AR-6 Construction Thread
 

The UPS brought a nice surprise today.

Lee was kind enough to send an AR-6 fiberglass fuselage. Kevin Matney provided the foam cores.

Send a PM (private message) to Lee if you are interested in getting a fuselage. Send a PM to Kevin if you want cores.

I'll probably wait until Lee gets back from the Nats before starting on the model.

Please note that this is a builders project as there are no plans nor instructions.

Thanks to Lee and Kevin for making this project possible.

RE: AR-6 Construction Thread
 

Instruction will come, just not high on the priority list at the moment.

I won't be doing any more until after the nats.. They aren't perfect yet but this was only the 5th one I've done.

After the Nats I will finish the wing and tail molds and be offering a full composite kit.

Please PM me with any questions regarding the "builder" version.

Thanks Scott, can't wait to see how it goes.

RE: AR-6 Construction Thread
 

So..... when do I get mine??? :D

I sent the CNC files for the wing tooling to Kevin and Lee tells me that Kevin will bring them to the NATS for Lee to take back with him. Hopefully, I've designed this right and we will have another Q-40 tearing up the pylons in short order. Lee and I are discussing having me make CNC cut files for the fuselage, but it might not be necessary. I've also already made the CNC files for the stab tooling. Maybe someday I'll have the "thumbs" to be able to fly one;)

RE: AR-6 Construction Thread
 

Don't worry Gary, yours is coming.. After the nats ;)

As far as the thumbs go, they fly great when set up properly.. It's the one shot at landing that gets most into trouble when they start flying them..

RE: AR-6 Construction Thread
 

Go man Go!!!

AR6s are cool and all but I want to see the Miss Furious happen. I think that would be a cool looking airplane.

DE<br type="_moz" />

RE: AR-6 Construction Thread
 

Dave: I am not familiar with "Miss Furious", but if you'll send me a link, I'll take a look at it. If it's a Sea Fury derivative, it can't be too different from "September Fury", for which I have mostly finished the design work.

I searched for "Miss Furious" but couldn't come up with anything.

RE: AR-6 Construction Thread
 

Gary, the september fury is the one I was talking about. Lee sent me some drawings of it a couple of years ago and then I seen your drawings. I think it would work well and was thinking about doing one before I started this F5D thing.... maybe after I am done with that. To many AR6s around.

DE

RE: AR-6 Construction Thread
 

I remember when I started the AR-6 thinking there wasn't one.. Then one day I open up the NMPRA site and there yours was.. I just about didn't even do it.. Obviously, I did it anyway.. Looking back, my racing life would have been much less frustrating had I quit back then :D

RE: AR-6 Construction Thread
 

Awww Lee, you will get it and there is alot of satisfaction in knowing you didnt just go buy it. I think it is like the old days of modeling, guys working in there basements on there own design with thoughts of how well it is going to do at the next big competition....Its worth it!

DE<br type="_moz" />

RE: AR-6 Construction Thread
 

Ya, but Dave's AR-6 and ours are different enough that they won't be quite the same, either on the ground or in the air. It's always better to have more airplanes than fewer airplanes. I'm sitting in a hotel all day today and will work on the September Fury 2D drawings for approval submission.

Hopefully, after this years Reno race, there will be a new F1 to model. "Fraid Knot" should make it this year and has a unique wing planform that should make it stand out from the crowd.

RE: AR-6 Construction Thread
 

OK Scott, forgive me for this off topic, but I can't resist!!

Rope walks into a bar

A length of Rope went into a bar, sat on a stool, and ordered a beer. The Bartender said, "We don't serve Ropes here." Dismayed and disappointed, the Rope went out and then got an idea. He stopped a man and asked, "Will you please tie a knot in me and separate my strands at both ends?". The man obliged, and with this done, the Rope went back into the bar and again ordered a beer. The Bartender looked him over and said, "Say, aren't you the same rope who was in here before?!" "No," was the reply, "I'm a frayed knot."
:D

RE: AR-6 Construction Thread
 

I wonder if the designer would let us do a Q40 of it.. ;)

RE: AR-6 Construction Thread
 

Ya know, I'll bet if I asked him real nice that he would say yes... I'll go ask... Yep, I thought so. See what happens when I get locked up in a hotel room... I start talking to myself...

RE: AR-6 Construction Thread
 

I've been drooling over the AR-6 ever since I got the fuselage. It's time to look at some of the details around the wing.

The AR-6 has a very low tail and therefore needs a long landing gear to provide room for flight rotation on takeoff. Lee indicated he used 4" long legs on his model.

I looked around my shop and came across Kevin Matney's Q500 gear. His longer gear has very close to 4" legs.

The following pictures show the conversion into a Q40 gear:




The sketch shows a couple potential locations for gear. You want the gear far enough forward that the model doesn't nose over on takeoff, but not so far forward that the model bounces on landing or is difficult to use the muffler break.

RE: AR-6 Construction Thread
 

Here is one method to make the wing skins:

Begin by weighing each sheet of balsa.
I then place the heaviest on the top and lightest on bottom.

RE: AR-6 Construction Thread
 

Use the outline of the shucks to define the size.

Trace the pattern about 1/2" wider than the wing cord.

Make the length about 1/4" longer.

RE: AR-6 Construction Thread
 

Select several of the heavier balsa sheets and use them for the top sheeting.

I try to use the heaviest wood on the left hand side of the wing. This helps counterbalance the engine weight.

Place a sheet of wood at the front and back of the skin template. A third piece of wood is fitted to go between the front and back pieces.

The sheets are taped together at the seams with masking tape.

RE: AR-6 Construction Thread
 

Make the other top skin with heavier wood.

Make the bottom skins with some of the lighter wood.

Lay out the skins and label them on an area that will be glued to the foam.



I made a second set of skins for another wing. Note that a different colored marker was used on the second set.

RE: AR-6 Construction Thread
 

Two 1/8" thick hard balsa spars form the support for the future landing gear blocks.

I didn't have any 1/8" thick balsa so two thicknesses of 1/16" thick were glued together.

The spars are 16" long and are trimmed to fit flush between the top and bottom wing sheeting.

RE: AR-6 Construction Thread
 

The main spar is actually a 21 thousandths thick x 1/2" x 36" piece of carbon fiber laminant.

A slot is cut on the top surface of the wing cores.

RE: AR-6 Construction Thread
 

A piece of 7 thousandths x 7/8" x 50" carbon fiber laminant provides tensile strength on the bottom of the wing.

Plan the location of the fiber so that the landing gear blocks don't interfere.

The wing skins are taped together so that trailing edge makes a hinge. It's sorta like a book or taco.

RE: AR-6 Construction Thread
 

A layer of 1.6 ounce fiberglass cloth provides strength for the wing and provides the basis for a thin trailing edge.

RE: AR-6 Construction Thread
 

Mix about 3/4 ounce of finishing epoxy and glue in the spars and wing halves together.

I pinned parts in place while drying.

RE: AR-6 Construction Thread
 

The vacuum bag is made from 4 mil thick plastic sheet.

The plastic sheet size shown (3 foot width) in the pictures works well for making bags as you just cut a piece a little wider than the span.

RE: AR-6 Construction Thread
 

Mix approximately 1 ounce of finishing epoxy and then add about 0.1 ounce of 91% alcohol.

The alcohol thins the mix and allows it to flow on easier.

Apply the mix to one side and use a plastic squeegee to spread out the epoxy.

The remaining side is done the same way.

RE: AR-6 Construction Thread
 

The core is placed on top of the wing sheeting and the top sheeting is later folded over top of the core.

I pinned the sheeting to the cores in the appropriate location.

The sheeted cores are then fitted between the shucks. Pin parts together insuring that parts fit properly in the shucks. Tape the parts together so that pieces don't move while drying.

Place the wing core on the plastic tarp. Tape a piece of twine down the side of the cores. Place a long piece of paper towel on top of the cores. Tape the vacuum line near the twine.

Apply a bead of latex caulking around the cores. Fold the plastic tarp over and seal the edges by stepping on the tarp to smash the caulking together. Apply a couple quarts of paint near the center to insure parts are straight.

Turn on the vacuum pump and pull about 5 inches of Hg. My pump turns on around 3 inches and shuts off around 6 inches.

The finishing epoxy typically dries overnight, but if it is cool it will take longer to dry.

RE: AR-6 Construction Thread
 

Trim off the outside of the bag and remove the wing.

RE: AR-6 Construction Thread
 

Make sure the wing fits correctly with the shucks and then trim the leading and trailing edges with a razor saw.

RE: AR-6 Construction Thread
 

Trim the leading edge flush to the foam using the razor saw and sanding block.

True up the trailing edge as required. Each tip should be the same width.

RE: AR-6 Construction Thread
 

After trimming the leading and trailing edge the wing is starting to take form.

I couldn't resist a picture with the fuselage on top of the wing.

RE: AR-6 Construction Thread
 

I vacuum bagged a second wing tonight.

This wing is 8.5% thick at the tips. The other one is 11% thick at the tips.

RE: AR-6 Construction Thread
 

I will be curious to see if you can tell a difference between the two wings, either in speed or in handling. According to the Xfoil run, the 8.5% tip wing will be more prone to tip stall and not all that much lower drag. But that's just a 2D simulation and I don't always believe simulations.

The 700,000 Rn is roughly 160 mph and the 220,000 Rn is roughly 50 mph (landing)

RE: AR-6 Construction Thread
 

I glued the leading edges on with Gorilla Glue. You dampen the surface with water prior to gluing. Just use a small bead as this type of glue expands and fills up any gaps.

RE: AR-6 Construction Thread
 

Here's a side view that shows the 11% tip and 8.5% tip.

RE: AR-6 Construction Thread
 

The leading edge was shaped with a pocket knife and sanding block.

I just try to make both sides with roughly the same shape. Try to achieve a more rounded leading edge instead of sharp edge.

The last couple pictures show the 11% wing tip and 8.5% wing tip.

RE: AR-6 Construction Thread
 

The following pictures shows the installation of landing gear blocks:

The blocks are glued in with 30-minute epoxy and micro-balloons.

The gear is temporarily held in place with tape to insure that the blocks are in straight.

RE: AR-6 Construction Thread
 

Here are some pictures showing the installation of the gear.

Each leg of the gear will be held on with four 10x24x1/2" nylon bolts.

RE: AR-6 Construction Thread
 

Here are a few more pictures of gear installation:

RE: AR-6 Construction Thread
 

The wing leading edge and fuselage must be sanded to fit. Take your time, it doesn't take much fitting:

RE: AR-6 Construction Thread
 

Spot the aileron and torque rod locations.