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Author Topic: Starting my Mustunt IV  (Read 2965 times)

Offline Pacific Sun

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Starting my Mustunt IV
« on: January 13, 2023, 10:22:39 AM »
Dear friends,
first of all, sorry if my English is not as good as I would like it to be.
I have decided to build a Mustunt IV, I am just starting and I am in the phase of preparing templates, profiles, materials, etc.
I am transferring all the parts from the plan to DXF files to be able to laser cut the parts and by the way have the plan digitized, I think it is more operative and I like to have my plans like this. (See Picture 1)
Well, so far no problem, just a little work with the PC and correcting small errors of measures that do not match in the plan, etc.. I think nothing serious (or not?).
But I have found a small obstacle that really has me blocked and I don't know how to move forward.
When I was going to define the templates to make the ribs, I realized a surprising thing: the profile of the root rib is not symmetrical and that of the marginal rib is symmetrical (see Picture 2). Of course, this generates several issues:
a) It also makes the profiles different. (See Picture 2)
b) Is it a drawing error or this plane really has such this kind of airfoil (asymmetrical in the root and symmetrical in the marginal, and also in one part it is widening)? See the lower lines of the airfoils in Picture 2.
c) After giving a lot of thought to the matter, it turns out that if we make the root rib symmetrical and reduce it in the X axis to 80% and in the Y axis to 75%, the result is that we obtain the almost exact marginal rib. (See Picture 3)
All this leads me to the conclusion that perhaps some deformation must have occurred at some point in the treatment of the original image of the plane, unless of course the original design included these strange profiles, which I do not believe. I am almost 99% sure that this is the way I will follow: make the root rib symmetrical and from there take out all the ribs; applying the percentages of reduction and distance between ribs is not complicated in this case. Another option would be to make the marginal profile asymmetrical, it is not difficult either, dividing each rib in upper and lower part. What is clear to me is that I really don't know how to go about making all the ribs using two different profiles and also one symmetrical and one asymmetrical.

What do you think?

On the other hand, a doubt, in a wing with dihedral the ribs must be vertical or at 90º with respect to the spar? (See Picture 4). I think the right way is to place the ribs 90º respect the spar (drawing below).

Thank you very much for your comments and help. I promise lots of pictures

Greetings to all



Offline dave siegler

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Re: Starting my Mustunt IV
« Reply #1 on: January 13, 2023, 10:43:15 AM »
looks great!

you may want to add breakouts on parts so they do not fall out often sheet when the cut is complete. 

I think the error oou see is a drawing mistake, copying or scanning.   I am pretty sure the designer flipped his template over to make the bottom 1/2 of the wing ribs.
I see many mistakes when moving from paper plans to more accurate CAD drawings. 

it is very likely that the plans were traced from some templates, not templates made from the plan tracings.  So some error may creep in. 
I would mittor the rips at the centerline and move on. 

3 questions
1) what package are you drawing in? 
2) How did you digitize the parts?  pull in a scan and manually trace over it?
3) How many hours do yo expect to spend on the CAD model?
Dave Siegler
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Offline John Carrodus

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Re: Starting my Mustunt IV
« Reply #2 on: January 13, 2023, 11:08:38 AM »
Hi Pacific Sun. I believe Dave is onto it. In my experience during the normal process of reproducing an original, differences and minute mistakes creep in almost unnoticed. Your exacting process has picked it up early on. Well done. The difference is certainly significant enough to throw a curve ball in flight characteristics. Well done.

Online Ken Culbertson

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Re: Starting my Mustunt IV
« Reply #3 on: January 13, 2023, 12:42:08 PM »
Just a caution but if I remember correctly Al used some slightly asymmetrical airfoils on some of his planes.  I can't remember if the Mustunt was one of them, that was nearly 50 years ago!.

Ken
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Online Steve Berry

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Re: Starting my Mustunt IV
« Reply #4 on: January 13, 2023, 02:02:11 PM »
If I remember correctly, Walter Umland has the CAD files for the Mustunt series. You may want to call or email him, see if you can get a copy of them.

As for the airfoil, the Mustunt series is symmetrical, so you are on the right track.

For the positioning of the ribs, they should be placed 90° to the building surface, not the spar. It has to do with how Al would build (wing on rods in a custom jig) and the positioning of the each rib to achieve the proper dihedral. That is why the holes in the ribs shift from near the bottom of the rib at the tip, to near the top at the root. I hope this makes sense.

My best suggestion would be to watch some of Al's videos to get a good understand of how he built his planes. There is a method to the madness. Try this link: https://youtube.com/playlist?list=PLye30M7PuOvgdQksVcIA4wtvBXTGz2DEo. If that doesn't work, I can link them individually.

Steve

Edit: There's also his books that he wrote that covers construction of most of his designs: https://youtube.com/playlist?list=PLkHUtj971Jgk_k-N5vVQX_as0dcVexiz4

Offline Air Ministry .

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Re: Starting my Mustunt IV
« Reply #5 on: January 13, 2023, 04:01:46 PM »
https://outerzone.co.uk/plan_details.asp?ID=10945



Id Assume its DISTORTION . I was  having a fit about a plan being useless . a A3 photocopy from a magazine plan .
Tuns out it had one inch stretch to the root rib , from side profile to plan view . The MAGAZINE DIDNT .

Photocopies tend to distort the stuff around the edge .

========================================================================

All the TEXT is here , https://outerzone.co.uk/plan_details.asp?ID=6443 I think He'd mention it , if He'd utilised asymetric airfoils .

=================================================================================

Owever ! He DOES get into assymetric root ribs , on the Sea Fury . progressing  thru to symetric at the diheadral break .
You get weird airflow effects with low wing / bottom of fuse wing layouts .

Heres some stuff , https://stunthanger.com/smf/open-forum/is-this-the-father-of-modern-stunt-ships/ if you want a headache .

https://stunthanger.com/smf/open-forum/plans-for-mustunt-ii-and-mustunt-iii/

==================================================================================

Here the ROOT RIB is assymetric , progressing to symetric at the thicker 5th rib out , outer panels symetric section .



He figured the lower hourglass corner was where it was at , as far as not bouncing the wheels , figured this'd stop that .

------------------------------------------------------------------------------------------------------------------------------------------------------
Heres what you get if you droop the leading edge on a P 51 , seems to work well . rears constant symetric taper right thru .



Hurricane , I did the opposite . On the FLAT center section , symetric Fwd. T.E. contiues diheadral droop , so Clarke Y ish at fuse . works V Good .

Offline Air Ministry .

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Re: Starting my Mustunt IV
« Reply #6 on: January 13, 2023, 04:18:36 PM »
Might pay to read the whole caboodle . American aircraft Modelor .
https://aerofred.com/details.php?image_id=92680&mode=search&sessionid=frl44pb80q4qsjjlu56fiabjq0





RIGHT . Feb 1973 , HERE .***************************    https://rcbookcase.com/categories.php?publisher_id=46&page=4  *******************************

dunno where FOUR is , maybe YOU could Look For It !  S?P   H^^

===============================================================

just to confuse the issue .  VD~





If you build it within 3 microns of the plans , you should be right . Or you could ' loosen up ' a bit , and get Artistic .



with the paint anyway . But keep it LIGHT , please .

Online Steve Berry

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Re: Starting my Mustunt IV
« Reply #7 on: January 13, 2023, 06:10:43 PM »


dunno where FOUR is , maybe YOU could Look For It !  S?P   H^^

Before a smarta$$ comment, please note that the Mustunt IV was primarily developed and documented on Stuka Stunt, which no longer exists, not here.

Steve

Sent from my SM-N986U using Tapatalk


Online Brett Buck

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Re: Starting my Mustunt IV
« Reply #8 on: January 13, 2023, 08:12:17 PM »

Before a smarta$$ comment, please note that the Mustunt IV was primarily developed and documented on Stuka Stunt, which no longer exists, not here.

    Exactly correct, in the 2010ish time frame, Al updated the Mustunt 3 with a few modern improvements (more tail volume), to get the Mustunt 4,  extensively documented on SSW.

     Brett

Offline Pacific Sun

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Re: Starting my Mustunt IV
« Reply #9 on: January 14, 2023, 12:04:03 PM »
3 questions
1) what package are you drawing in? 
2) How did you digitize the parts?  pull in a scan and manually trace over it?
3) How many hours do yo expect to spend on the CAD model?

Hi, Dave, thank uou very much for your comment.

1) LibreCAD. For me it is the best cad software, really 100% free, a lot of tutos at web, simple, very powerful and consumes few pc resources. Surely for very high level of engineering it will be insufficient, and the aesthetic aspect is not so great, but to make my plans it is perfect. Above all because it allows to work very well the curves. Download at https://librecad.org.
Of course, if you use it and you have doubts or problems do not hesitate to consult me.
Of course, the first thing to do is to check the size of the plan when we have transformed it to DXF and redo the scale. That is easy, we measure in the paper drawing a measure and check how much it measures in the PC. The difference will be re-scale to make both measures (tool Scale, Libre CAD)
Logically, later when we are tracing the pieces we must change the measures to fit well. In my case I use mm , I must change the measures for the materials that I can find. Ex: balsa 1/4 in (6.35 mm)--> I use balsa 6 mm
2) This depends on the origin of the pdf; unfortunately you usually don't know until you test it. If the file can be transformed directly from PDF to DXF (i.e. from a vector source PDF) the ideal convert software is www.hipdf.com (for a vector source PDF). If it is a PDF from bitmap or image source PDF, then what I do is convert PDF to PNG and PNG to DXF. he result is not perfect (if the pdf has a vectorial origin then the result is very good) but it is very acceptable. The work of tracing each part at the beginning is a bit laborious (I draw each part in a higher layer than the drawing and I rely a lot on the constraint tools) depends on your skill with LibreCAD, but with some practice and using well the drawing constraints and the layers the results are amazing and fast. See Pic 5
3) I hope much less than seems necessary. Anyway, the Earth was created in 6 days and I think it will take me a little longer  ;D ;D

Greetings,
Pacific Sun
« Last Edit: January 14, 2023, 01:08:58 PM by Pacific Sun »

Offline Pacific Sun

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Re: Starting my Mustunt IV
« Reply #10 on: January 14, 2023, 12:06:46 PM »
Hi, friends,
First of all thank you all for your comments and help.

Greetings all
Pacific Sun

Offline Pacific Sun

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Re: Starting my Mustunt IV
« Reply #11 on: January 14, 2023, 12:39:14 PM »
---------
Id Assume its DISTORTION . I was  having a fit about a plan being useless . a A3 photocopy from a magazine plan .
Tuns out it had one inch stretch to the root rib , from side profile to plan view . The MAGAZINE DIDNT .

Photocopies tend to distort the stuff around the edge .

========================================================================

All the TEXT is here , https://outerzone.co.uk/plan_details.asp?ID=6443 I think He'd mention it , if He'd utilised asymetric airfoils .

=================================================================================

Owever ! He DOES get into assymetric root ribs , on the Sea Fury . progressing  thru to symetric at the diheadral break .
You get weird airflow effects with low wing / bottom of fuse wing layouts .

Heres some stuff , https://stunthanger.com/smf/open-forum/is-this-the-father-of-modern-stunt-ships/ if you want a headache .

https://stunthanger.com/smf/open-forum/plans-for-mustunt-ii-and-mustunt-iii/

==================================================================================

Here the ROOT RIB is assymetric , progressing to symetric at the thicker 5th rib out , outer panels symetric section .



He figured the lower hourglass corner was where it was at , as far as not bouncing the wheels , figured this'd stop that .

------------------------------------------------------------------------------------------------------------------------------------------------------
Heres what you get if you droop the leading edge on a P 51 , seems to work well . rears constant symetric taper right thru .

Hurricane , I did the opposite . On the FLAT center section , symetric Fwd. T.E. contiues diheadral droop , so Clarke Y ish at fuse . works V Good .

Hi, Air Ministry. Thank you very much for your complete comment.
Unfortunately, I do not understand it very well. In parts:
1.- It is clear that it is always necessary to count with a small deformation if we do not work directly with DXF files. logically the deformation will be bigger the worse is the source image or the treatment of it. For that reason I always check the measures, scaling of the plane, etc.
I understand that you are referring to the Mustunt I, II and III article. I want to build Mustunt IV, which I think is quite different. There is no mention of asymmetric profiles or at least I understood it that way.
3.- I'm sorry, I don't understand very well what you say about the Sea Fury. I seem to remember that the central part of the wing of the Sea Fury does not have a dihedral and the outer part does, so I understand that the central part can be asymmetrical and the outer part symmetrical, is this the right thing to say?
On the other hand, I read it and I do not understand the posts you quote
4.- what do you mean, that the wing profile of the mustunt IV is asymmetrical or do you mean the Sea Fury?
5.- I'm sorry, I don't understand the comment of the P51 quote.

In short, so what do I do ? what is your advice ? symmetrical root to marginal profile for the Mustunt IV ? Please, simple explanations as my technical English is not very good.

Thank you very much for your comments and help.

Greetings,
Pacific Sun

Offline Pacific Sun

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Re: Starting my Mustunt IV
« Reply #12 on: January 14, 2023, 12:51:08 PM »
As for the airfoil, the Mustunt series is symmetrical, so you are on the right track.

For the positioning of the ribs, they should be placed 90° to the building surface, not the spar. It has to do with how Al would build (wing on rods in a custom jig) and the positioning of the each rib to achieve the proper dihedral. That is why the holes in the ribs shift from near the bottom of the rib at the tip, to near the top at the root. I hope this makes sense.

Steve


Hi steve, thank you very much for your comment and suggestions. I will see it.

On the other hand, it is not true that if we put the ribs vertically with respect to the working surface then we will have problems to adjust the inner surface of the marginal to the last rib ?. I think that to be perfectly aligned that face must have fit the degrees of the dihedral, is that correct?
That is the reason why I believe that the ribs should be 90º with respect to the transverse axis of the wing (if dihedral), as in the vast majority of airplanes (models or real). The guide rods are not affected by this, they are just a guide and are always horizontal, but the spars, T.E.and L.E. are not. Please correct me if I am wrong, what do you think?

Greetings,
Pacific Sun

Offline Pacific Sun

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Re: Starting my Mustunt IV
« Reply #13 on: January 14, 2023, 12:57:03 PM »
    Exactly correct, in the 2010ish time frame, Al updated the Mustunt 3 with a few modern improvements (more tail volume), to get the Mustunt 4,  extensively documented on SSW.

     Brett

Hi Brett
Thank you for your comment. What do you mean SSW ? Thanks.
On the other hand, I see a lot of times BBQB about Rabe models. Can you tell me whats means? Thank you very much

Greetings,
Pacific Sun

Online Steve Berry

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Re: Starting my Mustunt IV
« Reply #14 on: January 14, 2023, 01:43:47 PM »
On the other hand, it is not true that if we put the ribs vertically with respect to the working surface then we will have problems to adjust the inner surface of the marginal to the last rib ?. I think that to be perfectly aligned that face must have fit the degrees of the dihedral, is that correct?

You are correct in that the tip (or marginal) rib would need to be adjusted, unless that is accounted for in building the tips. Either way, it's not really going to make a huge difference in the ribs or layout. Remember, we're building a flying model planes, not making a watch.

That is the reason why I believe that the ribs should be 90º with respect to the transverse axis of the wing (if dihedral), as in the vast majority of airplanes (models or real). The guide rods are not affected by this, they are just a guide and are always horizontal, but the spars, T.E.and L.E. are not. Please correct me if I am wrong, what do you think?

I think if you can get the guide rods to line up and keep the wing straight (in respect to possible warps or twists, not dihedral), you're 90% there. The rest is just fiddly details that do matter, but are more of builders preference than anything else. Experts on here can better speak to this than I.

Thank you for your comment. What do you mean SSW ? Thanks.
On the other hand, I see a lot of times BBQB about Rabe models. Can you tell me whats means? Thank you very much

These are easy.

SSW = Stuka Stunt Works, an older forum that most of us used to be on, that unfortunately suffered some hacking/cyber attacks that crashed it, and as a result, it is no longer around. Tons of information, much from guys that are no longer alive, was lost in the crash.

BBQB = Bigger Better Quick Build, in reference to his Bearcat design. Per his videos, it builds quicker and better than his original design.

Steve

Online Brett Buck

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Re: Starting my Mustunt IV
« Reply #15 on: January 14, 2023, 01:47:22 PM »
Hi Brett
Thank you for your comment. What do you mean SSW ? Thanks.
On the other hand, I see a lot of times BBQB about Rabe models. Can you tell me whats means? Thank you very much

      This was the old Stuka Stunt Works forum, run by the reverend Leonard Neumann.  - after RC Online forum disappeared, and before Sparky started Stunthanger. This was more-or-less the source of reference for stunt from 2000 to about 2015. It is now defunct.

   Among many other things, this was where Al Rabe laid out a series of build threads - extremely well-done and engaging, as Al was an absolutely excellent hobby writer and illustrator - about how he would update or demonstrate his design principles.   I actually don't know what BBQB was about, someone else will, I am sure.

     These threads included the Mustunt IV - and update to his classic trainer article as posted by Matt Spencer above. The original article is *very highly recommended*, and although there is a whole lot of things that have been since superceded or made moot, still chock full of good information. More importantly, an outstanding way to begin to understand how to approach stunt design and trimming.

      Brett

Offline Pacific Sun

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Re: Starting my Mustunt IV
« Reply #16 on: January 14, 2023, 03:53:21 PM »
You are correct in that the tip (or marginal) rib would need to be adjusted, unless that is accounted for in building the tips. Either way, it's not really going to make a huge difference in the ribs or layout. Remember, we're building a flying model planes, not making a watch.

Steve

Real like the life  ;D ;D ;D ;D ;D ;D ;D

Pacific Sun

Offline Air Ministry .

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Re: Starting my Mustunt IV
« Reply #17 on: January 14, 2023, 08:41:47 PM »
RIGHT , Things ! ! ! .

MUSTUNT 1,2,3,4 . SAME SERIES - So 1,-2,-3 revevent to 4 ! the fourth being the trickier .

==========================================================

Mustang WING , mine , leading edge droops , see parralel to underside .



This is Al Rabe thought . asymetric , more lift needed in triangle & hourglass LAST Corner . ( If it STALLS the wheels may hit the ground ! )



It Only is between landing gear . OBVIOUSLY More as you get to fuselage .




Offline Air Ministry .

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Re: Starting my Mustunt IV
« Reply #18 on: January 14, 2023, 08:49:45 PM »


timed out yesterday , Will leave the above . The BASIC Sea Fury ( Hawker ) set up is maybe illustrated below . SEE the SPAR .



The basic perogative is ,It will take TWICE AS LONG to BUILD , theres a lot of exactitude necessary . ( Joins & angles and connectors everywhere )
so , If your stuck for something to do , to fill in endless hours ( instead of T. V.  VD~ 0 ]) dont let me stop you .



If you want to get the hours up , FLYING ,  lazer cut Mustunt IV's , in prolifregate , should be as good a way as any .
« Last Edit: January 15, 2023, 08:59:56 PM by Air Ministry . »

Offline Pacific Sun

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Re: Starting my Mustunt IV
« Reply #19 on: January 15, 2023, 06:12:40 AM »

Ok, Air Ministry

So, what do you mean?
Should I make the Mustunt IV with asymmetric airfoil?
If so, up to which rib? (remember that the wing ends in a symmetrical airfoil at the tip rib)

Or on the contrary, as Steve says (we build model airplanes, not watches, I quite agree sometimes we complicate things too much), and I try not to complicate things and make the wing with a symmetrical airfoil ?

Greetings,
Pacific Sun


Online Brett Buck

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Re: Starting my Mustunt IV
« Reply #20 on: January 15, 2023, 06:24:09 AM »
Ok, Air Ministry

So, what do you mean?
Should I make the Mustunt IV with asymmetric airfoil?
If so, up to which rib? (remember that the wing ends in a symmetrical airfoil at the tip rib)

Or on the contrary, as Steve says (we build model airplanes, not watches, I quite agree sometimes we complicate things too much), and I try not to complicate things and make the wing with a symmetrical airfoil ?

    Build the airplane as shown. Matt (Air Ministry) is stuck on 1972 and some other issue. The asymmetrical airfoil on several of Als airplane was intended for a particular aesthetic reason* that does not apply here - or he would have put that on the plans. I used to talk to Al pretty frequently when he was still here, he may have been wrong sometimes, but he never did anything by accident or for no reason. He designed the airplane, build it as shown, and only if you find something wrong with it, go back and change it and/or build the next one differently.

     Steve is qualitatively correct as well, as far as it goes. We are building things from wood/tissue/paint, not synthetic rubies and spring steel. But, building precisely is absolutely necessary to make any sense of your results. The top modelers are generally *very fussy* about precision because even tiny differences in certain areas can make a big difference in the results. I think I can align things like the wing, tail, get the wing straight, to maybe .015". Even then, it moves with the environment and with stress far more than that, and none of the airplanes, even nominally identical, fly exactly the same.  Some areas are very much like watchmaking, particularly control system design/construction, to the point I am using the same principles as a watch wheel pivot (Swiss, apparently, for "bearing") for my bellcrank mount.

     So, you are on the right track. Everyone will chime in with their ideas, pay attention or not. "Thread drift" might be a bit annoying at times, but is a very useful feature in many cases, opening up ideas that the original poster never considered or was even aware of. A strictly Q&A format would not be much use for long, Stunthangar and its predecessors back to 1991 or so would not be able to survive on that format.
 
     Brett

*You can see it in Matts pictures - the asymmetric airfoil makes the Mustang stunt plane look more like a real full-scale Mustang, by avoiding what would otherwise be a big fat belly. The reasoning is that he wanted it to look a certain way, and while you might have difference in the inside/outside turn response, they are are more insides than outsides, and the rest of the airplane is *also* asymmetrical (tail well above the wing, this one has dihedral, the wheels are permanently extended and far below the airplane, etc) so what does a very minor asymmetrical airfoil hurt. It's still plenty of lift in either direction.

Online Ken Culbertson

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Re: Starting my Mustunt IV
« Reply #21 on: January 15, 2023, 09:23:47 AM »
Let me reinforce Brett's statement.  Al did not do anything without a plan or by accident.  If the design has an asymmetrical airfoil, build it that way.  He may have used it for cosmetic reasons but there will most likely have been other changes to balance it, things that we may take for granted today like stab incidence or horn angle to give a differential handle rate of turn.   I commend Brett for getting to know Al at the level needed to "debate" with him.  To us he was that professor that everybody hated, the one that taught you most of what you remember.   Build it his way.  I never saw the IV fly, it was after my time with him, but the others were benchmark "state of the art".

Ken
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Offline Air Ministry .

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Re: Starting my Mustunt IV
« Reply #22 on: January 15, 2023, 08:45:20 PM »
Yep ; ( other Blokes )

Id just ILLUSTRATED assymetric airfoils , as youd MENTIONED THEM ,

this is known as divergance ! Totally Unessesary . But a early Al Plane can stall in a Hourglass Corner -
When the Hourglass ends in a landing , It Leaves a Impression !

The Typhoon Picture is akin to the Sea Fury . From the 5th rib out , which is symetrical - at the ' Diheadral break ' ,
they get progressively thicker , on top , to the root rib . ( also underneath - if its DEAD FLAT it will look concave -
so 1/16th thicker at root alays this visual concavity . ) Assymetrys good on semi scale low wing stuff .



the general ' KEEP IT SIMPLE & add lightness , in general , is the best course .

If you like your hair standing on end , can run quickly , and like large jolts , you can try ' outside the normal ' .
Parently normal people find these disturbing . Personally Id rather the neighbour DID have a 440 dodge ,
or a 426 .  VD~

=============================================================================

We assume your doing the mustunt 4 as a ' ADVANCED TRAINER ' . The Simpler & more dependable it is , the better youll get along with things ,  H^^

Online Brett Buck

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Re: Starting my Mustunt IV
« Reply #23 on: January 15, 2023, 10:16:18 PM »
  I commend Brett for getting to know Al at the level needed to "debate" with him.  To us he was that professor that everybody hated, the one that taught you most of what you remember.   

 Emphasis added.

    Al and I spent an amazing amount of time arguing over various things, and while I will refrain from going into detail (since Al isn't here to dispute or confirm it, or defend himself) I wouldn't have traded the experience for anything.   I am not quite sure how I managed to get on his "respect" list, aside from my willingness to challenge him when he went too far. He crossed the line with me and some of my friends a few times, and I was willing to call him on it, but that seemed to impress him on some level. 

    I am sure he could have been a pretty intimidating person to be around if someone wasn't already pretty secure. There is no denying that as of the late 70's, may have been at the head of the class as far as practical knowledge of design, trim, and flying stunt, certainly at the top of the event. He had a bit more trouble accepting that *other people* also knew things and had learned a lot since he stopped flying, in fact, he was out of it completely during the most revolutionary changes since Bob Palmer.

   Still, for whatever reason, Al and I could talk productively on the phone for hours, he would get mad, I would get mad, but ultimately, we were back on the phone a few weeks later

    Al had a tremendous influence on me, just from reading his articles, second only to his nemesis and my mentor/big brother Ted Fancher. Al was an utterly unique guy, and we are all much better off for him having been here.

     Brett

Online Steve Berry

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Re: Starting my Mustunt IV
« Reply #24 on: January 16, 2023, 04:53:45 PM »
One thing I would definitely recommend is use something along the lines of SeeTemp to make part templates for the formers, fuselage sides, tail surfaces, etc. Include a centerline reference on them for alignment.

A trick from Windy that I learned, and I'm sure it's been around forever by multiple people, is on symmetrical parts, make your template of just half the shape with the centerline. Trace out 1 half, flip it over aligning the centerline, and trace the other half.

Steve

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Offline Air Ministry .

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Re: Starting my Mustunt IV
« Reply #25 on: January 16, 2023, 07:13:14 PM »





https://www.ebay.com/itm/155110324267  Click on the picture & it will become larger , there .

Offline Air Ministry .

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Re: Starting my Mustunt IV
« Reply #26 on: January 16, 2023, 07:16:30 PM »
Look for a Al Rabe SHARK MOUTH ( to bite Er . . . s Butt  ) And WHAT do you FIND . mayaswellputemon .







perloined https://stunthanger.com/smf/open-forum/al-rabe's-flew-that-musteee'stunter-of-his-the-other-day!/msg76912/#msg76912

Offline Air Ministry .

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Re: Starting my Mustunt IV
« Reply #27 on: January 16, 2023, 07:31:04 PM »
SEEING someone brought the Chaps Name Up ,







Those Were the Days ! .  ;D    S?P  S?P  Now , some of us may well regard THIS as Degressing , But you can see his train of thought , here .

















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Re: Starting my Mustunt IV
« Reply #28 on: January 23, 2023, 11:38:34 AM »
Hello to all,
Well, with some accessory lines and except for the final details here are the Mustunt IV ribs (asymmetrical, of course). I'm happy with the work, I've done the best I know and I could.
Thank you all for your comments and help.
I continue with the Mustunt IV (I'm really in love with this plane,  y1 #^ y1 #^).

Greetings,
Pacific Sun

Offline Air Ministry .

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Re: Starting my Mustunt IV
« Reply #29 on: January 24, 2023, 05:49:00 PM »
Very Good , will your machine draw them with the leading edge as the ' base datum ' too . I try it ( in ink ) if Im configuring a airfoil , just for the heck of it .

More ways you look at it , the better you see ?




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Re: Starting my Mustunt IV
« Reply #30 on: January 27, 2023, 11:54:19 AM »
Hello everybody,
So here are the Mustunt IV ribs revised, adjusted and finished. Maybe you can modify some of the leadout holes, but that's a small thing.
Now all that's left is for a buddy of mine to finally buy the laser cutter,  ;D ;D ;D ;D
In the meantime I continue with the formers and the rest of the parts, much easier than the profiles.

Regards
« Last Edit: May 08, 2023, 09:23:31 AM by Pacific Sun »

Offline Pacific Sun

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Re: Starting my Mustunt IV
« Reply #31 on: May 08, 2023, 09:21:44 AM »
Hi everybody,
After diverse troubles, I´m very proud to show you my job. So, now we are ready to beguin laser cut job. Meantime, I ´m drawing CAD the other pieces (formers, stab, etc). This business runs ...

Greetings,
Pacific Blue

Online Steve Berry

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Re: Starting my Mustunt IV
« Reply #32 on: May 08, 2023, 10:39:10 AM »
As a CAD & 3D modeling guy (oil & gas field equipment, as well as our planes), I gotta say....nicely done!

Steve

Online Brett Buck

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Re: Starting my Mustunt IV
« Reply #33 on: May 08, 2023, 11:57:36 AM »
Hi everybody,
After diverse troubles, I´m very proud to show you my job. So, now we are ready to beguin laser cut job. Meantime, I ´m drawing CAD the other pieces (formers, stab, etc). This business runs ...

Greetings,
Pacific Blue

  That's really good, well done! Al would be delighted.

    Brett

Offline Scott Richlen

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Re: Starting my Mustunt IV
« Reply #34 on: May 10, 2023, 02:45:55 PM »
A pretty funny story about Al:

A flying buddy of mine, let's call his name "John", really wanted to build an Al Rabe Mustang.  So he called Al up to order a set of plans.  But the phone conversation turned into an interview.  Al started asking all kinds of questions   - he was interviewing my friend "John" to see if he was "qualified" to build the Mustang.  At the end of the conversation he told "John" that he wasn't going to sell him a set of the plans because he was unqualified to build his P-51.   :-[  "John" told me all about his "interview" right after it happened.  It was actually pretty funny!   :D

The story does have a happy ending: about three months after that, I got a call from "John" telling me that Al sent him a set P-51 plans!  I guess Al changed his mind.  "John" then proceeded to build the P-51 (or at least the major parts of it - the wing and the fuselage.)  He did a really nice job! 

However, I guess this story actually does have an unhappy ending because "John" then got tired of it for whatever reason and decided he wouldn't assemble and finish it.   :P

True story.

Actually, the unhappiest part is that "John" brought the parts over to me and asked if I couldn't store them while he was moving.  And now he doesn't want them back!  (I've still got the wing hanging in my basement.)   :-\
« Last Edit: May 10, 2023, 03:08:17 PM by Scott Richlen »

Online Ken Culbertson

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Re: Starting my Mustunt IV
« Reply #35 on: May 10, 2023, 06:29:52 PM »
A pretty funny story about Al:

A flying buddy of mine, let's call his name "John", really wanted to build an Al Rabe Mustang.  So he called Al up to order a set of plans.  But the phone conversation turned into an interview.  Al started asking all kinds of questions   - he was interviewing my friend "John" to see if he was "qualified" to build the Mustang.  At the end of the conversation he told "John" that he wasn't going to sell him a set of the plans because he was unqualified to build his P-51.   :-[  "John" told me all about his "interview" right after it happened.  It was actually pretty funny!   :D

The story does have a happy ending: about three months after that, I got a call from "John" telling me that Al sent him a set P-51 plans!  I guess Al changed his mind.  "John" then proceeded to build the P-51 (or at least the major parts of it - the wing and the fuselage.)  He did a really nice job! 

However, I guess this story actually does have an unhappy ending because "John" then got tired of it for whatever reason and decided he wouldn't assemble and finish it.   :P

True story.

Actually, the unhappiest part is that "John" brought the parts over to me and asked if I couldn't store them while he was moving.  And now he doesn't want them back!  (I've still got the wing hanging in my basement.)   :-\
That sounds like Al.  He was one of a kind.

Ken
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC


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