Ritewing Show and Tell

[BruceN]

I think now I have to come to Australia and buy you a beer, Brosius. Since you made me spit one on my keyboard and all...

PS - sorry to assist in taking your thread off track, Marmot. Anxiously awaiting further news of the repairs...

[a_marmot]

Bro, you are a man of many talents.

[brosius85]

i prefer the invisible character in the middle

cheeky fuc⁣kers

[brosius85]

back on topic...

we need to get you a bungee launcher marmot, that thing is probably a bit big for most handlaunchers.

can't wait to see it flying

[a_marmot]

back on topic...

we need to get you a bungee launcher marmot, that thing is probably a bit big for most handlaunchers.

can't wait to see it flying

I am equally impatient. Yet must work within the constraints of job and family...

But stay tuned. I have a possible solution in the works to the launch problem...better than a bungie if it works!

[a_marmot]

Progress photo: IYF30, FPV style. Getting closer...
Attachment 4818
Note the coroplast-less equipment bays. I decided to try just laying out the equipment in individual cavities in the foam, and laminating to hold in place. The only exception will be the batteries, which will sit flush in open bays.

Woo hoo! After sporadic work over the last 6 months, I finally got the IYF30 up and flying (3rd person). The key was to get the weight down (24 oz AUW), and reduce the elevon throws. It's still a flying brick (17 oz/sqft), but as long as it stays above about 35 mph, she's a screamin' meany.

I played around with various motor and prop combinations (as large as 9x6 at 950 kv!). But I finally settled on a Hyperion ZS2209-24 (1165 kv) with 7x5 APC prop on 4S. Although this is bigger and slower than most people would use for this size wing, it provides >1:1 thrust, yet is very efficient at half throttle. I flew for about 30 minutes on a 4S 2100 mAh, and still had 14.4 V in the tank at the end. This means it should be able to get close to an hour (I still need to test to prove this). It was moving frighteningly fast at this burn rate - ~40mph, which seemed about the optimum tradeoff of control vs. efficiency.

And for all of you out there trying out various bungie systems: I think I might have stumbled onto a workable solution to wing launching: a takeoff IMU!

Background: This wing is quite challenging to fly. It's prone to tip-stalls at low speed, and it's so darn little, everything happens about 10 times faster than my Zeph. Before I got it trimmed up and the CG set, it was SUPER squirrelly - and I was crashing it constantly.

So as a temporary measure, I hooked up a FY-30A stabilizer just to get the darn thing in the air and flying level long enough to work on trimming it up. However, this strategy worked so well (and took so much of the stress out of launching the plane) that I ended up digging into the foam permanently.

The way I have it set up, it's just on/off, and the switch next to it adds a bit of backtrim as well. Thus to launch I just toss it in the air throttle off (pretty much any which-way), and then it rights itself as I throttle up. After gaining some altitude, I turn off the IMU and reduce backtrim. By this time my right (throwing) hand is back on the stick. Very simple, very easy.

Now that the plane is trimmed up, it's almost unnecessary. But it really takes the stress out of it. Gale force cross wind? Not a problem. It's also pretty handy when getting the goggles on, or during other distracting tasks. It's kind of like having a "pause" button. Yet less invasive and fewer failure modes than a full autopilot.

btw, I've seen a few vids of Zephs or other wings pitch-flapping themselves to pieces under IMU control. This is because the pitch gain is set TOO HIGH. Basically with a flying wing you want a medium to large roll gain but a very SMALL pitch gain (almost off!). Ideal settings should make the plane fly (temporarily!) like a big tailed glider with lots of dihedral.

[brosius85]

good news marmot. might be worth looking at a stabiliser on that rap.

[a_marmot]

Hey y'all. Here's a little vid of the IYF30 in action while testing the radio gear. Not really FPV (as I was flying 3rd person), but it is a ground recording of the FPV video feed. Fun little plane! And very tough, as you can probably judge from the video...


View this video on Vimeo

[a_marmot]

IYF30 FPV Maiden: Awesome! Footage in a few weeks when I get back to my video editing station.

Zeph 72: Finally had a marginally successful 3rd-person maiden. It flew for about 15 minutes before I tip-stalled it and nosed into the ground, destroying the center section (again). After rebuilding this thing several times now, I've come to the conclusion that it's just not possible to have 1) light + 2) strong + 3) multi-sectioned. You can have any two on that list, but not all three.

p.s. FY-30A as a launch aid worked great - both planes.

[ritewing]

If its tip stalling and will not recover then your cg is too far aft.
Most of the Zephs will mush in stall situation and can still be recoverd and steered out if cg is on.