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FTFC20 Rutan Model 68 AMSoil Racer by Boberticus

Boberticus

Active member
#1
Bert Rutan designed some marvelous airplanes, but none really have ever captured my imagination more than this legend of an aircraft. Even today, this design has significant aerodynamic advantages over traditional fixed gear, and weight savings over retracts. Its truly a remarkable design that deserves to be more than just a memory for the few.

The AMSoil Racer, Model 68.

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Burt Rutan had designe the QAC Quickie some years before, and it was a popular kit, but a 25hp motor and outdated NACA airfoils didn't lend to the slippery air frame the performance it deserved, and pilots lamented that this wonderful design would forever be a fuel sipping featherweight.
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Enter Dan Morrison, Salesman for AMS racing, who raced the Reno Air Races in his spare time. he wanted to win, and he wanted to win in something now one else had won in before. and so the AMSoil racer was born.
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(heres a pic of Rutan overlooking Dan in the Model 68, sometime around 1980)

Gone was the tiny efficient motor, the outdated airfoil shapes, and the weight of frivolous fuel tanks. In came a 200HP lycoming engine, a set of airfoils designed for 60% laminar flow at 250mph+, and a fully pivoting horizontal T-stabilizer to give extra pitch authority while ripping at 90 degrees around a pylon. Furthermore, Dan changed out his AMS brand racing oil every race, and ran the engine up to 15% past redline every chance he could. The Model 68 was built to do two things, go fast and turn on a dime, and it excelled at both.

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Its a pity that this legend of a aircraft only flew a few years before being crashed, a one off, never to be built or flown again...



https://outerzone.co.uk/plan_details.asp?ID=11273

the plans from outerzone link are in italian, it was designed in 1996 so in hopes that the original balsa designer, Giuseppe Ghisleri ever sees this,

Lavoro meraviglioso, che bellissimo aereo, grazie. This was a spectacularly documented airplane, there is no way I could have done this from scratch.

I'm certainly not finished yet, but am starting the build thread, mostly to have a way to get it at work to print off the templatesd (hand cutting all of this, id better be right) but im also posting to start asking questions.

Im doing this in inkScape, following NerNics build videos, and am i thnk mostly done except for Labeling everything, the power pod and its placement in the fuselage, and the posterboard bits ill have to cut out and then scan, and get the 3d printed parts modeled and uploaded to thingiverse.

Designing this was pretty hard, but really fun, and the next one will be much easier. i have a 64mm EDF just begging to be built around

This is my first plane, so go extra hard on any mistakes you guys notice to make sure I get things right;)
 

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speedbirdted

Well-known member
#4
Oh that's slick, looking forward to seeing it done. There used to be plans for a 1/3 scale Quickie floating around which had about a 60 inch span (damn the quickie is a tiny plane!) and took I think a .60 4 stroker, but I've never seen one built. I'll take a look through the plans for this, and if I already have all the electronics... might build one up? Can't see a reason why not to. I'll follow your lead though since I'll probably find some way to screw it up, that being my specialty...

Also, the reason people will reserve extra posts is so they can put the beauty pictures of the finished build there after it's all done ;)
 
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Boberticus

Active member
#5
yeah, i think i made plans from the 1/3 scale version, looking at a wingspan of 50 inches without the wheels on the canard, a 35 inch back/upper wing, and a overall length of 55 inches. gonna have 4 arrows to make the size and stiffness of the frame work out.

8 sheets and i nearly filled them all up, shes gonna be a big graceful bird!!!!! :D
 

Boberticus

Active member
#7
yup, and i have a 400w .45 electric equivalent to slap on in there once I think it'll fly.

honestly, i'm sort of nervous, this will be the biggest plane (by wingspan) ive ever built by at least a foot and a half, and im hoping that the weird blend of classic flighttest foldover,+multiple airfoil formers+carbon arrow spars + intregrated landing gear attachment point is strong enough.

I'm hoping that the foam makes up for the lighter weight motor compared to what it was originally built for, but i want to make a power-pod to fit it, the big radials from the flitetest store, and the big prop-drive motors NercNic swears by, then look into a lighter-weight motor version (maybe have to make a mini for that).
 

Boberticus

Active member
#9
Okee Dokee, got some work done on the fusealage tonight. This thing was so big I had to rearrange my room to fit two tabels in here to get this done.
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got the two fuselage halves cut out and fit/glued together, and all formers but the last one cut out, got the extra blocks of foam stripped of paper, and glued to the rear wing mount. the wing profile on the sides of the fuse will be used to carve out the shape for a good connection between the removable wings and the rest of the airplane.
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i also couldnt help it and mock tape mounted it all together for a quick check. just for science.
nobody build this yet, there are quite a few mistakes in the plans I'll have to tidy up, but they're mistakes like off by the width of a sheet of foam, carry the 2, dot the i kind of stuff...

im keeping a list and ill get them done before i update and label the plans.
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Grifflyer

WWII fanatic
#10
Okee Dokee, got some work done on the fusealage tonight. This thing was so big I had to rearrange my room to fit two tabels in here to get this done.
View attachment 153846
got the two fuselage halves cut out and fit/glued together, and all formers but the last one cut out, got the extra blocks of foam stripped of paper, and glued to the rear wing mount. the wing profile on the sides of the fuse will be used to carve out the shape for a good connection between the removable wings and the rest of the airplane.
View attachment 153850 View attachment 153851 View attachment 153844
i also couldnt help it and mock tape mounted it all together for a quick check. just for science.
nobody build this yet, there are quite a few mistakes in the plans I'll have to tidy up, but they're mistakes like off by the width of a sheet of foam, carry the 2, dot the i kind of stuff...

im keeping a list and ill get them done before i update and label the plans.
View attachment 153845 View attachment 153849 View attachment 153847
Off to a good start!
 
#12
Got the tail finished up, with the swiveling h-stab and a nice integrated spar for stiffness
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I first cut a v groove where the tail shaft goes, then uses the shaft to rub down just past halfway mark all the way down to the paper to form the groove in to a nice perfect fit.
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I Printed off a swivel that connects the carbon fiber rod to the h-stab, and provides a stiffener/spar for the vert-stab. the groove it sits on the paper was removed and the spar is pressed in to both sides to get ti to fit without removing the foam.
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the front and back of the vert-stab has been shaved down and glued up with the control arm and swivel mounted within

20200111_160230.jpg 20200111_161010.jpg nice and aerodynamic....

I then glued it all up, and fit it together, then wasted a solid two hours figuring out the metal control rods
20200111_163143.jpg everthing installed..

the tail seems pretty sturdy, the forces of the tail will be transfered directly into the fuseage without a big risk of tearing out of the foam. Its still pretty light too, even though its still unglued together and lacking a packing tape skin.

now that the tail is complete, I can finish up the last bit of details with the fuselage and then move onto the wings.
 

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