FW Models ASW-17 is here!

[tewatson]

Three of us in SoCal recently received our FW Models ASW-17 racers. 1/3 scale, 6.6 meter span, airfoil optimized for GPS Triangle competition. Two ballast tubes in each wing. Ordered it without linkages or wiring, so everything can be set up exactly as desired. The molding, paint work and parts fit is outstanding...some of the best I have ever seen.

I will be using PowerBox equipment for battery and servo management, dual redundant JR DMSS RXs, and a JR/DeeForce T14X4 radio (same as JR XG-14.) Looking forward to getting this one on the GPS course.

[ARUP]

Nice! Did you get this from the Florida distributor?

[tewatson]

No, we ordered direct from FW Models.

[yyz]

Anyone interested in doing a group buy to split shipping/import costs like Tom and crew did?

Mike

[airporter]

Any estimate on the cost with shipping to the USA but before shipping to a location in the USA?

[tewatson]

Cost to ship three planes to a SoCal freight terminal, plus customs/duty fees, was about $1,400. Airframe cost is going to depend on how many are purchased and what sort of discount you can negotiate.

Model info is here, along with a link to the price list: https://www.fw-models.de/content/modelle/asw17.php

[tewatson]

Update - with the December loss of my JS-1, found myself without a flyable GPS racer. So, immediately started serious work on the ASW-17 with a goal of having it ready for the April 2020 Visalia monthly aerotow. This build presents a couple new (to me) challenges - first scale ship without OEM-designed/installed wing surface linkages, and first time retrofitting a rudder pushrod setup (I hate pull-pull.)

The airframe was specified and delivered empty, literally. No servo mounts, no preinstalled linkages, no preinstalled tow release, no wiring. After the JS-1 wing debacle, wanted complete freedom to design and install things my way. In hindsight, I should have ordered it built with a rudder pushrod...pretty much a pain to install afterwards in a completed airframe. Canopy, retract unit and rudder are OEM-fitted. More to follow...

[Rjtw]

Hi Tom,
Consider it an opportunity -- the wing is still untouched, aerodynamically as perfect as it can be, and you have options! Have you thought about LDS on the wing, and potentially even the rudder? I did all-internal wing linkages on my Hmodel Arcus (same thing, no linkages of any kind installed) and it has worked out flawlessly. There are a lot of more or less ready-to-go LDS systems out there nowadays and most have the added benefit of an external bearing supporting the servo arm. I compiled a list a while back: https://www.rcgroups.com/forums/show...nd-LDS-systems

I especially like the MKS and the Baudis systems. The Baudis system is particularly attractive for large scale with aluminum control surface horns and aluminum pushrods (strong). Or go with MKS and, if you have really huge flaps, maybe use two of the MKS units on each flap but one everywhere else. The Servorahmen unit for the HV747 might be perfect for large flaps as well. That thread also has a link to an all-aluminum frame the DS guys have been using that's good past 500 mph!!

Whichever way you go, let us know, would love to see another one of your build logs!

PS sorry to hear about the loss of the JS-1 :-( What happened?

[Stew2]

Rjtw - Have you fit the Baudis system to any other airframe than an Antares? I looked at doing that a couple of times and the linkages are so engineered specifically for the Antares I couldn't convince myself that it would work with any other airfoil and servo hatch locations than those of the Antares. If you have an different install, please share some photos, it is an outstanding control system for sure!!

[Rjtw]

Hi Stew,
Sorry for the slow reply. Baudis seems to be using their LDS in a bunch of their models now, but the catch is that I don't know if they actually sell their LDS system separately. If I were doing a new LDS install on another airframe I'd check with Baudis first thing for sure. Baudis is hitting it out of the park nowadays... I recently saw a GP-15 with this system installed. SWEET!!!

[tewatson]

I started the build in mid-late December and really focused (well, as much as time allowed with some real work commitments.) At this point, all the servo and linkage installs are complete except for the tow release. I just need to post some details on the various efforts, and wiring is next.

Lost the JS-1 to a total rookie mistake - looked away for a few seconds and re-acquired the wrong plane. It went in hard. I have never seen such utter destruction in a model crash, everything was just completely pulverized. What was left fit into two trash bags and the only thing usable is Axel's hat (which had the top of his head inside when we found it.)

[Rjtw]

Oh no!! That can happen to any of us. That's really shocking that so little was left :-(

I'll definitely look forward to your further reports on the ASW 17! Beautiful model!

[lenb]

Hi Tom, Sorry about the loss of the JS1, that sucks. See it happen a bunch off times and almost was a victim of it myself. We were flying in a gaggle one time back in 2011, I was flying an HKM Asw28, I looked away and then started flying the wrong plane. It had to be a full minute before I realized the plane was not doing exactly what I thought it should. Panic sets in, I pull up hard and out of the corner of my eye I see the plane just about to impact a swamp as it pulls out just in time. I actually BENT the solid wing rod. I took up an hour to get the wing rod out of the plane.

Ugh.

len

[tewatson]

Yeah, it was probably almost two minutes before I realized what was going on. The plane I was tracking just happened to be going where I intended to fly the JS-1. When it finally stopped responding, thought it was a flyaway until it coasted by at low altitude. Then I realized it was the wrong plane. Mine had gone in long before that and it went in so fast nobody really had a chance to call out.

[tewatson]

One other thing I did with this build was to improve on the hardware supplied with servo frames these days. Used bearing support frames for the wing and stab servos, but wanted better serviceability. See thread here: https://forum.scalesoaring.com/forum...ounting-screws

[tewatson]

OK - time to continue with the build. Since it was delivered empty, all the details of fitting it out are up to the builder. Decided to go with an under-nose tow release for three reasons. First, the nose was untouched (and already painted with the anti-collision scheme), so cutting it off and having to refinish the area did not appeal to me. Second, it allows for a more remote servo install. Third, it preserves the option to install an FES, which I don't see myself doing but a subsequent owner might.

First need was to settle on a design. There are several ways to go...I chose a wider footprint to spread the load (and potential shocks during those infrequent tow mishaps) across a larger area. May be overkill, who knows. It's how I roll.

Basic materials are 3mm stainless rod, a short length of 5/32" brass tube (fits the rod well, but not tightly), and some birch ply. Used a 5/32" double-cut bur in my trusty Dremel with router cap, run against a ply fence temporarily fastened to the raw stock, to cut a half-diameter slot for the brass tube. I thought of just gluing the whole mess together, but instead opted to just epoxy the tube in the slot (top and bottom), then fastened the halves with socket screws. This way, if it ever needs to come apart some judiciously applied local heat should allow disassembly. The tow loop slot is angled forward about 45 degrees so the loop material is not continuously stressed against a 90 degree corner under load.

After contouring the bottom side of the block and ensuring proper positioning, glued it in place using MGS epoxy mixed with milled glass fibers and silica. Having the release rod in place while it cured verified proper alignment. After curing, used the slot in the block as a guide to drill down through the lower fuse, then used small files to fully match it to the block. Finally, made up a servo mounting block with brackets and secured the servo. Mounting the servo further away from the release block allows one to avoid using some sort of flexible link to the rod, to account for the vertical displacement resulting from the servo arm arc. The more distance between the two, the less impactful the arc is. Used a 3mm clevis JB-Welded to the rod.

[tewatson]

While we're up front, a word about mounting the PowerBox unit... Although it seemed the tow release rod was going to complicate things, it really didn't. Decided to position it as close to the tow release as possible while also considering battery tray placement. Went with a transverse orientation, which kept the mounting relatively simple AND positioned it above the tow release rod.

First, mocked up the arrangement with some soft balsa rails (easy to shape and try different things). Once the position was defined, needed to fashion ply rails but the idea of holding the PowerBox right up to the belt sander while shaping the material was a non-starter. I fashioned a thin ply plate with the PowerBox bolt pattern to mount the rails on while shaping them, so no damage worries. Once shaped, mounted the rails to the PowerBox and glued it to the fuse with the ubiquitous MGS epoxy, milled glass and silica mix.

BTW, all of the ply components in the cockpit area were sealed before installation with two applications of Watco Wipe-On poly, which keeps the wood clean. Poached the idea from my pal Steve Condon.

[tewatson]

Next is the rudder servo. The plane was designed for pull-pull, and I hate pull-pull. HATE. IT. Installed a carbon pushrod instead, which also allows moving the servo forward, where one can easily access it when needed. The rest of the job was pretty standard stuff. Secured clevises to each end of the pushrod with JB Weld.

Pushrod installation problems were basically limited to properly securing it along the length of the boom. Covered that and related development of the Reachinator in another thread here: https://forum.scalesoaring.com/forum...rudder-pushrod