CEF speed contest Design Discussions

I actually started tonight, found out the washing machine make a great balsa dust collector, hopefully the Mrs. doesn't notice.
Here's something that may be of interest to some that want a sharp trailing edge and/or a uniform straight leading edge, its a handy little tool I learned from my Q500 days.
Hopefully the photos are pretty self-explanatory, use two pieces of wood that equal the width you want to cut the groove in and CA the exacto blade in place. When cutting the groove use several light passed and flip tool and repeat in case blade is slightly off center. Cut appx. 1/8" strip of 1/64 ply and press in, wick thin CA into strip....which I'm out of!

I got my cowl painted finally... it was a pain! Now I have to start masking-off the airframe for this color. I picked up some Tamiya masking tape at that hobby shop that's going out of business. I hope the tape works as well as I've read.




This tape was $3.00 after taking the 40% off.

Mark Boesen wrote:I actually started tonight, found out the washing machine make a great balsa dust collector, hopefully the Mrs. doesn't notice.
Here's something that may be of interest to some that want a sharp trailing edge and/or a uniform straight leading edge, its a handy little tool I learned from my Q500 days.
Hopefully the photos are pretty self-explanatory, use two pieces of wood that equal the width you want to cut the groove in and CA the exacto blade in place. When cutting the groove use several light passed and flip tool and repeat in case blade is slightly off center. Cut appx. 1/8" strip of 1/64 ply and press in, wick thin CA into strip....which I'm out of!

I like that.. It's sorta' like a Dubro hinge-slotting tool.

Cribbs74 wrote:I've got gear! Thanks Rusty!

5 separate pieces to make it up. I think I'll skip the pants and go commando...

All that's left is the tail skid, tip weight and the little triangle gear covers, they have a proper name, but it alludes me at the moment.

Spats - methinks!

Sounds about right Ian

Looking good Getback! I am using a nickle for tip weight and my planes are flying nice and level.

Jim

getback wrote:...Rusty the stick did you get my pm? ...

No, I just checked my inbox and my save folder. I don't have any PMs from you.
Rusty

Ok, I am done! Ready to race   

Added spats, tip weight and tailskid.

AUW is 5.3oz, I hope that it's heavy enough. I didn't set out for low weight. It's just what it built out to be. It's a light wind flyer for sure. I'll take a good picture for the judging, but it's not as pretty as I would have liked due to it being a rush job.

Cribbs74 wrote:Ok, I am done! Ready to race   

Added spats, tip weight and tailskid.

AUW is 5.3oz, I hope that it's heavy enough. I didn't set out for low weight. It's just what it built out to be.  It's a light wind flyer for sure. I'll take a good picture for the judging, but it's not as pretty as I would have liked due to it being a rush job.

I LOVE IT!!

That's beautiful, man. What happened to the smoky color you were so disheartened with the other day? It looks like a pretty quick little bipey too.
I'll get back on my Mustang tomorrow and race the deadline. I'm sure it'll be a pretty quick bash.
Rusty

I didn't know you were building a mustang, when did you decide this? I had to help jr. with the bike tonite so I didn't even touch it.

It's gonna be close!

Yeah Mark, here's my Mustang bits:
https://www.coxengineforum.com/t5910p720-cef-speed-contest-design-discussions#82802

There's the thread about my Stang. I drew it up over the Holidays, cut wood a couple of weeks ago. so it's a fuse, a wing motor mount and engine. I have a good old tach race engine for it. It might challenge. Got a fine thread NV from Hank Nystrom over at TT. Gotta hurry now. My Sunday is already dedicated to flying the you know what, so I'm working nights in the shop.
Fallin' asleep Rusty. See y'all tamale

cowling fitted.. other parts painted and drying on fixtures.   sheeeesh.. CRUNCH TIME!!!

Nice. I've been keeping an eye out for something that looks right for my cowl. So far it might be small a spray bottle of eyeglasses cleaner but haven't measured it yet. I might mold one out of balsa but not as sophisticated as Lieven's.

I'm looking forward to my stab/elevator build. I've never made one with the hinge material between two pieces of laminate before. I'm hoping this plane can be retired as an everyday trainer. I need a new plane that I can fly at the church yard. I'm expecting to make some good progress on it today.
Rusty

Good Luck Rusty, I'm running on adrenaline now... pulled an "all-nighter". I was thinking the same thing concerning using the model after the contest. I'd like to try the muffler with a pressure-tap. It won't fit inside my cowl though. I may have to swap to a non-SPI cylinder, but if I run a big enough header-pipe.. or a "cross-flow"... an SPI cylinder might work. It will be interesting to do some experimenting.

It's been too cold up here in New England to run engines outdoors.   We've had a few mild days here and there... but temps are still consistently in the 30's to 40's most days. I hope it warms up before the Speed Contest deadline.  

hey Rusty, yep I forgot, I enlarged plans for a Shoestring, but needed to redo the wing and didn't have paint (I did find a new jar of Cub yellow) I'm gonna build an early style mustang, I found two half empty cans of silver Ultracoat and a half can of clear...hopefully theres pressure in them as there over 10 years old.

I think/hope I should be good, get a couple hours tonight, Friday Sunday and Monday, photos are due Monday night at 11:59 pm...correct?

Mark Boesen wrote:I didn't know you were building a mustang, when did you decide this? I had to help jr. with the bike tonite so I didn't even touch it.

It's gonna be close!

DT 250?

Mark Boesen wrote:... photos are due Monday night at 11:59 pm...correct?

Correctamundo. Gonna work on mine after supper tonight. I spent the morning running the Fox and fiddling with the perpetual never-ending build of the Red(and white) menace.
Rusty

getback wrote:Ok : Sense's I need alittle help / got one of these working out pretty good on R,s.. but want hold a setting.. took the spring off added tubing to the needle , alittle better but still at about 3 1/2- 4 turns out is my best run I am getting but still keeps moving from set rpms , any suggestions ?   http://coxengines.ca/cox-.049-backplate-assembly.html  I know that's not a lot to go on but .....Thanks Eric

Double check that the needle isn't turning by itself. Maybe your reed is floating. Flip it over or try a new one. Mylar is the best in my experience. Check for leaks. make sure your screws aren't bottoming out before the backplate is snug. Sometimes the tapped crankcase holes don't have enough threads. Try two crankcase gaskets. Try another glow plug. Make sure the wind isn't moving and kinking the fuel line. Check for varnish in the cylinder. Make sure your fuel line is as short as possible. Try a filter. Post a pic of your setup.
Rusty

Try medium fuel line and a wire tie (twist tie, wire or string wrap) to hold it on the nipple. Problem is you may have to remove the engine to attach the fuel line.

Phil

Well, here it is.  It only took forever to finish.  With the rain lately it’s been shoot a color, wait a few days.  Shoot a color, wait a few days.  Repeat endlessly.  It’s four colors, flames, and a clear topcoat.  Final weight ready to fly is 4.85 ounces.  A little heavier than I wanted, but doable.  I know there’s debate whether a little heavier is better or not, but I wanted as light as possible.  I already know I’m not going to win, as I didn’t want to experiment with different props and heads and such, I just wanted to design and enter for the fun of it.  I was figuring that the lighter is it, the lower the wing loading, and the better the chances it will survive in one piece once the engine quits.  Once I get an official time and the contest is over, it’s getting re-engined with a PeeWee and put on shorter lines.







Since the fuel line takes a pretty sharp turn coming out of the tank, I took a spring from a Babe Bee and put it in the tank outlet tube to prevent the line from kinking.  Hopefully I have enough left thrust in the engine, but I didn’t want too much as I need all the drag reduction I can get.  Unfortunatly, I cannot now find my big while plastic spinner. My wife made me get a new desk, and my modelling stuff is boxed up and moved everywhere. I set the spinner aside for this project, and now I can't find it.

And Getback, I did the fuel tubing thing for a long time, but I find that I really like these.  I haven’t had an air leak yet:  http://coxengines.ca/cox-.049-.074-spray-bar-seal-10.html

The Finally Done Mark