CEF speed contest Design Discussions (2014)

Theo, if your looking for a decent takeoff use a lot of tip weight until you get used to it. If you traditionally use 1/4 oz., make it 1 oz. . My tip weight is externally applied so that I can add or subtract. If your plane is using a single gear wire, splay the wire over so that it automatically places the outboard tip on the ground. Ken

Theo,
This is my launch today. You'll notice I step back and pull the lines back to my ear to keep the lines tight.


Jim

Thank you for the video Jim. I see what you guys mean.

I am a bit afraid of this launching. I tried a .15 racer a while back and could not get it to take off. Everytime it came into me on launch.

This is going to be the hardest thing for me.

Thanks to all you guys for the help.

Need to get building on my Nemesis again this weekend.

Theo

Hi Kim. Thanks for the tip on the tip weight. I will most definately try that. I was also thinking of moving the leadouts back a bit, for a start. That should also make the nose want to go out, I think.

Thanks also to you Phil. I see from Jims video you have to pull a lot.

Theo

JPvelo wrote:Theo,
This is my launch today. You'll notice I step back and pull the lines back to my ear to keep the lines tight.


Jim

Aw, you teaser! Not even one lap!

Theo,
You are putting a lot of work into that nemesis, it should be a beautiful plane. Maybe you could quick build a practice plane of similar dimensions. Just a real simple similar span and chord, same stab size and distance from wing. Sand it, spray it with black rustoleum , and practice takeoff a before you risk the nemesis.

Jim

Thanks Jim. I hope it will end up to be decent enough. I am trying to do a nice job.

That is a great idea. I will need to try and do that. It should be quick to build a basic one. Then I can practice without a worry.

Theo

Theo Kleynhans wrote:Thank you for the video Jim. I see what you guys mean.

I am a bit afraid of this launching. I tried a .15 racer a while back and could not get it to take off. Everytime it came into me on launch.

This is going to be the hardest thing for me.

Thanks to all you guys for the help.

Need to get building on my Nemesis again this weekend.

Theo

Theo, since the first forum speed contest.. I discovered a few helpful tips that might ease your mind with launching these particular models. Being that the engines are limited to Cox "reed-valve" induction.. gives you the advantage of running your engine ("backwards") in a clock-wise rotation, while using a left-hand propeller. This has "two" advantages.. The first; is the torque-roll induced by the engine/prop pulls the model "outward" (assuming a counter-clockwise flight-circle) and away from the pilot. This creates instant line tension. The "second" advantage is requiring "much less" (if any at all..) outboard wing tip-weight.

You see.. most if not "all" model engines (other than the Cox reed-valve type) use a "rotary-valve" intake/induction design that runs "counter-clockwise".. and requires a right-hand propeller to be used... so that's what most of us are used to dealing with.. and thus; most props are right-hand props because of this. Here's another scenario.. If you "build" a speed model to fly in a "clock-wise" circle.. (bell-crank/lead-outs on the opposite side) while using the conventional rotation/right-hand propeller.. it will produce the same results. It all depends on if you're comfortable turning to the right.. instead of the left.

Build to keep lines tight. Use out thrust, and rudder offset. If you plan for it the rudder can be adjustable (on the ground) either with a linkage or a piece of soft metal. The out thrust can be adjusted with washers behind the motor. This means that as you trim out the model and gain skill you can gain performance.

Phil

Thank you for the information Roddie and Phil. I really appreciate all the help from everyone. I have learned a whle bunch on the forum. I am glad I got involved here.

The Nemesis is assembled. I did the hinge last night. I used the tubing and Piano wire like Mike, it felt really nice before installing it, but now installed it is a bit stiff. I will have to see how I can get it to move more easy.

Here she is:

Theo! Looking really sharpe man you guys have Really picked up the pace with looks and if it looks FAST it probably Is !! Eric

WOW! I went away for a few days and everyone got very busy! Looking good!

The "Space Duster " is coming along nicely:

How many are you making Jim?

Cribbs74 wrote:How many are you making Jim?

Just two, this one and the staggerwing. I have a set of corsair wings built that I am going to build into a Tee Dee/Norvel powered model.

Jim

Space Duster looks good !! that's a long wing 24" ?Eric

Hi Guys

I finished the Nemesis last night.

The plane came out at 58g (2.05oz) and with everything fitted it is ready to fly at 136g (4.8oz).






Now I just hope it flies!!

Theo

Very cool Theo!

Pick your best photo and post it on this thread to qualify:
https://www.coxengineforum.com/t7268-reed-speed-20-qualifying-photos

Very very nice....

I feel very ashamed of my lack of progress now. I just check the rules and should still have time to get last years unfinished model ready in time. Man, life is busy right now. I need to retire so I can fly and build more.

Me too Duke. I've been pretty scarce around here for the last month or so because this a busy time in my business, but I have been picking away at my race planes.

The Conquest Bearcat is painted and awaiting final finishing and assembly. The Red Baron Mustang is completed construction-wise, but I haven't even begun the finishing process. I'll try to post some pics this weekend.

I hope I can get at least one flight in, even if it's not with a full race motor, just so I can be in the show!

Mike

I ordered parts to get my duster from last year running on bladder. I think my real problems stem from fuel delivery failure.

Or cast cases are garbage. I got a solution for that too - build a second engine for bladder with a billet case!

Phil

By the way, what are you guys using for clear coat (assuming you are)? Is there anything that comes out of a rattle can that will hold up to 35% nitro? I've used Rustoleum on my stunters, but I only use 15% max in those.

I have a feeling this has been covered before somewhere, but haven't found a real answer so far.