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1/3 scale Japanese vintage glider Mita type 3

Posted: 14 Nov 2019, 11:00
by norm
I'd like to post my newest scratch build 1/3 scale Japanese vintage glider Mita type 3 mod1.

Image

Above picture was taken at her first flight 19th Sept. 2019. I will post its details and how I made it during last 2 years. Please enjoy!

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 14 Nov 2019, 11:53
by VinceC
Lovely glider and one I don't know anything about. Thanks for posting

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 14 Nov 2019, 22:35
by Martin Gough
Fantastic. Like that.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 15 Nov 2019, 02:00
by norm
Cliff,VinceC and Martin, thank you for your comments.

Cliff, yes I also don't like the moustache. It does not fit her beautiful face but is necessary because I don't have a Tag nor a Winch.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 15 Nov 2019, 10:02
by norm
About the Mita type 3 mod.1.

Believing that the Mita type 3 is not popular in the Europian glider community, let me introduce her.

The Mita type 3 mod.1 was designed by Mr. Asahi Miyahara in 1965 and took the first flight in 26th March, 1966.
It is two placed soarer used by many flying clubs and brought up many glider pilots in Japan.

General characteristics
1. Crew 2
2. Length 8.60m
3. Wing Span 16.0m
4. Height 1.3m
5. Wing Area 15.9m^2
6. Aspect Ratio 16.1
7. Airfoil NACA 633-618
8. Empty Weight 300Kg
9. Gross Weight 450Kg
10. Number of Production 32

Performance
Vne 180Km/h
Max glide ratio 30.8
Rate of sink 0.75m/sec

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 15 Nov 2019, 10:04
by norm
Cliff, yes I made the plan by myself using 2D CAD.

My 1/3 scale Mita type 3 has 5.33m wing span and the all-up weight is just around 10Kg. It has a fuselage made of epoxy bonded carbon pipes and covered with the SIG KOVERALL. The original Mita's fuselage is made of welded steel pipes and covered with cloth.

Because the 1/3 model craft's Reynolds Number is much lower than the original Mita, I changed the NACA 633-618 18% thickness airfoil to the NACA 632-615 airfoil which has 15% thickness. It was decided after the study of airfoil characteristics change at low Reynolds number by using the XFLR5 software.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 15 Nov 2019, 16:12
by Paul_Williams
Wonderful modelling of something not seen here before.
Will you post how you made the tube joints strong enough ?
Most impressed.
Paul

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 15 Nov 2019, 17:33
by StephenB
Beautifully engineered fuselage, quite an accomplishment - interested to see how you did this.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 16 Nov 2019, 02:47
by norm
Cliff,
It is my pleasure and a great honor to donate the plan but the current plan is quite messy. After organizing it I will donate. Please wait.

Paul and Stephen B,
The fuselage structure was made of carbon tubes bonded by epoxy adhesive. After cutting the tubes, edges were trimmed carefully by a diamond file to fit well. The fuselage is composed from several truss panels. Each panel was built on a flat plate onto which the plan was placed. Attached is a shot of making a panel.

At this point, a bit of CA is dropped on each junction. After making necessary panels, then they were constructed. Second photo shows this process.

A bit of CA is dropped again. After the construction is completed, the epoxy adhesive is applied on each junction. The epoxy adhesive was mixed with a carbon powder.
The canted longerons were joined each other with a steel rod inserted inside with the epoxy adhesive.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 16 Nov 2019, 11:55
by Martin Gough
Stunning construction. More picture of the build would be greatly appreciated.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 16 Nov 2019, 12:50
by norm
Martin, thank you for your comment. You can see more picture in my blog. Although it is written in Japanese, you may possible to understand by viewing pictures. Please try!

http://normsan.blog.fc2.com/archives.html

Added by moderator

For English Translation:
https://translate.google.com/translate? ... hives.html

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 16 Nov 2019, 12:55
by norm
Let me show you my 1/3 scale Mita's beautiful flight over the rice fields. This view is taken from a drone.

[youtube][/youtube]

I belive the scenery is quite different from those of Europe. Did you enjyoy it?

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 16 Nov 2019, 13:32
by Adam C
I've used a similar approach with Ww1 scale power models that used wooden dowel to emulate steel tubing. The idea is interesting but suffers from easily cracked joints even with pining.

Thin walled steel tubing is practical and can be welded.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 17 Nov 2019, 07:54
by norm
Wing Build

The wing is composed of four sections, 2 center sections and 2 outboad sections. The full scale Mita has a single center section but I have broken it in two sections because of ease for transportation. It has a single spar at 35%C and an auxiliary spar in front of the airlon. The spar was built with a square carbon tube frange and a plywood web.
Each section was built on an assembly jig. Total weight of the wing is about 4 Kg after covering and painting.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 17 Nov 2019, 09:52
by RobbieB
Super vids (and model) Norm - always nice to see something a bit different.

Quite a 'tight' flying field you have there but I suspect Rog would still be a bit envious :lol:

It will be interesting to see how the epoxied joints stand the test of time re Adam C's point - do please keep us informed.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 17 Nov 2019, 13:41
by norm
Adam C and RobbieB, Thanks for your comments. I will check the epoxied joints before every flight and inform you if anything wrong would be found.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 17 Nov 2019, 19:40
by Jolly Roger
What a beautifully engineered model and a really atmospheric video. I love the long shadows and rich sunlight of early morning / late evening.

Yes that landing area is a little cosy! But the model was flown very skillfully.

I experimented with gluing carbon tubes together for my 1/3 scale cub undercarriage and found the joints far too fragile for the shock of landing loads, so I created the strength from the carbon tows and epoxy pulled through the tubes. However I think in a large interconnected frame like your fuselage, the parts support each other so I think it may be strong enough.

One last thing - I hope you took great care to avoid breathing in the carbon dust as it is highly toxic. :)

Thanks for posting.
Roger

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 17 Nov 2019, 21:59
by Jolly Roger
Some further info on the Mita...

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 18 Nov 2019, 14:21
by norm
Rojer, Thank you for your comment.
Yes our field is small because Japn is composed from small mountainious islands. There is little open space.
How I want to fly my models in Europe!

Norm

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 19 Nov 2019, 13:24
by norm
Landing Gear
The Mita has a landing gear which has a single wheel supported by two rubber shock absorbers. I simulated it in my model.
Attached, you can find the drawing, parts cutted from carbon sheet/pipe and the assembled gear.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 20 Nov 2019, 08:02
by norm
Horizontal Tail

Horizontal tail of the 1/3 Mita is a quite conventional one, made of balsa ribs and spars. The stabilizer is planked with balsa sheet. The elevator has diagonal ribs and is not planked. Right elevator has a dummy tab. Elevator hinges are made of carbon plate, acrylic plate and bamboo rods. Both stabilizer and elevator were build on the jigs.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 21 Nov 2019, 11:00
by norm
Elevator Control Sys

The elevator control system of the original Mita is a linkage half by rods and the rest by wire. There are two bell cranks, one at the middle and the other at the end of the fuselage. Two rods connect the pilot sticks and the foward bell crank. Between the bell cranks there is a wire linkage and the elevator is connected to the aft bell crank by a connecting rod.

My 1/3 scale model simulates this system. A servo is placed under the aft pilot seat and connected to the linkage rod. Thus the control sticks moves for and aft in accordance with the elevator up and down.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 23 Nov 2019, 01:22
by norm
Vertical Tail
The vertical tail of the Mita has similar structure with the horizontal one, planked fin and non-planked rudder with oblieque ribs. In the 1/3 model, these are all made of balsa except the fin spar which is made of cypress. The rudder has two hinges, mid and bottom, and it can be put on/off the fin easily. Both the fin and the rudder were assembled on jigs made of balsa.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 24 Nov 2019, 06:24
by norm
Rudder Control Sys
The rudder control system has a conventional wire linkage. There are four turnbuckles, two in between the front and aft pedals and two in between the aft pedals and the rudder. I made these turnbuckles from 5 mm dia bruss rod. The pedals are made of bruss tubes. The rudder servo is placed just after the front pedals and is linked with them. It works as the pilot feet. Behind the servo there is an instrument panel, so the servo can't seen from outside.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 24 Nov 2019, 17:23
by MDev
I like the thinking behind this fuse structure, I’ve made a tail out of Airex and carbon sandwich glued with epoxy and sailing masts out of carbon tubes With jumper struts in a similar fashion, they’re holding together still after 15 years or so. I wonder how resilient the structure is and do landing forces pass through it to the built up wings? Time will tell.

M

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 25 Nov 2019, 03:53
by norm
Cliff, yes it is a pity for me too that I can't show you my model and fly it over the beautiful scenary of the U.K.
I have been in the U.K. several times and love the scenary of the Cotswalds best. How I hope my model flying over the gentle hills there!

norm

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 25 Nov 2019, 04:27
by norm
MDev, thank you for your comment. It is interesting that there are many modelers who have interest in my carbon truss structure. I glued it with carbon filaments mixed epoxy and attatched a small carbon plate where the stress seems high.
Yes the landing loads may be the most severe one but they make compression at the truss joints. Epoxy glued joints are week for the bending or tension stress but they endure for compression stress much better. So far they look working well but, as you say, time will tell the truth.

norm

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 25 Nov 2019, 07:22
by norm
Aileron
The ailerons of the Mita are the frise type one. They also have a differential too. It was very time consuming task to design the rib contour because the base wing airfoils are defined parallel to the air flow, but the aileron ribs are placed diagonally to the wing span. If I could use the 3D CAD it would be easy task but because my CAD is 2D, it took time.

The ailerons have mass balances. I made them with aluminum tube and block. The real Mita's ailerons are linked with the sticks but in my model ailerons are linked with the servos placed in the wing, so the sticks are free laterally. I used a small dummy servo connected to the stick longitudinal shaft. It prevents the sticks from lateral free movement and moves them when the ailerons are moved.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 25 Nov 2019, 09:00
by Peter Balcombe
Norm,
Amazing attention to detail and very good engineering skills.
Very well done indeed.
Peter

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 26 Nov 2019, 04:56
by norm
Peter, Thank you for visiting my thread. I will post more details and hope you will enjoy them.

norm

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 26 Nov 2019, 05:41
by norm
FWD Fuselage
As many guests have interest in my model's fuselage construction, I will post its details in order. This time topic is the FWD fuselage.

Mita's FWD fuselage is made by several truss panels. These panels are flat but they are assembled with angles each other.
So, an assembling jig is required. I made the jig using wood bars and plates. This jig is also useful to construct the landing gear support structure and to joint the FWD and AFT fuselages. Be careful that attached photos show the structure before epoxy glueing.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 26 Nov 2019, 09:35
by VinceC
Incredible research and attention to detail. Excellent work

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 26 Nov 2019, 19:43
by Jolly Roger
You have made some very beautiful and elegant structures. I can imagine the fuselage must feel very light and stiff.

If the joints between carbon tubes are strong enough to take the model flying and landing loads, I think many people will be interested in trying this method. Carbon tube can be bought cheaply on eBay and from HobbyKing.

I would like to hear more about how you glue and reinforce each join, for example, do you make your own carbon powder? And do you insert any material inside the tubes at the joint?

Thank you again.

Roger

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 27 Nov 2019, 05:20
by norm
VinceC and Jolly Roger, Thank you for your comments.

Jolly, I used the carbon powder available from retailer and mixed it with epoxy glue. Although it is named "powder", it contains small carbon fibers and if you mix it with epoxy glue it becomes CFRP. It is very tough and light. Weight of the completed basic fuselage I posted yesterday is only 710g nevertheless its length is over 2m. It is very rigid too.

Carbon pipes are jointed with a short piano wire inserted and glued by epoxy where possible, but most joints are just epoxy bonded only. Those joints that seem to be important are bonded with a small carbon plate for reinforcement. The wing support beams are tied up with the longerones by carbon threads and glued. Please see attatched pictures.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 27 Nov 2019, 12:00
by norm
Tail Wing Mounting brackets, Tail Skid and the Elevator Bell crank
The horizontal stabilizer is mounted with three M3 bolts through carbon pipes placed on the AFT fuselage. The vertical stabilizer is mounted at the end of the fuselage with two M3 bolts.

The real Mita's tail skid is made of three ply of steel plates with an abrasive shoe. In my model it is made of carbon plates with an alminum shoe. These plates are not bonded each other for the maximum spring effect.

A bell crank made of carbon plate/pipe is equipped under the horizontal stabilizer which is connected with the elevator.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 27 Nov 2019, 12:31
by Peter Balcombe
Norm,
How did you cut the bellcrank plates?
Are they all made by hand, or do you have CNC cutting facilities?
Very good work anyway :)

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 27 Nov 2019, 12:54
by norm
Peter, I cut them by hand with a mini router which has a diamond saw. Then they were trimmed by a diamond file.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 28 Nov 2019, 02:34
by norm
Fuselage sub structures
The Mita's fuselage has sub structures around its rectangular main structure, the lower sub-structure, the upper sub-structure and the side beams. With these sub structures its cross section forms octagon when coverd with fabric. Both the upper and lower sub-structures are made of carbon pipes and the side beams are made of paulownia plates.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 29 Nov 2019, 06:59
by norm
Motor mount
This time I will show you the motor mount.

Why Motor? This may be a common question of the European scale glider fans. First of all I must explain the Japanese scale soaring enviroment. Japan consists of innumerable islands, lage and small, of which four islands are relatively large and most people live there. Total area of Japan is about 370 thosands square km. It is a little bit larger than Germany but, in contrast to Germany, its 70% area is mountainous and 2/3 are covered with forests. On these islads there live more than 120 million people. So there remain little spaces for model glider flying. Because of these enviroments, it is not common to use a tag or a winch that requires somehow a large space. It is common to install a motor and a foldable prop. By the way, because of limitted space, 1/5 scale models are called big and 1/3 scales are extra-big in Japan.

The motor mount of my model extends forward from the main fuselage and requires a special jig to build it correctly. The motor is mounted on a plate made of 9 mm thickness plywood. This plate is supported by carbon pipes and plates. A plywood plate is bonded on the upper side on which the ESC and a battery for the receiver will be installed later. The motor is FUTABA FMA-5065 KV300, 2000W class motor.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 30 Nov 2019, 06:18
by norm
Tow Release
There are two tow release equipments in the original Mita, for the aerotow and for the winchtow. The former is at nose and the latter is in front of the landing gear. I have no tag nor winch but I made these equipments for the model. They are not dummy but really work. These are hand made with aluminum plate. One servo actuates both. As the elevator control tubes pass through the center of fuselage, the winch tow release is attached on the port.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 01 Dec 2019, 10:00
by norm
Pilot Seats
The original Mita's pilot seats are composed of a curved wood seat, steel pipe legs and a fabric seat back. Top side of the fabric seat back is wrapped around an aluminum tube and this tube can be moved back and forth for requilining by changing two pins that fasten the tube with the fuselage structure. I simulated them with a curved plywood seat, bamboo rods legs and a fabric back. The aluminum tube is simulated with a balsa rod.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 02 Dec 2019, 13:27
by norm
Landing Gear Cover
To prevent air comes in fuselage through the gap around the landing gear, there are two kinds of covers. One is a wheel cover made of plastics and the other is a seal made of fabric. For my model I made the wheel cover with plywood and balsa and the seal with fabric.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 04 Dec 2019, 11:11
by norm
Miscellaneous Equipments
In addition to the pilot seats and the wheel cover, I added some miscellaneous equippments, such as the shoulder harness, AFT pilot's leg cover, control sticks, tow release knob, spoiler & blake lever, elevator trim lever, cockpit floor and the fuselage access cover.

Although, in actual Mita, the AFT pilot's leg cover,the FWD cockpit floor and the fuselage access cover are all made of aluminum plate, they are made of plywood or hard paper in my model to avoid the radio interference.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 05 Dec 2019, 18:05
by StephenB
Excellent detailing Norm, how did you make the harness and buckles?

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 06 Dec 2019, 09:39
by norm
StephenB, the harness is a wooven belt and the buckles are plastic buckle I bought both at a handicraft shop.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 06 Dec 2019, 10:17
by norm
Making the Nose Cowl Wooden Form
The Mita has a nose cowl made from GFRP. In my model I simulated it with glass cloth and epoxy resin. The process to make a FRP part is, 1st: draw a 3D plan, 2nd: make a wooden form, 3rd: make a plaster mold and finally lay up cloth and resin. Attached photos show the 1st and 2nd process I took. The wooden form is made of balsa.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 08 Dec 2019, 12:18
by norm
Making the nose cowl
A plaster mold was made with the wooden form posted above. It was painted with the mold release agent, then glass cloth was layed up with epoxy resin and cured. One day after the nose FRP cowl appeard. After trimming it was tested to fit with the fuselage structure and the result was perfect.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 09 Dec 2019, 18:38
by SedB
norm wrote:
08 Dec 2019, 12:18
Making the nose cowl
Thank you for this masterclass, looks great so far!

Daniel

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 10 Dec 2019, 05:25
by norm
Cliff, I checked the magazine 航空ファン(Aviation Fun) Jan/2020 edition but I could not find any page dealing with Japanese gliders. Could you please provide me the information source? Norm

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 10 Dec 2019, 05:38
by norm
SedB, Thank you for your comment. I hope you are enjoying my thread.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 10 Dec 2019, 05:46
by norm
Making the Wing-Body Fairing
Taking same process with the nose cowl, I made the wing-body FRP fairing. This is much easier than the cowl because of its simple shape.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 11 Dec 2019, 03:05
by norm
Cliff, sorry I made a misunderstanding. The article is titled "Unknown story of The 96 Attacker Unit" so I had regarded it does not deal with any glider. The article deals with former Japanese Navy's 96 attacker and states that the military transport glider Ku8-2 was towed by her. Although total pages are 8, only first half 4 pages deal with the glider, I scann and send 4 pages.
If you have any question or need my help, don't hesitate to ask me.

Following sites also deal with the Ku8-2.
http://military.sakura.ne.jp/ac/ku8.htm
https://ja.wikipedia.org/wiki/%E5%9B%9B ... 1%E6%A9%9F
http://www.topsid.com/index.php?war=jap ... saiku-8-ii
http://pwencycl.kgbudge.com/K/u/Ku-8_Gander.htm

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 11 Dec 2019, 04:10
by norm
Making the instruments panel
The instruments panel was made of 1.6mm thick plywood and the instruments cases are milled from aluminum bar. Instrument faces are drawn by CAD and printed on a photo quality paper.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 13 Dec 2019, 02:10
by norm
Making the wing tips
The Mita has wing tips with a small wheel each side. I made them with various thickness balsa sheets and miniature wheels.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 14 Dec 2019, 12:07
by norm
Canopy frame
The Mita's canopy is composed from two parts, front canopy and rear canopy. I made its frames with powlonia bar and plywood plate. The model canopy front frame has two hinges for openning/closing, a side bar and a lock mechanism. These are simulated those the real Mita has.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 16 Dec 2019, 11:22
by norm
Electrical Equipments Installation
Electrical equipments such as motor, ESC, receiver and its battery, S/W and power line were installed. I payed maximum attention they are not seen from outside but the power line could not be hidden.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 16 Dec 2019, 14:50
by StephenB
Cliff Evans wrote:
16 Dec 2019, 11:24
Very nice Norm. How did you make the belt buckles?
Yes, I was wondering that too .............

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 16 Dec 2019, 17:33
by RobbieB
Could they be little nylon snap catches that you have on haversacks and the like?

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 17 Dec 2019, 00:38
by norm
Cliff, StephenB and RobbieB, The belt buckles were bought from a handicraft shop. Yes, they are little plastic snaps you may find on harversacks as RobbieB guess. I have been asked about them by StephenB and answered on 06 Dec 2019, 09:39 on page 6. Sorry my english is not good and could not explain well. Norm

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 17 Dec 2019, 10:16
by RobbieB
norm wrote:
17 Dec 2019, 00:38
........'I have been asked about them by StephenB and answered on 06 Dec 2019, 09:39 on page 6......'
We all need to pay a bit more attention me thinks :lol:

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 17 Dec 2019, 13:24
by StephenB
RobbieB wrote:
17 Dec 2019, 10:16
norm wrote:
17 Dec 2019, 00:38
........'I have been asked about them by StephenB and answered on 06 Dec 2019, 09:39 on page 6......'
We all need to pay a bit more attention me thinks :lol:
Mea Culpa, I asked the question twice :?

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 18 Dec 2019, 10:32
by norm
Cliff, RobbieB and StephenB, Don't worry! It happens for me too. Norm

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 18 Dec 2019, 11:04
by norm
Tail cowling
The bottom of the leading edge of the Mita's vertical fin is cut off for mounting the horizontal tail. This area is covered with a plastic cowling. I made the cowling with PVC. But because I have no experience nor the apparatus to form the PVC, I asked a person who has both. He made the cowling with a wooden form I provided.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 18 Dec 2019, 21:37
by chris williams
Beautiful work, Norm...thanks for sharing

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 20 Dec 2019, 11:14
by norm
Covering & Painting
The wing and the tails were coverd with the ORATEX while the fuselage was coverd with the SIG KOVERALL. After beeing coverd they were painted with white acrylic paint spray.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 22 Dec 2019, 10:18
by norm
Completion of the canopy
The canopy transparency was made of PVC. I asked my friend who had made the PVC tail cowling to make it. He also made the canopy wooden mold with the plan I provided to him. After receiving the transparency I trimmed it and attatched it to the frame I had already made. With the canopy the model Mita became very realistic.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 24 Dec 2019, 07:27
by norm
Wing structural analysis
Because the 1/3 scale model is the biggest model I have ever built, I conducted the wing structural analysis to confirm its strength. The analysis was done on the Excel work sheet. The conditions of calculation are: Total weight=10Kg, Center wing weight=1.93Kg, Outer wings weight=2.0Kg. Ultimate load factor=7.5.

Attatched graphs show the loads/stress and deflection distribution of the half wing. Wing STA 0 is the center of the fuselage and Wing STA 1000 is the center/outer wing junction. Wing STA 2655 is the wing tip. Lift and inertia loads dicrease outside the Wing STA 1000 because the outer wing is tapered.

Wing tip deflects more than 110mm and the stress increases toward the wing root but it decreases suddenly at STA 1000. This is because the center wing has larger spar frange than the outer wing. The maximum stress is around 19 Kg/mm^2 which occures at the wing spar frange STA 100 where the wing is supported by the fuselage. The wing spar frange is made of carbon square tube which has allowable stress around 70 Kg/mm^2, so the maximum stress is well below the allowable.

By the way the outer and center wings are joined at the STA 1000 with a carbon tube which has 20mm outer and 16mm inner dias. The maximum stress of this tube is calculated as around 18Kg/mm^2 which also is well below the allowable 70Kg/mm^2. Thus it was confirmed that the wing has sufficient strength.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 27 Dec 2019, 11:20
by norm
Performance estimation
Before the first flight, I conducted the performance estimation of the 1/3 scale Mita. In contrast to the usual performance estimation where CL~α,CD~α,CM~α do not change with flight speed, they are changed with speed in my calculation because the Reynolds Number has a big effect in the 1/3 Mita's flight region. They are calculated by using the XFLR5. The glide ratio and the sink rate are calculated on the EXCEL spread sheet.

It is estimated that the maximum glide ratio is 22.5 and the minimum sink rate is 0.48m/sec for the weight of 10Kg condition. The real MIta's maximum glige ratio is reported as 30.8 and the minimum sink rate is 0.72m/sec.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 30 Jan 2020, 10:56
by norm
DWGs
Attached are the 1/3 Mita drawings. I want to donate these drawings to the SSUK. If you have any question please contact me by e-mail.

Re: 1/3 scale Japanese vintage glider Mita type 3

Posted: 30 Jan 2020, 12:10
by Cliff Evans
On behalf of the community, thank you very much, Was getting a bit worried about you as you had not posted for a while!

For acrobat to display the fonts included in the pdf files you will need to download the file attache in this thread and change the file extension to .msi and install the font pack. Easy Peasy!