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

David Ingham 10-28-2007 02:38 AM

RE: 1/2A trainer anyone?
 
Looks good, Avroarrow. What type of construction is it? What is its goal?
I have tried reinforcing my balsa Push-up with a bit of carbon fiber, but, as a casual add-on, it may not add much strength. I put an 049 size three blade propeller on it backwards to slow it down. The larger propeller should also make it quieter. It is nearly fixed from the last crash.
As in the real world, in modeling it is now the environment that counts more than the survival of the individual. Here near the Si Valley, anyway, a flying field where one can burn fuel is worth more than any individual airplane.

David Ingham 10-28-2007 11:57 PM

RE: 1/2A trainer anyone?
 
1 Attachment(s)
Here is Pushup fixed. The splined part of the crank that takes the drive washer is broken, so I put on my spare Peewee. First time I have broken A Cox reedie. I experimented by adding some carbon fiber, but I don't know if the way I did it will help much. I have an 049 size three blade propeller on backwards now. It was much too lively for a primary trainer. I have sheet brass (and silver) that I could make a muffler out of.

avroarrow 11-01-2007 04:37 AM

RE: 1/2A trainer anyone?
 
Hello David...I used "D" tube balsa construction in the wing, 1/16 & 3/32 balsa throughout the fuse,covered in solartes. finished weight 17.2oz. It s a mirror 1/2 sized image of the original kadet senior, in construction.39in wingspan.1/16in sheet on the wings with cap strips,tail and fuse I used 1/8 sq balsa ,sheeted in the forward section and forward fuse with 3/32 balsa,landing gear area has 1/8 ply .
Dave...it's goal was to replicate the larger sienor in flight caracteristics, slow easy to fly on 3 ch's...it does this very well, better than expected and flies at a craw when slowed up with a little up .I didn't want a flying dart which sometimes happens when you downsize. Now I'll build a set of skis and floats and see if it will do all the seniors jobs, just a little smaller that fits in your trunk, bring it anywhere, fly it anywhere.I built 2 of these when I started, one for myself and another for my father as he learned on the full size ...it fly's just as well.It's not that difficult a build, but time consuming cutting all the small balsa .
Don

David Ingham 11-03-2007 12:10 AM

RE: 1/2A trainer anyone?
 
Yes, I think it is harder to build on a smaller scale. I am fortunate to be short sighted. There are reading glasses, and there are magnifying glasses and min-binoculars, to attach to glasses, that jewelers and dentists use. Too bad 010s are so expensive now. I feel that 049 is good for CL, because one can't fly too slowly in anything but sill air or the lines will go slack.
For RC, 020 seems too big, so far as I have tried.

Small scale reduces angular momentum by the square of the size times the weight, so, unless they are much slower, smaller airplanes respond much faster to the controls. So, for instance, an unstable model is much harder to fly than an unstable piloted airplane, but rudder only or aileron only turns work a lot better if it is stable. I think generally, for a stable model, this is yet another advantage of small scale. {This is also why small sports cars are so fun to drive.}

When I first saw RC planes fly the electrics weighed around a pound! So it is traditional for RC planes to be big and use high nitromethane fuel, but neither is useful today.

rszanti 11-03-2007 04:02 PM

RE: 1/2A trainer anyone?
 
David -

Smaller planes do respond much quicker to the controls and so are much more sensitive to control inputs. Larger planes respond more slowly and are not (usually) as sensitive to inputs. This makes it easier for a beginner to learn on a larger plane. This is why so many nitro flyers will recommend a 40 size plane as the best size for a beginner to train on. And going with a high wing, such as your pushup, results in a more stable flyer than a low wing so the high wing also contibutes to being a better trainer. And of course a relatively slower flying plane gives you more time to make decisions.

By the way, .010s are expensive but so are .020s. The .049 is still cheap and sticking a few in the dirt (as I did when I was a beginner) is not as budget breaking as destroying the smaller engines is.

If I was starting out today on a limited budget, I'd go with a .049 - .09 engine size and a high winger.

Richard

David Ingham 11-05-2007 11:45 PM

RE: 1/2A trainer anyone?
 
Yes I chose a free flight design, high wing, high fuselage, and whatever, because I figure having flown a lot of rubber powered planes, I should be able to trim it, and set the travel of the control surfaces, so it is easy to fly. I have not succeeded in doing that yet.
The smaller the plane, the better the combination of slow flying and crash worthiness. I know this from basic principles, and it fits our experience.
If the plane is stable enough, I think the faster response is an advantage to a beginner. He can forget about controlling how long it takes it to go into and out of a turn and just steer it the way he wants to go. This is pretty much the way beginners fly 049 CL planes (in only one axis), and that is not why small CL planes are hard to fly. They are hard to fly because the lines have to be (air drag and wind) so short that there isn't enough time to react. Without lines, I don't see much advantage to large size, except in this case lower cost, and I see a lot of advantage to small size. I don't know yet what electric trainers are like.
At the ridiculous extreme, I read that a bacterium knows nothing of momentum. If he is going along full speed and stops swimming, he coasts to a stop in less than the diameter of an atom. So the few molecules that substitute for a brain don't have to do anything about timing. Only what direction and speed to go, and maybe which way to point.
I agree that an unstable or marginally stable small airplane, or with too much control available, is harder to fly than a larger one.
I have noticed that 020s are more expensive than 049s, and I have several 049s I could borrow from my old airplanes, but the cost is still less than my wife spends on her hobbies (even not counting making the apartment look nice, which is her main hobby). I don't need a TD 020 at this time, because my main engine problem has been too much power.

OzMo 11-06-2007 12:28 AM

RE: 1/2A trainer anyone?
 
Hey David,
Well don't give you will get er done! Just wanted to let you know the Cox 049 Sure Start motors are only 7 or 8 bucks each right now from cox. you could use one of those with a bag full of spares foe the kid's plane. 049 can haul planes as big as 2 meters such as a Gentle Lady glider and the go slow enough to be fun for the kids. puting a fuel motor on the nose is pretty common practice. If I recall the plans even sow this.

David Ingham 11-07-2007 01:58 AM

RE: 1/2A trainer anyone?
 
Yes, I know that Sure Starts are $6.99 from Cox Hobby Distributors. I like the tank mounts, but I got three for spare parts.
I fooled a little once with powering a big light free flight styrofoam glider with an 049, but the engine was too heavy and the glider was very fragile.
It seems that I am on a good track, but it will take more time to get back into the hobby, after so long away.
I put nylon engine mounting screws and a foam rubber spinner on it, now. I did some carbon fiber reinforcement, while re-building, but I don't know if this casual add-on will really help much. Waiting for time to fly again.

Yuu 11-07-2007 09:36 AM

RE: 1/2A trainer anyone?
 
There was an article in Model Aviation...or somewhere... where the builder took the $4.00 foam glider and made the rudder a full moving 'fin' for the slow speed rudder, and made the stab and elevator a 'full moving elevator" as well. He used wooden dowels and just glued a servo arm to it. With Lots of control, he didn't have much trouble with the foam, but he did wrap the fuse in clear packing tape, and the wings had packing tabe on the top and bottom.

avroarrow 11-13-2007 08:52 AM

RE: 1/2A trainer anyone?
 
:) Hi Dave, I was just thinking, maybe I'll build a plane for my cox 020 ...I't doesn't have a home and it's fresh with new glow head just sitting in a box....and spec's on your little plane like wingspan, fuse length. I can draw something up and cut balsa from there. I will add carbon fiber to the center spar as this will add tremendous strenght to a model of this size and add practically nothing to weight.I've used some 8mmx2mm carbonfiber ribbon on the spars of my 2 meter sailplane with very favorable results.You can get hollow carbon fiber tube that works well also.:D

avroarrow 11-13-2007 09:09 AM

RE: 1/2A trainer anyone?
 
oh yes i forgot, i built a couple of those foam gliders, using a cox o49 black widow on the nose,2 futaba 3003's for the rudder elevator and it flew okay but needed to be a lot lighter as by the time I got everything epoxied on, fiber taped the fuse and wings, it flew but was a hand full, ended up to heavy. I'd now like to try a few projects of these now that lighter equipment is much cheaper and my knowledge of building and flying has increased greatly. This was only my second plane I'd ever tried to build and fly in my earlier RC days, trying to build a cheap plane,re-using what I already had.It worked but not well.Actually I still have the plane stuck in the rafters of my shop as a momento of when I first entered this hobby back in 1990. I've looked in hobbyshops and Walmart for these cheap foam gliders, but they have kind of disappeared from the shelves around here.
Don

David Ingham 11-30-2007 10:13 PM

RE: 1/2A trainer anyone?
 
I added a little carbon fiber to my Push Up when I re-built it after diving onto the street, but I have little experience in using it. It worked fine fixing my prescription glass diving mask.
The other thing I did was to start making spinners of cork or silicone glue, when I don't have Cox rubber spinners that fit. One of these might have saved the crank shaft and greatly reduced the damage to the model. A rubber spinner was also useful when I forgot to step back after holding the tail of a C/L plane and it hit me in the knee.

avroarrow 12-02-2007 05:15 AM

RE: 1/2A trainer anyone?
 
Hello Ozmo, ...yes the Gentle lady plans did show a cox 049 on the nose as I built my first one that way, but soon built a pod to attach to the wing because I bought every plastic 6x3,6x4 prop with in a hundred miles , needed a new prop almost every landing when the motor was on the front of the glider.I have built 3 lady's, all were powered with an 049, but I converted my last build to an electric, tower Pro combo, graupner 9x7 folding prop and 3 cell lipo. It works very well, with long flight times, averaging 30/45 min as when you loose altitude, just hit the throttle and back up we go, something the cox could never do in the air, restart!....but I did get some great long flights when "d get into heavy thermals and the set up doesn't break the bank account.

Yuu 12-03-2007 03:35 PM

RE: 1/2A trainer anyone?
 
Avro... Saving props on the nose of a 'Gentle Lady' is easy.... look at the prop, and pretend the prop is being blown in the wind ....when the engine stops ....on the 'next' compression stroke. This 'position' is where you set the prop before you tighten it. Then, when the engine dies, the prop rotates to the "counter-clockwize" position in the wind.... to the "horizontal" position... and you land with a good prop. [ I learn't this from 'somebody' ....not Raymond...]

David Ingham 12-16-2007 11:16 PM

RE: 1/2A trainer anyone?
 
I lost another airplane! My Keith Laumer Pushup flew away again, and this time we didn't find it.
I took my grown son to the field that skaliwag showed me. I was starting and launching and he was flying. Though it was afternoon, the wind was very light and variable. After several tries, it flew. He was able to turn it up wind, I think, but not until it had blown quite a distance. I think the white speck got larger, until the engine quit. Then, because I had the rudder wrong, he was no longer able to keep it flying straight, and it went farther down wind. We looked until it started getting dark.
Anyway, the airplane was not as important as my getting back with my son.
So I need either to get a whole new set of radio equipment or to buy another RTF (whose equipment is likely to outlive it) or to replace the Rx and servos, with identical or compatible ones so I can use the same transmitter. I have more engines and wood.
I am still thinking in terms of a Pee Wee trainer and don't have any throttled 020s, so I don't need more than two (or three for expansion) channels, but even lighter weight would be nice. The Cox µ Warbird servos seemed to have plenty of force and speed, for this larger airplane.
The rudder horn broke on one crash. As I remember, it was the one from the µ Warbird, and therefore overstressed. There was some problem with the engine, probably due to stuff stuck in the intake. Otherwise, it took crashing into small bushes without complaint.

David Ingham 12-18-2007 01:44 AM

RE: 1/2A trainer anyone?
 
Another problem about building on such a small scale is that when I drop parts on the rug I often can't see them.

BMatthews 12-20-2007 03:04 AM

RE: 1/2A trainer anyone?
 
I hate to say this guys but this thread is supposed to be about Bipe Flyers' trainer and discussions about building and flying that one model only. All this recent stuff should have been in a new thread of it's own.

I'm going to have to delete all the posts that don't relate to the original design. Unfortunetly I can't split this recent part away into a new thread. I don't have the tools to do that at RCU. I'll leave it for a day or two so please finish up any last points or better yet re-ask any questions in a new thread. Then I'll run through this and purge all the stuff that's not pertinent to the original topic.

Or perhaps I can just cut and paste it all into a mondo quote and start a new thread with the mega quote. There's some good stuff in these posts and it would be a shame to loose it. But it's got to go from here in order to help keep the sticky on topic.

David Ingham 12-20-2007 11:57 PM

RE: 1/2A trainer anyone?
 
Sorry, the title and especially its being sticky lead me to think it was a general discussion of 1/2A RC trainers. Don't worry about saving my posts, I will know more later.

BMatthews 12-21-2007 01:07 AM

RE: 1/2A trainer anyone?
 
No problem David. I figured that it was something like that.

hogflyer 12-21-2007 05:11 PM

RE: 1/2A trainer anyone?
 
Bruce,

It may be helpful to rename this thread more specific to Bipe's trainer and start a general 1/2 Trainer thread (stickied at the top) for general questions. Just a thought.....

Hogflyer

avroarrow 12-22-2007 07:57 AM

RE: 1/2A trainer anyone?
 
Sorry to guys, I was under the same impression as Dave thinking this was a 1/2a general Thread.

David Ingham 01-21-2008 02:42 AM

RE: 1/2A trainer anyone?
 
Why is this thread sticky?

Mooney_driver 01-22-2008 04:22 PM

RE: 1/2A trainer anyone?
 
Please excuse the intrusion into this thread. I was directed here in a quest to find out how to make my own leading edge stock since there are not a lot of sizes offered these days.

I am looking for a trainer and a 1/2A trainer would be ideal due to size. I am trying to get back into actually flying and want something simple, cheap, small and easily repairable or rebuildable if it should become kindling.

I got a bit lost in the thread but early on it was suggested that a printwood template be included. I really like that idea and it would make it very simple for us newbies as I am not always sure which direction to cut since it would be more efficient use of the balsa slab if the rib was cut across the sheet but that is not the best way to cut for stuctural integrety! It also helps in trying to figure the cost that will be incurred when buying balsa. I tend to buy the 4" wide stock but 3" is very common even in craft and office supplies and with a printwood drawing it helps us with the bill of materials. It is also helpful if there is a bill of materials to use as a shopping list.

I see in a lot of the 1/2A threads that the tendency is toward 2 channel birds. I think this is a mistake. Planes can be made into 2 and 3 channel if the original calls for 4 channel but it is much harder (for us newbies) to take a 2 channel and add ailerons (although throttle is mostly a no brainer).

The idea of no landing gear also has merit but I think the plane should include landing gear on the plans and easily removable.

I am seeing several kits like the Herr Cloud Ranger that are taildraggers. This might be a good idea for a trainer but taildraggers for us new comers are frustrating and watching a lot of the "experienced old timers" fly tail draggers tells me that most of them never quite mastered it either! Yes they get them in the air but I am often not sure which direction they are eventually going to be going when leaving the runway! With that said, I think a trike gear is by far the best and least frustrating for the newcomer that is going to be flying this trainer anyway.

Thank you for letting me step into this thread. Bipe, I really like your trainer.

Mooney_Driver in the cold northwest

Bipe Flyer 01-27-2008 09:58 PM

RE: 1/2A trainer anyone?
 


ORIGINAL: David Ingham

Why is this thread sticky?
See http://www.rcuniverse.com/forum/fb.asp?m=2529572

BMatthews 01-28-2008 01:53 AM

RE: 1/2A trainer anyone?
 
OK, the title of the thread has been changed to more accurately reflect that this is about the LST trainer.


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