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Sisu 1A Project

Old 09-24-2018, 07:32 PM
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mmartin55
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Default Sisu 1A Project



I am presently collaborating with several modelers to develop and build some new and unique aircraft. More information about myself and the current projects may be found on this thread and by searching my name and adding Sisu 1A. I will be cross posting from another forum that has an active thread I've participated in for more than 12 years on the development of a kit for the Leonard Niemi Sisu. If not familiar with the aircraft, it is an aluminum and composite sailplane built in the late 50s that set more records than any other single sailplane in history. A search of the web will lead you to many great historical overviews so I won't add those to this discussion.

I've completed what I feel to be very accurate three views with the aid of Mr. Niemi's drawings and data and my collaborator is using Solidworks to simplify the parts development with several key goals:
* Best fit and finish to achieve first a 1:5 scale model, scaleable to other spans;
* Use a laminar flow airfoil if appropriate and suitable;
* Maintain scale fidelity to the original design;
* Provide a simple and accurate build methodology that is both robust and with very low drag;
* Build at or below 90 oz. (120" - 3.048m span and approximately 640 sq. inches of wing area);
* Gather ideas and information from others on approaches to details and parts selection for retractable gear, slotted flaps and nose releases, etc.;
* And mostly have fun designing, building and flying what I consider one of the most beautiful aircraft in the world and get the best possible performance from her.

If you are not familiar with my work as I have been inactive here for some time, you may visit this and other sites to get a glimpse of past projects:
The Aerosente Glider Workshop: June 2009
Thanks, Tom

Last edited by mmartin55; 09-25-2018 at 03:45 AM. Reason: Add images
Old 10-04-2018, 05:38 PM
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mmartin55
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More of Richards work in SOLIDWORKS®. Currently working on airfoil choices to extrude the shape of the wing, spar and rib design and construction, and how to create a scale and working slotted flap in addition to the spoilers. I will be working on development of the scale tail section assembly cross sections and attempting to source photographs or drawing documentation of the flap attachment and actuation and how that is integrated into the wing assembly.

If you have comments or recommendations for airfoil sections, please add them here or at the FB page so they can be considered and replied to by the group. https://www.facebook.com/groups/328980957873890/

Thanks
Old 10-25-2018, 07:58 PM
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udithag
 
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Hi friend, good luck for your project. Can you please give me the wing area and the total weight of the aircraft that you refer? I am doing a survey and collecting data.
Thanks
Old 10-30-2018, 09:45 AM
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RHX1138
 
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Originally Posted by mmartin55 View Post
If you have comments or recommendations for airfoil sections, please add them here
What is the root chord length, tip chord length, and total span, and I'll give you airfoil recommendation. I will always suggest at least -.75 degrees of twist.
Old 10-31-2018, 10:16 AM
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RHX1138
 
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Default Airfoils

Here is 2 custom designed airfoils I made for you. Use these if your going for good all around flight on the slope. They are DAT files from XFLR5. Use -.75 to -1 degrees of twist and you should be good.
Attached Files
File Type: zip
3M GLIDER AIRFOILS.zip (3.6 KB, 24 views)
Old 11-02-2018, 05:09 AM
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mmartin55
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Thanks for your replies. You can find our Facebook page on the development here: https://www.facebook.com/groups/3289...?ref=bookmarks.
Sorry for my missing your posts and not replying. We've decided to go with airfoils from the HQ series and without twist to the wing as in Leonard Niemi's original design. The root dimensional data you are requesting can be determined from loading the three views at the 1:5 and 1:4 scales and adjusting using the full scale span of 50 feet for scale factor.

Currenlty working on the retractable landing gear mechanism to meet the requirements of the Sisu most effectively and efficiently.

Tom
Old 01-11-2020, 09:07 AM
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mmartin55
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Default Update to 1:4 Scale


Fuselage interior aft of pilot seat, full size Sisu 1A, last number in serial production.
I've enlarged and renotched the parts to 1:4 scale and 5/32" thick aircraft ply. Fuselege ply parts use one 12" x 48" sheet of goods. They've been sent to the cutter and will soon be on the bench and hope to make a video of the assembly order and process while I also work out the details for the wing mount, instrument panel pedestal and landing skid mount as well as V-tail subassembly for de-mountable empenage and actuation linkage routing. Should be the simple part of development compared to the initial three views and fuselage frame. I've also created the root and tip wing ribs per original full size airfoil profiles and extruded the complete set of wing ribs, less the lightening truss cutouts. They've been notched for typical spars from cap and shear but still need to add the drag spar/aileron/flap location and assembly parts details as well as the location of the servos. Tom

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