Prather QM Little Toni build thread - Page 3 - RC Groups
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Mar 14, 2012, 02:07 AM
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I purchased this (edit: Prather Products Micro Balloons) back in the 70's too and it seems like I used a ton of it... lasts forever. Some of this has to find its way into the Toni!!
Last edited by rjtw; Mar 14, 2012 at 04:09 PM.
Mar 14, 2012, 02:11 PM
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Litl Toni

I bought about 6 months ago a toni kit from ebay , and i must admit reading your thread makes me want to put all asid and start this model right now

you have hands of gold, and i envy your building skills

i wish i could build this model with your grace

keep these posts coming, and if anyone has the F1 toni plans and instructions, i would be happy to receive a copy as mine were missing from the kit

i plan to fit a rossi 40 F1 rear intake rear exhaust to mine with tuned pipe

i am watching this thread closely
Mar 14, 2012, 04:17 PM
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Thanks Izzy, I really appreciate the feedback. Dust off that Toni kit and get going, you'll be so glad you did!! Until last year I was out of the hobby for the better part of 30 years(!!) and, apart from finishing up an old leftover project, this is the first build I've done since then. The goal of the project is to build the best I can but to enjoy every step of the way. I had almost forgotten how much fun this is... when I'm in front of that workbench I forget the rest of the world. I've found it to be a great stress reliever!
Last edited by rjtw; Mar 14, 2012 at 05:15 PM.
Mar 14, 2012, 05:08 PM
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Tery Prather

I found this image over at: (Thanks to Napoleon for posting this)

Here's the man, Terry himself, with one of his beautiful machines. I really admire how he turned his hobby into a business, and was very successful at both. Here we see him being pilot, pit crew, team manager and salesman all at the same time. I love how he's put together a brand image, right down to a kind of uniform, with matching airplane and flight box. (And is that a Prather Panther logo on his shirt?) Cool!

I understand Terry sold off the last of his business circa 2007. Anybody know what he's up to nowadays? Hopefully enjoying a nice retirement!!
Mar 14, 2012, 05:51 PM
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Rick hi
i couldnt agree with you more
when i hit the work bench , my wife thinks i am off to my lover
can't get me away from it,
i also haven't build for a long time, and bought a hot kanary bipe kit and just finished building it
i was happy with the way it came out, but could have done much more , so that is why i envy people like you who have a " real carpenters" gift

in any case before i can pull out the kit, i need the plans and instructions- need distances for wing/ ailerons , cg etc

hope someone here reads this and can send me

Mar 14, 2012, 06:05 PM
Registered User
I'll be happy to email you the QM plans and instructions as the designs are very similar. PM me your email address if you're interested. You might also check over at the Fuel - Pylon forum on this site.
Mar 19, 2012, 01:09 AM
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Installing torque rods

Busy week outside the workshop, but got in an hour or two here and there to get the torque rods installed.

I went back and re-soldered the brass pieces to be at right angles to the rods themselves. I plan to use ball links on these later, and the ball will stand off its attachment point at the top of each brass piece by perhaps 1/8". Keeping things at right angles means the ball link will still be centered over the rod and thus the hinge axis -- so I don't build in differential. This will be especially important as I'll be using only a single aileron servo. If I need to adjust differential later, I'll have to do it at the servo arm.

Terry calls for first epoxying the wing halves together, then snapping off the center section of the trailing edge that remained after cutting out the ailerons. The center section is to be removed as a single piece, cut to allow clearance for the torque rods, and reinstalled. But it's difficult as it is to deal with cutting those torque rod channels without also having to work with an odd-shaped piece, plus getting that off and on as a single unit AND back on in proper alignment is a bit too challenging for me. There's no magic in the workshop -- you can get almost anything done with our model airplanes with a relatively small set of good basic tools, and the rest, at least for me, is dividing up and planning out the construction steps to make each step relatively small and as straightforward as possible. The more complex it is, the more I'm likely to make a mistake!

So, I decided to work on each wing separately before joining. A channel must be carved out to accept the torque rods after snapping off the little stub TE on each side. I didn't seem to have an appropriate tool to carve a channel so I used a piece of brass tube I had lying around that was just a bit larger in outside diameter than the torque rod's outer sleeve tube itself. I used my bench grinder to sharpen the end. I then marked the center of both the aileron stubs and of the TE of the wing, held the tube at an angle and very carefully twisted the tube back and forth while moving down the centerline about a centimeter at a time. I then did a little touchup with some 220 paper to remove a few remaining strands of balsa. Finally, I used a small 1/8" circular file to remove material where the rods exit the center section of the wing and give clearance for about 40 or 45 degrees of travel each way on the rods themselves (which is more than the ailerons will move!)

About the only critical operation in installing the torque rods is to ensure that they align properly with the aileron hinge line. It has to line up so that the rod is co-linear with the hinge line both viewed from above and viewed from behind. I first tacked down the aluminum sleeve of the rod with quick CA, and after ensuring proper alignment, I coated the sleeve with slow-set CA up though about 1/4" of each end, and also gave a thin coat to the balsa-to-balsa contact points, then pushed into place. Because I had previously tack-glued the aileron center section on and then snapped it off, the pieces pretty much aligned themselves. The trick is to make sure the channel you carve is big enough to not get in the way, but not so big that it won't hold the roque rod sleeve snugly in place!
Mar 19, 2012, 01:42 AM
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Joined the wings

I was concerned about how best to make the cutouts in the center section of the wing for the landing gear and aileron servo. I knew that once I joined the wing, I would lose a ready reference to the centerline of the airfoil (useful to make the landing gear plate parallel to the airflow!!) and I was also worried about having to hack through dried epoxy in the middle joint. But on the other hand, unless the wing is joined, how can you cut a straight line that crosses through the center section?

I ended up with a kind of compromise that, while I wouldn't recommend to anybody, and is really more work than it needs, seems to have worked out for me this once. I've not tried this before so this was as much an experiment as a challenge to myself to see if I could make it work.

Before I joined the wing halves, I carefully placed them together in their final configuration (top of wing flat). Having previously chosen my aileron servo location as the aft-most point at which the servo could fit in the wing and still just clear the bottom sheeting, I marked out in light pencil the L and R sides of the servo cutout. I did the same thing on the bottom of the wing, tracing around the landing gear plywood mounting base supplied in the kit.

I then carefully sawed through the sheeting and foam (both cuts go all the way to, but not through, the opposite sheeting) after having marked in cross section the exact angle of the cut. For instance, on the landing gear, the cuts are vertical (right angles to centerline of airfoil) but on the servo the cuts are at right angles to the top sheeting, because the servo will sit on top of the top sheeting both fore and aft. I only made the cuts, though, and did not actually remove the cut-out foam and balsa because I was worried that I might change the wing or sheeting shape if I did -- I figured that once the center section is glued and somewhat firmed up, it would be safe to remove later.

Last night I finally epoxied the wings together, making sure to both line up all my cutlines (they appear to have all lined up!!) and also ensuring the leading and trailing edges all line up. I did not spready epoxy on any of the areas that will be removed. Next step is to remove and clean up the cutout areas!

Finally, an interesting note about the wing joining operation itself. With foam wings, at least those that I've always been familiar with that are cut with templates and a hotwire by hand, the left and right halves are never quite identical. I discovered along the way that this was true here, as well, and that there's just enough difference in the root sections to leave a bit of question as to how best to align the halves. There's a slight difference in high-point thickness as well as the angle leading down to the leading edge from the high point. (I noticed this with the cores too, and took some gentle corrections with the bare foam, but thought it best not to try any more aggressive corrections especially with the strange curves on these wings!!) I took the best compromise I could... hopefully it won't take much (or any!!) correction in the air.
Last edited by rjtw; Mar 19, 2012 at 01:59 AM.
Mar 19, 2012, 09:29 PM
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I'm looking forward to seeing this one done. I have a couple old QM15 kits that I have stashed away, keep thinking maybe some day I'll build them. A Folkerts and a Polekitty (Polecat).
Mar 21, 2012, 01:31 AM
Registered User
That would be great. I'm not familiar with the Folkerts at all -- do you have any pictures? These QM15 airplanes seem perfect for today's powerful electric motors and lightweight radios. I used to have a rule of thumb that 2 servos, a 4-cell nicad and the receiver would weigh about 8 ounces. With electric, we'd be looking at about 3 ounces or less for the same thing, assuming battery power from the LiPo. I'm really looking forward to seeing how the power to weight ratio is going to compare to the classic QM15s but we have to be right up there -- especially seeing as how I'll be using an electric motor really more suitable for the larger F1 airplanes
Last edited by rjtw; Mar 21, 2012 at 01:56 AM.
Mar 21, 2012, 01:52 AM
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Landing gear

After joining the wings, time to move on to the landing gear. After getting this part finished up, getting the aileron servo mounting area prepared, and hinging the ailerons, I'll be just about ready to glass the center section, then glass the entire wing. I think that will be one of the most important milestones of the entire project. Hmmm, now that I think about it, I'll have to glass the tail surfaces too... wonder if I want to have the tail ready to go about the same time as the wing.

Terry calls for cutting out a patch of bottom center sheeting to sink in a 1/8" ply plate, provided in the kit, then sinking in some dowels from above to really provide support. I was really worried about the exact shape of the cutout to use, and Terry doesn't explain, but I decided to trust Terry's trapezoidal shape and ended up just tracing around it but adding 1/8" total on the aft side to provide extra space for lining the cutout with plywood as Fizzwater suggested (which is a great idea -- thanks!!) I left extra because I wanted to line the front side with 1/16" ply as well, and also want to complete the box with 1/64th ply on left and right sides. Later, I may want to add a little additional triangular-shaped filler at the bottom corners to fill the small void under the base of each gear leg (see last photo). Terry's trapezoidal shape is virtually perfect though -- it provides just the right amount of clearance around the gear, allowing for both the angle of the gear and the shape of the airfoil.

The photos below show the dry fit of all the pieces. The main plate fits in snug, and after making a few adjustments to check that the main gear was level (using a bubble level across the gear legs) and square, I marked the fore and aft plates with horizontal lines so I know where the main plate should end up during gluing. Next step will be to glue them all in, along with a big puddle of epoxy under that plywood plate
Last edited by rjtw; Mar 21, 2012 at 01:58 AM.
Mar 21, 2012, 02:05 AM
Registered User
Fizzwater, here's another little treasure I have stashed away that might make a great electric conversion too...
Mar 21, 2012, 11:39 AM
Registered User
Rick hi
After watching this thread , i could not wait any longer and decided to start my Toni 40
so with that i started the joining the wing skins
now for the tricky part - need your suggestion :
option 1 - use microglass on the inside between skin and foam
option2 - use microglass on the inside between skin and foam and also strip of unilateral carbon tow ( aprox 1.5 cm wide )

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