Crash's Whatchamacallit

[rockyboy]

I got this very stange set of parts from the collection of our late friend Michael 'Crash' Hancock. It didn't have any aileron servos or horns installed so I'm sure it didn't fly yet - but it had some rough hanger rash on the tail and was missing one verticle stabilizer entirely.

So I'm channeling the spirit of the big guy and looking to create something that flies here.

Measurements for the wing...

And the fuselage with a hole for a tail boom

Making a blank to match the existing vertical stabilizer

And new vert stabilizer covered in white for some contrast.

He had the servo bay holes cut out, so I made a cover/mount for the servo, covered it in white, and epoxied in a control horn.

 

[rockyboy]

Dropping the dimensions in as a flying wing, I get a CG that's 3.95" back from the tip of the wing

https://fwcg.3dzone.dk/?wing_span=4...p_type=0&sweep=4.5&cg_pos=20&show_mac_lines=0

And with the fuselage pushing the motor out from I can certainly see the need to put the tail back on a boom a bit. I ordered a 1/2" tube that should be here later in the week and then I'll start messing around with various lengths of tail to see what works.

 

[Joker 53150]

Nice score! I tried bidding on some of his planes but the costs jumped up quickly and priced me out. His podcasts were the best.

 

[rockyboy]

After the initial handful of planes that went up on eBay, the Angle of Attack podcast hosts moved it to a private site where it's not about bidding, just picking a plane and saying you'll pay shipping. They talked about it in a couple podcasts, and I think there are still some planes available. PM me if you need the address.

 

[Joker 53150]

Sure, shoot me the address and I'll check it out. Thanks!

 

[rockyboy]

So I looked up the motor and find it's recommended to go with a 3s1300 10x5 or a 4s1800 8x4

Then I stuck a prop on the front, a 3s1300 in the belly, and find that it's almost balanced perfectly as a flying wing.

So I don't know what the plan was for the tail boom hole, or if the horizontal stabilizer even goes with this build or not. The tail has some holes that look torn out in a crash, as well as a divot from the leading edge that leads me to think it just coincidentally was built with the same covering but actually goes to a different aircraft.

With that in mind, I'm going to build a battery shelf, double check the CG calculations, bind it with a little reflex in the ailerons, and put it in the "ready for maiden" list

 

[rockyboy]

Battery tray with bumpers installed to put the CG right at the calculated point. Bound up with about 2mm reflex and ready to launch!

 

[rockyboy]

Maiden report: success!

She launched well, and was a little pitch touchy as well as pulled up every time I hit the throttle, so after I got her down safely I added a 1/4oz of lead inside the nose.

Second flight was great! Handled very well - lots of speed on hand, but too easy to lose orientation for me without some additional color contrast.

Luckily for the color contrast changes, I now have incentive to make the change

Third flight it started buzzing almost immediately after launch. I thought "I need to bring it in - I think the prop might be unbalanced or sliding off the prop saver". Didn't even make it though the back leg of the first circuit before the motor flew off the front! I was very proud of my perfect deadstick landing though

In addition to ripping 2 of the motor wires out, the prop banged up the top of one wing and the side of the fuselage when it came free. So since I need to replace some covering on that side anyway, this looks like a good time to add a little more contrast to the color scheme.

Here's the impacted area with balsa plugs glued in. Need to sand and cover and install the new motor and she will be back in the air

 

[Joker 53150]

Nice save on the landing!

 

[rockyboy]

Thanks!

All back together with a few new stripes of white and a new 1100kv motor.

 

[Joker 53150]

I like the look with the trim color.

 

[rockyboy]

Me too - sort of funny how it looks better every time I break it so far

 

[rockyboy]

I should follow up with a flite report here. She flew very well with a healthy amount of down thrust for about 4 flights. Then I made a landing where the prop was vertical and dug into the grass, tearing out the firewall and motor mount.

So I rebuilt the firewall and swapped out the prop mount for a prop-saver rubber o-ring style adapter (and a smaller 8x4.8 plastic prop instead of the 9x6 wooden one) and she's been a great flyer ever since!

Probably have a dozen flights on her all told now - certainly a new favorite model to throw in the car for club meetings at the field or a quick trip down the road.

 

[Joker 53150]

I haven't done it, but have heard that setting the ESC up for a hard-stop instead of freewheeling when no power is applied can help avoid that kind of situation.

What are you using for o-rings on the prop-saver? I've got some therapy stretching bands that work great when cut into small o-rings. They're far stronger and longer working than any regular o-ring I've used.

 

[rockyboy]

I haven't done it, but have heard that setting the ESC up for a hard-stop instead of freewheeling when no power is applied can help avoid that kind of situation.

What are you using for o-rings on the prop-saver? I've got some therapy stretching bands that work great when cut into small o-rings. They're far stronger and longer working than any regular o-ring I've used.

I did have the ESC setup for a hard-stop - which worked great until I did the landing when it hard stopped the prop vertically and I basically froze instead of blipping the throttle to get it horizontal. Completely bad piloting.

For o-rings I picked up a pack of 50 from Amazon for about $6 last spring that turned out to be tougher than the stock ones that have come with any of the motors I've purchased.

 

[Bricks]

Instead of O-Rings we have been using small zip ties, they really work well and still protect the prop unless a really bad crash.

 

[Captain Video]

Is it possible to put landing wheels on it that will raise the wing high enough to prevent "prop" destruction?

 

[Captain Video]

That wing looks really cool. Still no idea what it is and if plans exist?

 

[rockyboy]

I could maybe put tricycle style gear onto it, but that would change how it flys - and I like how it flies now

No idea what it is though - if anyone runs across something like it I'd love to find out more about its past!

 

[Captain Video]

Perhaps recess them enough to protect the prop or make them short enough to not change the flight characteristics greatly?