Tubes and High G forces

[debk]

I am curious how high acceleration can effect a tube. 

I know kind of a weird question.  What I want to do is put some sort of vacuum tube payload in one of my rockets and fly it.  I am thinking of a simple transmitter, just transmitting a tone.  Of course the transmitter will have to be battery powered, and the lighter I can make it the better.  The rocket I will most likely use will have a payload section 6in in diameter and 18in long, but it can be made longer.  I would expect the rocket to have an apogee of around 6000 to 8000ft, and a maximun acceleration of 10Gs.  The maximum velocity should be under mach 1.

I can not find much data on tubes and acceleration.  Should the tubes be mounted in the the direction of flight or perpendicular to the direction of flight?  Are there special tubes designed for higher g environments. 

Any comments or suggestion would be welcome

Debra

 

[Doc B]

If you look in a tube manual for tubes with military numbers they were often used in aircraft applications. You will sometimes find shock ratings in the Special Ratings & Performance Data section. One example is the 6201 (mil spec 12AT7), rated at 600G.

 

[2wo]

Hi Deb, Nice to meet you. Here is a link to one seller. Look at some of the ones with attached leads. They are small, light and don't require a lot of voltage or power. Some tubes of this type were made for Russian ICBM's so they should feel right at home.

http://stores.ebay.com/SOVCOM/Tubes-/_i.html?_fsub=3&_sid=29574324&_trksid=p4634.c0.m322

I would like to learn more about the sort of Rockets you are flying, Is there a website?...John 

 

[JC]

I wonder if it is still possible to find any of the little triodes once used in hearing aids?  IIRC, they used leads rather than pins and sockets, allowing for easier shock mounting.

They were at one time adapted for use in proximity fuses for 5" Navy guns in WW2, so they had to withstand muzzle velocity and centrifugal force.  I don't recall the actual number of Gs, but it was significant, as you would imagine.

 

[debk]

Hi Deb, Nice to meet you. Here is a link to one seller. Look at some of the ones with attached leads. They are small, light and don't require a lot of voltage or power. Some tubes of this type were made for Russian ICBM's so they should feel right at home.

http://stores.ebay.com/SOVCOM/Tubes-/_i.html?_fsub=3&_sid=29574324&_trksid=p4634.c0.m322

I would like to learn more about the sort of Rockets you are flying, Is there a website?...John   

Likewise, nice to meet you also.

The website for the rockets is www.tripoli.org.  It is an international organization with prefectures all around the world.

Deb

 

[Grainger49]

I wonder if it is still possible to find any of the little triodes once used in hearing aids?  IIRC, they used leads rather than pins and sockets, allowing for easier shock mounting.  .  .  . 

If you mean Nuvistors they are scarce.  The ones I have seen are large enough they wouldn't fit in a behind the ear hearing aid.  I suppose it was a box, like a transistor radio with an ear plug.

 

[JC]

Actually, Grainger, I was thinking more along the lines of the smaller examples here:

http://www.hearingaidmuseum.com/gallery/General_Info/GenInfoVacuumTube/info/generalinfo-vacuumtube.htm

I'm not sure specifically which types, but some of them were used in 5" Naval shells for little transmitters and receivers; after being fired, they sent out their signal, and when they received their own signal back, it activated the fuse.  Prior to that, the fuses were on timers, making it next to impossible to hit anything faster than a boat.

 

[Cary]

The Nike Hercules missile used tiny vacuum tubes in the guidance section, there are about 8-10 plug in modules with 2-3 tube each. Near San Francisco there is an actual Nike Missile Site that you can tour. In the Warhead Building is one of the boards on display. The Nike system was an all vacuum tube system. The radars are still used today at Edwards AFB and a few other places that I can not talk about.

Before drones became popular a program that I worked on placed a video camera in a 6" cannon shell. It's purpose was for spotting targets. It worked well, the Army decided not to fund it.

 

[Grainger49]

This is what I had in mind as a high G force tube.  The body is metal, rugged, the leads are out of focus but it is next to a standard 9 pin socket for size comparison.  It is a single triode.

 

[debk]

Thanks for the information. First I will have to come up with a circuit that I want to fly.  If I have time to get it done I may fly it this summer if not next year for sure

Deb

 

[2wo]

Grab a copy of "The Radio Amateur's handbook, mid 50's. Easy to come by, their even at the Library...John

 

[JC]

debk, you may also want to research  Dr. James Van Allen, and his study of the Northern Lights; he used what he called "rockoons", small rockets launched from weather balloons after they had reached maximum altitude.  I know that he was able to capture a great deal of EM radiation in his experiments, using tiny electronics packages he designed to fly on his rockoons; what I do not know for sure is whether this work was before he received a sample of the prototype transistors to fool around with, but I'm thinking it was.

Some of the rockets in your link look enormous compared to the ones I launched back when!

 

[jrebman]

Hi Deb,

Yes, as Jim said, these rockets sound like i n a different league altogether than the Estes rockets I used to build and fly back in the early 70s.  Sounds like a blast -- no pun intended.

Good luck with your project and let us know how it turns out.

-- Jim

 

[debk]

These are  quite bigger than Estes.  The rocket I am looking to fly this in is about 12ft long and 6in in diameter, should weigh in at about 80lbs or so with the payload.  At this time I plan on working on this over the winter and fly it next flying season.

My big rocket project for this year is a 10 foot long 4in diameter all carbon fiber rocket that I hope will go about 40,000ft.

I flew this rocket last year on a much faster burning motor and it did about 26,000ft,  hit mach 2.5, and pulled just over 75G's.

Much higher performance than what I intend to fly the tube transmitter in.

Thanks everyone for your suggestions.  I will post more about this when I start working on it

Debra

 

[jrebman]

<lol> That's some serious rockets there!  Very impressive!

I'm going to build/rebuild my trio (Paramour IIs and FP III+) using some birch core, carbon fiber plates that are 0.125" thick.  Do you do the layup on the tubes yourself or buy them pre-fab?

-- Jim