Cessna 152, Balsa 30% Scale Rescue from Hostetler Plans

[Joker 53150]

Good thing I'm not afraid of a soldering iron! A couple hours this morning were spent putting together a wiring loom to keep everything as tidy as possible. The harness is being designed to connect two batteries on the left with two batteries on the right, running them all through the switch panel. So far I've finished and tested the harnesses to power the receivers and next will tackle the rest of the harness for the ignition and light circuit.




It's still a bit rough and unfinished, but I'm happy with how it's turning out. Powering up the plane is done by simply flipping switches from top to bottom in order as needed.

 

[Joker 53150]

The massive wiring harness is done - it took much longer than expected, but it all works as planned and it's relatively neat & tidy. Well, as neat & tidy as it can be considering how much wire is stuffed inside a fuselage that wasn't laid out for it.

During all the wiring something was bugging me regarding the wingtip strobes. When the system is in operation you can easily hear it "snap" as it discharges to flash the lights. They aren't simple LEDs, but some kind of glass tube. My concern is that the voltage could cause interference and kill reception. This was confirmed when I hooked everything up and tested it today. Even with the harnesses for the lights separated as far as possible from the control surface harnesses the ailerons would twitch with each strobe of the lights.

Crap... Well, I'm not going to risk flying with the strobes in operation so I'll remove the control box. The wiring can stay, as eventually the plan is to install some LED strobes which shouldn't be an issue.

 

[PsyBorg]

Several things I would probably change before flight. I thought this out the other day when you posted you were adding switches but I lost my internet a few days and could not post until now to maybe have you rethink this.

First is toggle switches.. in my head I see these as a potential problem on hard landings. They could be toggled by impact or inertia on a hard landing and possibly shut off power to key systems like the receiver and maybe leave you in a bad way for throttle and steering control. Would be kinda bad when you had to throttle up to avoid a down draft and the plane hits hard and the power to the radio gear is deactivated in a high throttle state, or that the motor kill switch is set and you lose power altogether.

I would swap them out for shorter harder locking rocker types or better yet push button ones.

As for the strobe issue I will bet they are flashed by a timing circuit on a big capacitor to pulse them. I will bet if you changed the wire out to an audio cable with shielding and grounded the shielding properly or maybe put a filter capacitor on the receiver itself you could eliminate that twitching as that huge power spike gets pulsed to fire the strobes.

 

[Joker 53150]

Several things I would probably change before flight. I thought this out the other day when you posted you were adding switches but I lost my internet a few days and could not post until now to maybe have you rethink this.

First is toggle switches.. in my head I see these as a potential problem on hard landings. They could be toggled by impact or inertia on a hard landing and possibly shut off power to key systems like the receiver and maybe leave you in a bad way for throttle and steering control. Would be kinda bad when you had to throttle up to avoid a down draft and the plane hits hard and the power to the radio gear is deactivated in a high throttle state, or that the motor kill switch is set and you lose power altogether.

I would swap them out for shorter harder locking rocker types or better yet push button ones.

As for the strobe issue I will bet they are flashed by a timing circuit on a big capacitor to pulse them. I will bet if you changed the wire out to an audio cable with shielding and grounded the shielding properly or maybe put a filter capacitor on the receiver itself you could eliminate that twitching as that huge power spike gets pulsed to fire the strobes.

The switches have a fairly hard "toggle", so landing hard enough to accidentally turn them off probably means the plane is going to sustain some damage. They're actually much harder to flip than any of the other planes I've got with the fully exposed switches, plus having a second switch for each circuit means BOTH would need to get turned off to lose the circuit.

You're probably right about using some shielding to eliminate the servo twitching, but I'm going to let this part of the plane die for now. It's a cool feature, but those lights will eventually be changed to LEDs when the wings are re-built. My big concern is the power spike causing interference with the plane once it's flying and this has me spooked.

On a different note, I also realized I didn't have enough MonoKote to do the fuselage so an order was placed. Flashing back a few months the original plan was to just re-build the doors so a single 6' long roll was plenty. Then the doorjambs and nose were added, then the rear cabin area, then rear fuselage, then tail feathers... TopFlite sells both 6' and 25' rolls, so I ordered a 25 footer which should be plenty. Doing just the wings later on will require almost 25' as well, which is FAR more covering than I've ever put on a single plane.

 

[Joker 53150]

It looks like it's finally time to start doing some covering. I'm starting with the rudder which was already covered about a month ago. I wasn't very happy with how it turned out previously around the curved top, so I stripped it and re-covered it last night. Just the rudder took over an hour to finish, so I'm guessing the entire tail section will easily keep me busy till the weekend.

 

[wilmracer]

I'm sure you mentioned it somewhere in this thread, but are you keeping the trim scheme the same or doing something else?

 

[Joker 53150]

It'll probably be somewhat close to what it came with, but without all the wrinkles! That design was fairly basic and also a good representation of what full scale 150/152's have. This may be something I need to finalize my plan on soon!

 

[Joker 53150]

Most .40-.60 size planes will take a couple rolls of film (6’ each) to cover. I should burn through a full roll covering a rudder, two doors, and hopefully both elevators. There will be enough scrap left to do a bunch of trim, but not the stabilizers or fuselage. The more I work with the MonoKote the more I like it. It’s not cheap but it should finish nicely.

 

[Joker 53150]

Time to do some trim-work for the covering. All inside corners and areas like door jambs will get some trim added, which simply gives the bigger sheets yet to come a better spot to attach, and it also gives a much neater final appearance. To do the job I'm using my Top Flite trim iron, which is really getting a work-out! It's got a much smaller "foot" than the regular iron and it's got thin edges so it really allows me to get a decent edge.




I did claim the trim will give me a neater final appearance, but in this case it's mainly a neater appearance that'll be visible when the doors are open. Once I finish covering I'll do some before & after pictures to really illustrate what I mean. The outside edges visible here aren't that critical as they'll be covered up soon enough




Lots of trim is needed along the tail as well. When I start covering the large surfaces the edges of the sheet can simply be stuck down to the trim.




Oh, and Amazon claims the shipment of plastic sheet ordered for my windows will be here in the next few days. This order is to replace the first order that never arrived. Hopefully it gets here soon and is thick enough!

 

[nhk750]

Looks good, Im almost ready to use my trim tool too and start trimming.

 

[rockyboy]

I haven't tried this technique of pre-covering the inside joints and tough edges nefore. Will need to remember it for the next covering job. Thanks!

 

[Joker 53150]

I find if VERY useful for the inside corners especially since most of the angles are not 90* and flat. It's far easier than trying to get a single big piece of covering to lie flat or to try and line up two individual sheets at a corner. Tiny gaps should be almost invisible this way. In theory...!

 

[Joker 53150]

Doing the trim work is SLOOOOOOOOOOOOOOW. 90 minutes after work today and all I got covered is the inside of a door and a few other spots on the tail. But as slow and tedious as it is, it'll help me move that much faster when I start using big sheets.

 

[Joker 53150]

Covering is going on, and as predicted this is MUCH faster than doing all the little trim work. Having the trim pieces really makes this job easier as the covering sticks quickly & easily to the trim. As you can see by the reflection in the covering it isn't perfect and there is a little waviness to it, but it's a substantial improvement over the original covering.




The original hope was to cover the tail with 3 pieces - one for the bottom and then one on each side that would meet at the top. However, there was simply too much curve to the fuselage for me to make that happen. I'm sure there are tons of people out there who could have done it, but I'm not one of 'em! By the end of the day today I'm hoping to have the entire fuselage about 3/4 done so I can finish it up over the next few evenings. Then I can decide on a final trim color & pattern.

 

[Joker 53150]

For a color scheme I am leaning hard towards something similar to this. It's got all the flavor of a classic Cessna 150/152 design and will be fairly easy to reproduce. Plus, the colors look good.

 

[nhk750]

Looks great, I'm firing up my iron today too. I like the original paint scheme for yours.

 

[PsyBorg]

So blaze orange base with purple accents and polka dots and lime green numbers is off the table huh....

Looking good mate and I will second the likes of pre-covering inside joints and doing the trim work first like you did.

 

[Ray K]

Nice choice, Joker. She'll be beautiful!

 

[Silverdog]

Love the color scheme you posted. Reminds me of my visits to the Cessna Dealer at Arlington Texas Municipal Airport when I was a kid.

 

[Joker 53150]

It was a long day at work, so to unwind I told my wife I'd only install ONE piece of covering before stopping for the evening.

Well, I didn't mention it was about four square feet in size and would take about an hour... With the first side I used two pieces and ended up with a seam. This is because of the size of the area being covered and the amount of curve in the fuselage. The bigger the piece and the more curve there is, the harder it is to cover and shrink the material evenly. The down-side in using two piece is the seam, which isn't super obvious, but still visible. So with the second side the goal was to do it with one piece and re-do it with two if it didn't work.

First up is cutting an over-sized piece and getting the bottom (overlapping) edge nice and straight. It's then tacked down around the perimeter and as many wrinkles as possible are removed during the process. When I'm happy enough with it all edges are sealed and shrinking can start.




There were some major wrinkles to deal with on top, but with liberal amounts of heat from the heat gun they slowly disappear. The heat gun got such a workout on this build it burned out! I've had it for over 30 years (25 of which were in storage) and it finally gave up.




Heat, heat, and more heat being careful of the edges and eventually it's all nice & tight. Tomorrow I should finish up the vertical and horizontal stabilizers and maybe the B pillar. By the end of the week it should have a full coat of white and then I can start laying out the design. Red MonoKote was ordered today as I found my roll was far too short for a project this size.