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-   -   Southern R/C bootlegger plan (https://www.rcuniverse.com/forum/classic-rc-pattern-flying-379/11117712-southern-r-c-bootlegger-plan.html)

dphill2 01-10-2013 02:05 PM

RE: Southern R/C bootlegger plan
 


doxilia 01-10-2013 02:32 PM

RE: Southern R/C bootlegger plan
 
Dave,

Understood. That approach certainly works better with a glass fuse than a wood one. A top flat wood fuse would make it easier to build and use as a construction base - much like an Arrow.

Rather than angling the entire floor upward as you did, I wonder if it might be better to simply use a flat top all the way and increase the height of the FW. I suppose this would require a fuse top header rather than an angled straight header. But I'm thinking aloud now.

12 oz sounds pretty good for the glass! I guess there is no fin. My heavier (one of two) GP Tipo 720 fuse was 20 oz.

David

dphill2 01-10-2013 02:48 PM

RE: Southern R/C bootlegger plan
 


doxilia 01-10-2013 05:36 PM

RE: Southern R/C bootlegger plan
 
Dave,

The idea I have is not so much to raise the FW but to make it taller - but only on the sides about 3/8" thick on each side at the horizontal pipe level. The FW would have an arc cut out of it in the center top and the lite ply floor would have a matching arc in the horizontal plane. I would then produce a FG "cup" to bridge the two, provide the space for the FT header to pass up into the pipe compartment and close off the tank area.

It might be a lot of trouble but it's basically how one does it on a Deception that has a slab flat fuse top. I prefer the angled header floor but from a construction standpoint, it's a little messier because the entire floor needs to be captured by the sides; it can't be used on top to form a floor from side to side atop the fuse sides (again, like the Deception). One has to be a lot more precise in cutting that captured lite ply floor as the fuse is airfoiled in top view. Of course a laser can do this but by hand one would have to be very accurate in order not to warp the fuse or wind up with nasty little gaps between the floor and sides.

In a glass fuse this is less of an issue as the fuse is pretty much an exoskeleton and wood inside can be less than perfect. Epoxy and MB can close any unwanted gaps. In wood, I'm not so fond of that. Imagine what Ralph would say!! :D He'd be cringing over his computer and we can't have that!

But... I did it with the MK Chipmunk so no reason not to here as well...

The other thing is who on earth makes 7-10 degree RE headers!? No one, we'd need it custom made or bend a straight one. With the right tools...

Further thought: the header that comes with OPS Supers (gold head) might be just perfect. I believe it's a 0.5" fuse top or so. I need to print the plans to check how it might fit. OS RF headers and old Rossi headers might also fit the bill.

David

dphill2 01-10-2013 06:22 PM

RE: Southern R/C bootlegger plan
 


doxilia 01-10-2013 06:40 PM

RE: Southern R/C bootlegger plan
 

ORIGINAL: dphill2

David ,
I'm sure that you will work it out and you are on the right track, I think the wood airplane will be a lot of fun to build and even be EZer when you put in the pipe floor. I don't know where I saw it, but somebody said the sides of the Bootlegger are curved !! Not true, the one I have is flat as a wood built airplane, and has no curve in the fuse side at all !!!! I also have a Tiger Tail III from Southern RC and it has an all most round shape to it ... just for your info..
Dave,

thanks, I will sort it out. Really a captured fuse top just needs to track the inside of the fuse sides so one can use that to produce it. Once I put an angle (up or down) into it though, you wind up with "width" issues as you decend into the fuse. I think the flat top will work out and it will be easy as it will mate nicely to the glass top deck made by Julio.

When you say someone said the sides of the Boot are curved, do you mean in top view (airfoiled from front to back) or in front view (arced from top to bottom). I haven't checked the width issue yet but Bryan has. It looks fairly clear that the fuse is airfoiled but otherwise it's a box in section with curved corners - like a well rounded Kaos - true? This is what the deck and blue fuse seems to indicate: flat top-half round-flat side-half round-flat bottom (from side to side).

In other words, the Boot is a rounded rectangle in section while the TTIII is more of an oval in section - make sense?


As for the header I used a OS FSR in the last rear ex airplane and needed a 5-7deg header . I took a mac header for my OS and shaved the mount face to the angle I needed, bolted it on the motor and it worked great !!

Dave...
Would that be an OS VF? The FSR were side exhaust. Excellent idea on the header shave! I'll have to try that probably on an Exception build. I wonder if one can "sand" aluminum. I guess a lathe would make small work of this but what about some Dremel tip of sorts?

Have you begun a wood Boot build?

David

doxilia 01-10-2013 08:31 PM

RE: Southern R/C bootlegger plan
 
Julio,

I was sorting out the wing core templates. What thickness of sheeting do you want to use to skin them?

I currently have them with 1/32" sheeting as that is becoming my new standard. If you want to use 1/16", let me know and I'll adjust them accordingly.

David

dphill2 01-10-2013 09:09 PM

RE: Southern R/C bootlegger plan
 


Roguedog 01-11-2013 12:01 AM

RE: Southern R/C bootlegger plan
 


/</p>

Roguedog 01-11-2013 12:24 AM

RE: Southern R/C bootlegger plan
 
edit - double post Clicked quote then ok instead of edit for the last post.

kitfox1 01-11-2013 05:42 AM

RE: Southern R/C bootlegger plan
 
doxilia,
I. Normally I use 1/16, but send the 1/32 and I will try it. I have Compufoil and if you are using the same software to make the wing core files it will be easy for me to change the thickness to 1/16. Thank you for the help. Julio

dwaynenancy 01-11-2013 06:53 AM

RE: Southern R/C bootlegger plan
 
I've got three Boots that I have had since 1980. Two have been flown while the other has never had its equipment installed. Set up for OPS and Kraft retracts. One has a Rossi installed. All three were Southern RC kits and all were built by the late Jim Simpson.

doxilia 01-11-2013 07:08 AM

RE: Southern R/C bootlegger plan
 
Julio,

OK Cool. I'll take a look at it again this evening.

I've also started to draw core airfoil templates with wrap-around LE's. The idea is that if the core is CNC cut, one can produce perfect LE's by cutting them into the foam and using a ~3-4" slice of sheeting to wrap the LE. Naturally, one has to mold the balsa before it can be bonded on to the core's LE. The remainder of the core is sheeted after this first application of the LE sheeting and they can be sheeted back to the wing TE of the feather cut core to include foam ailerons. I like to cap the TE with 1/8" or 3/32" square HW (sanded to airfoil if needed) or, laminate a thin CF strip between the top and bottom sheet to produce a hard dent resistant TE.

Benefits of the wrap around core are a perfect foil entry to the wing, no LE balsa carving and sanding and resulting potential asymmetries between left/right panels. They also build faster (or so I'm told - I haven't done one yet). One caveat, this approach works on wings but not so well on tail feathers due to their smaller size, thinner foil and more pronounced LE curvature. If one doesn't like this approach or a problem arises when sheeting the foam LE, top and bottom can be sheeted in the normal way without worrying about the LE and then the LE can be block sanded back 1/4" to 3/8" and have a normal sheet balsa LE applied and sanded to airfoil.

I should mention something important. Since the object of the thread is to produce a wood fuse Boot with glass deck (I think), I scaled my plan to produce a wing span of exactly 64" per spec. This entailed an enlargement of ~3% over the Southern plan. According to Paul's post further up, the plan, as he originally supplied it, matches the glass and foam Southern kit to a T which means that the plan (and Southern kit) is ever so slightly "under spec". Looked at another way, that the specs posted are not accurate. Either way, the Boot plan I'm working off of is 64" in span and 58.85" in length (spinner tip to rudder bottom TE). The wing area computes to 726 squares rather than 720 (spec). This slight enlargement has no effect on mating a wing cut from it to a glass fuse or for that matter mating Julio's glass deck to it. The width of the model and top view profile would ideally be designed to match Julio's deck but Bryan has done a great job of inferring the fuse top shape from the existing plan for a complete wood fuse (i.e., no glass deck).

I'm not using Compufoil but if you tell me what type of file you can import into the software, I can try and output that.

David

PS Bryan, if you have the wing airfoils, by all means. I'm not trying to cut into the thread, just wanted to contribute if I can as I'm interested in this design.

doxilia 01-11-2013 07:22 AM

RE: Southern R/C bootlegger plan
 


ORIGINAL: Roguedog

I'm glad Dave clarified what he was talking I couldn't imagine what his BL fuse looked like.

It's inevitable that when building balsa sided fuse, using flat 4'' x 3/16'' balsa sheet, or whatever, that your going to end up with a curved airfoiled shape. You would think an airfoiled fuse shape would help during a knife edge maneuver.

All are different widths and will produce an airfoiled or curved fuse when bending flat sheet around them and hopefully will be as flat as Dave's ruler clearly shows.
Bryan,

I don't think there is any "curvature" issue. Dave was just pointing out that the sides are flat top to bottom not fore and aft. The cross-section is one of a rounded rectangle (as you have drawn) rather than an oval (e.g., an Aurora). That's what I asked him to clarify in the recent posts. Naturally, the shape of the fuse in cross-section is dictated by the former shape and wood construction about them.

The overall airfoil shape to the fuselage from front to back is another matter and, as you say, desirable in many cases. One of the designs I find unusual in this respect is the Arrow as it doesn't have an airfoiled shape (if any, it's minimal) in top view. It is basically a box up to the wing TE and then the sides come together angled in toward the rudder hinge line. But I digress. In short, I see no problem with your fuse top drawing or shape - it ought to be pretty faithful to the Southern glass fuse.


David Oxilia
If you look at the second former from the left this is what I imagined would be a cross section with the glass canopy with height measurement being offered by Julio.
Yup! Thanks, got that.

David

MTK 01-11-2013 08:22 AM

RE: Southern R/C bootlegger plan
 


ORIGINAL: doxilia

Julio,

OK Cool. I'll take a look at it again this evening.

I've also started to draw core airfoil templates with wrap-around LE's. The idea is that if the core is CNC cut, one can produce perfect LE's by cutting them into the foam and using a ~3-4" slice of sheeting to wrap the LE. Naturally, one has to mold the balsa before it can be bonded on to the core's LE. The remainder of the core is sheeted after this first application of the LE sheeting and they can be sheeted back to the wing TE of the feather cut core to include foam ailerons. I like to cap the TE with 1/8" or 3/32" square HW (sanded to airfoil if needed) or, laminate a thin CF strip between the top and bottom sheet to produce a hard dent resistant TE.

Benefits of the wrap around core are a perfect foil entry to the wing, no LE balsa carving and sanding and resulting potential asymmetries between left/right panels. They also build faster (or so I'm told - I haven't done one yet). One caveat, this approach works on wings but not so well on tail feathers due to their smaller size, thinner foil and more pronounced LE curvature. If one doesn't like this approach or a problem arises when sheeting the foam LE, top and bottom can be sheeted in the normal way without worrying about the LE and then the LE can be block sanded back 1/4" to 3/8" and have a normal sheet balsa LE applied and sanded to airfoil.

I should mention something important. Since the object of the thread is to produce a wood fuse Boot with glass deck (I think), I scaled my plan to produce a wing span of exactly 64" per spec. This entailed an enlargement of ~3% over the Southern plan. According to Paul's post further up, the plan, as he originally supplied it, matches the glass and foam Southern kit to a T which means that the plan (and Southern kit) is ever so slightly "under spec". Looked at another way, that the specs posted are not accurate. Either way, the Boot plan I'm working off of is 64" in span and 58.85" in length (spinner tip to rudder bottom TE). The wing area computes to 726 squares rather than 720 (spec). This slight enlargement has no effect on mating a wing cut from it to a glass fuse or for that matter mating Julio's glass deck to it. The width of the model and top view profile would ideally be designed to match Julio's deck but Bryan has done a great job of inferring the fuse top shape from the existing plan for a complete wood fuse (i.e., no glass deck).

I'm not using Compufoil but if you tell me what type of file you can import into the software, I can try and output that.

David

PS Bryan, if you have the wing airfoils, by all means. I'm not trying to cut into the thread, just wanted to contribute if I can as I'm interested in this design.
Dave, just a suggestion,

On tails, you may want to use 1/32" sheeting. This size will conform much easier to themolding fixture.

I use 1/32" for stabs, elevators,rudders, on reasonably large models (55 cc gasoline size). But the finish is medium silkspan which adds consderable strength for minimal weight gain

dphill2 01-11-2013 09:21 AM

RE: Southern R/C bootlegger plan
 


dphill2 01-12-2013 08:57 AM

RE: Southern R/C bootlegger plan
 


doxilia 01-12-2013 09:41 AM

RE: Southern R/C bootlegger plan
 
1 Attachment(s)
Dave,

uncanny!!

The more we look into it, the more we realize that the Bootlegger is a stretched Compensator! Even the name of the "variation" is appropriate for what is now clear to be it's origin. We know Miller designed the Compensator but who is credited for the Boot? I assume not Steve Helms. This story sort of tracks in a similar fashion to the Curare/Tiporare story:

Curare -> Tipo
Compensator -> Boot

and so designs evolve... I also wonder why the Bootlegger, Compensator & Deception all share a very similar, if not identical, airfoil. Did Kimbro share this airfoil with them? I believe his design came before the others if memory serves (~1979?). Maybe Kimbro could share some light on the subject if he happens to check in.

Because of the angle of the photos it's hard to tell whether the stab airfoil matches the airfoil cutout into the fuse side. I'm assuming it does. From the pictures it looks like the Boot is a slightly stretched Compensator with a taller fuse, both above and below.

I worked on the wing/stab plan a little more last night and am almost done. The one thing I'm not sold on is the stab airfoil as it clearly breaks in the hinge line vicinity due to the wide elevator chord. In those days it was typical to build a stab from a foam core and cap it both at the LE and TE with balsa and then sand in an elevator from sheet balsa behind it. Today, I, as many others I suspect, would prefer to build the control surfaces from the feather cut core. This allows the airfoil to be continuous all the way to the aileron/elevator TE.

Because of the above, I have been debating whether the stab should be altered slightly to produce a smooth continuous airfoil from LE stab to elevator TE, particularly given the idea of cutting feather tailed cores. The picture below shows the continuous wing and discontinuous stab airfoils. The stab inflection is per the Southern glass fuse stab. BTW, skins as shown are 1/32".

Thoughts?

David

dphill2 01-12-2013 10:05 AM

RE: Southern R/C bootlegger plan
 


impactiq 01-12-2013 11:23 AM

RE: Southern R/C bootlegger plan
 


ORIGINAL: doxilia

Because of the above, I have been debating whether the stab should be altered slightly to produce a smooth continuous airfoil from LE stab to elevator TE, particularly given the idea of cutting feather tailed cores. The picture below shows the continuous wing and discontinuous stab airfoils. The stab inflection is per the Southern glass fuse stab. BTW, skins as shown are 1/32''.

Thoughts?

David
Dave,

The reason for the stab shape is just like the diamond shape stab. It makes the controls around neutral less sensitive. It was a way to fix a touchy elevator back in the day before radios had EXPO.

Mark

dphill2 01-12-2013 11:33 AM

RE: Southern R/C bootlegger plan
 


doxilia 01-12-2013 12:11 PM

RE: Southern R/C bootlegger plan
 
Mark,

sure, I understand that, but the issue I'm having is not whether it's diamond or slightly more continuous as the Southern plan shows. It's the fact that the Boot stab (probably unlike the Compensator stab due to the flat from the high point back the elevator TE) is inflected. This means that the airfoil changes angle around the hinge line (not the high point) rather than descend uniformly, in a straight line if necessary, to the rear of the elevator. The width of the elevator is such that the angle changes in relation to the curvature of the stab itself.

Would the elevator behavior be substantially different if the stab airfoil were uniform and continuous from the high point in the foil back to the elevator TE? I guess it might be easier to see what I mean if I drew a properly airfoiled stab and put the two side by side... Then again, the Boot flew fine for many years. It's just that sheeting, or even cutting, a core with feathered TE per this design is not very desirable.

Dave,

good stuff. Are you going to scratch one out then? Will you need to move the FW back to put the thrust washer per plan? I believe the RF's are considerably longer than the OPS big reds.

David

Roguedog 01-12-2013 12:12 PM

RE: Southern R/C bootlegger plan
 


/</p>

dphill2 01-12-2013 12:41 PM

RE: Southern R/C bootlegger plan
 


doxilia 01-12-2013 12:42 PM

RE: Southern R/C bootlegger plan
 


ORIGINAL: Roguedog
I noticed that since the BL was using foam cores that the plans showed a taper along the LE and TE's of both the wing and stab. The final version I'll post will be based on the orignal root shapes with the following mod for easier building, the leading and trailing edges will be uniform instead of tapered as in the original plan. Some may not like this but it's a very slight mod from the orginal and does not change the foil much. It will make the build very much faster in that you won't have to shape and sand the crap out of those portions to reproduce the tapered LE and TE on the wing and stab.
Bryan,

I should note that my captured comments regarding airfoil in the above are not related to how you chose to design the LE and TE thickness of the surfaces - that's something all together different. Just want to make sure we're not mixing apples and oranges. As far as using a constant thickness LE and TE along the span of the surfaces (if I understand you correctly), that's obviously a personal choice. I believe this makes a significant difference to how a model flies (particularly LE shape and taper). In my experience, producing span tapered LE's, TE's and ailerons is a non-issue, whether foam core or built-up. The amount of sanding required is minimal (ailerons aside) and I don't even notice whether I'm sanding a constant or variable thickness span; I just use the rib (or core) design to track the sanding. It is of course easier to design a framed up wing with LE and TE that are not captured by sheeting (Japanese classic style) as one then uses the sheeting as a datum to sand the LE and TE to correct taper. Basically the same as one does with a foam core wing.

Still, these are modified Boot's (to different degrees) so we can do anything we like.


Those using foam core wouldn't have the same problem as the taper would be built into the cores. For those that opt for the built up version it will be very simple to glue up and sand to shape as the LE and TE's will be the same dimesion the whole cord of the wing and stab if using the plan I've been working on
When you say the "whole cord", you mean the whole span I assume?

It's great that you are developing a framed up wing and stab as I started to work on foam core plans so the two options may be available. There's not that much to what I'm doing other than producing proper airfoil templates for root and tip. As mentioned in recent posts, I'm pretty much done but I'm not sold on the stab airfoil. An ever so slight modification would bring it inline with the type of continuous airfoil stab that the Deception has. The issue is, to do it or not. I'm hesitant because maybe this inflection is more important than I might think...

As for the fuse, I'm keen on using Julio's glass deck as it not only makes construction much simpler and less work but it also provides for a more heat resistant compartment for the header and pipe. Of course, your built up canopy design is a great option for those who prefer a full wood frame up - a bit like Matt did on his original Arrow (I believe he used a section of thin aluminum for the pipe tunnel itself).

David


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