Polen Special, anyone?

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harrisonaero

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Oct 31, 2009
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Coeur d'Alene, ID
As a suggestion... as you do each item take the opportunity to research and learn the theory behind the concept and then model accordingly. For example, on your NACA duct make the outside corners sharp (that's how submerged inlets work- creating vortices off the edges), make the shape of the wall curve exactly to theory, the ramp angle correct, the lip the right airfoil, etc.

Same for: wing airfoil, twist, incidence, decalage, etc.

You'll learn a tremendous amount of aerodynamics this way and end up with an accurate model.
 

mike_t_12

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Mar 7, 2010
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Los Angeles, Ca
Sorry 208Caravan, as far as I know, there were never any plans released.

Thanks Harrisonaero. I did some quick checking and it’s back to the drawing board! The shape and dimensions were taken from a template diagram so those are fairly close. The other details need some work. There’s a lot going on for what looks like a straightforward simple part.

In the above pictures, the wings, elevator and rudder are notional. The cockpit will fit a 6’3” 220 lb. guy which coincidentally is about my size!

I just finished Dan Raymer’s “Simplified Aircraft Design for Homebuilders” and am brushing up on my 3d math. Lots more work to do in these areas but it’s all good stuff. If it has anything to do with airplanes… I like it!
Mike
 

mike_t_12

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Mar 7, 2010
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I had some luck with the wing fillet this weekend. Next weekend, I'm going to work on the portion of the cowling between the spinner and fuselage and maybe the NACA duct.
Mike

wing_fillet_1.jpgwing_fillet_2.jpgwing_fillet_3.jpgwing_fillet_4.jpgwing_fillet_5.jpgwing_fillet_6.jpg
 

mike_t_12

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Mar 7, 2010
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I just finished the nose cowl - air inlet. Had a lot of trouble with this one and discovered many ways that don’t work. There are still some problems but for now, stopping on this version.
Mike



nose_cowl_1.jpgnose_cowl_2.jpgnose_cowl_3.jpgnose_cowl_4.jpginlet_walls_random_colors.jpg
 

flyvulcan

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Adelaide, Australia
That's looking very nice Mike. Keep at it. I'm sure there are many who would like to see the Polen Special "reproduced".

Dave
 

mike_t_12

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Thanks Dave.

I meant to say I was stopping work on this version of the nose cowl – still lots of work to do. I’m probably spending too much time on the modeling but it keeps me out of trouble. Well… not out of trouble with my wife for spending so much time on this!

Mike
 

mike_t_12

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Mar 7, 2010
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I worked on a new version of the rudder over the weekend. In the pictures below, the old version is on the left. In the old version, the highlight flattens out as it moves down away from the tip. In the updated version, the highlight is more rounded similar to the tip profile. I plan to make the same updates to the wing and elevator tips.

Mike


rudder_rework_1.jpgrudder_rework_2.jpgrudder_rework_3.jpgrudder_rework_4.jpg
 

f104asa

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Oct 2, 2012
Messages
5
Location
ITALY TREVISO (NEAR VENICE)
Hi All,

I recently switched from Rhino 3d to Alias... here are some screen shots from inside Alias (wire frames) and some test renders. I just found some mistakes I made setting up the initial spline curves so I'll have to go back and make some changes. For the next version, I plan to add more details like wing tip lights, Pitot tube and cockpit interior. No more black canopy to hide the empty interior!

Mike
Ciao Mike
i build and fly midget mustang in italy
i love polen special and i want to to draw it
i just to draw the center section because the wing and tail section is nearly the same of midget mustang
did you have some drawing ?
i like you 3d .....what cad 3d did you use ?
i am drawing in 2d all the parts
you are doing a good job
this is my web site
Untitled
Email aiyebe@tin.it

ciao daniele beltrame
 

N111KX

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Apr 18, 2011
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Location
Atlanta, GA USA
Looks like she had a fender bender...

IDENTIFICATION Regis#: 11DP Make/Model: EXP Description: SPECIAL II Date: 11/03/2012 Time: 2229 Event Type: Incident Highest Injury: None Mid Air: N Missing: N Damage: NoneLOCATION City: GRANBURY State: TX Country: USDESCRIPTION AIRCRAFT FORCE LANDED IN A FIELD, NEAR GRANBURY, TXINJURY DATA Total Fatal: 0 # Crew: 1 Fat: 0 Ser: 0 Min: 0 Unk: # Pass: 0 Fat: 0 Ser: 0 Min: 0 Unk: # Grnd: Fat: 0 Ser: 0 Min: 0 Unk:
 

GNXUS

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Apr 14, 2013
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London UK
Hi,
I'd just like to let you know that a builder (not Dick) of the plans-only design by Dick Eaves, the Nexus Mustang, is proposing some mods that make the Nexus Mustang look something like a Polen Special. He is proposing a bubble canopy, making the tandem two seat configuration into a single seater and possibly constructing a retractable gear. He is a structural engineer and and is willing to share design drawings. He is a member of the group I moderate on Yahoo. There are photos there of the three Nexus Mustangs built by Dick Eaves, two tandem and one side by side version plus his Midget Mustang.

You can join that group if you want to watch for progress. NexusMustang : NexusMustang

nexusmustang dot com

You can buy plans here for the original Tandem version of the Nexus. Dick is in London, Ontario.


Gary
London UK
 

mike_t_12

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Mar 7, 2010
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Los Angeles, Ca
Here are some renders of the version 4 model. I wanted to see how it looks before moving on to the 5th version. What do you guys think?


I've done a 1st pass through Raymer's Simplified Aircraft Design and I'm going through the Jon Roncz and Neal Willford articles/spreadsheets. Lots of good information to take in but kind of overwhelming. Along with all of the HBA forum information, it's like trying to drink from a fire hose! One step at a time I guess.


Some issues with version 4 include - stall speed is to high (68 kts, goal is approximately 60 kts), wing taper ratio is a little low (.442) per Raymer, pg 25, the elevator placement is likely a problem for spin recovery and the cabin height (approximately 40 inches) is a little to small for me. I think I messed up on the model scaling when I exported and imported between two different software apps (Rhino to Alias).


My initial goals are -
Gross weight: approximately 1700 lbs
Engine: 200 hp
Range: approximately 800 miles
Stall: 60 kts
Cruise: 200 kts
Ceiling: 20,000 ft.
Pilot: 6' 3" and 225 lbs


More to follow as I make a more detailed pass through Simplified Aircraft Design.
 

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Pops

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An airplane like this couldn't have been built in the 70's. The new editor of Kit Airplanes said a couple years ago the homebuilts built before the RV's were of low craftsmanship.

Love at first sight for me.
Dan
 

BJC

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An airplane like this couldn't have been built in the 70's. The new editor of Kit Airplanes said a couple years ago the homebuilts built before the RV's were of low craftsmanship.
Dan
A**holes and opinions are important to the owner, but not so much to anyone else. That editor's opinions were rediculous and demonstrated a great deal of ignorance. That is my opinion, and I'm sticking to it.


BJC
 

mike_t_12

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Mar 7, 2010
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50
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Los Angeles, Ca
Yeah, same for me - love at first sight.
I know Dennis Polen and Darryl Usher had their reasons for not offering a kit or plans. If they had, I think they would have sold quite a few.
Mike
 

BoKu

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The new editor of Kit Airplanes said a couple years ago the homebuilts built before the RV's were of low craftsmanship...
That's kind of an extraordinary claim. Citation?

Thanks, Bob K.
 

mcrae0104

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BJC
The new editor of Kit Airplanes said a couple years ago the homebuilts built before the RV's were of low craftsmanship.
Do you mean Kitplanes magazine? Are you referring to Paul Dye?
 
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