Guillow's Profile Basic Trainer 2 Wing

[scott baird]

I was given a Guillow's Basic Trainer 2 kit#820 from a co worker that built one with his father years ago who had purchased a second kit to use the wing to repair their first plane.The kit I received is complete except for the wing but they did trace original as well as include a 3" section of old wing for a cross section of the airfoil. I am wondering what balsa would be best. I scratch build rubber free flight/gliders so have an understanding on how to shape the plank but would like input on grain type and density as this is quite different than a small hand launch glider. Any help would be appreciated.Thanks

[scott baird]

When one of the clubs 6 of this model broke a wing, I replaced it with a shaped airfoil from SIG. Saves planning and sanding.  But I used to do HLG and making a solid wing isn't all that difficult, just time consuming and of course a very sharp l blade in your wood plane.

Hey Ty thanks for the reply. I had forgotten about sig but will check it out. You are correct on the sanding and planing. For smaller projects I tack plank to glass and start removing balsa checking with a template as I go. Makes one heck of a mess but kinda fun if you don't screw it up.

[paw080]

I was given a Guillow's Basic Trainer 2 kit#820 from a co worker that built one with his father years ago who had purchased a second kit to use the wing to repair their first plane.The kit I received is complete except for the wing but they did trace original as well as include a 3" section of old wing for a cross section of the airfoil. I am wondering what balsa would be best. I scratch build rubber free flight/gliders so have an understanding on how to shape the plank but would like input on grain type and density as this is quite different than a small hand launch glider. Any help would be appreciated.Thanks

Hi Scott, use 8-10 lb. quarter grain balsa. Do not use "C" grain nor "A" or "B" grain balsa.

Quarter grain balsa will be very warp resistant.  You do not need lighter wood for a trainer

design.  Tony G

[scott baird]

Hi Scott, use 8-10 lb. quarter grain balsa. Do not use "C" grain nor "A" or "B" grain balsa.

Quarter grain balsa will be very warp resistant.  You do not need lighter wood for a trainer

design.  Tony G

Thanks Tony.8-10 lb check. Quarter grain check. Looks like ill be calling National Balsa as Sig seems to be out of most wood. Now I know what would be best.

[bill bischoff]

 I have always thought that "C" grain and quarter grain were the same thing. Would someone please explain?

[Dan McEntee]

I have always thought that "C" grain and quarter grain were the same thing. Would someone please explain?

   That is what I had always thought also. maybe just a case of fingers exceeding the speed of his thought process? I learned that from several books and the section on balsa that was always in the SIG catalog.
   Type at you later,
  Dan McEntee

[scott baird]

I have always thought that "C" grain and quarter grain were the same thing. Would someone please explain?

Bill, I always thought the same with quarter grain being used to describe the thicker planks and c grain term used for thinner sheets. I am probably wrong and wait for someone who knows to chime in. I also am going to call a few balsa suppliers next week so I will let you know what they say. I have the ability to over complicate very easy tasks but want to get this wing right. I know it's a trainer type but still don't want to end up with Pringles chip for the wing.

[Dave Hull]

I think the grain orientation types A, B, and C were coined by Zaic of Jasco. Quarter grain is a much older description that sawyers have used forever. In Zaic's system, C-grain is quarter grain.

For a trainer wing, I would not be afraid of using B-grain at all. If the wing is at least 1/4" thick and of 8+ lb density I might use a piece of flatsawn material (A-grain) as well. C-grain tends to be brittle and shatter, and trainers hit the ground.

Divot McSlow


Ref.:  Model Glider Design, Frank Zaic, 1944. Page 161

[Dan McEntee]

  If it's 3/16" or thicker, I wouldn't worry too much about what type of grain, as long as it does have some grain too it. Anything over 6 pound density will be stiff enough for a trainer wing of that size, I'm thinking. Definitely don't waste good HLG swing stock on a trainer wing!!!
   Type at you later,
,   Dan McEntee

[scott baird]

Dave- Thanks. I have most of Zaic's yearbooks and always found them full of great info. I always feel compelled to build the older free flight designs even though I know a newer airplane (say 1950's 60's) would be more competitive. I guess I am crazy but I like to fly my peck one night 28 in p-30 as I have fond memories of that plane from my youth. Maybe one day I'll build a balsa tube rocket ship.

Dan- It measures 7/16 at thickest part of airfoil with glue on fixed flap pieces on trailing edge so I tend to agree. I don't have any c-grain remotely close to that thickness so glider stock is safe. It can be hard to find a great sheet of wood for hand launch and cat gliders if you get too picky.

[James Holford]

My dad still has his Trainer III!!!

 I lucked out n found the drawings for the Trainer II on ebay couple weeks back. Its on my scratch build list

Sent from my SM-G965U using Tapatalk

[scott baird]

My dad still has his Trainer III!!!

 I lucked out n found the drawings for the Trainer II on ebay couple weeks back. Its on my scratch build list

Sent from my SM-G965U using Tapatalk

James that's awesome. I assume you flew with your dad? I was on my own when I was growing up as my father did not build and fly models. He was encouraging and behind me learning but had no interest to do on his own. In looking at the kit I have I am glad I only have to replace the wing so not much of a scratch build for me just duplicating one part. The rest of the parts look pretty basic and easy to replicate except for the block that mounts to fuse in front of wing and ties into the engine mount up front. That piece seems like it would be tedious for me.

[paw080]

Dave- Thanks. I have most of Zaic's yearbooks and always found them full of great info. I always feel compelled to build the older free flight designs even though I know a newer airplane (say 1950's 60's) would be more competitive. I guess I am crazy but I like to fly my peck one night 28 in p-30 as I have fond memories of that plane from my youth. Maybe one day I'll build a balsa tube rocket ship.

Dan- It measures 7/16 at thickest part of airfoil with glue on fixed flap pieces on trailing edge so I tend to agree. I don't have any c-grain remotely close to that thickness so glider stock is safe. It can be hard to find a great sheet of wood for hand launch and cat gliders if you get too picky.

Hi Scott, there is a difference between the two types of grain. Quarter grain is quarter sawn and the appearance of the rays

is much tighter than what is seen with "C" grain.  Yes, we do use "C" grain for IHLG and OHLG wings; the visual appearance

shows much larger rays.   Take caution when selecting wood for your gliders. If possible take a scrap of the "C" grain balsa

and snap it. If the balsa breaks without splintering and looking like the it was cut with a razor blade, the wood is useless.

Eons ago, I flew High Ceiling IHLG at Tustin CA.  and I first used Glidette 16's (Hines design)  and then I designed my

own glider based on Curt Stevens and Lee Hines ideas. The fuselages were medium weight(6-8 lb.?) 1/8" sheet quarter

grain balsa. The wings and empennage were "C" grain balsa.  The best times(unofficial) were in the low 1:20's .

My point is that if the fuselages of these gliders were fabricated of "C" grain balsa; they would have been blown to

pieces during the launch.  I wish I could post photos of the appearance of each type of grain.... I also wish I could

throw a glider again(time marches on..)

Again, best of luck with your trainer.   Tony G   

[scott baird]

Tony G, thanks for the explanation. I have never tried the snap test always relying on weight, feel,appearance,and looking at sheet with a back light. Will try when I have to/want to build my next glider.

[Steve Dwyer]

Scott,

When I was 13 years in the early 60s I built my first Guillows Basic Trainer II. Returning to CL flying after a 60 year break I built a Basic Trainer III and named it after my grandson Evan. It took a little digging to find the plans, I made the wing using laminations of 1/4" balsa epoxied. It came out much heavier than I expected no doubt because of the laminated wing and I used a K&B green head 35 on it. My original II had a Fox 15 and got me into the air. My grandson did ok but he's not going to be the pilot I'd hoped for.

Steve

[scott baird]

Steve thanks for the story and pictures. It looks great. I had thought of doing a lamination but think I will carve out of a 1/2" x 6" plank. Your wing ought to be warp proof (if such a thing exists) and strong.

[Dan McEntee]

Hi Scott, there is a difference between the two types of grain. Quarter grain is quarter sawn and the appearance of the rays

is much tighter than what is seen with "C" grain.  Yes, we do use "C" grain for IHLG and OHLG wings; the visual appearance

shows much larger rays.   Take caution when selecting wood for your gliders. If possible take a scrap of the "C" grain balsa

and snap it. If the balsa breaks without splintering and looking like the it was cut with a razor blade, the wood is useless.

Eons ago, I flew High Ceiling IHLG at Tustin CA.  and I first used Glidette 16's (Hines design)  and then I designed my

own glider based on Curt Stevens and Lee Hines ideas. The fuselages were medium weight(6-8 lb.?) 1/8" sheet quarter

grain balsa. The wings and empennage were "C" grain balsa.  The best times(unofficial) were in the low 1:20's .

My point is that if the fuselages of these gliders were fabricated of "C" grain balsa; they would have been blown to

pieces during the launch.  I wish I could post photos of the appearance of each type of grain.... I also wish I could

throw a glider again(time marches on..)

Again, best of luck with your trainer.   Tony G 

   What you are describing here is what I have learned are called "wind checks" or something similar. I had read that in several sources through the years, going back to the book by R.H Warring that I often checked out of the library as a kid. And you would never use C grain for a fuselage anyway. Most plans call for grainy A or B grain for fuselages, and at least 10 to 12 pound stock to take the whipping motion from launching and impact with the ground on a bad launch. Not trying to pick an argument, and I may be a little foggy on some information. I think most of this is covered in Dave Thornburg's "Old Buzzard Soaring Book" which was made up of a series of articles from Model Builder magazine, and included his trials and tribulations learning to build and fly hand launch gliders f or competition. It's a GRAT read if you have never read it and can lay your hands on a copy.
  And I wish I could still throw a glider also! Thank God for Catapult gliders!
     Type at you later,
    Dan McEntee

[paw080]

Hi Dan, I learned IHLG and OHLG from Lee Hines and Ron Whitman, Lee was my modeling,

 Snooker playing and girl Chasing buddy. My mother considered him an adopted son.

I learned indoor stick and microfilm construction technique from Ron.  I enjoyed insane indoor

glider contests at Wilmington Hall and the Los Angeles armory. All this was between

1958 and 1962 when both Ron W. and I enlisted in the USAF.  I learned everything

about balsa wood and properties from Lee. Lee learned everything about Enchiladas

 and Tamales from my mother. I blew my throwing arm out playing volleyball.

Tony G

[Dave Hull]

Tony,

I think you are creating a distinction where none truly exists. This may be an "indoor glider guy" thing that evolved over the years? I still can't make sense out the statement that quarter grain has rays with "much tighter appearance than what is seen with C grain." That implies smaller flecks. So in a glider guy vernacular, is the quarter grain more of a radial cut or is the C-grain?  (In my opinion, a true radial cut will have the largest fleck size, for a given section of a log. This would be the opposite of how I interpret your comments.)

The original grading system was given and explained in both words and a diagram of how a log can be cut to yield A, B, and C grain.

Here are a few more tidbits from the source:

"If a plank is cut right across the log, such a plank will be exceptionally rigid and it will tend to crack  before it will bend. In lumber circles such a cut is known as a quarter-cut (because if a log is split into four quarters the grain will be as shown)....  In the model world, JASCO has tried to simplify the various grades of cuts by referring to them as "A,"  "B" and "C" cuts or grains."

The diagram showing the end of a log shows the "C" grain label is entirely consistent with the traditional sawyers quarter grain cut.

Any size aspect of the medullary rays is the likely result of the growth pattern of the individual tree. A slower growing tree will be more dense, with more closely spaced and more prominent growth rings, and hence a tighter speckle pattern. Think Guillows die-cut sheets here. However, as the planks or sheets are more and more offset from the true quartered edge, they will angle thru the plank, making them appear shorter. It is a judgment call when it isn't sufficiently radial cut so that it becomes, in Zaic's grading system, a B-grain cut.

Probably the most notable use of quarter grain terminology, other than with model builders, is in the construction of Arts & Crafts style furniture (Also Mission style and Stickley style) out of oak. They insist on using true quarter grain for the flecked appearance, else, it just doesn't meet the standard of that style.

In the home construction industry, they mill some high-end Doug fir with what they call "vertical grain." It is simply quarter sawn wood, but fir has no rays in it.

For a slab trainer wing for a control line plane, getting a good density would get you where you want to go. I'll leave it to glider experts to argue how many degrees from quarter sawn is still quarter sawn, or if "C-grain" is allowed a looser tolerance.


Divot McSlow

[paw080]

Hello Divot, perhaps you're right, I was making a distinction between large flecked and

tighter flecked balsa. If they result from the same angular cut, then the difference is the

result of growth environment.  I'm far removed from where glider technology  has evolved.

I did use what I learned from my modeling peers of the late1950's to the middle 1960's;

when I embarked on FF power/A1,A2 and control line model construction.  Them's the

old days, now I just build and occasionally fly control line sport models.   Tony G

[Steve Dwyer]

Scott and Jim,

Drifting away from the "balsa" side of this thread, I found both your comments interesting especially about your father and your friend's father that was involved with the Guillows Trainers II & III. I can still recall the smell when opening that particular kit and that is after opening many kits since then.  It's funny how a particular odor remains etched forever in your memory. As a youngster my dad worked two jobs and was rarely around to support me with modeling yet he would always encourage me. There was a man down the street in his mid thirties that was an avid model builder who many of the kids gravitated to. He was the guy who took me to a flying field to fly my Basic Trainer II. He and his friend helped me start it and he held on to the J Walker U Reely he used to get me thru my first flight. He later coaxed me into building a Super Clown I have restored and still fly. Attached is a photo of Bob now 94 when I visited him recently in a nursing home. Brings back fond memories!

Steve

[paw080]

Scott and Jim,

Drifting away from the "balsa" side of this thread, I found both your comments interesting especially about your father and your friend's father that was involved with the Guillows Trainers II & III. I can still recall the smell when opening that particular kit and that is after opening many kits since then.  It's funny how a particular odor remains etched forever in your memory. As a youngster my dad worked two jobs and was rarely around to support me with modeling yet he would always encourage me. There was a man down the street in his mid thirties that was an avid model builder who many of the kids gravitated to. He was the guy who took me to a flying field to fly my Basic Trainer II. He and his friend helped me start it and he held on to the J Walker U Reely he used to get me thru my first flight. He later coaxed me into building a Super Clown I have restored and still fly. Attached is a photo of Bob now 94 when I visited him recently in a nursing home. Brings back fond memories!

Steve

Hi Steve, Scott and Jim, I'll also drift away from the Balsa topic and say that my father decided to get in on the

control line action after putting up with my modeling Shenanigans for over 15 years.  Sometime in 1957(??);

my Dad bought a Guillows profile Basic Trainer and an OS Max-1 35. He built it and soloed his first flight. The

Max-1 was a bit of overkill for power but the model was a very good primary trainer. This Guillow's Basic Trainer

must have been the prototype for the later introduced Basic Trainer  # 1,2,3 series.  It was about the same size

as the # 2 model, I think it had a 32" span. Here is a link to a pic of the Guillow's Ad for the Reactor, Trixy and

the Basic Trainer.    http://builtrightflyright.com/2019/kits/Glo/trixy01_2017.htm

Tony G

[scott baird]

Thanks to all for your help with me trying to figure out what I need for the wing. All good information and appreciated. Steve and Tony thanks for sharing your personal experience with the Guillows trainers. I look back on my own path with model airplanes and have a soft spot for many kits that helped to get me started.