Stout Trainer - Mid to Advanced Trainer - Preview

by dharkless | November 8, 2015 | (7) Posted in Projects

Hello everyone,

The flying season is winding down here in Western Pennsylvania so I have returned to the building board.  I have a couple of designs I have been flying for a while but have not written up yet.  This is one of them.  I have flown this for more than a year but did not write an article on it because I was not able to provide adequate plans.  Unlike most of my previous designs you need full sized plans to build this one.

 

It looks like this:

(No power pod or servos yet)

This is a basic intermediate or advanced trainer depending on the wing option.  You can start with intermediate wing with dihedral and then move up to advanced by simply making a second wing with no dihedral.  It uses a standard FT power pod with tabs removed.

Although it is not patterned after any specific real airplane it does have a somewhat scale appearance.  It looks and acts pretty realistic in flight.

  

We call this the "Stout Trainer". The name came from a comment by Bob McBride who is doing the drawings with me for this design.  When I first sent pictures to him he responded saying, "That looks like a really stout wing on that trainer."  I liked the ring of it, "Stout Trainer".  We have been calling it that since.

“Necessity is the mother of invention”.  Truer words were never spoken as applies to the “stout” wing on this model.  I was helping the physics teacher at the local high school learn to fly with a buddy cord as a part of my involvement in his aviation based STEM class.  Well, there is not a loop that Mr. Rupert does not like.  I had flown this airplane numerous times including frequent tight loops.  “Rupe” as his students affectionately call him, proceeded to do the tightest possible loop with full power.  We had gone up with about 5 degrees of dihedral.  All of a sudden we were flying with about 20 degrees.  I immediately took the controls back and somehow nursed it back to a safe landing.  Obviously the wing had failed.  The glue joint was still tight but the wings top panels had developed wrinkles and some delamination on each side of the centerline.  That evening I decided to do a quick and ugly repair so I could get back out flying as soon as possible.  I cut it at the centerline and made 10” wide top and bottom splice panels to reinforce the weakened area.  To make it simple I took the dihedral out.  I went out the next evening and low and behold the model actually flew considerably better.  Control inputs were sharper.  Turns were more consistent.  Aerobatics seemed more solid.  Within a week or so I had changed to a larger motor, reduced the wing’s angle of attack and added 1” to the ailerons.  Each change increased the performance.  Over time the ugly wing splice did not seem so ugly.  I actually started to like it and it did really work well, especially with the larger motor.  The reinforced splice became a design feature to be incorporated in all future wing modifications. 

 

Well, so much for how we got here.  Here are a few more shots:

 

DESIGN CONSIDERATIONS: 

1. Efficient use of materials: The fuselage and tail uses the full width and length of 2 sheets of DTFB joined on 20" sides with very little waste.  Each wing uses one full sheet of DTFB on a no waste basis. Wood parts use one 6" X12" sheet of 18" lite ply with no waste.  Misc. Parts use another 1/2 sheet of DTFB with very little waste. 

2. Conventional high wing monoplane appearance.

3. High lift, short take off wing.

4. Larger size for gentler handling.

5. Large full length ailerons and large tail control surfaces for responsive aerobatic performance.

6. Standard FT power pod with tabs removed for ease of equipment service.

7. Battery at CG to allow large latitude in battery size for longer run times.

8. FT style under cambered wing tips for tip stall control.

 

DEVELOPMENT MODIFICATIONS:

This is the fourth build with a few refinements along the way:

1. On the original fuselage design I had placed the tail plane too low.  It was in the wing wash. I cut and reshape the original fuselage to test the concept then redesigned to the current arrangement.

2. The original ailerons were 1 1/4" wide and were less responsive than desired.  I redesigned the wing to still be a one sheet no waste component with ailerons increased to 2 1/4".

3. The original motor was a D2826-6 2200 kV from Hobby King with maximum power of 342 watts.  I changed to a L3010B 1300 kV also from Hobby King with 420 watts.  The power increase was significant.

4. The original wing failed performing tight aerobatic maneuvers under full power.  I reinforced the center of the wing with top and bottom wing doublers to hold up to the extreme loads.

5. The original nose was one layer of foam board.  I widened the nose 3/8" and added nose doublers to strengthen it.

6. The original horizontal stabilizer curled in the sun.  I added two dowels to stiffen it.

7. The original vertical stabilizer warped in use.  I added a leading edge dowel extending to the bottom of the fuselage to stiffen it.  I also extended the back end down to sandwich between the fuselage sides,  

 

 

Here are a few more detail photos:

 

The Nose:

 

The Windows (duct tape):

 

Tail Feathers:

 

Tail Servos:

 

The Tail Skid:

 

The Power Pod:

 

Top Wing Doubler:

 

Bottom Wing Doubler, Centering Blocks & Hardware:

 

Wing Bottom Details:  Black(duct tape) and Full Length Aileron: 

 

 

PLANS DEVELOPMENT:

A while back Bob McBride contacted me expressing interest in building my 80" No Waste Flying Wing.  He had a couple of questions about missing or unclear dimensions.  He sent his questions in the form of a multi color digital drawing.  Now I am thinking, “I wish I could do that!"  We went back and forth a couple of times.  He ended up with a nearly complete drawing in very short order and offer that I could use it as my own when it as done.  I replied that I would like to offer it to the community but would only do so if his work was properly credited.  I told him about my predicament regarding the trainer and suggested that we could partner on it.  "Designed by: Dan Harkless  Drawn by: Bob McBride". He graciously agreed.  

For the last several weeks we have been working on the drawings, learning each other's methods and working out the details. I think we are ending up with a pretty good set of plans.  Our results will be attached below.  You can be the judge.

 

PLANS:

These plans are pretty complete. They use standard FT building methods.  I believe a very experienced builder could build successfully just from the plans.

 

The following are large full sized sheets.  They can be printed as tiles using "Poster Print": 

Fuselage 1 

Fuselage 2

Right Wing

Left Wing

Misc DTFB Parts

To "Poster Print":  

     1. Click on the drawing to open it.

     2. Left click and "Save As".  Select location and save.

     3. Go to the saved location and double click to open the file.  

     4. Click "File" /  "Print" / "Poster"

     5. Set Tile Size 100% and Portrait

     6. Click "Print"

(Tiled drawings to be added soon) 

 

The following are 8 1/2 X 11 sheets that can be printed directly: 

Wood 1

Wood 2

Spars 1

Spars 2

Windshield

Side Windows

Main Gear 1

Main Gear 1

Tail Skid - 8 1/2 X 11

Wing Centering Blocks - 8 1/2 X 11

 

 

BUILDING SEQUENCE: 

I am including a Building Sequence narrative below.  It is pretty lengthy so I am including it as an separate file. Moderately experienced builders should be able to follow the plans and building sequence for a successful build.

Update 1-25-16: I have revised the Building Sequence reversing the order of installing parts "G" and "H" based on a suggestion from jalkin to make the installation of "H" easier.  Thanks to jalkin for the good suggestion.  (This is the second revision.  This one is correct.)

You can click below to open then print the Building Sequence file.

Building Sequence 1-25-16

(End of update)

(Note: Additional details may be added later) 

 

SPECIFICATIONS:

Type: Single motor high wing (cabin) monoplane

Landing Gear: Tail dragger with steerable tail skid 

Wing Span: 60"

Length: 45 1/2"

Weight: 1580 g (3.5 #) with 5000 3S battery; 1400 g (3.1#) with 2700 3S battery.

Wing Area: 4.55 SF

Wing Loading: 12.4 oz / SF: 10.8 oz / SF

Power:  420 W @ 120 W per #; 135 W per # (Hobby King L3010B -1300 kV)

Maximum Thrust: 1800 g (tested) w/ 9050 prop.

 

Running Gear:

Motor: Hobby King L3010B- 1300 kV 420W, 1650 g thrust

Prop: 9050 or 9 X 4.7

ESC: 50 A with UBEC

Battery: 2200 20C 3S to 5000 3S (Wide range because it is located at CG)

Servos: (4) 9g

 

Flight performance:

There are two wing options that can be built.  The version in the pictures is the advanced trainer with a straight wing.  An optional intermediate training wing can be built with about 5 degrees of dihedral.  This would be a good first aileron trainer. 

Take off distance is short, as little as 15' to 20' on grass.

Climb rate is fairly quick but not straight vertical with this motor.  It will climb at over 45 degrees.

Overall flight performance is pretty impressive with the suggested motor.  It has sharp responses to control inputs. It is capable of either extended slow and easy flight or a full range of aerobatics.  It does fairly large to very tight loops, sharp to slow and easy rolls, inverted, hammer head stalls, etc.

I have had flight times of 15 to 20 minutes with two 2700 3S and still had about 30% to 40% battery life left.  That was with the throttle set at anywhere from 35% to 100% doing aerobatics mixed with some slow and easy flying around.    I have not yet had the patience to do a long duration test but I believe I could get between 30 and 45 minutes going easy with this set-up.

It is very easy to fly yet has considerable aerobatic capabilities, an ideal combination for a trainer.

If you are looking for a model that looks like and flies like a  real airplane in the air and has flexible training capabilities from intermediate to advanced skills this could be the plane for you.   

 

COMMENTS

jalkin on January 20, 2016
Firstly, why did I have to register to this forum, though I was already regitered with the general Flite Test forums?

I'm busy building the Stout, and I'd like to suggest an improvement to the Build Sequence.
Change it so that parts G and H+H+H+H are installed BEFORE part G. Once G is installed, it makes it very awkward to install the other parts underneath it.
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dharkless on January 20, 2016
Hi jalkin,

Thanks for your interest in my design.

I don't know about the registering issues. You might want to contact FT about that.

I do see your point about the Building Sequence. It definitely would be easier tho install the "H" parts before "G". I have updated the article with a revised Building Sequence including your suggestion. Please let me know if you run into anything else as you build.

I started a Forum string under "Electric Fixed Wing Aircraft" for builder comments and suggestions and included your suggestion.

Please send progress photos : dhark69@gmail.com
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dvx216 on January 11, 2016
Just getting into the hobby so I decided to cut my teeth on building the Stout wing trainer.Here in northern Ohio this time a year what else are you going to do.So far so good on the build.I have built balsa wood boat so this media new to me. Foam board is cheap so I don't mind my screw ups so far.I'm getting the hang of the method of flite test type plains .The wing took me a while to figure out but I got one side made the next one should be a breeze.


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dharkless on January 12, 2016
I wrote the article showing the medium to advanced trainer but my first prototype was actually set up as a beginning aileron trainer. It could actually be set up as a 3 channel trainer as well. There would be a couple of changes needed to do that. The wing would need more dihedral and you would have to give it more angle of attack. I could walk you through it if you are interested. The changes could all be made in the wing so you would still have the medium and advanced trainer if you make the wings shown on the plans.
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dharkless on January 12, 2016
Good luck with your build. This can be a first trainer if you have a lot of simulator time on ailerons but is a better second plane. Most people start with a 3 channel plane without ailerons. Feel free to contact me with any questions yo may have: dhark69@gmail.com
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Markm82 on December 11, 2015
This is something I've Iooked for. Been looking for a trainer for a family member. Putting this on my build list!
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dharkless on December 12, 2015
Thanks for your interest.

If you are impatient you can save the full sized drawings to a document folder and then open them and "Poster Print". We should have tiled plans up in a couple of days.

Bigger trainers ARE easier to fly. Everything happens slower.

Contact me here with progress or if you have any questions.

Send pictures to: dhark69@gmail,com



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dharkless on December 12, 2015
That e-mail is dhark69@gmail.com.
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jordy123 on December 12, 2015
Me, I like the plans.
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dharkless on December 13, 2015
Thanks. We tried to include all of the parts and location information on the plans so an experienced builder could build just from the plans. For less experienced builders or if there are questions the narrative should fill in the gaps.

Give it a try and let me know what you think.
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Izzak on February 14, 2016
Would you have any photos of how the landing gear is assembled and installed ?
Thank you for your time & thank you for YOUR OUTSTANDING Storch build..
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dharkless on February 15, 2016
Hi Izzak,
Thanks for your interest in my Stout Trainer and your kind comments.
I currently do not have any photos of the process of making this landing gear. I will try to get some and do an article update sometime this week.
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jalkin on February 17, 2016
Can I ask a question that isn't directly related to the Stout, but more general in nature?

I have built the Stout with the intention of it being a low-cost introduction to RC. I have other models in mind for when I'm more proficient. Now, I need some help to equip the model, as this is my first foray into the RC world, and I can't find anybody else in my area who can help. I need everything from transmitter to batteries and servos. I thought this would be easy, but having read the reviews on http://www.rcmodelreviews.com I have information overload, and I'm totally baffled. I have bought a motor (Turnigy 3010B - 1300KV, 420W). Here's what I need help with...

Propeller. I see you're using a 9050, but I'm having real problems sourcing one. HobbyKing has them - but in Hong Kong, which can be anything up to 5 weeks away. Anyway, that's my problem - a bridge to cross!

Battery. I have read a LOT on this subject, and was on the point of ordering a 3S LiPo, but ModelReviews recons that while 3S is good for the motor, the voltage is too high for the receiver. He says "Since a two-cell LiPo produces 7.2 volts, a regulator is essential or it's very likely the servos will be damaged through overheating. Given the fire danger and other risks associated with LiPo use, I can't really recommend that you use LiPos for your receiver packs -- the extra complexity simply adds extra things to go wrong." This was unexpected to me, as the servos have no information about voltage with them. It stands to reason, though, that they and the receiver can only take so much voltage. Do I need more than one battery in the model?

Servos. Looking on Ebay with no real knowledge of the subject, I chose the TowerPro MG90S metal-geared servo. The sales spec reads OK, but ModelReviews says TowerPro is the worst he has had the misfortune to encounter, and while me might use one on a car, he wouldn't risk a plane by using one in the air. What's your take on it?

Transmitter - the Turnigy 9XR Pro also has a good sales spec - but two of the reviews in HobbyKing are definitely not good - failures, and a lot of after-sales support difficulties. I don't want to spend £50 on a transmitter now, only to spend £200 on one in a few months when I've got further into the hobby, so would I do better to go more expensive now? I have read good reviews on Futaba - though it costs more. What's your recommendation?

I thought of putting a flight stabilisation electronics module into it. Can you offer any insight?

Can anybody please give me a list of what I need, complete with make and model where possible, and how to connect it all - then I can go out and source it all, and maybe be in a position to crash it in 6 or 8 weeks' time.
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dharkless on February 18, 2016
Hi jalkin,

Thanks for your interest in my design.
I can tell you how I would handle these issues.

Propeller: I would find a couple of 9 X 5 propellers on Amazon or eBay for quick delivery and then get a larger quantity from HK Global. I am in the Eastern US. I have ordered items from HK Western Warehouse and from Global the same day and gotten them less than a week apart. Deliveries from Global probably average 3 weeks.

Batteries: The power for the receiver does not come directly from the Lipo battery. The speed control connects to the battery. There is a circuit in the speedcontrol that powers the receiver. The servos plug into the receiver from which they get their power. You need a speed controller (ESC) with a receiver power cable (ubec).
Batteries need to be sized to the use. I use 2650 to 5000 mah 3 cells.

Transmitter: I use a FlySky FS-i6 radio. It has 6 channels, 20 model memory and telemetry (data sent back from the model). The radios are under $60 US and additional receivers are under $15. Turnigy TGY-i6 is the same radio with slightly different software and similar cost. These radios have features and performance similar to many $200 - $300 radios.

I have never used flight stabilization. If you can get something that returns you to stable flight from being out of control I suppose it might make learning easier.

Servos: I use the cheapest 9g servos I can find. HK has several selections under $3. I have gotten most of mine for $1.55 of less bidding on eBay.I have built over 50 planes in the last three years using these on most of them. I have only had 2 or 3 duds and only one in-flight failure. I have not noticed any difference between the ones from HK and eBay.

I will try to get links added for the gear listed in the article by this weekend.

These are general answers.

If you need more specific answers send me an e-mail at: dhark69@gmail.com. I can walk you through the set-up.
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jalkin on February 18, 2016
That's an excellent and comprehensive answer, dharkless. Many thanks for it.
I *would* like some extra info, so I'll e-mail you as suggested.
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dharkless on February 18, 2016
The Turnigy radio is from Hobby King.
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Stout Trainer - Mid to Advanced Trainer - Preview