Olde School Thermic 50X laser cut RC build [Archive]

lrsudog

Nov 13, 2005, 08:25 PM

I got my grubby hands on one of Tom's (mmartin55) prototype laser cut Thermic 50X kits that was being discussed last week.

Thanks to the USPS, two of the thicker laser cut balsa sheets were cracked (Even though I considered the packaging more than usually adequate), but easily repairable with a bit of thin CyA wicked into the effected parts.

After oggling the plans last night while ruminating what mods I will have to do to make the plane RC, and cleaning off the bench this morning, I started in on the wing. I am starting with constructing the componants that will not be modified for RC, then moving on to the parts that must be altered.

Since there are no instructions beyond those for the old freeflight version, this is a kit that will require a bit of building experience to make RC. It appears to me that anyone with a couple of balsa kits would have no problems in this regard.

Also, If I were building this plane as I wished, rather than beta testing it, I would make further mods to suit my preferences. Next one will get ailerons and a CF laminated main wing spar, even though I estimate that even built as stock it will be plenty strong enough for normal flying. BTW, the plans give the "Contest weight" as 6 oz. which I figure to be substantially under.

mmartin55

Nov 14, 2005, 01:37 AM

Nice work Irsudog!

I was worried about cutting the spars with the dihedral chamfers already in place. Did that help any? I asked Walt to choose a good medium hard for the 1/8" stock for spars and trailing edges and he did a good job. Its kind of a tradeoff having flat stock for the trailing edges since they must be planed and block sanded but then again you have the notches cut to make jigging in the ribs faster and it will produce a much more rigid and robust wing due to the increased glue area. Did you frame them in flat or shape them first?

Have fun...

lrsudog

Nov 14, 2005, 12:47 PM

The kerfs on the spars allowed me to just leave the outer panel digedral break and associated ribs "Unglued" while I framed the wing, then just raise the outer wing panels to the proper dihedral and glue the spar joints, gussets, and ribs without having to actually remove the panels and sand the angle by hand.

As far as the trailing edge flat stock, I built the wings first, then sanded in the TE taper with a sanding block. Anyone who has built a Guillows kit will know how to do the same.

Finished weight of the wing after sanding: 20 grams.

mmartin55

Nov 14, 2005, 06:24 PM

Good, sounds like you did OK! I wish there was an economical way to put tapered stock in the bed of a laser cutter and index it for cutting the notches. We could make hay with that.

Tom

lrsudog

Nov 14, 2005, 11:11 PM

Jasco provided tapered notched TE stock but it was machined. The only way I see to index pre-tapered TE stock would be to affix multiple strips to sticky paper. Hardly worth the effort.

lrsudog

Nov 15, 2005, 01:16 AM

Horizontal stab/ elevator construction. 1 hour. Weight before sanding: 12.4 grams.

Greg L.

Nov 15, 2005, 02:42 AM

Keep it coming, Irsudog. I've got one of these coming as well as one of Toms Laser cut Thermic 50's. On top of that, I've got one of the old Jetco Thermic 50's in the closet that I'll likely snag the TE's from for one of the Laser kits. :cool:

mmartin55

Nov 15, 2005, 10:14 AM

Irsudog, Looks great!

How did I do on fit so far... everything still ok in the stab?

What are your thoughts on flattening the airfoil on the lifting stab so that the CG can be moved forward in the RC version of this aircraft? I would think since the spar is positioned as it is low in the ribs, that one could block sand the surface into a fairly conventional stab airfoil and still use the parts provided which will also allow the olde school build.

I can see most folks wanting to do this,

Tom

lrsudog

Nov 15, 2005, 01:07 PM

I decided for this build to go (Stock) and let the flying characteristics fall as they may. There is a substantial amount of decalage built into the stab mount, so there would be plenty of room to use a thinner semetrical airfoil and allow a finer decalage angle for more neutral flight, and greater speed range. All that would be needed would be a set of half ribs that would be glued on to the bottom of the stab after lifting it off the building board.

OTOH, I have a couple $350 DLGs that have a big speed range and penetrate well in wind. I think this plane is best suited for lazy calm afternoons rather than modifying it to be a "modern" handlaunch.

Glo4U

Nov 16, 2005, 11:22 AM

lrsudog

Nov 16, 2005, 01:16 PM

Do you think you could include a little more detail on the RC mods? I plan to build this version, but stay as stock as possible. I have some ideas on modifing the plane but I want to see what you are doing to compare notes.
I was thinking of using sq stock for the rudder vert. stab. joint and sanding the rudder side to a "V" and using a CA hinge there. And possibly the same on the elevator and Horizontal stab joint. This way allows a maximum amount of movement with the least amount of weight, or along the same line just sand on side of the surface and use hinge tape to give a better aerodynamic flow.
Thank You,
Gloria

For the rudder/vert stab hinge I will be sanding an angle on the rudder as you describe, but I will be hinging it with Blenderm hinge tape after I cover the parts insetad of using CYA hinges.

As far as the mods for the elevator, I added two strips of balsa the thickness of the airfiol at where I wanted the hinge line. You can just make them out in the pics of the horizontal stab. This will allow me to sand in the angle you describe. Again, I plan on hinging these with tape after covered. I will be installing a wire "U" attaching them as is common.

I will take some more pics that should clarify this after I get it completely sanded and seperate out the elevator control surfaces.

I have to take a week long break from the project due to some family stuff, but will wrap up the boom, verticle stab, and fuse/radio install late next week.

Glo4U

Nov 17, 2005, 06:09 PM

Thanks,

Gloria

Have a happy holiday.

lrsudog

Nov 29, 2005, 06:24 PM

Okay! was away from the project a few days more than I had planned, but I got back on it last night.

I have framed up the Fuse and installed the two servos, and will be laminating a tail boom this evening or tomorrow. Lot's of room in the fuse!

I will post pics this weekend for all those interested.

mmartin55

Dec 10, 2005, 08:54 PM

Irsudog.... does it fly?

Thought you might have finished and been having so much fun flying it we would never see the last installment.

Actually, based upon your feedback, I have gone ahead and cut a dozen kits and am heading out to rip a bunch of tight grain fir hardwood stock for booms and kit them all up and start shipping on Monday.

I'll email everyone who has contacted me but if anyone else wants one for under the tree, let me know right away cause I have two dozen quarter scale Hall Cherokees to cut, a dozen quarter scale Piper Pawnees and a two dozen or so 1-23 and 1-26 Schweizers and a proto TG-2 at 62.4" span all to get out the door by Christmas!

Tom

lrsudog

Dec 13, 2005, 10:12 PM

Tom, I am temporarily digital camera-less, but the bird is essentially done, with the excption of a top hatch. I have taken some pix with a film camera and hopefully can convert them this weekend.

Last weekend was windy so no flights yet.

mmartin55

Dec 13, 2005, 10:51 PM

I take it then the fuse pod went together without major hitch. Are you gliding it or guiding it on the maiden? Will it have radio gear installed and turned on?

Tom

lrsudog

Dec 14, 2005, 12:54 PM

Oh yeah. the fuse went together in about half an hour. It took me a while to get my balsa/cf/ply tail boom up to the right thickness, and I replaced the paper clip rubber band retainers with dowels, but neither really presented any need for deep thoughts.

I will definately be controlling it. There is a huge amount of room for radio gear, considering that the pod is four times larger than that on my Photon II.

Total weight with a Berg rx, a 2S 450 Mah lipoly, a voltage regulator, and 2 blue bird servos is right at 3 oz., covered in Japanese tissue, less the hatch I still have to carve. It's so light that I want to wait for dead calm before I toss it around.

CoastalFlyer

Dec 14, 2005, 02:22 PM

Total weight with a Berg rx, a 2S 450 Mah lipoly, a voltage regulator, and 2 blue bird servos is right at 3 oz., covered in Japanese tissue, less the hatch I still have to carve. It's so light that I want to wait for dead calm before I toss it around.Wow - incredibly light. You'll need calm air with that wing loading. My coastal air is rarely calm enough for something that light.

After your initial glide tests do you plan to just hand launch it or are you going to try it on a slope?

Nice build - thanks for sharing.

BTW, digital cameras are dirt cheap right now. Just bought my wife a nice little 4MP Canon for $150! Treat yourself - you can afford it. ;)

lrsudog

Dec 14, 2005, 02:34 PM

Wow - incredibly light. You'll need calm air with that wing loading. My coastal air is rarely calm enough for something that light.

After your initial glide tests do you plan to just hand launch it or are you going to try it on a slope?

Nice build - thanks for sharing.

BTW, digital cameras are dirt cheap right now. Just bought my wife a nice
little 4MP Canon for $150! Treat yourself - you can afford it. ;)

I've built a mini-mini highstart for it from a 25' stretch of 3/16" FAI rubber and 50' of kevlar kite line I had laying around. Similar to what I used to use for my Thermic Trooper FF, but 1/16" bigger rubber.

The camera wait is a direct order from my wife, given the upcoming Christmas gift fest and the fact that she is the one who killed my camera by drowning it.

CoastalFlyer

Dec 14, 2005, 02:45 PM

I've built a mini-mini highstart for it from a 25' stretch of 3/16" FAI rubber and 50' of kevlar kite line I had laying around. Similar to what I used to use for my Thermic Trooper FF, but 1/16" bigger rubber.That should be perfect. I'm using something very similar for a 48" light little HLG I built - works great. Lot's of fun.
The camera wait is a direct order from my wife, given the upcoming Christmas gift fest and the fact that she is the one who killed my camera by drowning it.Understood. ;)

There are some truly amazing camera deals out there. I had a hard time choosing which one for my wife. I think my Aerial Photo plane is going to get a camera upgrade soon.

mmartin55

Dec 14, 2005, 05:45 PM

Oh yeah. the fuse went together in about half an hour....

Glad to hear that. The way you build this sounds like a weekend project, and wow, I expected it would come in at least 10-15 ounces but I guess as little sheets of balsa in the whole kit and that half of those are thrown away after you punch out the parts, plus tissue and sub-micro gear that's awesome!

With spruce substituted for the balsa spars and boom and lightweight film I guess it will come in around 15 oz. and satisfy Coastal's need for speed! A guy could even ballast it up using full size gear with all that room.

Tom

CoastalFlyer

Dec 15, 2005, 11:34 PM

Tom,
Beautiful kit - thanks for making it happen. ;)

Are these listed on your site?

mmartin55

Dec 15, 2005, 11:55 PM

I had them listed but lost the link when I changed pages. Let me fix it and put it up again right now.

The current link is http://www.tmrcsailplanes.com/SAM-vintage-sailplane-kits.html but is not found on the page http://www.tmrcsailplanes.com/tmrc-sailplane-products.html where it should be.

I have a couple left but will get another dozen cut next week or so.

Tom

Greg L.

Dec 19, 2005, 09:50 PM

I've got two of the Laser T-50X's now and was thinking of turning one of them into a powered glider with a folding prop. Any ideas on what electric motor to power it with? :cool:
TIA,
Greg L.

BMatthews

Dec 20, 2005, 01:07 AM

I've got two of the Laser T-50X's now and was thinking of turning one of them into a powered glider with a folding prop. Any ideas on what electric motor to power it with? :cool:
TIA,
Greg L.Something small. No need for big power with something like this. Probably the little GWS IPS motor and gear drive as it comes on the little Lite Stik would work fine. Just need to modify the prop to be a folder. And with the low current the motor draws (2 or 3 amps tops?) you can get away with a 2S1P 430 or 500'ish lipo pack for super light weight.

Greg L.

Dec 20, 2005, 05:11 AM

Something small. No need for big power with something like this. Probably the little GWS IPS motor and gear drive as it comes on the little Lite Stik would work fine. Just need to modify the prop to be a folder. And with the low current the motor draws (2 or 3 amps tops?) you can get away with a 2S1P 430 or 500'ish lipo pack for super light weight.

Thanks, Bruce. I kinda figured it would need something small, but wasn't sure how small. ;)
I was thinking on useing a WESTPORT-DESIGN.COM Brushless CD Rom 20 Turn motor on a Castle Creations Pheonix 10 ESC with a folding prop, but that might be overkill. :eek:

Greg L.

mmartin55

Dec 20, 2005, 09:44 AM

Greg, You might look into one of LensRC motors http://www.lensrc.com/catalog/index.php.

He lives in neighboring Peculiar MO and does a lot to support the local and national electric flight scene. His motors are hand wound Made-in-USA-quality and he can give you all of the data you need and if you like it, I can retail them in orders for the 50-X to make an economical package with the Castle speed control, LensRC motor and battery pack and ship with your second 50-X at no additional shipping. I may even have the motor in stock already.

He's a great guy and deserves your business and it makes sense to prototype his motor on your setup for the above reasons. We can then recommend the right motor with credibility for this application and ship them to our 50-X flyers in the future.

Tom

Greg L.

Dec 20, 2005, 10:59 PM

Thanks for the recomendation, Tom. I'll contact him/them within the next couple days and find out what they suggest.
What would you say the built weight with light weight plastic coverings, RX and servos would be? I'm thinking of going with Blue Bird 303 servos for the T-50's.

Greg

mmartin55

Dec 21, 2005, 09:55 AM

Greg,

I think you can come in under 10 oz. with the materials and radio gear speced if you use the lightest pushrods/housings and battery/motor combination you can find and depending upon whether you add ailerons or not.

Zaic gave 4.75 oz. as all up weight on the plans which we know from Irsudog is achievable, weigh your gear and add that and the total covering based upon manufacturer's speced square foot weight times about 5.5 square feet plus your pushrods and motor/prop and you should have it. The CD Rom motor I have with wires and plugs weighs in just at one ounce and the Phoenix 10 at .21 oz.

Tom

Greg L.

Dec 22, 2005, 12:09 AM

Hey, Tom;
I was thinking of going with Castle Creations Thunderbird 9 ESC, Blue Bird 303 servos, Dubro 20" Micro Pushrods and control horns. Just have to look out for light weight RX and motor. Was thinking of covering with Coverite Microlite covering. I'm planing on a straight 3 channel setup, r/e/t. :cool: Oh yea, almost forgot, 2s lipos and a micro switch.

Greg

mmartin55

Dec 22, 2005, 01:40 AM

Have you made your calculations for all up weight with those specs?

Greg L.

Dec 22, 2005, 02:29 AM

Not yet, Tom. I figure it ought to weigh somewhere in the range of 7 to 10 ounces with the motor and folding prop. Right now I'm building a Herr Parkflyer Cub as a gift to my Dad. After I get done with that, I'll start in on the T-50X.

Greg

Greg L.

Jan 02, 2006, 01:13 AM

What do you guys think of covering it with Heavy Duty Silk? It may tear easier than the plastic coverings, but it will give CoastalFlyer a bit heavier glider for slope flying. Also, it will be more in keeping with the age of the design. :cool:
Let me know what you think.

Greg L.

BMatthews

Jan 02, 2006, 01:21 AM

The silk you get at fabric stores? DON'T DO IT! ! ! ! That stuff is far too thick and heavy and totally lacks the classic transparent look that this model just HAS to have. The overlap seams will be coarse enough to look like street curbs.

The old model silk is about the same thickness as 1/2 oz glass cloth or perhaps a little thinner. It looks fantastic but suffers eventually from the sun. But for the 5 or 6 years you'll get out of it there's nothing at all like it. Eventually it fades a little but more importantly the fibers rot from the UV and one day you go to pick it up just like all the other times and the covering pops and tears. For a while you can patch it but after a few more months it's hard to hold the model without poking a finger through it.

I popped back into this thread hoping to see some more pictures. You slackers get to work and get some inspiring pics posted up! Perspiring minds need to SEE this stuff... :D

mmartin55

Jan 02, 2006, 01:53 AM

How's about this Bruce..... the Thermic 72 parts are near done and the jigs made for cutting the tapered hardwood booms right to the plans....

No slackers here.

Greg L.

Jan 02, 2006, 02:57 AM

Hey, Bruce;
Actually the stuff I was refering to is/was made by SIG for covering model airplanes and is/was made in japan.

Greg L.

BMatthews

Jan 02, 2006, 02:29 PM

Hey, Bruce;
Actually the stuff I was refering to is/was made by SIG for covering model airplanes and is/was made in japan.

Greg L.

Ah, that's fine. When I saw the "heavy duty silk" I was reminded of some well intentioned guy that got the stuff from the fabric store and used it on a big free flight OT job. It was thick and as mentioned the seams looked like road curbs... :D It actually came out about the same as the iron on facbric coverings we use these days. But the real stuff is far thinner.

I didn't realize that Sig was still getting and selling the stuff.

Greg L.

Jan 02, 2006, 03:25 PM

Ah, that's fine. When I saw the "heavy duty silk" I was reminded of some well intentioned guy that got the stuff from the fabric store and used it on a big free flight OT job. It was thick and as mentioned the seams looked like road curbs... :D It actually came out about the same as the iron on facbric coverings we use these days. But the real stuff is far thinner.

I didn't realize that Sig was still getting and selling the stuff.

I was checking the sigmfg.com web site earlier and they still list it in 2 different wieghts.

Greg L.

mmartin55

Jan 02, 2006, 04:47 PM

Let me know how it goes Greg. I get all of our supplies and hardware from Sig and can stock it for inclusion with these kits if you guys like the performance of the product.

Tom

Greg L.

Jan 02, 2006, 07:43 PM

Let me know how it goes Greg. I get all of our supplies and hardware from Sig and can stock it for inclusion with these kits if you guys like the performance of the product.

Will do, Tom.

Greg L.

Greg L.

Jan 08, 2006, 11:26 PM

Irsudog, any updates on your build and flying? How's the new camera working out?

Greg L.

lrsudog

Jan 08, 2006, 11:44 PM

Got a new cam for Christmas, but absolutely no time to use it. Stupid relatives, always wanting to celebrate.

Greg L.

Jan 09, 2006, 11:39 PM

Got a new cam for Christmas, but absolutely no time to use it. Stupid relatives, always wanting to celebrate.

Glad to hear the Wife replaced your camera. Sorry to hear about the relatives, though. :eek: :D

Greg L.

BMatthews

Jan 09, 2006, 11:50 PM

Let me know how it goes Greg. I get all of our supplies and hardware from Sig and can stock it for inclusion with these kits if you guys like the performance of the product.

Tom

From a free flight perspective I can say that at 50 inch span tissue, either Jap or Silkspan, is far more often used for this size of model.

I know there's issues with punctures on the fuselage or lower wing surface but that can be handled by either switching to one of the parkflyer plastics or double tissue covering. Or even using a little known technique of putting tissue over thin mylar. (little enough known that I'd have to go and look it up)

Not to mention that if a guy has never used real silk before that it can be a pain to learn how and get a nice job on the first try.

So I'd have to suggest that if you put anything in the kit that it should be tissue paper. But what color? Nope, just let 'em get their own stuff.....

Greg L.

Jan 10, 2006, 12:58 PM

From a free flight perspective I can say that at 50 inch span tissue, either Jap or Silkspan, is far more often used for this size of model.

I know there's issues with punctures on the fuselage or lower wing surface but that can be handled by either switching to one of the parkflyer plastics or double tissue covering. Or even using a little known technique of putting tissue over thin mylar. (little enough known that I'd have to go and look it up)

Not to mention that if a guy has never used real silk before that it can be a pain to learn how and get a nice job on the first try.

So I'd have to suggest that if you put anything in the kit that it should be tissue paper. But what color? Nope, just let 'em get their own stuff.....

Thanks for the info, Bruce. One guy I know that has used silk has said that it is easy to puncure.
It sounds like the more I learn, the more I want to use light weight plastic coverings like Coverite Microlite. On the other hand, Coverite CoverLite Iron-on Tissue covering might be another good way to go. And at $4.49 a 19 1/2X36 roll it won't break the bank. Of course you'll need Balsarite to apply it.
You know, on second thought, I think I'll use the CoverLite instead. :D

Greg L.

mmartin55

Mar 27, 2006, 01:24 PM

Irsudog
Any updates on the 50X? How are the rest of you guys doing on yours. Any build progress or notes to compare?

Tom

Greg L.

Mar 28, 2006, 12:41 AM

Hi Tom;
No updates on my part, too many other projects going on. :( I have sheeted wing ribs one and two with 1/32 sheet top and bottom. Haven't covered the wings yet.

Greg L.

mmartin55

Mar 30, 2006, 10:34 AM

Hey I need to get some of these kits out of here.

Anybody want to help? I've got about 6 of both the old 50-X and the Thermic 50 on the shelf crying to be built.

No Step

Apr 14, 2006, 09:44 AM

I'll be starting my 50x any day now,.... as soon as it arrives. It looks like a fun little glider.

I'm also drooling over the box fuselage Thermic 50 w/ power pod. I had one as a kid probably 45 years ago,... rudder only with a rubber band powered escapment. Now it can be a Lipo powered electric, using micro gear, proportional R/E/T, and covered with mylar. R/C certainly has come a long way.