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Bomb bay for flour bombs

LynolA

Member
At some fly-in's there is an event for flour bombing. This works pretty well with airplanes that have open cockpits or side windows that open. A lot more difficult when you have an RV with a tip-up or sliding canopy! I've been searching for something online, but found nothing. So I've been sketching out several ideas from simple to complex. I think I would enjoy being able to particpate in this activity with an RV, but never seen it done. Anyone have any ideas or seen or built a little bomb bay into their RV?
 
No but ...

Tom Martin devised a pumpkin drop mechanism for his wing tip. I'm sure he would have ideas for a centerline external stores release system.

Bob Axsom
 
Bomb bay

We have an elderly gentleman in our state who loved to drop candy to children from his RV. He constructed a tube that was behind the copilot seat and exited straight down thru the belly just behind the copilot seat. He would grab a hand full of candy and drop it into the tube.

A similar system might work for you.

I do not endorse this; I am merely the reporter of facts.
 
We have an elderly gentleman in our state who loved to drop candy to children from his RV. He constructed a tube that was behind the copilot seat and exited straight down thru the belly just behind the copilot seat. He would grab a hand full of candy and drop it into the tube.

A similar system might work for you.

I do not endorse this; I am merely the reporter of facts.

wonder if that tube was used for some other purpose?? :eek:
 
Quote:
Originally Posted by RV8R999
wonder if that tube was used for some other purpose??




JATO rocket connection point.
Short field take off, no problem.
 
The tube solution is similar to what is used for spreading ashes. The big difference is the tube needs to exit as far back as possible. But that is all probably moot in this use case.
 
I have given this much thought over the years but haven't tried building anything.

My thought was a "bomb rack" that could attached to the tiedown hard point and use some type of relay to drop the flower sack (Or pumpkin) and would be removable.

My thinking is that you will have to limit your top speed to keep from ripping the sack open.
 
I have given a lot of thought into that one as well. I think I have a good idea for a spring driven rotary dispenser with 3 bays and servo actuated release pin. Imagine the bags loaded like a revolver cylinder with the bottom open so that they drop out as they come around. The big killer is the mount. Am thinking about making a bomb rack like Arnold's (AR-5 fame and travel pod designer) wing pod.

Way down the road, gotta get flying for a while first. Have already made the mold for the wing leading edge though, had to do that before paint.
 
Two Liter Bomb

A number of years ago I saw an RV-4 with a bomb rack. A simple solenoid release was attached to an inspection plate. The bomb was a two liter soda bottle fitted with fins. Unfortunately, I didn't get any pictures. No report on accuracy of the system. Perhaps someone here can re-engineer a similar system.

Scott A. Jordan
N733JJ
 
The structure and mechanics for an underwing device isn't too hard. An electrical release would be most convenient. Trick is how to be sure you never have an accidental release. How is that done in military designs?
 
Dropping objects

Dan, in the military we did have dropped objects, objects that would not fall off but were armed, and switch errors that produced undesirable results. That's with multi-million dollar systems, scientists and engineers, trained arming crews, and a big budget.

In fact, if you want to spice up this thread, let's invite other military types to share the fun times they had!

Me first: On a bombing range when a new major in the unit showed up. He was next to use the targets, so he began to set his switches for his anticipated rockets. Unfortunately, although he was over the range, he accidentally fired rockets off range and set a farm on fire!

Careful all!

Remember:

Sec. 91.15 ? Dropping objects.
No pilot in command of a civil aircraft may allow any object to be dropped from that aircraft in flight that creates a hazard to persons or property. However, this section does not prohibit the dropping of any object if reasonable precautions are taken to avoid injury or damage to persons or property.

Sec. 91.13 ? Careless or reckless operation.
(a) Aircraft operations for the purpose of air navigation. No person may operate an aircraft in a careless or reckless manner so as to endanger the life or property of another.
 
Flour or TP?

It would be sweet just to be able to launch a roll of TP....
I've always wanted to try that exercise. I'm thinking a coffee can size recess in the belly in the baggage comp just behind my seat (RV-3), with an interior slider cover plate operated with a push/pull cable.
 
My fellow Vern :)

Regarding the TP: Years ago I used to watch a Luscombe do this very often from a near by location.

The gouge: Start with a new roll, and unroll about 50 feet but hold it all around the roll. Toss it out the window and watch it unfurl to it's 2000-3000' length. Split S thru it and see how many times it could be cut before reaching an unsafe altitude.

Of course, the Luscombe would occasionally land with a length of evidence hung on the tail wheel! Makes it hard to deny what just happened!
 
Bomb racks

The structure and mechanics for an underwing device isn't too hard. An electrical release would be most convenient. Trick is how to be sure you never have an accidental release. How is that done in military designs?

There were 2 methods used during my time for bomb rack operation. The older designs used mechanically over-centered spring arms that opened with a huge electrical solenoid.
The newer versions are the impulse cartridge fired racks. The charge when fired physically unlock the rack and the ejector piston kicks the bomb away from the aircraft.

As for controlling the electrical portion of the firing circuit, depending on which aircraft we're discussing, there are several steps the pilot had to accomplish before he could even attempt a release. The one common safety feature all the aircraft I ever worked had, is the landing gear had to be up and locked.
 
Dan, in the military we did have dropped objects,

Isnt that the purpose of much military flying???:rolleyes:

Oh, yes, this is about accidentally dropped objects.

That's with multi-million dollar systems, scientists and engineers, trained arming crews, and a big budget.

No wonder you had accidents, with all that help.

We are homebuilders, we can do better:D
 
I'd go off the fuse, centerline. Secure flour bomb by wrapping in safety wire, drill hole in bottom of fuse, run wire up through hole, secure wire. May want to rivet a reinforcing plate at the hole to support weight and drag of bomb.

Vise grips could secure the wire for simplicity if located near bombardier.

Or, if you're willing to drill the hole larger, tie off a loop in the wire and cotter pin it. Run a line to the cotter pin for remote release if too far from the bombardier.

Seems simple and low tech so cheap and hard to screw up???


Oh, and sounds very fun too. Another benefit of experimentals, we can drill holes randomly in our aircraft just for the fun of it!:D
 
The structure and mechanics for an underwing device isn't too hard. An electrical release would be most convenient. Trick is how to be sure you never have an accidental release. How is that done in military designs?

You wouldn't believe the amount of rigorous training and detailed procedures and inspections which accompany the proper installation, maintenance and loading of ordnance - and the Ordnance Men (Ordies we call them) take great pride in their work.

Each aircraft ordnance delivery system has unique features but in essence they all rely on a series of "fire breaks" or systems which all must function for the cartridge to fire and release the ordnance. Most racks have to be armed externally, then in the cockpit there will most likely be a master arm panel and then a selector for the specific rack and ordnance to be used - some do this in software others via switches. Additionally the launch parameters (airspeed, altitude, and a host of others) for the specific ordnance must be met or a software inhibit will prevent launching the weapon (at least in my former aircraft). Then the Weapon Release switch will have a cover over it. Even with all of that it is still possible to screw it up - it has been done.
 
ok, here you go, an externally mounted, electrically operated deployment device. The item to be launched is pushed on to the "spear" The spear pivots on the bolt that you see at the leading edge. The electrical device is a solenoid from the hatch back of a jeep Cherokee. Any trunk door opener could be made to work. As you apply power a pin pulls in releasing the spear to pivot. There is a stop that allows the pivot to just go aft of 90 degree degrees down.
In action, one minute you can see the pumpkin going along for the ride on your wing tip the next it is gone! I made this rig for the 2010 pumpkin dropping contest at Courtland 9A4. I had two tries (requires two flights and a ground crew to reload if you do not want to shut down).
On the first run I had an embarrassing case of premature pumqulation and I missed the airport! On the second run I made a respectful launch that at least came close to the target (outhouse)
The exercise was a lark but it truly gave me an appreciation for the work of the navigators and bombardiers of years past. Hitting something from the air is not as easy as one would think.
 
ok, here you go, an externally mounted, electrically operated deployment device. The item to be launched is pushed on to the "spear"

I can see a pumpkin gap developing. Someone starts with one. The next guy has two loaded...then four...or six or eight.
 
The one common safety feature all the aircraft I ever worked had, is the landing gear had to be up and locked.

Oh, well, in that case, let's talk about retracts!

Has anyone ever . . . [nevermind, ducking behind something for protection :D]

--
Stephen
 
...
The exercise was a lark but it truly gave me an appreciation for the work of the navigators and bombardiers of years past. Hitting something from the air is not as easy as one would think...

I was thinking about the targeting system on the drive into work this morning.

Do you?

A) Lob them in
B) Drop it from straight and level
C) Dive bomb

If you select C, do you add dive brakes and a siren, similar to a Stutka?

Oh, well, in that case, let's talk about retracts!

Has anyone ever . . . [nevermind, ducking behind something for protection :D]

--
Stephen
Simple answer, yes. Use the search, you will find some pictures.
 
Gear inspection door

Downloadfromdroid122911271.jpg

Downloadfromdroid122911266.jpg

IMG_2153.jpg

IMG_2154.jpg

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
 
Last edited:
ok, here you go, an externally mounted, electrically operated deployment device. The item to be launched is pushed on to the "spear" The spear pivots on the bolt that you see at the leading edge. The electrical device is a solenoid from the hatch back of a jeep Cherokee. Any trunk door opener could be made to work. As you apply power a pin pulls in releasing the spear to pivot. There is a stop that allows the pivot to just go aft of 90 degree degrees down.
In action, one minute you can see the pumpkin going along for the ride on your wing tip the next it is gone! I made this rig for the 2010 pumpkin dropping contest at Courtland 9A4. I had two tries (requires two flights and a ground crew to reload if you do not want to shut down).
On the first run I had an embarrassing case of premature pumqulation and I missed the airport! On the second run I made a respectful launch that at least came close to the target (outhouse)
The exercise was a lark but it truly gave me an appreciation for the work of the navigators and bombardiers of years past. Hitting something from the air is not as easy as one would think.

That is brilliant! I love it!
 
Beware of Holloween flights.......

There are so many things that this conjures up in my mind, most of which in some way include a mid air collision with a witch..............

That poor pumpkin seems to say it all with the expression:eek:

img0265j.jpg
 
Bomb bay

Jim Knight,
Your bomb bay photo has inspired me! Great winter project. Restricted to only a TP size and weight function, it should be easy to fabricate and install, not add more than a few ounces to the a/c, fit easily between the belly longerons, have no negative impact on other missions, and offer great fun for solo or group flights. Thanks for the inspiration!
 
Jim Knight,
Your bomb bay photo has inspired me! Great winter project. Restricted to only a TP size and weight function, it should be easy to fabricate and install, not add more than a few ounces to the a/c, fit easily between the belly longerons, have no negative impact on other missions, and offer great fun for solo or group flights. Thanks for the inspiration!

Why do I suddenly envision a couple dozen empty beer cans showering down on the target?
 
Be careful with the belly hole.....huge carbon monoxide source down there. Can you make it absolutely airtight?
 
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.
 
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?
 
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?
 
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.
 
I built one out of an Arduino based uController for a few bucks. Works with all model plane servos.

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?



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

--
Stephen
 
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
 
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.
 
Somewhere, in a dark corner of a basement in a windowless building, a DHS Web-bot is beginning to stir..... :)
 
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. ... 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.
I can help you post the photos, I'll PM you.
Both these ideas are great. I can see dropping one or several flour bombs at at time. I take it the cardboard divider leaves the airplane with the flour bomb. Nice multi-load concept, pretty simple and removable. That fits my criteria. The plus is multiple use for camera platform too. Will you share your camera adapter plate details too? I think several of us are interested in you video set up too. What video output to what PDA?
 
Let's just say I was contemplating this a year or two ago, you know, an external store for extra toilet paper in case one gets caught in the boonies in need...

TP%252520Bomb.JPG


I was going to attach it to several of the screws on the bell crank access cover. Hadn't gotten as far as how to deploy said rolls, but I was thinking a single bowden cable going under all three. Pull 4", deploy one, pull another 4", second one, etc. Put a spring of some sort on top of each roll. Hmmm.
 
Good discussion, we were wondering about the intricacies of a hatch in the RV.

TP out the door would not always completely unroll?. Ended up prepping each roll with masking tape on the first 5 feet or so, then rolling them back up. Grasping the tape as the roll goes out the door insures a completely unrolled streamer hanging in the sky for all kinds of fun.

Spreading Ashes was also problematic at first, some of the ash always ended up back in the cabin? joke was The Dearly Departed didn?t want to get out. A PVC pipe out into the slip stream did the trick after that, although some ash has bone fragments which can hang up.

pk
 
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.
Here's the Pics of John's Installation:
DSC01532.JPG


DSC01529.JPG


DSC01535.JPG


DSC01524.JPG


DSC01525.JPG


DSC01531.JPG


DSC01526.JPG


DSC01527.JPG


DSC01528.JPG
 
How about using the hard points under the wings where the tie downs are. Plenty strong enough. W/elec. solenoid release systems you could have both sides available for drops. Also, storage pods for bear spray, in Alaska.
 
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.

... here is John's video hardware pic and comment:
Attached is a low res. photo of the FlyJacket that mates with the old IPAQ's and turns it into a video monitor. Also in the same photo is a DigiSnap, which is an electronic remote control for various digital cameras. Figured these might be of interest if you are wanting to do low-cost aerial photography with an RV.
DSC01538.JPG
 
Specs on a flour bomb

What is the best bag and weight for a flour bomb? Is there a spec with a max or min, does each contest set its own rule, or is it all an ad hoc exercise - the bigger the better? If you are mixing flour and sand (sand for deadweight), what volume ratio? Sand may be somewhat cheaper, maybe, but why not just a bigger bag and more flour? What's the story, you bomber pilots?
 
What is the best bag and weight for a flour bomb? Is there a spec with a max or min, does each contest set its own rule, or is it all an ad hoc exercise - the bigger the better? If you are mixing flour and sand (sand for deadweight), what volume ratio? Sand may be somewhat cheaper, maybe, but why not just a bigger bag and more flour? What's the story, you bomber pilots?

I would think flour is better because it blows away in the wind where sand will require a more intensive cleanup.

I've been contemplating this for the last couple of years and my best thought would be to fashion a fiberglass pod that would attach to the underside of the wing screwed into the platenuts that hold one of the inspection plates. The door would be spring loaded and use an RC servo which can be remotely triggered from the cockpit or even a hidden buddy on the ground. Figure one per wing gives you two drops per flight or even a single unit with two doors so you only need one servo. Each unit is self contained with the servo so you just remove them when after you've won the contest.
 
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