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Scale 25% Krier Kraft build, a tribute to grampa.

Bipeguy03

150cc
WHERE THE IDEA CAME FROM

Well, I've been itching to build for awhile because as much as I love my PAU ARFs nothing compares to the feeling of flying a plane you created from a box of stick. I had fun rebuilding my Pitts but again, it was a rebuild.

Now I have been considering the Hostetler 35% Pitts, but after a late night kitchen table talk with my dad I now have a different idea.

Dad has been wanting another bigger airplane, but he isn't the kind of guy to get an Extra or Edge he likes to be different. So sitting with him at the table that night looking at what was a available I remembered seeing the Seagull Models Bucker Jungmeister at the Sig booth at Toledo last year. As we looked over the pictures and specs dad made a comment that he liked the Bucker because it reminded him of Grampa's Krier Kraft and the lightbulb in my head went off.

THE STORY

1971 was the year, grampa Mick (short for our last name) just got out of the Air Force after his voluntary second tour in Vietnam. He moved from Massachusetts to Ohio for work after him and grandma separated and settled in. That winter dad came out to live with him and grampa who had been building models since he was a kid in the 30s decided to get started in the hobby again. During the following years, grampa Mick and dad built and flew to many airplanes to count.

As the 70s grew to a close, and dad now 18, had a fiancé and wasn't flying RC as much grampa started getting into giant scale airplanes after joining the IMAA. One of the first planes he built was a sport scale model of a little known full scale aerobatic Biplane designed by Hal Krier.

ENTER THE KRIER KRAFT ACRO-MASTER

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Grampa ordered a set of Flying Models Magazine "King Kong Krier" plans and went to town changing some aspects to make the model have the proper outline. He shortened the nose, removed the Bucker type hump in the turtle deck, made the belly skinnier, reduced the forward rake in the landing gear, changed the shape of the tail to look like the early rendition of the full scale, and reshaped the wingtips as well as stretch them 2 inches to get to the proper scale span of 71".


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He fabricated everything on his Krier with the exception of the pilot, engine, wheels and radio equipment. He even made his own fiberglass fuel tank. The landing gear was made from piano wire and made to have functioning bungees in the scale locations.

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The Krier's finished weight was 18 pounds, covered with Sig Koverall and painted with dope. It had a Quadra-Aero Q35 for power, and probably it's most unique feature was functioning boost tabs on all control surfaces allowing for use of STANDARD size servos. Keep in mind that standard servos of the late 70s and early 80s only had 30-40 oz of torque!

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The canopy was made out of pieces of other larger canopies and flat clear plastic stock, and all of the pen striping was painted on by reverse masking.

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The headphone jack next to the power switch was the ignition kill, putting the plug in the jack shorted the magneto to ground killing the engine. Gampa Mick did this to all of his gassers. Grampa built a few giant scale airplanes including a Hostetler Skybolt (which we still have) and a large Stinson Reliant.

He had and flew the Krier Kraft until the day he passed away in March of 1988 less than a month before my first birthday. My dad flew it a hand full of time afterward but not anywhere near as much as grampa. One day a guy approached him about buying it, and dad just starting a new business and with 2 young kids (me and my older sister) he decided to let it go.

Grampa's Krier I'm sure is long gone, but we still have the memories. I still close my eyes and see it sitting in the back of dad's full scale hangar ready to be flown.

FLASH FORWARD 35 YEARS

There will be more stories to tell as the build progresses but for now lets start with the build! :)
 
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Bipeguy03

150cc
Now bear with me as this build will be a little slow going at first.

A few years ago dad found a set of "King Kong Krier" plans on ebay for sale and picked them up pretty cheap. They promptly got put on the shelf as one of those "that be neat" days. Well those days have come.

After getting the plans out and going over them and the changes that needed to be made I decided I would completely redraw the plans. While I'm not changing the construction method (former over box) I did want to change other things such as making the box a truss instead of just sheet balsa, and making the box wider. And decided that redrawing the plans would keep mistakes due to cluttered plans while building less of a chance.

So, here's the plan. Even though grampa built the model with the intention of being as a good scale representation of the full size counter part, he always planned on it being a sport model that would be flown and flown a lot. With that in mind, my build is going to be a SCALE MODEL OF A SCALE MODEL. Sounds weird huh? I want my model to look just like Grampa's does in the previous pictures just with modern equipment.

So a few days ago I broke out the plans, all of the pictures I could find of grampa's Krier; my pencils, straight edges, compasses, and rolled out the paper and went to work.

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I also have a set of .60 sized Gordon Whitehead Krier plans to help me get the shape down. Grampa has his memory and an old issue of Air Progress with an article on Hal and his Acro-Master to help him.

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Bipeguy03

150cc
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I started by tracing the outline of the original plans as well as the placement of the internal box and bulkhead placements. To shorten the nose and make it look more like a Krier and less like a Bucker, I had to remove the first 2 bulkheads, F1 and F2, shown on the original plans. I then removed the Bucker hump in the turtled deck and added the downward angle to the forward deck.

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With my outline done I went about drawing the structure. I changed the internal box from sheet balsa construction to a 5/16 x 5/16 truss using the original placements of the bulkheads as the positions of my upright trussing. I will also add a 1/8" Lite Ply doubler to the inside of the box that stretches from the firewall to the wing saddle which ties the firewall, lower wing mounts and cabane mounts together and cut triangulated lightening holes in the lite ply to keep the weight down.

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Dad was able to find a copy of the 1964 Air Progress mag that Grampa had when modifying his Krier. This was what the full scale looked like when Hal himself owned it. He later sold the it to Charlie Hillard who changed the shape of the tail to accommodate a larger engine.
 

Bipeguy03

150cc
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With most of the structure in the side view drawn I turned my attention to the top/bottom view. My intention is to build the airplane upside down over the plan and be able to add the side formers and most of the bottom stringers before I ever have to take it up from the plans.

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Using the original former drawings I was able to determine how much wider I was able to get the internal box at certain places. Most importantly I was able to open it up from 4 inches wide to 6 inches wide at the radio compartment, and forward to the fire wall giving me more room for fuel tank and possibly a smoke system?

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Traced out all of the formers from the original plans, then using the side and top/bottom drawing extrapolated the necessary changes needed for getting the outline and new internal box opengings the correct size. I plan on most of the formers being made of 2 or three pieces.

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The changes starting to take shape, right now it all looks like a bunch of lines and dots but to me I see formers! lol

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First 2 formers with their new final shape, other that I forgot to add the holes for the 1/4 x 1/4 bottom stringers. DUH!!
 

Bipeguy03

150cc
So a little more about Grampa's Krier.

Shortly before he got sick he got to take his Krier to many fly-ins around the Ohio/Indiana aera. At one of the fly-ins a writer for Radio Control Magazine was there and talked to him and snapped a few pictures of the Krier. It was later in the Big is Beautiful section of the November 1987 issue of RCM.

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Dad tells me grampa kind of scoffed that the writer called him a master builder and said he wasn't good enough to be called that... Well Grampa, I still have your Skybolt that is now 35 years old and still looks better than most brand new airplanes, so you were a master builder.

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We also still have some of his RC log books, This is the one that has the Krier's log. Now he didn't write down every little 5 minute flight but covered most of the high points. This little booklet is over 45 years old! One of the coolest things about this is I keep a log of my Giant Scale birds as well, same thing just the high points, but our hand writing looks so close you would swear the same person wrote all of it!
 
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