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Author Topic: stunt plane suggestion for a .15?  (Read 19114 times)

Offline Target

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Re: stunt plane suggestion for a .15?
« Reply #50 on: January 04, 2017, 11:44:20 PM »
Hey Chris!  You are going to share what you build with us, yes?  Whether it flies off the board, or comes off the field on a board?
Yes Tim, I will share what I build.
More and more I'm likely to "go nuts" and do a vacuum bagged foam wing. The only hitch in my giddy-up is I'll have to decide on a wing profile first... I've trolled for suggestions in this thread, but no biters yet. I'd definitely like to keep this design flapless because it will be a lighter, stronger, simpler  and cleaner bagged wing. Doing the internal bellcrank will be trouble enough....who knows,.maybe a top or bottom of the wing would work for the first attempt.
I hate making foam cutting templates, and I also am too almost divorced to buy a cnc cutter... But I'm a pro with a gravity cutter anyway. You'll see that. I'll likely make all the parts vacuum bagged foam, even the fuselage, with some wood reinforcements up forward.
It should be interesting....
And thanks to ALL OF YOU, for the suggestions on which design to build. It's appreciated!
Very Respectfully,
Chris
Regards,
Chris
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Offline Tim Wescott

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Re: stunt plane suggestion for a .15?
« Reply #51 on: January 05, 2017, 09:41:49 AM »
Hey Chris:

I'd taper the wings maybe about 25% (by 25%, not too 25% -- make the tip chord 75% of the root).  For flapless I'd sweep the LE almost not at all, ending up with a sharply swept-forward TE, like a foam combat plane. 

I've got a cartoon-scale Mooney that I built for my wife that mounts the wing on the bottom of the fuselage with the bellcrank on top.  I can't tell the difference from running the leadouts inside, and the building (and repairing) was certainly vastly simplified.  As a bonus, since the leadout guide is external it was dead easy to make it adjustable up and down, which meant that I didn't have to try to guess the vertical CG ahead of time -- I just adjusted for it after the fact.

(And just for chuckles, the plane in question uses Phil Cartier's wing cores and SLC covering, with 1/8 x 3/8" balsa spars.  It's plenty strong enough for anything except the full-on impacts with the ground that it's been experiencing, and it's easy to repair from those.)

Here's a picture of the thing.  It's close to having flown off the board, except for a nasty tendency to go slack on takeoff, which I adjust to so automatically that I then forget and hand the handle to her, then she crashes it in less than half a circle and has words with me.  We both need to get out flying more...

The picture is from this build thread.  If I was going to do what you're planning, I'd just scale this down -- or use the concept, but do a cartoon of some other low-wing airplane, like a Beech Bonanza (straight tail if I'm building for a beginner, or a V if I want to get the locals going again).

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Offline Target

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Re: stunt plane suggestion for a .15?
« Reply #52 on: January 05, 2017, 01:02:41 PM »
Thanks Tim.
So, essentially you're suggesting a forward swept wing planform, vice a straight 1/4 chord or swept back 1/4 chord.
That moves the cg forward at the wing root.
Other than the ability to do this due to the lack of flap hingeline to deal with, what's the reason?
I assume this slightly extends the tail moment the amount of the cg shift, but other than that slight weight and structure freebie, any other reason?
I seem to recall that a swept forward planform is marginally harder to stall, but also like building in anhedral, right? That probably doesn't apply much in control line, I would think (the dihedral effect with sweepback, I mean).
I think it's better to have a buddy teach your wife to fly. I'm not an authority, since I'm no longer married, LOL.
My ex did me a favor though, I have a great new gf that works hard and appreciates me. What a concept!
Thanks for posting the picture.
Vr,
Chris
« Last Edit: January 05, 2017, 05:02:08 PM by Chris Behm »
Regards,
Chris
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Offline Tim Wescott

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Re: stunt plane suggestion for a .15?
« Reply #53 on: January 05, 2017, 01:09:49 PM »
The number one single biggest reason I suggest that planform is because Howard Rush said that it works well for combat, and should work well for flapless stunt (something about having good yaw characteristics in the wind).  In the same thread he was also quick to point out that a swept-forward flap line was Bad News, so if you're using flaps, use the "normal" wing sweep of a typical stunter.

It's what came with the wing cores on that Mooney, and it works well -- it's also more or less what a Flight Streak looks like, and they make good stunters when you set them up right.  So not only do I have Howard's word on it, my personal experience with flapless stunters says that it works good.
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Re: stunt plane suggestion for a .15?
« Reply #54 on: January 06, 2017, 07:19:21 AM »
...I believe my tt is the non ball bearing, "GP" version. Just glanced at it the other day.


If your control line GP is like mine it has a large sprinkler venturi (note the offset needle valve).

George
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Offline Target

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Re: stunt plane suggestion for a .15?
« Reply #55 on: January 07, 2017, 08:20:07 AM »


If your control line GP is like mine it has a large sprinkler venturi (note the offset needle valve).

George
It's an rc-v version with a carb (at least it is for now)
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Chris
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Offline Allan Perret

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Re: stunt plane suggestion for a .15?
« Reply #56 on: January 07, 2017, 09:00:32 AM »
Here it is.   PJ Rowland did a Gieseke Nobler with the Stalker 61 for power.  




Yeah, picked up on this in the other Nobler thread:

http://stunthanger.com/smf/open-forum/new-offering-from-brodak/

And here's a bit of info on his build:

http://stunthanger.com/smf/classic-planes/new-gieseke-nobler-(-now-with-finished-pics-)/

Yesterday I opened the box on the Brodak Cub to have another look.  What prompted this was Keiths info about the wing area and wing span. There are different numbers depending on where you look. The kit box info states 40" span and 297sq/in area.  The plans measure out to around 36 3/4" span or so and a rough calc of 292sq/in. (which does not take into account the area covered by the fuselage).  I'm not sure but I think it was mentioned you might sqeeze a few more sq/in's out of it if you do not trim the LE, TE and spars and simple adjust the rib spacing.  I expect it would not be difficult to simply replace the span-wise runs of wood with longer and add a rib or two and maintain the original space I guess?   When looking at the plans it appears that the 15. will be enough (fits very well in the fuselage, based on the side view).  But I still wonder how the .25 might work if one tweaked the wing area a bit. Hmm very interesting.

Sorry about the thread jacking.


Hey Tony: Opened my Cub kit today and seeing same thing as you, measuring span off the plan I get 37".
Brodak's website and label on box both indicate span 40". 
In the other thread referenced above, John Miller said he got OK from Brodak to increase span to 40, wonder what happened with that ?
So I am planning to increase rib spacing as necessary to get span out to 40".
I will be using B-15 or Enya 15CX for power.  The B-15 w/muff is 1/2oz lighter than Enya w/muff. 
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Offline Target

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Re: stunt plane suggestion for a .15?
« Reply #57 on: January 07, 2017, 04:54:29 PM »
Back to topic, Looks like my TT .15V (RC) is a baffle engine.
See attached pictures.
If the plane that I build needs more power, I could swap this for the engine on my combat wing, a Magnum .15, which seems to have some "nuts".
Regards,
Chris
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Offline Randy Cuberly

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Re: stunt plane suggestion for a .15?
« Reply #58 on: January 07, 2017, 06:23:44 PM »
It is impossible to have an airplane model that just "flies off the board."  There was a finite number of that type of airplane models in the universe and they were all used up by 1952.

(That is why many fly in the Old Time Stunt event.  They are still looking for some remnant of those airplanes.  At least that is a partial explanation of how I understand things.)

Keith

If by "Flies right off the board" means that it needs absolutely no trimming to be competitive I definitely agree.  However a good thorough "Bench trimming session" before taking the thing out to fly it can result in an airplane that is capable of safely stumbling through most of the pattern maneuvers on the first or second flight.  Even I have managed that many times thanks to Jim Hoffman introducing me to Bench trimming sometime in the 1980's.

I certainly do believe any and all competitive stunters are more or less always being trimmed one way or another.  Even some trimming sometimes occurs between two competitive flights in the same day!

I want to make it very clear that by saying this I'm not disagreeing with what Keith said in any way.  I just wanted to clarify things a bit by adding the "Bench Trimming" situation into the mix.  All the expert level fliers I know (including Keith) certainly know that their airplane is going to fly reasonably straight and happy on the first flight.  However short tanking the first flight is never a bad idea "Just in case".   LL~ LL~

There used to be a pretty good thread on bench trimming on this forum but I'm not sure it still exists.  "Stunt News" has also had at least one good article on doing it, Probably more than one!

Randy Cuberly
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Offline paw080

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Re: stunt plane suggestion for a .15?
« Reply #59 on: January 07, 2017, 08:35:19 PM »


Hello Chris Behm, Make things simple for yourself and get an old Top Flite or a repo

kit of the Flite-Streak. Build it as light as you can, trim it effectively and you will

have a perfect profile model that will out fly anything previously mentioned; except

for an FAI Combat ship. What is little known, or remembered,  is that in the early

ads for the FS, George Aldrich himself recommended a .15 be used for a stunt model

trainer.  There were not many .15 engines that were really suitable then, other than a Torp .15, so he may

have been thinking of using a diesel engine such as the Oliver Tiger mkIII or a Webra Mach 1.

 I'm sure your TT .15 has power equal to a strong mid 1950's diesel. 

Barry Baxter flew several Flite Streaks with PAW, Marz and other 1980's .15 diesel engines,

all on 60' X .015" lines.  Come to think of it, I saw the late Dennis Lien fly a FS on 60' lines

using an MVVS Junior(.12 cu") diesel.

If you find a lighter tongue muffler  or fly without that heavy TT version, the finished ready

to fly weight of your Flite Streak should be less than 23.5 ozs.  Good luck;

Tony ;)

Offline Target

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Re: stunt plane suggestion for a .15?
« Reply #60 on: January 07, 2017, 11:10:24 PM »
Thanks for the suggestion Tony.
Vr,
Chris
Regards,
Chris
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Offline wwwarbird

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Re: stunt plane suggestion for a .15?
« Reply #61 on: January 07, 2017, 11:12:55 PM »

Hello Chris Behm, Make things simple for yourself and get an old Top Flite or a repo

kit of the Flite-Streak. Build it as light as you can, trim it effectively and you will

have a perfect profile model that will out fly anything previously mentioned; except

for an FAI Combat ship.

Tony ;)


 Not a terrible idea, but I'm betting 10 bucks that Tony here has never built and/or flown a Challenger .15.  D>K
Narrowly averting disaster since 1964! 

Wayne Willey
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Offline Dane Martin

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Re: stunt plane suggestion for a .15?
« Reply #62 on: January 07, 2017, 11:21:56 PM »
Back to topic, Looks like my TT .15V (RC) is a baffle engine.
See attached pictures.
If the plane that I build needs more power, I could swap this for the engine on my combat wing, a Magnum .15, which seems to have some "nuts".

Planes are planes, you've got many good suggestions here. But on that engine, I wouldn't be worried about power. Yes, it's a baffle piston, but all my enya .15's are baffle piston. And I wouldn't hesitate to put them in any plane these great folks have listed here.

Offline Trostle

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Re: stunt plane suggestion for a .15?
« Reply #63 on: January 08, 2017, 12:45:08 AM »
"It is impossible to have an airplane model that just "flies off the board."  There was a finite number of that type of airplane models in the universe and they were all used up by 1952."

If by "Flies right off the board" means that it needs absolutely no trimming to be competitive I definitely agree. 

(Clip)

Randy Cuberly

I guess my attempt at a bit of humor did not come across that way.  My comment was slanted to the articles published "back in the day", like prior to 1952, where the designers/authors would write that their design "flew right off the board".  Such comments are a bit more rare now, so I was suggesting that maybe there is/was a finite number of airplanes in the universe that could fly "right off the board", they must have been used up "back in the day".  I was going to draw a parallel to the fixed number of models in the universe that can fly off the board to entropy which my limited understanding is also fixed in the universe, but I have a really hard time getting my mind around the concept of entropy and unavailable energy.

Another favorite statement "back in the day" is that their design "can do everything in the book".  Many of those designs, though Old Time Stunt legal, often present a challenge to do even the most rudimentary maneuvers.

I apologize for getting off on this tangent on this thread.

Keith

Offline Target

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Re: stunt plane suggestion for a .15?
« Reply #64 on: January 08, 2017, 02:20:49 AM »
No apology necessary, Keith.
Regards,
Chris
Regards,
Chris
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Offline paw080

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Re: stunt plane suggestion for a .15?
« Reply #65 on: January 10, 2017, 03:08:50 PM »

 Not a terrible idea, but I'm betting 10 bucks that Tony here has never built and/or flown a Challenger .15.  D>K

Welp  wwwar, save your 10 bucks. It's true I haven't built nor flown a Challenger .15; but my observation is

based on the possible specs of the model. So, please help me judge the model by it's actual specs; such as what

the wing area is, and also what is the percentage of the airfoil used. This way I can calculate what the wing loading

would be for a 25 oz model.  If I like the potential wing loading,  I can decide to possibly build a Challenger .15 in the

future.   Thanks in advance for the Challenger .15 specs.

Tony :)

Offline Tim Wescott

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Re: stunt plane suggestion for a .15?
« Reply #66 on: January 10, 2017, 03:30:04 PM »
... like prior to 1952, where the designers/authors would write that their design "flew right off the board".

If I've told my kids once, I've told them a million times: don't fall into the trap of using hyperbole.
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Offline john e. holliday

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Re: stunt plane suggestion for a .15?
« Reply #67 on: January 11, 2017, 09:38:08 AM »
Welp  wwwar, save your 10 bucks. It's true I haven't built nor flown a Challenger .15; but my observation is

based on the possible specs of the model. So, please help me judge the model by it's actual specs; such as what

the wing area is, and also what is the percentage of the airfoil used. This way I can calculate what the wing loading

would be for a 25 oz model.  If I like the potential wing loading,  I can decide to possibly build a Challenger .15 in the

future.   Thanks in advance for the Challenger .15 specs.

Tony :)

Do a search for challenger 15  as from what I've read Walter Umland had a kit and I thought I seen where Mike Griffith may have had one.
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Offline paw080

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Re: stunt plane suggestion for a .15?
« Reply #68 on: January 11, 2017, 06:18:17 PM »

Hi John E. Holliday,  I want to thank you for the search suggestions;

So Thank You!  :)

I did find what I was looking for;

Tony

Offline paw080

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Re: stunt plane suggestion for a .15?
« Reply #69 on: January 11, 2017, 07:15:13 PM »

 Not a terrible idea, but I'm betting 10 bucks that Tony here has never built and/or flown a Challenger .15.  D>K


Well WWWarbird, I did checkout the specs on the Challenger .15.  First of all,

I think you did a lovely job on the thoughtful finish of your Challenger .15 however,

I learned that the model has a wing area of only 220(or is it 230) sq"s.  Sorry but

that is a bit small for most modern .15 engines.  Please heed my advice on wing loading,

Your Challenger .15 is close to the same size as a Jr Flite Streak,  But you have taken

your model to 15.72 ozs/sq'.  That is in the Mini Elephant category(I know, I've built a few mini elephants myself).  ;D

best of luck. Tony


Hi there Chris, I tried to find performance reviews of your TT .15 mk V.

I couldn't find any, so I can only guess based on similar engines.

If your TT .15 mk V has decent power for a bushed baffled engine,

it should be right at home with a 250-300 sq" wing area design.  So, if the

 TT .15 is on the mediocre power side, you still have a lot of profile designs

and a few kits to consider as suitable.

For a mediocre power .15, I suggest you try to stay below 9ozs/sq'.  Here's a few examples

of some of my profile models that are under 9 ozs/sq': Jr Flite Streak 11 ozs, Veco

 Tomahawk 20.5 ozs, Full size Flite Streak 20.8 ozs .   Keith Trostle is serious when he

says that most good flying 1/2A stunt models have 230-250 sq"s of wing area. I play

with a Ringmaster Jr that is modified(placed on a diet) for being powered by a Paw .049sbr

diesel the has a ready to fly weight(sans fuel) of 7.2 ozs. It fly's fast and is very aerobatic

on 44' X .008" lines. Yet, I can tell that it will fly much better with 30 more sq"s wing area.

So, ending this tome, I suggest choosing from the many good suggestions with 250-320 sq"s

 of wing area.  Best of luck;

Tony :)
« Last Edit: January 13, 2017, 11:38:53 AM by paw080 »

Offline Target

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Re: stunt plane suggestion for a .15?
« Reply #70 on: January 11, 2017, 08:11:41 PM »
I'm leaning towards @ 325-350 sq. in for wing area.
I have the other Schnurle  ported .15 on my combat wing, and if for some reason I need more umph, I can either swap the engines, or trim the wing tips a bit as needed (providing the plane isn't a lead sled).
I plan to use foam and vacuum bagging for most all of the components, and the plane will be an exercise in applying what I know about bagging sailplane wings to U control parts.
So the first one might be either too heavy, or too flimsy, but I will be OK with that, using it as a learning tool.

Might be a while before I can get to this anyway.

Kind Regards,
Chris
Regards,
Chris
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Re: stunt plane suggestion for a .15?
« Reply #71 on: January 12, 2017, 06:51:31 PM »
Those'r a clone of the OS max 15 , I think . Engine Test the OS pulls surprising rpm on a 9x4 in comparison to the 20 & 25 .

Yoursll need a bit of run in of course , so a 8 x 4 there . But see if its happy on a 9x4 when its had half a imperial gallon thru it .

Offline wwwarbird

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Re: stunt plane suggestion for a .15?
« Reply #72 on: January 14, 2017, 08:29:12 PM »

Well WWWarbird, I did checkout the specs on the Challenger .15. I learned that the model has a wing area of only 220(or is it 230) sq"s.



Tony :)

 I'm not sure where you think you found the specs Tony, but the Challenger .15 wing is 320 square inches.
Narrowly averting disaster since 1964! 

Wayne Willey
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Re: stunt plane suggestion for a .15?
« Reply #73 on: January 14, 2017, 09:16:43 PM »
You two are a crack up...
Yes, the challenger has 320 squares and a 35" span as per Walter's website. So a little more than a 9" chord average.
My plan will likely be closer to 40" span, and 9" root with 7" tips, I'm planning. That gives me 320 squares, and a 5:1 aspect ratio.

Planning on external (top) bellcrank for the first one, so I can just do a one piece wing layup. Following the K.I.S.S. plan for the first one. Fuse mounted landing gear legs, probably carbon for the exercise. Likely a combo wood/foam/glass/carbon layup for the fuse, and probably all foam and glass tail pieces.
That is my plan for now. More to follow.
Regards,
Chris
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Offline wwwarbird

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Re: stunt plane suggestion for a .15?
« Reply #74 on: January 14, 2017, 10:07:16 PM »
I have a Thunder Tiger .15 collecting dust, and I thought it'd be nice to build something to get it in the air. It's an Asian engine, not a lighter weight Cox, Novell, or Fox. Weights 3.9 oz before muffler, plug, and venture/needle.
Prefer a profile design, flapless, and actually a kit would be nice.

But as long as it's quick build, short kit or even plans is ok. I could vacuum bag a foam/carbon wing for it if needed.
I want something that flies GREAT, with proper tuning.
Thanks in advance.

Was wondering about the small Magician or Shark, or ?

HNY,
Chris

 I was just getting the facts straight back there Chris.

 Going back to the very beginning of this thread, it was my original understanding that you're looking for a GREAT flying, fairly simple and quick to build .15 size design to use for blowing the dust off your 'ol Thunder Tiger. As usual though, with most things here, it all got overly complicated very quickly.
 We're talking about finding a good .15 size airplane here, not the next "Igor Beater". Initially you were even wondering about the .15 size Magician or Shark. They're both neat old models, but are nowhere near the performers that the easy building Challenger is.
 
 I'll stick with my original suggestion, I guarantee you wouldn't regret it, and I hope you have fun with whatever you end up choosing to build.  
Narrowly averting disaster since 1964! 

Wayne Willey
Albert Lea, MN U.S.A. IC C/L Aircraft Modeler, Ex AMA member

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Re: stunt plane suggestion for a .15?
« Reply #75 on: January 14, 2017, 10:56:55 PM »
And if I were going with something to buy, it would probably be the Challenger.
But it sounds like Walter may still be down, and not producing kits currently? Unless you know otherwise?
Regardless, I sort of want to give this idea I have a shot, and a simple, smaller profile is just the ticket.
If you want to lose your Challenger plans and mail 'em west, I'll be glad to use the dimensions on my composite construction.
One thing I don't quite understand, is if and/or why there needs to be a flat stock behind the actual thicker part of the airfoil on the wing, since there are no flaps. It seems to add square inches, and you could easily have them hinged as active flaps, I guess. But why have the double reflexed profile shape? It seems prevalent in many stunt planes of yore.
Speaking of Igor, I think his smaller designs actually skip that mentioned feature. Combat wings don't usually have it either. In all accounts, combat wings turn sharply. Hmm. I'd sure like to know about that.
I didn't mean to ruffle any feathers, not yours or anyone's. Just got a chuckle out of your banter with Tony and his with you. Clearly you both want to assist me in my original request, and I believe you both did in reality. So thanks for that.
Respectfully,
Chris
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Offline paw080

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Re: stunt plane suggestion for a .15?
« Reply #76 on: January 15, 2017, 01:50:07 PM »
I'm not sure where you think you found the specs Tony, but the Challenger .15 wing is 320 square inches.


Hi War, now I actually feel better that the Challenger is 320 sq"s and not 230sq".

this makes a big difference in performance. I misread the spec details on the pdf plans

on Walter Umland's site. But, please do not assume that I don't know what a good flying

.15 powered profile is like.  To start with, I've flown Fast, F2d, and 1/2A combat, in the

TD .049 35' lines days.  I've built and flown .15 powered profiles that have a bit more

 wing area and are all lighter than your Challenger .15.  These models are all powered by

 sport or high performance(for 1980s...) Diesel engines.   So, now that rant is over with;

I can add your Challenger .15 to the list of models that I recommend for Chris Behm's

TT .15 mk V engine. Good luck;

Tony  :)   

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Re: stunt plane suggestion for a .15?
« Reply #77 on: January 15, 2017, 08:16:52 PM »

 One thing I don't quite understand, is if and/or why there needs to be a flat stock behind the actual thicker part of the airfoil on the wing, since there are no flaps. It seems to add square inches, and you could easily have them hinged as active flaps, I guess. But why have the double reflexed profile shape?


 Chris,

 It's designed that way with the idea of keeping the overall design simple, aka "K.I.S.S.". That additional flat T/E stock is commonly known as "fixed" flaps. Designing a wing this way keeps the wing construction "simple" and easy to build because the ribs are all the same dimension, except of course for the center few ribs which are 1/16" smaller all the way around to allow for the center sheeting.
 "Hershey Bar" is also a nickname for this type of wing design, because viewed from above it's essentially just a long rectangle, like a Hershey Bar. The Challenger's fixed flaps could be hinged and made to work but are completely unnecessary in this "K.I.S.S." design. In this case, and on a LOT of other designs, they are more for cosmetic appearance and design with an added bonus of a bit more wing area.

 Also, I'm pretty sure Walter is up and running again. Maybe not at full speed yet but Keith did order some more Challenger rib sets just the other day.

 
 And Tony,

 I'm glad you feel better.  :)
Narrowly averting disaster since 1964! 

Wayne Willey
Albert Lea, MN U.S.A. IC C/L Aircraft Modeler, Ex AMA member

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Re: stunt plane suggestion for a .15?
« Reply #78 on: January 15, 2017, 10:15:18 PM »
Thanks for the explanation. I had the same discussion with a control line flying buddy and he says the same thing, word for word mostly.
I'd just think that having that concave kink in the airfoil would be detrimental on a fixed section. I can see where on active flaps, when the top of the profile and flap are smooth, you'll get a tremendous boost in generated lift by the cambering of the profile generated.
So, other than making the plan view more pleasing, and keeping the ribs the same (and machineable in a "stack"), I don't see the reason to do this. Especially if any other parts are going to be laser cut (in which case, you'd might as well make the wing with a proper taper).
Building a foam wing, I don't see a need to add a flat section to accomplish the trailing edge sweep. I can with balsa construction for the reasons you mentioned though.
Maybe I'll ping Walter for some plans.
Thanks!
Chris
« Last Edit: January 16, 2017, 12:13:08 AM by Chris Behm »
Regards,
Chris
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Re: stunt plane suggestion for a .15?
« Reply #79 on: January 15, 2017, 11:26:00 PM »
Hi Chris,

When you mentioned combat wings it reminded me of my project some years ago to find an easy to build cheap model. A friend mentioned the he would like a plane that flies well enough to practice lower bottoms without worrying abut writing off an expensive plane. I took a combat style wing and built a very basic model around that. I built it for a .25 to .30 size engine and called it the Eze 25. The prototype had an Enya .30 SS in it and it flew well enough for some decent practicing. Eventually I made a smaller .15 size version with a MVVS .15 in it and later a .40 size as well. The .40 size did not fly well and I think that the ice cream cone airfoil did not work well when scaled up and flown at the slower stunt speeds. However the .15 size and .25 size flew great. I can mail you the plans and how to make the leading edged foam parts if you like. I still have your email address, so just let me know.

Regards,
Keith R
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Re: stunt plane suggestion for a .15?
« Reply #80 on: January 15, 2017, 11:27:59 PM »
Here are a few pics.........

Keith R

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Re: stunt plane suggestion for a .15?
« Reply #81 on: January 16, 2017, 12:16:31 AM »
Emailing me a pdf of plans would be fantastic, Keith, thank you.
I'll probably go a bit off trail, but having a known performing wing profile and plan form for the size plane I want to build is a great head start. Thanks.
Regards,
Chris
Regards,
Chris
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Re: stunt plane suggestion for a .15?
« Reply #82 on: January 16, 2017, 10:37:49 AM »
Hi Chris,

I'll do that for sure and I had a few more requests as well, so I'll just add a bit to the basic plans with some extra photos and diagrams etc. I'll sort that out by tomorrow.

Keith R
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Re: stunt plane suggestion for a .15?
« Reply #83 on: January 16, 2017, 11:30:06 AM »
No rush, thank you!

R,
Chris
Regards,
Chris
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Re: stunt plane suggestion for a .15?
« Reply #84 on: January 16, 2017, 04:55:59 PM »
Hi Chris,

When you mentioned combat wings it reminded me of my project some years ago to find an easy to build cheap model. A friend mentioned the he would like a plane that flies well enough to practice lower bottoms without worrying abut writing off an expensive plane. I took a combat style wing and built a very basic model around that. I built it for a .25 to .30 size engine and called it the Eze 25. The prototype had an Enya .30 SS in it and it flew well enough for some decent practicing. Eventually I made a smaller .15 size version with a MVVS .15 in it and later a .40 size as well. The .40 size did not fly well and I think that the ice cream cone airfoil did not work well when scaled up and flown at the slower stunt speeds. However the .15 size and .25 size flew great. I can mail you the plans and how to make the leading edged foam parts if you like. I still have your email address, so just let me know.

Regards,

Keith,
Hmmmm...That "Ice cream Cone" airfoil scaled up to 650 square inches pretty good for the Trivial Pursuit and works just fine!  It does suck up power like a sponge and needs plenty in front of it!  It supports a heavy ship with lots of power however!  Mine weighed 74 ounces and still flew very well with a PA65, and a RO Jett 65.  Ted's flew well enough to win the Nationals with a RO Jett 65!  I think it weighed very near 70 oz.
I don't think the problem was the airfoil!   Maybe all those electrons get in the way!  LL~ LL~ LL~ LL~

Randy Cuberly
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Re: stunt plane suggestion for a .15?
« Reply #85 on: January 16, 2017, 05:46:24 PM »

I'd just think that having that concave kink in the airfoil would be detrimental on a fixed section. I can see where on active flaps, when the top of the profile and flap are smooth, you'll get a tremendous boost in generated lift by the cambering of the profile generated.
So, other than making the plan view more pleasing, and keeping the ribs the same (and machineable in a "stack"), I don't see the reason to do this. Especially if any other parts are going to be laser cut (in which case, you'd might as well make the wing with a proper taper).
Building a foam wing, I don't see a need to add a flat section to accomplish the trailing edge sweep. I can with balsa construction for the reasons you mentioned though.


 Wow. That's a LOT of thinking for a .15 size plane Chris, severely overthinking IMHO. I guess your K.I.S.S plan has disappeared somewhere, carry on.  H^^
Narrowly averting disaster since 1964! 

Wayne Willey
Albert Lea, MN U.S.A. IC C/L Aircraft Modeler, Ex AMA member

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Re: stunt plane suggestion for a .15?
« Reply #86 on: January 16, 2017, 09:06:34 PM »
Thinking before acting costs nothing but time and saves time in the long run.
And at this time, I need this diversion.
R,
Chris
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Chris
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Re: stunt plane suggestion for a .15?
« Reply #87 on: January 16, 2017, 10:42:49 PM »
Hi Randy,
The Trivial Pursuit airfoil is not the "ice-cream cone" section I'm talking about. I'm referring to the normal section used on the Russian style combat wings. The power on the .40 size Eze was a slimer in fact!  #^ When I sawed the snout off and electrified it, it was still not a nice plane like the smaller ones. It did however improve a lot if flown faster, so it was quite interesting.

There was a good discussion on this in the engineering section http://stunthanger.com/smf/engineering-board/ice-cream-cone-airfoils/

Keith R
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Re: stunt plane suggestion for a .15?
« Reply #88 on: January 17, 2017, 08:53:45 AM »
O.K. Here is a basic plan in pdf format. I've left certain parts in colour to show differences, and I must stress that it is a rough plan right now, but you can get an idea of how it goes together. I've also added an old file to let you print the parts on an A4 printer and then join them together. There is also a file for the Eze 25 on my website here at http://www.keithrenecle.co.za/files/Eze%2025.pdf. This shows how to cut the foam cores and there are a few photos from the original build. If you do want to actually build one then I do have more info so just mail me.

Keith R
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Re: stunt plane suggestion for a .15?
« Reply #89 on: January 17, 2017, 06:11:58 PM »
THANKS A LOT, Keith!!!

Vr,
Chris
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Chris
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Offline Tim Wescott

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Re: stunt plane suggestion for a .15?
« Reply #90 on: January 17, 2017, 06:51:37 PM »
O.K. Here is a basic plan in pdf format. I've left certain parts in colour to show differences, and I must stress that it is a rough plan right now, but you can get an idea of how it goes together. I've also added an old file to let you print the parts on an A4 printer and then join them together. There is also a file for the Eze 25 on my website here at http://www.keithrenecle.co.za/files/Eze%2025.pdf. This shows how to cut the foam cores and there are a few photos from the original build. If you do want to actually build one then I do have more info so just mail me.

Keith R


FWIW this gets my seal of approval.  Nice, basic, light, what more could you want?

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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

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Re: stunt plane suggestion for a .15?
« Reply #91 on: January 17, 2017, 10:43:09 PM »
Thanks Tim!  ;D Just a little more info. You will notice the lack of nose doublers. I just figured that it was not worth worrying about with the low life expectancy. The pine nose section adds quite a bit of strength and also holds the bellcrank in place rather well. The original model was pranged into our tar circle and it looked quite bad as you can see in the pic below. It actually repaired quite easily and still flew for a few years more until someone eventually totalled it.

Our club also got our local good builder Roy Harvey to build a bunch of them to sell to beginners and he did not like the straight lines too much so he curved the wing trailing edge and tapered the stab and elevator. I still have the checkerboard pattern one although it has taken a beating. Just btw, that little Enya .30 SS is such a great engine as well. The others were powered by the Enya .15 plain bearing engines.

Keith R
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Re: stunt plane suggestion for a .15?
« Reply #92 on: January 18, 2017, 11:18:44 AM »
That trailing edge does help the looks.   H^^
John E. "DOC" Holliday
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Re: stunt plane suggestion for a .15?
« Reply #93 on: March 17, 2017, 10:37:34 AM »
Not that I'm partial or anything, but here is another suggestion.. Basically a re-worked Shark .15

https://store.flying-models.com/catalog/product_info.php?cPath=21&products_id=82


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Re: stunt plane suggestion for a .15?
« Reply #94 on: March 24, 2017, 03:56:23 PM »
I'm probably a bit late to the party, but I built this Brodak Flite Streak Junior in 6 days to teach my daughter and granddaughter to fly.  I used an old Fox .15 for power and surprisingly the little plane flies the full pattern quite well!  It also survived several training flights, and my girls did like the "pink silk" covering!

Don

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Re: stunt plane suggestion for a .15?
« Reply #95 on: March 24, 2017, 10:30:41 PM »
Thanks Mark and Don for the suggestions.
I'm pretty certain I'll use this build as a composite test bed before possibly doing a bigger one....
R,
Chris
Regards,
Chris
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Re: stunt plane suggestion for a .15?
« Reply #96 on: April 01, 2017, 04:02:26 PM »
I picked up a Walter Umland .15 sized Magician that might be used to break in the TT .15 before I build my composite wonder....
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Chris
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Offline frank mccune

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Re: stunt plane suggestion for a .15?
« Reply #97 on: April 07, 2017, 11:29:56 AM »
      Hello:

      May I suggest that you try a Shark .15 and/or a full sized Flite Streak.

      I have flown many flights on a Shark .15 with Fox baffle .15, and a ST G 15 glow and
a diesel and it was a very good combination.  I think that it has 270 sq. inches of wing.

      At present I am flying a full size Flite Streaks with ST G20/15D or ST G20 .23 glow engines on 60' lines. I got a RTF FS that is very light and is powered by a ST G20/15D and flies very well.  This plane is easy to get in the air and will fly very well.  I also have a few ST G20/.23 glow engines that will drop in place of the other ST engines if I feel a need for more power.  The G20/.23 is a really sweet engine! Of course, I have a Brodak .25 that I do not use that may be the hot set up for the Flite Streak.  So many choices, so little time! Lol
 
    Try the above suggestions and have a ball.

    Perhaps an older Sterling Ringmaster or Mustang would also fly well if built very lightly.  Start with 52' lines to determine how well the planes fly.  You can go to 60' lines after you get things dialed in. I flew my Shark 15 on 52' lines and it was a great performer.

                                                                                                             Good luck,

                                                                                                             Frank


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