This is a semi-scale model kit of a Fournier RF4, a motor-powered single person glider. The kit is about 10 years old, and is intended for a brushed 400 motor (I'm using brushless) and 3 channel operation. The wingspan is about 1500 mm (59"). The wood parts are CNC-cut (cut by machine instead of die-cut or laser-cut), and some hardware is included.
(I can't believe my wife is letting me get away with building model airplanes all day while she's so busy cleaning up the whole house, and cooking fantastic meals!)
The kit does not have landing gear, but the full size has a single retractable wheel.
I have a small retract that I will use. I already programmed my radio so the retract toggle switch will function on the fourth channel (I'm using a 4-channel receiver); the model does not have ailerons, and that's how I'll build it. I fly other 3-channel gliders (no ailerons) with ease.
The wing is supposed to be held on with elastics, but I will have to cut out part of the center wing to suit the retracted wheel. I will re-enforce the center of the wing, and permanently attach/glue it to the fuselage fuselage for more strength.
Construction started. Interior fuselage framing.
The wheel retracts forward. It's going to be a tight fit, but I still like the idea. Then again, one non-retracting wheel hanging down wouldn't look so bad either. We'll see.
Quote from: Michael on March 31, 2020, 06:10:42 PM
The wheel retracts forward. It's going to be a tight fit, but I still like the idea. Then again, one non-retracting wheel hanging down wouldn't look so bad either. We'll see.
It's so much easier when you can lay it all out on paper... ::)
Great project/even greater wife. :) :) :)
I remember seeing an aerobatic pair of RF4s at an airshow in the UK, doing a display to "Shine On You Crazy Diamond" in about 1985/86. :)
This is going to be a model I can't wait to see Michael. Thanks for posting the build info.
Looks like a fun build Michael
I've noticed in your build pics you use a sheet of insulation and what appears to be a hobby mat to assemble on
I'd rather not go into a store at this time, so looking to order a base to go on my table.
Could cork be a substitute?
Thanks
I use the cutting board for cutting; it also has measurements and angles to help.
I do assembling and gluing on wax-paper-covered plans/styrofoam.
After careful examination of the formers and the construction, I am giving up on the retractable wheel idea.
As it is, there is no battery hatch on the plane, and the battery is supposed to be installed when the wing is taken off. I don't like that. I will figure out how to make a hatch.
Also, the wing is to be held on with elastics. I'll change that too.
Quote from: msatin on March 31, 2020, 11:37:02 PM
Looks like a fun build Michael
I've noticed in your build pics you use a sheet of insulation and what appears to be a hobby mat to assemble on
I'd rather not go into a store at this time, so looking to order a base to go on my table.
Could cork be a substitute?
Thanks
Hi Mark. What I like to use is a sheet of drywall. It holds pins well, is dead flat and is cheap. When the first side gets covered in glue and paint and whatever else, I simply turn it over and have a whole new side.
Mark,
I use drywall as well. I draw a straight line on it with a black Sharpie and a metal ruler. I use the line to join fuselage halves so they stay true and for spars when building a wing.
The most important part is not the final surface but the surface on which the drywall sits. It needs to be absolutely flat*. I use the cheapest flat surface available- a new masonite door from the Re-Store for $20.00. It is surprisingly tough to find a true used door. Doors that have been used eventually conform to the crookedness of their frames.
For cutting wood, I use the same green cutting board as Michael.
FWIIW,
Frank
* it does not have to be level.... just flat and true.
Thanks for the feedback gents
I will have to see what I can source and actually get home in the short term.
Home depot is still offering curbside pick-up.
Formers into fuselage sides.
Adapting the model for a brushless motor, and making an access hatch has taken a lot of careful planning and work. So far, so good.
Sheeting on rear fuselage top.
The fuselage is supposed to be finished before proceeding, but I like to make sure the control system is in place first, so I started the tail 'feathers' before sheeting the fuselage bottom. This way, I can set up all the linkages to the tail and secure the pushrod sleeves in place, while I have access to the fuselage interior.
I may also complete the wing before completely finishing the fuselage.
Slow down, Michael :)
It's keeping me sane and preoccupied.
Ben,
I would like Maidenfest to be "clearance to travel" plus 1 week. Michael is rushing to beat it. ;)
This sure is a weird new normal.
Frank
Maybe not to beat it, but certainly going for the "Most Planes Built" category.
We need to create categories for Maidenfest honours:
Most built
Biggest build
Smallest build
Fastest Build (Honour System)
Slowest Build
Best Repair (before and after pics submitted)
I've started on the wing. The weirdest thing is, although the parts fit is nearly perfect and the assembly is elegant, the instructions call for the wing halves to be simply butt-glued to each other, without any kind of brace.
I will definitely modify this with 2 thin plywood dihedral braces, one in front and one in back of the upper and lower hardwood spars.
looking forward to seeing it fly Michael. Looks great.
Wing: basic construction done. Webbing installed and wing tips carved/sanded.
Customized center-section: Plywood box built round the hardwood spars, and a plywood dihedral brace fashioned.
Michael,
Great build.
I give up. Why the silver goblet?? To hold pins, chocolate, wine, stronger spirits?? ???
We have been totally outclassed. All I can manage is an empty Tim's cup. ;D
Frank
It's a dessert cup.
My wife is cleaning and reorganizing the whole house, and is occasionally giving me broken things to fix.
The stem/pedestal was broken off the cup.
How did you determine the dihedral angle Michael? Was that in the plans?
Yes, the dihedral angle was on the plans; specifically marked 6 degrees each wing.
Wings glued together, 2 dowels glued into the front edge of the wing, and matching holes in a piece of plywood in the fuselage.
A plywood plate is secured in the fuselage under (on top?) of the rear wing, holes drilled and then tapped to match nylon screws. Thin plywood glued on the wing, and then holes drilled for the screws.
(Photos are not in order, but are named/numbered in order.)
fuselage under wing.
Pushrods, linkages, horns, etc., installed, and braces in the fuselage placed to keep the pushrod sleeves in place.
Fairings at rear fuselage at fin-stabilizer.
A little 'imagineering', without cowl cheeks and canopy, and then some more sanding before covering.
The pic with the assembled plane really puts it into persepctive
Very nice!
That's beautiful
Hey Michael,
I think I have the same kit. How long have you had yours?
Glenn
I bought it a month ago, from A+Js.
Michael,
Looking great.
I made a similar size but lighter 3 channel Fournier (5' span) from British plans for an .049 before I joined TEMAC. It would not fly. In fact it did a flip into the ground (tall grass).
Then I changed it to a speed 400 geared and it flew fine at TEMAC.
Lessons learned:
1) Reduce elevator throws. This is a very short-coupled airplane. Travel- normal x .5!
2) Make it nose heavy because it is short-coupled. A rearward CG starts major galloping.
3) Have significant rudder throw because of the long wings and short fuse (leverage).
4) Add wash-out... both wings*!- the first flight had slight wash-in on the left wing (it flipped left)
5) Make gentle turns until you get used to the plane. I gave it a sharp left turn into the wing with wash-in. The good wing was advancing (outside circle therefore faster airflow over the wing) and the left (bad) wing was receding with slower airflow (reduced lift) over the flat-bottomed wing. The perfect storm for a flip.
It's a fun airplane.
For what it is worth.
Frank
* wash-out is when the trailing edge is higher than the leading edge of the wing. (twist)
All great ideas, which I will incorporate.
Thanks, Frank!
I cut out the molded cowl cheeks, but was not happy with how they fit onto the fuselage, so I carved/shaped new ones out of balsa.
They fit well and look good on the fuselage, along with minor changes to the cowl.
I put magnets on the front and rear faces of the battery hatch. and corresponding areas on the fuselage. It works quite well.
Covering started.
Phase 1 covering finished.
Phase 2 covering started.
Cowl and cowl-cheeks.
More covering.
Simply wonderful
Stunning Michael
My jaw dropped as well. It is like the covering was painted on. The newbies, I am sure, would appreciate a workshop or two on covering balsa using various coverings. You are an artist Michael!
Thanks guys, and good idea, George.
Maybe a live Zoom TEMAC meeting on covering, in a week or two.
What do you guys think?
Covering continues.
A work of art. How do the cowl cheeks (excellent name) stay on? I can't quite tell by the pics.
Cowl cheeks inner slots fit over small balsa pieces; will be glued later on.
Stabilizer.
Love the colours! Looking forward to seeing that beauty fly.
Guy
I dunno, that left side of the stabilizer has some of the trim that doesn't quite line up! ;D
Fin/rudder, with photo inspiration.
Tail and rear fuselage.
Good idea about the online meeting and covering tutorial Michael. I am in. Let me know when.
A covering tutorial would be terrific Michael, and couldn't come at a better time. I hope to start my 1st covering attempt on a balsa kit in the next couple of weeks or so.
I need to get a heat gun, none of the local shops seem to have them in stock.
I assume I can use a regular one from hardware store as long as the wattage is the same?
This is the one I bought. Haven't tried it on covering yet. Used it for heat-shrink tubing. I like the dual temp setting.
https://www.homedepot.ca/product/black-decker-dual-temperature-heat-gun/1000140753
Mark,
re: the heat gun.
A heat gun is a "nice to have", not a "need to have". A regular sealing iron can be used to shrink any and all covering. Attach the covering at a medium setting and then shrink it at a higher setting. I did not get buy first heat gun until I had built about 5 .40 size airplanes.
Most heat guns at a hardware store are way too hot because most of them have a paint stripping setting... the equivalent of a blow torch. A regular hair dryer doesn't get hot enough.
Frank
I cut out some letters and applied them. I used similar red sticky-back trim.
... and mistakes are made, and then corrected.
I applied heat to the sticky-back letters on one side, and melted the whole thing. I patched it together and fixed it up. In most situations, people won't notice, but upon a closer look, the repair work is visible.
Quote from: Michael on April 12, 2020, 12:55:27 PM
... and mistakes are made, and then corrected.
I applied heat to the sticky-back letters on one side, and melted the whole thing. I patched it together and fixed it up. In most situations, people won't notice, but upon a closer look, the repair work is visible.
Michael, if you had used Frank's camera, no one would have noticed. Still looks great mind you!
Cowl, cheeks, and 'tail-feathers' glued on. Radio set up.
Total weight including battery is 21.6 oz / 614 grams.
I still need to decorate and attach the canopy, and probably a pilot.
Michael,
Looks great. I love the instrument panel.
Bruce, about your above post:
re:"Michael, if you had used Frank's camera, no one would have noticed."
You are so kind to blame it on the camera. Mr. Hoffer always blamed the photographer. ;D
Frank
Thanks, Frank.
The instrument panel is from an image I found on the internet, of an actual RF4 instrument panel.
I copied the image, distorted, transformed, saturated the colours, brightened it, and sized it, in Photoshop.
It was printed out, and then glued down with gluestick, and covered with clear Monokote.
Canopy trimmed, sanded and decorated.
I won't install it until I get (or make) a pilot figure.
I may glue it or screw it on; I'm not sure yet.
Beautifully done, Michael.
Another excellent and fast build from the Pres!
Thanks Robert.
Done for now; waiting for some lead weight and a pilot figure.
While I'm waiting for a delivery of balsa wood for my next project, I went back to finish off this model.
I carved a pilot out of styrofoam, and painted it, a bit of an improvement over my previous attempt, I added a little bit of weight to make it a bit nose-heavy, I attached the canopy, and I added some wash-out (rear outer wing tips twisted up) to help prevent stalls.
Fully ready to fly.
Nice pilot. I'm tempted to try carving one myself. I don't feel artistic, but I do need a pilot of the correct size for one of the planes I'm working on, and carving might be a fun experiment. Plus I'll eventually need aircrew for some of my other projects that are not of standard scale of available pilot figures. So I'll need to develop the skill at some point.
Robert
While I'm waiting (still) for a Canada Post delivery of balsa wood, I decided to add some scale-ish landing gear to this model.
The tail wheel bracket is made of of plywood, aluminum tube and wire and covered in white film. The images are basically self-explanatory.
The main gear (one wheel) is simply a larger-scale tail wheel unit. It looks right to me.
Wing mounted landing gear is carefully measured and bent wire, braced onto small holes in the hardwood wing spars.
The finished model. Now it will take off instead of being hand-launched.