AndyKunz

Last weekend my club (www.elifield.com) was supposed to have a Builders Contest, and I was the one who suggested it so I got to be the event director.

My plan was to bring my Kaos and enter it into the Bashed ARF category (recovered and converted to electric).

As luck would have it, we had really strong winds and unseasonably cold temperatures, so the event was postponed two weeks. Monday night, I had the itch to build, but I wanted something quick that I could take to the rescheduled Builders Contest.

Here is what I have right now. You get to figure it out.

A few hints:

1) It was originally designed by a well-known AMA figure.

2) Different versions of it were published by at least two magazines (FM and MA).

3) One of the published versions was electric when electric was still in its infancy.

4) If you know me, I've been itching for a bigger one for almost 2 years (I had a smaller kitted version).

5) It was kitted in several versions, ARF in several versions, and now discontinued (though the kits are popular on ebay).

Hopefully I didn't make it too easy.

Andy

Rendegade

Duellist!

ha!

R_G

My Feedback: (1)

Is it a flying wing of some sort? A Scimitar maybe?

doxilia

My Feedback: (3)

Mmm...

well, points 1 to 5 correspond to a Hots but that fuse is not a Hots. Curious looking fuse actually. Can't figure out which way is up.

David.

Edit: Oh yea, Ralph, I think you're on to something. I get it now. Basically a stub fuse to join the delta flaperon wing to the vertical. What was the name of the popular design - something like a Sig Wonder but not quite.

jfuller

My Feedback: (8)

Well, you didn't make it too easy for me. I have no idea.

Jamesf

AndyKunz

Not a Duellist, mot a Scimitar, not a Hots, not a Wonder.

Somebody isn't too far off, though.

Another hint: The wing has dual taper and a symmetrical airfoil.

Andy

Free Bird

How about a Shrike?

FB

R_G

My Feedback: (1)

I still think it's a wing of some sort, just don't which one! I'm not up on flying wings.

doxilia

My Feedback: (3)

Shrike!

that's the one I was thinking of - thanks Rick. Is that it Andy?

If not, might it be a scale jet model?

Don't really know if it might correspond to the criteria but a dual taper wing could be a modern jet fighter - Raptor (F22), Lightning (F35)?

David.

AndyKunz

Free Bird got it first. It's a Shrike.

I had a Speed 400/.049 kit from just before Bubba sold out to Hobbico that I put together two years ago when I moved to IL. I had it powered by the equivalent of a .10-.15. It was a rocket and lots of fun, but due to problems with my eyes I needed a larger one, so I gave the old one to a friend.

I started by putting the outline of the Speed 400 Shrike (published in Flying Models) into CAD, then scaling it to 35" span and putting a structure within it. This new one has E-Flite electric retracts and a Power 25 Heli motor. Just under 300 sq in. I expect to have a bit of fun with it! I may drop down to a Power 15 if the Power 25 system is too heavy for safe landings.

It's not Classic Pattern, but it's a classic and VERY aerobatic (I'll probably add rudders to it).

Andy

doxilia

My Feedback: (3)

Good job Rick. I guess we were all on the right track.

So Andy,

what are the specs of the speed 400 version - is that the 35" span version? What's the span of the 40 size? What will the span of the 25 be - around 420-450 squares?

I seem to recall the Shrike having a CF tube spar around which the wing was built directly on to the fuse. I see there are holes in the fuse sides - will you be passing a CF tube through it a single piece model? Good old Dave Brown arrow shafts perhaps?

Rudders will be cool - they could be actuated by a single servo in a double rod aileron configuration with horns on the inside of the rudder. Likewise for the ailerons - a single servo in the fuse with torque rods. I guess with retracts though you could use dual ailerons servos nicely tucked in on their sides.

Progress?

David.

AndyKunz

The Speed 400/.049 version was about 24" span. The OS .10 was a popular engine on it. The .15 size was 35" span, which is what I'm sticking a 25 on. Check ebay or google to find the other specs as I don't have them handy right now. I have them on my Linux box, but the keyboard died yesterday (finding a PS2 keyboard is turning out to be a little more work than I expected).

The small one had wooden spars top and bottom, and a wooden TE that went through. I may have sent you plans of my own earlier, and that had DB pushrods for spars. That's what I have on this one.

Dual rudder servos, nice and tiny ones. The ailerons go into the same bay as the retracts.

BTW, I'm going to do doors on the gear to make it cleaner.

I got the wing framed up last night, and got the LE sheeted today. I made the stab (if you can call it that) out of 3/8" balsa square. Instead of triangle gussets I put 1/8" dowels to pin the corners together. The "LE" goes against the TE of the wing and through the fuse. That's the square hole in the photo above. For this I just pinned the corners together but didn't glue. I'll take care of that after joining it all together.

More pix later.

Andy

Free Bird

Free Bird got it first. It's a Shrike.

Cool! That's what I was thinking, and the last set of clues did it for me. The fuse pic helped also! Neat build Andy - keep going at it!

FB

AndyKunz

Time for a few more pix. I haven't been taking them as I go, so what you see is what it looked like this morning when I left the house.

The wings are mostly sheeted. I only have to install the wheel wells (1/16" balsa wrapped around a 2" rattle can for a mold), then cover the center section around the wheels and aileron servo panel, and add cap strips to the top side of the outer three ribs. And make the 1/2" thick tips.

The DB pushrod spars are not installed at this time - they are used as a jig to build, but removed so that I can work easily. They get glued in when I attach wings to fuselage. The big paper tube is .5" ID model rocket body tube used as a conduit for the servo and retract leads.

The fuselage has barn door access. The front hole will be covered by a door when the gear is up. The rear one is the battery hatch and it will be held in with magnets. You can also see the 3/8" sq stab framing. The elevator servo will be installed behind the rear hatch, accessed through the air exit hole (yet to be opened up).

My plan is to finish it the same as my Kaos - white and orange with black and silver trim. Spektrum colors, of course.

Andy

AndyKunz

Last night I framed the fins (no rudders on this one) and attached the wheel wells. Tonight I'm making gear doors, sheeting wing bottom, and adding cap strips on the top side.

It won't be flyable at the Builders Contest Saturday but it will be there. The pressure is still on as I need to get in a few flights before heading off the PA for the LVRCS Ellis Grumer Memorial Electric Fly June 5.

Andy

AndyKunz

It won't be long until I start covering now. This is how I'm taking it to the field tomorrow.

Andy

AndyKunz

I've been working on the plane and not taking as many photos as I should have, but if you're interested there is a thread on RCG in the Builders Workshop forum with a few more pix.

Covering is just about complete. I wanted to show a little trick I use, which is especially important on the Shrike.

We all know you can't glue to covering and expect your model to stay together, and we always do most of our covering before assembling components. So how do you make nice edges and remove the covering where it normally gets so that you can make a strong glue joint?

On the Shrike, this would be the wing roots to the fuselage and the vertical fins to the sides of the stab.

Here's my trick. I make a template the size of what I want to glue using masking tape. It is about 1/16" to 1/8" smaller than the surface (larger surface area is better). In these photos you can see (if you look closely, it's hard to see) where I put masking tape on the side of the stab before covering. I then covered the stab normally, and then cut the film away using the masking tape as a guide for the tip of the knife blade.

In the second photo, I have removed the masking tape and covering that went over it. You can see a nice glue surface left behind. You can also see the 1/8" dowels that peg the stab together.

My goal is to have the Shrike ready for a Memorial Day maiden flight. I would much rather be at Rusty's contest today but I was at an event last week and another next week. I think me being gone three weekends in a row is a bit too much to ask from my wife.

Andy

doxilia

My Feedback: (3)

Nice work and good trick Andy!

It is a useful covering tip which would have served me well when I was covering sport models on a more regular basis (not that I've given up entirely on them - I still have a little "for fun" Shoestring to cover).

Since I started building classics, I've found that it is preferable to basically build the model to completion before applying covering. The reason for this is primarily to allow things like fillets to be produced between surfaces and then pre-cover the junctions (i.e., fillets) before applying the larger pieces. This approach is more tedious and time consuming but it results in models which exhibit less or no "covering junctions".

Of course each model has its preferred approach depending on how it's designed. I've found that Prettner's later models have designs which lend themselves well to "component covering" prior to assembly while models with airfoiled tail surfaces are better covered post assembly.

Looking forward to seeing it finished!

David.

AndyKunz

Good point, David. Knowing when to use the right technique is just as important as knowing the technique!!!

After church today I plan on hinging and installing the surfaces. I will attempt to show another technique or two for that also. (Not for this crowd, but I'm trying to keep this RCU and an RCG thread tied together).

Andy

AndyKunz

Well, it's flyable! The only thing I need to do is attach the main gear doors. Being a holiday, a bunch of the guys from work showed up at the field to get some fun flying in. David Payne had the honors of the first flight, not only because he's great on the sticks but he's also flown a Shrike in the past. I set up the rates on the DX8 to give three range settings for him to get me in the ballpark. After some more tuning flights I will put the finalized throws on the plans.

Unfortunately, my friend wasn't able to keep up with the plane with the camera, so all the pix are on the ground.

If you look closely at the wingtips, you can see I installed LEDs from the E-Flite light kit. They aren't visible in normal daylight when flying If I'm ever up at dusk (not likely with a hot rod like this!) they may help. Otherwise, they're just for the "cool factor."

First flight was 5 minutes on 2200 mAH 3S 30C Thunder Power cells (E-Flite Power 10 with APC 8x8E). When I took it over to the charger, it was still at 45%, so I put another 2 minutes on the timer for the next flight.

Shortly after he landed, a cold front came through with some heavy rain, so I packed it up and came home so I could post these.

Andy

AndyKunz

Somebody on RCG asked about the nose gear door. Here's what I told him:

The door is simply cut out. The bottom of the fuse is curved there, so the door itself is curved but the hinge is tape only on the back half. There are 1/4" sq front and rear. The front one rubs against the side of the gear leg as it drops, pushing it all the way open. There is a short piece of string CA'd to the inside fuse about the height of the retracted leg, and to the door at the bottom (when open) edge. As the leg retracts, it contacts the string and pulls the door closed. Super simple! (Things work best that way).

The main doors will simply be attached directly to the legs. Attached are some stills.

A video of them operating is here: http://www.montanadesign.com/planes/...e/dscf7903.avi

The tape was just something we did real quick at the field. The concept works great, I just need to clean it up a little.

Andy

doxilia

My Feedback: (3)

Cool little Shrike Andy!

Where, if anywhere, do you let air in to cool the motor? The front end looks nice and smooth!

Did you make your gear doors in glass or wood?

David.

AndyKunz

Thanks, David.

There is a NACA inlet on the bottom of the nose, and there's a good opening at the nose ring. Air comes in there, goes around the motor, passes through the firewall into a tunnel above the nose gear where it hits the ESC, then exits behind the battery hatch.

It's all wood. No glass anywhere in it, other than the DB pushrods (which only pass through 3 of 7 ribs per panel).

Andy

AndyKunz

I have a 40-size kit now. When I build it, it will get rudders. DP was trying to correct on landing but it wouldn't yaw. Kinda funny. I was expecting the short wheelbase to be a problem but it wasn't. There's two degrees on toe-in on the mains and with 20% expo on the rudder (nose gear only). It turns on a dime if you want it to, but it tracks really straight on t/o and landing.

Andy

Whaleflyer

My Feedback: (6)

Andy,

Do you have some hidden source on where to find these birds at??