My version of the tried and true Hanger Rat, using the standard Horizon Hobby Champ brushed motor (PKZ3516) and receiver/servo "brick" from the Night Vapor (3-Ch Rx/ESC w/LED Port: Night Vapor PKZU1152. And AR6400 could easily be substituted, but I was using what I had on hand and could easily add lights someday).

Many build threads for this plane already exist, so I am not going to repeat at length every detail of the build. You can learn everything you need to know about the classic Hanger Rat and its history at this link: http://www.ctie.monash.edu.au/hargrave/hangar_rat.html. In this Build Log, I will focus on the changes that I made to build something with 3-channel control and that I consider robust enough to survive rough handling and yet still fly gracefully.

The big changes that I made were a basswood fuselage & basswood LE of on the wing; full depth ribs throughout the wing because I wanted a stronger wing and intended to cover with Coverite "Microlite" instead of tissue, and wing rib gussets at both the ends of the wing, just in case I had a hard landing and impacted a wingtip. Also used a basswood rudder instead of the balsa called for in the rubber powered classic Hanger Rat, because I wanted to avoid any warping and have a solid surface to attach my control horns to. Rear struts were mandatory to correct warping in the wing that is inevitable even with the lowest heat setting applying the Microlite. And of course I had to build an elevator for the rear stab, so there is extra wood back there, including basswood sheets for strength and to accept the elevator control horn. My landing gear wire was .32 piano wire and .25 would have been sufficient, and I used some 1" plastic wheels I had lying around and could have made balsa wheels out of two 1/32 sheets glued cross-grain to each other. Finally, I made a basswood cradle for my receiver brick so that I could easily remove it and use it again on another plane if I ever wanted to, and that surely added a bit to the final weight.

All the above amounted to a plane with an AUW of 30 grams! A classic rubber powered, tissue covered Hanger Rat, built well enough to avoid the need for rear struts and with contest grade balsa and tissue could easily be 6.5 to 7 grams, so this is quite heavy by that standard. Still, 30 grams is right on the money for a UMX scale indoor 3 channel plane (and knowing what I know now, I am quite confident that if I rebuilt it, it would have an AUW of no more than 26g). Mine flies slowly enough that I can walk alongside it to trim it out and video it in flight, which you can see me doing at the end of this video:

Hanger Rat: simple electric balsa airplane build and maiden flight (8 min 14 sec)

I will post some build photos with explanations where it might be useful and wrap this build log up in a few days with a set of plans that will show the measurements and CG of my model, which is different from the classic Hanger Rat design. Hopefully this will make your Hanger Rat "E-Ratta" project much less trial and error than mine was, although personally that's a big part of the fun for me. I'm sure this could be made significantly lighter, and if anyone else tries this out, please feel free to post some photos, video and text on this thread so we can all see and benefit. Cheers!

Here then are the plans and photos (I'll start with the balsa building photos - this may take several posts):

Finishing up the parts.

This posts represents three evening building sessions. The whole plane was put together in two lazy Saturdays with 4 hour-long evening building sessions sandwiched between.

Photos taken on the last Saturday build session, before the maiden on the following day: attachment of the wings and struts and of course, the Hanger Rat pilot figure for good luck!

Uploading a set of plans that I re-drew, so that the 1:1 scale Hanger Rat will all fit on a single sheet of 11" x 17" Ledger paper. I added some details from the Max Starick variant, along with tips and clarifications that I used and/or believe will be found helpful.

Update 1/10/19): I just upload the RC "E-Ratta" plans! Go here: https://www.rcgroups.com/forums/show...5&postcount=19

Looks great! Always have loved the hangar rat, just haven't ever gotten around to building one. This makes me think I should get around to it! I need something new to build anyway...
Ross

Thank you, It's now much higher on my to do list.

This plane was like the sherbet that is served between courses in a fine restaurant. A nice palette cleanser in between big, long, complicated scale building projects. Sometimes it's nice to just whip something together in a few afternoons and evenings and go fly it the same week that you started it.

I'm now considering a larger, fully aerobatic 4 channel version running on a brushless 2 cell.

You might be interested in the following article giving some history of the Hangar Rat:
http://www.ctie.monash.edu.au/hargrave/hangar_rat.html

It includes a a picture and brief description of an enlarged version, the King Rat.
Peter

Originally Posted by Altbob

I'm now considering a larger, fully aerobatic 4 channel version running on a brushless 2 cell.

Yeah that will preserve the relaxed easy flying nature of the model

Hi Peter - I actually gave the link to the monash.edu article in my opening post. The link is also in the credits of the video. But the problem with the King Rat is that all the links are dead. And that model is hardly aerobatic or suitable as such with the parasol wing.

Terry, you're right, deleting the dihedral, using a symmetrical airfoil and lowering the wing would give me more of a slow-stick sort of plane, and not so relaxed or easy flying (and I get that you were kidding). I am just toying with the idea, given how I plan to use this with Highschool RC Club students, and having a more advanced version would be a great learning experience for the kids.

I had a lot of success teaching kids to fly with a Falcon Wannabee which was a 3 channel depron and carbon model, then I moved onto a Vapor. I've found that a 3 channel plane is a good way to start, in fact in the early lessons I don't give the student throttle control ( I keep that) its one less thing for the student to think about and they never shut down when they crash .

Good tip, thanks. After they build the standard AMA foam plate gliders, they move on to a rubber powered Hanger Rat, then I will buddy box them on my "E-Ratta." By that time we should be into Spring and can start migrating out of the gym and into the school's soccer field.