What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

explosive bolts

brian

brian

Well Known Member
I decided some time ago to not use the standard tipup canopy hinge pins and to use AN4 bolts instead, as popping the canopy in flight has never been tested (that I know of) and I decided it was all too iffy to bother with. Plus the linkage would interfere with my tight avionics placements. But, if I could replace those AN4 bolts with explosive bolts, that would give me the best of both worlds.


I know some military aircraft use explosive bolts in some applications. Is it possible to get explosive bolts anywhere, like in AN4 sizes?

thanks,
brian
 
LOL....only someone from NH would think of something like this.

Currently in California but working my way back. Dang, I miss that place.
 
brian said:
I decided some time ago to not use the standard tipup canopy hinge pins and to use AN4 bolts instead, as popping the canopy in flight has never been tested (that I know of) and I decided it was all too iffy to bother with. Plus the linkage would interfere with my tight avionics placements. But, if I could replace those AN4 bolts with explosive bolts, that would give me the best of both worlds.


I know some military aircraft use explosive bolts in some applications. Is it possible to get explosive bolts anywhere, like in AN4 sizes?

thanks,
brian
Click to expand...

How much money do you have? :rolleyes: (NASA was/is the primary user) :eek:
 
Pyrotechnic Separation....

You've actually got a good question, but the truth of the matter is that explosive bolts really aren't - bolts, that is. "Pyrotechnic separation" is usually accomplished with nuts that split, guillotine cutters (for cable bundles), primer cord which actually cuts the metal - or, in the rare case, a bolt with a weakened shank or head that is fractured. But what the general term "explosive bolt" conjurs up in the average mind really doesn't exist.

Now, if you WERE to come up with a design that could explosively separate your canopy, you'd probably spend way more than the airplane is worth (literally) doing the engineering for the one-of-a-kind device. Then you'd have to worry about always wearing nomex in the cockpit, so that if you fired it, you wouldn't ignite.

Good quesiton....but I didn't say you'd like th answer.... :rolleyes:

Paul
 
By the way. You and your passenger are inside when those things go off. The first few times JSF did egress testing with a dummy. The dummy's head was completely destroyed. I would not want to find out that type of information the first and potentially the last time you activate those devices.
 
BATF

Ironflight said:
.....
Now, if you WERE to come up with a design that could explosively separate your canopy, you'd probably spend way more than the airplane is worth (literally) doing the engineering for the one-of-a-kind device. Then you'd have to worry about always wearing nomex in the cockpit, so that if you fired it, you wouldn't ignite.

Good quesiton....but I didn't say you'd like th answer.... :rolleyes:

Paul
Click to expand...

As well as lots of discussions with the BATF.... :D

gil in Tucson - all of our explosive devices were assembled in bunkers, even the little ones.... and the test procedures can be tricky.... :) The pilots didn't like it when the missiles didn't separate from the plane... :D
 
oh well

Hmmmmm - so much for that idea. I had pictured a nice little AN4 bolt that just went *pop* enough to break it. Sounds like there's MUCH more to it than that, which I guess is why I never heard of any being for sale. On second thought, I suppose there would be little difference between one of them and a blasting cap, which you can't exactly go down to the hardware store and buy a box of. Thanks for all the feedback.
brian
 
Jettisoning things...

I wish I had a simple way that I could jettison all the wheel pants off if I were about to make a forced, off-field landing.
Seems like it may help in keeping the plane from flipping over from the pants getting hung-up in grass, weeds. etc......and roll better.

...just one of those wild thoughts I guess. ;)
 
When I was a purchasing agent for a phamacutial company an engineer wanted me to get a quote on a device to read pressure from the inside of a power mixing tank and send a signal to exploding bolts to blow the hatch off the side, thereby releasing pressure before the tank exploded. His estimated cost $100,000. After careful consideration I went to the hardware store and bought 6 nylon 1/4-20 bolts and handed them to him. After two weeks of study he came back and said, "That will work too." Actual cost $1.00.
 
Last edited:
Most miliatry canopies in ejection seat equiped airframes have a cordite like charge in the plexi to shatter the canopy prior to the seat going up the rails....

It's been done .... it bet it would be colorful :)
 
Ha ha he he, BOOM!

You can get a T-handle with flex cable and mount it anywhere to pull the pins. Safer than explosives. :rolleyes:

Are you going to buy some parachutes (about $900-$1200 each). If not don't bother.
 
gmcjetpilot said:
Are you going to buy some parachutes (about $900-$1200 each). If not don't bother.
Click to expand...
Also the jettison capability is pretty much muted by the lift struts. Yeah, you *could* just reach up and yank on the struts and hope the ball joints release, but in the mean time you've just lost 1000 feet. :rolleyes:
 
Jamie said:
Also the jettison capability is pretty much muted by the lift struts. Yeah, you *could* just reach up and yank on the struts and hope the ball joints release, but in the mean time you've just lost 1000 feet. :rolleyes:
Click to expand...
That's just one reason I don't have the struts. I still have the original hold up strut that is disconnected when the canopy is closed.
I've also converted others back to the original design for acro pilots.
 
LOL

Geico266 said:
.... His estimated cost $100,000. After careful consideration I went to the hardware store and bought 6 nylon 1/4-20 bolts and handed them to him. After two weeks of study he came back and said, "That will work too." Actual cost $1.00.
Click to expand...
I got quite a chuckle from this story.
 
Bolts

If I dont stand corrected... either a helicopter or a design idea for a certain helicopter has explosive rotor head bolts and ejection seats...(hopefully the bolts work!!!)
Gutsy test pilot!
Best
Brian
 
brian said:
... the linkage would interfere with my tight avionics placements. But, if I could replace those AN4 bolts with explosive bolts, that would give me the best of both worlds...
Click to expand...
Brian,

Try this solution. You still can release the canopy, if you need to and it gets the handle out of the panel.



 
Yikes, I guess that's another good reason why they wear helmets!

Hostage46 said:
Most miliatry canopies in ejection seat equiped airframes have a cordite like charge in the plexi to shatter the canopy prior to the seat going up the rails....

It's been done .... it bet it would be colorful :)
Click to expand...
 
brianwallis said:
If I dont stand corrected... either a helicopter or a design idea for a certain helicopter has explosive rotor head bolts and ejection seats...(hopefully the bolts work!!!)
Gutsy test pilot!
Best
Brian
Click to expand...
I believe that was the Commanche, which was canceled.
 
N941WR said:
Brian,

Try this solution. You still can release the canopy, if you need to and it gets the handle out of the panel.
Click to expand...
Thanks for the tip, Bill

brian
 
Jamie said:
Also the jettison capability is pretty much muted by the lift struts. Yeah, you *could* just reach up and yank on the struts and hope the ball joints release, but in the mean time you've just lost 1000 feet. :rolleyes:
Click to expand...
I don't think those struts would make any difference. At speeds as low as 60 mph (or lower) the canopy would yank those pistons right out of the struts so quickly you would never think they were attached. All it would take is getting some air up under the front of the tip-up.

There is the crux of the hole thing, I doubt you could lift the front of the tip-up in flight, struts or no struts.
 
N941WR said:
Brian,

Try this solution. You still can release the canopy, if you need to and it gets the handle out of the panel.



Click to expand...

What's keeping the pins in place if this mod is made? Doesn't the spring on the rod handle keep the pins from releasing or backing out?
Thanks,
Tony
 
Tony Rome said:
What's keeping the pins in place if this mod is made? Doesn't the spring on the rod handle keep the pins from releasing or backing out?
Thanks,
Tony
Click to expand...

No, there is no spring. The T handle goes slightly over center. In 500 hours it hasn't moved. Don't forget, if you think you want to jettison the canopy, you need to cut slots for the hinges. I did not cut the slots and have only used that contraption during my build to install and remove the canopy frame for test fitting and to rivet the forward skin.
 
Primer cord on the landing would be great. Blow the gear off before a water landing. I think about this each time I cross some of the ocean and the Great Lakes.
As for tip up canopy removed I left the pull mechanism out of the panel and use a cord handing down with a t handle to rank. Works well when removing the canopy for service.
The canopy only goes up about two inches in flight if it is not latched.
 
You must log in or register to reply here.
Back
Top