CEF speed contest Design Discussions

RknRusty wrote: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, can work with the easiest.
Rusty

I agree, lack of time solves a lot of decisions. I just ordered a roll of 10 and 15 pound spectra off Amazon along with some other items I needed. One of those hopefully will work. I'd try to get some metal lines in but I'm tired of ordering stuff. Its sobering how much you need for a simple 1/2A when starting completely from scratch.

Mike

Some Vaseline on a toothpick might have worked too.
Rusty

Looks good Roddie!

  Looking good there Roddie ,Man you put that together quick    Got mine painted yesterday took about an 1.5 hour outside I am happy with it though have to do alittle touch up here and there , PIC not ....Eric 

Little sunday job: I added some tail lettering. Hopefully, the varnish will not spoil it.



Lieven

Ok,

Here it is minus landing gear and control linkage. It weighs 4.6oz as it sits. Not sure if low weight is desirable or not?

roddie wrote:...If having lightweight is an advantage... I'm in trouble there. I'm a full 2oz. heavier than you.. and one ounce heavier than either of Jim's models. I built my Bearcat with it's proportions by "eye" and it's got a lot of wing and fuse area. The 17" span wing is just over 70 squares with a 6" root chord, tapering down to 2" at the tips.. no dihedral and is dead-flat 1/8" sheet balsa. The 1/4" balsa sheet fuse is almost 3.5" tall between the belly and the top of the canopy. I'm surprised that it doesn't weigh more than it does.

Have you figured outboard wingtip weight in yet? I didn't see a tip-weight in your photo.. unless you used a heavier outboard wing strut? That would be a neat way to accomplish it on a bipe. I was thinking .010" Brass sheet.

Here's where most of us guys are out of our area. At first I was thinking radically light. a butterfly with an engine. But I was overlooking the advantage of whipping up inertia for several reasons, one being penetrating the wind, and also resisting floating. That second part also speaks to the wing area, of which less is best. A flying knife is probably what we want. I think I have a good wing if it's not too wide at the root, about 47 squares and 2" tips. I don't know for sure, but it seems like more tip weight might be helpful here.

I haven't got but a couple of hours into this thing. My wing location is adjustable like those toy gliders we played with decades ago, and will be the last thing glued in place. It's been sitting ignored for two weeks now, so time is rushing up on me.

I'm going to laminate the stab/elevator to encase a gapless hinge. What you see here weighs about nothing. It may be too light.

C'mon Rusty, you have plenty of time. A full week from today if I'm not mistaken!

Jim

JPvelo wrote:C'mon Rusty, you have plenty of time. A full week from today if I'm not mistaken!

Jim

Oh don't worry, I'll get it in under the wire. Even if it kills me, tomorrow is the last day I'm working on the Yak. That was supposed to be yesterday but nothing I did worked. Just one of those days. Tomorrow is gonna be a great day!

Rusty

hey Rusty ( and everybody) i'm in the same boat, dragging my feet on this project as well, now i'm thinking since I got the wing and fuselage cut for a mustang to just go ahead and finish it, forget about the shoestring. i'm off Tuesday and its only gonna hit 27, so I think i'll pass on disc golf and do some building...I remember as a kid we could slap together a 1/2a kit in an afternoon (it probably looked like it) so I really think 2-3 evenings should be good.

roddie wrote:

Cribbs74 wrote:Ok,

Here it is minus landing gear and control linkage. It weighs 4.6oz as it sits. Not sure if low weight is desirable or not?

Nice Ron!!! and also nice to see a hard-tank on it! If having lightweight is an advantage... I'm in trouble there. I'm a full 2oz. heavier than you.. and one ounce heavier than either of Jim's models. I built my Bearcat with it's proportions by "eye" and it's got a lot of wing and fuse area. The 17" span wing is just over 70 squares with a 6" root chord, tapering down to 2" at the tips.. no dihedral and is dead-flat 1/8" sheet balsa. The 1/4" balsa sheet fuse is almost 3.5" tall between the belly and the top of the canopy. I'm surprised that it doesn't weigh more than it does.

Have you figured outboard wingtip weight in yet? I didn't see a tip-weight in your photo.. unless you used a heavier outboard wing strut? That would be a neat way to accomplish it on a bipe. I was thinking .010" Brass sheet.

I plan on using a penny as tip weight.

As to the hard tank, I figured this is nothing like stunt so I wasn't too concerned about all the fuel delivery issues you experience in PA. Hopefully it works for 10 laps.

Ron

Mark Boesen wrote:hey Rusty ( and everybody) i'm in the same boat, dragging my feet on this project as well, now i'm thinking since I got the wing and fuselage cut for a mustang to just go ahead and finish it, forget about the shoestring. i'm off Tuesday and its only gonna hit 27, so I think i'll pass on disc golf and do some building...I remember as a kid we could slap together a 1/2a kit in an afternoon (it probably looked like it) so I really think 2-3 evenings should be good.

Yes! Can Do! Will Do. We are master balsa builders. If I have to bolt a motor on a stick, I'll make the finish line!

yep, it's go time!

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.

Hey that's pretty cool. See, it looks fine after all.
Rusty

Thanks Rusty,

The LG wheels and control rod bumped the weight to 5.1 oz.

Looking good Ron! I put a tail skid on both of mine and they got knocked off on the first landing. I have since switched to a small blob of epoxy.


Jim

JPvelo wrote:Looking good Ron! I put a tail skid on both of mine and they got knocked off on the first landing. I have since switched to a small blob of epoxy.


Jim

Funny you should mention that. The landing is really freaking me out. I am good with the slow ascend and overall speed, but that high speed landing is going to be a bear. I am glad the landing is after the timed 10 laps. As long as it's fast I only need to do it once.  

I plan on pinning the skid into the fuse so hopefully is won't snap off.

Thanks Roddie,

I think those wheels are 1" Perfect streamline wheels. I like them too as they remind me of Moon wheels from the 60's with those solid aluminum centers.

I plan on doing my skid much like you suggested