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-   -   Building and flying the LST 1/2A Trainer (http://www.rcuniverse.com/forum/1-2-1-8-airplanes-70/2301186-building-flying-lst-1-2a-trainer.html)

Bipe Flyer 10-30-2004 03:06 AM

Building and flying the LST 1/2A Trainer
1 Attachment(s)
I started drawing up a trainer with a 40" span that should be suitable for .049 to .074 engines.

It should be pretty obvious what it is patterned after. If anyone is interested in building one I'll post the plans when I'm finished.

EDIT UPDATE 12-09- Plans and templates available as per this quote;


ORIGINAL: Bipe Flyer

The 1/2A All the Way MSN site is gone, so here are new links to the plans.


BMatthews 10-30-2004 04:25 AM

RE: 1/2A trainer anyone?
Well, it's got a high wing so it must be a Piper Cub.

Do I win anything?


rrragmanliam 10-30-2004 06:40 AM

RE: 1/2A trainer anyone?
SIG Kadet?
Looks good Bipe. Should be a simple straight forward build. I wish more people new to the hobby would start with a kit or a simple scratch build. I mean really with good instructions and a little help most people could build the thing right. That's how most of us started. It's a great feeling to step back and look at individual structures and a completed plane that you built from a pile of parts and glue. Flying is great but building is what hooked me on this hobby. I don't get alot of satisfaction out of an ARF. Cost and transportability also make 1/2A a great choice for a first plane.


mclintock 10-30-2004 09:12 AM

RE: 1/2A trainer anyone?
The little Kadetlet looks good- I also like the shape of the tail on the kadet mk11, but that may be harder to make..
One thing that might be a boon to beginners trying this (or any) 'electronic' plan- where you download and print yourself- is a 'printwood sheet' layout. An image of a rectangle representing a 3x18 or whatever common-sized balsa sheet with the outlines of all the ribs, etc that are to be cut from that sheet might be helpful for a novice- and would ensure the grain is going the designer-intended way for all the parts.

I know a lot of people now make a hard rib template for constant chord wings, then do all the ribs from that- but I still do it the hard way, by making 'printwood' using a xerox copy with lacquer thinner rubbed on the back to transfer onto the balsa.

I like it,

flyinrog 10-30-2004 09:57 AM

RE: 1/2A trainer anyone?
Looks like a Whizard to me, nice job,,I agree it needs a wing rib template...what are those funny looking round things hanging off the bottom?:)...Rog

Bipe Flyer 10-30-2004 10:43 AM

RE: 1/2A trainer anyone?
1 Attachment(s)
Yes it's a mini Kadet.

I drew an optional fin and the rib layout. I'm just going off of pictures, so I may not have the fin exact. I still have to draw the spar and LE cutouts on the ribs etc. I was going to go with a Clark Y airfoil, but I decided to use an airfoil that could be built flat on the workbench.

ZAGNUT 10-30-2004 11:04 AM

RE: 1/2A trainer anyone?
looks nice but would be an easier build for beginners if the firewall and formers were all the same width from trailing edge forward. make them the same as the trailing edge former and you also reduce some of the "chunkiness" up front.


Bipe Flyer 10-30-2004 11:35 AM

RE: 1/2A trainer anyone?
1 Attachment(s)
Then an .074 wouldn't fit. I used a Kadet Senior as an outline for the fuse.

Here's what a simplified fuselage would look like.

BMatthews 10-30-2004 02:01 PM

RE: 1/2A trainer anyone?
I agree that simple is better. Getting serious (what? Not a Piper? :D) I would suggest loosing the landing gear for beginners. They typically fly off a grass field and we all know that if the grass is not putting green smooth or the wheels are not HUGE that a 1/2A model will typically nose over. I'd also suggest that for a trainer you would be better to loose the ailerons and go rudder only with throttle as an option depending on the engine. Here again it's simpler to build that way.

I do like the 40 inch span as it provides a bit more area and drag. Speaking of drag for a trainer a fat semi symetrical airfoil similar to the one on the Littlest Stik may be a good idea as it's thick enough to offer some speed controlling drag while not being so highly cambered that it would encourage a lot of speed related ballooning out of turns and dives. If you use that airfoil the lower rear surface is flat for easy building and if you use a piece of 1/4 sq set on a diagonal it would fit right into the mouths of the ribs without requiring the table surface for support.

mclintock 10-30-2004 02:45 PM

RE: 1/2A trainer anyone?
Man, isn't cad awesome! Now make it a canard pusher bipe with elliptical wings and we'll be in biddness.. [&:]

Seriously- I may have to build it now since you drew up the rib sheet pattern..

Oh while I have my arm chair quarterback helmut on, I have a wish for the wing-
like Bmat said, having the leading edge in as a square stick turned on diagonal (herr style) is great- I think the way my kadet junior wing was made was awesome- the top was sheeted from leading edge to the middle of the main spar, then cap strips went from the middle of the spar on back to the trailing edge. It was hugely strong and what i liked is that there weren't the rib hills and valleys along the top front of the wing, since it was sheeted. Isn't that called 'D' wing construction or something?

Bipe Flyer 10-30-2004 05:13 PM

RE: 1/2A trainer anyone?
Wheels and ailerons could be options. I've flown smaller planes off of grass with no problems. Personally I think that a person is better off learning on 4 channels, including taxiing. Rudder/elevator only is easier to build, but not the easiest to learn with. Beginners often get heavy on the elevator and find themselves at high AOA with little airspeed where ailerons are much more forgiving than the rudder. I think that one of the best characteristics about how the Kadet series of planes flies, is that they don't need a lot of elevator in turns. I've used this airfoil before, albeit on a low wing, and it has performed very well. I'd rather people leave off a few things if they simplify rather then not know how to add ailerons or gear if they wanted it. I do prefer the angled LE though as it is stronger and needs less sanding.

McClintock, yes it is D tube construction and is very strong, although it does take a little more difficult to build. I'm trying to keep the wing construction simple, that is why there is little sheeting and no cap strips. There's nothing to stop someone from building the wing that way though. For myself I would use sheeted foam (no it isn't heavier when done correctly), but I know most people don't have a foam cutter or prefer built up wings.

Farmbuyer 10-30-2004 09:29 PM

RE: 1/2A trainer anyone?
I for one would be interested. I have a Kadet LT-40 and really like it. A 1/2A version is just what I need to fly outside my front door (hence my effort with the converted electric one I have been seeking advice on and hoping to maiden it tomorow!). I think I get a bigger thrill out of my small planes.


Bipe Flyer 10-30-2004 10:30 PM

RE: 1/2A trainer anyone?
1 Attachment(s)
Here's how I could go with the ribs using some of BMatthews' and McClintock's suggestions.

1/4" leading edge on diagonal with fully sheeted ribs where the rubber bands are and D tubed ribs for the rest. I've drawn the ribs alone as well as with the spars, LE, TE and sheeting.

DustOffUH1 10-31-2004 12:49 AM

RE: 1/2A trainer anyone?
When you get the plans finished. I'm game :D I'm building the 1/2 A Herr J3 Cub, 48" wingspan, with a Norvell .061, almost done. Also installed Curtek lights. Its been a pleasure to build. I'll post some pics when I get the cowl painted. That's about the last thing I need to do. I'm still a beginner, and it really wasn't difficult. I also have the Herr "Breezy Day Park Flyer Kit, 35.25" wingspan. Haven't started that yet. I agree with Darren. Building for me is at the very least half the fun/pleasure. I could build & cover planes all day long. I do have TurboCad ver 8. Got it off ebay for about $10. Haven't seriously started playing with it though. I do plan on building some stuff from the free plans from Fly RC and MAN also. Anyway, enough of my babbling for tonight. Hey I just noticed, its past midnight. Its now officially my BDay :D I'm a 43 year old kid ;) I get an extra hour today as my Bday present too.

Remby 10-31-2004 03:00 PM

RE: 1/2A trainer anyone?
Lookin good!
I would suggest adding some doublers in the front, and adding some extra beef to the wing. A trainer is best built using crash-proof structure, otherwise it quickly becomes a fly n fix bird. This adds some weight, but adds to it's survival during the learning process.
I usally add a 3/32 dowl across the front of the L.E., makes it MUCH able to survive even small tree impacts, and is easy to cover with as the round accepts the covering without added sanding. Very little weight is added, but it will add many more flights.
Don't mean to rebuild this for you as it looks great, just considering who the trainer would be used by and all.


gcb 10-31-2004 04:30 PM

RE: 1/2A trainer anyone?

I like your decision to use built-up stick formers. That is a lot easier for a beginner than to guess where the holes go when installing the radio.

Noticed that you don't show sheeting between the spars. Did you decide to use a "C" tube instead of a "D"tube? Both work well.

Keep up the good work. I am considering building it although I am currently interested in control line.


Bipe Flyer 10-31-2004 05:40 PM

RE: 1/2A trainer anyone?
Thanks for all the suggestions so far. It's no easy task to design light, strong and still have it be what every person considers to be good trainer. I like the feedback though as it means that it is a worthwhile project.

I'm not a big fan of crash proofing, but a dowel leading edge could be another option. Again, this is where I would prefer a foam core wing because it has a very good strength to weight ratio and is easily repairable. I will probably add doublers under the wing or possibly between the firewall and first former, although I rarely use doublers when building for myself.

I really like stick formers. I think that they give the most strength for the least amount of weight. I don't like using ply unless I have to. You're right, I haven't drawn any shear webs yet. They should go between the spars, but I will probably draw them on the back of the spars as this makes building easier.

jboy381-RCU 10-31-2004 07:45 PM

RE: 1/2A trainer anyone?
i wish i had a little of the talent in this fourm...bipe, are you planning to put the plan on 1/2A all the way site???i would love to add it to my building list...i'm not going to add anything to improve the design, because the oringal is a great design in itself...


mclintock 10-31-2004 07:54 PM

RE: 1/2A trainer anyone?
It just keeps getting better..
another cool thing since the plans are electronic might be a 'scale factor' or something where one could scale the plane to match the popular engines sizes-- but that may take experimentation.. I wonder if a tee dee .020 and a babe bee would haul the same size frame, or more equally than say a pee wee and a tee dee .020.

I guess that's more of a general concept than one to apply to just this trainer model.. There's probably an area rule I should know for scaling. Thinking of the LS150 example, I guess to make this kadetlet a .02 you'd just devide by 150 percent instead?

This whole thread is helpful for us fledgling scratch-building wannabes like me to see how to draw and implement concepts of a familiar design- you make it look easy Bipe! (not that I think it's easy-)
thanks for sharing,

Bipe Flyer 11-01-2004 12:10 AM

RE: 1/2A trainer anyone?
I'll post the plans here and on the 1/2A all the way site when they're done.

I'd say somewhere around 22" for an .010 and 30" for an .020 should be good. As far as the reedies vs TeeDees goes, there is always a range of acceptable engines for any given design. I'd say that at the 40" span a Babe Bee would be the bottom end and a Norvel .071 would be the top.

Once the design itself is done, I already have a solution for scaling. ;) However, that isn't my reason for drawing up this plan. I just thought it would be good to have a freely available plan for first time 1/2A flyers.

ptulmer 11-01-2004 08:56 AM

RE: 1/2A trainer anyone?
Beautiful job! I think I know why you Canadians are starting to post again... It must be cold there! It won't get cold here till late January.(Then it warms up in mid-Feb :D)
Well, I guess I can put my plans for a 1/2a trainer aside now.;) Really, you've done a first class job there.

Remby 11-01-2004 11:42 AM

RE: 1/2A trainer anyone?
A good idea getting beter. The doublers you mentioned are just right. The dowl idea works for those who fly at less than ideal flying sites.. It can make a wing go from minor repairs to no repairs needed in the event of a pilot error. Super project!

Bipe Flyer 11-01-2004 05:04 PM

RE: 1/2A trainer anyone?
I was thinking about a name for this plane, and liked Clint's "Kadetlet", when it occurred to me that it would be nice to dedicate it to the memory of Lynn Sipes. Putting LS somwhere in the name seems appropriate. Any ideas?

mclintock 11-01-2004 05:24 PM

RE: 1/2A trainer anyone?
That's a good idea, plus I think Lynn would have liked your little .02 sized bipe you just made, maybe since it has a cute look like the LS 150..
Sipes of rhymes with bipe too.. for what that's worth. Sipes' Bipe?

Oh wait- Maybe the trainer could be the "LST"?

jboy381-RCU 11-01-2004 07:22 PM

RE: 1/2A trainer anyone?
i vote "LST" he would be all over this if he were hear...


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