CEF speed contest Design Discussions

crankbndr wrote:The H-1 looks fast even on paper, the wing span is wrong, it should read 25' in this configuration

I actually got to sit in the cockpit of the H-1 Racer that was built in Cottage Grove, OR. Man, sitting in the cockpit and looking out, that nose seemed to go on forever! I wish I could have flown those old racers back in the day. Hmmm...

The Day Dreaming Mark

Did you know the builder, that must have been cool to sit in the cockpit. The crash that destroyed the plane that killed the builder was because of a variable pitch prop malfunction.

http://vimeo.com/2745432

batjac wrote:I've got mine picked out.  I just have to figure out how to make the graphics for the sides.  I was gonna pass on this contest, as I been kinda poorly the last few weeks, but a challenge is a challenge.   I spent about an hour last night thinking about how I'd do it.  Soon's I finish the project I'm working on now, I'll draw it out and start cutting wood.  I think I'm gonna try something a little different with the engine this time.  If it works, I'll post build pics of the plane.  If it don't work, well, forget I ever made this post.

The Under Wraps Mark

Remember, you don't need a scale paint scheme for this contest. If you want to that would be great but it's not mandatory.

Jim

roddie wrote:

JPvelo wrote:Here's my first cut:

I think it was Roddie that said this already but man these things are small. I think we'll see some good speeds with this!

Jim

Jim, that cowl is sweeeet! (my cowl choice...   )  

Yea... this challenge really makes you realize how big your fingers (and tools) are. I'm going to use a 6" machinist rule for laying-out the remainder of the parts...

That cowl unfortunately no longer exist. I tried soaking it in acetone to remove the paint. Not only did it remove the paint, it removed the cowl as well.

Jim

That's funny... 

Sorry

Cribbs74 wrote:That's funny... 

Sorry

That cowling was from the ill fated staggerwing series of planes so it was probably cursed anyway. Good riddance to bad rubbish.

Jim

Yesterday, I undusted this little book I bought a few years ago in the UK. The original edition dates from 1941 and helps to recognise friendly and hostile aircraft.



It's got profile and plan views of fighters, bombers, trainers, seaplanes... and with a brief description. Aircraft are grouped in chapters according to single or multi engine, high wing, low wing etc.



Lieven

Nice legs... it's gonna be hard to replicate those on my model  

roddie wrote:Nice legs... it's gonna be hard to replicate those on my model  

Remember Roddie landing gear is not required to be in the scale location. I'm struggling with that idea on my corsair, I want it in the scale location but I don't want to add five hours to the build!

Jim

It presents a challenge to me... I'm always up for that. My planned gear will weigh a little more... but I don't think that building these little speed ships "light" is in anyone's best interest; when flying these models in an 84' dia. circle.

Line-drag alone is something that needs to be considered. The plane is gonna unwind; well before the 10th lap... so isn't it better to have some weight out there, along with minimum control-throws, to maintain the fastest level flight?

Scale-like gear will also track better at R.O.G. making for a smooth climb-out. Anything to try to avert a mishap... I'm trying to think the flight through, and all the forces that the model may be subjected to... I keep wanting to build engine/rudder offset into the fuse... but it's only advantageous to a Stunt model... and this would only induce drag in a speed ship. One could probably gain speed, with slight inboard offsets, on a properly weighted model.

Nice work Roddie, I anticipate making some progress this week.

Jim

crankbndr wrote:Did you know the builder, that must have been cool to sit in the cockpit. The crash that destroyed the plane that killed the builder was because of a variable pitch prop malfunction.
http://vimeo.com/2745432

I flew down to Cottage Grove for a biplane fly-in one weekend, and the owner showed off his H-1 to the attendees. He was gracious enough to let me sit in the cockpit to see what it was like in one of those old race planes. Golden Age of Aviation, indeed.

The "After My Time" Mark

Food for thought:
http://www.taichiunlimiteddrawings.com

JPvelo wrote:Food for thought:
http://www.taichiunlimiteddrawings.com

Great resource Jim! Thank You!

Great site, Jim. A few days ago, I looked at pictures of the Tsunami, also mentioned on this site.



Below the CL version: 1 picture, 2 birds



Lieven

Great site Jim. Although, I might have to change my plans now. THANKS!

I shot white onto mine today.

I am trying Minwax polycrylic as a sealer/base. Put on 2 coats, washed with denatured alcohol and a "scrubby" sponge (surprisingly effective at removing the excess polycrylic, 24 hours old) However I probably should have put another coat or 2 on and stripped it down again.

1 coat grey primer, sanded, 1 coat white. In a couple hours it will go to the basement to cure.

I think the elevator is getting Monokote as an expedient.

Phil

JPvelo wrote:

roddie wrote:Nice legs... it's gonna be hard to replicate those on my model  

Remember Roddie landing gear is not required to be in the scale location. I'm struggling with that idea on my corsair, I want it in the scale location but I don't want to add five hours to the build!

Jim

Jim... you were close to the mark on the "5 hour" extended build-time on scale-like gear/placement. Since I enjoy building... I went for it.

(edit) The wheels; I made years ago... on a CNC router. They are 15/16" in dia. and 3/16" thick (5/32" foam faced both sides with .015" styrene.) with 1/8" axle holes that need to be bushed for .062" dia. m.w. axles. #15 O-Rings make the perfect tire... stretching on to the wheel and compressing the foam and seating against the styrene facers. Finish size is 1.125" dia. and the O-Ring is .125" dia. (tire width) I'll have some weights on the gear components in a little while.

My "scale-like" gear design-weight; as compared to a stk. Cox PT-19's gear.

in ounces...




and in grams...




Gear weight is less paint (on the .020" polycarbonate gear-doors) Struts are .062" music-wire, set in "cherry" hardwood blocks that attach to the underside hardwood strip leading-edge/spar, with #2 wood screws/washers, for a rigid mounting... that can be removed if needed. Wheel retainers are the old "twist-on" spring type that fit 1/16" dia. music-wire. The wheel axle-holes were bushed with 1/8" and 3/32" Aluminum tubing.

pkrankow wrote:I shot white onto mine today.  

I am trying Minwax polycrylic as a sealer/base.  Put on 2 coats, washed with denatured alcohol and a "scrubby" sponge (surprisingly effective at removing the excess polycrylic, 24 hours old)  However I probably should have put another coat or 2 on and stripped it down again.

1 coat grey primer, sanded, 1 coat white.  In a couple hours it will go to the basement to cure.

I think the elevator is getting Monokote as an expedient.

Phil

I'm curious to see how that finish comes out, I've been wanting to try it. Did you get before and after weights?

Jim

roddie wrote:

JPvelo wrote:

roddie wrote:Nice legs... it's gonna be hard to replicate those on my model  

Remember Roddie landing gear is not required to be in the scale location. I'm struggling with that idea on my corsair, I want it in the scale location but I don't want to add five hours to the build!

Jim

Jim... you were close to the mark on the "5 hour" extended build-time on scale-like gear/placement. Since I enjoy building... I went for it.

(edit) The wheels; I made years ago... on a CNC router. They are 15/16" in dia. and 3/16" thick (5/32" foam faced both sides with .015" styrene.) with 1/8" axle holes that need to be bushed for .062" dia. m.w. axles. #15 O-Rings make the perfect tire... stretching on to the wheel and compressing the foam and seating against the styrene facers. Finish size is 1.125" dia. and the O-Ring is .125" dia. (tire width) I'll have some weights on the gear components in a little while.

I decided yo go with a non scale gear on the corsair for simplicity. I also don't want to stress a multi piece wing wit a landing gear. Plus making a profile corsair reduces the landing gear track by two inches, pretty tippy on a plane that will touchdown like a lawn dart.

Jim

I'm hoping that good balancing and an ample elevator will permit non-eventful high-speed landings. This gear arrangement places the struts at right angles to the wing, on the leading edge and raked 10 deg. forward. Shock-loads should theoretically be distributed more "linear" to improve tracking. By comparison; an inverted "V" (music-wire) main-gear will twist both struts off-axis, with either or both wheels being loaded.

Maybe I'll end up with the well-known "Spitfire's" gear issues; when being modeled as a flying scale subject. I hope not...