38mm 3D printed sleds Have finally arrived!

The wait is over!

The compact 38mm altimeter sled is designed for a Raven, Stratologger, or Hi Alt 45, and a 400mAh Sparkfun lipo battery.

There is a separate 9V battery sled which can be mounted below the 38mm sled if you prefer not to use the Lipo battery.

The sleds are made for #8-32 all thread with 1in spacing, and weigh a mere 12g.

The cost for each sled is $9.95

https://www.etsy.com/listing/182690154/38mm-altimeter-sled
https://www.etsy.com/listing/182692896/38mm-9v-battery-sled?ref=listing-shop-header-0

Awesome. They look great.

That my friend is a work of art. Any chance you can mount other altimeters on it?

The missile-works versions will be up on their site in a few days.

I have longer "Blank" sleds in the works which will allow you to mount anything you want.

An extended 5 inch long version of the sleds may also be coming, with a wider variety of mounting holes which caters to the larger altimeters out there. Arts, MAWD, Adept 22, Eggtimer/tracker, certain GPS modules, and telemetrum will all likely be included.

Those are very nice. Might be just the excuse I need to make another Sparkfun order too.

Landru said:

The missile-works versions will be up on their site in a few days.

I have longer "Blank" sleds in the works which will allow you to mount anything you want.

An extended 5 inch long version of the sleds may also be coming, with a wider variety of mounting holes which caters to the larger altimeters out there. Arts, MAWD, Adept 22, Eggtimer/tracker, certain GPS modules, and telemetrum will all likely be included.

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[cough]RRC3[/cough]

Damn. My order just shipped or I would add one of these.

Performance nut said:

[cough]RRC3[/cough]

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https://www.missileworks.com/store/#!/~/category/id=8599330&offset=4&sort=normal

No 38mm...op:

A few PMs later and some 38s are added (box had not left the building yet). More toys!:horse:

what are the dimensions on the lipo bay? Just wondering if it will fit one of these:

https://www.hobbyking.com/hobbyking/store/__23135__Turnigy_nano_tech_180mah_2S_25_40C_Lipo_Pack.html

It will not fit one of those.

The lipo battery holder is approximately 5x25x35mm

I have one of these sitting in front of me currently and it really is amazing.

BLKKROW said:

I have one of these sitting in front of me currently and it really is amazing.

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You better be at ARG because I want to see it.

jus_rockets said:

You better be at ARG because I want to see it.

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I was going to show up on Sunday I will not be flying.

I can certainly bring the 54mm and 38mm sled I have.

Awesome looking, It's almost perfect for my needs...I need one with the lipo for the Stratologger but with a mount for the featherweight magnetic switch...any chance you will have this as an option?

mpitfield said:

Awesome looking, It's almost perfect for my needs...I need one with the lipo for the Stratologger but with a mount for the featherweight magnetic switch...any chance you will have this as an option?

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You can use the space for the turn switch and mount the magnetic switch there.

BLKKROW said:

You can use the space for the turn switch and mount the magnetic switch there.

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I understand that looks to be a possibility however the one consistent word of advice on using the magnetic switch is to make sure it's security mounted. Therefore a specific mount is ideal and anything other is a work around, and I am not a fan of working around issues unless I have to, hence the request! If it's not on the drawing board then I understand as you can't manufacturer these things for every scenario, however the space looks like it is just about the right size and ideal location for the switch so it may be an easy change...don't ask don't get.

mpitfield said:

I understand that looks to be a possibility however the one consistent word of advice on using the magnetic switch is to make sure it's security mounted. Therefore a specific mount is ideal and anything other is a work around, and I am not a fan of working around issues unless I have to, hence the request! If it's not on the drawing board then I understand as you can't manufacturer these things for every scenario, however the space looks like it is just about the right size and ideal location for the switch so it may be an easy change...don't ask don't get.

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How should the switch be oriented and what are the hole spacings? I may be able to fit it in.

Landru said:

How should the switch be oriented and what are the hole spacings? I may be able to fit it in.

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It appears that the switch can be mounted in any number of ways and the magnet is to be waived from one long side to the other, so mounting it long side vertically should be fine. There may be a reason to mount the 2 holes up or down based on the wiring but I will leave that to your discretion. I have 8 of the switches and it looks like there are differences in the overall dimensions I am guessing based on hand productions, however the published dimensions are close enough. The hard part to measure are the holes so I have measured them from center to center in relation to one another. The 2 holes on one end are mostly at equal distance from the sides however because the boards vary in size including being square it is difficult to measure them in relation to the other 1. The attached picture is crude but my best guess. I think so long as the diameter of the holes is less than the maximum diameter there will be some play on the mounting.

View attachment 166291

Check your diameter on the hole sizes. 1.1"?

accpool said:

Check your diameter on the hole sizes. 1.1"?

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Thanks, I saw that and meant to correct and forgot, obviously the decimal needs to move over to the left 1 so .11"

Landru said:

How should the switch be oriented and what are the hole spacings? I may be able to fit it in.

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I too like the magnetic switch. I'm planning to make something to lock in the hole that will have a plate with mounting holes on it. If you could make an clean add on of somesort that would fit nicely, I for one would buy it.

Got my second order from Andrew. So now I have two 808 camera shrouds as well as a 54mm, a 75mm and a dual 98mm 3d printed sled. These things are awesome. Great time savers too.

Prior to seeing these, I was in the process of building a modular sled system that would fit in all my different diameter rockets. Because of the intense planning and actual construction time, as well as trying to accommodate my existing avbay's, it was taking a lot of time and effort and I was falling behind schedule. Andrew's design simplifies my task and the sleds are lighter too.

The 75mm single altimeter sled will also be used in my smaller 98mm rockets. The switch is still close enough to the avbay wall to be easily accessible. The 98mm dual altimeter sled is for my larger too-expensive-to-lose designs

I have also decided to simplify sled and/or altimeter changeover by incorporating Doghouse Rocketry's excellent Teflon color-coded wiring with locking connectors. I attach the male ends to all my altimeters using White for switches, Brown for Apogee charges and Orange for Main charges. The wires with female ends get permanently attached to charge cups, and power switches. I will also use some Red/White wires and locking connectors in the future to make batteries easier to disconnect.

After receiving my 3 sleds from Landru I found that although my Perfectflite Stratologger fit perfectly, that my older Perfectflite MiniAlt/WD units do not, as they are longer. The holes on the ends of both altimeters are similar but there was no way to support the MiniAlt/WD with only two holes for mounting.

So I made an adapter plate. I cut a piece of .062" G10 15/16" wide x 3.5" long and made a platform for the longer altimeter. The G10 then received holes for mounting to the sled as well as offset holes and standoffs for the longer altimeter.

This can be done for all other long altimeters. The only thing to verify on the smaller 54mm avbays is that the top of the altimeter will clear the avbay tubing should it be higher than the integrated switch mount. In my case the only way around this was to eliminate the standoffs below the adapter plate and use shorter mounting screws for the adapter plate so it only adds 1/16" of height to the instalation. If you don't shorten the screws, the two above the battery compartment will protrude in or worse foul a battery if one is installed possiblly stripping the screw holes or (unlikely) puncture the battery. This is not a problem for 75mm (shown in photos) and 98mm sleds as there is lots of room. I would think this would be a problem on the 38mm sled.

But I have suggested to Andrew that he lengthen the sleds by a tad in the future so longer altimeters can be accommodated. Being an earlier adopter hurts! :bang:

Landru said:

The missile-works versions will be up on their site in a few days.

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This took more than a few days (sorry, I was sick last week). FINALLY got these prepped and ready, and both 9V and Li-Ion sled versions are in the cart.

The 38mm Li-Ion sleds also include the mating JST PH series connector, which you can covert to a wire-end harness for the RRC2+ or clamp directly into the battery compression terminals of the RRC3.

Yaay - bought one

Edit: FYI the 400mAH Lipo battery is out of stock at the moment but I spoke to Sparkfun customer service on the phone (really helpful guy FYI) and they have more stock arriving April 1st.

Zebedee said:

Yaay - bought one

Edit: FYI the 400mAH Lipo battery is out of stock at the moment but I spoke to Sparkfun customer service on the phone (really helpful guy FYI) and they have more stock arriving April 1st.

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Good to know they are restocking these soon!
I'm going to buy a few more for my personal sleds.

For those of you who are interested in blank sleds (of all sizes), how blank do you want? No battery holder? No switch mount?

a blank sled with a battery holder would be cool.