A View from Broadway

Half-A-size Monoboom Combat planes, ready to fly. Ken Burdick photo.

Half a Boom!

... is better than one

By Ken Burdick
November 2018

Also see: 1/2-A Monoboom building notes article from 2019

Yes Folks, it’s true.

If a little is good, then half is better? No, that can’t be it. Less is more? No, not that either.

It all started out innocently enough with a conversation between me and John Knoppi. I told him I had a new K&B  .15 drum rotor engine from 1972 and was going to build an FAI Monoboom for it. Before I could say “lemme outta here,” John had two Monoboom kits and an engine to trade for the new-in-the-box K&B. John is a prolific collector of engines and kits.

I built the full-size Monoboom, and all went well. It flew like only a Monoboom can. The nice part was because of the .15 and not a full-on .36, it was easy on my heart, but on F2D lines, it was a handful.

The full-size Monoboom, powered by a K&B .15. Original was designed by Mike Hoffelt for the monstrous Hoffelt .36. Ken Burdick photo.

Life goes on, but I was still impressed with the high performance of the bigboom.

Some ballplayers can’t resist a high fastball; I can’t resist a high-aspect wing.

Someplace in the shop, I had a set of the 1/2A Monoboom plans I had purchased from Baxter's plans, now owned and operated by Bobby Mears.

It took a while, but I found them in some long-discarded envelope placed where they would be safe -- you know. I looked at the skinny thing drawn there and scoffed. “No way” I thought. But being a bear of little brain, I set about to build an exact copy of it no matter what I thought I knew.

I built it to the plans in every detail, even if I disagreed with some of it. The elevator hinge was offered two ways. A complicated thing with bearings and a rod, or a flap hinge that you just drill a hole for and glue in. Guess which one I chose?

When it was done, I really liked the results, and set out to fly the tiny wing. I have only one 1/2A HP engine that the Buzz Man talked me into buying in 2000 or so. A black Fora “GRS” that just keeps getting faster with age. I run it on 35% nitro and it keeps up with the best of them. Having flown the bigboom, I was a bit wary of the takeoff. If you get it out of shape before it gets going, you will have your hands full and it’s game on.

I slowly pulled it out of the launcher while the Fora .049 was snorting and breathing fire.  The takeoff was perfect at dead level, but then it disappeared when I gave it some control input. I felt it behind me and gave it full down -- I found it doing super-tight outside loops about 180 degrees from where I last saw it.

Training the pilot in the subtleties of how to take it off took some time. But after a few flights to be able to do my regular F2D practice maneuvers, the tiny wing did them as well as any F2D ship I have flown.

What was even more amazing to me was that it didn’t slow down. The thing was literally beating the heck out of my rusty reflexes; fortunately if it got away I could just hold down and find it doing loops over my shoulder. The only issue besides my rust was stab flutter at level flight. Yep, the easy method was no bargin and the elevator was shaking like my hands after the initial flight.

Carried away

I was sold and as usual my enthusiasm took over all sense of propriety.

I got home and embarked on a plan to build more of them. I made a way-too-complicated excel spreadsheet to source parts, built three jigs to make parts and spent hours trying to get the pivot hinge to work, and unsuccessfully tried to use a carbon boom.  The CF boom can be made to work, but not drilled through the balsa trailing edge.

It was about this time that I discovered Tim Hobbins on Facebook. Hobbins Hobbies as it is known.

Tim builds primarily Vintage Diesel Combat combat wings. Laser cuts parts and -- had a listing for all three size Monoboom ribs. I sent away for 10 sets.

What, me worry?

The ribs from Tim got lost in the Canadian mail someplace. They were currently threating strike, so Tim quickly sent another to my Seattle address. I would be there in a week and all looked rosy.

When I got there and opened the package, my heart sank; somehow Tim’s coordinates created the right length and shape, but they were real tiny. about ¼” narrower than the plans. The perfectly made ribs sets were itty-bitty when placed next to the plans I had, so no room for a bladder tank.

The manufactured rib, above, and the actual plan size, below. Ken Burdick photo.

Running back to Saskatoon

Like the song says, this thing is “home grown, not made in Hong Kong.”

When I got back to B.C., two things happened. First there was a brown package from England waiting for me. Uh-oh, you guessed it, the original order from Tim Hobbins. Two months or so had gone bye and the original order of ribs finally showed up. The Canadian mail system had given new meaning to the term “snail mail.”

Great, now I have 20 sets of itty-bitty ribs. I did the next right thing, and sent Tim another payment, then let him know the ribs were too small compared to the plans. He wanted to make things right and insisted on making them to my specifications. I sent him the measurements from the plan set. The ribs are currently waiting for me in Seattle, where I will be in December. In the meantime, all the material for 10 models had arrived -- what to do?

I hate cutting out ribs -- just don’t like it -- yuck-o.

So, I began cutting out ribs, and while doing this, I also built up one of the small sets just to see how it might turn out. It has a bulged tank extender that allows the model to hold enough fuel. The thing flies perfectly only faster, if that’s possible -- how do I get myself into these things????

Prototype No. 2. Ken Burdick photo.

The thin airfoil might be perfect for the TeeDee event flown in the San Francisco area, but Half -A Combat has always been a love-hate relationship for me and TeeDees seemed to make it more complicated.

What I DO know is, large or small airfoil, these things fly better than any other wing I have flown. I’ll tinker with the idea more over the winter and see if I can get a version constructed more like the current F2D wings out there.

Meanwhile, I’ll still be building the “classic” Monoboom until I run out of wood.

-- Kennyb

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This page was upated Oct. 30, 2019