CEF speed contest Design Discussions

....Rusty it took a dive like it was going for a outside loop if , i was up at a good 90 degrees from level arm when i put alittle down in it .......Roddie i feel ur pain ..ther saying next year sounds good to me Getback's second attempt , Iam not done another glue job ,I  want to find ouy why it is taking that down so quickly and want recover as it takes off well  Maybe I was not up to speed for an altitude change?

I followed your advice and with Jim's encouragements in mind, I gave it another go yesterday with the assistance of my neighbour Jacques. I left off the engine cowl and the ram air intake. That leaves me with less parts to repair afterwards. I also mounted a 3 bladed 5x3 LH prop. The centre spot was marked with orange fluorescent paint. I managed to fly a few laps but the plane hit the ground each time. I broke the outboard landing gear during one landing but decided to continue as that didn't matter much.



Then the inboard landing gear with the belcrank mount broke. I glued it back in place with CA glue and I replaced the prop by a 2 blade 4.75x4 RH one. I wrapped some lead strip around the throttle needle to improve stability. Again some laps of flying were achieved but it came down again.



After the last take off, I remember seeing the outboard wing lift and the plane took a serious dive, leaving me with multiple parts: time for a drink.



I hope you all appreciated my 24h of Le Mans style start. Also, I was supported by my loyal fan club and a cheerful public. Some moments came out funny, looking afterwards: before one take off, I could find my handle in the grass.



It was not a total failure as the thing did fly. There are some changes, improvements and modifications to be made for next year's model.

It was a great experience. Thanks to all of you.

Lieven

Lieven,
You receive the "Best Flying Site" award. That is just beautiful. I made my videos in a parking lot across the canal from a water treatment facility.

Jim

Sorry to see that Lieven, sure you can repair though (that grass looked a lot softer that it was after I saw were u landed?) I,ve patched mine one and going for another round soon    Getback

Sorry to see that Lieven, truly I am. I have a couple ideas. Sending you a PM

getback wrote:

....Rusty it took a dive like it was going for a outside loop if , i was up at a good 90 degrees from level arm when i put alittle down in it .......

Roddie i feel ur pain ..ther saying next year sounds good to me Getback's second attempt , Iam not done another glue job ,I  want to find ouy why it is taking that down so quickly and want recover as it takes off well  Maybe I was not up to speed for an altitude change?

Hey Eric, a couple observations; Your engine sounded real good! I'll bet you were getting over 20K out of it! Also; I saved EVERY photo of EVERYONE'S build-stages, in a folder on my PC.. Both of our models I believe are the only two that have a full-span hinged elevator, which means twice the deflected surface area than the other contestants who chose to go with a traditional "speed" elevator. On my Rare-Bear I used a #237 Dubro control-horn  (longer than the 1/2a type) and put the push-rod in the outer-most hole that I could; without it rubbing on the wing's trailing-edge. This is exactly 15/16" down from the hinge-line, greatly de-sensitizing the elevator.



I also have slightly more "up" throw than down.. (I figured this might be needed on mine)

Are your controls set to the least sensitive? How about your handle's line-spacing? One of the things I needed to do, was to match mine with my bell-crank/lead-out spacing.. which I did. These things all figure-in to your control inputs at the handle, out to the airplane.



While I was at it; I drilled a hole-set for a 3" spacing too. This "Sagan" handle originally had spacing for 2-1/8" and 4". Now it has 1-1/8", 2-1/8", 3" and 4". Maybe if you try less sensitive control settings, you'll have better luck? I think that models this small and having a very short O/A length.. are real sensitive to pitch variation.

FWIW, mine has a full span hinge. I laminated a piece of fabric between two 1/16" sheets to form the stab and elevator, so there's no air gap. I positioned the hinge joint a bit too narrowly so I only get about 20 deg. deflection.
Rusty

My elevator hinge has a huge gap in it. I wasn't concerned as I wasn't wanting this thing to be quick on controls. Even with the gap it was very responsive as evidenced in the video below. It was windy and I had to dive into the wind a little to keep up speed. No this is not my entry video.

should have been about 19,000 give or take Roddie, I was very pleased at the way it was running. I checked the lead outs vers. the handle , and I will need to do some changing before I try again..... c cant make it perfect but get a lot closer..   I am in the center hole think ill move to the outter ...... this should be ok.  Thanks for bringing that to my attention, it is in the hospital now glue setting up      Ron watched the video man that plane rolls a lot better than mine    Least you got some rounds in!!Getback out 

Leadouts in the wing tip mean nothing for control rate. It is bell crank vs handle spacing you are interested in.

Phil

pkrankow wrote:Leadouts in the wing tip mean nothing for control rate.  It is bell crank vs handle spacing you are interested in.

Phil

Yes Phil.. good to clarify that. My lead-outs have the same exact 1-1/8" spacing as my bell-crank. They are raked-back slightly at the wing-tip (2-3 degrees) per Paul G's advice, to help with line tension where there's "zero" thrust/rudder offset.

Eric, if you swap to the "inner-hole" on your bell-crank, it will also lessen sensitivity, along with the "outer-hole" on the horn.

Sorry I missed this, But I did get that figured out moved both ..bellcrank inner ..control horn to the outer that changed the throw a lot ! I think maybe I can handle it now . Thanks I guess I was just not thinking straight   Have not got the chance to fly it yet but am looking forward to it  I would still like to see what the time will be  Looking for another build for the next race I am thinking Pylon formula 1 ?? Did you get yours in the air I may have missed it , have been pretty busy here but no FUN as I would wish   Getback

Hi guys! My name is Mike Mulligan, I'm new around here and came over from the Stunthangar forums. I usually fly stunt but the Reed Speed contest sounded like WAY too much fun to pass up! Like most of you, I suppose, I grew up with Cox engines in all of my planes (and cars, and boats...) and still have a soft spot for 'em.

I got pretty excited about this thing when Jim posted about it over at Stunthangar and started sketching out a couple of designs almost immediately. I might have to do a few planes since I can't decide which one I like best. They certainly are economical material-wise, especially compared to a typical stunt ship! So far my ideas involve another Bearcat and Corsair, though the Bearcat will be more like Greenameyer's 'Conquest 1' than Rare Bear. I'm also thinking a Scorceress-type biplane would be fun!

I hope I haven't missed something that was obvious, but I have read through the rules and through this thread and I'm still a little confused on landing gear. The rules say that an airplane that had retractable gear can omit the gear all together. But reading through here it seems to be a requirement to ROG for an official flight, but I didn't see that in the rules. If it is a matter of ROG would a drop-off gear or dolly be permitted?  

Given the option I would omit the gear for a couple of obvious reasons, not the least of which is the weight and drag advantage, but I fly over grass and tend to think the airplane might survive a little longer belly flopping in the grass rather than tripping over it's gear and tumbling. All of the planes I've seen so far have had gear, so I'm assuming there is an agreement to that effect. That, or I completely missed something that is really obvious in the rules (Most likely, I expect!).

I don't mind either way, I just wanted to to clear that in my mind before the lumber hacking begins...

Thanks for doing this contest and thanks for having me!

Mike

Mike,

Welcome over. Glad to have you here. The reason you see all the planes with gear on this thread is because the firsst iteration of the Reed Speed contest mandated R.O.G. for official flights. But, for many of us who fly alone or off of rough fields, R.O.G. is not a great option. So Jim was nice enough to change the rules for the second contest to eliminate the R.O.G. requirement. That'll make it easier and probably up the participation greatly for the next go round.

The Merry Mark

Thanks for the clarification Mark, much appreciated. A belly flopper it is, I suppose...

Love the Sea Fury, by the way.

Mike

Hi Mike, I was hoping you'd show up over here, glad you joined us. We try to do all sorts of different activities to ward off the boredom. You'll recognize a few names from SH too.
Rusty

For those who may be wanting or needing a plastic radial cowl but don't want to buy one from Sig, check the local Wal-Mart or supermarket for a drink called Sparkling Ice. It is a flavored fizzy water that comes in clear plastic bottles that are 2.33" in diameter and have a great shape for a cowl. The drinks aren't bad either!

Welcome aboard Mike!

Jim

Thanks for the welcome guys. This is really a great idea for a contest and one that fits well into my schedule right now. Nothing like having a nice little low-key, just for fun competition to take too seriously!

This is the real Conquest 1 Bearcat that is the basis for my design. Still massaging the dimensions, but so far it is coming along pretty well. Hope to start cutting some wood tonight, Lord willin' and the river don't rise...




A few paint options:







And my favorite picture. What a beast!


And a reedy should create a pretty scale oily exhaust smear down the side!

Thanks again guys,

Mike

Man, Mike's got it bad. Looks like the ante is going up this time around.  
I'm sure I'll do my usual last hour speed build. It barely got the job done the first time, but I better get some projects moving.
Rusty

I am knee deep in my speed build. I am not posting pics this time though. I learned from the last round that a 20K plus engine doesn't amount to a hill of beans if the airframe is slag.   

Cribbs74 wrote:I am knee deep in my speed build. I am not posting pics this time though. I learned from the last round that a 20K plus engine doesn't amount to a hill of beans if the airframe is slag.   

I'm the other way. I think I had a good airframe and need more power. I'm probably going to use the same mustang with some changes. Maybe some engine work is in order. Maybe I can slide that wing another 1/2" forward so it'll float and glide better. And rethink my elevator.

I got some new Tee Dee P/C sets from Bernie today and they have extremely good fits. I'm impressed. They do feel like some light lapping needs to be done in the exhaust port area where the bar was removed and the bottom exhaust deck was lowered.
Rusty

The best advice I can give is after you get your motor screaming test every prop you can get your hands on. There's a 5mph spread in this photo. If I could just remember which one was the winner....