So the club I belong to is signed up for a flying competition in two weeks, and I've been nominated to participate in the flour bombing. Surely some of you have done this a few times before, can anyone offer any tips? I've never done it before. Seems as though you have to stick to a pre-determined speed (set by the competitor, min 1.3Vso), and altitude (300ft), with points being detracted for variation to speed and altitude and of course distance from target. I'll be flying a 172.

What would you say, 10* flaps, 70kts? I would assume the slower the better?

Thanks in advance. Should be fun regardless.

The math seems a little complicated. I think that is why WWII bombers used the Norton Bomb Sight. Dive bombers and Cobra gunship pilots have always used the steepest dive angle they could live with. I don't know the math, but the cone of fire is a circle if we are going straight down. The cone of fire elongates more the shallower the dive angle.

So, you have to go with a level 300'? Are there any old Vietnam air cav scout torques (crew chief and door gunner in the back of the loach) here? They have lots of practice putting grenades in bunkers and spider holes.

You're going 100 feet every second at 70 mph. If you can figure out how long it would take your flour bomb to fall say 300', let's guess 3 seconds, at 300' AGL & 70 mph you'd wanna drop it 300' before the target. This assumes you know the descent time & doesn't account for any decay in forward velocity- both big variables.
I guess this is why most flour bombers just go by the seat of their pants.

I'm not sure if the ballistics would be similar to a watermelon...

In all seriousness, we got pretty good at dropping those melons over the years from as high as 1100' AGL. The key is to have the same pilot/bombardier/plane combination, fly every pass at the same speed/altitude/configuration, and evaluate your results and adjust as necessary. With the same guy in the right seat, I was able to hit within a 50 ft circle from 1100' consistently. From 300', I bet we could have gotten within a 10' circle pretty easily. It takes a few runs, and if you can cheat with a spotter on the ground, that is huge help. Windage is determined by the pilot, elevation is determined by the bombardier, unless you are comfortable cheating, in which case the bombardier has a lot of leeway by throwing the bag. If you aren't cheating, you aren't trying, right?

We used the GPS breadcrumbs, zoomed the map all the way in, and we could see if our track was off by 5-10 feet, so lateral adjustments were easy for the pilot. I was always flying, so I'm not sure what trigger my bombardier was using, but he'd adjust his drop timing based on the last run.

We used 20* of flaps and 80 MPH indicated, which at the altitude we were operating at was probably around 92-94 MPH TAS.

Lots of fun to be had here, but its easy to drop the airplane to fly the flour sack, so make sure you're watching the airplane first.

They have a bomb drop contest at the West Coast Cub fly-in every year in Lompoc. It's been going on for 31 years, and nobody has ever gotten a bomb in the barrel.

This is from one of the slowest airplanes on the planet at 200', and everyone gets two chances.

It's harder than it looks.

We just made a couple of flour bombing runs at the EAA Golden West Fly In in Marysville, CA - from an Ercoupe at 300' AGL & 70 mph we failed miserably. The math is pretty easy to work out but this game is really more art than science. Trajectory drop is the term that describes the arc a projectile follows as it travels downrange. There is no data to describe a paper bag with a small mass of flour and we found that its just as likely to get blown backwards by the initial prop blast as follow any kind of predictable ballistic path.

If you get a few practice runs you may be able to get a sense of how your bombs drop from your aircraft and then factor in the current conditions, but if not you'll just have to go with your gut. Good fun either way!

I've only dabbled with air drops a little bit, but what about the old technique of pitching the payload out when the target disappears under the nose? Seems to work pretty well for air drops.

-DP

denalipilot wrote:I've only dabbled with air drops a little bit, but what about the old technique of pitching the payload out when the target disappears under the nose? Seems to work pretty well for air drops.

-DP

I'm going to have to agree with DP. I know that ice cream sandwiches fall almost straight down. I wouldn't think a flour bomb would be too much different.

You threw a perfectly good ice cream sandwich out of a plane? What were you thinking?

From watching hundreds of drops at the Cub flyin over the years (the bombs we use have streamers attached), the bombs stop traveling forward almost immediately and fall straight down. Of course, there's usually a 20kt wind, so the bombs travel backwards at 20 KTS until they hit. Those who get close drop 20-30 feet past the barrel because of the ever present wind in Lompoc.

I'll have to consult with my bombardier (he's 12). I'm sure he factored in this years 15-20kt crosswind into his mathematical model.

Normally, I rely on the Mark I eyeball method and a tap-on-the-shoulder of the drop mechanism which usually results in an adequate outcome.

Here is this years first-run at the Poplar Grove Airport Fly-In.

https://youtu.be/KMZA-UuVFo8

A better question...how did I get so lucky to have the GoPro mounted on the step at the correct angle to capture the hit? Much more complicated (or luck) - take your pick.

Barnstormer wrote:You threw a perfectly good ice cream sandwich out of a plane? What were you thinking?

They were for kids below. So it's usually 30 of them. No damage from impact which is why I continue to use them.

We've done flour bombing at the Reed fly-in most years. Everyone has their own method, but it's largely a "TLGE" method (that looks good enough).

My most accurate bombardier was a young kid, about 15, who had never flown before. Since I hadn't flown my airplane from the right seat recently, he was in the right seat but there's no opening window on that side. I flew at about 80 mph approximately 100' off the deck with 10 flaps. He opened the door a few inches, leaned into the window to see, and dropped when it made sense to him. He missed the target by only about 10', so that was pretty good.

On the next run, using the same "technique" if you can call it that, he got a little closer. But the next couple were farther away, and by that time we were out of flour bombs.

I suppose if someone was serious about winning flour bomb contests, he could construct a bomb-sight similar to what was used in the Doolittle raid on Tokyo. But it's hard for me to put "serious" and "flour bomb contests" in the same sentence.

Cary

A1Skinner wrote:

Barnstormer wrote:You threw a perfectly good ice cream sandwich out of a plane? What were you thinking?

They were for kids below. So it's usually 30 of them. No damage from impact which is why I continue to use them.

That's cool. What kind of gathering/event is it for?

Barnstormer wrote:

A1Skinner wrote:

Barnstormer wrote:You threw a perfectly good ice cream sandwich out of a plane? What were you thinking?

They were for kids below. So it's usually 30 of them. No damage from impact which is why I continue to use them.

That's cool. What kind of gathering/event is it for?

It for a Christian horse camp that we are part of. I think there is 8 weeks of camp all different ages. They love the ice cream drops, and I love doing it. Everybody wins!

I have participated in 3 flour bombings at Nanaimo Airport. The first time nobody wanted to go with me in the 172 at first then big Gerry asked to be the bomber. At the time I was 300 and Gerry was an honest 350. While we at the pilots meeting I noticed some money action going on in the background. The boys were placing side bets as to whether my little 172 would even get airborne. We got airborne and I won $10. We were down wind and Gerry says what do I do. I told him I had no blinking idea, this was all new to me. I said lets put half flap down and open the door and see what happens. Well a little left rudder and a little extra power and we were good. The next problem was big Gerry could not get swung around to make the drop so off with the shoulder harness and loosen the lap belt and he was good to go. In front of us was a Flybaby and I wondered how he was going to do this with single pilot and mid wing design. No problem, get over the target , knife edge the wing and throw. I thought that seemed to work good but I had not talked this over with Gerry so I thought straight and level at 100' might be best. The drop was middle of the pack but not a winner. I asked Gerry if he heard anything about minimum altitudes during the pilots meeting and he said NO. OK lets get this thing down closer to the target, we both agreed a gentle touch and go on the grass right at the target would work best. Everything went good until we hit 25'. That is when the judges sitting in the lawn chairs started running and the noise in the headsets from the tower got real loud and annoying. We did not see were our flour landed but we thought we had won because all the people were running to congratulate us when we were taxing in. As I shut down the words I heard were somewhat confusing. Your disqualified, banned, kicked out of here were reapeated time and time again. I asked why and they said i flew too low. I asked where during the pilots meeting were we told the minimum altitude. The looks I got were the true definition of a blank stare. All turned out well but we still did not win.
The next year the first thing on the pilots instructions were NOT BELOW 100'. That year my wife wanted to do the bombing. Well we were are all set up on a long final at 100' and over the water of the inlet and I told my wife to open the door and get ready to throw the bag. WHAT DO YOU MEAN OPEN THE DOOR!! We basically passed the target when the door was opened for a second and the bag sent out, not a close shot. Next pass I ask her to open the door earlier and she says NO. I said why not. I don't want to fall in the water. I think to myself, at 100 ' would I want fall and hit water or dirt. I just grinned and said Ken fly the plane , you will not win this discussion. The third year my friend Pete wanted to do the bombing. The organizers decided to change things a bit and filled the bags with grass clippings from the recently mowed strip because someone forgot to buy the flour. We were allowed 3 passes this time because of the different content. I explained the shoulder harness thing to Pete and off we went. We approached the target Pete threw the bag out and then out the door he went. Well that's what I thought happened and it scared the crap out of me big time. What actually happened was Pete is much smaller that Gerry and with the belts loosened right off Pete could get right out there and see where the package landed. When he rolled back in he said " are you alright, you look really white". I told him all was good and we will review the flight later. The next 2 passes were similar but with the added excitement of flying through a horrendous down pour on short final on the last round and doing a little spacing for a Dash 8 inbound. The Dash 8 won the spot landing contest and we won the grass bombing contest. When the guys found out Pete was retired RCMP you would not believe the amount of times he was asked where he learned to throw grass out of a plane so accurately. His standard answer was " I thought for sure one of you local boys would win". Flour bombing can be a great adventure and a whole lot of fun. Fly Safe