, remove the alignment coupler and then epoxy the CR in place.
The reason I did it this way was because I wanted to put epoxy inside the rocket and let it flow down onto the CR to form fillets on the inside. I was concerned that some of this could leak through between the CR and Aeropack and epoxy the coupler tube into the MMT. As it turned out, that is exactly what would have happened if I had left the coupler tube in place.
After putting thick epoxy inside the rocket and putting the CR in place, I stood it on end so it rested on the Aeropack. After a couple of hours I check it, epoxy was no longer flowing, but still soft. It had leaked through between the MMT and run down the insides of the Aeropack. A little denatured Alcohol and some elbow grease cleaned it up real nice.
This is after it was cleaned up. It's hard to see where the epoxy had run down the inside of the BT also, but it did.
With the Aeropack cleaned up, the last thing was to put a fillet between the CR and the BT. I use the US Composites 3:1 thick epoxy again, but this time I added West Systems 406 Colloidal Silica. I used 30cc of resin and 45cc of the silica. This made a thick mixture that was easy to spread, but didn't flow after it was put into place.
I drilled the upper BT and nosecone for shear pins also. I'm using four 4-40 nylon screws. I placed them directly below the screws holding the nose cone to the nose cone shoulder. I also put them about 2" from the bottom of the nose cone shoulder. You can sort of see the shadow of the shoulder in this pic.
I also intend to use two 4-40 screws as shear pins for the av-bay to booster connection, but I want to discuss how many to use with my TAP tomorrow. I intend to ground test everything tomorrow so I may even have videos!
Other than the booster shear pins and upper rail button location, I think this is about finished! Except for the paint.
Any suggestions for a paint scheme would be greatly appreciated.
Because of misplaced epoxy while doing the internal fillets, the Dremal got a pretty good workout cleaning up the BT, MMT and aft edges of the fins. Once everything was cleaned up and the CR fit the way it was supposed to, bottom face flush with the aft edge of the MMT, I was ready to mount the Aeropack. The reason the MMT is flush with the CR is because of the way the Aeropack is mounted. The instructions say to put some tape on the outer face of a motor tube to take up any slack and slide that into the MMT and the Aeropack over that. The tape takes up any slop in the fit and makes sure the Aeropack and MMT are aligned as close as possible.
I didn't have a 98mm Motor so I used a 4" fiberglass coupler tube. It worked just as well. With the CR in place, the taped coupler fit snug in the Aeropack and MMT, I marked the CR for drilling the mounting holes. I followed the Aeropack instructions and tapped the holes for 6-32. With the coupler tube back in the MMT and the Aeropack aligned to it, I put the screws in place. Once that was done, the aft CR with the mounted Aeropack was pulled back out and the coupler tube removed.
I did have to use the dremal to notch the oak block for the rail button to make sure one Aeropack mounting screw cleared the block.
I'm sure there were several ways I could have epoxied the aft CR in that would have worked just as well. What I did was to put the CR in place, used the coupler to align the Aeropack, mount the Aeropack onto the CR, remove the alignment coupler and then epoxy the CR in place.
The reason I did it this way was because I wanted to put epoxy inside the rocket and let it flow down onto the CR to form fillets on the inside. I was concerned that some of this could leak through between the CR and Aeropack and epoxy the coupler tube into the MMT. As it turned out, that is exactly what would have happened if I had left the coupler tube in place.
After putting thick epoxy inside the rocket and putting the CR in place, I stood it on end so it rested on the Aeropack. After a couple of hours I check it, epoxy was no longer flowing, but still soft. It had leaked through between the MMT and run down the insides of the Aeropack. A little denatured Alcohol and some elbow grease cleaned it up real nice.
This is after it was cleaned up. It's hard to see where the epoxy had run down the inside of the BT also, but it did.
With the Aeropack cleaned up, the last thing was to put a fillet between the CR and the BT. I use the US Composites 3:1 thick epoxy again, but this time I added West Systems 406 Colloidal Silica. I used 30cc of resin and 45cc of the silica. This made a thick mixture that was easy to spread, but didn't flow after it was put into place.
I drilled the upper BT and nosecone for shear pins also. I'm using four 4-40 nylon screws. I placed them directly below the screws holding the nose cone to the nose cone shoulder. I also put them about 2" from the bottom of the nose cone shoulder. You can sort of see the shadow of the shoulder in this pic.
I also intend to use two 4-40 screws as shear pins for the av-bay to booster connection, but I want to discuss how many to use with my TAP tomorrow. I intend to ground test everything tomorrow so I may even have videos!
Other than the booster shear pins and upper rail button location, I think this is about finished! Except for the paint.
Any suggestions for a paint scheme would be greatly appreciated.
I did some ground testing. The results were mixed. The baffles do seem to greatly reduce the need for a chute protector, but at the same time, are causing damage to the face of the av-bay.
What you see there is from one charge. It did burn the FG face some. I don't think it would take many firings to do significant damage.
The question becomes, what do you protect, the fiberglass av-bay and BT, or the recovery gear and chute?
I'm choosing to protect the recovery gear and chute. Dog barf is cheap and easy.
I'll be changing out the mounting screws for the charge cups and the baffles will go in the recycle bin. Since they were bought off a closeout shelf at Lowes, I might be able to get as much for the scrap copper as I paid for them.
It was an interesting experiment.
I thought of that and also using aluminum tape on the av-bay face and inside of the BT. Either way, what it really needs is a third cylinder to direct the gases back forward. That should provide enough change of direction to keep burning particles from hitting recovery items while protecting the av-bay face. This rocket needs 3 - 4g of FFFF which is quite a bit and a baffle may not be feasible. Even with the baffles it may throw flames too far because of the amount of BP needed.
Further testing is probably needed and I'm sure something can be worked out, but I'm hoping to fly this next month so I'm going with a known solution. I can experiment after the cert flight is done. That sounds like another thread in the Recovery section...
Did a little ground testing. Tried some at the BattlePark launch on Saturday. Didn't work out to well. I had stacked the rocket in the kitchen before taking it to the car. I had the small box with shear pins and assorted part there too. Guess what got forgotten? It was so cold few showed up an none of them had 4-40 shear pins either.
Went to my TAPs place today for some more testing and some mixing. I would have to say we are dedicated rocketeers! We were out in the yard ground testing in 17 deg weather while it snowed! I will say, it is much nicer setting up everything is his warm basement and just taking it outside to test than having to do everything out at the field.
Final result, 5g of FFFFg for the main chute and 3g of FFFFg for the apogee/drogue charge. That is using four 4-40 shear pins on the nosecone and two 4-40 pins on the av-bay to booster joint. We also loaded the upper payload with a d-bag and 10 ft. chute.
It's getting to the point where it's almost ready for the paint!
Went to my TAPs place today for some more testing and some mixing. I would have to say we are dedicated rocketeers! We were out in the yard ground testing in 17 deg weather while it snowed! I will say, it is much nicer setting up everything is his warm basement and just taking it outside to test than having to do everything out at the field.
Final result, 5g of FFFFg for the main chute and 3g of FFFFg for the apogee/drogue charge. That is using four 4-40 shear pins on the nosecone and two 4-40 pins on the av-bay to booster joint. We also loaded the upper payload with a d-bag and 10 ft. chute.
It's getting to the point where it's almost ready for the paint!
The only construction item still left is to drill and tap the hole for the forward rail button. Other than that, its ready for paint.
Here's a pic of the fin can. I coated the fillets that contained the 1/4" fiberglass strands with some epoxy that had West Systems 406 Colloidal Silica. That is mostly for aerodynamics and looks, mostly looks.
I also weighed the parts. The fin can came in at 17 lbs 15.4 oz, or 18 lbs.
The nose cone was 5.5 lbs.
The payload tube was 6.25 lbs, the shock cords and d-bag was about 2 lbs and I still need to weight the main chute.
I think everything is going to come in right about at 38 to 39 lbs without the motor. That is really close to the 40 lbs that Ken told me it would weigh when I bought the kit from him. Was there ever any doubt?
Here's a pic of the fin can. I coated the fillets that contained the 1/4" fiberglass strands with some epoxy that had West Systems 406 Colloidal Silica. That is mostly for aerodynamics and looks, mostly looks.
I also weighed the parts. The fin can came in at 17 lbs 15.4 oz, or 18 lbs.
The nose cone was 5.5 lbs.
The payload tube was 6.25 lbs, the shock cords and d-bag was about 2 lbs and I still need to weight the main chute.
I think everything is going to come in right about at 38 to 39 lbs without the motor. That is really close to the 40 lbs that Ken told me it would weigh when I bought the kit from him. Was there ever any doubt?
MaxQ
Tripoli 2747
....from another recent thread on the subject of pull pins.....
Please correct me if I am missing something here, but isn't this a newer version of the code? https://www.tripoli.org/LinkClick.asp...g=&tabid=185
In the above 7/31/2012 version it's here:
A-5 A rocket motor shall not be ignited by using:
a. A switch that uses mercury.
b. "Pressure roller" switches
From TRA's Safe Launch Practices dated 7/31/2013 https://www.tripoli.org/LinkClick.asp...Y=&tabid=326
4. A rocket motor shall not be ignited by a mercury switch or roller switch.
Originally Posted by MaxQ : So pull pins are NOT prohibited?
No - They don't have mercury and are not pressure roller switches.
Note that NFPA 1127 requires that all firing circuits be inhibited unless the rocket is in the launching position.
https://www.rocketryforum.com/showthread.php?122526-Did-Tripoli-ban-pull-pins
BTW: Nice build here....when is it flying? March ?
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I'm planning on the 27th of March. If Ken will be on-site on Friday. The Battle of the Rockets is Saturday so that will probably be too busy. If those don't work, then it will have to be Sunday.
jimzcatz
Boss, Carolina Rocket Mafia
That's the specific reason that I don't use charge wells in the bulkhead. I make small charges using centrifuge tubes and place them in the bottom if the airframe. And yes, pullpins are not allowed for staging and airstarts.
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MaxQ
Tripoli 2747
No pull pins for airstarts?
Unfortunately that would seem to cover what I was interested in doing...
I have a Xavien FIST that has a nice pull pin option for air starts on slower take off/scale rockets with outboards (like my Astrobee 1500 upscale) that would be perfect for a pull pin since I'm not sure a G switch would trigger the conventional air start - like G switches in my older GWiz unit. That GWiz would not trigger the air starts in my upscale Little Joe II.
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Didn't get much done the last few weekends, family matters were higher priority.
Anyway, it snowed today so the government said I couldn't go into work today. I got a little more done on the rocket.
First, I got some actual weights. Since you all like pics so much, here you go.
Booster section weighed in at 18 lbs.
The nose cone was at 5.5 lbs
the upper BT was just under 6.25 lbs
The shock cords and quick links were 1.4 lbs
The main chute and d-bag were 4.4 lbs
and the Av-bay was 5.35 lbs.
That all comes to 41 lbs.
I have most of the part weight corrected in the Open Rocket file, but it's still showing 42.3 lbs. I think that may be much closer to actual after I get it painted so I'm going with that for my sims.
Attached is the updated file.
Anyway, it snowed today so the government said I couldn't go into work today. I got a little more done on the rocket.
First, I got some actual weights. Since you all like pics so much, here you go.
Booster section weighed in at 18 lbs.
The nose cone was at 5.5 lbs
the upper BT was just under 6.25 lbs
The shock cords and quick links were 1.4 lbs
The main chute and d-bag were 4.4 lbs
and the Av-bay was 5.35 lbs.
That all comes to 41 lbs.
I have most of the part weight corrected in the Open Rocket file, but it's still showing 42.3 lbs. I think that may be much closer to actual after I get it painted so I'm going with that for my sims.
Attached is the updated file.
I did get some testing of the av-bay done. I had ground tested the rocket to determine the charge sizes. Now I just wanted to make sure the altimeters worked as advertised.
I taped up all the holes in the av-bay, used clay and tape to seal the shop vac over the last open vent port, attached some matches and simulated a flight with the shop vac.
I have a two second delay on the secondary apogee charge. I'm sure its good, but when you're waiting for it to go off, those two seconds seem like a long time.
Anyway, the matches all lit in the order expected and with the timing expected.
Next up is a test flight on a 4200 Ns EX L motor. Should get about 5K ft and give it a good shake down flight. That is if we can actually get a launch done at Battlepark. Weather and field conditions have kept us from flying since December. The next launch is March 14 & 15.
The cert flight is planned for March 27th.
I taped up all the holes in the av-bay, used clay and tape to seal the shop vac over the last open vent port, attached some matches and simulated a flight with the shop vac.
I have a two second delay on the secondary apogee charge. I'm sure its good, but when you're waiting for it to go off, those two seconds seem like a long time.
Anyway, the matches all lit in the order expected and with the timing expected.
Next up is a test flight on a 4200 Ns EX L motor. Should get about 5K ft and give it a good shake down flight. That is if we can actually get a launch done at Battlepark. Weather and field conditions have kept us from flying since December. The next launch is March 14 & 15.
The cert flight is planned for March 27th.
I thought about using as existing chute as the drogue, but decided to make one. I had ripstop left over from making the main. Here's the thread - Build Thread - 9 ft, 24 Gore, Semi-Elliptical Chute
Anyway, making a drogue from the same material as the main ensures they will match. Having matching chutes isn't really important, but it is my L3 cert. Besides, it's something else I can make.
So I decided on a Disk-Gap-Band chute. I got the information from the Recovery Systems Design Guide. The Disk-Gap-Band chute was used to drop the Viking lander on Mars. Mine will have a 24" Disk with 12 gores of alternating red and white.
Here's the page about the Disk-Gap-Band chute from the Recovery Systems Design Guide along with the first disk gore and band piece.
Here are the patterns I used to cut out the rip stop. I used heavy kraft paper. I would suggest using a wood pattern if the pieces are much larger then these. The paper works OK on smaller pieces
Here are the red pieces and a couple of white.
I worked on the Disk first. The rectangles were easiest. First I hemmed the upper and lower edges.
Sewed the pieced together to get the final band.
Here's the finished disk and the band. Now I just need to attach the shroud lines.
More pics when it's done.
Anyway, making a drogue from the same material as the main ensures they will match. Having matching chutes isn't really important, but it is my L3 cert. Besides, it's something else I can make.
So I decided on a Disk-Gap-Band chute. I got the information from the Recovery Systems Design Guide. The Disk-Gap-Band chute was used to drop the Viking lander on Mars. Mine will have a 24" Disk with 12 gores of alternating red and white.
Here's the page about the Disk-Gap-Band chute from the Recovery Systems Design Guide along with the first disk gore and band piece.
Here are the patterns I used to cut out the rip stop. I used heavy kraft paper. I would suggest using a wood pattern if the pieces are much larger then these. The paper works OK on smaller pieces
Here are the red pieces and a couple of white.
I worked on the Disk first. The rectangles were easiest. First I hemmed the upper and lower edges.
Sewed the pieced together to get the final band.
Here's the finished disk and the band. Now I just need to attach the shroud lines.
More pics when it's done.
I've been spoiled for quite a while. A friend gave me an explosion proof exhaust fan years ago. I used it to build a paint booth in the basement. I've been able to paint rockets year round.
I was able to get the nose cone painted in the booth. I put on two layers of primer, wet sanding with 400 grit in between. I used 600 grit after the first layer of metallic paint, and plan on using acrylic Future on the nose cone after the paint dries.
The rocket has finally pushed the limits of the spray booth. The booth is only 4 ft wide and the upper payload tube is a full 4 ft long and the lower tube is 5 ft long. Obviously it wouldn't fit in the booth. With the temps in the teens yesterday and even in the low 40s today, I couldn't paint outside.
My solution was to extend the spray booth with heavy mil plastic sheets.
Here's the booster hanging in the extended booth with it's first coat of primer. It was surprising how fast the over spray was sucked into the booth and the filters. This worked better than I had hoped.
The better half did mention being able to smell the paint in the house, but only a little bit. I'm sure it's much better then if I had just tried to paint in front of the booth without the extra plastic.
I'll post more pics when I get it finished.
I was able to get the nose cone painted in the booth. I put on two layers of primer, wet sanding with 400 grit in between. I used 600 grit after the first layer of metallic paint, and plan on using acrylic Future on the nose cone after the paint dries.
The rocket has finally pushed the limits of the spray booth. The booth is only 4 ft wide and the upper payload tube is a full 4 ft long and the lower tube is 5 ft long. Obviously it wouldn't fit in the booth. With the temps in the teens yesterday and even in the low 40s today, I couldn't paint outside.
My solution was to extend the spray booth with heavy mil plastic sheets.
Here's the booster hanging in the extended booth with it's first coat of primer. It was surprising how fast the over spray was sucked into the booth and the filters. This worked better than I had hoped.
The better half did mention being able to smell the paint in the house, but only a little bit. I'm sure it's much better then if I had just tried to paint in front of the booth without the extra plastic.
I'll post more pics when I get it finished.
So I got the drogue done.
I debated if I should use the 550 parachute cord or the 150 lb dacron line for shroud lines. I've use the dacron to make main chutes from golf umbrellas for a 10 lb rocket. They have worked perfectly. I decided to use the same lines and techniques on the drogue that I used on the main. After all, they'll be a matching pair then.
I also threaded the lines through the seams like I did on the main. I'm not sure that is required, probably overbuilding, but again, they are a matching pair. It also makes for a pretty heavy duty drogue chute. But then again, this is a L3 rocket.
Here's the finished chute. I used the same 1.5" nylon strap and 4000 lb D-ring that I used for the main chute.
Here's a detail of the riser with the D-Ring
The riser open so you can see how the shrouds were attached.
It turned out to be pretty light.
Now for some Nomex wraps to keep it looking good.
I debated if I should use the 550 parachute cord or the 150 lb dacron line for shroud lines. I've use the dacron to make main chutes from golf umbrellas for a 10 lb rocket. They have worked perfectly. I decided to use the same lines and techniques on the drogue that I used on the main. After all, they'll be a matching pair then.
I also threaded the lines through the seams like I did on the main. I'm not sure that is required, probably overbuilding, but again, they are a matching pair. It also makes for a pretty heavy duty drogue chute. But then again, this is a L3 rocket.
Here's the finished chute. I used the same 1.5" nylon strap and 4000 lb D-ring that I used for the main chute.
Here's a detail of the riser with the D-Ring
The riser open so you can see how the shrouds were attached.
It turned out to be pretty light.
Now for some Nomex wraps to keep it looking good.
I planned on doing a test flight this weekend on a research L1050, but it looks like rain this weekend.
Anyway, I ordered the motor and case. I'll be getting a Loki 76/6000 motor case and the M1882LW reload. Sims say it should reach 6384 ft. at about 500 mph.
Anyway, I ordered the motor and case. I'll be getting a Loki 76/6000 motor case and the M1882LW reload. Sims say it should reach 6384 ft. at about 500 mph.
JDcluster
Well-Known Member
Not quite same rocket as yours but;
My Mad Dog 6" did 9,900 ft at URRF last year on an 98 mm x 8,000 Ns EX M.
The rocket weighed 52 lbs on the pad.
Good Luck!
JD
My Mad Dog 6" did 9,900 ft at URRF last year on an 98 mm x 8,000 Ns EX M.
The rocket weighed 52 lbs on the pad.
Good Luck!
JD
That should be pretty close to what mine is. The sim for the M1882LW shows 53 lbs on the pad.
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