Falco250

Some explanations on flood off:

http://www.rcuniverse.com/forum/m_75...tm.htm#7593679

http://freeflight.org/phpBB3/viewtopic.php?f=1&t=541

http://freeflight.org/phpBB3/viewtopic.php?f=13&t=42

Falco250

Max_Power

Thanks Falco250! That gives me some sort of idea.....I don't think I need to mess with it for now. CP...I've got the frame started (is it really this simple?) But mine is a tad smaller as for some reason my mind "remembered" 23" instead of 25" wingspan when I was sitting at my bench. So is the body made of formers and sheet? Sorry to need so much handholding, But I figure you've got this down. Would it be crazy to glue a piece of 3/8 LE stock to the leading edges instead of sanding? Thanks in advance, Todd

combatpigg

My Feedback: (3)

Looking good Todd..! Don't forget to cross drill key places [intersections] where you can force in round toothpicks to help make some of those glue joints stronger.
Nobody from Heaven came to me with how this plane should be built, so by all means use your own ideas if you see ways to improve this airframe. I like the idea of adding leading edge or half round stock. This plane has enough wing area to give you flexibility to splurge on what you want to add to it.
Just be judicious about it. Sometimes [actually most of the time] extra work is the best way to make a plane both strong and light. Having a strong perimeter frame is very important and once you see these planes in action you will get a sense of where you went too far or didn't do enough as far as strength goes.
It's great to see you so far along with this project, I think deltas are a great way to see quick returns on your labor in exchange for fun.

Max_Power

I wouldn't have thought of the toothpick idea CP!

I stared at the plane last night for a while and decided to do this: I measured dowl the spar 2 inches down and made a cut to cut the tip of the nose off. Then I took the piece I had cut out and flipped it over, Glued it back in, And cut a piece of 1/4 plywood with a opening in the middle for a norvel/wasp to fit in...and that would fit into the square hole now in the nose.

I plan to dremel out the back corners of the motor slot (for the radial ring) and glue a hardwood block on top and bottom behind the engine area so that the Fora can be swapped with the "testing wasp/norvel" with little effort once I get things dialed in. I also glued on 3/8 leading edge strips. I'm assuming 15% back from the MAC is a good starting point for looking for a CG? P.S. Sorry If I'm hi-jacking your thread. Todd

combatpigg

My Feedback: (3)

As for the CG, that's the way to go.
Your idea to use a flat plywood engine plate simplifies using a Norvel...but if you study the photo of the side view of this plane, I think your engine will be too far back.
I'd just go with the circular plywood firewall and use a plastic engine mount for your Norvel, then it's a quick swap to the Fora.

Since you are using a slightly smaller airframe, your engine placement might be OK...?

Max_Power

I'm guessing as long as I can balance it will be OK? Perhaps with the Fora I can use a hardwood block that just bolts where the norvie would mount that the Fora hangs off the front of? At least these airframes seem simple enough that if I need to redesign a bit it won't be a problem. Todd

combatpigg

My Feedback: (3)

Here is my updated controls. I moved the ball links to the middle hole on the servo arm for finer control and replaced the original plywood control horns with taller plastic ones. The fuselage sides needed to be hogged out so the ball links wouldn't bind against at full servo travel.
With the linkage adjustment the servos are running at 100% travel and the channel 1 servo [banking] is set for 50%. Channel 2 [pitch control] is set for 100%. This gives me 1/8" throw for banking and about 1/4" for pitch. Not 3D throws, but enough to battle crosswinds when gliding deadstick.
Next step is to order some new batteries. All my little NIMH are shot. I'm thinking about ordering AAA low discharge type cells from Hobby King. I think they claim 800 mah and up to 2 amps of continuous discharge. I don't think 2 HS81s would ever pull half that much..but it might pay to rig up a test to see for sure what the worst case amperage would be if a linkage got jambed up.

Max_Power

So you mentioned that your trailing edge is tapered to a smooth transition into 1/8 elevons. Is that just to make the transition, or does the wing need to be that thin on the trailing edge? If one wanted to use trailing edge stock that was 5/16 or so at the thick side for the elevons would the wing need to be thinned that much? Or would that just be a bad idea?

combatpigg

My Feedback: (3)

I believe that it's just a basic part of model building to shape the wood to give us what we want.
1/8" is as thick as I'd go for 1/2A elevons and for the best performance I wouldn't want much of a step in thickness at the hinge line. A tiny step might contribute to smoothness around neutral because it aerodynamically shields the flap. Kind of like built in exponential.
I have a marking tool to draw center lines in the hinge gap and this acts as a guide as I shave both sides of the airframe to a nice gradual taper. Start out with 50 grit on a long sanding block and you will cut through it quickly. Beware of going overboard with the heavy grit. Take a few swipes then check your progress often.

Max_Power

I'm watching with interest to see this thing go CP. I've got most of mine done...need to redo some covering as I'm still working on that skill but I'm pretty happy with it otherwise. I'm really interested to see how your model flys with the Cyclon. On a side note, what do you think about the GloBee style filament Nelson plugs in the Cyclon/Fora? Todd

combatpigg

My Feedback: (3)

The flat wound plugs take a lot of juice to light..that's about all I know of them. I just use the standard Nelson plugs and 10-15% nitro most of the time.

combatpigg

My Feedback: (3)

http://youtu.be/rkWK7CLYefs

It was 62 degrees yesterday, perfect.
First launch the controls were too sensitive and I pancaked it into the grass.
Elevons are now set with 1/8" from center for roll control and 3/16" for pitch.
The APC 4.75x4 pylon prop pulled this model better than the 4.2x4.
It handles very good, not extremely fast, but it's a very race-able plane that you can land at your feet.

ProBroJoe

Nice! Looks like your cameraman was in the groove too!

combatpigg

My Feedback: (3)

Camera man has to build up his neck muscles...!
It took 90 minutes to upload 30 seconds........[:@]

Speed was 112 mph...which is about as fast as a good TD .049 powered SWR

vicman

My Feedback: (10)

The field looks mowed this time.
Plane looks pretty good, I think the Corsair was a little faster

combatpigg

My Feedback: (3)

Vic, yeah....the Corsair and the Magnum run in the 120's.
Bear in mind, this delta was my first ever experience with the Fora .049 and way back then it seemed like a pretty hot enchilada..!

Revisiting this plane taught me that I don't know as much as I think I do about preliminary set up. It needed the roll control dialed down quite a bit from where it was at the first launch.
The other thing is that the Cyclon .061 handles a APC 4.75x4 prop just fine. It sounded good and showed no signs of over heating or plug failure.

vicman

My Feedback: (10)

It sounded pretty sweet.
Since I started flying fast planes on a planned course, the value of not having too much throw has been a big lesson. Thankfully there are triple rates on my Tx.[X(]
I smiled when I saw those huge loops at take off. You are the only guy I know who trims one out that way.

combatpigg

My Feedback: (3)

Any launch that grabs more sky than it does dirt is AOK....!!
I "decommissioned" the delta for the last time today and will ship it to anyone interested for the cost of postage / freight.

Max_Power

Great Video! Man that is a pretty backdrop!! The plane looks like it is doing nice! I may take you up on the postage offer if mine doesnt perform. Its all ready to fly and has been tossed down the hill a few times on test glides, but hasn't made it to the field for a powered run yet. I do think I need to add a launch tab on the bottom. I guess I need to just buck up and go try in the snow/mush, as it will just be dirt/mush after that ...Oh how I wish I still lived in Texas[] Todd

combatpigg

My Feedback: (3)

Todd, your first flight should be powered with a 5x3 prop. Make sure the engine is happy with the prop, that it runs steady without going lean or hot for a 3/4 oz load of fuel. It should run with very little vibration. Check the mounting screws [engine and servos] after every flight.
The Cox rubber prop can be cut down if you make a simple fixture to use that controls the distance from center for the cut. Small changes in diameter produce big results.
Make sure your roll control is very slight [1/8" or less] and that you are starting out with a perfectly straight wing with no twists. Check for twists on a flat table.
Free flighters can sight in on the wings of their planes at arm's length and scan the trailing edge for warps, twists, dips, etc....and so can we.
I'd say that 1/2-3/4 my open framework wings end up warped after covering with iron on and time has to be spent untwisting the wing with 1 panel between my legs while I use the iron to pull the tension of the covering into allignment.
The sheet wing planes aren't prone to this problem, but they always need to be checked.
High speed reveals flaws that can't be compensated for at the TX. The flaws rob speed, too.
If you are going for it in the snow, tow a short ribbon to make finding it easier...!!

Max_Power

So I finally got a chance to maiden my delta built with motivation from this thread. No HotRod engine on it right now, it just has a AP .061 turning a 5.5x4 MA.

A friend launched it for me and it seemed to get in the air really easy and wasn't too bad to trim out. With the light weight of these things even a AP pulls it at a decent sporty speed. It had one weird habit I can't figure out yet though, although I only flew it once.

I don't know if it was the winds higher up but I would just be flying along and it would nose down sharply like it was going to try to outside-loop itself? A bit of elevator(which was WAAY too authoritive at current settings) would pull the nose back up and it would fly around for another 30 seconds or so before it did it again....I was kinda fearing the landing because it was doing this, but when the plane slowed down the tendency seemed to dissapear.

I'm figuring I will try to add nose weight and try it next time. Anyone have any ideas or similar experiences? I'm looking forward to flying it again Its a fun little plane!! As soon as I get this sorted out I plan on modding the firewall a bit and mounting the Fora But I'm kinda glad it wasn't powering it today!!! Todd

combatpigg

My Feedback: (3)

Check the controls for stiffness and zero slop with moderate hand pressure against the servos.
I usually use 2-56 pushrods and slide a tight fitting black FG kite tube over the pushrods for added rigidity.
Bring some plumbers solder to the field and before the next flight try a couple of wraps of it around the engine.

Max_Power

I like the solder idea!! I just happen to have a ton right now ...re-doing a bathroom/sweating copper and one of those lose your solder until you get home from the store with the new roll situations .

I just went over and checked my linkage...which seems pretty good, but balancing by my marks it does seem tail heavy. I guess the theory is tail heavy so you trim nose down to make it fly, then when it gets a bit more on step the nose down trim makes it nosedive? I guess thats my current theory [8D] As sensitive as the elevator was seems like it could happen.

I think a roll of plumbers solder is gonna become a flight box checklist item now, as I would have flown it again if I could have figured out a good way to add some weight on-site. Todd

combatpigg

My Feedback: (3)

Todd, hopefully by the time you add enough solder [to the AP] to get the CG, it will weigh the same as the Fora without lead.
I think there is a good chance of that.
The only other possible issues that could cause sudden dips is the airframe cupping or flexing.
Even if the thrust was off by a fraction, that wouldn't cause random pitch trouble.
Pizza Box Flyers have flat plate airfoils and they dip if you try to fly them level, but for some reason this size and weight of delta fly just fine.

aspeed

Most delta planes need to be trimmed with a reflex (a bit of up all the time) They always have a tendency to go down. Washout is always good too.  An undercambered or cupped wing also has a tendency to zoom down at high speed.  (Pizza Box Flyers and gliders on launch)  I think I will put some solder in my flight box too.  It is good to see someone happy with their AP .06.  There is so much bad press on them that it makes me afraid to get one.  I guess it doesn't quite equal the Norvel so it flunks the reviews.