Cessna 152, Balsa 30% Scale Rescue from Hostetler Plans
- Thread starter Joker 53150
- Start date
Nope, regular size can, and the plane is a beast for sure. I pulled out the Mountain Models Lucky ACE to check the motor size for a friend yesterday and it felt like I was working on a UMX!
The original Astro-Hog is a good-sized plane, and it must really increase in size once that second wing is added. When they get to 1/4 scale or bigger it's amazing how fast you run out of space! Before starting back to work on my 27% size L-19 or the 1/3 scale Sopwith Pup my workbench size will need to be addressed. The tricycle gear on the Cessna allows me to rotate the plane on the bench (although the tail hangs WAY over the edge), but the other two planes are tail-draggers which limits how I can place the plane on the bench. A 7' diameter round table would be very handy especially if the top rotated.
As you can see in these pictures, finish sanding has yet to happen. Also, what looks like gaps between the sheets is actually some kind of hard filler, and based on how hard it is to cut I wouldn't be surprised if it were some kind of epoxy.
Before doing the final sanding and covering I had to take a step back and make an area to hide the power, ignition, and light switches. I could simply mount the switches inside one of the doors, but that's less convenient than I'd like once the wings are attached. The option I'm going with is making a "luggage door" which is simply a small door meant to load/unload luggage from the plane. I don't think the Cessna 150/152 actually had this, but other versions did and my name isn't Joshua so the scale detail isn't that big of a deal!
First step was determining size and location.
A little happy-time with the knife left a big hole in the side of the plane. But is that the other side of the fuselage you can see? Nope, just an odd design quirk found on many Hostetler plans!
The fuselage is basically a box inside a box. The inner box is a simple structure with flat sides and the outer box gives you the nice curves. My L-19 from Hostetler is designed like this as well - it's very durable. So basically I'm going to use a quirk of the design to keep my switches hidden. The door to access the switches will either be held on by magnets or a hinged side, I'm not sure which yet.
The hole is getting sides, a top & a bottom which will give me plenty of room inside for multiple switches.
Also, what looks like gaps between the sheets is actually some kind of hard filler, and based on how hard it is to cut I wouldn't be surprised if it were some kind of epoxy.Before doing the final sanding and covering I had to take a step back and make an area to hide the power, ignition, and light switches. I could simply mount the switches inside one of the doors, but that's less convenient than I'd like once the wings are attached. The option I'm going with is making a "luggage door" which is simply a small door meant to load/unload luggage from the plane. I don't think the Cessna 150/152 actually had this, but other versions did and my name isn't Joshua so the scale detail isn't that big of a deal!
First step was determining size and location.
A little happy-time with the knife left a big hole in the side of the plane. But is that the other side of the fuselage you can see? Nope, just an odd design quirk found on many Hostetler plans!
The fuselage is basically a box inside a box. The inner box is a simple structure with flat sides and the outer box gives you the nice curves. My L-19 from Hostetler is designed like this as well - it's very durable. So basically I'm going to use a quirk of the design to keep my switches hidden. The door to access the switches will either be held on by magnets or a hinged side, I'm not sure which yet.
The hole is getting sides, a top & a bottom which will give me plenty of room inside for multiple switches.
Noooo! 152s don't have baggage doors! REEEEEEEEEE
Now that that's out of my system, that's a pretty good solution to keep things tucked away nicely.
Now that that's out of my system, that's a pretty good solution to keep things tucked away nicely.
Tench745
Master member
I seem to recall a C150 Aerobat at out local EAA that had a luggage door on the starboard side, much like you're adding. Google doesn't give any indication of others with this door though, so it might have been a modification for that plane.
They'd installed an auxiliary fuel tank in there for some reason. They had also added Leading edge cuffs. Those combined with the aux fuel tank made it so it was no longer rated for aerobatics. Shame really.
Correction: It was a 152 Aerobat, original yellow checkerboard paint. I believe they swapped to a higher horsepower engine as well.
They'd installed an auxiliary fuel tank in there for some reason. They had also added Leading edge cuffs. Those combined with the aux fuel tank made it so it was no longer rated for aerobatics. Shame really.
Correction: It was a 152 Aerobat, original yellow checkerboard paint. I believe they swapped to a higher horsepower engine as well.
Last edited:
PsyBorg
Wake up! Time to fly!
The original Astro-Hog is a good-sized plane, and it must really increase in size once that second wing is added. When they get to 1/4 scale or bigger it's amazing how fast you run out of space! Before starting back to work on my 27% size L-19 or the 1/3 scale Sopwith Pup my workbench size will need to be addressed. The tricycle gear on the Cessna allows me to rotate the plane on the bench (although the tail hangs WAY over the edge), but the other two planes are tail-draggers which limits how I can place the plane on the bench. A 7' diameter round table would be very handy especially if the top rotated.
It would not take a whole lot of effort to make your own "Lazy Susan" for your build table. A central bearing plate with three adjustable arms to hold the planes would be quite east to do. Just take a peak inside your micro wave at the plate mechanism for a starter idea. those plastic rings with three or four wheels attached along with an diameter "Plate" that had slots for these wheels routed out would make a stable mount for the arms. It could be made non permanent too so you still have full use of your build table as needed.
I had hoped to find a better method, but any other hatch would be more obvious and this was easy to explain away as 99% people who will see the plane have no idea the originals don't have luggage doors. I'll just say "Let me open the luggage door and turn power on" and they'll assume it's scale!
The "box" is done, other than running wires and switches to it that is. A little filler around the edges evens it all out and tomorrow it can be sanded flush. Some inner structure will be needed to hold the door in place as well.
From a few feet away and under the trailing edge of the wing this box should be fairly invisible (hopefully). I'm still debating hinging it or making it removable. Each method has it's good and bad sides, but I'm leaning towards a simple removable cover. Hinging would be more scale (on a part that's not scale), but it would be harder to repair if/when I accidentally damage the hatch in the future. Hinging would keep the part with the plane so it's unlikely to lose it, but hinging it may also keep the door flapping in the breeze and getting in my way on a windy day. Oh the choices...!
Back a few hours I was whining about cutting the electrical box and how it seemed like cutting epoxy - well, I just looked at the back of the sheet I removed and it looks like I was right! The guy who built the plane beveled the edges of the sheet and painted the back with epoxy to hold it all together. Not quite how I'd do it, but the seams have held nicely for years. He also had unsupported seams which is a little odd as well - normally it's easiest to butt the sheets together over some kind of structure so you can pin it while glue dries. Either way his method held up.
From a few feet away and under the trailing edge of the wing this box should be fairly invisible (hopefully). I'm still debating hinging it or making it removable. Each method has it's good and bad sides, but I'm leaning towards a simple removable cover. Hinging would be more scale (on a part that's not scale), but it would be harder to repair if/when I accidentally damage the hatch in the future. Hinging would keep the part with the plane so it's unlikely to lose it, but hinging it may also keep the door flapping in the breeze and getting in my way on a windy day. Oh the choices...!
Back a few hours I was whining about cutting the electrical box and how it seemed like cutting epoxy - well, I just looked at the back of the sheet I removed and it looks like I was right!
The guy who built the plane beveled the edges of the sheet and painted the back with epoxy to hold it all together. Not quite how I'd do it, but the seams have held nicely for years. He also had unsupported seams which is a little odd as well - normally it's easiest to butt the sheets together over some kind of structure so you can pin it while glue dries. Either way his method held up.
Not a huge update today, but still a step towards completion. Some inner jambs were added around the inside of the switch box for the door to close against. The filler around the opening now gives me a nice smooth finish almost ready for covering. The final sanding should be quick & easy.
Test fitting the door. I'm expecting it to need more sanding around the edges once the covering is added so I'm not going nuts trying to get perfect gaps on it yet. Covering takes up more room than you'd expect... I'm also starting to lean towards hinging the door along the front (right side) edge now instead of making it completely removable. The trick is just trying to decide what type of hinges to use and how to mount them, so the whole idea is subject to change!
Test fitting the door. I'm expecting it to need more sanding around the edges once the covering is added so I'm not going nuts trying to get perfect gaps on it yet. Covering takes up more room than you'd expect... I'm also starting to lean towards hinging the door along the front (right side) edge now instead of making it completely removable. The trick is just trying to decide what type of hinges to use and how to mount them, so the whole idea is subject to change!
I got bored, found two small pinned hinges, and got the door hung. It still needs final size sanding once covering is on, but works great and opens up 180* and doesn’t interfere with the main door. It’s almost as if I know what I’m doing!
I almost had no idea what you meant... not enough sleep I guess!
Battery trays are going in next, and I'm doing one on each side of the plane for 2 batteries per tray. One battery per receiver, one for the ignition module, and one for lights. I don't care for how it's laid out, but there is limited room to work with without adding a whole bunch of structure or re-building the interior which I DON'T want to do! Yet, at least... Receiver and ignition batteries are LiFe and lights are MiNH. Hopefully all the wires can be run cleanly to the switches behind the "luggage door".
Today I stopped by WalMart and picked up a pack of poster board so I could make the front & rear window templates. The plastic sheets are supposed to arrive today, although the UPS tracking number disagrees with that becoming a reality.
The original windscreens were removed and flattened out to make templates for the new pieces. The process I followed was to copy the original as exactly as possible (as they were far better than starting from nothing) and then determine from there if material needed to be added or removed. Once I had made my scribbles on it showing where to add material, and once the excess was removed I used that template as the design for a second and then third template. By #3 I'm happy with overall shape. It overlaps the A pillars by about 1/8" which will give me enough room to glue it securely, and the top sides where it has to wrap around the leading edge of the wing has about 1/32" extra total which gives me a little wiggle room with the plastic sheet (which is much thicker than the poster board).
The rear was done in the same way, although it only took 2 templates before I was happy with the piece. Note the top edge fits into a little groove for a nice detail. Like so many other things on this plane, that'll come back to haunt me soon. The bottom edge will get a final trimming once I have the clear plastic to work with, and again the pillars are overlapped by about 1/8".
If I were building this plane from scratch, or if I knew then what I know now, I'd have created recesses all the way around for the windows as that would give a great final result. Note that the bottom center of the front windscreen now has a bit more curve to it which looks better and will hopefully help keep the windshield from deflecting too much.
....and here's where the recess for the top edge of the rear window is biting me... The right side is fine as the template goes up and overlaps the B pillar. The left side is recessed about 1/8" too far meaning the window has to make bridge a gap. I didn't notice this during the construction or it would have been fixed, so now I'll have to expend a little effort to make it work. It won't be perfect but it won't be noticed unless somebody is looking from this angle at those corners.
The original windscreens were removed and flattened out to make templates for the new pieces. The process I followed was to copy the original as exactly as possible (as they were far better than starting from nothing) and then determine from there if material needed to be added or removed. Once I had made my scribbles on it showing where to add material, and once the excess was removed I used that template as the design for a second and then third template. By #3 I'm happy with overall shape. It overlaps the A pillars by about 1/8" which will give me enough room to glue it securely, and the top sides where it has to wrap around the leading edge of the wing has about 1/32" extra total which gives me a little wiggle room with the plastic sheet (which is much thicker than the poster board).
The rear was done in the same way, although it only took 2 templates before I was happy with the piece. Note the top edge fits into a little groove for a nice detail. Like so many other things on this plane, that'll come back to haunt me soon. The bottom edge will get a final trimming once I have the clear plastic to work with, and again the pillars are overlapped by about 1/8".
If I were building this plane from scratch, or if I knew then what I know now, I'd have created recesses all the way around for the windows as that would give a great final result. Note that the bottom center of the front windscreen now has a bit more curve to it which looks better and will hopefully help keep the windshield from deflecting too much.
....and here's where the recess for the top edge of the rear window is biting me... The right side is fine as the template goes up and overlaps the B pillar. The left side is recessed about 1/8" too far meaning the window has to make bridge a gap. I didn't notice this during the construction or it would have been fixed, so now I'll have to expend a little effort to make it work. It won't be perfect but it won't be noticed unless somebody is looking from this angle at those corners.
Insert swears and rants of frustration here.
The rear window issue was bugging me and I wanted to see what it was going to take to fix it, but I also wanted to install the wings again first just to see how noticeable it really would be. Turns out it's very hard to see regardless of flap position, which is good. However.... I found out WHY it's off, and it's due to the construction of the center wing, the spot that was causing me a lot of grief a few months ago! When I rebuilt these pieces I simply used the original parts as templates and didn't compare them against each other. Had I done that I would have noticed the left side is about 1/4" shorter than the right! You can see in this picture with the wings on how the right side is a fairly even transition from wing to fuselage, while the left is not.
I can't leave it as-is since it'll bug me WAY too much, it'll have to be fixed before I continue. Luckily it should be a quick fix although it probably won't change the issue with the window.
Access to the "luggage door" was also checked and it should work out very well. If I were to do it again I may move it back about 1/2" and maybe increase the overall size each direction by 1/2", but the switches going in are very small and I expect it all to fit without issues. The door is far enough forward that it's somewhat hidden from view by the wing. In this shot you can also see why I didn't want to have to open the main door to access switches - they're covered by a metric acre of wing!
The rear window issue was bugging me and I wanted to see what it was going to take to fix it, but I also wanted to install the wings again first just to see how noticeable it really would be. Turns out it's very hard to see regardless of flap position, which is good. However.... I found out WHY it's off, and it's due to the construction of the center wing, the spot that was causing me a lot of grief a few months ago!
When I rebuilt these pieces I simply used the original parts as templates and didn't compare them against each other. Had I done that I would have noticed the left side is about 1/4" shorter than the right! You can see in this picture with the wings on how the right side is a fairly even transition from wing to fuselage, while the left is not.I can't leave it as-is since it'll bug me WAY too much, it'll have to be fixed before I continue. Luckily it should be a quick fix although it probably won't change the issue with the window.
Access to the "luggage door" was also checked and it should work out very well. If I were to do it again I may move it back about 1/2" and maybe increase the overall size each direction by 1/2", but the switches going in are very small and I expect it all to fit without issues. The door is far enough forward that it's somewhat hidden from view by the wing. In this shot you can also see why I didn't want to have to open the main door to access switches - they're covered by a metric acre of wing!
<Sigh>.... When builders give you lemons you make lemon-scented balsa dust.
There is no "easy" fix for the problems I ran into last night with the trailing edge of the wing lining up with the center section on the fuselage. Well, I guess the easy solution would be to simply ignore it all together, but what fun is that? After tearing into it I think I understand (sort of) what the builder was doing.
First up, here's a picture of where I started this mini-adventure. The flap is about 95% up, and you'll notice eaily how the wing doesn't line up with the center-section. There is also a bit too much gap at the trailing edge on the center section, but that's my fault - it's been corrected.
After a little surgery the wing and center section line up, although some final sanding is required once the filler dries. The flap is fully up now, which created yet another problem - the flap hits the new structure! Some of you may have noticed on previous pictures how the flap had a bit of bare balsa showing where a corner was shaved. That was to give clearance for this material I just added. So the builder decided to fix one side by trimming the flap, and then fix the other side by modifying the center section of the wing!
Since I think having symmetry is fairly important I'm modifying the left flap to match the right, and both wings will also line up with the center section. It ain't perfect, but I'm not going back and doing more invasive surgery to do it the way I'd like to. The cut section shown below was just enough cutting to get the flap to close fully. It'll be sanded and evened out for a better appearance when I start sanding the filler. Eventually the flaps and ailerons will be completely rebuilt so I'm not too concerned with cutting them up a bit right now.
There is no "easy" fix for the problems I ran into last night with the trailing edge of the wing lining up with the center section on the fuselage. Well, I guess the easy solution would be to simply ignore it all together, but what fun is that? After tearing into it I think I understand (sort of) what the builder was doing.
First up, here's a picture of where I started this mini-adventure. The flap is about 95% up, and you'll notice eaily how the wing doesn't line up with the center-section. There is also a bit too much gap at the trailing edge on the center section, but that's my fault - it's been corrected.
After a little surgery the wing and center section line up, although some final sanding is required once the filler dries. The flap is fully up now, which created yet another problem - the flap hits the new structure! Some of you may have noticed on previous pictures how the flap had a bit of bare balsa showing where a corner was shaved. That was to give clearance for this material I just added. So the builder decided to fix one side by trimming the flap, and then fix the other side by modifying the center section of the wing!
Since I think having symmetry is fairly important I'm modifying the left flap to match the right, and both wings will also line up with the center section. It ain't perfect, but I'm not going back and doing more invasive surgery to do it the way I'd like to. The cut section shown below was just enough cutting to get the flap to close fully. It'll be sanded and evened out for a better appearance when I start sanding the filler. Eventually the flaps and ailerons will be completely rebuilt so I'm not too concerned with cutting them up a bit right now.
The common claim is that the most likely thing to fail on an IC plane is the power switch. If the switch fails the plane crashes, fairly simple math. To combat the problem a second switch can be added and wired parallel to the first one. This way, if either switch fails the system isn't compromised. As shown earlier, I made a small switch cabinet to hide the switches while keeping them easily accessible. Four circuits total (Receiver 1, Receiver 2, Ignition, Lights) and 2 switches per circuit and it all fits. Switch forward is OFF, switch back is ON as with all the other switches on my planes.
White = Left side of plane / Receiver #1
Red = Right side of plane / Receiver #2
Green is for Ignition
Yellow is for Lights
A little fabrication needs to be done to space the switch panel still, happening tomorrow.
Soldering up all the connections took a little time, but all switches work as planned. I'll add a little liquid electrical tape just to be safe since these switches will be carrying voltage straight from multiple batteries and I'd hate to accidentally short between batteries!
White = Left side of plane / Receiver #1
Red = Right side of plane / Receiver #2
Green is for Ignition
Yellow is for Lights
A little fabrication needs to be done to space the switch panel still, happening tomorrow.
Soldering up all the connections took a little time, but all switches work as planned. I'll add a little liquid electrical tape just to be safe since these switches will be carrying voltage straight from multiple batteries and I'd hate to accidentally short between batteries!
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