CEF speed contest Design Discussions

JPvelo wrote:Mike,
Don't listen to Rusty.  He is realising he may need an air freshener after smelling the nitro as his mustang chases behind my corsair.   
Yes it is the sig cowling, I will measure it tomorrow. I would just order the whole staggerwing kit as it flys great and sig makes you order $35 dollars worth of product to avoid $15 in shipping. Don't even get me started on that.

Jim

Aw man, I thought you said it was a Lysol cap. Sorry about that. Didn't want to insinuate you were flying garbage.
  
Somebody had a Lysol cap cowl back in the early pages.

$35 bucks now! Damn, I could work with the old $25 but that's robbery. They know we need them. Greedy suckers. Lucky for me, my club has a Brodak dealer as a member. But he lives an hour up the interstate from me. He does have a CL field on his property though.
Rusty

This is how far I am at the moment. I choppoed off 20mm from the nose because of the well known problem. I made te landing gear near scale and I have problems keeping the nose up. I'll have to make a bolted on steel control horn, I think. Still some work to do.





Lieven

Looks great Lieven!

Here you go Mike:

Nice work Lieven I really like that cowel and the working feature , a lot of pride there I am sure !!  

I like it Lieven!!!!

Here is where I am at with mine. I think I may actually make the deadline.

Hats off for the biplane Ron! Too cool. I think I'll go one next year.

Jim

Thanks Jim,

That's it for pics until it's done. I am doing something really different on the finish. It will either look really cool or really bad. Either way it will fly!

Ron

JPvelo wrote:Here you go Mike:

Thanks Jim,
Its a little small but I can work it out. Gonna put a couple on order. My experience with the Beechcraft many years was not so great. I suppose I may revisit it someday but am gonna order a Deweybird instead. Its actually "scale". Its what Jim Dewey called a "Super" Cosmic Wind. He raced it from '61-'67. Search aircraft N3Y on google or bing. Worse comes to worse I can use it for an official time but I'm gonna throw it together and  use it as a trainer to introduce myself to C\L speed. I'm not entirely confident I can spin that fast these days.

I built a Dewey for my Father-in-Law (now ex) for Christmas one year. I never saw an old mans eyes light up like that when he opened it. We spent the afternoon flying the Dewey and my beat up ole Skyray. He had flown in his youth but gave it up for the Airforce/College/Family but he was like a duck to water. What fun!

Mike

Hey Mike, Sorry I'm late with this... I hadn't watched the thread for a couple of days... and it looks like I missed a LOT!   

I'm the one with the cowl from an aerosol can. It came from an Airwick "Freshmatic Ultra" (automatic air-freshener) replacement cartridge. It has a larger 2.5" i.d. which may work out for you. A nice feature is a shoulder/ridge on the inside about 1/4" in from the edge.. which acts as a "stop" for the nose and some support-tabs that I made.

The cap does have a decorative "swirl" molded into it though, that you may not care for. It didn't bother me for my model.




I made four .005" sheet-Brass support-tabs extending off my engine mount, that are even with the nose; where it enters the cowl. This gives some radial support to it.. and the cap's shoulder helps keep it all centered. The cowl fastens using two short #2 wood screws, top/bottom.

Cribbs74 wrote:

Here is where I am at with mine. I think I may actually make the deadline.

Very good choice Ron. I wondered what those holes were in the fuse. They seemed to have been cut at random. But when I saw a picture of the side of the real thing, I found out. You're gonna outline the cockpit I presume. Oh and I'm looking forward to see those wheel pants too!! All 3 of them!!     or maybe not  


(picture stolen from RCG)

Lieven

I painted the wheels and fixed them onto the landing gear. As shaft, I used M2.5 countersunk bolts that I bolted onto the landing gear. On both sides of each wheel, I put a 3mm brass washer and to lock all that, instead of using a nut and counter nut, I used a part of an empty ink tube of a Bic pen. It screws onto the thread and stays there. Make sure you cut the bolt to size with a cutting pliers after mounting. That gives an extra lock for the plastic tube.





These are the worst pens ever made. That's why in offices, the employees get them for free. I think they cost nothing and they never write properly. They're only good to throw in the bin... and what goes in the bin, comes back out for modeling.

Lieven

OVERLORD wrote:I painted the wheels and fixed them onto the landing gear. As shaft, I used M2.5 countersunk bolts that I bolted onto the landing gear. On both sides of each wheel, I put a 3mm brass washer and to lock all that, instead of using a nut and counter nut, I used a part of an empty ink tube of a Bic pen. It screws onto the thread and stays there. Make sure you cut the bolt to size with a cutting pliers after mounting. That gives an extra lock for the plastic tube.



Lieven

Lieven, your model is looking impeccably beautiful!!!!!

I see a couple of contenders for the beauty contest!

Who can tell us about the reason for the split elevator on some models with only the inboard side applying control?

RknRusty wrote:
Who can tell us about the reason for the split elevator on some models with only the inboard side applying control?

How about a "guess"?.. I would imagine that not much elev. area is needed for one thing.. and having it hinged inboard I'm guessing is more effective in maintaining line tension.. because deflection would tend to yaw the model's nose outward and it's tail inward.

Check out this page if you haven't already.. VERY COOL STUFF!!! (and you can blame me for ruining your time-management skills)

http://www.angelfire.com/fl/yspeed/

roddie wrote:

RknRusty wrote:
Who can tell us about the reason for the split elevator on some models with only the inboard side applying control?

How about a "guess"?.. I would imagine that not much elev. area is needed for one thing.. and having it hinged inboard I'm guessing is more effective in maintaining line tension.. because deflection would tend to yaw the model's nose outward and it's tail inward.

Hi Roddie, your Yspeed link looks good. I'll peruse it tonight and look for some elevator info too. I've tried to picture what's happening with only one side deflecting, and see it affecting yaw and roll at the same time. It seems like Up would roll the model in, while drag would yaw it in, both bad things. Down would roll the model out, while drag would again yaw the model in. I'll read more before I make my control surfaces.
Rusty

RknRusty wrote:I see a couple of contenders for the beauty contest!

Who can tell us about the reason for the split elevator on some models with only the inboard side applying control?

I think there are two main reasons for the half elevator. Speed planes are not doing stunt, you don't need major attitude correction. The goal is to go straight and level. On a properly trimmed model only minor adjustments are necessary. The second reason is ease of assembly. These are just my best guesses.

Now check this out:

A guy named Ed in my club showed up at the meeting with this beauty last week. Completely home fabricated, jet engine and all. He said the elevator is canted up so that on takeoff it acts as a rudder pointing the nose out and keeping the lines tight until it gets up to speed. Not really relevant to our conversation but really cool!

Jim

JPvelo wrote:

RknRusty wrote:I see a couple of contenders for the beauty contest!

Who can tell us about the reason for the split elevator on some models with only the inboard side applying control?

I think there are two main reasons for the half elevator. Speed planes are not doing stunt, you don't need major attitude correction. The goal is to go straight and level. On a properly trimmed model only minor adjustments are necessary. The second reason is ease of assembly. These are just my best guesses.

Now check this out:

A guy named Ed in my club showed up at the meeting with this beauty last week. Completely home fabricated, jet engine and all. He said the elevator is canted up so that on takeoff it acts as a rudder pointing the nose out and keeping the lines tight until it gets up to speed. Not really relevant to our conversation but really cool!

Jim

I had heard that you start those pulse-jets with a tire-pump and ignition-coil/battery connected to the spark plug. Does it stay running when you disconnect the coil-lead? Some run on gasoline or Coleman fuel. They are DEAFENING LOUD!!  

Nice reedy.  
There are many youtubes of these things running, and flying.

Phil

I made one more tank to try. This one is tall/thin and works out to 6.15cc's capacity.


It measures .250" wide x 1" tall x 1.5" long.


uni-flow venting like the others I made.





The paint's gonna' be tacky on this thing come the 31st... if I don't get my butt in gear soon!!!

Well, parts are starting to trickle in for my build. My late discovery/participation of this challenge is starting to hit home. I'm gonna give 'er a shot to get finished but....

I need to get some flying lines. I searched around and found you guys like Spectra and such in the lighter 10-15-20 weights but dont see what weight line I should use for speed flying.

Mike

Hi Mike
Don't worry, I'm just getting started too. Maybe we won't have time enough to overthink it into a kludge.  
I think I'll try some of the 10 pound line. I have some .008 steel too, but have never flown 1/2A on steel, so I don't know which is best. I'd say for those of us that are raw novices at speed... like me, this is the least of our problems, so just get what you think you can work with the easiest.
Rusty