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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!