LOC DoorKnob HED DD build

Sorry to hijack your thread... what's the difference between plug and bottom? I thoughts both were for tapping blind holes.

Ari.

Chris, can you post some pics of the inside of your nose cone set-up with the altimeter installed?

There's a picture of the altimeter tray on post #17. I'm still waiting for the magnetic switch to show up so I can finish it. Once it's done I'll epoxy it to the backside of the bulkhead.


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iter said:

Sorry to hijack your thread... what's the difference between plug and bottom? I thoughts both were for tapping blind holes.

Ari.

Click to expand...

Bottoming taps finish a threaded hole to have the threads go all the way to the bottom of the hole. The plug tap has a little taper, more tan the bottoming tap, but not as much as a tapered tap that starts holes easier.

Adrian

Back to our regularly scheduled program...

I received a magnetic switch and cable cutter from Bob at Aerocon Systems. I got the switch mounted to the tray last night. I was looking at how I'd like to mount the wiring since there aren't any solder tabs on the board. I decided to pick up some solder lugs similar to the one pictured below. The lugs will be sandwiched between two 4-40 nuts on the back side of the switch. There's a nice little electronics shop right across the street from my work that makes it easy to find stuff like this.



I've also been sanding the primer on the nose cone. I roughed up the NC before I sprayed it with adhesion promoter, then I hit it with primer. Well, I probably shouldn't have roughed it up quite so much so I had a bit of sanding to do. I think it's under control now. I need to fill the seam with some spot putty and then I can start painting.

I also ordered some custom vinyl from Mark at StickerShock. Everything seems to be falling into place.

I hit the NC and booster with another coat of primer on Saturday. I let it dry until Monday morning to make sure it was really cured. I sanded the NC with 400 grit dry yesterday and did the same to the booster this morning. It's looking ready for the color coats now.

In other news I finished up the altimeter tray this morning and tacked it to the bulkhead with CA. I'll add some epoxy fillets tonight. These aren't the best pictures, but they get the point across.

ChrisAttebery said:

I hit the NC and booster with another coat of primer on Saturday. I let it dry until Monday morning to make sure it was really cured. I sanded the NC with 400 grit dry yesterday and did the same to the booster this morning. It's looking ready for the color coats now.

In other news I finished up the altimeter tray this morning and tacked it to the bulkhead with CA. I'll add some epoxy fillets tonight. These aren't the best pictures, but they get the point across.

View attachment 180121

View attachment 180122

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Is that a magnetic switch? How does it work?

I don't want to be the bearer of bad news but a epoxied AV tray will not stay glued to the bulkhead, all three of my glued on AV trays have broken off epoxy and all.

When the nose cone comes to the end of the shock cord no matter how soft it seemed to eject or not? I don't know; :confused2: all I know is every AV bay came back separated from the bulkhead.


I will post a pic when I get home, of what I do now that has worked so far.


TA

Kehoes23 said:

Is that a magnetic switch? How does it work?

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With magents? duh!

jk


TA

Yes it is. You hook up the VDD IN and GND from your battery to the swtich and the VDD OUT and GND from the switch to the altimeter. When you pass a magnet past the switch it turns on. Pass the magnet over it again and it turns off.

https://shop.featherweightaltimeters.com/product.sc?productId=33

Kehoes23 said:

Is that a magnetic switch? How does it work?

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Interesting. John Coker has been using a similar design in his rockets without a problem. What kind of epoxy are you using?

In the worst case scenario I'll have to redesign the tray and include some kind of positive retention. I could always machine a bracket to attach the tray with the U-Bolt, but I was trying to keep it light and simple. I'll attempt to fly it as is and if I have a problem I'll have 2 months to get it right before the next launch.

thobin said:

I don't want to be the bearer of bad news but a epoxied AV tray will not stay glued to the bulkhead, all three of my glued on AV trays have broken off epoxy and all.

When the nose cone comes to the end of the shock cord no matter how soft it seemed to eject or not? I don't know; :confused2: all I know is every AV bay came back separated from the bulkhead.


I will post a pic when I get home, of what I do now that has worked so far.


TA

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Well I hope it works, I sure haven't had any success with it. I used Bob smith 5 min or 15 min epoxy I think.

I use the eye bolt thorough to the AV plate and with a washer lock it down that way I can take it off and add it to a different size AV bulkhead and rocket.

TA

That's a very clean design. Like I said maybe I'll machine a bracket and new tray after the first flight.


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thobin said:

With magents? duh!

jk


TA

Click to expand...

Hahahahaha

ChrisAttebery said:

Yes it is. You hook up the VDD IN and GND from your battery to the swtich and the VDD OUT and GND from the switch to the altimeter. When you pass a magnet past the switch it turns on. Pass the magnet over it again and it turns off.

https://shop.featherweightaltimeters.com/product.sc?productId=33

Click to expand...

Never used one, so I was not sure how one works, thanks for the no wiseass reply. Haha

Well, thobin beat me to it.

Kehoes23 said:

Never used one, so I was not sure how one works, thanks for the no wiseass reply. Haha

Click to expand...

ChrisAttebery said:

I got the holes and slots cut into the nose cone base:
View attachment 177360

I epoxied the T nuts into the centering ring and installed the hardware on the bulk plate:
View attachment 177361


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Looks really nice!

Thanks Bob!

You use a rare earth maginet that is supplied with the switch, you pass the maginet over the switch and one of the componets senses the field and electronically switches on the power. The documentation claims a range of one inch but I have found it to be a bit more, almost 2 inches

It has one small flaw is that that it has a small constant draw of power even when off so you need to disconnect it after use.

They work pretty great I will buy more of them for sure, its nice to not to drill more holes or line up stuff.


TA

Kehoes23 said:

Never used one, so I was not sure how one works, thanks for the no wiseass reply. Haha

Click to expand...

Sorry couldn't help it, I should have added how they work to my wiseass comment.


TA

It draws 3 micro amps in standby mode. It's a really small flaw.

thobin said:

It has one small flaw is that that it has a small constant draw of power even when off so you need to disconnect it after use.


TA

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I've been busy today. I woke up and got the recovery system assembled, built a 2 gram ejection charge, and re-installed the altimeter. I used 2x 3/8" making tape strips to hold the nose on. I took the rocket out back and tested the ejection charge to make sure it was strong enough. After that I applied the decals on the nose and masked and painted the second color on the booster section.

[YOUTUBE]Iwrrmp-UYGw[/YOUTUBE]

Ground test videos are always entertaining. Things go boom. But a vacuum cleaner? How high did the altimeter think you went?

Ari.

Looking forward to seeing this one fly. Are you going to do L1/L2 in one day at TCC next weekend?

You know Ari, I forgot to check.

No. I'm just going to go for L1 this weekend. If we have time maybe I'll take the L2 written test.

I bought an I455 VMAX for the maiden. I'm going to use the altimeter in MAIN only mode without the line cutter. I'm going to use the motor as a back up.

timro said:

Looking forward to seeing this one fly. Are you going to do L1/L2 in one day at TCC next weekend?

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I was able to get my L1 re-cert completed today. I had a problem getting the altimeter armed. Unfortunately it looks like my magnetic switch died this week. So, I took it out of the loop and used the twist and tape method to arm the altimeter. After that little fiasco everything else worked as planned. The flight was nice and straight and the rocket had a great whistle after the motor burned out. The RRC2+ beeped out 993', a little short of the 1133' that Open Rocket predicted. If I add a transition to the base of the rocket as Tim from Apogee suggested to use in RockSim for stubby rockets the simulation shows 959'.

Good job! Congratulations.

Ari.

ChrisAttebery said:

I was able to get my L1 re-cert completed today. I had a problem getting the altimeter armed. Unfortunately it looks like my magnetic switch died this week. So, I took it out of the loop and used the twist and tape method to arm the altimeter. After that little fiasco everything else worked as planned. The flight was nice and straight and the rocket had a great whistle after the motor burned out. The RRC2+ beeped out 993', a little short of the 1133' that Open Rocket predicted. If I add a transition to the base of the rocket as Tim from Apogee suggested to use in RockSim for stubby rockets the simulation shows 959'.

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Congrats on the L1! So what happen to the mag switch? How long have you had it? I'm trying to wrap my head around what could have happened to it, was shorted out some how? Thats a bummer dude at least and best of all you still got you LVL 1.



TA

Nice flight and congrats on the L1!