Re: CEF speed contest Design Discussions (2014)

Marleysky Fri Jan 30, 2015 9:16 pm

JPvelo wrote:
JPvelo wrote:Stay tuned.... Seems like the most important thing is aerodynamics.

Jim

I have read the rules for 2015. Given up on the spruce goose with 5 .010's. Read the rules again, and found no reference to construction materials. Are other materials legal to use? Or is it assumed all profile racers are balsa? I'm asking here because the 2015 rules thread is locked. Thanks.

getback Fri Jan 30, 2015 9:28 pm

Locked ??? https://www.coxengineforum.com/t7743-cef-profile-scale-speed-2015?highlight=reed+speed+215

**RknRusty** Fri Jan 30, 2015 10:08 pm

Marleysky wrote:
JPvelo wrote:
JPvelo wrote:Stay tuned.... Seems like the most important thing is aerodynamics.

Jim

I have read the rules for 2015. Given up on the spruce goose with 5 .010's. Read the rules again, and found no reference to construction materials. Are other materials legal to use? Or is it assumed all profile racers are balsa? I'm asking here because the 2015 rules thread is locked. Thanks.

You can build it out of anything. It's just stand-off scale, in other words it should look about like the full size plane from casual observation. Colors and markings are not required to be authentic at all. I thought craft foam board would be good and light before I built my Mustang, but it turns out it weighs about the same as balsa on my electronic food scale.
Hope that helps.
Rusty

JPvelo Fri Jan 30, 2015 10:31 pm

RknRusty wrote:
Marleysky wrote:
JPvelo wrote:
JPvelo wrote:Stay tuned.... Seems like the most important thing is aerodynamics.

Jim

I have read the rules for 2015. Given up on the spruce goose with 5 .010's. Read the rules again, and found no reference to construction materials. Are other materials legal to use? Or is it assumed all profile racers are balsa? I'm asking here because the 2015 rules thread is locked. Thanks.
You can build it out of anything. It's just stand-off scale, in other words it should look about like the full size plane from casual observation. Colors and markings are not required to be authentic at all. I thought craft foam board would be good and light before I built my Mustang, but it turns out it weighs about the same as balsa on my electronic food scale.
Hope that helps.
Rusty

Exactly. Thanks Rusty.

JPvelo Fri Jan 30, 2015 10:35 pm

roddie wrote:Jim, is that the same gullwing construction as your 1st? Looks a beam-mount is planned!! NICE!!!

Yes, same construction. It's for a horseshoe backplate. It's going to have the same intake as the staggerwing and I'm going to try and bury the bladder in the nacelle behind the engine.

Jim

JPvelo Wed Feb 18, 2015 4:54 pm

Found a little time to work on Super Corsair 2.0 today:
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**RknRusty** Wed Feb 18, 2015 10:10 pm

Oh great, I love to watch your work. Carry on. I'll be standing by for build updates.
Rusty

ian1954 Thu Feb 19, 2015 4:10 am

Has no one else started building yet?

getback Thu Feb 19, 2015 8:46 am

Wow Jim that's got a lot of dihedral in the wing ,Looking good as always ! I have not started yet need to look at some more designs/have not decided on what to build ?

OVERLORD Thu Feb 19, 2015 2:08 pm

ian1954 wrote:Has no one else started building yet?

All right, all right, I have

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rsv1cox Thu Feb 19, 2015 2:24 pm

ian1954 wrote:Has no one else started building yet?

Laid this out this morning. Thinking about hanging my Super tigre 60 on it, or maybe even a Cox Black Widow. Smile

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Oldenginerod Thu Feb 19, 2015 3:15 pm

OVERLORD wrote:
ian1954 wrote:Has no one else started building yet?

All right, all right, I have

I'm not too sure that Cox produced a pulse jet.

Mind you, the final result (crash & burn) is very familiar to me. lol!

Looking at your picture, I can see Ian ducking for cover.

Rod.

Mike Mulligan Thu Feb 19, 2015 4:03 pm

This one is coming along pretty well for this go round. It is the Red Baron Mustang and it was started for the last contest. I've got it off the shelf and progress is being made to have it flying for this go round.

I've sketched up another plane for the Tee Dee class too. Pics of that as progress warrants...

Mike

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CEF speed contest Design Discussions (2014) - Page 12 101_0311

ian1954 Thu Feb 19, 2015 6:50 pm

Oldenginerod wrote:
OVERLORD wrote:
ian1954 wrote:Has no one else started building yet?

All right, all right, I have

I'm not too sure that Cox produced a pulse jet.

Mind you, the final result (crash & burn) is very familiar to me.

Looking at your picture, I can see Ian ducking for cover.

Rod.

https://www.youtube.com/watch?v=TX_zI4tIueY

getback Fri Feb 20, 2015 8:21 am

OK I think I have decided on this one TD or Reed ?

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Of coarse it comes with a movie Very Happy

Maybe I can get it drawn up today Flying

Eric

JPvelo Mon Feb 23, 2015 6:29 pm

Is that a bladder in your nacelle or are you just glad to see me....

It's hard to see but there's a fully inflated bladder in there. Next challenge, how to best hide the bellcrank aerodynamically while still leaving it exposed per the rules.
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Jim

pkrankow Mon Feb 23, 2015 6:48 pm

Dumb question: How do you change out the bladder when it breaks?

Phil

JPvelo Mon Feb 23, 2015 7:02 pm

pkrankow wrote:Dumb question: How do you change out the bladder when it breaks?

Phil

The check valve comes off so the Tee fitting can be weaseled out the front.
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**RknRusty** Mon Feb 23, 2015 7:15 pm

And they rarely ever burst. Those little Fourmost 1-way valves really make fueling easy don't they. Good design.
Rusty

P.S. When is the qualifying photo due?

JPvelo Mon Feb 23, 2015 7:51 pm

RknRusty wrote:And they rarely ever burst. Those little Fourmost 1-way valves really make fueling easy don't they. Good design.
Rusty

P.S. When is the qualifying photo due?

Thanks Rusty, photos are due December 14th. Videos must be in by December 31st

Jim

JPvelo Tue Feb 24, 2015 2:15 pm

The front end is all mocked up. I didn't realize the fuel line would lay so flat. If I were to do it again or if anyone wants to copy it I would hide the needle and fill valve behind the cylinder. I decided to put the bellcrank as flat against the wing as possible.
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**RknRusty** Tue Feb 24, 2015 2:32 pm

JPvelo wrote:The front end is all mocked up. I didn't realize the fuel line would lay so flat. If I were to do it again or if anyone wants to copy it I would hide the needle and fill valve behind the cylinder. I decided to put the bellcrank as flat against the wing as possible.

It looks great. I find it easier to operate the needle on the inboard side, but the fill valve would be hidden better aerodynamically behind the cylinder.
Rusty

roddie Tue Feb 24, 2015 6:09 pm

I like that ram-air set-up. I liked it on the Beech too.. It looks great, as well as being functional. How will you manage the lead-outs with that bellcrank position? I was thinking possibly a 2nd set of guides just before where the wing cants up to the fuse. It would have to be strong though.. so as not to pull out of the wing. Maybe I'm seeing it all wrong? It seems that's the only way you'd achieve perpendicularity to your bellcrank bearing.

**RknRusty** Tue Feb 24, 2015 9:46 pm

roddie wrote:... It seems that's the only way you'd achieve perpendicularity to your bellcrank bearing.

Maybe that's why he's got 3 holes on one side of the bellcrank. But I don't think the angle is as critical as one might think, as long as the line length can be adjusted at the handle.

JPvelo Tue Feb 24, 2015 10:53 pm

RknRusty wrote:
roddie wrote:... It seems that's the only way you'd achieve perpendicularity to your bellcrank bearing.
Maybe that's why he's got 3 holes on one side of the bellcrank. But I don't think the angle is as critical as one might think, as long as the line length can be adjusted at the handle.

There's a very good reason my bellcrank has three holes on the up side... That's how I found it in the used bin at Franks Hobby House!!! lol!

If this was a stunter like Rustys' speed plane I would be more concerned with the angle. The elevator moves so little on one of these flights I don't think it will matter much. Famous last words....

Jim

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