Modular Raven AvBay

[troj]

It's not really clear in the original picture, but I had in mind to glue in a short section of airframe tube into the bulkhead to act as a liner to prevent the gas path you're showing.

That's how I visualize it, as well.

-Kevin

 

[KevinDunn]

Thanks. I have a Raven and avbay coming from Wildman's Black Saturday, and I'm going to try making it modular using ideas from this thread.

 

[cwbullet]

That is a pretty cool design. I am gong to try a modular av bay.

 

[sodmeister]

Kevin ,for nice clean holes in Bluetube ,Phenolic and heavy LOC cardboard tubes ,a good quality(it makes a difference) bradpoint bit does either by hand or drill press.I like to back the hole with another scrap piece of tube or large dowel.

The bit in the first picture (straight cutter then spurs are the best)

Paul T

 

[o1d_dude]

Brad point bits on a drill press FTW.

Backing anything you drill through is key to avoiding tear out.

 

[troj]

Brad point bits on a drill press FTW.

Backing anything you drill through is key to avoiding tear out.

With Blue Tube, it's not the backside that's the problem -- it's the top. The bits like to crab it and pull it out.

-Kevin

 

[BobCox]

There are a lot of good ideas in this thread. I'm glad I haven't committed to any mounting for my Raven.

 

[patelldp]

I recently posted some pictures to my 2-stage Formula 54 thread that are applicable here. I mounted the Raven and its 38mm Av-Bay in the nosecone of that rocket and essentially made a universal mount that could be applied to any altimeter bay.

First picture is of the three pieces involved: cone with 38mm tube, t-nut in CR next to tube, and the Raven with G10 bulkhead attached:

Second picture is of the Raven and G10 bulkhead from the other side:

Third is a picture of the two pieces going together:

Last picture is of how the altimeter bay is retained:

This assembly can be placed in any rocket that has a 38mm tube installed in the nosecone or coupler. I have complete access to both sides of the Raven Av-Bay for dual deploy, airstarts, or staging. The retaining is simple and can be done with a standard bolt if a recovery point is not needed.

 

[troj]

This assembly can be placed in any rocket that has a 38mm tube installed in the nosecone or coupler. I have complete access to both sides of the Raven Av-Bay for dual deploy, airstarts, or staging. The retaining is simple and can be done with a standard bolt if a recovery point is not needed.

I like it!

I think this and the Power Perch provide ways to make mounting a Raven a very quick and easy thing to do -- less fiddling at the field is always a good thing.

-Kevin

 

[KevinDunn]

I mounted the Raven and its 38mm Av-Bay in the nosecone of that rocket and essentially made a universal mount that could be applied to any altimeter bay.

I like this a lot. I assume there is a vent hole for the altimeter and that since the avbay is mounted off center, the vent hole in the nosecone lines up with one in the avbay coupler? Is the avbay off-center to accomodate the blind nut, or to put the magnetic switch close to one side, or both? This mounting seems as elegant as the Featherweight avbay itself.

 

[Adrian A]

That is nice. I like what you did with the bolt. How unbalanced laterally is the rocket when you roll it on a table? I could imagine that the weight of the bolt might offset some or all of the weight of the av-bay.

This makes me realize that I would only need to produce a 54mm passive bulkhead as a converter to 54mm. Hmmm...

 

[patelldp]

I like this a lot. I assume there is a vent hole for the altimeter and that since the avbay is mounted off center, the vent hole in the nosecone lines up with one in the avbay coupler?

The vent hole will be through the body tube, through the nosecone shoulder, and into the 38mm tube and coupler.

Is the avbay off-center to accomodate the blind nut, or to put the magnetic switch close to one side, or both? This mounting seems as elegant as the Featherweight avbay itself.

The av-bay is off center to accommodate the magnetic switch. My original mock-up had the 38mm tube centered, but that didn't allow enough meat around the perimeter for an eyebolt (preferred over epoxying on a piece of Kevlar). The magnetic switch also didn't work very well in this set up and turning the altimeter off was a struggle.

 

[patelldp]

That is nice. I like what you did with the bolt. How unbalanced laterally is the rocket when you roll it on a table? I could imagine that the weight of the bolt might offset some or all of the weight of the av-bay.

This makes me realize that I would only need to produce a 54mm passive bulkhead as a converter to 54mm. Hmmm...

I have not rolled it on the table, but I would certainly assume that it will cause some lateral unbalance.

A 54mm passive bulkhead would be amazing! Being able to get a 54mm Passive Bulkhead will greatly simplify my next planned project which will mount my Raven and Big Red Bee in a 54mm tube within a 76mm cone. As of right now I was planning a custom job, but this would greatly simplify my set up.

 

[Adrian A]

I have not rolled it on the table, but I would certainly assume that it will cause some lateral unbalance.

A 54mm passive bulkhead would be amazing! Being able to get a 54mm Passive Bulkhead will greatly simplify my next planned project which will mount my Raven and Big Red Bee in a 54mm tube within a 76mm cone. As of right now I was planning a custom job, but this would greatly simplify my set up.

If it's a BRB simple transmitter, it can already fit alongside the Raven inside a 29mm or 38mm av-bay if you take off the BRB's battery and programming connectors.

The av-bay is off center to accommodate the magnetic switch. My original mock-up had the 38mm tube centered, but that didn't allow enough meat around the perimeter for an eyebolt (preferred over epoxying on a piece of Kevlar). The magnetic switch also didn't work very well in this set up and turning the altimeter off was a struggle.

If the bolt was made of non-stainless steel, I could see how that could interfere with the mag switch in certain orientations of the av-bay, but I'm surprised that the distance alone would be enough to cause a problem. Are you sure the magnet was oriented correctly?

 

[Adrian A]

A 54mm passive bulkhead would be amazing! Being able to get a 54mm Passive Bulkhead will greatly simplify my next planned project which will mount my Raven and Big Red Bee in a 54mm tube within a 76mm cone. As of right now I was planning a custom job, but this would greatly simplify my set up.

It looks like you already made the equivalent of a passive bulkhead once (your black circle), so are you wanting to avoid making another one? All the passive bulkhead is that comes in an av-bay kit is a drilled piece of fiberglass with some printing on it.

 

[patelldp]

If it's a BRB simple transmitter, it can already fit alongside the Raven inside a 29mm or 38mm av-bay if you take off the BRB's battery and programming connectors.



If the bolt was made of non-stainless steel, I could see how that could interfere with the mag switch in certain orientations of the av-bay, but I'm surprised that the distance alone would be enough to cause a problem. Are you sure the magnet was oriented correctly?

I was able to turn the unit on without much issue, however getting the correct orientation of the magnet was an issue when trying to power the unit down. Could have been stupidity on my part, but I fixed it by offsetting the tube.

It looks like you already made the equivalent of a passive bulkhead once (your black circle), so are you wanting to avoid making another one? All the passive bulkhead is that comes in an av-bay kit is a drilled piece of fiberglass with some printing on it.

I have a bit of OCD when it comes to building these things. If there was an available 54mm passive bulkhead to clean up my arrangement, I'd buy it. Also, for the 76mm rocket, the 54mm altimeter bay tube will be centered in the cone.

 

[Adrian A]

I have a bit of OCD when it comes to building these things. If there was an available 54mm passive bulkhead to clean up my arrangement, I'd buy it. Also, for the 76mm rocket, the 54mm altimeter bay tube will be centered in the cone.

Along these lines, it looks like you could remove the Featherweight passive bulkhead from your setup in the photos above if you want to, since your black version would do that job on its own.

 

[patelldp]

Along these lines, it looks like you could remove the Featherweight passive bulkhead from your setup in the photos above if you want to, since your black version would do that job on its own.

The black bulkhead has a 1/4" hole in the center, unfortunately. It came with the kit and was meant to hold an eyebolt if the bulkhead was just simply epoxied in.

Next time I am home I will work something out that will look better.

 

[Zephhyr]

What works best for me is to drill the initial hole with a very small drill (1/8 or smaller) step up a couple sizes at a time till you get to around 7/16, then use a step drill to make the final hole.

These are the step drills I use, always get a clean hole this way.
https://www.harborfreight.com/2-pie...oated-high-speed-steel-step-drills-96275.html

With Blue Tube, it's not the backside that's the problem -- it's the top. The bits like to crab it and pull it out.

-Kevin