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Cox Engine of The Month
CEF speed contest Design Discussions (2014)
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Re: CEF speed contest Design Discussions (2014)
JPvelo wrote:
Good question Mike and good point Phil.
I hadn't really thought about it until now. I lifted the rules for this from 1/2a profile proto and we've adapted them along the way to incorporate scale and try to get more speed from a reed powered plane.
The 12.5 biplane span is from the proto rules. That's a combined span of 25 inches. To me it would make sense to change the biplane rule to minimum combined wingspan of 25" with minimum 45 square inch wing area. That way you can make top and bottom span whatever you like as long as they hit the 25" combined span mark.
Thoughts?
Jim
I think I agree with Phil. I believe the 45 squares rule, and the requirement to look 'scale', would do a pretty good job of keeping everything fairly even. There were a few planes that were called "sesquiplanes" (As in one and a half wings) that could be accurately modelled with really small lower wing, but the spider's web of struts on those things would be penalty enough!
By the way, after doing some scribbling it does look like the 24" combined span could make it a bit tough to maintain a scale look without going way over 45 squares, for whatever that may be worth. Things start to look like two-winged sailplanes...
Discaimer: The plane I had in mind to build (Beck-Mahoney Scorceress) flew with both equal span wings and with a shorter lower wing. Either way you decide, it won't really affect what I had in mind, though with the shorter lower span I can get down to about 48 squares without it starting to look too funny! (Kinda looks funny enough already)
Might only get one flight out of it; what are the chances of a successful landing on those bottom wings!
Cheers guys!
Mike
Re: CEF speed contest Design Discussions (2014)
JPvelo wrote:Details of my high tech intake system:
Firewall has two holes, an intake for the engine and an intake for the "airbox" that directs air to the engine.
Detail of the airbox cut into the cheek block.
The intake tube.
What it looks like all put together.
Jim
Really nice! Simple and elegant. Can I ask about your fuel storage plans?
Re: CEF speed contest Design Discussions (2014)
Mike, cool plane!
I think it's best to just leave it at 12.5 minimum top and bottom and if you want to extend the top for scale look you can. Remember the model has to be recognizable as the subject, not an exact scale replica. That doesn't mean you can make a two wing sailplane and try to pass it of as a stearman.
Jim
I think it's best to just leave it at 12.5 minimum top and bottom and if you want to extend the top for scale look you can. Remember the model has to be recognizable as the subject, not an exact scale replica. That doesn't mean you can make a two wing sailplane and try to pass it of as a stearman.
Jim
JPvelo- Diamond Member
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Re: CEF speed contest Design Discussions (2014)
Man I see more cool stuff in this thread.
This thing looks like two planes that got stuck...... well, just stuck!
This thing looks like two planes that got stuck...... well, just stuck!
_________________
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...and never Ever think about how good you are at something...
while you're doing it!
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...and never Ever think about how good you are at something...
while you're doing it!
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Re: CEF speed contest Design Discussions (2014)
JPvelo wrote:Mike, cool plane!
I think it's best to just leave it at 12.5 minimum top and bottom and if you want to extend the top for scale look you can. Remember the model has to be recognizable as the subject, not an exact scale replica. That doesn't mean you can make a two wing sailplane and try to pass it of as a stearman.
Jim
Hahaha! Don't put ideas in my head!
12.5" for both sounds good.
Re: CEF speed contest Design Discussions (2014)
Jim that system does look good, plenty of air flow and exhaust relief , but I am still with Roddie I think even if you had a pipe going directly into the vent ... unless you can figure how rich to set the engine before take off and not being able to adjust it in flight I cant see the factor , other than floating the reed . just my ( but it does look damn cool ) Getback .....
getback- Top Poster
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Re: CEF speed contest Design Discussions (2014)
Mike,
I plan on using an external bladder secured through the spring end of a safety pin.
I plan on using an external bladder secured through the spring end of a safety pin.
JPvelo- Diamond Member
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Re: CEF speed contest Design Discussions (2014)
JPvelo wrote: That doesn't mean you can make a two wing sailplane and try to pass it of as a stearman.
Jim
Look what I found! That's as close to a two wing sailplane as I have ever seen!
Re: CEF speed contest Design Discussions (2014)
JPvelo wrote:Mike,
I plan on using an external bladder secured through the spring end of a safety pin.
Nice. Simple and reliable is probably the best way to go, when you get right down to it.
Mike
Re: CEF speed contest Design Discussions (2014)
Oh, and speaking of simple and reliable (not), here are some pics of the Red Baron progress.
Since intakes seem to be en vogue right now, here is the ducting for this bird.
The part above the engine is the floor of the intake duct. The top will follow the fuselage line to just behind the spinner. I just couldn't resist using the scale inlet!
Since intakes seem to be en vogue right now, here is the ducting for this bird.
The part above the engine is the floor of the intake duct. The top will follow the fuselage line to just behind the spinner. I just couldn't resist using the scale inlet!
Re: CEF speed contest Design Discussions (2014)
Mike Mulligan wrote:
Look what I found! That's as close to a two wing sailplane as I have ever seen!
I've scammed rides in anything I could, figuring I'd fly anything once. But I don't know as I'd try that one...
The "Not As Brave As He Thought" Mark
batjac- Diamond Member
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Re: CEF speed contest Design Discussions (2014)
Thanks for the info guys regarding the electric props. So I will not be using one.
Mike, that Red Baron is looking great. As with your other model, beautiful work!!
Theo
Mike, that Red Baron is looking great. As with your other model, beautiful work!!
Theo
Theo Kleynhans- Gold Member
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Re: CEF speed contest Design Discussions (2014)
I finished my Nemesis wing last night. This was my first try to do an airfoil.
Now I need to start on the fuse and stab.
Theo
Now I need to start on the fuse and stab.
Theo
Theo Kleynhans- Gold Member
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Re: CEF speed contest Design Discussions (2014)
Very nice Theo!!
OVERLORD- Diamond Member
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Re: CEF speed contest Design Discussions (2014)
Theo Kleynhans wrote:I finished my Nemesis wing last night. This was my first try to do an airfoil.
Now I need to start on the fuse and stab.
Theo
Top notch awesome!
Phil
pkrankow- Top Poster
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Re: CEF speed contest Design Discussions (2014)
Looks way better than my first try! And second...and third...
Cribbs74- Moderator
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Re: CEF speed contest Design Discussions (2014)
Thank you for the kind words Guys.
I am trying to really make this a nice plane.
Theo
I am trying to really make this a nice plane.
Theo
Theo Kleynhans- Gold Member
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Re: CEF speed contest Design Discussions (2014)
Really looking sharp there Theo !!
getback- Top Poster
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Re: CEF speed contest Design Discussions (2014)
Hi Guys
I sanded the Stab last night of my Nemesis. It came out quite nice, but I am a bit worried, it is extremely soft and flexable. I used 3mm balsa. But I am hoping it will stiffen with the sanding sealer and paint.
Here are the wing and stab together:
Theo
I sanded the Stab last night of my Nemesis. It came out quite nice, but I am a bit worried, it is extremely soft and flexable. I used 3mm balsa. But I am hoping it will stiffen with the sanding sealer and paint.
Here are the wing and stab together:
Theo
Theo Kleynhans- Gold Member
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Re: CEF speed contest Design Discussions (2014)
Depending on the type of sealer and paint, yes it will stiffen. If you are using dope (fuel proof), or lacquers(generally not fuel proof) for the base coats it will soak in, harden and stabilize the wood. If you are using enamels it will not.
I do not know how well the polyurethane options work (both oil and water based) as I have not worked with balsa and polyurethane much. I know that using cornstarch with dopes and polyurethanes make a good sandable filler paint that will fill the grain fast for that perfect finish.
Phil
I do not know how well the polyurethane options work (both oil and water based) as I have not worked with balsa and polyurethane much. I know that using cornstarch with dopes and polyurethanes make a good sandable filler paint that will fill the grain fast for that perfect finish.
Phil
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Re: CEF speed contest Design Discussions (2014)
Thanks for the info Phil. I will not be using enamels, so the lacquers should stiffen the stab.
I finished the fuselage over the weekend. The plane is now starting to come together.
Here was the fuse with the slots cut for the wing. I fitted them to see what she looked like.
Then I finished with sanding the Fuse:
Now I guess I need to take some time and figure out how I will do the bellcrack and what I am going to do at the nose. I have not decided how I will mount the engine and what type of cowling I will do. This is now the difficult part for me.
Theo
I finished the fuselage over the weekend. The plane is now starting to come together.
Here was the fuse with the slots cut for the wing. I fitted them to see what she looked like.
Then I finished with sanding the Fuse:
Now I guess I need to take some time and figure out how I will do the bellcrack and what I am going to do at the nose. I have not decided how I will mount the engine and what type of cowling I will do. This is now the difficult part for me.
Theo
Theo Kleynhans- Gold Member
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Re: CEF speed contest Design Discussions (2014)
SLICK Theo!!!!! The airfoil-sanding job on your stab looks awesome! The whole model looks AWESOME!! One of my favorite stages of building a profile model, is the instant transformation that takes place.. when you slide the wing and stab into the fuse, after the fin/canopy is attached.
Re: CEF speed contest Design Discussions (2014)
That is a thing of beauty Theo!
Jim
Jim
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Re: CEF speed contest Design Discussions (2014)
Theo
I sanded a similar foil on the inboard side of the fin on my Baby Flite Streak. The outboard of the fin was left flat.That was intended to cause the air flowing over the curve to form a vacuum and theoretically pull the tail into the circle resulting in a slightly helpful outward yaw.
Yours is nicely shaped but i can only see the curved outboard side of the fin. Unless there is an equal foil on the inboard side, this rudder is going to yaw the tail out and the nose into the circle. Am I missing something? It wouldn't be the first time.
Rusty
I sanded a similar foil on the inboard side of the fin on my Baby Flite Streak. The outboard of the fin was left flat.That was intended to cause the air flowing over the curve to form a vacuum and theoretically pull the tail into the circle resulting in a slightly helpful outward yaw.
Yours is nicely shaped but i can only see the curved outboard side of the fin. Unless there is an equal foil on the inboard side, this rudder is going to yaw the tail out and the nose into the circle. Am I missing something? It wouldn't be the first time.
Rusty
_________________
Don't Panic!
...and never Ever think about how good you are at something...
while you're doing it!
My Hot Rock & Blues Playlist
...and never Ever think about how good you are at something...
while you're doing it!
My Hot Rock & Blues Playlist
RknRusty- Rest In Peace
- Posts : 10869
Join date : 2011-08-10
Age : 68
Location : South Carolina, USA
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