FlyFly F-86 build

Wingnutz · January 14, 2013, 04:36:34 PM

Okay so I've been working on this...off and on (mostly off) for close to two years..but it's finally coming together. Hopefully it'll be ready for TEMAC EDF Day. (2013)
Challenges along the way have included;
1. the FlyFly F-86's tendency to fold up its wings (in flight...definitely not recommended...ask Michael what happens if this occurs!) added carbon fiber tube and carbon fiber slab wing spars to avoid this (pics included)
2. my fascination with the new generation of high blade count whooshy sounding EDFs...bought a HK 90 mm 12 blade alloy 6S EDF which meant I needed a bigger ESC than I'd ever had before (pic included)
3. the Fly Fly has no rudder and I like rudders (pic included)
4. small wheels, especially ones on retracts have a hard time with ROGO Field bumps which necessitated building a really robust retract system even though I'll try to handlaunch the model (pic included)
5.canopies which are not molded to scale...both canopies I have (FlyFly and PFP) have the windshield arch frame hitting the fuse edge at about 70deg...on a real Sabre, North American or Canadair the frame meets the fuse at 90deg...Frankensteined the canopy frame with tape...not sure it's an improvement (pic included)
6. nose cones (FlyFly and PFP) both look like they belong on the front end of a large mouth bass, not a Sabre (I'm working on getting a glass nose cone from a guy in California who molds more scale ones)
It's been frustrating but fun and educational. Maiden flight will tell if I learned enough!

piker · January 14, 2013, 04:45:33 PM

Lookin' good. I like the way you reinforced the nose gear.

BTW, I hope we get to see that little Crane fly one day too!

sihinch · January 14, 2013, 05:30:26 PM

Wow, Bill, that looks AWESOME! Nice job on the front gear.

Can I ask what size/scale Pilot you used and where it's from, please? That's on my list of things to solve.

I hope you'll let me fly my Hunter with your Sabre?

S

flying saucer · January 14, 2013, 08:49:49 PM

Very nice model Bill, and looks to be a fair size as well for a 90mm. What is your wingspan and expected final weight?

Wingnutz · January 14, 2013, 10:15:18 PM

Rob,
Didn't realize the Crane had made one of the pictures. That's another off and on two years + projects...scratch built and hopefully in the air this season.
Simon,
The pilot/cockpit is a Park Flyer Plastics add-on specifically for the FlyFly F-86. I'm not sure if PFP does stuff for the FlyFly Hunter. Looking forward to flying with your Hunter!
Jeff,
RCGroups guys are coming in anywhere between 6 and 9 pounds depending on battery/motor choices and how much extra stuff is on board. At those weights the model won't be a screamer with the published thrust for the EDF unit I've chosen but if I can come in towards the light end of the weight range, the model will have at least scale performance and should be hand launchable. There's a video on RCGroups of Tom Muir hand launching his FlyFly F-86 by himself. Firm push and the model flys right out of his hand...just like Ronnie's F-16. That's what I'm hoping for.

piker · January 14, 2013, 10:21:35 PM

Ooooo... and I see plans for the M-5

Michael · January 14, 2013, 11:46:22 PM

Nice job on the front gear!

Wingnutz · January 15, 2013, 12:35:22 AM

Quote from: piker on January 14, 2013, 10:21:35 PM
Ooooo... and I see plans for the M-5

Can't fool,you! My build queue is so messed up, I don't know where the M-5 is anymore

flying saucer · January 16, 2013, 01:01:36 PM

If you can keep it at the lower end (about 6lbs) you will have no problem hand launching it. Ronny has 1:1 power to weight (or just over) and it flys fairly scale.

sihinch · January 16, 2013, 10:58:04 PM

Hey Jeff - how are you/Ronnie measuring the thrust from your EDFs? Do you have a scale system rigged up?

Sorry to hijack your thread Bill!

S

Bobmic · January 17, 2013, 08:36:00 AM

Hi Simon since you are testing a bunch of motors and fans, the best way will be to build a mount that will hold the motor to a plate which will than slide over one or two rails along the thrust axis, then attach a luggage scale to the plate.

...I just held the plane nose down on a scale (you can also take a larger piece of foam with an opening that will roughly fit over the nose of the plane)

flying saucer · January 17, 2013, 11:07:29 AM

Quote from: sihinch on January 16, 2013, 10:58:04 PM
Hey Jeff - how are you/Ronnie measuring the thrust from your EDFs? Do you have a scale system rigged up?

Sorry to hijack your thread Bill!

S

we use a Berkley digital scale and a nylon harness that the plane is strapped to. Its always a good idea to measure "installed thrust" to see how much you actually have in the model. We have noticed with good ducting you tend to lose 15-20% of what is achieved on a test bench (or quoted by the manufacturer), with poor ducting it drops A LOT more.

Hope that helps.

Wingnutz · January 29, 2013, 12:27:18 AM

Struggling to deal with ESC location which will balance the model without non-functional ballast.
Since the model came out, FlyFly has moved the recommended CG almost 30mm forward.
My fascination with whooshy 12 blade EDF sounds and choice of an alloy 6S EDF (necessitating a heavy 120A ESC located behind the fan and CG)put extra weight behind the CG.

So, the other night, I hooked all the heavy bits on with the ESC in the back of the cabin area directly above where I think I'm going to hang it in the intake flow. Coming in at 5lb 14oz, the model still balanced slightly behind the recommended CG, but with batteries ooched forward, nose cone and wing tanks added I may be able to balance at the recommended CG with no ballast. With the ESC in stock location, this would have been impossible.
Relocating the ESC also eliminates the need to extend ESC to battery leads and will require only an extension of approx. 3" for the ESC to motor leads.
Sounds more straightforward than it's turning out to be. Working with 10 ga silicon wire, tearing out and re-installing the thrust tube and re-locating the fairing on the EDF has not been great fun!

Wingnutz · January 29, 2013, 08:12:03 PM

Two things happened today.
My new nose cone arrived from Air Sally in California. Thought all Tamiya Golds were the same...nope! So the nose cone is a different colour from the rest of the fuse...

Still, once the nose cone is mounted in the right place I think it's closer to scale than the ones I've tried already.
Took a deep breath and cut the floor of the cabin to locate the ESC ahead of the fan and hanging in the intake stream. It's ended up nearly a foot farther forward than it would have in stock location and with a weight of 5+oz. should get me close to no ballast balance

Attached show the new location of the ESC and the heat sink and capacitors of the ESC hanging in the intake stream.
Now to mount it!

Michael · January 29, 2013, 08:14:50 PM

The nose is nice, and your work is neat and clean.

I'm really looking forward to seeing you fly it.