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-   -   Bomb bay for flour bombs (https://vansairforce.net/community/showthread.php?t=80528)

DanH 12-30-2011 11:27 AM

Be careful with the belly hole.....huge carbon monoxide source down there. Can you make it absolutely airtight?

Tom Martin 12-30-2011 12:42 PM

Dan
I was thinking the same thing about the CO gas. At the very least it should be tested inflight with a CO monitor under various flight conditions.

LynolA 12-30-2011 01:52 PM

Quote:

Originally Posted by DanH (Post 611248)
Be careful with the belly hole.....huge carbon monoxide source down there. Can you make it absolutely airtight?

Positive pressure in the cabin can help with that. Just have your vents open.

LynolA 12-30-2011 01:59 PM

Quote:

Originally Posted by N24YW (Post 611026)
This should be large enough to hold a couple of roles of TP for marking the foes grass runway during simulated bombing runs. This is being installed on a RV 7 being built at a secret aircraft factory in Iowa.

Jim Knight
Burlington Iowa
RV 6 500 hourts

Looks pretty nice. How do the belly doors open? We see the inside cams, but what rotates these from the outside of the box? Do you have additional pics?

LynolA 12-30-2011 02:15 PM

Ideas are flowing...
 
These are all great ideas. Thanks for all the input. I settling in on an idea that requires a rotary servo. Anyone know were to find a servo and a controller? The ones I see online are for RC airplanes that interface into a RC receiver. I don't want to have to plug the servo into a receiver and have to deal with a transmitter. I need a controller that can accept a switch input (i.e., bombs away) and command a servo to rotate the 180 degrees. Any ideas?

fatherson 12-30-2011 02:40 PM

Quote:

Originally Posted by LynolA (Post 611293)
I need a controller that can accept a switch input (i.e., bombs away) and command a servo to rotate the 180 degrees. Any ideas?

You need a "servo tester" like this one. There are commercial ones too.

--
Stephen

DanH 12-30-2011 03:37 PM

Quote:

Originally Posted by LynolA (Post 611284)
Positive pressure in the cabin can help with that. Just have your vents open.

I'd bet a beer that opening the cabin vents won't stop airflow up through a hole in the belly.

However, I'm not saying you can't do it. The design in the photo is clever, in that it has an interior lid. It should be easy to build very good seals under that lid so that the chamber acts like an airlock. Just keep the lid closed and latched in flight.

The really clever here will work out a bombsight.

Brantel 12-30-2011 03:45 PM

I built one out of an Arduino based uController for a few bucks. Works with all model plane servos.

Quote:

Originally Posted by LynolA (Post 611293)
These are all great ideas. Thanks for all the input. I settling in on an idea that requires a rotary servo. Anyone know were to find a servo and a controller? The ones I see online are for RC airplanes that interface into a RC receiver. I don't want to have to plug the servo into a receiver and have to deal with a transmitter. I need a controller that can accept a switch input (i.e., bombs away) and command a servo to rotate the 180 degrees. Any ideas?



Quote:

Originally Posted by fatherson (Post 611299)
You need a "servo tester" like this one. There are commercial ones too.

--
Stephen


fatherson 12-30-2011 04:22 PM

Quote:

Originally Posted by Brantel (Post 611322)
I built one out of an Arduino based uController for a few bucks. Works with all model plane servos.

Yeah, my 14-yo son built something similar with an Arduino Uno, but it controlled 6 servos and a motor for a small robot, so I think the parts were about $50.

--
Stephen

jpallist 12-30-2011 04:23 PM

Flour bombing through photo port in RV-6
 
An interesting discussion. Seven years ago I constructed a camera port in the baggage floor behind the copilot's seat in my RV-6... it is a standard 4" Van's type inspection port hole in the skin with backing plate and aligned with an identical 4" hole in the baggage floor skin... both with cover plates which attach with screws and nutplates. (When in use, I made a clear lexan coverplate for the outer hole to shoot through). The camera port worked great: I built a mount to fit my digital SLR to the port, used a long cable shutter release and routed the video output to a PDA mounted near the panel so I could see what I was shooting.... but, that's a different story.

A few years later, the opportunity for four bombing presented itself... and I already had a port!! Some PVC pipe and plumbing adapters from the hardware store and I had a ready-made flour-bombing set up. Turns out that this location and my plumbing puts the port under slight vacuum so no problem with exhaust fumes (although a rubber sewer pipe cap was rigged to the top of the PVC pipe just to be safe and to cut down on the noise). I found a black plastic reducer fitting that nicely fits the hole in the skin and attaches with screws into the recessed nutplates. It sticks out slightly into the slipstream, which may help account for the vacuum (venturi effect). And with a bit of sanding, it mates nicely with a 3.25" OD X 28" long piece of PVC pipe that can be inserted from inside the airplane.. I found that I could load the bomb tube up with a dozen separately bagged flour bags and rigged a release consisting of a U-shaped wire with the ends extending through parallel holes near the base of the tube and with a piece of cord attached to the U-end as a release cord. To keep the flour (+ some sand for extra weight and accuracy) from working their way out, I use a circular piece of cardboard at the bottom of the load, immediately above the pins.

If someone could tell me how to post some photos, I will do so.

Cheers, John P.


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