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Dutch RV-12

dennis nl

I'm New Here
Hello
I would like to introduce myself, I am Dennis from the Netherlands. I have been a fanatic model aircraft builder and flyer for over 25 years and competed in international level for many years. A few years ago I was looking for a new challenge which I found by building an RV-12. After obtaining my pilots license I ordered a RV-12 kit which I started building at Christmas 2011, after two and a half year of building I made the first flight on August 31st. I would like to share some of my experience of building and flying the RV12 with you.
Based on my background with model aircraft I decided to modify and add many parts to my RV12.
Below are some of the changes I made.

Fairings
Most of the added parts are fairing in an attempt to reduce the drag and improve the appearance.
Fairings added are:
Horizontal stabilizer tips, to give them a rounded tip.
Between the wing and fuselage. This smoothens the junction making the rubber squeezed between the fuselage and wing invisible.
Between the fuselage and the fin. To smoothen the junction.
From the wheel covers to the fuselage. The standard lag is square which isn't the most aerodynamic efficient shape, therefore I covered the leg with a fairing that connects to the wheel cover and the fuselage, see picture below.
A vanity panel above the instrument panel to hide the canopy tubing.
Weight reduction
Next to that I have reduced the weight of many of the standard composite parts engine cowl, wheel covers, tail cone, by using sandwich composite construction. Whereby I laminated a honeycomb material in between two thin composite layers. The added thickness created by the honeycomb increases the stiffness tremendously whereby less layers of composite are needed, thereby reducing the weight. Resulting in a empty weight of 731lbs.
Elevator trim improvement
Based on articles on this forum and some initial tests on the workbench it seemed that the elevator trim was difficult to control accurately. Making fine adjustments over the complete flight envelope is impossible. I wanted to improve this to make the system more robust. Therefore I requested a friend, with an aerospace degree from University of Technology in Delft, if he could help me. I wanted to keep the system as original as possible such that the standard trim servo with its build in safety mechanisms would remain untouched, as well as the wiring loom through the aircraft.
After some initial prototypes this resulted in a system whereby the whole travel range is divided into 200 equal steps controlled by a new instrument in my cockpit (standard 57mm mounting). On this instrument I see a digital readout of the position of the elevator which can be controlled to increase/decrease with 2 buttons on the instrument or on my control stick. In addition there are two more buttons on the instrument to store preferred positions. To ensure the safety of the device there is another part mounted in the tail next to the servo motor, this part converts the position measured by the servo from a voltage into a coded signal. This makes the systems insensitive to outside disturbances or changes in resistance of the wiring (for example by aging connectors). It is even able to detect when the system is damaged, and will report this back to the display.
Flight experiences
The RV-12 flies very well, and am enjoying it a lot. It uses very little fuel and can fly very fast.
The trim instrument has been impressive especially the digital readout which shows the position indicated between -99 & 99.
And the two memory positions are great. When I take off I push one button shortly, whereby the trim goes to the take off position. And after reaching cruise speed I press the second button to bring the trim to its cruise position. While still allowing me to make fine adjustments, even at high speeds.
Below are some pictures of the RV-12 during building.
Best regard,
Dennis

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Very nice work Dennis. I suspect you will be answering a number of questions regarding your mods. Beautiful airplane. Congratulations.
 
Very impressive workmanship and attention to detail. I'll bet it flies every bit as well as it looks!
 
Probably one of the nicest RV-12 flying, just watch out for the wind mills, you have one that looks quite imposing on a picture!
I envy your trim system, could you provide more details? I learned to fly on a plane that had a simple mechanical handle to control trim and I still miss the easy way to set the trim for different phases of flight as you do with your digital system. The problem with the RV-12's trim is that you are constantly fiddling with it, to the point where I keep my hand on the throttle in flight as it's the best position to operate the trim button.
Congratulations for an impressing workmanship!
 
Dennis,

VERY neat trims around the wing roots, tail and wing tips.

Have you thought about passing the info to Vans? I'd certainly be interested in adding them to mine (SLSA).

Great looking airplane!!
 
A beautiful job....would love to know how you modified your pitch trim (parts list, etc.

I too, will have stick hat switches; but to have pre-selected setting for take-off, cruise...not to shabby🍈⚡
 
Thank you very much for all the compliments.

Here are a few detail pictures of the stabilo tip

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best regards,

Dennis
 
Very nice Dennis.

Is there a possibility to buy your fairings. Could you make some and if yes, how much would they cost? I am particulary interested in the VS/Tailcone and Wings/Fuselage fairings.
Thank you !!
 
How I make the wing fairings:
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We put the wings to the fusselage and make the form whit modelling compound. http://shop1.r-g.de/item/310100I

Than we wax it 5 times whit Priming wax http://shop1.r-g.de/item/165115
After that 1 layer of PVA Film release agent PVA http://shop1.r-g.de/item/165110
Then we put 10 layer of glas tape 225 gr on it whit epoxy Glass fabric tape 225 g/m? (Silane, plain) 100 mm http://shop1.r-g.de/item/200145
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After 24 hours, the epoxy is hard and we finished the fairing

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Now there is a fairing whit the exact shape of the wing and fuselage.
 
Dennis,

Wow, that's some really amazing high-quality work!

I'm curious: when you mentioned that your RV-12 is really fast, what sort of speeds are you seeing?
 
Nice

Looks Nice,Dennis!
My flightbuddy and me are planning to build a 12 ourselves - do you mind we come and have a peek, these days?
Love to use your friends fairings, as well?

Please contact me on Hans.labruyere [at] gmail.com?

Greets & many happy landings!
 
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