CEF speed contest anyone?

roddie wrote:Here's what I've got in mind... a profile variant, of course! Quart size plastic soda bottle-bottoms make sweet engine cowlings for this size!

Exactly what I'm talking about! A quart bottle sounds big for 15 inch span model but I could be wrong. Remember, the smaller it is the faster it will go.

Jim

To hit the span on a bearcat length works out almost perfect to span for scale. I crunched the basic numbers last night.

I think the square inches work out pretty well too. I wouldn't be surprised if there are several bearcat entries.

Phil

pkrankow wrote:To hit the span on a bearcat length works out almost perfect to span for scale.  I crunched the basic numbers last night.

I think the square inches work out pretty well too.  I wouldn't be surprised if there are several bearcat entries.

Phil

I really like the looks of the fastback corsairs, will probably build one.


I also got an idea for a second model today that will be referred to as "Project X" until it's unveiling at race time.

This looks more the size...

Would a muffler-pressure system be allowed... seeing that it is not internal to the engine?

Roddie,

Mufflers will probably limit the engine. Speed is loud and raunchy!!!!  

Just kidding, but I have never seen a muffler on a speed plane. Keep in mind I am new at this.

roddie wrote:Would a muffler-pressure system be allowed... seeing that it is not internal to the engine?

I've updated the rules to disallow mufflers and exhaust extensions. Full rules are posted here:
https://www.coxengineforum.com/t5898-cef-profile-scale-reed-speed-rules

Jim

Kim wrote:True...if it were exact scale...which I'm sure is the case with some models/kits.  I'm probably over thinking it, as I tend to do with lots of things in the early morning !!

I had a look on a few plans and I found out that planes originally designed as racers have a reduced wing surface compared to WW2 fighters. Their span is generally smaller than the length of the fuse. WW2 fighters are the other way around. In order to keep the imposed wing area and stick to the exact scale, you end up with a long fuse. I assume enlarging the wing to meet the required surface and keeping a similar-to-the-original-shape  at the same time would be allowed. The rules say: "Models will be of an actual aircraft type and must be recognizable as the subject being modeled."

Lieven

OVERLORD wrote:

Kim wrote:True...if it were exact scale...which I'm sure is the case with some models/kits.  I'm probably over thinking it, as I tend to do with lots of things in the early morning !!

I had a look on a few plans and I found out that planes originally designed as racers have a reduced wing surface compared to WW2 fighters. Their span is generally smaller than the length of the fuse. WW2 fighters are the other way around. In order to keep the imposed wing area and stick to the exact scale, you end up with a long fuse. I assume enlarging the wing to meet the required surface and keeping a similar-to-the-original-shape  at the same time would be allowed. The rules say: "Models will be of an actual aircraft type and must be recognizable as the subject being modeled."

Lieven

Yes, that is the intention of the rule. These are "stand off scale" models. But remember the 12 inches is a minimum, you can go longer if you wish. Also, you may build any plane you choose, not just WW2 era.

Jim

JPvelo wrote:

pkrankow wrote:To hit the span on a bearcat length works out almost perfect to span for scale.  I crunched the basic numbers last night.

I think the square inches work out pretty well too.  I wouldn't be surprised if there are several bearcat entries.

Phil

I really like the looks of the fastback corsairs, will probably build one.


I also got an idea for a second model today that will be referred to as "Project X" until it's unveiling at race time.

Its not a speed demon but Larry Rengers Corsair is a thing of beauty.

Thanks Jim! I needed a jump-start! I've actually chosen balsa, and am using my calculator for something more enjoyable!

RknRusty wrote:Here is a great resource for calculating wing things:

http://www.airfieldmodels.com/information_source/math_and_science_of_model_aircraft/formulas/straight_tapered_and_delta_wing_area.htm

Here's another:

http://adamone.rchomepage.com/

I found an easy way to calculate wing area:

Copy your scale wing on a sheet or if needed more sheets of paper. Then cut out the wing with scissors. After removing the cut out wing, stick the paper to your cutting math and make sure to line up at least one wing side with the printed lines of your cutting math. Now just count the squares.



Lieven

OVERLORD wrote:I found an easy way to calculate wing area:

Copy your scale wing on a sheet or if needed more sheets of paper. Then cut out the wing with scissors. After removing the cut out wing, stick the paper to your cutting math and make sure to line up at least one wing side with the printed lines of your cutting mat. Now just count the squares.

Lieven

Wing area for dummies, Thanks Lieven.

Rusty

Well I'm glad it at least garnered some interest and explanation...I was feeling fairly dense as I punched the "send' button !!!

Kim:

I view purpetual "denseness" as an invalueable asset. I keeps one from feeling like a "know it all".  

SD

Possibly, but it can also make a person take a long trip around a simple solution.  

I liken it to a file on a balky hard-drive that will finally break loose and run.

Not to mention that females can get real persnickety about the whole "remember my name" thing ....

Hey Kim, I like the avatar!

Jim

 So, what's the general idea on the new planes? Are we going to post pictures of build threads or keep our speed planes "Top Secret"? Or both? 

Thanks Jim !!

My Top Secret "Reed Speed" Notebook, next to my Cox Flight Contest Logbook...BOTH reminding me to get out to the shop and lock the door behind me !!!!

duke.johnson wrote: So, what's the general idea on the new planes?  Are we going to post pictures of build threads or keep our speed planes "Top Secret"?  Or both? 

Don't know about anybody else, but I'll probably end up blabbing...I always do !!!!

duke.johnson wrote: So, what's the general idea on the new planes?  Are we going to post pictures of build threads or keep our speed planes "Top Secret"?  Or both? 

That's completely up to you. I'm building two planes. I will talk about one but not necessarily do a build thread. With the other one I have some ideas I may keep to myself. As far as engine/prop combos I ain't talkin'.

Need a smack talk and design thread now.

Phil