Druine Turbulent

Tank Compartment

Ample room in the forward fuselage

compartment for batteries and just

about any sized tank.

R/C Aircraft Insight From Low Altitude

John W. Blossick Tail Slide Haven johnb@tslidehaven.com October 2020

Fuselage Front

Another side view showing fuselage

plywood bent over and glued to spruce

center stringer.

Fuselage Bottom

Servo mounts installed. The underside

of the tank compartment will be covered

with 1/4” sheet and sanded to match

fuselage and cowl contour.

Landing Gear

Okay, I’ll admit it. Bending and

soldering the landing gear was

annoying and time consuming. Despite

the effort, it’s strong and should hold up

well.

Wing Tip

The tips are reminiscent of the internal

soundboard bracing used in a Kasha

braced acoustic guitar and traditional

fan bracing. The tips however, need not

be tuned....just laterally balanced!

Top View

3/16 square stringers and formers

make up the turtle deck

Ailerons and Center Sheeting

Center sheeting and ailerons are added

to complete the wing structure.

Cockpit Area

Large area for pilot, detailed instrument

panel, switches, and charging jack.

The Business End

A Dave Brown engine mount was

used to bolt a Magnum .45 to the

firewall.

Horizontal Stabilizer

The spars on the horizontal stabilizer

will produce an airfoil shape once

covered. The result? Exceptional lifting

qualities for quick takeoffs and slow

landings.

Shear Webs and Leading Edge

The thickest shear webs on the planet

for a .40 sized airplane. 3/16” was used

and despite the thickness, they didn’t

add much weight.

Right Wing Half

Despite looking rather spindly without

sheeting, the wing is super strong. No

leading or trailing edge sheeting is

required in the plan.

I had been looking at the Durine Turbulent for a long time before finally deciding

to build one. A popular modeling subject for

decades, the Turbulent has been modeled

in virtually every size imaginable. A rubber

powered peanut scale airplane wasn’t what

I really wanted to build, nor did I want

something so big I would need a trailer to

haul it around!

I eventually chose the .40 sized RCM plan

designed by Chuck Cunningham. With a

60” wingspan, the size was right, I have an

engine that fits the airplane plan and I liked

the paint scheme too.

Depicting a Swiss motif from the land of a

thousand postcards, the paint scheme

placed the Swiss flag on the top of each

side of wing and the rudder/vertical fin.

Black trim and lettering added some

contrast to the red and white making the whole paint scheme pop. The Swiss

flag also reminded me of Switzerland, of course—then skiing, the Alps, fondue,

Swiss cheese, chocolate, and fine time pieces—all good things. About the

Turbulent...

Still being flown today, the Druine Turbulent was the brainchild of the

Frenchman Roger Druine. First flown in 1951, the Turbulent is a cantilever

wing, home built ultralight aircraft with an empty weight of 349lbs and powered

with a 30hp Volkswagen or similar engine. With a 1600cc VW engine, cruising

speed is around 80mph and has a climb rate of 500fpm. Not too bad, but the

aircraft certainly isn't a speedster, nor is it aerobatic. Aerobatics won't be a

problem for the .40 sized Turbulent though. The model will easily outperform

the scale Turbulent and look good doing it.

For a scale project, it's not difficult to build, and the wood sizes on the plan

make the Turbulent very sturdy. It will easily withstand the occasional double

bounce landing if you're prone to that sort of thing. Onward to the build...

A Word About Covering

I’ve decided to use Sig Koverall and Supercoat dope for covering. I used Koverall on a Smith Miniplane

before and painted it with Pactra Formula-U polyurethane paint. I was pleased with the results. Although a

heat shrink covering will work just fine, a painted surface will look more realistic. Moreover, Koverall is far

easier to apply than heat shrink coverings. It goes around, adheres to, and shrinks around curves wrinkle

free. Dope is also...well...what real airplanes are painted with. I haven’t painted an airplane in awhile, so it’s

time to gear up.

Will dope stink up the joint when you use it? Heck yes it does! Especially when it’s sprayed. It can also cause “permanent brain damage and nervous system damage”..and...”deliberately inhaling the contents may be...harmful or fatal.” Oh, yeah! Now we’re building airplanes!! Of course, when spraying dope one has to take the necessary precautions and use a respirator for sure. Recreational sniffing of noxious chemicals is strictly forbidden. Anyhoo, the effort put into this type of finish is entirely worth it. In actuality, it’s not that difficult. No magic or voodoo, just simple techniques modelers have used for decades.

Find The Best R/C Engine Deals

Completed Druine Turbulent

Airframe covered and filled with three coats of Sig Nitrate Dope.

Actually, it’s 99.9% completed. The RX battery, battery switch, and receiver need to be installed along with the final balance. Finishing with sprayed butyrate dope or paint is considerably more work than an iron on film. But—for authenticity and reproducing the fabric covering used on full sized aircraft, fabric covering and paint is the best way to go.. The Swiss crosses were cut from white Ultracote. The black and red letters were cut from craft store vinyl and 3/16 Ultracote striping finishes the trim. Decals were made with decal paper and the ink jet printer. The paint scheme should be easy to see in the air and I find it rather pleasing to look at. All that remains is to finish up a few items, buy some Swiss chocolate, head to the flying field and put the Turbulent up!